日本丝袜美腿一区二区三区_99久久精品免费视频_自拍偷拍卡通动漫一区二区三区四区 _素人大屁股青椒午夜影院

The rolling processing of precision piston rod, which is formed by rolling, forms a cold working hard layer on its rolling surface. This effectively reduces the elastic and plastic deformation of the contact surface of the grinding pair, and can delay the occurrence or expansion of fatigue cracks, thereby improving the surface's corrosion resistance.
The quenching and tempering of precision piston rods is the process of quenching and tempering the piston rods. After quenching and tempering, it can effectively improve the working strength of the material, facilitate the closure of small surface cracks, hinder the expansion of corrosion benefits, and thus improve the surface corrosion resistance of stainless steel piston rods. However, not all piston rods require tempering, so tempering measures should be verified based on actual conditions and materials.