Vice President, Mahindra Ugine Steel Co. Ltd., Khopoli,
Pages: 20 Published: Jan 2002
Carbides are an essential phase in high carbon alloy steels used for bearing applications. Carbides provide wear resistance, inhibit grain growth and are the reservoirs of alloys, which enable the steel to develop the desired properties during heat treatment. High carbide heterogeneity and large carbides are known to affect adversely the wear resistance of bearing steels. Heterogeneity originates from the solidification process of ingots and cast blooms. An attempt has been made to study the effect of various steel making and processing parameters such as teeming/casting temperature, ingot size, reduction ratio, soaking time at the rolling temperature and heat treatment on the carbide banding in the commercially produced ASTM A 295 - 52100 type bearing steel. Carbide banding was found to decrease with the decrease in super heat and increase in the reduction ratio. Increasing soaking time at the rolling temperature also decreased the degree of banding. Increasing the austenetizing temperature or increasing the soaking time at the same austenitizing temperature also reduced the degree of banding; the effect of temperature is being more significant. High temperature soaking prior to hot rolling significantly decreased the degree of banding in continuously cast products. Carbide banding reduced with reduction in carbon content and sulphur content. Other alloying elements had very little or no significant influence on carbide banding.
High carbon bearing steel, carbides, carbide banding, solidification, steel making
Paper ID: STP10844S