Weld Mold 938 description: Weld Mold 938 is an exceptional high alloy product for repair welding of high carbon and/or high chrome varieties of air hardening tool steels. Weld deposits are homogeneous, porosity-free and completely heat treatable. For use on all D2 air hardening steel and for upgrading the A Series as well as a buildup overlay on the lower grades of steel. For cold working shears, blanking and forming dies, punches, slitter knives, trimmers, and other units that demand high performance. 938 is also used for composite fabrication on other types of lower alloy steel.