The inner diameter of the cylinder tube represents the output force of the cylinder. The piston should slide smoothly in the cylinder, and the surface roughness of the cylinder should reach ra0.8um . The inner surface of the steel pipe column should be plated with hard chromium to reduce friction and wear and prevent corrosion. Cylinder materials are made of high-strength aluminum alloy and brass, except for high-carbon steel pipes. This small cylinder is made of stainless steel. In a corrosion-resistant environment, steel cylinders using magnetic switches or steel cylinders should be made of stainless steel, aluminum or brass. By expanding in the engine cylinder, the cylinder is converted into mechanical energy. The piston in the compressor cylinder compresses the gas to increase the pressure. The casing of a turbine or rotary piston engine is usually called a cylinder. Application of stainless steel cylindrical tube : printing ( tension control ) , semiconductor ( spot welding machine, chip grinding ) , automatic control, robot, etc. Rockwell hardness test cylindrical tube , is virtually the same as Brinell hardness test , indentation test methods , but the difference is , Rockwell indentation depth measurement primarily , Rockwell hardness test method is widely used , because Luo The Brinell hardness is suitable for testing soft metal materials , which can effectively make up for the insufficient Brinell hardness test , and the method is relatively simple. However, due to the small indentation, the hardness value is not as accurate as the Brinell hardness value.