Content Summary

 

 BUTT WELD, FORGED AND TUBE FITTINGS

 PIPE AND TUBE FITTINGS

Pipe and pipe fittings are very close products that are deployed together to implement a pipeline with a specific layout and flow line. A pipe fitting changes the direction of the pipeline (or of a tubing arrangement), branches it, increases or decreases the run pipe diameter or closes the oil & gas pipeline. Carbon steel pipe fittings are used for non aggressive media which generate low corrosion rates, whereas stainless steel pipe fittings (or nickel alloy pipe fittings, such as Inconel, Incoloy, Hastelloy, Alloy 20 and Cupronickel fittings) are used when the pipeline is subject to strong corrosion (example H2SO4 fluid, i.e. Sulphuric acid) or operates at high temperatures and pressures (bar / psi / PN). Stainless precision pipe fittings are also widely adopted for instrumentation systems.

 FITTINGS AND PIPE CONNECTION METHODS

Pipe fittings can be joined with steel tubes and pipes by multiple types of connections: the most common are butt weld and socket weld connections (in this case the fitting is welded on the pipe), threaded connections (the pipe or the tube is connected by screwing the fitting onto the pipe, and grooved connections (such as the Victaulic system). Butt weld ends are generally used for pipeworks above 2", whereas socket weld ends and threaded ends are used for small diameter / small bore pipelines (pipeline below 2").

 PIPE AND TUBE FITTINGS TYPES

There are few different types of pipe and steel tube fittings, the main categories are:

 BUTT WELD FITTINGS

Butt weld fittings are available in numerous shapes (butt weld elbows, tees, reducers, crosses, etc) and their dimensions are aligned to those of the connecting pipes (NPS and pipe schedules for ASTM butt weld fittings, OD and WT in mm for EN bw fittings).

The ends of all butt weld fittings are beveled, and the shape of the bevel depends upon the actual wall thickness. The ASME B16.25 Norm determines the preparation of the butt weld ends of piping components to be joined by welding operations. This norm includes requirements for bevels, for the external and internal shape of heavy-wall components, and for the preparation of the internal ends (including dimensions and dimensional tolerances). These weld edge preparation requirements are also referred to into other ASME standards (e.g., B16.9, B16.5, B16.34). The dimensions and tolerances of carbon and alloy steel butt weld fittings are defined by the ASME B16.9 standards, while light weight corrosion resistant fittings in stainless steel or nickel alloy steel are manufactured according to MSS SP43.

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 BUTT WELD ELBOW

Butt weld elbow ASME B16.9

There are few different types and shapes of elbows: 45-degree elbow LR (long radius), 90-degree elbow LR (long radius), 180-degree elbow LR (long radius), 90-degree elbow SR (short radius), 180-degree elbow SR (short radius). Elbows are split into two groups (LR and SR) based upon the distance over which they change in direction. The "center to face" distance is equivalent to the radius through which the elbow is bent. The center to face distance for an LR elbow is always 1.1/2 x Nominal Pipe Size (NPS) (1.1/2D), whereas the center to face distance for a "short" radius elbow, abbreviated SR is even to the nominal pipe size. The radius of a 45° elbow is the same as the radius of the 90° LR (1.1/2D). Nevertheless, the center to face dimension is not the same as in 90° LR elbows. Short radius 45° elbows do not exist. ASME B16.9 defines the dimensions, tolerances, etc. for long and short radius elbows. The weakest point of elbows is the inside radius. ASME B16.9 standardizes only the center to face dimensions and some dimensional tolerances. The wall thickness at the weld line location even is standardized, but not through the rest of an elbow. The standard states that the min. the tolerance shall be within 12.5% of the ordered wall thickness of the pipe. A maximum tolerance is specified only at the ends of the fitting.

Reducing elbows are elbows with different diameters on the two ends. To contain costs, the use of a standard elbow in conjunction with a butt weld reducer may be an alternative to reducing elbows (which are generally costly and have long lead times). Other types of elbows are the 3D / 5D elbows (i.e elbows with center to face dimension three to five times the nominal size).

 BUTT WELD TEE

Butt weld tee ASME B16.9

The scope of a butt weld tee is to make a 90° branch from the main run of the pipeline. Tee are available in the equal or reducing versions. The equal tee (or straight tee) is used if the branched pipe has the same diameter as the run-pipe. The reducing tee is used whenever the branched pipe has a smaller diameter when compared to the run pipe. Reducing tee are available in standardized combinations (of course any reduction ratio is possible, at extra cost generally).

 BUTT WELD REDUCER

ASME B16.9 concentric eccentric reducer

Reducers are used to decrease or increase the pipeline size at a certain point of its route; there are on the market concentric reducers and eccentric reducers (concentric reducers are generally used in vertical pipelines; eccentric reducers are instead generally used in horizontal pipelines). It maybe interesting to note that the overall length of a reducer is generally very short while the reduction in diameter may be remarkable (for example, a reducer NPS 8 - NPS 4 has a length of 160 mm, but the pipeline diameter would be reduced significantly): piping engineers shall take such consideration into account to prevent possible design and performance problems of the pipeline, generated by the sudden change of flow capacity.

 BUTT WELD CAP

Butt weld cap ASME B16.9

As the name evocates, butt weld caps are used to close a pipeline.

 STUB END

ASME B16.9 stub end

A stub end is always used in connection with a lap joint flange, as a backing flange. Such arrangement is used for low-pressure and non critical applications and may be considered as a cheap option to realize a flanged joint or flanged connection in a pipeline. In a stainless steel pipe system, for instance, a carbon steel flange can be used as a backing flange since it will not come into contact with the pipeline media, thus saving the cost of an un necessary stainless steel flange. Stub Ends are available in almost all pipe diameters. Dimensions and dimensional tolerances are defined by the ASME B.16.9 Norm. Light-weight corrosion resistant stainless steel stub ends are manufactured in accordance to the MSS SP43 Norm.

Butt weld fittings are advantageous for the following reasons:

  • Welding a pipe with a fitting ensures a permanent leak proof connection
  • The seamless metal structure formed between pipe and fitting generates a very strong system
  • The smooth inner surface reduces potential pressure losses as well as turbulence and minimize the action of erosion and corrosion

Generally known manufactures of butt weld fittings are Allied fittings, Erne Fittings, Interfit, TK Bend, SK Bend, Benkan.

 FORGED FITTINGS

Forged fittings are used in small diameter piping system (NPS below 2’’) and are manufactured out of forged steel. Forged fittings are available with socket weld ends or, alternatively, threaded ends. Similarly to butt weld fittings, forged fittings are used to create a specific layout of the pipeline. Forged fittings may be grouped in the following macro categories:

ASME B16.11 forged elbow

SOCKET WELD AND THREADED FITTINGS: 45-90 degree elbows, tees, laterals, street elbows.

Forged plugs and bushing

PLUGS AND BUSHINGS: Round head caps, square head caps, hexagonal head caps, flush bushings and hexagon bushings.

Forged couplings

COUPLING REDUCERS AND CAPS: Half / full couplings, reducers, caps, reducer inserts type 1 and 2.

Forged unions

UNIONS: Rockwood unions, MSS SP 83 unions, lug nut unions.

Welding boss

WELDING BOSSES: Threaded and socket weld welding bosses.

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 CONNECTION TYPES: SOCKET WELD (SW) AND THREADED (THD)

Forged steel fittings may be connected to pipes and tubes by means of threaded or socket weld connections:

THREADED CONNECTIONS

Threaded connections are one of the oldest ways of joining piping systems which is utilized in low cost and uncritical applications such as domestic water, fire protection, and industrial cooling water systems. A good leakage performance can be achieved for low-pressure, low-temperature installations where vibration is not an issue. However, rapid temperature changes may lead to leaks due to differential thermal expansion between the pipe and fittings. The tapered pipe threads dimensional standards are provided in ASME B1.20.1 together with all the required dimensions including number of threads per inch, pitch diameter, and normal engagement lengths by pipe diameters. Threaded fittings are normally manufactured out of cast gray or malleable iron, cast brass or bronze, or forged alloy and carbon steel. Threaded fittings are available in classes 2000, 3000 and 6000 according to ANSI B16.11. In the case of hazardous installations, threaded connections should be avoided, if possible. Their vulnerability to fatigue damage is significant, especially where exposed threads are subject to corrosion.

SOCKET WELD CONNECTIONS

A socket weld end requires a fillet-type seal weld to join the pipe to the fitting. Socket-welded is the optimal choice wherever the benefits of high leakage integrity and great structural strength are key. The resistance to fatigue is lower than that in butt-welded construction, but it is still superior to other mechanical joining methods. Socket weld fittings are a family of high-pressure fittings and are used in various industrial processes.

Socket weld fittings are generally used:

  • for lines conveying flammable, toxic or expensive material where no leakage can be permitted, and for steam 300 to 600 PSI
  • in conjunction with ASME pipes
  • for permanent pipe work installations
  • SW (socket weld) fittings are produced in accordance to the ASME B16.11 Norm and are available in a multitude of ASTM materials. This norm covers the pressure and temperature ratings, dimensions, tolerances, marking, and material requirements for forged carbon and alloy steel fittings. Acceptable material forms are forgings, bars, seamless pipe, and seamless tubes which conform to the fittings chemical requirements, melting practices, and mechanical property requirements of ASTM A105, A182, or A350. They are available in three pressure ratings: Class 3000, 6000 and 9000.

The main advantages of socket weld fittings are:

  • The pipe need not be beveled for weld preparation
  • The fitting ensures proper alignment for the welding
  • The weld metal can not penetrate the pipe
  • Smaller leakage than threaded fittings
  • Radiography is not easy to execute on the fillet weld and a correct fitting and welding is crucial for good leakage performance
  • Construction costs are lower than butt-welded joints since there is no need for special machining for butt weld end preparation.

 BRANCH CONNECTIONS (O'LETS)

Branch fittings (also referred to as “O'lets”) provide specific types of connections between pipes of similar or different diameter. The main pipe onto which the branch connection is welded is usually denominated “run pipe”. The pipe to which the branch connection provides a channel is usually called “branched pipe”. Branch connections are manufactured in a wide range of sizes, types, bores, classes and material grades (carbon steel, stainless steel, alloy steel, nickel alloys steels such as Inconel 600, Inconel 625, Incoloy 800, Hastelloy C276, Alloy 20, etc.). The main types of branch connections are:

Weldolet

WELDOLET: Weldolets are branch connections welded onto the outlet pipe. The ends of a Weldolet are beveled. Weldolets are designed to minimize stress concentration and provide a good reinforcement to a branched connection.

Sockolet
SOCKOLET: Sockolets are pipe branches connected by means of a socket weld. The bore matches the bore of the outlet, and the existence of a counter bore roughly the size of the OD of the outlet provides a socket where the pipe can sit, thus facilitating the installation and welding.
Threadolet

THREADOLET: Thredolets are connected to run pipes by a thread just inside the top of the o’let. The bore is of the same size of the outlet bore, and the threading facilitates installation since no welding activity is required.

Latrolet

LATROLET: Latrolets are used for 45° lateral connections and are available either butt-weld to meet specific reinforcement requirements or in 3000# or 6000# in case of socket weld and threaded connection.

Elbolet

ELBOLET: Elboles are used on 90° LR / SR elbows generally for instrumentation connections and are available either butt-weld to meet specific reinforcement requirements or in 3000# or 6000# in case of socket weld and threaded connection.

Nipolet

NIPOLET: Nipolets are a one piece fitting used for valve take offs, drains and vents that are manufactured for XS and XXS applications in lengths of 3.1/2in to 6.1/2in. Nipolets are available with male socket weld or male threaded outlets.

Sweepolet

SWEEPOLET: Sweepolets are a contour and reinforced butt-weld branch connection designed for long fatigue duty. The connecting weld can be radiographed, tested with ultrasounds, and other standard nondestructive tests.

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 COMPRESSION FITTINGS AND PRECISION FITTINGS

Twin ferrule compression fittings (otherwise called double ferrule compression fittings, or simply compression fittings) and precision pipe fittings are widely used in the petrochemical and oil & gas industries to implement instrumentation systems.

Twin Ferrule

COMPRESSION FITTINGS: These fittings are available in the single or double ferrule configuration and are used to connect instrumentation tubing. Compression fittings are installed where occasional disassembly or partial removal for maintenance may be necessary as these joints can open and closed several times. Compression fittings are composed of an outer compression nut and an inner compression ferrule made of brass or copper. When the nut is serrated, the ferrule gets compressed between the nut and the fitting; the ends of the ferrule get clamped around the pipe, and the middle of the ferrule inclines away from the pipe, thus making the ferrule thicker. Hence the ferrule seals the space between the pipe, nut and receiving fitting, and forms a tight joint. It is critical to avoid an excessive tightening of the nut otherwise the integrity of the fitting gets impacted. When the nut is too tightened, the ferrule is subject to deformation and the joint does not perform as intended resulting in possible leakage. A good approach is to tighten the nut at first manually and then tighten it an additional one half-turn using a wrench.

Compression fittings are typically available in metric (metric to fractional) or fractional (fractional to fractional) sizes.

Twin ferrule fittings can be grouped into the following key categories:

  • Connectors (male connector, female connector, bulkhead male connector, bulkhead female connector, butt weld pipe connector, socket weld tube connectors)
  • Male and female elbows
  • End closures (tube, fitting)
  • Reducers
  • Tees (male run tee, female run tee, male branch tees, female branch tees)
  • Unions

Compression fittings are very common within the chemical, oil and gas and power generation industries and used for the leak proof performance they ensure. Compression fittings do not need welding activities, nor require any special tool or skill to be installed. Hence, they are quick and easy to be deployed on field. Compression fittings can perform at high pressures and with toxic media.

Precision

PRECISION FITTINGS: In addition to single and double ferrule compression fittings, stainless steel precision pipe fittings find wide application within the petrochemical, oil & gas and power generation industry and are widely used to implement instrumentation systems.

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 PIPE AND TUBE FITTINGS DIMENSIONS

FITTING TYPE NPS (Nominal Pipes Size): SCH /  Rating
BUTT WELD FITTINGS
(Butt weld fittings are generally available in the same NPS and SCH of pipes)
Seamless butt weld fittings: 1/8” – 24”
Welded butt weld fittings: generally for NPS > 24”
SCH 5, 10, 20, 30, 40, 60, 80, 100, 120, 140, 160, STD, XS and XXS (carbon steel, alloy steel pipe)
Schedule 5S thru 80S (stainless steel, nickel steel pipe)
FORGED FITTINGS Forged fittings: up to 4”
O’lets (branch connections): up to 24”
Socket weld: Class 3000, 6000, 9000
Threaded fittings: 2000, 3000, 6000
COMPRESSION FITTINGS Fractional: 1 1/16” – 1 ½”
Metric: 3-50
N/A
FITTING TYPE REFERENCE NORM
BUTT WELD FITTINGS ASME B16.9 (carbon / alloy) / ASME B16.28 / ASME B16.49 / MSS SP43 (stainless and nickel alloys)

The ASME B16.9 Standard covers the tolerances, markings, dimensions, ratings, and testing for wrought carbon and alloy steel factory made butt weld fittings between NPS 1/2 and 48 inches. It covers fittings of any available wall thickness.
The ASME B16.25 norm covers the execution of butt weld ends of piping components that are joined into a piping system by welding. It includes the requirements for the external and internal shaping of heavy-wall components, the bevels, and for set up of the internal ends (including dimensions and dimensional tolerances).
The ASME B16.49 Norm covers the manufacturing, marking, design, material, testing, and inspection requirements for factory made bends of carbon steel materials having controlled chemistry and mechanical properties, produced by the induction bending process, with or without tangents. This standard covers induction bends for transportation and distribution piping applications (e.g., ASME B31.4, B31.8, and B31.11).
FORGED FITTINGS ASME B16.11: This Standard covers material requirements, ratings, dimensions, dimensional tolerances and marking for socket welded and threaded forged fittings for small size pipelines (below 2”). Such fittings are available in as Classes 2000, 3000, and 6000 (threaded ends) and Class 3000, 6000, and 9000 for socket weld ends.
The ASME B1.20.1 Standard covers the dimensions and gauging of pipe threads for general purpose applications. ASME B1.20.1 is a revision and designation of the previous ANSI B2.1 initially issued in 1968.
NIPPLES ASME B36.10M
SWAGE NIPPLES BS 3799
UNIONS MSS SP 83
REDUCER INSERTS MSS SP 79
COMPRESSION FITTINGS ASME B 31.3, ASME B 1.20.1, BS 4368 Part IV 1984

DIMENSION & WEIGHTS BUTT WELD FITTINGS ASME B16.9 DIMENSION & WEIGHTS BUTT WELD FITTINGS ASME B16.9

DIMENSION & WEIGHTS FORGED FITTINGS ASME B16.11 DIMENSION & WEIGHTS FORGED FITTINGS ASME B16.11

 P&ID SYMBOLS FITTINGS

P&ID SYMBOLS FITTINGS

 PIPE AND TUBE FITTINGS MATERIAL GRADES

Key standards applicable to pipe and tube fittings:

Carbon steel pipe fittings: ASTM specifications

  • A105 Specification for Carbon Steel Forgings for Piping Applications
  • A181 Specification for Carbon Steel Forgings, for General-Purpose Piping
  • A234 Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
  • A350 Specification for Carbon and Low-Alloy Steel Forgings, Requiring Notch Toughness Testing for Piping Components
  • A420 Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service
  • A694 Specification for Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and Parts for High-Pressure Transmission Service

Alloy steel pipe fittings: ASTM specifications

  • A182 Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service
  • A234 Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
  • A350 Specification for Carbon and Low-Alloy Steel Forgings, Requiring Notch Toughness Testing for Piping Components
  • A420 Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service
  • A694 Specification for Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and Parts for High-Pressure Transmission Service

Stainless steel pipe fittings: ASTM specifications

  • A182 Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service
  • A403 Specification for Wrought Austenitic Stainless Steel Piping Fittings

Nickel and nickel alloy pipe fittings: ASTM specifications

  • B160 Specification for Nickel Rod and Bar
  • B164 Specification for Nickel-Copper Alloy Rod, Bar, and Wire
  • B166 Specification for Nickel-Chromium-Iron Alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, and N06045) and Nickel-Chromium-Cobalt-Molybdenum Alloy (UNS N06617) Rod, Bar, and Wire
  • B366 Specification for Factory-Made Wrought Nickel and Nickel Alloy Fittings
  • B462 Specification for Forged or Rolled UNS N06030, UNS N06022, UNS N06035, UNS N06200, UNS N06059, UNS N06686, UNS N08020, UNS N08024, UNS N08026, UNS N08367, UNS N10276, UNS N10665, UNS N10675, UNS N10629, UNS N08031, UNS *N06045, UNS N06025, and UNS R20033 Al
  • B564 Specification for Nickel Alloy Forgings

Copper and copper alloy pipe fittings: ASTM specifications

  • B21 Specification for Naval Brass Rod, Bar, and Shapes
  • B98 Specification for Copper-Silicon Alloy Rod, Bar and Shapes
  • B150 Specification for Aluminum Bronze Rod, Bar, and Shapes

Aluminium and aluminium alloy pipe fittings: ASTM specifications

  • B247 Specification for Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
  • B361 Specification for Factory-Made Wrought Aluminum and Aluminum-Alloy Welding Fittings

Titanium and titanium alloy pipe fittings: ASTM specifications

  • B381 Specification for Titanium and Titanium Alloy Forgings

 KEY MATERIAL GRADES FOR BUTT WELD FITTINGS:

FITTING CARBON STEEL PIPE FITTINGS, ALLOY STEEL PIPE FITTINGS STAINLESS STEEL PIPE FITTINGS, NICKEL ALLOY PIPE FITTINGS
BUTT WELD FITTINGS ASTM A 234 WPB, ASTM A 234 WPC, ASTM A 234 WP1, ASTM A 234 WP5, ASTM A 234 WP9, ASTM A 234 WP11 Cl. 1, ASTM A 234 WP12, ASTM A 234 WP22 Cl. 1, ASTM A 234 WP91, ASTM A 234 WP92, ASTM A420 WPL3, ASTM A420 WPL6, ASTM A420 WPL9, ASTM A 860 WPHY42, ASTM A 860 WPHY52, ASTM A 860 WPHY60, ASTM A 860 WPHY65, ASTM A 860 WPHY70 ASTM A 403 WP304, ASTM A 403 WP304H, ASTM A 403 WP304L, ASTM A 403 WP316, ASTM A 403 WP316H, ASTM A 403 WP316L, ASTM A 403 WP317, ASTM A 403 WP321, ASTM A 403 WP347, ASTM A 403 WP904L, ASTM A 790 UNS S31803 S32205 (duplex), ASTM A 790 UNS S32750 S32760 (Superduplex), ASTM B 363 WPT2 (Titanium Gr. 2), ASTM B 366 Incoloy 825, ASTM B 366 Inconel 625, ASTM B 366 WPHB Hastelloy B, ASTM B 366 WPHB-2 Hastelloy B2, ASTM B 366 WPHC 276 Hastelloy C 276, ASTM B 366 WPHC 4 Hastelloy C4, ASTM B 366 WPN Nickel 200, ASTM B 366 WPNC Monel 400, ASTM B 366 WPNCI Inconel 600, ASTM B 366 WPNIC Incoloy 800, ASTM B 366 WPNL Nickel 201
FORGED FITTINGS / COMPRESSION FITTINGS ASTM A105, ASTM A108, ASTM A266 Gr. 2, ASTM A350 Gr. LF1, ASTM A350 Gr. LF2, ASTM A350 Gr. LF3, ASTM A694 Gr. F42, ASTM A694 Gr. F52, ASTM A694 Gr. F56, ASTM A694 Gr. F60, ASTM A694 Gr. F65, ASTM A182 Gr. F1, ASTM A182 Gr. F2, ASTM A182 Gr. F5, ASTM A182 Gr. F9, ASTM A182 Gr. F11 Cl. 2, ASTM A182 Gr. F12 Cl. 2, ASTM A182 Gr. F22 Cl. 3, ASTM A182 Gr. F91 ASTM A182 F304, ASTM A182 F304L, ASTM A182 F304H, ASTM A182 F310, ASTM A182 F316, ASTM A182 F316L, ASTM A182 F316H, ASTM A182 F321, ASTM A182 F347, ASTM A182 Gr. F51 (duplex), ASTM A182 Gr. F53 (Superduplex), ASTM A182 Gr. F55 (Superduplex), ASTM A182 TP904L, ASTM B166 UNS NO6600 (Inconel® 600), ASTM B564 UNS N06625 (Inconel® 625), ASTM B564 UNS N08825 (Incoloy 825), ASTM B425 UNS-NO8800 (Incoloy 800), ASTM B160 UNS N0200 (Nickel 200), ASTM B564 UNS N04400 (Monel® 400), ASTM B564 UNS N10276 (Hastelloy C-276), ASTM B381 Gr. 2 (Titanium)

 PIPING ASTM GRADES (PIPES, BUTT WELD FITTINGS, FORGED FITTINGS, VALVES, BOLTS)

Material Pipes BW Fittings Flanges/Forged Fittings Valves Bolts & Nuts
Carbon Steel A106 Gr A A234 Gr WPA A105 A216 Gr WCB A193 Gr B7
A194 Gr 2H
A106 Gr B A234 Gr WPB A105 A216 Gr WCB
A106 Gr C A234 Gr WPC A105 A216 Gr WCB
Carbon Steel
Alloy
High-Temp
A335 Gr P1 A234 Gr WP1 A182 Gr F1 A217 Gr WC1 A193 Gr B7
A194 Gr 2H
A335 Gr P11 A234 Gr WP11 A182 Gr F11 A217 Gr WC6
A335 Gr P12 A234 Gr WP12 A182 Gr F12 A217 Gr WC6
A335 Gr P22 A234 Gr WP22 A182 Gr F22 A217 Gr WC9
A335 Gr P5 A234 Gr WP5 A182 Gr F5 A217 Gr C5
A335 Gr P9 A234 Gr WP9 A182 Gr F9 A217 Gr C12
Carbon Steel
Alloy
Low-Temp
A333 Gr 6 A420 Gr WPL6 A350 Gr LF2 A352 Gr LCB A320 Gr L7
A194 Gr 7
A333 Gr 3 A420 Gr WPL3 A350 Gr LF3 A352 Gr LC3
Austenitic
StainlessSteel
A312 Gr TP304 A403 Gr WP304 A182 Gr F304 A182 Gr F304 A193 Gr B8
A194 Gr 8
A312 Gr TP316 A403 Gr WP316 A182 Gr F316 A182 Gr F316
A312 Gr TP321 A403 Gr WP321 A182 Gr F321 A182 Gr F321
A312 Gr TP347 A403 Gr WP347 A182 Gr F347 A182 Gr F347
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 CHEMICAL COMPOSITION ASTM A234: PIPE FITTINGS OF WROUGHT CARBON STEEL AND ALLOY STEEL

Composition, %
Grade C Mn P max S max Si Cr Mo Ni Cu Others
WPB
(1,2,3,4,5)
0.30
max
0.29-1.06 0.050 0.058 0.10
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
0.29-1.06 0.050 0.058 0.10
min
0.40
max
0.15
max
0.40
max
0.40
max
V 0.08
max
WP1 0.28
max
0.30-0.90 0.045 0.045 0.10-0.50   0.44-0.65      
WP12 CL1 0.05-
0.20
0.30-0.80 0.045 0.045 0.60
max
0.80-1.25 0.44-0.65      
WP12 CL2 0.05-
0.20
0.30-0.80 0.045 0.045 0.60
max
0.80-1.25 0.44-0.65      
WP11 CL1 0.05-
0.15
0.30-0.60 0.030 0.030 0.50-1.00 1.00-1.50 0.44-0.65      
WP11 CL2 0.05-
0.20
0.30-0.80 0.040 0.040 0.50-1.00 1.00-1.50 0.44-0.65      
WP11 CL3 0.05-
0.20
0.30-0.80 0.040 0.040 0.50-1.00 1.00-1.50 0.44-0.65      
WP22 CL1 0.05-
0.15
0.30-0.60 0.040 0.040 0.50
max
1.90-2.60 0.87-1.13      
WP22 CL3 0.05-
0.15
0.30-0.60 0.040 0.040 0.50
max
1.90-2.60 0.87-1.13      
WP5 CL1 0.15
max
0.30-0.60 0.040 0.030 0.50
max
4.0-6.0 0.44-0.65      
WP5 CL3 0.15
max
0.30-0.60 0.040 0.030 0.50
max
4.0-6.0 0.44-0.65      
WP9 CL1 0.15
max
0.30-0.60 0.030 0.030 1.00
max
8.0-10.0 0.90-1.10      
WP9 CL3 0.15
max
0.30-0.60 0.030 0.030 1.00
max
8.0-10.0 0.90-1.10      
WPR 0.20
max
0.40-1.06 0.045 0.050       1.60-
2.24
0.75-1.25  
WP91 0.08-
0.12
0.30-0.60 0.020 0.010 0.20-0.50 8.0-9.5 0.85-1.05 0.40
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)
WP911 0.09-
0.13
0.30-0.60 0.020 0.010 0.10-0.50 8.0-9.5 0.90-1.10 0.40
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.
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 CHEMICAL COMPOSITION ASTM A403 – WROUGHT AUSTENITIC STAINLESS STEEL PIPING FITTINGS

Composition, %
Grade UNS
nbsp;
C
strong>(1)
Mn
strong>(1)
P
strong>(1)
S
strong>(1)
Si
strong>(1)
Ni Cr Mo Ti N
strong>(2)
Others
WPXM-19 S20910 0.06 4.0-6.0 0.045 0.030 1.0 11.5-13.5 20.5-23.5 1.50-3.0   0.20-0.40 (3)
WP304 S3040 0.08 2.0 0.045 0.030 1.0 8.0-11.0 18.0-20.0        
WP304L S30403 0.030
(4)
2.0 0.045 0.030 1.0 8.0-12.0 18.0-20.0        
WP304H S30409 0.04-0.10 2.0 0.045 0.030 1.0 8.0-11.0 18.0-20.0        
WP304N S30451 0.08 2.0 0.045 0.030 1.0 8.0-11.0 18.0-20.0     0.10-0.16  
WP304LN S30453 0.030 2.0 0.045 0.030 1.0 8.0-11.0 18.0-20.0     0.10-0.16  
WP309 S3090 0.20 2.0 0.045 0.030 1.0 12.0-15.0 22.0-24.0        
WP310S S3108 0.08 2.0 0.045 0.030 1.0 19.0-22.0 24.0-26.0        
WPS31254 S31254 0.020 1.0 0.030 0.010 0.80 17.5-18.5 19.5-20.5 6.0-6.5   0.18-0.22 Cu0.50-1.0
WP316 S3160 0.08 2.0 0.045 0.030 1.0 10.0-14.0 16.0-18.0 2.0-3.0      
WP316L S31603 0.030 align="center"(4) 2.0 0.045 0.030 1.0 10.0-14.0
(5)
16.0-18.0 2.0-3.0      
WP316H S31609 0.04-0.10 2.0 0.045 0.030 1.0 10.0-14.0 16.0-18.0 2.0-3.0   0.10-0.16  
WP316N S31651 0.08 2.0 0.045 0.030 1.0 10.0-13.0 16.0-18.0 2.0-3.0   0.10-0.16  
WP316LN S31653 0.030 2.0 0.045 0.030 1.0 10.0-13.0 16.0-18.0 2.0-3.0   0.10-0.16  
WP317 S3170 0.08 2.0 0.045 0.030 1.0 11.0-15.0 18.0-20.0 3.0-4.0      
WP317L S31703 0.030 2.0 0.045 0.030 1.0 11.0-15.0 18.0-20.0 3.0-4.0      
WPS31725 S31725 0.030 2.0 0.045 0.030 1.0 13.5-17.5 18.0-20.0 4.0-5.0   0.20  
WPS31726 S31726 0.030 2.0 0.045 0.030 1.0 13.5-17.5 17.0-20.0 4.0-5.0   0.10-0.20  
WPS31727 S31727 0.030 1.0 0.030 0.030 1.0 14.5-16.5 17.5-19.0 3.8-4.5   0.15-0.21 Cu2.8-4.0
WPS32053 S32053 0.030 1.0 0.030 0.010 1.0 24.0-26.0 22.0-24.0 5.0-6.0   0.17-0.22  
WP321 S3210 0.08 2.0 0.045 0.030 1.0 9.0-12.0 17.0-19.0   (6)    
WP321H S32109 0.04-0.10 2.0 0.045 0.030 1.0 9.0-12.0 17.0-19.0   (7)    
WPS33228 S33228 0.04-0.08 1.0 0.020 0.015 0.30 31.0-33.0 26.0-28.0       Ce 0.05-0.10 Al 0.025Nb 0.6-0.10
WPS34565 S34565 0.030 5.0-
7.0
0.030 0.010 1.0 16.0-18.0 23.0-25.0 4.0-5.0   0.40-0.60 Nb 0.10
WP347 S3470 0.08 2.0 0.045 0.030 1.0 9.0-12.0 17.0-19.0       (8)
WP347H S34709 0.04-0.10 2.0 0.045 0.030 1.0 9.0-12.0 17.0-19.0       (9)
WP348 S3480 0.08 2.0 0.045 0.030 1.0 9.0-12.0 17.0-19.0       Nb+Ta= 103(C)-1.10Ta 0.10Co 0.20
WP348H S34809 0.04-0.10 2.0 0.045 0.030 1.0 9.0-12.0 17.0-19.0       Nb+Ta= 83(C)-1.10Ta 0.10Co 0.20
WPS38815 S38815 0.030 2.0 0.040 0.020 5.5-
6.5
13.0-17.0 13.0-15.0 0.75-1.50     Cu 0.75-1.50Al 0.30

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 may be 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%.
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 CHEMICAL COMPOSITION ASTM A105 – CARBON STEEL FORGINGS FOR PIPING APPLICATIONS

Composition, %
Element C Mn P S Si Cu Ni Cr Mo V
  0.35 max 0.60-1.05 0.035 max 0.040max 0.10-0.35 0.40max (1) 0.40max (1) 0.30max (1-2) 0.12max (1-2) 0.08max

Notes:

  1. The sum of Cu, Ni, Niobium, Moly and Vanadium shall not exceed 1.00%.
  2. The sum of Niobium and Molybdenum shall not exceed 0.32%.

Note: For each reduction of 0.01% below the specified carbon maximum (0.35%), an increase of 0.06% Manganese above the specified maximum (1.05%) is permitted up to a maximum of 1.35%.

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 CHEMICAL COMPOSITION ASTM A182 - STAINLESS STEEL FORGINGS FOR PIPING APPLICATIONS

Composition, %
Grade C Mn P S Si Ni Cr Mo Nb Ti Others
F304(1) 0.08 2.0 0.045 0.030 1.0 8.0-11.0 18.0-20.0        
F304H 0.04-0.10 2.0 0.045 0.030 1.0 8.0-11.0 18.0-20.0        
F304L(1) 0.030 2.0 0.045 0.030 1.0 8.0-13.0 18.0-20.0        
F304N(2) 0.08 2.0 0.045 0.030 1.0 8.0-10.5 18.0-20.0        
F304LN(2) 0.030 2.0 0.045 0.030 1.0 8.0-10.5 18.0-20.0        
F309H 0.04-0.10 2.0 0.045 0.030 1.0 12.0-15.0 22.0-24.0        
F310 0.25 2.0 0.045 0.030 1.0 19.0-22.0 24.0-26.0        
F310H 0.04-0.10 2.0 0.045 0.030 1.0 19.0-22.0 24.0-26.0        
F310MoLN 0.030 2.0 0.030 0.015 0.40 21.0-23.0 24.0-26.0 2.0-3.0     N 0.10-0.16
F316 0.08 2.0 0.045 0.030 1.0 10.0-14.0 16.0-18.0 2.0-3.0      
F316H 0.04-0.10 2.0 0.045 0.030 1.0 10.0-14.0 16.0-18.0 2.0-3.0      
F316L(1) 0.030 2.0 0.045 0.030 1.0 10.0-15.0 16.0-18.0 2.0-3.0      
F316N(2) 0.08 2.0 0.045 0.030 1.0 11.0-14.0 16.0-18.0 2.0-3.0      
F316LN(2) 0.030 2.0 0.045 0.030 1.0 11.0-14.0 16.0-18.0 2.0-3.0      
F316Ti 0.08 2.0 0.045 0.030 1.0 10.0-14.0 16.0-18.0 2.0-3.0   (3) N 0.10 max
F317 0.08 2.0 0.045 0.030 1.0 11.0-15.0 18.0-20.0 3.0-4.0      
F317L 0.030 2.0 0.045 0.030 1.0 11.0-15.0 18.0-20.0 3.0-4.0      
F321 0.08 2.0 0.045 0.030 1.0 9.0-12.0 17.0-19.0     (4)  
F321H 0.04-0.10 2.0 0.045 0.030 1.0 9.0-12.0 17.0-19.0     (5)  
F347 0.08 2.0 0.045 0.030 1.0 9.0-13.0 17.0-20.0   (6)    
F347H 0.04-0.10 2.0 0.045 0.030 1.0 9.0-13.0 17.0-20.0   (7)    
F348 0.08 2.0 0.045 0.030 1.0 9.0-13.0 17.0-20.0   (6)   Co 0.20
Ta 0.10
F348H 0.04-0.10 2.0 0.045 0.030 1.0 9.0-13.0 17.0-20.0   (7)   Co 0.20
Ta 0.10

Notes:

  1. Grades F304, F304L, F316, and F316L shall have a maximum Nitrogen of 0.10%.
  2. Grades F304N, F316N, F304LN, and F316LN shall have a Nitrogen of 0.10 to 0.16%.
  3. Grade F316Ti shall have a Titanium content five times above the Carbon plus Nitrogen and not more than 0.70%.
  4. Grade F321 shall have a Titanium content five times above the Carbon and not more than 0.70%.
  5. Grade F321H shall have a Titanium content four times above the Carbon and not more than 0.70%.
  6. Grades F347 and F348 shall have a Niobium content ten times above the Carbon and not more than 1.10%.
  7. Grades F347H and F348H shall have a Niobium content above than eight times the Carbon and not more than 1.10%.
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 MATERIAL COMPARISON CHART ASTM / EN BUTT WELD FITTINGS

Buttwelding Fittings
Material number EN ASTM
1.0254 St 37.0 S235 -
- - - -
1.0305 St 35.8/I P235GH (1.0345) A 234 Grade WPA
1.0305 St 35.8/III P235GH (1.0345) -
1.0405 St 45.8/I P265GH (1.0425) A 234 Grade WPB
1.0405 St 45.8/III P265GH (1.0425) -
Alloyed heat-resistant
1.5415 15 Mo 3 16Mo3 A 234 Grade WP1
1.7335 13 CrMo 4 4 13CrMo4-5 A 234 Grade WP11, WP12
1.7380 10 CrMo 9 10 10CrMo9-10 A 234 Grade WP22
1.7362 12 CrMo 19 5 X11CrMo5 A 234 Grade WP5
- - - A 234 Grade WP9
1.4903  - X10CrMoVNb9-1 A 234 Grade WP91
Low temperature
1.5637 10 Ni 14 12Ni14 A 420 Grade WPL3
1.0356 TTSt 35 N P215NL (1.0451) -
1.0356 TTSt 35 V - -
- - - A 420 Grade WPL6
Fine-grain steels
- - - -
1.0486 StE 285 - A 860 Grade WPHY42
1.0562 StE 355 P355N A 860 Grade WPHY52
1.8902 StE 420 - A 860 Grade WPHY60
1.8905 StE 460 - A 860 Grade WPHY70
High yield steels
1.0457 StE 240.7 - -
1.0484 StE 290.7 L290NB A 860 Grade WPHY42
1.0582 StE 360.7 L360NB A 860 Grade WPHY52
1.8972 StE 415.7 L415NB A 860 Grade WPHY60
- - - -
Stainless steel
1.4541 X 6 CrNiTi 18 10 X6CrNiTi18-10 A 403 Grade WP321
1.4571 X 6 CrNiMoTi 17 12 2 X6CrNiMoTi17-12-2 A 403 Grade WP316Ti
1.4301 X 5 CrNi 18 10 X5CrNi18-10 A 403 Grade WP304
1.4306 X 2 CrNi 19 11 X2CrNi19-11 A 403 Grade WP304L
1.4307  - X2CrNi18-9 A 403 Grade WP304L
1.4401 X 5 CrNiMo 17 12 2 X5CrNiMo17-12-2 A 403 Grade WP316
1.4404 X 2 CrNiMo 17 13 2 X2CrNiMo17-12-2 A 403 Grade WP316L
1.4462 X 2 CrNiMoN 22 5 3 X2CrNiMoN22-5-3 UNS S 31803 (Duplex)
1.4529 X 1 NiCrMoCuN 25 20 6 X1NiCrMoCuN25-20-7 UNS N 08926
1.4539 X 1 NiCrMoCuN 25 20 5 X1NiCrMoCu25-20-5 UNS N 08904 (904L)
1.4547  - X1CrNiMoCuN20-18-7 UNS S 31254
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