Development of Ferritic Stainless Steel Sheet for Weight Sensor Substrate

This study presents a stainless steel most suitable as the metal base material for the weight sensor substrate of automobile airbags. The influence of the chemical compositions of both Al and Cr on average linear expansion coefficient and high temperature oxidation resistance was examined in order to develop the proposed stainless steel sheet.

As a result, it was found that by using a stainless steel sheet comprising high-aluminum ferritic stainless steel containing over 2.5mass%Al, it is possible to control the difference between the average linear expansion coefficients of the proposed stainless steel sheet and crystallized glass for a weight sensor in a temperature range from 20°C to 900°C. Thus, it is also possible to improve the adhesiveness between the proposed stainless steel sheet and crystallized glass. Furthermore, it was observed that the high temperature oxidation resistance improves remarkably with the increase in Al content.

Thus, 15mass%Cr-4.5mass%Al was selected as the optimum composition stainless steel for a weight sensor substrate.