A691 EFW Pipe Supplier India — ASTM A691 (from A387 Plate)

ASTM A691 is an Electric Fusion Welded (EFW) steel pipe specification for high-temperature, high-pressure service. A691 pipe is manufactured by forming ASTM A387 (or A516) alloy/carbon steel plate into a cylindrical shape and welding the longitudinal seam using submerged arc welding (SAW). The pipe then undergoes full heat treatment (normalising + tempering) and the weld seam receives 100% radiographic examination (RT) per ASME Section V. A691 is used where seamless pipe is unavailable in large diameters — typically 16 inch to 60 inch — making it essential for power plant headers, large-diameter crossover piping and refinery transfer lines.

A691 is an EFW (welded) pipe made from plate, while A335 is a seamless pipe made by piercing solid billets. A691 is used for large diameters (16 inch to 60 inch) where seamless pipe is either unavailable or prohibitively expensive. A335 seamless pipe is preferred for sizes up to 24 inch due to no weld seam and inherently better integrity. For A691, the weld seam must be 100% RT examined and the pipe PWHT'd after welding. The base plate (A387) chemistry and properties are identical — the difference is solely the manufacturing method. A691 pipe grade designation corresponds to its source plate: 1.25CR = A387 Gr.11, 2.25CR = A387 Gr.22.

Creative Metal Industries supplies ASTM A691 EFW pipe in diameters from 16 inches (400NB) to 60 inches (1500NB) in various wall thicknesses from 12mm to 100mm depending on the design pressure and temperature. Standard grades include 1.25CR (from A387 Gr.11 plate), 2.25CR (from A387 Gr.22 plate), 5CR (from A387 Gr.5 plate) and CMSH-70 (from A516 Gr.70 plate). Pipe lengths typically 6-12 metres. For common sizes like 16 inch-36" in 1.25CR and 2.25CR, we maintain ready stock. Larger sizes and 9CR grade are available on 8-12 week mill delivery.

ASTM A691 pipe undergoes rigorous testing and inspection: 100% radiographic examination (RT) of the longitudinal weld seam per ASME Section V; hydrostatic test at pressure per ASTM A691 formula; tensile testing of base metal and weld seam (transverse tensile across weld); guided bend tests (face and root bends) on weld specimens; Charpy impact testing at specified temperature (if supplementary requirement S1 is invoked); hardness testing on base metal, weld metal and HAZ; and full dimensional inspection. The pipe manufacturer must hold ASME U-stamp or equivalent pressure vessel fabrication certification.

In thermal power plants, A691 EFW pipe is used wherever large-diameter Cr-Mo piping is required: boiler outlet headers (24 inch-36" dia) connecting superheater tube banks to main steam lines; HP/IP crossover pipes connecting HP turbine exhaust to reheater inlet; cold reheat lines (large diameter, moderate temperature); HRSG manifolds and headers in combined cycle plants; and attemperator bypass piping. The most common grades for power plant service are 1.25CR (for intermediate-temperature headers at 480-540°C) and 2.25CR (for main steam headers at 540-565°C in subcritical plants).

Yes, we supply ASTM A691 EFW pipe with IBR Form III-C certification for boiler and pressure piping applications in India. The IBR certification covers both the source plate (A387 with IBR) and the pipe fabrication (welding procedure qualified per IBR requirements, RT of weld seam witnessed by IBR inspector). Our A691 suppliers are IBR-approved fabricators with full ASME and IBR certification. Documentation includes plate MTC (original A387 certificate), welding procedure qualification records (WPQR), RT film reader sheets, hardness survey reports, heat treatment records and IBR Form III-C for the finished pipe.