Pipes, fittings, and flanges manufactured according to ASTM standards have a chemical composition determined by percentages of the permitted quantities of carbon, magnesium, nickel, etc., as shown by “Grade”.

It is possible to identify carbon steel pipes by Grade A or B, stainless steel pipes by Grade TP304 or Grade TP321, and carbon steel fittings by Grade WPB, for example.

As one of the leading manufacturers of Alloy Steel Pipe Fittings in India, Aesteiron Steels LLP is an excellent choice. Our company manufactures pipe fittings including reducers, caps, elbows, tees, bends, couplings, unions, and nipples.

Welding Buttweld Fittings in Alloy Steel:

This types of metal fittings pipe allows the direction of flow to be changed, the pipe size to be reduced or auxiliary equipment to be attached. The fittings are permanently leak proof because of its many inherent advantages. This system is reinforced by the continuous metal structure that forms between the fitting and pipe. Corrosion and erosion are minimized through smooth inner surfaces and gradual direction changes, which reduce pressure losses and turbulence. Despite being ferrous, it is still susceptible to rust when exposed to the elements.

Alloy Steel Weld Fittings:

It refers to the process of inserting a pipe into recessed areas of valves, fittings, or flanges. For piping with a nominal diameter of NPS 2 or smaller, it is primarily used for small pipe diameters. Stainless steel has a tensile strength of 758-1882 MPa, whereas carbon steel has a strength of 758-1882 MPa.

Low Alloy Steel Fittings 

In general, alloys with a total content of 1.5% to 5% are considered to be alloys. It is alloyed with chromium, manganese, silicon, molybdenum, nickel, vanadium, and molybdenum. Heating elements are manufactured with it.

Elbows made of alloy steel

Flow direction is changed by this component in a piping system. The pipe can be turned in a 45-degree or 90-degree angle by connecting two pipes with different or same nominal diameters.

 Tee made from alloy steel

Fluid can be changed direction by three branches. Liquids and gases are commonly conveyed through pipe networks. There are two outlets in T-shape, at 90° to this line’s connection. A lateral outlet is located at the end of a short pipe piece. A wide variety of elbow seamless pipe fittings are made from it.

The following are three tables with chemical requirements for

  • Flanges ASTM A182 Grade F304, F304L F316L
  • Pipes ASTM A312 Grade TP304, TP304L, TP3016L
  • Fittings ASTM A403 Grade WP304, WP304L, WP316L

Moreover, there is a table that shows the most commonly used ASTM grades for a234 Pipes, Fittings, Flanges, Valve, Bolt, and Nuts that are all related.

You may have noticed that ASTM A105 does not have a grade in the table below. It is sometimes described as ASTM A105N;

N stands for normalized, not grade. In view of the fact that normalizing is a type of heat treatment, it is important to note that it can only be applied to ferrous metals. Normalizing an object, as the term implies, is the process of removing the internal stresses that have been produced by heat treatment, casting, forming, etc., in order to make the object as normal as possible.

What is Steel pipe fittings

A steel pipe fitting material like , plate, profile, or device made of carbon or alloy fitting  steel that is shaped in a way that could change the flow direction or rate of fluid in a pipeline system. Most of these fittings include steel elbows for pipe (45 or 90 degree bends), tees, reducers (concentric or eccentric reducers), caps, nipples, flanges, gaskets, and studs.

For industrial applications, pipeline systems require changes in transmission direction, fluid flow rate adjustment, opening and closing of pipelines, etc. This will be accomplished by using steel pipe fittings.

What is ASTM A234 WPB

This standard is an ASTM A234 which specifies the 3r elbow dimensions and a234 materials of steel elbow for pipe fittings for moderate and high-temperature applications ranging from mild steel to alloy steel. The scope of the document covers both seamless and welded steel fittings. There are many uses for steel pipe fittings, including pressure pipelines and pressure vessels that are fabricated from steel. The material that makes up these fittings is comprised of steel, forgings, bars, plates, seamless or HFW (fusion welded) pipe products, as well as filler metal that has been added to them.

Among the fittings covered by ASTM A234 are wrought carbon steel fittings of seamless and welded construction, that meet ASTM B16.9, B16.11, MSS-SP-79, MSS-SP-83, MSS-SP-95, and MSS-SP-97. etc.

In pressure piping and pressure vessel fabrication, ASTM A234 steel pipe fittings are used for moderate and elevated temperatures. This standard specifies materials for fittings such as killed steel, forgings, bars, plates, and seamless or fusion-welded tubular products.

There are specifications for elbows, tees, reducers, caps, and crosses in this standard. The ends are usually butt welded.

Grades in ASTM A234

Various grades of ASTM A234 are available, including WPB, WPC, WP5, WP9, WP11, WP12, WP22, and WP91.

For medium and high temperature pipelines, WPB is the most common material. The W indicates weldability, the P indicates pressure, and the B indicates minimum yield strength.

WPB steel pipe fittings, as per ASTM A234 WPB, may be manufactured from steel pipe, including ASTM A106 Gr.B. It may also be manufactured from steel plate, such as ASTM A285 Gr.C, ASTM A516 Gr 70, ASTM A572.

ASTM A234 WPB steel pipe fitting charts : chemical and mechanical features

A maximum of 0.35 percent C can be obtained for Grade WPB fittings made from steel pipes or plates.

No minimum carbon or silicon content for forged fittings. Maximum carbon and silicon content 0.35%.

Manganese maximum content increases by 0.06% for every 0.01 reduction in Carbon content, up to a maximum of 1.35% for Mn.

It is not permitted to exceed 1.00% in the sum of copper, nickel, niobium,, and molybdenum.

It is prohibited to exceed 0.32% Niobium + Molybdenum.


ASTM Materials


  1. A106▸ Covers high-temperature carbon steel pipe.
  2. A335▸ Ferritic alloy-steel seamless pipes for high temperatures are covered by this specification.
  3. A333▸ Carbon and alloy steel seamless and welded pipes intended for low temperature service are covered by this specification.
  4. A312▸ Stainless steel pipe for high-temperature and general corrosive applications that cannot be welded using any type of welding process, whether seamless, straight-seam welded, or cold worked welded.


  1. A234▸ Fittings comprised of seamless and welded carbon steel and alloy steel are covered by this standard.
  2. A420▸ Mechanical specifications for low-temperature alloy steel and wrought carbon steel fittings.
  3. A403▸ An international standard for wrought austenitic stainless steel pipe fittings.


  1. A105▸ It is a standard for forged carbon steel piping components, such as flanges, fittings, valves, and similar parts, designed for use in pressure systems at ambient pressure and higher temperature ranges.
  2. A182▸ Contains specifications for high-temperature pipes, fittings, valves, and parts made from forged or rolled alloy and stainless steel.
  3. A350▸ Flanges, fittings, and valves made of carbon and low alloy steel are covered under this specification.


  1. A216▸ This specification covers castings made from carbon steel for valves or flanges, fittings, or other pressure-containing parts for high temperatures and suitable for welding to other castings or wrought-steel parts.
  2. A217▸ This specification covers castings of steel, martensitic stainless steel,, and alloy steel designed to withstand high temperatures and corrosion.
  3. A352▸ Specifically applicable to undertension valves, flanges, fittings, and other pressure-containing parts intended for extremely low temperatures.
  4. A182▸ This specification covers pipe flanges and fittings for alloys and stainless steels, valves, and parts for high temperatures.

Bolts and Nuts

  1. A193▸ Describes bolting materials for high temperature, high-pressure, or special purpose applications, including pressure vessels, valves, and flanges.
  2. A320▸ Specification for Low-Temperature Bolting Materials in Alloy Steel and Stainless Steel.
  3. A194▸ Specifies nuts made of various materials.

What are alloy steel pipe fittings?

There are a variety of alloys used in alloy steel pipe fittings. A fitting’s corrosion resistance and properties are determined by the alloy content. An alloy with a higher alloying element has better properties. A primary alloy of iron and carbon is used in the fittings of this grade.

What is ASTM A234 WPB?

 ASTM A234 specifies steel pipe fittings for moderate and high temperature applications made from carbon and alloy steel. Fittings made of steel that are seamless or welded are included. In the fabrication of pressure vessels and pipelines, steel pipe elbows fittings are used.

What is Buttweld pipe fittings?

A buttweld fitting allows pipe flow to be changed directions, branched off, reduced in size or attached to auxiliary equipment. Buttweld fittings made of forged steel comply with ANSI / ASME B16 specifications.

What does ASTM a105 mean?

Forged piping components made from carbon steel satisfy ASTM A 105, an ASTM steel forging specification. Forging of carbon steel alloy is similar to AISI 1330 in that it contains low carbon, manganese, and silicon, although AISI 1330 has less manganese than this type of carbon steel alloy.

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