离心铸造双金属复合管缺陷及控制

Manufacturing Defects and Control of Centrifugal Casting Double Metal Composite Pipe

介绍了碳钢/镍基合金双金属复合管的生产工艺及其金相组织和化学成分,对离心浇注、热挤压、热处理等过程出现的缺陷进行分析。结果表明,转速控制在950~1 050r/min之间,管坯厚度不均匀性大为降低,而裂纹缺陷基本消除;热挤压时,在加热温度为1 180℃,模具预热温度为460℃、挤压力为35 MN、挤压速度为65 mm/s、挤压比为6.4、采用进口专用玻璃粉润滑剂,可避免复合管内表面凹坑和裂纹;在910℃×90min处理后油冷,然后在650℃×150min空冷后所得复合管力学性能满足技术要求。

Production process,microstructure and chemical composition of the double metal composite pipe were introduced,and defects in the double-metal composite pipe were analyzed during centrifugal casting,hot extrusion,heat treatment process.The results reveal that by controlling rotary velocity in950~1 050 r/min,thick-heterogeneity of pipe-blank is decreased greatly,and crack is basically eliminated.Concave and crack in inner surface of composite pipe can be eliminated with heating at 1 180℃and preheating mold at 460 ℃ as well as squeezing force of 35 MN,squeezing velocity of 65 mm/s,squeezing ratio of 6.4 and the imported special glass powder lubricant.With quenching at 910 ℃ for 90 min and oil cooling＋tempering at 650℃for 150 min and air cooling,mechanical properties of the composite pipe can meet technological requirement.