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一、前言 可伐合金由于使用上耐寒的需要,要求具有较低的马氏体生成温度(简称M点)以防止低温膨胀系数发生剧变而造成部件失效,亦即要求Ar_3的起始点越低越好。在чMTy2977-51的技术条件中,规定此点不得超过-70℃。根据本所二年半来试制的检验考查结果,由于Ar_3大于-70℃而报废的占26炉/271炉,占9.6％,尤其在试制初期,此种现象更为突出,这是一个颇堪注意的问题。因为影响马氏体(简称M)转变温度的主要因素从钢的本质来说是其化学成分,所以如能根据化学成分预计到马氏体转变点,则对生产控制将有良好的作用。
First, Foreword Kovar alloy due to the use of the needs of the cold, requiring a lower martensite temperature (M point) to prevent the low temperature coefficient of expansion caused by the failure of components, which requires that the lower the starting point of Ar_3 it is good. In чMTy2977-51 technical conditions, the provisions of this point shall not exceed -70 ℃. According to the two and a half years trial production and test results of the test, because the Ar_3 is greater than -70 ℃ and scrap 26 furnaces / 271 furnaces, accounting for 9.6%, especially in the early trial, this phenomenon is more prominent, which is a rather worthy Attention questions. Because the main factor affecting the martensite (M) transition temperature is its chemical composition from the nature of the steel, controlling the martensitic transformation point according to the chemical composition will have a good effect on the production control.