Ordering Custom Forged Ball Valves? Confirm These Details Before Production Starts ? | drawing approval, marking request, inspection scope

Drawing size tolerance (±0.05mm), material standard (such as ASTM A105), pressure class (Class 150–2500), marking content and position (marking depth 0.3mm), inspection scope (100% water pressure + 10% spot check RT), and sign drawing and inspection plan after then can put into production.

drawing approval

Size & Flange Connection

ASME B16.10 specification divides long and short series very clearly. On a 2-inch 150-pound drawing if it writes 178 millimeters, it shows it is short series, if writes 216 millimeters then is long series. This 38 millimeters drop, will let site workers take welding torch to cut off pipe and re-grind.

10 inches and below sizes, end to end length error is strictly limited within plus or minus 1.6 millimeters. In large petrochemical pipe galleries, once flange appears 2 millimeters deviation, forcefully pulling to butt joint will let connection bolts bear extremely large shear stress. Drawing approval confirms tolerance column writes clearly plus or minus 1.6 millimeters, site assembly then will not get stuck.

Consult ASME B16.5 specification, flange outer diameter, bolt hole center circle diameter and hole opening quantity are all one to one bound. 2-inch 150-pound flange outer diameter is 150 millimeters, above opens 4 pieces of 19 millimeters bolt holes. Pound class increases to 300 pounds, outer diameter will expand to 165 millimeters, hole quantity also doubles to become 8 pieces.

Hole opening diameter on drawing wrongly marks one millimeter, site M16 studs then cannot pass into flange. On drawing these several flange details often are wrongly marked:

• Flange total thickness misses calculating raised face height value
• Bolt holes not according to straddle centerlines principle to carry out array
• Blind hole thread depth shorter than 1.5 times inner hole diameter
• Ring groove bottom chamfer fillet radius turned too small

On 150-pound and 300-pound drawings, this step nominal height is specified as 2 millimeters. When pipeline pressure reaches 400 pounds and above, height marking on drawing must become 7 millimeters. These few millimeters metal protrusion, controls two pieces flange between spiral wound gasket’s compression rebound amount.

On drawing must detailedly write out trapezoidal ring groove’s pitch diameter, groove width and groove depth’s specific numbers. 900-pound flange octagonal gasket ring groove angle is fixed dead at 23 degrees, processing tolerance only allows deviating 0.5 degrees. Factory lathe tool deviates 0.5 degrees, metal seal ring puts inside then will happen line contact leaking gas.

Line of sight passes through flange to enter valve body inner cavity, channel inner diameter size interferes with fluid passing pressure drop. Ordinary drawing will fuzzily mark a DN50, full bore ball valve according to API 6D requirement, inner hole diameter actual measurement needs to reach 49 millimeters above. Inner hole number on drawing if is secretly reduced to 38 millimeters, pig forcefully entering pipeline bound to will get stuck dead in the middle of ball.

ASME B16.34 standard table 3 gives wall thickness drawn a red line. 4-inch 600-pound forged steel valve body, minimum wall thickness is not allowed thinner than 11.1 millimeters. On drawing if only casually marks a 10 millimeters, high pressure fluid produces water hammer impact time, valve body weak zone very easily tears open tiny cracks.

On these several internal sizes, manufacturers extremely easily compress metal materials:

• Valve seat seal ring radial thickness allowance
• Anti-blowout valve stem step width width
• Between ball upper part and valve cover metal clearance value
• Flange neck transition fillet radius size

NPT thread marking will attach a taper data, industry convention is 1 to 16. According to ASME B1.20.1 specification, 2-inch NPT outer thread reference plane effective length is fixed at 17.32 millimeters. Butt welding end wall thickness exceeds 22 millimeters time, drawing must draw out compound type U-V groove shape cross section.

Partial enlarged drawing inside has a string of models complying with ISO 5211 specification. Marking F07, four bolt holes distribution circle diameter then is fixed at 70 millimeters, drills out 4 pieces of M8 thread holes. Valve stem square head opposite side size marks 14 millimeters or 17 millimeters, with gear box inner hole implements H9 and d11 clearance fit.

Unmarked tolerance sizes approval extremely tests mechanical processing common sense. Technical column often prints has “unmarked linear sizes according to GB/T 1804-m level execute” words. On drawing a marked as 100 millimeters outer shape non-fit length, actual object turning will between 99.7 millimeters to 100.3 millimeters float.

BS 6364 standard writes, pipeline temperature low to minus 100 degrees Celsius time, in order to prevent packing freeze hard lose elasticity, gas chamber length must be greater than 250 millimeters. On drawing lacks this long neck’s specific height data, site cooling freezing cold bridge will all the way spread to operation handle.

An 8-inch 1500-pound forged steel ball valve actual weight approaches 850 kilograms. This number controls site crane driver’s lifting weight model selection and pipeline support’s load-bearing estimation. Shipped to site actual object weight if compared to drawing less fifteen percent, factory mostly is cut valve body outer wall’s turning metal allowance.

Pipe network system’s safety redundancy, disperses in drawing various parts’ hidden parameters inside:

• Valve cover double-head studs’ tensile yield strength value
• Pressure-bearing boundary minimum thickness tolerance’s lower limit value
• Operation gear box nameplate on maximum torque value
• Actuator cylinder’s working air pressure lower limit value

On drawing will draw out valve stem inside stuffed a tiny spring and metal steel ball. Spring’s free length is marked as 8 millimeters, compression amount is conventionally set at 2.5 millimeters. Spring force not in place, ball friction produced static electricity cannot be conducted to valve body, potential breaks through 300 volts extremely easily in natural gas pipeline inside causes electric sparks.

Material & Parameters

ASTM A105N is carbon steel forgings’ frequent customer, that “N” represents normalizing heat treatment. After 1.5 hours’ 880°C to 920°C normalizing, metal grains get refined, ensure under minus 29°C environment, impact work value still can keep at 27 Joules above.

If pipeline transported medium contains hydrogen sulfide, drawing must forcibly mark complies with NACE MR0175 standard. Valve body and internal parts’ hardness is dead dead locked at 22 HRC below, prevent happen stress corrosion cracking. Raw material’s nickel content needs to be controlled at 1.0% below, sulfur content even needs to be pressed down to 0.01% within, to satisfy anti hydrogen-induced cracking (HIC) test requirements.

For stainless steel material like F316L, carbon content mark on drawing should be lower than 0.03%, this is preventing post-welding intergranular corrosion’s bottom line. Molybdenum content maintains between 2.0% to 3.0%, used to resist chloride ions caused pitting corrosion. Table below lists four kinds of common forging materials’ yield strength and use temperature ranges, provide for checking Datasheet time reference:

Material Grade	Yield Strength (MPa)	Recommended Temperature Range (°C)	Common Working Condition
ASTM A105N	≥ 250	-29 ~ 425	General Oil & Gas
ASTM A350 LF2	≥ 240	-46 ~ 345	Low Temperature Environment
ASTM A182 F316	≥ 205	-196 ~ 600	Corrosive Medium
ASTM A182 F51	≥ 450	-50 ~ 280	Duplex Steel/High Pressure

Full bore ball valve’s ball surface usually needs to do hardening treatment, electroless nickel plating (ENP) is standard configuration. On drawing if marks ENP thickness as 75 microns, its hardness can reach 800 to 1000 HV. On containing sand oil well production lines, drawing then needs to clearly note spraying tungsten carbide (TCC), coating thickness is usually set at 0.15 millimeters.

17-4PH (ASTM A564 Gr.630) because of its high up to 725 MPa yield strength frequently appears in high pressure valve drawings. Through H1150 heat treatment, this material in keeping strength at the same time can give consideration to toughness. If medium has extremely strong corrosiveness, XM-19 material relying on its two times than 316 stainless steel’s strength, often is chosen as valve stem’s first choice.

In soft seal structure, polytetrafluoroethylene (PTFE)’s temperature resistance upper limit only has 200°C. Pressure exceeds Class 600 or temperature fluctuation relatively large time, drawing will switch to Devlon or polyether ether ketone (PEEK). Below are four kinds mainstream non-metal seal materials’ data performance:

• RPTFE (Reinforced Polytetrafluoroethylene): Filled 15% glass fiber, compressive strength elevates to 15 MPa.
• NYLON 12 (Nylon 12): Water absorption rate lower than 0.2%, suitable for 32 MPa below high pressure normal temperature working conditions.
• PEEK (Polyether Ether Ketone): Bending strength reaches 140 MPa, can under 260°C high temperature continuously operate.
• PCTFE (Polychlorotrifluoroethylene): Low temperature toughness extremely good, is minus 196°C liquid nitrogen working condition’s standard matched material.

Stellite alloy (Stellite 6) overlay welding layer’s thickness needs to keep at 1.5 millimeters above, hardness maintains at 38 to 45 HRC. This kind of metal to metal contact, requires processing precision to reach light wave level, ensure under 520°C high temperature, leakage amount still complies with ANSI/FCI 70-2 standard’s Class V or Class VI.

Class 1500 forged steel ball valve, its shell test pressure will hit to 38.8 MPa, duration time according to API 598 standard, 2-inch valve must not be less than 60 seconds. Valve seat seal test then divides into water pressure test (28.5 MPa) and low pressure air pressure test (0.6 MPa), by this verify under different pressure gradients whether exists bubbles leakage.

Fireproof design (Fire-safe)’s parameters reflect in API 607 test report. Drawing needs to draw out auxiliary metal seal lip structure. When soft seal ring in 761°C to 980°C flames is burned destroyed after, ball will under pressure push lean towards metal lip mouth. Test requires in up to 30 minutes continuous burning inside, through valve seat’s external leakage amount every minute cannot exceed per inch valve diameter 100 milliliters.

Aiming at high frequency switch’s working condition, drawing should clarify valve stem packing’s type. Low leakage packing (Low-Emission Packing) mostly adopts flexible graphite sandwiching metal wire. On drawing if notes satisfies API 622 test requirements, represents this packing after 5 rounds temperature cycles and 100 thousand times mechanical cycles, methane leakage amount will be lower than 100 ppm.

Bolts and nuts’ materials in BOM table inside often are arranged at the end, but play supporting overall pressure’s role. ASTM A193 B7 class bolts matching A194 2H class nuts is carbon steel valve’s standard combination. If is offshore platform environment, drawing will require to bolt surface carry out Teflon spraying or select B7M material, in order to prevent under salt spray environment’s stress corrosion and fast rusting.

Torque parameters are actuator model selection’s basis. Drawing usually will give three torque values: Break to Open maximum torque (BTO), Running torque (RUN) as well as End to Close torque (ETC). A Class 900, 8-inch full bore ball valve, its BTO value may high up to 3500 Newton meters. In confirming drawing time, must ensure actuator’s rated output torque carries 1.3 to 1.5 times safety margin.

Operation Method & Space

For 2-inch Class 150 forged steel ball valve, standard configured handle length usually is at 230mm to 280mm. If drawing marked rotation envelope circle diameter reaches 600mm, while site two parallel pipelines’ center distance only has 400mm, handle dialed to 45 degrees position then will by side flange dead dead stuck.

Under Class 800 high pressure working condition, 2-inch ball valve’s opening torque often exceeds 60Nm. If handle moment arm matched on drawing is too short, force applied by operator single hand if exceeds 250N, valve stem extremely easily happens permanent torsional deformation. Confirming drawing time, must require manufacturer to give maximum operation torque data, and check moment arm length whether complies with ergonomics.

When diameter enlarges to 6 inches and pressure reaches Class 600 time, torque will soar to 1200Nm above, this time drawing must reflect worm gear reduction box. Common speed ratio is set at 40:1 or 60:1, represents handwheel rotates 10 to 15 circles then can finish one time 90 degrees open close action.

In petrochemical pump station this kind of high density pipe layout area, handwheel’s facing direction often compared to valve main body more occupies place. If drawing marks handwheel diameter as 500mm and vertically upwards, while above exactly has cable bridge passing through, space headroom if less than 600mm, later period fundamentally unable to carry out manual emergency operation.

Automation modification’s demand usually reflects on top’s ISO 5211 connection plate size. A standard customized drawing will enlarge display drive pad. F07 connection plate represents bolt circle diameter is 70mm, opens 4 pieces of M8 thread holes. Valve stem top end’s processing precision must be controlled within h9 tolerance, 17x17mm square head if processed into 17.5mm, matched actuator bracket then unable to smoothly press in.

• 2-inch F05/F07 connection plate: matches 14mm or 17mm square head
• 4-inch F10/F12 connection plate: matches 22mm or 27mm square head
• 8-inch F14/F16 connection plate: matches 36mm above double keyway valve stem
• 12-inch F25 connection plate: matches multiple keyway or spline drive

Pneumatic actuator’s volume often is valve body itself’s three times above. Drawing must present total height after actuator is fully expanded. Taking an 8-inch Class 300 ball valve as example, after mounting single acting spring return actuator, overall height may break through 1500mm. If in offshore platform this kind of floor height limited module inside, miss looking this 1.5 meters height mark, hoisting time then will find actuator top end will strike upper layer’s steel beam.

Site experience indicates, side mounted bypass valve most taboos actuator horizontally lying. Actuator with self weight exceeding 80kg if not adds installing special support base, long term suspending in air will produce huge torque, leading to valve stem stuffing box one side pressed seriously, less than half a year then will appear naked eye visible medium outward seeping.

If pipeline wraps 100mm thick rock wool insulation layer, neck extension height on drawing at least needs to reach 150mm. Reserved out 50mm space is in order to ensure operation handle will not sink into insulation layer inside. Drawing if not marks clearly this stretch out length, insulation worker finishes construction after, operator even handle is where all cannot touch.

On drawing needs to clearly note precise value from center line to ground operation box top, usually according to 1.2 meters or 1.5 meters customize. This extension stem inside must fill anti-corrosion grease, and bottom needs to carry exhaust valve mark. If drawing misses drawing bottom drainage pipe, rain water accumulates existing in extension pipe inside, severe cold season will freeze to become ice pillar, completely locks dead ball valve’s rotation function.

Space’s interference not only exists in horizontal direction, also exists in vertical direction’s bolt disassembly space. Flange connection drawing needs to mark out extra distance needed for retreating bolts. Class 1500 ultra high pressure valve, bolt length may reach 300mm. If valve lower part tightly sticks to concrete foundation, clearance insufficient 100mm, once gasket damages, maintenance worker fundamentally unable to take out bottom bolts to carry out replacement.

• Left right clearance: keep 1.5 times handle length’s space
• Upper clearance: reserve 200mm used for disassembling actuator top cover
• Bottom clearance: at least reserve 1 time bolt length used for core pulling
• Lateral clearance: reserve 300mm used for replacing packing gland

For automated ball valve carrying limit switch or solenoid valve, drawing must draw out junction box’s opening direction. Conventional requirement opening faces down or lateral, in order to prevent condensed water following along cable line flowing into junction box inside. Drawing marked G1/2 or NPT1/2 interface position if exactly facing wall, site threading pipe then unable to press into wiring head, finally only can tear down actuator to re-adjust installation phase.

On high altitude pipeline, drawing should mark clearly indicator plate’s enlarged size. If indicator plate diameter only has 50mm, ground operation personnel at 10 meters away unable to judge valve is fully open or fully closed. Increasing a large size red green flag indicating mark, data density although small, yet can significantly lower wrong operation’s probability.

Usually requires actuator’s output torque is valve wet torque’s 1.3 times to 1.5 times. If is switch frequency extremely high working condition, safety factor even needs to be pulled high to 2.0. Confirming drawing time, compare torque curve chart provided by manufacturer, ensure under lowest air supply pressure (usually is 0.4MPa), actuator still can push move ball under high pressure difference.

marking request

Compliance & Safety

API 6D specification twentieth edition clarified nameplate on must contain 14 items parameters. For a NPS 8 (8-inch) Class 600 forged steel ball valve, design pressure is about 10.2 megapascals. If in high pressure gas transmission station mistakenly installed low pressure class valve, pipeline raising pressure after will cause violent vibration even connection part tearing.

Containing hydrogen sulfide (H2S) sour natural gas environment under, carbon steel A105N valve body must pass through normalizing heat treatment. NACE MR0175 standard specifies this kind forging hardness strictly forbidden to exceed 22 HRC. Valve body outer shell hit on “NACE MR0175/ISO 15156” words, prevent site taking ordinary carbon steel ball valve mistakenly using to high corrosion wellhead.

Every set passed inspection ball valve will at valve neck position leave unique Heat No. This string characters corresponds to an EN 10204 3.1 material certificate, recording this batch steel ingot from smelting to forming’s all physical chemical data:

• Carbon content (C) controlled at 0.22% below to guarantee welding performance
• Yield Strength must reach 250 megapascals above
• -46 degrees Celsius low temperature impact test under absorbed energy not lower than 27 Joules
• Chromium (Cr), Nickel (Ni), Molybdenum (Mo) etc. alloy elements’ actual measured percentage
• Intergranular corrosion test (aiming at stainless steel)’s qualified judgment report number

Sold to EU market pressure-bearing equipment is restricted by PED 2014/68/EU directive. Nameplate on must mark maximum allowable working pressure (PS) and corresponding temperature limit (TS). A design upper limit being 350 degrees Celsius F316L stainless steel ball valve, if nameplate lacks TS parameter, in project acceptance link will be directly torn down returned goods.

Petrochemical installation to volatile organic compounds (VOCs)’s fugitive emission requirement reaches 100 ppmv below’s seal class. API 624 standard test requires valve to experience 310 times open close cycles.

API 607 fire test puts valve placed in 760 degrees Celsius to 980 degrees Celsius flames inside continuously burning 30 minutes. Carrying “Fire Safe” steel stamp ball valve, in polytetrafluoroethylene soft seat burned destroyed after, ball will and metal valve seat edge form 0.1 millimeter wide mechanical hard seal.

Before leaving factory’s shell water pressure test pressure is rated pressure’s 1.5 times. Class 1500 forged steel valve body needs to under 31.2 megapascals pressure stabilize pressure 120 seconds to 300 seconds. Quality inspector at flange side face knocks down carrying factory code’s inspection badge, badge number and before leaving factory water pressure test drawing curve one to one correspond.

Valve end’s connection method mark directly relates to pipeline butt joint’s precision:

• NPT 1/2 represents 60 degrees taper angle’s pipe thread connection
• RF indicates seal face roughness at 3.2 microns to 6.3 microns between
• BW groove mark needs to comply with ASME B16.25 specified 37.5 degrees cut angle
• RTJ ring joint face needs to mark groove’s ring number (such as R24)
• SW socket welding bore needs to correspond to specific pipeline wall thickness class (Sch 80)

ASME B16.34 standard to valve body minimum wall thickness has mandatory requirement. NPS 3 (3-inch) Class 300 forged steel valve, pressure bearing wall thickness cannot be lower than 7.6 millimeters. Pneumatic steel stamp’s knocking depth is limited at 0.2 millimeters within, preventing too deep notch in long term high pressure alternating load under evolving into fatigue crack starting point.

Stainless steel nameplate usually uses 304 or 316 material, thickness not lower than 0.8 millimeters. In offshore platform’s salt spray environment under, ordinary aluminum nameplate will in 6 months within corrode peel off. Custom order should require using Monel 400 alloy rivets, avoiding different metals contacting causing galvanic corrosion leading to nameplate lost.

Three layer structure coating system (epoxy zinc rich primer + epoxy micaceous iron intermediate coat + polyurethane top coat)’s total dry film thickness needs to reach 250 microns. Nameplate is installed on valve stem one side’s bracket on, rather than directly pasted, preventing paint coating covering critical flow direction arrow mark.

CE mark beside four digits number (such as 0035) represents NB notified body. TÜV etc. certification bodies through this string number to production manufacturer’s PED H module quality system carry out remote supervision. Auditor in site patrol checking time, will according to nameplate on Serial Number randomly spot check two years ago’s assembly records.

CIS countries’ EAC certification requires nameplate handwriting clearly visible. Mark size strictly forbidden smaller than 5 millimeters, ratio being 1:1 square. Nameplate not only lists Russian product name, also needs to clearly note valve in minus 60 degrees Celsius extreme environment under’s material embrittlement risk level, ensuring complies with Russian GOST standard’s safety requirement.

Buried service fully welded ball valve (Buried Service) because valve body deeply buried surface below 2 meters, conventional nameplate unable to be read. Factory needs to take recording all performance parameters stainless steel plate fixed at extended valve stem top end operation box inside. Scanning operation box cover inner side’s laser engraved QR code, can directly call out this valve’s radiographic testing (RT) film.

Valve seat leakage class (Leakage Class) marking usually according to ANSI/FCI 70-2 standard. Hard seal ball valve if marked as Class V, represents under test pressure every inch nominal diameter’s allowable leakage amount only is every minute 0.05 milliliters.

Custom Marking Requirements

Engineering EPC contractor Fluor or Technip provided P&ID drawings up to hundreds pages, covering tens of thousands pipeline nodes. Purchasing party requires on every set valve hang on containing equipment tag number (Tag Number)’s nameplate. A numbered as XV-204B’s tag number sign, lets construction team in pipe gallery maze inside take this 8-inch ball valve accurately locate to phase two catalytic cracking unit’s designated flange opening.

Factory uses thickness 1.2 millimeters 316 stainless steel plate cut into 20×60 millimeters rectangle. Typewriter takes letters and numbers knock out 0.3 millimeters raised, uses a diameter 2 millimeters, length 300 millimeters multi-strand stainless steel wire rope pass through sign round hole, bound tied on valve stem bracket on.

Prohibit oil prohibit water working condition’s customized requirement reflects on special color mark on. Used for purity 99.9% high pressure oxygen pipeline ball valve, in dust free room finished degreasing treatment after, surface sprays a width being 15 millimeters RAL 5012 light blue color band. Quality inspector on valve body extra knocks “O2 Cleaned” words, preventing worker wearing touching machine oil gloves touch inner cavity.

Marking Category	Material & Size Requirement	Data Display Format	Site Application Scene
Hang Plate Tag Number	316SS, thickness 1.2mm	Character height 6mm, raised type writing	P&ID drawing actual object matching
Warning Label	Aluminum back glue, 50x100mm	Black background yellow words, SimSun bold	Marking operation state limits
Smart QR Code	Laser micro engraving, 25x25mm	300dpi resolution array	Tablet computer scan code consult
PMI Re-inspection Stamp	Low stress steel stamp, 0.15mm depth	“PMI-OK” or “100% PMI”	Alloy material spectrometer confirm

Spectrometer (PMI) 100% re-inspection requirement in special alloy orders extremely common. Site testing personnel holding handheld X-ray fluorescence spectrometer aiming at duplex steel F51 valve body scan. Screen displays chromium (Cr) content at 22.5%, nickel (Ni) content 5.8%, inspector beside original factory heat number uses low stress steel stamp knock on “PMI-100%” mark.

Prevent wrong operation hang plate (Car Seal) uses red green two colors distinguish normally open and normally closed state. 50×100 millimeters red aluminum plate on uses 30 millimeters large font prints “CSC” (Car Seal Closed). Maintenance worker sees hang plate, then knows pipeline relief valve equipped with metal locking lead seal, applying 80 Newton meters torque unable to turn handle.

Valve body neck leaves out a piece 25×25 millimeters flat surface, 50W optical fiber laser marking machine in 0.05 seconds within ablates out 300dpi resolution black white matrix. Worker holding explosion-proof iPad scans code, screen jumps out size being 15MB PDF assembly general drawing and material test report.

Shipped to Russia Yamal Peninsula LNG project ball valve faces minus 50 degrees Celsius extreme cold. Installing time valve body outside wraps a layer thickness being 100 millimeters polyurethane foaming insulation layer. Purchasing order writes clearly add welding a length 120 millimeters 304 stainless steel nameplate bracket, take containing 14 items parameters main nameplate extend to insulation layer outside.

Customized requirement list also will contain specific leaving factory digital information:

• Packing torque: Gland flange engraved 45 N·m, guard against maintenance worker twisting too tight stuck dead valve stem.
• Lifting weight: Exceeding 50 kilograms valve body sprays “WT 85 KG”, provide crane driver select load-bearing lifting belt.
• Internal number: Knock engrave 12 digits SAP material code, convenient for warehouse scan code input ERP system.

Factory leaving factory before for valve assigns specific LDAR code, such as V-8021. Code uses diameter 3 millimeters steel stamp knocks at flange outer circle, recorded in containing 2000 detection points ledger table inside.

Buyer requires using thickness being 250 microns polyurethane white top coat, on pneumatic actuator cylinder surface sprays “Sinopec Phase II” project name. Template printed Arial font height set as 30 millimeters, sunshine exposure under 5 years not fade color not turn yellow.

Different mediums pipelines through anti-corrosion paint color code carry out intuitive distinguishing. Concentration 98% sulfuric acid pipeline selects RAL 1023 traffic yellow, carrying 30% solid particles slurry pipeline uses RAL 9005 deep black. Factory painting before, at valve neck side face uses high temperature resistant tape covers out a piece 30×30 millimeters paint-free area.

Reserved paint-free bare metal window satisfies future period ultrasonic thickness gauge calibration demand. Detection personnel takes coated full couplant probe sticks on 30×30 millimeters square block on. Thickness gauge screen displays reading as 8.5 millimeters, complies with ASME B16.34 standard for 2-inch Class 300 level forged steel valve wall thickness limit value.

Marking’s Method

NPS 4 Class 900 A105N valve body minimum wall thickness is 16.3 millimeters. Traditional casting valve carries raised casting font, forged metal surface only can through physical means forcefully press in characters.

Conventional ordinary steel stamp adopts sharp V type font outline. Worker uses 3 pounds heavy iron hammer violently strikes steel stamp rod, on metal surface leaves 0.5 millimeters deep notch. In high frequency alternating pressure pipe network inside, V type groove bottom easily produces stress concentration phenomenon, gradually evolves into tiny fatigue crack.

Containing 25% chromium element super duplex steel F53 material to micro cracks extremely sensitive. Factory requires adopting low stress steel stamp (Low Stress Stamping) carry out marking. Stamp surface processed into round smooth dot matrix type spherical surface, curvature radius controlled at 0.2 millimeters. Pneumatic impact gun at 0.6 megapascals air pressure under knocks out deep 0.15 millimeters U type pit.

MSS SP-25 specification explicitly specifies: Pressure bearing load component surface knocking mark, its indentation depth must not destroy this component design calculation formula inside specified minimum wall thickness allowance.

CNC engraving (CNC Engraving) provided millimeter level typesetting precision. Three-axis machining center main shaft clamps diameter 1.5 millimeters hard alloy ball nose milling cutter. Cutter at 12,000 RPM rotation speed rapidly rotates, feed speed set as every minute 300 millimeters, at flange side face mills out 14 digits letters heat number.

CNC program takes engraving depth locked at precise 0.25 millimeters. Typesetting font mostly adopts industrial level DIN 1451 standard character library. Number “8” and letter “B” inner concave radian is deliberately pulled large, site supervisor at 1 meter away relying on natural light then can clearly distinguish.

50 watts power generator shoots out wavelength 1064 nanometers laser beam. Galvanometer controls light spot on 20×60 millimeters 316L steel plate on high speed scans, 4 seconds within ablates away thickness 0.05 millimeters surface layer metal.

Laser high temperature produces black oxide layer, with silver white stainless steel background color forms high contrast ratio.

• Typesetting engraving 12×12 millimeters size matrix QR code
• Accommodating 256 characters length material detection report link
• Handwriting can bear 500 hours neutral salt spray box corrosion test

Operator uses diameter 2.5 millimeters containing cobalt high speed steel drill bit. Valve neck thickened step place is drilled out four pieces depth precise as 4 millimeters blind holes, drill bit absolutely will not penetrate thick solid pressure bearing shell.

Four pieces diameter 2.4 millimeters half round head knocking rivets (U-drive) are smashed into blind holes inside. Shipped to offshore drilling platform order, rivet material designated as Monel 400 alloy. Ordinary 304 rivets in sea wind salt spray inside will happen galvanic corrosion, less than 6 months then will from blind holes inside break fall off.

Site assembly instruction manual prompts: Nameplate fixing blind hole should locate at flange outer edge or thickened structural part on, blind hole bottom and internal fluid channel between metal solid wall thickness must be greater than 3.2 millimeters.

Operating in minus 196 degrees Celsius extreme low temperature LNG ball valve, outside wrapping thick up to 150 millimeters cold insulation layer. Welder in assembling before, takes a piece length 200 millimeters, thickness 3 millimeters 304 stainless steel long strip bracket welded at valve cover upper part.

Carrying tag number information nameplate is riveted at extended bracket top end, exactly sticking out aluminum insulation outer skin 50 millimeters. Patrol checking personnel along pipe gallery walkway patrols, eye level height can read tag number XV-8802, saves cutting open polyurethane foaming layer’s trouble.

Spraying template typing (Stenciling) satisfies long distance visual inspection demand. 300×300 millimeters polyester film template tightly sticks on pneumatic actuator’s aluminum cylinder on. Painting worker holding caliber 1.2 millimeters spray gun, evenly sprays RAL 1023 yellow epoxy top coat.

Template hollowed out area reveals height 50 millimeters flow direction arrow and “SOUR GAS” acid gas medium mark. Paint film gauge measured out dry film thickness reaches 120 microns. 25 degrees Celsius room temperature under, coating passes through 45 minutes surface dry, firmly attaches on equipment surface.

Temporary hang plate uses 316 stainless steel wire carries out binding. Diameter 1.5 millimeters multi-strand steel wire rope passes through 35×70 millimeters laser engraved tag number plate. Worker takes steel wire on gear box handwheel’s spokes on winds two circles, threads into a section long 15 millimeters red copper crimping sleeve.

inspection scope

Inspection & Test Plan

Factory sent over inspection table usually long up to over ten pages, densely packed fills up a whole computer screen. Buyer has to take line of sight stare tightly at fourth column, there marks checking action’s authority level. Taking 8 inches bore, 900 pound class forged ball valve to speak, shell iron wall thickness exceeds 45 millimeters. Hitting pressure time once finds needle eye size leaking water point, tens of thousands bucks material fee all hits water float.

Encountering H hold point for inspection, workshop works to this step must pull switch stop machine. Buyer representative not arrives at scene to sign, machine absolutely not allowed to continue turning. Table fifth column’s test basis similarly hides tricks, international API 598 pressure test specification requires using 1.5 times rated pressure inside hit water. Workshop small factory in order to rush delivery date, often secretly according to 1.25 times water pressure muddle through handing over task.

Running into high sulfur natural gas pipeline order, internal parts all changed to F51 duplex stainless steel. Stationed factory personnel has to take up stopwatch, stand at one side dead stare acid environment simulation test’s soaking water pool. Less than 720 hours one minute all not okay. Only looking at paper surface material report cannot guard against forging, finding a clerk change an electronic version date even two minutes all no need to use.

Buyer needs in table inside write clearly upstream material must carry 3.2 certificate. Checking personnel runs to steel making factory check heat number, takes calculator verify molten steel inside carbon equivalent CEV value is dead dead stuck at 0.43 below. Here lists several pieces of daily extremely easily missed checking original documents:

• Entering furnace roasted out heat treatment temperature curve chart
• PTFE plastic valve seat purchasing invoice and batch number
• Spraying paint before grinding to Sa2.5 level roughness report
• Lock nut tensile pulling breaking test original record

Holding handheld instrument at bright silver ball surface hit one shot, screen on nickel element value jumps not to 10% to 14% this range. Manufacturer patting chest guaranteeing 3.16L stainless steel parts immediately reveals original shape, assembly workshop main door all cannot enter.

Worker taking big wrench twist valve time’s hand feeling, has to use carrying digital display machine measure calculate. Pipe diameter 150 millimeters ball valve at normal temperature not passing water time, opening force leaving factory set at 350 Newton meters. Exceeding this number, pipeline worker hanging extension rod also cannot break move. Assembly table on small worker often toward pipe cavity inside stuffs full butter, borrowing slippery grease deceive test machine.

On list adds mandatory attached clause, taking high pressure water gun take inner cavity wash clean clean. Wipe dry moisture one drop lubricating oil all not allowed to wipe, forcefully dry turn. Instrument panel on jumped out starting reading and running reading, originally unchanged copy into shipping list inside file. Buyer often will on paper surface bury several actual object spot check hidden piles:

• Taking grid paper stick on iron skin measure 12 point positions wall thickness
• Valve stem anti-fly out step uses caliper measure out 2 millimeters allowance
• Flange face water line groove depth measures out 3.2 microns
• Anti static small spring connects multimeter measures out lower than 10 ohms

Pressure testing worker quietly twists dead water inlet pipe on small cut-off valve, pipe inside pressure already dropped completely dial needle still one bit not moving. Paper surface requires pipe two ends each installs a piece meter, reading upper limit buys two times test pressure’s. Dial needle steadily stops at dial face exactly middle position, water pressure drops half grid naked eye immediately can see clearly.

Specification document requires test water temperature keep at 5℃ to 50℃, north January workshop tap water temperature freezes ice dregs. Rubber O-ring freezes hard loses elasticity, perfectly intact valve throws into water straight outward bubbles. Inspector lets worker toward water sink inside throw a piece high power heating rod, thermometer rises to 22℃ then afresh walk one time procedure.

Air pressure test hit inside compressed air only has 0.6 megapascals. Sunk at water tank bottom valve often bubbles out hair strand thin white bubbles. Workshop supervisor stubbornly says is water pipe inside not exhausted clean bottom gas. You on list add one sentence quietly soak in water look 3 minutes. Bottom face bubbles out 1 millimeter size bubbles successively upwards float, on spot take hammer knock waste tear open re-do.

Carbon steel surface overlay welds a layer corrosion resistant 625 alloy, manufacturer in order to save welding wire takes 3 millimeters thickness cuts off half becomes 1.5 millimeters. Flaw detector holding ultrasonic thickness gauge every interval 5 centimeters hits one point. Taking shot out X-ray film facing high light lamp find black point, find 0.5 millimeters black shadow mixed in bright white place, whole piece valve body originally unchanged loads car returns to repair welding.

Non-destructive Testing Proportion

Taking 600 pound class fully welded ball valve to speak, factory party default RT (radiographic) spot check proportion often only has 10%. Pipeline at construction site one passes natural gas, remaining 90% blind zone inside as long as hides a piece long up to 2 millimeters incomplete penetration crack, tens of kilometers pipeline then has to emergency stop gas troubleshoot.

Requires adjusting up to 100% shoot X-ray fully check, single piece valve cost upwards jumps rises 3000 bucks around. Workshop director takes ASME B16.34 specification inside bottom line standard to press price, mouth inside mutters low pressure 150 pound pipe fittings doing 20% spot check totally complies with rules.

Ultrasonic testing (UT) checking thick wall forgings compared to shooting X-ray saves money, probe at steel surface sweeps one circle only needs tens of bucks labor time fee. UT waveform chart totally relies on flaw detector’s naked eye and hand feeling, probe deviates 3 degrees angle, deeply hidden at 45 millimeters thickness under white point defect then sweeps not out. Buying bill before in contract adds note, thickness exceeding 50 millimeters flange neck, using iridium-192 radioactive source honestly fully shoot 4 sheets films.

Checking surface crack relies on penetrant testing (PT) or magnetic particle testing (MT). Many purchase orders on scantily writes do PT check, arrived at workshop finds worker only at two ends flange seal water line zone paints red potion. Valve stem with ball friction that T type slot mouth, extremely easily at lathe processing time produces tiny tearing, not smearing penetrant liquid fundamentally cannot see out that piece 0.1 millimeter wide dark pattern.

On drawing takes valve body transition section, lifting lug welding place uses red pen circles out, marks on 100% PT full coverage. A can DPT-5 model red penetrant sprays go up, room temperature 25℃ under has to quietly wait for 15 minutes. Small factory worker rushing night shift, sprayed finished less than 3 minutes takes rag wipe off painted white developer, can find out fine crack purely belongs to hitting great luck.

Forging is thousands of tons hydraulic press smashed out solid iron lump, internal compared to casting piece denser. A105 carbon steel at forging cooling stage extremely easily appears white point and folding. Holding flaw detection report checking goods time, see clearly level two flaw detector signed report sheet on, defect rating level is not is strictly stuck at JB/T 4730 standard level one qualified line on.

Accompanying goods traveling flaw detection films firmly cannot let factory party lock in their own iron skin cabinet inside. Bring strong light film viewer go to site check receive, facing list take different parts checking rules clearly understandly list on paper, according to this copy list one by one check accept:

Flaw Detection Part	Inspection Method	Requirement Proportion	Rejection Defect Size
Pressure bearing valve body main weld seam	RT (Radiographic)	100% full check	Long strip shape slag inclusion > 6mm
Valve stem and ball connection slot	PT (Penetrant)	100% full check	Any size linear crack
50mm above thick wall section	UT (Ultrasonic)	100% full check	Equivalent defect > Ф3mm
Lifting lug and bracket fillet weld	MT (Magnetic particle)	20% spot check	Porosity cluster diameter > 1.5mm

Radiographic film blackness value places at 1.5 to 4.0 between then considered meeting standard, film puts under strong light lamp white vast a piece, shows exposure time shrinks water at least 2 minutes. Inspection representative calls stop workshop progress, takes pipe fitting re-lift into thick lead room, makes up full 20 minutes exposure time then washes a sheet clear film out.

Checking hands not only stretch into assembly workshop, also have to toward upstream forging factory inside dig. Buyer issues purchasing outline writes clearly, purchased back rough solid forging does 100% ultrasonic scanning. Flaw detector screen on appears height exceeding baseline wave 20% clutter, this piece weighing 300 kilograms steel ingot even going on lathe cutting qualification all does not have, on spot cut off scrap process.

Encountering natural gas anti-corrosion working condition, ball valve inner cavity overlay welds a layer 3 millimeters thick Inconel 625 alloy material. Two kinds different grades molten steel melt together, interface cold crack probability multiply times upwards flips. This step working procedure’s PT penetrant does two times, welded finished ground flat does one time 100% check, entered furnace finished 620℃ annealing cooling leaves furnace, then makes up one time 100% check.

Same one part using carbon arc air gouging digs open re-repair welding times, absolutely not allowed to exceed 2 times. Third time shoots out exceeding 2 millimeters porosity, whole set valve body immediately smashes steel stamp scrapped. Repaired after flaw detection scope from original damaged point, toward two ends each extends 50 millimeters area enlarges scanning.

Pressure Test

Ten inches bore, 1500 pound class fully welded ball valve is by four root steel wire ropes hoisted up pressure test stand. Worker takes thickened blind plate seals dead two ends flange, turns on plunger pump toward pipe cavity inside injects water. According to design pressure’s 1.5 times calculates, shell water pressure in one minute within is forcefully pushed high to 375 bars. Hundreds of atmospheres in iron wall internal horizontally dashes vertically hits, a piece needle tip thickness crack will take high pressure water column like sharp arrow same spray out five meters far.

ASME B16.34 specification requires dial face measuring range must be at test pressure’s 1.5 to 4 times between. Taking a piece maximum measuring range 50 megapascals meter go to measure 10 megapascals water pressure, dropping a 0.5 megapascals pressure naked eye fundamentally cannot see out dial needle shaking. You have to walk around to dial face back face, check that piece by metrology bureau pasted green calibration label, expired exceeding 6 months meter reading all void.

Factory figuring saving money often one year half year not changes test pressure water, pool inside floats iron rust and oil stain stench. Checking stainless steel valve time brings test paper, water inside free chloride ions exceed 30ppm, several months later pipe fitting internal then will grow out a layer densely packed rust spots.

API 6D specification white paper black words writes clearly, 8 to 18 inches valve shell hitting pressure must steadily stop enough 5 minutes. Taking piece rate wage worker figures saving trouble, seeing dial needle runs to top, pinching stopwatch counts 90 seconds then pulls out pipe releases water. Stationed factory member then has to move a folding stool sits at pressure test stand front, eye inside dial needle not walked finishing 300 seconds, don’t think touching pressure relief valve one bit.

Testing pressure before not taking pipe inside air exhausts clean, dial needle will like electrocardiogram same back and forth jump. Hitting water before has to take handle shake to 45 degrees half open position, let ball and valve seat gap all wide open. Inspector climbs up stand twists open top exhaust small cut-off valve, stares at water outlet. A string bubbles spits finished, sprayed out is a strand finger thickness, no broken layer water column, this time then can shut dead cut-off valve continues upwards hitting pressure.

Water pressure shell passes through, high low pressure seal test meaty part just opens stage.

• High pressure water seal takes pressure drops to rated value’s 1.1 times, hard seal ball valve allows every minute dripping down two three drops water.
• Soft seal’s polytetrafluoroethylene (PTFE) valve seat must achieve “zero dripping leaking”, pad a sheet dry white paper at bottom, wait 3 minutes pick up cannot have a trace water stain.
• Low pressure air seal changes using 0.6 megapascals compressed air, several tons heavy iron lump takes overhead crane hoist, whole piece soaking into two meters deep clear water pool bottom.

Thickness 0.5 millimeters processing error, by viscous industrial grease one pastes, soaking in water tank inside half bubble all bubbles not out. Forcefully order worker takes degreasing solvent take inner cavity wash shiny bright, take strong light flashlight shine inside, metal surface reflects dry cold light then enters water. Even if is a trace hair strand thin leaking gas, at water bottom also will become successively continuous white bubbles upwards dart.

Pipe two ends same time hit into 100 bars high pressure water, inspector twists open valve body exactly middle blowdown hole. Finds a root transparent plastic soft hose puts on hole on, another end inserts into filled clear water beaker inside. Two ends high pressure water totally relies on two pieces valve seats dead dead block, beaker inside quietly wait 2 minutes, half bubble all not allowed to float up.

Minus 2 degrees penetrating wind blows into workshop, two tons heavy big valve fills cold water. Iron skin meets cold shrinks, water cavity volume becomes small, originally steady as Mount Tai dial needle forcefully downwards dropped 3 bars. Workshop director takes thermal expansion cold contraction to argue, you have to let people move come two sets high power hot air blowers facing blow, forcefully take test environment pulls back 15℃ passing line then re-test.

Encountering environmental protection requirement extremely harsh chemical factory order, micro leakage test not uses water and air, all changed to concentration 99% helium gas. Quality inspector holding a root like dog nose same probe going around valve stem turns circles, instrument screen on leakage number is dead dead stuck at every second 10’s negative 6 power cubic centimeters.

Liquefied natural gas (LNG) project inside pipe fittings, test pressure stand has to move into two meters deep explosion-proof ground pit inside. Whole forged steel ball valve soaks into minus 196℃ liquid nitrogen pool inside freezes thoroughly. A piece 4-inch 300 pound class ball, at least needs to in bubbling white gas pool inside soak full 2 hours. Wait until inserted in pipe wall inside thermocouple measures out internal temperature completely stabilizes, then changes on purity 99.99% helium gas carries out high pressure check leak.