What is CMSH-70?

CMSH-70 stands for Carbon-Manganese-Silicon High strength with the 70 representing 70,000 psi minimum tensile strength. It is part of the ASTM A691 standard of electric fusion-welded pipes designed for high-pressure service.

The silicon content makes this grade different from standard carbon steel. Most carbon steel grades have low silicon, just enough to deoxidise the steel during manufacturing. In CMSH-70, the silicon level is higher on purpose. It strengthens the ferrite phase in steel. You get better tensile and yield strength without adding chromium or molybdenum.

This keeps the price low compared to alloy grades while still meeting the strength needs of high-pressure piping systems. The downside, however, is that CMSH-70 is that it doesn't resist oxidation at high temperatures as well as chrome-moly grades do. It works best in environments where strength is more important than high-temperature performance.

Specification of ASTM A691 CMSH-70 IBR Pipe

Following are the key specifications for our A691 CMSH-70 pipes that cover standard, grades, type and more:

Standard ASTM A691 / ASME SA691
Types Seamless / ERW / Welded / Fabricated / LSAW Pipes
Pipes Size 1/2” NB to 36” NB
Thickness 0.3mm – 12 mm
End Plain End, Beveled End, Treaded

IBR Certification

IBR stands for Indian Boiler Regulations. Any pressure part going into a boiler in India needs IBR approval. This is not optional. The regulation exists to prevent boiler accidents. Our CMSH-70 pipes come with IBR Form III-C certification. This confirms that the material meets all IBR requirements. The testing is done by Government-approved laboratories. Each pipe carries proper identification and traceability. Without IBR certification, you cannot use the pipe in boiler services in India. We take care of the documentation and ship it with your order.

Applications of CMSH-70 pipe

CMSH-70 is used in applications where you need high strength at moderate temperatures:

Power Plants

Thermal power stations use large-diameter piping to transport steam and water around the plant. The main headers, crossover piping and high-pressure feedwater lines need materials that can handle the pressure without excessive wall thickness. In this case, CMSH-70 works well. As it is stronger, it can have thinner walls than regular carbon steel. It offers benefits like less weight, easier handling during construction, and lower material costs per meter of pipe.