This specification is intended to cover several "low hydrogen" types of arc welding electrodes of various alloys for elevated temperature service and for corrosion resistance. The designation "low hydrogen" applies to electrodes having coverings which are substantially free from water and other compounds such as cellulose which will liberate hydrogen in the arc. Intended use of each type is as specified in 6.1.1 through 6.1.6.

Type MIL-80XX-B2 is intended for welding 1-¼ percent chromium, ½ percent molybdenum steel in high temperature service up to 950°F.

Type MIL-90XX-B3 is intended for the welding of 2-¼ percent chromium, 1 percent molybdenum steel in high temperature service up to 1050°F involving moderate conditions of corrosion or oxidation.

Type MIL-410-XX is intended for the welding of 12 percent chromium steel in service up to 1300°F where very good resistance to corrosion and oxidation is required. Where strength is a factor, it is seldom used above 1200°F.

Type MIL-502-XX is intended for the welding of 5 percent chromium, ½ percent molybdenum steel in high temperature service up to 1200°F involving severe corrosive or oxidizing conditions.

Type MIL-505-XX is intended for the welding of 9 percent chromium, 1-¼ percent molybdenum steel in high temperature service up to 1300°F involving severe corrosive and oxidizing conditions. This alloy has good oxidation resistance up to 1500°F.

The L type electrode is intended for use in welding materials of the same composition that the respective higher carbon type is used. L types may be used where preheat and interpass temperature control is impractical, where the base material is 1 inch thick or less. The L types also may be used on heavier than 1 inch base material with preheat and interpass temperature control 100°F to 200°F below that required for the respective higher carbon types. The L types may also be used on base material less than 1 inch in thickness when post heat is impractical.