X70钢热煨弯管用母管采购验收技术问题探讨

On the Technical Problems of Procurement and Acceptance of X70 Steel for Fire Bending Bent Pipes

X70钢热煨弯管用母管的性能指标是采购该母管的重要验收依据。从热煨弯管母管化学成分、制管工艺、焊接工艺及母管机械性能及尺寸等方面,探讨X70钢热煨弯管用母管采购验收时应考虑的技术问题。在热煨弯管用母管采购过程中要求:化学成分(含钒、钼、铬等合金元素)及碳当量控制合适;母管机械性能高于弯管要求的5%以上;母管管体的壁厚偏差处于上偏差;母管管体外径精度不超过3mm;焊接材料采用Mn-Ni-Mo-Ti-B合金系焊丝。

The performance index of the mother pipe for X70 Steel fire bending bent pipe was important basis for acceptance of procurement of the mother pipe.From the aspects of chemical composition,manufacturing process,welding process,mechanical property of the mother pipe and size of the fire bending bent pipe,the technical problems of the fire bending bent pipe acceptance were discussed.During the procurement of X70 Steel fire bending bent pipe,it is required that the chemical composition(containing vanadium,nickel and chrome) and carbon equivalent should be proper,the mechanical performance of mother pipe should be more than 5% higher than that required for the bent pipe,the error of mother pipe thickness should be at up limit,the precision of outside diameter of mother pipe should be within 3mm,Mn-Ni-Mo-Ti-B alloy should be used for welding.