石油化工管式炉铬钼钢焊接回弯头技术标准(附条文说明)石油化工管式炉铬钼钢焊接回弯头技术标准(附条文说明)Technical standard for chrome-molybdenum alloy steel plug-welding return of petrochemical tubular heater
石油化工管式炉碳钢和铬钼钢炉管焊接技术条件(附条文说明)
Technical specification for welding of carbon steel and chrome-molybdenum alloy steel tube of tubular heater in petrochemical industry