ASTM Grades of Steel

A672 is a specification that covers steel pipe (electric-fusion welded with filler metal added), fabricated from pressure-vessel quality plate of any of several analyses and strength levels suitable for high-pressure service at moderate temperature.

I have posted the table from the standard identifying the pipe grades of A672 to which plate material it was formed from:

The additional numbers and letters (A, B, C,......... 50, 55, 60, ..........) identify different grades within a specification based on composition, properties, and strength.

The numbers generally correlate to minimum specified tensile strength.

thanks for ur answer.may i know which book is this and from where i will get it?

That came directly from the standard, available for purchase here:

http://www.astm.org/Standards/A672.htm

Is A672-A55 can be used on a pipeline designed using ASME B31.3. service fluid is ethylene and operating pressure is 46 bar and temp is 55C.

Yes, A672-A55 is allowed with B31.3

What is the equivalent of s355 in astm