1, High formability stainless steel
The plasticity of ferritic stainless steel is poor. While the strength of austenitic stainless steel is high, but has a high coefficient of thermal expansion, is not conducive to the forming process, including welding. Reduce the carbon and nitrogen content can significantly improve the formability, in certain conditions can improve the deep punching performance. For example, SUS430 has r = 1.0, while the low-carbon SUS430D has r = 1.6, while the elongation can be stabilised at over 30%. The r value of continuous rolled YUS436S is significantly improved, especially after rolling by large diameter rolls, and unlike SUS304, these new ferritic stainless steels mentioned above can be processed in ultra-deep stamping under appropriate stamping conditions. Ultra-high cleanliness Fe-Cr alloy has a good formability, in the chromium content of up to 18% of stainless steel can be obtained greater than 36% elongation. Along with the growth of stainless steel disc production, processing methods from cutting to forging, the development of new stainless steel with excellent cold forging performance SUSMX7. also developed to add S, Pb, Se easy to cut stainless steel and critical compression ratio improvement steel. Recently, research is being done on lubricated stainless steel sheet. In the surface of the organic coating on the steel plate can be formed without lubricant or protective layer, in the improvement of the working environment and reduce the production cost requirements can be expected to have many uses. Nippon Steel has worked with Tokai Steel to develop an organic coating called “Guardooat” for stainless steel applications.
2, High strength and high hardness stainless steel
SUS301L modified stainless steel developed for railway carriages can be used as a high strength and high hardness structural material, such as gaskets and pressure plates for automobiles. For public works and construction components, a martensitic stainless steel with good corrosion resistance, YUS550 (13Cr-2Ni-2Mo), was developed which can be applied to cement punching without drilling. SUS316FR (16Cr-12Ni-2Mo-0.09N) with the addition of nitrogen to SUS316 can be used in fast breeder reactors and promises applications where high temperature strength and creep strength are required. The ferritic stainless steels YUS180H (19Cr-0.8Nb) and YUS340-MS (14Cr-0.5Mo-0.3Nb-Ti) with the addition of niobium have high high temperature strength and can be used in automotive exhaust systems.
