1. Copper alloy
The general selection of the brand is QA19-2, HPb59-1-1. It is suitable for low pressure valves with nominal pressure less than or equal to 1.6MPa and temperature less than 200 degrees

2, carbon steel
The general selection of A5, 35 steel, after nitriding, suitable for the nominal pressure less than equal to 2.5MPa of the ammonia valve, water, steam and other medium low, medium pressure valves. A5 steel is suitable for valves with a temperature of not more than 300 degrees; 35 steel is suitable for a temperature of not more than 450 degrees. (Note: the actual route proves that the valve rod is made of carbon steel nitriding can not solve the corrosion problem well, and should be avoided.)

3. Alloy steel
The general selection of 40Cr, 38CrMoA1A, 20CrMo1V1A and other materials. After chromium plating, 40Cr is suitable for water, steam, oil and other media with nominal pressure less than equal to 32MPa and less than 450 degrees. 38CrMoA1A is treated by nitriding and can withstand the pressure of 10MPa at the working temperature of 540 degrees. It is often used on the valve of the power station. 20CrMo1V1A can withstand the pressure of 14MPa at the working temperature of 570 degrees, which is usually used on the valve of the power station.