TMCP工艺对X70管线钢在酸性环境中织构和抗氢脆性能的影响

为研究热机械轧制（TMCP）工艺对X70管线钢抗氢脆性能的影响，采用两种不同的TMCP工艺参数改变钢的组织和织构，并通过电化学充氢和氢渗透试验，研究了织构和微观结构对X70管线钢抗氢致开裂（HIC）性能的影响。结果表明，TMCP并没有改变钢板的物相，不同TMCP参数的钢板均由针状铁素体、多边形铁素体及少量珠光体组成，且大多分布在晶界周围；增加氢浓度会使位错周围产生氢气氛并锁定位错，使改变塑性变形所需的应力增大，导致硬化。研究表明，冷却速率能够影响晶粒尺寸，冷却速度越高，晶粒尺寸越小，较多的精轧道次和较快的冷却速率会增加钢中可逆陷阱的数量，促使发生HIC。

Effect of TMCP Process on Texture and Hydrogen Embrittlement Resistance of X70 Pipeline Steel in Acidic Environment

In order to study the effect of thermo-mechanical controlled process(TMCP) on hydrogen embrittlement resistance of X70 pipeline steel, two different processes parameters were used to change the microstructure and texture of steel. The effects of texture and microstructure on hydrogen induced cracking(HIC) resistance of X70 pipeline steel were studied by electrochemical hydrogen charging and hydrogen permeation tests. The results showed that TMCP did not change the phase of the plate. Plates with different TMPC parameters are composed of acicular ferrite, polygonal ferrite and a small amount of pearlite, and are mostly distributed around the grain boundary. Increasing hydrogen concentration will generate hydrogen atmosphere around the dislocation and lock the dislocation. Therefore, the stress required to change plastic deformation increases, resulting in hardening. The result shows that the cooling rate is another factor affecting the grain size. The higher the cooling rate is, the smaller the grain size is. The results show that more finishing passes and faster cooling rate will increase the number of reversible traps in the steel and promote the occurrence of HIC.