久久中文字幕一区二区三区,日本99热,高清av一区,日韩狠狠操,久久久一本精品99久久精品66,1级片网站,aaaaaaa欧美黄色大片

Xingtai Steel high quality spring steel wire rod 55SiCrA is mainly used in the production of automobile suspension spring, it has higher resistance to play performance, using strength reduction, the fatigue test must reach 500000 times without fracture.This steelhas a very high requirements in the process of smelting and rolling on chemical composition, inclusion quantity and shape distribution, gas content, surface quality, the decarburization layer, microstructure, mechanical properties, high dimensional accuracy and other requirements.Customers reflect the various performance indicators such as mechanical propertiesof steel rolling materials, non-metallic inclusion, surface quality and the depth of decarburization layer, can meet the quality requirements.