The valve is an important part of the engine. The function of the valve is to inflow air into the engine and discharge the exhaust gas after combustion. The valve working environment is abominable and contact with gas directly. The maximum temperature of the exhaust valve is up to 800 degrees C, and it is at the end of the lubrication cycle, and the valve is open and closed frequently when the valve works, and the valve parts are easily damaged. Therefore, attention should be paid to the repair of valve parts to ensure that they are in normal working condition.