In plumbing systems, pipe fittings attach one pipe to another. The purpose of these forged fittings is to lengthen, support, or change the direction flow of a plumbing system carrying any type of fluid or fluidized product. Forged pipe fittings allow the highest strength connections for safety and reliability.

Stainless steel forged fittings are more durable than plain iron or carbon steel fittings, providing resistance to rust and corrosion. Forged fittings are subject to thermal and mechanical processes that not only change the product shape but refine and improve the metallurgy, all forging achieved in a solid state.

Forged stainless steel has:

  • High impact toughness
  • Improved wear resistance
  • Directional material flow to provide added strength
  • Fine grained structure for best fatigue properties

Many types of forged fittings are available, so it is important to understand their differences that contribute to project success. When creating piping systems for critical applications requiring stainless steel pipe fittings, the ASTM A182 and ASME SA182 are the most used standards in the USA and many other countries.

Stainless Steel Forged Fittings Dimensions

While it is possible to find standard stainless-steel forged fittings in a range of sizes, shapes, and compositions, there are times when the standard components are not sufficient. When specially made fittings are needed that can exceed the standards or allow unique construction, QC Forge can assist in forging design. The dimensions of forged stainless-steel fittings determine flow capacity and pressure. When you find the standards do not supply the specific need for small components, QC Forge is ready to help.

Standard fittings are built to handle 2,000, 3,000, 6,000, or 9,000 PSI (13.8 MPa, 20.7 MPa, 41.4 MPa, 62 MPa). Diameters range from .125 (3.175mm) inch to 4 inches (101.6mm). Pipe fittings are typically threaded or configured for socked or butt welding.

Typical fitting shapes are:

  • Elbows with varying degrees of bend angle
  • Crosses – plain and reducing
  • Tees – plain and reducing
  • Couplings – generally for joining lengths of pipe
  • Unions – to create joints that can be opened.
  • And many special configurations to accommodate unique designs

The required shape configuration of a particular stainless-steel forged fitting depends upon the service it must perform in the system. A specific sensor of other equipment may require an unusual connection that does not appear in any catalogue or standard product line.

Stainless Steel Forged Fittings Tolerances

The American Society of Mechanical Engineers (ASME) sets and controls the standards for forged stainless steel pipe fittings. The two standards most applied to forged pipe fittings are ASME B16.9 and ASME B16.11.

The B16.9 standard covers butt-welded fittings and short radius returns and elbows. For factory-made butt-welded fittings, the standard covers acceptable:

  • Dimensions
  • Ratings
  • Testing
  • Tolerances
  • Markings

When a unique product is to be forged, these standards become the reference to be used in design to assure compatibility with all standard products with which the custom items are to be used.

Stainless Steel Forged Fittings Chemistry

As outlined in ASTM A182 and ASME SA182, exposing components to different chemical environments require different compositions of stainless-steel to assure safe and reliable performance. Certain grades are more suitable for welding to avoid subsequent cracks or other defects that can emerge with time at service. Other grades provide less corrosion resistance but higher strength. The chemical composition of every alloy is adjusted to meet specific service requirements. Understanding those requirements can lead to the optimum material selection.

The grades of stainless steel generally differ by the amount of Iron, Chromium, Nickel, Copper, and Molybdenum, but additional added elements and processing techniques provide a wide range of grades and capabilities.

For more discussion on chemical composition, types of stainless-steel and stainless steel fittings, please see our entry at Stainless Steel Forged Fittings.