3.1B Seamless Alloy Steel Pipe , Hot Finished Seamless Tube 1-120mm Thickness

What is the different of 3.1B seamless Steel Pipe certificates with 3.2 seamless alloy pipes

Seamless Steel Pipe Specific testing
 Specific Test Report (manufacturer) – manufacturer’s test certificate, test results based on specific testing.

This is only issued if the manufacturer has no independent testingstation.

If the testing station is independent, in lieu of this certificate a Certificate 3.1.B has to be issued.
3.1.A Inspection Certificate 3.1.A (office inspector)
3.1.B Inspection Certificate 3.1.B (works inspector)
3.1.C Inspection Certificate 3.1.C (purchase inspector)
3.2 Inspection Report 3.2 (works and purchase inspector

What is the hot finished seamless tubes production process