API 5ST pdf download Specification for Coiled Tubing U.S. Customary and SI Units Surface macrohardness shall also be measured on the surfaces of skelp-end and tube-to-tube welds. The hardness values shall comply with the requirements given in Table A.2. By agreement, and when specified on the purchase agreement, additional macro- or microhardness tests shall be taken at specified locations. 6.2.3...