Spring steel production process
In order to make the comprehensive performance and service life of alloy spring steel significantly improved, it is not enough to improve the smelting process alone. We must continue to seek for beneficial alloy elements, develop new production processes and new steel grades to meet the ever-increasing demands.
1. Multi-alloying of spring steel
The standard alloy spring steel is not widely used for alloy elements, and the alloy series is relatively simple, failing to fully utilize the effects of multi-alloying. The latest trend in the alloying of spring steel is to make full use of the composite alloying effect of alloying elements and to expand the range of use of alloying elements, especially the use of previously unused trace alloying elements, using multiple (even seven or more) alloy series. To improve the hardenability of spring steel, reduce the decarburization tendencies and improve the overall performance of spring steel.
For steels that are sensitive to decarburization, adding a small amount of chromium, vanadium, niobium, and molybdenum to the steel can improve the decarburization sensitivity of the steel and reduce decarburization of the spring steel. Adding trace amounts of boron, vanadium, molybdenum, niobium, and chromium can increase Spring steel anti-reduced.
India's Ved.Parkash research shows that adding chromium to the silicon-manganese spring steel can increase the hardenability and yield strength of the spring steel (plus 0.5% Cr increases 15%), and the decarburized layer is significantly reduced. When smelting 60Si2Mn spring steel, Nanchang Steel Works increased the residual chromium content in the steel to 0.35% to 0.85%, and found that the mechanical properties of the flat steel produced had reached the level of 55SiMnVB. The trace amount of boron can prolong the incubation period of the phase change of the spring steel, reduce the critical quenching rate, thereby increasing the hardenability of the steel, and its optimum content is 0.0005% to 0.003%. According to relevant literature reports: steel contains 0.0015 %-0.003% B, can replace 1.0%-1.25% Ni, 0.1%-0.25% Mo, 0.30%-0.35% Cr, 0.2%-0.7% Mn, 0.1% V, 1.6 % Si, 0.001 % B can be equivalent to 1.33% Ni + 0.31% Cr + 0.04% Mo . Vanadium and niobium can refine grains and improve the quality of steel; molybdenum and nickel can improve the plasticity and surface finish of steel.