大变形X80管线钢的应变时效简

 大变形管线钢是一种管道在通过地质复杂地区(滑坡、地震、冻土等)时，为了降低地层移动对管道可能造成的变形损伤而开发出来的新型管道结构用材料。采用材料显微分析方法和力学性能测试等手段，对一种大变形X80管线钢在应变时效中的脆化规律进行了研究。结果表明，应变时效使试验钢产生脆化。随着应变时效温度的升高，强度和硬度增加，塑性和韧性下降。应变时效脆化形成的机制是管线钢间隙原子与位错的交互作用。与普通X80钢相比，大变形X80钢的应变时效倾向较小,这是因为双相组织中铁素体固溶的碳、氮原子少，位错密度低。

Strain Aging of X80 Pipeline Steel With Excellent Deformability

The pipeline steel with the excellent deformability is a new type pipe structure material. for preventing the any pipe fracture due to plastic deformation by ground movement (such as earthquakes, landslides or permafrost region, etc) based on the strain-based design theory. The strain-aging embrittlement behavior of X80 pipeline steels with excellent deformability (PSED) was investigated by microscopic analysis and mechanical properties testing. The results indicated that strain-aging can induce the embrittlement behavior of X80 pipeline steel. Both strength and hardness of the PSED can be increased with the aging temperature, while ductility and toughness will be decreased. The strain-aging embrittlement mechanism of pipeline steel is the interaction of interstitial and dislocation. The strain-aging tendency of PSED is lower than that of ordinary X80 pipeline steel. The probable reason is the lower solution of carbon and nitrogen atoms, and the lower dislocation density in ferrite phase of dual-phase microstructure.