Special environment with bearing steel
In automotive, industrial machinery, household appliances, intelligence machine mechanical device, such as the bearing not only requires lightweight, compact, and the requirements to improve bearing performance to adapt to the use of harsh environment.To meet this need, must take the material and heat treatment process, shape and size optimization, but also need to be used with users seek the surrounding parts of integration of the material.
Japan datong special steel company has been committed to development suited to particularly harsh environment using bearing materials and heat treatment process suitable for this kind of material.Following with bearing manufacturers to jointly develop the company and has been put into practical application of the high temperature bearing steel and the company alone the development of resistance to foreign body bearing steel profile.
1. The high temperature bearing steel STJ2
With the continuous improvement of automobile engine output power and high speed industrial machinery and FengBiHua, bearing using the environment temperature to rise.Hope to develop in 473 ~ 523 k temperature keep the performance of the bearing.Under this temperature range, and if you use the practice of modified treatment weeken the SUJ2, will reduce the hardness of roll life characteristics., on the other hand, although the type used in jet engines, such as precipitation hardening alloy steel - M50 with full roll life is at the same temperature range, but the alloy containing 10% of alloy elements such as Cr, Mo, V, so the material cost is high, the heat treatment is complex, the lack of generality., therefore, will develop to a high amount of alloying elements added control at a minimum, at the same time, considering the high temperature heat treatment and machining work as a goal to improve quenching hardness of bearing steel, improve the resistance to tempering softening in preventing of softening under high temperature is effective.
The company investigated the alloy elements on the influence of the quenching and tempering hardness hardness, used the C elements for improving the quenching hardness, in order to improve the resistance to temper soften using the Si element.Therefore, for the comparison of bearing steel SUJ2, developed to increase the content of C and Si in order to prevent the high temperature hardness decrease, by adding Ni element STJ2 keep rolling characteristics of materials for high temperature bearing steel.
2. Resistance to foreign body DCJ2 of bearing steel
For car transmission and differential bearing, due to the oil mixed with foreign body (silt, cutting powder), once the foreign body bite into the bearing rolling surface caused indentation on the surface of the rolling early spalling occurs, to develop resistance to foreign body bearing steel.
By foreign environment with the images of rolling fatigue test, the result of the discussion is to improve the mixed with foreign body under the environment of the service life of the bearing, by increasing the surface of the residual austenite volume, improve the surface hardness or the toughness of the matrix effect.
Development to add more than 2% of the Mn's resistance to foreign body bearing steel DCJ2 in quenched and tempered condition of foreign body fatigue life of rolling resistance and rolling fatigue life compared with SUJ2 clean oil, its residual austenite volume is high, under the condition of the foreign bodies with shows like in clean oil, excellent rolling fatigue life has clear DCJ2 nitrocarburizing treatment steel excellent resistance to foreign life.
Datong special steel company launched high temperature bearing steel STJ2 and foreign body bearing steel DCJ2 two steel surface hardening treatment of research work, developed jointly with NTN company add Si, Ni heat resistant carburizing bearing steel has been applied to actual.And development has more than the nitrocarburizing treatment of more excellent properties of adding Mn's resistance to foreign bodies with surface hardened steel, has begun to Japan, the United States, the European bearing manufacturer for popularization and application.
