Difference Between A671 and A672 EFW Pipes

A671 and A672 areEFW (Electric-Fusion Welded) Carbon Steel Pipes used for atmospheric and lower temperatures applications (A671) and high-pressure service at moderate temperatures (A672). As mentioned above, A671 is used for atmospheric and lower temperature application and A672 is used for high-pressure service applications at moderate temperature. However, if we compare the details e.g. A672 Gr.C60 & A671 Gr. CC60; the raw material plate used is same for both pipes & final mechanical properties are same. Heat treatment is same. The only difference between the 2 grades is only in the testing requirements. A672 requires weld sample drawn from a 500ft length of pipe and allows you to double the samples in case, original sample fails. A671 requires weld sample drawn from a 200ft length of pipe with no provision for a rejected weld.

Understanding difference in different grades

We come across different grades amongst A671 and A672 categories like CA/CB/CC (signified the type of plate used) and also different classes like CL 12/22/32 etc. We will attempt to explain these differences in the below table with simplified classification.

The above classification should simplify any confusion with respect to different grades and classification. Apart from these, there are other classes like CL 10, CL13 and C42. The differences in due to Radiography and Test Pressure, for eh CL 10 does not need radiography as well as the pressure test, CL 13 does not need radiography but required Test Pressure, CL 42 needs the plate to be normalized as well as tempered with Radiography Testing and Test Pressure.