The chemical composition of submerged arc welded or electric welded pipe should meet the requirements of Appendix I, Section A2.0.
For welded pipe products, the steelmaking practice should require "inclusion shape control" chemistry additions to avoid Type II Mn inclusions and silicate stringers in the finish product. Supplier should include a brief description of steelmaking practices with his quotation.
2.0 Mechanical Properties and Tests
For seamless pipe in grades of X-60 and higher, hardness tests should be taken on one quadrant on a ring sample from each 25 joints or one per heat, whichever is greater. Hardness traverses should be made at a distance of 1-2 millimeters from the O.D. and I.D. surfaces and at mid-wall. A Rockwell or Vickers test should be performed. The maximum hardness value should be HRC 22. If any hardness test fails, the pipe should be rejected and one retest should be taken on two other pipes from the heat in the lot that failed. If either or both tests fail, the entire heat should be rejected or reprocessed. If both tests pass, the entire heat may be accepted.
For welded submerged arc welded or electric welded pipe, one metallographic cross section of the weld should be cut from each pipe from which tensile test samples are cut. Each traverse should include readings at less than 1.0 millimeters intervals in the base metal, HAZ, and weld metal (at least 3 readings in each zone) on both sides of the weld. No values should exceed 250 VHN using a 10 kg load. If any hardness test fails, the pipe should be rejected and one retest should be taken on two other pipes from the heat in the lot that failed. If either or both tests fail, the entire heat should be rejected or reprocessed. If both tests pass, the entire heat may be accepted.
Unless waived by Buyer, a HIC test per NACE TM02-84 Solution A should be performed on one pipe of each of the first three heats produced, and then every tenth heat in sequence thereafter. The test results should meet the following requirements: