This study investigated the effect of pressure,pre-charge time,punch velocity and oxygen content on the mechanical properties of X42 pipeline steel in gaseous hydrogen environment by using small punch test.When expose...This study investigated the effect of pressure,pre-charge time,punch velocity and oxygen content on the mechanical properties of X42 pipeline steel in gaseous hydrogen environment by using small punch test.When exposed to nitrogen,the fracture mode of X42 pipeline steel undergoes ductile fracture,but in the presence of hydrogen,it shifts to brittle fracture.Moreover,an increase in hydrogen pressure or a decrease in punch velocity is found to enhance the hydrogen embrittlement susceptibility of X42 pipeline steel,as evidenced by the decrease of maximal load,displacement at failure onset and small punch energy.But the effect of pre-charge time on the hydrogen embrittlement susceptibility of X42 pipeline steel is not very obvious.Meanwhile,the presence of oxygen has been found to effectively inhibit hydrogen embrittlement.As the oxygen content in hydrogen increases,the hydrogen embrittlement susceptibility of X42 pipeline steel decreases.展开更多
选择双椭球热源模型对M42高速钢/X32弹簧钢双金属带锯的电子束焊接的温度场进行Ansys数值模拟,确定焊接的最佳工艺参数,并进行焊接试验,利用扫描电镜观察M42/X32接头的微观组织。结果表明,最佳焊接工艺为焊接电压U=140 k V,焊接电子束电...选择双椭球热源模型对M42高速钢/X32弹簧钢双金属带锯的电子束焊接的温度场进行Ansys数值模拟,确定焊接的最佳工艺参数,并进行焊接试验,利用扫描电镜观察M42/X32接头的微观组织。结果表明,最佳焊接工艺为焊接电压U=140 k V,焊接电子束电流Ib=20 m A,焊接速度v=2 m/min。在此工艺条件下进行电子束焊接实验,焊缝宽度实验值和计算值的相对误差为-3%~1.5%,二者吻合较好,验证了双椭球热源模型在电子束焊接温度场模拟中的适用性。M42/X32接头的焊缝中心为等轴晶和柱状晶的典型铸态组织;M42熔合区（FZ）组织为马氏体和M2C型碳化物,M42热影响区（HAZ）组织为马氏体、残余奥氏体及碳化物。X32熔合区（FZ）由类马氏体层和马氏体组织组成,X32热影响区（HAZ）组织为马氏体、残余奥氏体以及M23C6。展开更多
基金supported by the National Key R&D Program of China(2021YFB4001601)the Youth Innovation Promotion Association CAS(2022187).
文摘This study investigated the effect of pressure,pre-charge time,punch velocity and oxygen content on the mechanical properties of X42 pipeline steel in gaseous hydrogen environment by using small punch test.When exposed to nitrogen,the fracture mode of X42 pipeline steel undergoes ductile fracture,but in the presence of hydrogen,it shifts to brittle fracture.Moreover,an increase in hydrogen pressure or a decrease in punch velocity is found to enhance the hydrogen embrittlement susceptibility of X42 pipeline steel,as evidenced by the decrease of maximal load,displacement at failure onset and small punch energy.But the effect of pre-charge time on the hydrogen embrittlement susceptibility of X42 pipeline steel is not very obvious.Meanwhile,the presence of oxygen has been found to effectively inhibit hydrogen embrittlement.As the oxygen content in hydrogen increases,the hydrogen embrittlement susceptibility of X42 pipeline steel decreases.
文摘选择双椭球热源模型对M42高速钢/X32弹簧钢双金属带锯的电子束焊接的温度场进行Ansys数值模拟,确定焊接的最佳工艺参数,并进行焊接试验,利用扫描电镜观察M42/X32接头的微观组织。结果表明,最佳焊接工艺为焊接电压U=140 k V,焊接电子束电流Ib=20 m A,焊接速度v=2 m/min。在此工艺条件下进行电子束焊接实验,焊缝宽度实验值和计算值的相对误差为-3%~1.5%,二者吻合较好,验证了双椭球热源模型在电子束焊接温度场模拟中的适用性。M42/X32接头的焊缝中心为等轴晶和柱状晶的典型铸态组织;M42熔合区（FZ）组织为马氏体和M2C型碳化物,M42热影响区（HAZ）组织为马氏体、残余奥氏体及碳化物。X32熔合区（FZ）由类马氏体层和马氏体组织组成,X32热影响区（HAZ）组织为马氏体、残余奥氏体以及M23C6。
