高潮喷水一区二区三区,色欲av蜜臀av久久久久久蜜桃,91精产,wwwww.国产

　　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.