Research on Surface Decarburization and Oxidation of a New Type of Spring Steel for Elastic Bar of High Speed Railway

The effect of heating temperature,holding time and type of cooling on surface oxidation and decarburization of a newly developed spring steel for elastic bar of high speed railway was investigated in laboratory.The results show that with the growth of heating temperature between 800and 1 100 ℃,the depth of oxidation layer increases gradually below 1 050 ℃then increases sharply;the depth of decarburization layer increased and the speed is more and more faster;the ferritic decarburized depth of the spring steel increases firstly,then decreases and when the temperature is 900 ℃,it reaches the maximum.With the growth of the holding time in the range of 20-120min,the depth of oxidation and decarburization layer increases gradually.Compared with temperature,the holding time has smaller effect on the depth of oxidation.On the conditions including water-cooled,air-cooled and furnace-cooled,the depth of oxidation and decarburization cooled in water is smallest,followed by cooled in air and cooled in furnace is the most serious condition.So the greater the cooling rate,the smaller the depth of oxidation and decarburization.