【摘要】 针对石油钻采设备的低温服役条件,考察了石油工业常用35CrMoA钢及ZG35CrMo铸钢的冲击性能以及热处理工艺、毛坯尺寸和温度等因素的影响。冲击试验结果表明,35CrMoA钢的冲击性能在试验温度范围内随温度降低而逐渐下降,并且在0～-30℃范围内发生韧脆转变。在常规热处理条件下,毛坯尺寸对35CrMoA钢的冲击性能具有显著影响,特别是在室温及不太低的温度(-20℃～20℃)下,取自中等尺寸(130mm)毛坯的试样表现出较好的冲击性能;而取自较小尺寸(60mm)及较大尺寸(220mm)毛坯的试样冲击性能明显降低,反映出热处理过程中适中的冷却速度有利于改善钢的冲击性能。铸钢ZG35CrMo的低温冲击性能,特别是在-40℃～-60℃之间与35CrMoA钢相差不大,表明加工状态(轧制或铸造)对冲击性能的影响可能主要表现在室温及其以下部分温度区间。值得注意的是,当温度从-20℃下降至-60℃时,铸钢ZG35CrMo冲击性能的下降幅度远小于35CrMoA钢。此外,在各个相应试验温度下,35CrMoA钢及铸钢ZG35CrMo的冲击断口特征基本相同。更多还原

【Abstract】 According to the service conditions of petroleum devices at low temperature,the impact properties of 35CrMoA steel and cast steel ZG35CrMo applied commonly in petroleum industry and the effects of the processing conditions,blank sizes,and temperature were respectively studied.The results of the impact tests showed that the impact properties of 35CrMoA steel and cast steel ZG35CrMo decreased with the decreasing test temperature and there existed a ductile-brittle transition between -30℃ and 0℃.The effect of the blank sizes on the impact properties of 35CrMoA steel was evident under the conventional heat treatment conditions.The specimens cut from the blanks with moderate sizes (130mm) displayed good impact properties,particularly at ambient and moderately low temperatures from -20℃ to 20℃,and the impact properties of the specimens from both small (60mm) and big (220mm) blanks were remarkably decreased.It was demonstrated that moderate cooling rates during the heat treatments would be beneficial to improve the impact properties of steels.The impact properties of the cast steel ZG35CrMo at low temperatures,especially between -60℃ and -40℃,were almost same as that of 35CrMoA steel,which indicated that impact properties of 35CrMo steels were sensitive to the processing conditions only at ambient and moderate low temperatures.It should be mentioned that,with the test temperature decreased from -20℃ to -60℃,the impact property decrease amplitude of the cast steel ZG35CrMo was much smaller than that of 35CrMoA steel.In addition,the impact fractures of both 35CrMoA steel and cast steel ZG35CrMo revealed similar characteristics at every corresponding test temperatures.更多还原