The world sponge varieties of quality development direction will be around the high corrosion resistance sponge, high formability sponge, high strength and high hardness sponge, heat resistant and antioxidant sponge, high nitrogen sponge sponge on such as varieties.

High corrosion resistance sponge

The high corrosion resistance sponge can be divided into two kinds: one kind is called super sponge with Nippon steel, the YUS270 (and cr - and ni - 6 mo - N) as a representative, the corrosion resistance of titanium and quite. YUS270 chromium content and molybdenum content is higher, can effectively use nitrogen to improve corrosion resistance, YUS270 of thermal expansion coefficient between austenite and ferrite between sponge sponge. It can be applied to the seawater purification plant, chemical plant, coastal sodium chloride corrosion serious construction, etc. Ferrite sponge SUS447J1 (30 cr - 2 mo) is a kind of super sponge.

Another kind is high cleanliness of ferrite sponge. By increasing the content of chromium and molybdenum, reduce carbon and nitrogen content, can improve the corrosion resistance and formability. The typical high cleanliness ferrite sponge has the Nippon steel YUS220M (22 cr - 1.5 Mo - Ti - Nb), YUS190 and YUS190L (19 cr - 2 Mo), other sponge of chromium and molybdenum content change slightly. YUS260 (and cr and ni - 3 Mo - Cu - N), YUS110M (and cr - 12 ni - 2 si - Mo - Cu) and YUS27A - M (17 cr - 7 ni - 2 Cu - 2 si) is the latest development of high corrosion resistance sponge.

Composite add titanium and niobium can stop as a source of corrosion of the non-metallic inclusion precipitation to formation of titanium oxide passivation membrane, so as to improve corrosion resistance. Nippon steel have been YUS190 and YUS220M using this technology.

According to reports, the composite add Ti, Nb and A1 can improve the corrosion resistance. And found that traditionally considered harmful element S low chromium sponge can improve the resistance to intergranular corrosion ability, its role and nitrogen austenitic sponge to improve the corrosion resistance of the functions are the same. The future to improve corrosion resistance research will mainly focus on inclusion control and protective coatings on the surface.

High formability sponge

Ferrite sponge plastic is poor. And austenitic sponge strength is high, but high coefficient of thermal expansion, not including welding, forming.

Reduce the carbon content and nitrogen content can significantly improve formability, under certain conditions can improve drawing performance. For example, SUS430 r = 1.0, and low carbon SUS430D r = 1.6, and at the same time can be stable elongation in more than 30%. YUS436S rolling the r value obviously improved, especially the large diameter roller rolling, and SUS304 is different, in appropriate stamping conditions, these new ferritic sponge can ultra deep drawing processing. Ultra high cleanliness Fe - Cr alloy has good formability, in chrome content up to 18% of the sponge can be more than 36% of the elongation.

With sponge disc round of increased production, processing method by cutting into forging, develop good cold forging performance of new SUSMX7 sponge. Also developed add S, Pb, Se of free cutting sponge and critical compression ratio improve steel.

Recently is study can be lubrication sea bit steel plate. On the surface coated with organic coating of steel can be no oil or protective layer under the condition of the forming, improve the working environment and reduce the production cost of the request is expected to have many USES. Nippon steel and Tokai steel cooperation developed, called "Guardooat" organic coating, YuHaiMian application.

High strength and high hardness sponge

For the development of railway carriage SUS301L modification sponge can be used as high strength and high hardness of structural materials, such as automobile gasket and the pressure plate. For public works and building components, developed with good corrosion resistance of martensite sponge YUS550 (13 cr and ni - 2 mo), it can be applied to cement punching without drilling. Based on the SUS316 add nitrogen SUS316FR (16 cr - 12 ni - 2 mo - 0.09 N) can be used for fast breeder reactor, and can also be used for need high temperature strength and creep strength of the occasion. Add niobium ferrite sponge YUS180H (19 cr - 0.8 Nb) and YUS340 - MS (14 cr - 0.5 Mo - 0.3 Nb, Ti) with high temperature strength, can be used in the automotive exhaust system.

Heat resistant and antioxidant sponge

High chrome sponge with heat resistance and oxidation resistance. Add Al and Si can further improve the high chrome sponge heat resistance and oxidation resistance. YUS710 (25 cr and ni - 2 si - Mo - N) and YUS731 (19 cr and ni - 3 si - 0.7 Cu) is heat-resistant and antioxidant austenitic sponge, defect is high temperature appear expansion. To this, Nippon steel developed low expansion of HOM125 (15 cr - 4 Al) and YUS415S (12 cr - 2 si - Al) ferrite sponge. Add the Cr, Al and rare earth elements of the YUS205 - M1 and Cr - 5 Al - REM) sponge for automobile exhaust purification device, the temperature as high as 950 degrees Celsius with heat resistance and oxidation resistance.

Coated with heat resistant resin sponge had been commercialized and used for heat temperature of about 260 degrees Celsius fires, etc. Microwave oven lining require the use of heat temperature for 550 to 600 degrees Celsius heat precoating material. For such purposes, the future need to develop both heat and have good formability of the sponge.

High nitrogen sponge

Add nitrogen can improve the strength of the sponge and toughness, improve the corrosion resistance. From 1988 to 1998, 10 years have been held five topics related to the international conference. The AOD refining of high manganese austenitic sponge in the highest nitrogen content of 0.5%, such as Carpenter eighteen - plus; The pressure ESR method can be increased to 1% nitrogen content, such as JSW eighteen - n. In Ni - Cr sponge the solubility of nitrogen in the relatively small, the pressure ESR method smelting of austenitic sponge of nitrogen content in 0.5%, such as RS561. Nitrogen solubility in martensitic sponge minimum. At present, not only need to study the solubility of nitrogen in the sponge, impact on the performance of more need to study to add sponge nitrogen both economical and effective method.