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Several different steel sheets were tested for energy absorption, using hat square columns and dynamic crash testing. Results indicate that steel sheets containing large volume fraction of retained austenite have relatively high energy absorption. The relationship between retained austenite and energy absorption was analyzed. These special steel sheets have already been successfully used for production body parts, such a front-side-member, without difficulties arising in volume production.

An investigation of anti-corrosion steel sheets (non-galvanized) which contain copper for automobile body parts has been conducted. Copper additives accelerate the formation of amorphous substrates. These substrates decrease the rate of corrosion. In order to retain the steel's formability and weldability, the contents of the alloying elements have been optimized. As a result, this newly developed steel sheet can be used for many different applications such as door sashes and door panels of mass produced cars. This paper describes the key properties of the newly developed steel sheet and additionally the mechanism of corrosion prevention, weldability, formability, and so on.

The vibration damping composite steel sheet was improved in properties such as dependence on temperature, bending rigidity, press formability and spot weldability and compared with damping materials currently used by reviewing composition and adhesion strength of the resin and the mechanical property of the steel skin sheets. By applying the above-mentioned materials to the floor and wheel-house panels, a reduction in noise and vibration was obtained in the application test, and improvement in door shutting noise was also revealed when applying these materials to the door panels.

Automotive parts produced by cold or hot forging steel bars are often heat treated after forging to reduce their grain size and obtain improvements in mechanical properties such as tensile, impact and fatigue properties. If heat treatments after forging can be eliminated, savings in energy and handling costs could be realised. Although rolling and cold drawing without additional heat treatments have been already used, hot forged components have not except a few applications because of low toughness properties when heat treating after forging is omitted. Tests in our laboratory have shown that the toughness and other mechanical properties of hot forged parts can be significantly improved without the use of post heat treatments. Results were as follows: 1. High strength and high toughness are obtained by decreasing carbon contents, increasing manganese, adding both of microalloying elements (V, Ti). 2.