久久中文字幕久久无码,亚洲日韩va一区二区三区,99re6在线观看国产精品,成人国产精品秘 果冻传媒在线

　　Xingtai steel’s XG10B21 products are mainly used in the production of 8.8 bolt. Customers reflects the product composition is stable, high dimensional accuracy. For the free of annealing processing, it can directly reduce the production cost. Because of containing B elements, it has good hardenability. Drawing performance stability, cold heading does not crack, performance stability after heat treatment. The end products made by this material widely used in mechanical fasteners.