av永久免费观看,日韩在线精品视频,在线观看国产视频,国产精品久久片,国产毛片av网站,国产又粗又硬又黄又刺激,国产黄色片视频

Casus Products>> Casus

  Q37MnB5 material is a kind of European standard steel developed by Xingtai Steel. It is base on common carbon structure steel, adding trace boron element and increasing manganese content to improve that hardenability of steel and reducing cold-heating deformation tension. A customer of Xingtai Steel uses the steel to produce automobile engine structure parts and 10.9 grade high strength bolts. The customer reflects that the product has stable chemical composition , good cold heading performance and low inclusion content , and can fully meet the requirements .