BW Fittings Materials: ASTM A234, A403, A815, B366

BUTTWELD FITTINGS MATERIALS

Carbon steel buttweld fittings are common for pipelines and process piping in the oil and gas and power generation industry, stainless steel fittings are for higher temperature, pressure and corrosion applications (desalination, pharmaceutical and, food sectors).

Let’s dive into the three main groups of materials for buttweld fittings, ASTM A234 (carbon/alloy pipe fittings), ASTM A403 (stainless steel), and ASTM A815 (duplex and super duplex BW pipe fittings).

Important to note that the material of the pipe and the buttweld fitting shall match (for example, an ASTM A106 Gr. B pipe shall be connected to an ASTM A234 WPB BW fitting, or an ASTM A312 T304 pipe has to be welded to an ASTM A403 WP304 fitting and so on). It is not possible to use pipes and buttweld fittings of different materials. Likewise, the size of the buttweld fitting and the size of the connected pipe shall match.

The fittings materials compatible with specific pipes are shown in the piping materials match table.

CARBON/ALLOY STEEL BUTTWELD FITTINGS (ASTM A234)

The ASTM A234 specification covers carbon steel and alloy steel pipe fittings (butt weld) for high-temperature service.

A234 WPA, WPC and, WPC fittings match ASTM A53, ASTM A106 and, API 5L Gr. B pipes. A234 WP1 to WP91 butt weld fittings match ASTM A335 chrome-moly pipes.

The ASTM A420 specification covers low-temperature carbon steel butt weld fittings to match ASTM A333 Gr.3 and ASTM A333 Gr. 6 pipes; the ASTM A860 specification (WPHY42, WPHY52, WPHY56, WPHY60) covers high yield wrought carbon steel fittings that match high yield API 5L Gr. X42, X52, X56, X60 pipes.

Pipe Fittings Materials: ASTM A234 for Carbon and Alloy Steel Butt Weld Fittings

ASTM A234 Chemical Composition

Chemical composition of ASTM A234 Carbon and Alloy Steel Fittings
GradeCMnP maxS maxSiCrMoNiCuOthers
WPB
(1,2,3,4,5)
0.30
max
0.29-1.060.0500.0580.10
min
0.40
max
0.15
max
0.40
max
0.40
max
V 0.08
max
WPC
(2,3,4,5)
0.35
max
0.29-1.060.0500.0580.10
min
0.40
max
0.15
max
0.40
max
0.40
max
V 0.08
max
WP10.28
max
0.30-0.900.0450.0450.10-0.500.44-0.65
WP12 CL10.05-
0.20
0.30-0.800.0450.0450.60
max
0.80-1.250.44-0.65
WP12 CL20.05-
0.20
0.30-0.800.0450.0450.60
max
0.80-1.250.44-0.65
WP11 CL10.05-
0.15
0.30-0.600.0300.0300.50-1.001.00-1.500.44-0.65
WP11 CL20.05-
0.20
0.30-0.800.0400.0400.50-1.001.00-1.500.44-0.65
WP11 CL30.05-
0.20
0.30-0.800.0400.0400.50-1.001.00-1.500.44-0.65
WP22 CL10.05-
0.15
0.30-0.600.0400.0400.50
max
1.90-2.600.87-1.13
WP22 CL30.05-
0.15
0.30-0.600.0400.0400.50
max
1.90-2.600.87-1.13
WP5 CL10.15
max
0.30-0.600.0400.0300.50
max
4.0-6.00.44-0.65
WP5 CL30.15
max
0.30-0.600.0400.0300.50
max
4.0-6.00.44-0.65
WP9 CL10.15
max
0.30-0.600.0300.0301.00
max
8.0-10.00.90-1.10
WP9 CL30.15
max
0.30-0.600.0300.0301.00
max
8.0-10.00.90-1.10
WPR0.20
max
0.40-1.060.0450.0501.60-
2.24
0.75-1.25
WP910.08-
0.12
0.30-0.600.0200.0100.20-0.508.0-9.50.85-1.050.40
max
V 0.18- 0.25
Nb 0.06-0.10
N 0.03-0.07
Al 0.02 max(6)
Ti 0.01 max(6)
Zr 0.01 max(6)
WP9110.09-
0.13
0.30-0.600.0200.0100.10-0.508.0-9.50.90-1.100.40
max
V 0.18-0.25
Nb 0.060-0.10
N 0.04-0.09
Al 0.02 max(6)
B 0.0003-0.006
W 0.90-1.10
Ti 0.01 max(6)
Zr 0.01 max(6)

Notes:

  1. Fittings from bar or plate 0.35 max carbon.
  2. Fittings from forgings 0.35 max Carbon and 0.35 max Silicon with no minimum.
  3. For each reduction of 0.01% below the specified Carbon maximum, an increase of 0.06% Manganese above the specified maximum is permitted, up to a maximum of 1.35%.
  4. The sum of Cu, Ni, Niobium, and Moly shall not exceed 1.00%.
  5. The sum of Niobium and Moly shall not exceed 0.32%.
  6. Applies to heat and product analyses

ASTM A234 Mechanical Properties

Tensile and Yield Strength ASTM A234 for Carbon and Alloy Steel FittingsWPBWPC,
WP11-CL2
WP11-CL1,
WP22-CL1
WP5-CL1
WP9-CL1
WP11-CL3,
WP22-CL3
WP5-CL3
WP9-CL3
WP91
Tensile strength, minimum unless a range is given ksi (MPa)60 (415)70 (485)60 (415)75 (520)90 (620)
Yield strength, min ksi (MPa) (0.2% offset or 0.5% extension under-load)35 (240)40 (275)30 (205)45 (310)60 (415)
Elongation ASTM A234 for Carbon and Alloy Steel FittingsWPB,
WPC, WP11, WP22
WP91
 Longitud.TransverseLongitud.Transverse
Standard
round specimen, or small proportional specimen, min % in 4 D
22142013
Rectangular specimen for wall thickness 5/16″ and over, and
for all small sizes tested in full section; min % in 2 in.
3020
Rectangular specimen for wall thickness less than 5/16″;
min % in 2 in (1/2″ wide specimen)
see note

Note:  For each 0.79 mm decrease in wall thickness below 7.94 mm, a deduction of 1.5 % for longitudinal and 1.0 % for transverse from standard values are permitted

STAINLESS STEEL BUTTWELD FITTINGS (ASTM A403)

The ASTM A403 specification covers austenitic stainless steel butt weld fittings to match ASTM A312 TP304, TP316, TP321, etc., pipes.

Pipe Fittings Materials: ASTM A430 for stainless steel pipe fittings

ASTM A403 Chemical Composition

Show 10202550100 entriesSearch:

GradeUNSCMnPSSiNiCrMoTiNOthers
WPXM-19S209100.064.0-6.00.0450.03111.5-13.520.5-23.51.50-3.00.20-0.40
WP304S30400.0820.0450.0318.0-11.018.0-20.0
WP304LS304030.030
(4)
20.0450.0318.0-12.018.0-20.0
WP304HS304090.04-0.1020.0450.0318.0-11.018.0-20.0
WP304NS304510.0820.0450.0318.0-11.018.0-20.00.10-0.16
WP304LNS304530.0320.0450.0318.0-11.018.0-20.00.10-0.16
WP309S30900.220.0450.03112.0-15.022.0-24.0
WP310SS31080.0820.0450.03119.0-22.024.0-26.0
WPS31254S312540.0210.030.010.817.5-18.519.5-20.56.0-6.50.18-0.22Cu0.50-1.0
WP316S31600.0820.0450.03110.0-14.016.0-18.02.0-3.0
WP316LS316030.030 align=”center”(4)20.0450.03110.0-14.0
(5)
16.0-18.02.0-3.0
WP316HS316090.04-0.1020.0450.03110.0-14.016.0-18.02.0-3.00.10-0.16
WP316NS316510.0820.0450.03110.0-13.016.0-18.02.0-3.00.10-0.16
WP316LNS316530.0320.0450.03110.0-13.016.0-18.02.0-3.00.10-0.16
WP317S31700.0820.0450.03111.0-15.018.0-20.03.0-4.0
WP317LS317030.0320.0450.03111.0-15.018.0-20.03.0-4.0
WPS31725S317250.0320.0450.03113.5-17.518.0-20.04.0-5.00.2
WPS31726S317260.0320.0450.03113.5-17.517.0-20.04.0-5.00.10-0.20
WPS31727S317270.0310.030.03114.5-16.517.5-19.03.8-4.50.15-0.21Cu2.8-4.0
WPS32053S320530.0310.030.01124.0-26.022.0-24.05.0-6.00.17-0.22

Showing 1 to 20 of 29 entriesPreviousNext

Notes:

  1. Maximum, if not otherwise indicated.
  2. The method of analysis for Nitrogen is agreed between the purchaser and manufacturer.
  3. Niobium 0.10-0.30%; Vanadium, 0.10-0.30%.
  4. For small diameter or thin walls, a Carbon maximum of 0.040% is mandatory in grades TP304L and TP316L. Small outside diameter tubes are those less than 0.50 in. [12.7 mm] 5) in outside diameter and light wall tubes as those less than 0.049 in. [1.24 mm] in average wall thickness.
  5. On pierced tubing, the Nickel maybe 11.0-16.0%.
  6. 5 X (C+N2)-0.70.
  7. 4 X (C+N2) -0.70.
  8. The Niobium % shall be ten times above the Carbon content and not more than 1.10%.
  9. The Niobium % shall be eight times above the Carbon content and not more than 1.10%.

ASTM A403 Mechanical Properties

Tensile and Elongation Requirements ASTM A403WP304, WP316WP304L, WP316L
Yield Strength, min, ksi [MPa]30 [205]25 [170]
Tensile Strength, min, ksi [MPa]75 [515]70 [485]
ElongationLongitudinal2828
Transverse2020

DUPLEX/ SUPER DUPLEX BUTTWELD FITTINGS (ASTM A815)

The ASTM A815 specification covers duplex and super duplex butt weld fittings to match ASTM A790 and ASTM A928 pipes. These special grades of stainless steel are used for various chemical processes,  piping, oilfield piping and heat exchangers, flue gas desulfurization processes.

Pipe Fittings Materials: ASTM A815 for Duplex and Superduplex Pipe Fittings

Duplex stainless steel has the following advantages over Series 300 standard SS: 

  • Good general corrosion resistance and high strength
  • Higher resistance to chloride stress corrosion cracking
  • Resistance to chloride pitting and crevice corrosion
  • Good sulfide stress corrosion resistance
  • Easy to weld and conform

UNS S31803, UNS S32205 Chemical Composition (Duplex)

GradeCMnSiPSCrMoNiNFe
S318030.030 max2.00 max1.00 max0.030 max0.020 max22.0 – 23.03.0 – 3.54.50 – 6.500.14 – 0.2063.72 min
S322050.030 max2.00 max1.00 max0.030 max0.020 max21.0 – 23.02.50 – 3.504.50 – 6.500.8 – 0.2063.54 min

UNS S31803, UNS S32205 Mechanical Properties (Duplex)

GradesDensity (g/cm 3)Density (lb/in 3)Melting Point (°C)Melting Point (°F)
S31803 / S322057.8050.2851420 – 14652588 – 2669

UNS S32750, UNS S32760 Chemical Composition (Super Duplex)

GradeCMnSiPSCrMoNiNFe
S 327500.030 max1.20 max0.80 max0.035 max0.020 max24.00 – 26.003.00 – 5.006.00 – 8.000.24 – 0.3258.095 min
S 327600.05 max1.00 max1.00 max0.030 max0.010 max24.00 – 26.003.00 – 4.006.00 – 8.000.20 – 0.3057.61 min

UNS S32750, UNS S32760 Mechanical Properties (Super Duplex)

GradesDensity (g/cm 3)Density (lb/in 3)Melting Point (°C)Melting Point (°F)
S32750 / S327607.80.28113502460

NICKEL ALLOY BUTTWELD FITTINGS (ASTM B366)

Nickel alloy buttweld fittings are used for higher pressure/temperature and corrosive media, where lower grades would fail. The ASTM B366/SB 366 specification covers these high-alloy grades buttweld fittings (super-alloys) as Inconel, Incoloy, Hastelloy and the others listed in the table below. The MSS-SP 43 specification, instead, covers the dimensions and the tolerances of nickel alloy buttweld fittings.

Nickel-Alloy Buttweld Fittings Grades

NameUNSDINMatching Pipe GradeEquivalent Forged Grade
904LN089041.4539B677/B673B649
Alloy 020N080202.466B729/B464B462
Alloy 230N06230B622/B619B564
Alloy 400 (Monel)N044002.436B165/B725B564
Alloy 59N060592.4605B622/B619B564
Alloy 600 (Inconel)N066002.4816B167/B517B564
Alloy 625 (Inconel)N066252.4856B444/B705B564
Alloy 800 (Incoloy)N088001.4558B407/B514B564
Alloy 800H (Incoloy)N088101.4958B407/B514B564
Alloy 800HT (Incoloy)N088111.4959B407B564
Alloy 825 (Incoloy)N088252.4858B423/B705B564
Alloy BN10001B622/B619
Alloy B2 (Hastelloy)N106652.4617B622/B619
Alloy B3 (Hastelloy)N10675B622/B619B564
Alloy C22 (Hastelloy)N060222.4602B622/B619B564
Alloy C276 (Hastelloy)N102762.4819B622/B619B564
Alloy C4N064552.461B622/B619
Alloy G-3N069852.4619B622/B619
Alloy G30N06030B622/B619
Alloy K500 (Monel)N055002.4375B865
Nickel 200N022002.4066B161/B725B564
Nickel 201N022012.4068B161/B725

Nickel-Alloy Buttweld Fittings Chemical Composition

Show 10202550100 entriesSearch:

 FeCNiCrMoCoCuMnSSiWVPAlTi
Nickel 200.40 max.15 max99.0 min.25 max.35 max.01 max.35 max
Nickel 201.40 max.02 max99.0 min.25 max.35 max.01 max.35 max
Hastelloy C2764.0-7.0.01 maxRemainder14.5-16.515.0-17.02.5 max1.0 max.03 max.08 max3.0-4.5.35 max.04 max
Inconel 6006.0-10.0.15 max72.0 min*14.0-17.0.50 max1.00 max.015 max.50 max
Inconel 601140.0561.522.50.30.21.4
Inconel 6255.0 max.10 maxRemainder20.00-30.008.0-10.01.0 max**.50 max.015 max.50 max.015 max.40 max.40 max
Inconel 718Remainder.08 max50.00-55.0017.00-21.002.80-3.301.00 max.30 max.35 max.015 max.35 max.015 max.20-.80.65-1.15
Incoloy 80039.5 min.10 max30.0-35.019.0-23.0.15-.60.15-.60
Incoloy 800H39.5 min.05-.1030.0-35.019.0-23.0.15-.60.15-.60
Incoloy 800HT39.5 min.06-.1030.0-35.019.0-23.0.25-.60.25-.60
Incoloy 82522.0 min0.05 max38.0-46.019.5-23.51.5-3.01.0 max0.03 max0.5 max0.2 max.6-1.2
Alloy 20Balance.07max32.00-38.0019.0-21.02.0-3.03.0-4.02.0max.035max1.0max.045max
Monel K5002.0 max.25 max63.0-70.0Remainder1.5 max.01 max.50 max2.30-3.15.35-.85

Showing 1 to 13 of 13 entriesPreviousNext

Typical Applications for Nickel Alloy Materials (Oil & Gas)

Nickel AlloyTypical Application Area in Oil & Gas Engineering
Nickel 200/201Marine and offshore engineeringCaustic handling equipmentManufacture and handling of sodium hydroxideReactors and vessels where fluorine reacts with hydrocarbons
Hastelloy C-276Pollution control stack liners, ducts, dampers, scrubbers, stack-gas reheaters, fans, and fan housingsFlue gas desulfurization systemsChemical processing components like heat exchangers, reaction vessels, evaporators, and transfer pipingSour gas wells
Monel K500Sour-gas service applicationsOil and gas production safety lifts and valvesOil-well tools and instruments like drill collarsOil well industryChains, cables, springs, valve trim, fasteners for marine service
Monel 400Marine engineeringChemical and hydrocarbon processing equipmentGasoline and freshwater tanksCrude petroleum stillsDe-aerating heatersBoiler feed water heaters and other heat exchangersValves, pumps, shafts, fittings, and fastenersIndustrial heat exchangersChlorinated solventsCrude oil distillation towers
Incoloy 800H/HTEthylene furnace quench boilersHydrocarbon crackingValves, fittings and other components exposed to corrosive attack from 1100-1800° FIndustrial furnacesHeat-treating equipmentChemical and petrochemical processingSuper-heater and re-heaters in power plantsPressure vesselsHeat exchangers
Incoloy 825Chemical ProcessingPollution-controlOil and gas well pipingNuclear fuel reprocessingComponents in Pickling equipment like heating coils, tanks, baskets and chainsAcid production
Inconel 600Chemical industryHeat treating industryNuclear EngineeringGas turbine components
Inconel 601Chemical ProcessingAerospaceHeat treating industryPower generationHeat treating muffles and retortsRadiant tubesCatalyst support grids in nitric acid productionSteam superheater tube supports
Inconel 625Specialized seawater equipmentChemical process equipment
Inconel 718Chemical processingPollution-control equipmentNuclear reactorsCryogenic storage tanksValves, fasteners, springs, mandrels, tubing hangersWellhead completion equipment and blow out preventers (BOPS)

COATED, LINED AND CLAD FITTINGS

In some cases, buttweld fittings can be externally coated with protective materials, internally lined (example PTFE may be inserted to enhance the resistance of the bare metal to corrosive fluids) or clad (the picture shows a clad tee: the tee is made of carbon steel, but the inner side is covered by a higher grade material, stainless steel 316 in this case).

Example of clad tee

EUROPEAN VS ASTM BUTTWELD FITTINGS MATERIALS

The table shows the equivalent ASTM and European pipe fittings materials grades.

Butt Weld Fittings Materials Comparison Chart
Werkstoff NumberEuropean GradeASTM Grade
CARBON STEEL FITTINGS MATERIALS
1.0254 St 37.0S235
– –
1.0305 St 35.8/IP235GH (1.0345)A 234 Grade WPA
1.0305 St 35.8/IIIP235GH (1.0345)
1.0405 St 45.8/IP265GH (1.0425)A 234 Grade WPB
1.0405 St 45.8/IIIP265GH (1.0425)
ALLOY STEEL FITTINGS MATERIALS
1.5415 15 Mo 316Mo3A 234 Grade WP1
1.7335 13 CrMo 4 413CrMo4-5A 234 Grade WP11, WP12
1.7380 10 CrMo 9 1010CrMo9-10A 234 Grade WP22
1.7362 12 CrMo 19 5X11CrMo5A 234 Grade WP5
– –A 234 Grade WP9
1.4903  –X10CrMoVNb9-1A 234 Grade WP91
LOW-TEMPERATURE CARBON STEEL FITTINGS MATERIALS
1.5637 10 Ni 1412Ni14A 420 Grade WPL3
1.0356 TTSt 35 NP215NL (1.0451)
1.0356 TTSt 35 V
– –A 420 Grade WPL6
HIGH YIELD CARBON STEEL FITTINGS MATERIALS
– –
1.0486 StE 285A860 Grade WPHY42
1.0562 StE 355P355NA860 Grade WPHY52
1.8902 StE 420A860 Grade WPHY60
1.8905 StE 460A860 Grade WPHY70
HIGH YIELD CARBON STEEL FITTINGS MATERIALS
1.0457 StE 240.7
1.0484 StE 290.7L290NBA860 Grade WPHY42
1.0582 StE 360.7L360NBA860 Grade WPHY52
1.8972 StE 415.7L415NBA860 Grade WPHY60
– –
STAINLESS STEEL FITTINGS MATERIALS
1.4541 X 6 CrNiTi 18 10X6CrNiTi18-10A 403 Grade WP321
1.4571 X 6 CrNiMoTi 17 12 2X6CrNiMoTi17-12-2A 403 Grade WP316Ti
1.4301 X 5 CrNi 18 10X5CrNi18-10A 403 Grade WP304
1.4306 X 2 CrNi 19 11X2CrNi19-11A 403 Grade WP304L
1.4307  –X2CrNi18-9A 403 Grade WP304L
1.4401 X 5 CrNiMo 17 12 2X5CrNiMo17-12-2A 403 Grade WP316
1.4404 X 2 CrNiMo 17 13 2X2CrNiMo17-12-2A 403 Grade WP316L
1.4462 X 2 CrNiMoN 22 5 3X2CrNiMoN22-5-3UNS S 31803 (Duplex)
1.4529 X 1 NiCrMoCuN 25 20 6X1NiCrMoCuN25-20-7UNS N 08926
1.4539 X 1 NiCrMoCuN 25 20 5X1NiCrMoCu25-20-5UNS N 08904 (904L)
1.4547  –X1CrNiMoCuN20-18-7UNS S 31254