spring steel wire's strength can't meet the needs of development of modern industry. As everyone knows, in the premise of spring steel wire's quality, the mechanical property depends on the heat treatment craft. The heat treatment depends on the material. Another important way of spring steel’s high strength is to give full play to alloying elements.
1. Heat treatment
The spring steel wire needs relatively high strength and fatigue limit. It generally used under the status of quenching and mesothermal tempering, to get high elastic limit. The heat treatment has a great importance to spring’s inner quality. So how to improve the fatigue life of spring need more research. Especially for the shot peening and chemical surface modification heat treatments which have influence to the fatigue life.
The alloying elements among the spring steel wire is mainly to improve the mechanical property and processing property, and give some special performance (thermostability, anti-corrosion) to the spring steel wire. Every alloy elements have their own functions.
Carbon’s influence to spring steel wire is more important than other alloy elements. According to the using requirements, spring steel wire is usually made of alloy steel with medium to high carbon. The spring steel wire applies in the world accounts about 0.45%~0.65% of carbon.
Some spring steel wire applies Si for it has the biggest influence to the resistance of elastic weakening. The Cr and Mn can improve the hardenability of spring steel wire. The Mo can prevent temper brittleness and improve fatigue properties.
The high strength of spring steel wire is improving with the combine and cooperation of metallurgical industry and automobile industry. The performance of the spring can be promoted as well.