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0 前言 为确定钢焊接时的预热温度,一些学者曾提出了很多方法。这些方法考虑了部分或全部对冷裂纹有影响的重要因素,如化学成分、焊缝金属扩散氢含量、焊接热输入、焊缝厚度、焊接残余应力以及接头的拘束度等。而这些方法在评价各种因素的影响程度方面却存在着明显的不同。例如,有些方法认为焊缝金属中氢含量的影响是线性的,但另外一些方法却认为是对数性的;针对钢的化学成分,在评价合金元素的重要性方面,各方法间也有差异。
0 Introduction To determine the preheating temperature of steel welding, some scholars have proposed many ways. These methods take into account some or all of the important factors that have an impact on cold cracking such as chemical composition, diffusible hydrogen content in the weld metal, weld heat input, weld seam thickness, weld residual stress, and the degree of restraint in the joint. However, there is a clear difference between these methods in evaluating the impact of various factors. For example, there are methods that consider the effect of hydrogen content in weld metal to be linear, but other methods are considered logarithmic; the chemical composition of steel is also different in the methods used to evaluate the alloying element’s importance.