The Latest Development Trend of Stainless Steel in Japan

Judging from the changes in the demand for stainless steel in various fields in Japan in the past 10 years, each field reached its peak demand in 2006-2007. After that, it was basically constant, and there was no major change in the demand structure. However, the requirements for material properties are higher and more complex, and new materials to improve material properties are currently being developed.

In addition, in order to build a low-carbon society and a recycling-oriented society, resource conservation, energy saving and recycling are all required. Currently, new steel grades that meet these specific requirements are being developed.

The development trend of new stainless steel grades in Japan is to develop steel grades with various properties such as strength or hardness and corrosion resistance, strength and workability, steel grades aimed at energy conservation and resource conservation, and steel grades for special purposes, etc. .

As a steel with both hardness and corrosion resistance, a high-nitrogen martensitic stainless steel with 0.5% N added has been developed using the pressure induction melting casting method, which is used in automotive and semiconductor bearings, pressure and flow control valves, etc.

As a steel grade that has both strength and workability, based on SUS301, the crystal grains are refined by reducing the amount of C and adding Nb, and by increasing the amount of deformation induced martensite, the workability is maintained, and the austenite that improves the spring characteristics and fatigue strength is developed. Body steel, used for automobile engine sealing gaskets.

As a development case of energy-saving and resource-saving stainless steel, developed a resource-saving high-heat-resistant ferritic stainless steel that does not add Mo, uses Cu precipitation strengthening and Al solid solution strengthening to improve high-temperature strength, and is suitable for automotive exhaust system parts. .

In addition, in order to replace SUS304, a ferritic stainless steel with a Cr content increased to 21% and no Mo added, and a ferritic steel with Sn added to 14%-16% Cr steel to improve corrosion resistance. Among the duplex stainless steels that have both strength and corrosion resistance, alloy-saving duplex stainless steels with reduced Ni and Mo content have been developed for use in dam locks, steel-related equipment, chemical tankers, water treatment equipment, civil engineering and seawater desalination Equipment, etc.

As a special-purpose stainless steel, in a new generation of post-processing equipment, in order to prevent intergranular corrosion caused by strong oxidizing nitric acid, a high-corrosion-resistant ultra-high-purity stainless steel that can reduce impurities has been developed.