耐硫化氢腐蚀X80管线钢轧制工艺的模拟优化

摘要

Thermal expansion instrument was used to study the phase transition behaviors of hydrogen sulfide corrosion resistant X80 pipeline steel during continuous cooling and continuous cooling transformation (CCT)curves were drawn.Moreover,simulation test for its rolling process was also carried out using thermal simulation test machine.And the effects of deformation temperature,cooling rate and coiling temperature on microstructure and hardness of tested steel were analyzed,and the optimized rolling process parameters were obtained.At last,for the tested steel rolled at optimized rolling process parameters,its mechanical properties and hydrogen induced cracking (HIC)resistance were tested.The results demonstrat that phase change temperature of the tested steel mainly occurred between 450 ℃ and 780 ℃.With the increase of cooling rate, the phase transformation starting temperature was overall declined.In addition,the microstructure was mainly acicular ferrite when the cooling rate was between 1.76 ℃.s-1 and 8.8 ℃.s-1 .The optimum rolling process parameters was determined as phase transition temperature,cooling rate and coiling temperature of (830±15)℃,15 ℃.s-1 and (400±15)℃, respectively.The tested steel rolled at the above rolling process parameters had good HIC resistance,and it can meet strength demands of API5L on X80 pipeline steel.%采用热膨胀仪研究了耐硫化氢腐蚀X80管线钢在连续冷却过程中的相变行为，绘制了其连续冷却转变曲线(CCT曲线)；并且利用热模拟试验机对其轧制工艺进行模拟，研究了变形温度、冷却速率和卷取温度对试验钢组织和硬度的影响，得到了较优化的轧制工艺；最后测试了在优化轧制工艺参数下轧制试验钢的力学性能和抗氢致开裂性能.结果表明：试验钢的相变温度主要发生在450~780℃之间；随着冷却速率增加，相变开始温度下降，并且当冷速为1．76~8．8℃.s－1时可以得到以针状铁素体为主的组织；最佳的轧制工艺参数为变形温度(830±15)℃、冷却速率15℃.s－1、卷取温度为(400±15)℃；在此工艺参数下轧制得到的试验钢具有优良的抗氢致开裂性能，并可以满足API5L标准对X80管线钢强度级别的要求.