加热期间弹簧钢55SiCr表面脱碳的影响因素研究

STUDY ON SURFACE DECARBURIZATION OF 55SiCr SPRING STEEL DURING HEATING

在实验室研究了加热温度、保温时间和加热炉内气氛对弹簧钢55S iCr表面脱碳的影响,并对脱碳反应进行了热力学分析。结果表明：在950℃-1250℃范围随温度升高,弹簧钢完全脱碳层厚度先增加后减小,1200℃时完全脱碳层厚度达到最大值,1250℃时由于氧化速度大于脱碳速度,完全脱碳层消失。弹簧钢完全脱碳层厚度分别随加热时间延长、气氛中CO2含量升高、O2含量升高和H2O（g）含量增加而明显增加。当温度为950℃、气氛中O2含量为1%、加热时间为35 min的条件下,可避免完全脱碳层的形成。

In the present paper,the research of effect of heating temperature,holding time and atmosphere on the surface decarburization of the spring steel 55SiCr was made in the laboratory,plus thermodynamic analysis of the decarburization reactions was made further.The results show that with the increase of heating temperature in the range of 950 ℃～1250 ℃,the thickness of complete decarburization layer of the spring steel increased firstly,then decreased inversely,when the heating temperature was 1200 ℃,the thickness of complete decarburization layer reached the maximum,and when the heating temperature was 1250 ℃,due to the speed of oxidation was faster than the speed of decarburization,the layer of complete decarburization disappeared completely.Moreover,the thickness of complete decarburization layer of the spring steel increased obviously,respectively with the prolonged time of heating,with the rise of CO2 content,O2 content and H2O（g） content in the atmosphere of heating furnace.When the heating temperature was 950 ℃ and the O2 content was 1%,the heating time was 35 minutes,the complete decarburization layer can be avoided completely.