1. The gas nitriding furnace before nitriding must be a workpiece that has undergone normalization or quenching and tempering treatment. First, use gasoline and alcohol to scrub the surface of the gas nitriding furnace workpiece, and there must be no rust, oil, or dirt present. After being loaded into the furnace, symmetrically tighten the furnace cover compression bolts.

 

2. Feed cooling water into the inlet of the furnace tank and furnace cover for circulating water cooling. The cooling water of the pipeline on the gas nitriding furnace cover is inlet at the lower end and outlet at the upper end. The furnace tank is separately inlet and outlet, and all water pipes on the gas nitriding furnace cover can be connected in series according to the principle of low inlet and high outlet, with one inlet for inlet and one outlet for drainage.

 

3. Before heating up the gas nitriding furnace, nitrogen gas should be sent for exhaust, and the flow rate during exhaust should be more than twice that during use. After 10 minutes of exhaust, the manufacturer of the iron pot gas nitriding furnace sets the temperature control instrument to 150 ℃. The automatic heating switch of the nitriding furnace is turned on, and the gas nitriding furnace is heated at 150 ℃ for 2 hours while exhausting. Then, the temperature control instrument is set to 530 ℃, and the ammonia flow rate is reduced to maintain positive pressure in the furnace.

 

4. The exhaust port has a relatively small upward pressure of gas flow. When the furnace temperature rises to 530 ℃, constant temperature and constant flow nitriding is carried out for 3-20 hours. Then, the ammonia pressure is increased a bit to maintain a moderate pressure in the exhaust, nitriding is carried out for 4-70 hours, and the ammonia pressure is reduced for 1-2 hours. The power is cut off and a small amount of ammonia is supplied to maintain positive pressure in the furnace.

 

Soft nitriding methods can be divided into three categories: gas soft nitriding, liquid soft nitriding, and solid soft nitriding. At present, gas soft nitriding is widely used in domestic production. Gas soft nitriding refers to low-temperature nitrocarburizing in an atmosphere containing active nitrogen and carbon atoms. Common co nitriding media include urea, formamide, ammonia and Triethanolamine, which undergo thermal Chemical decomposition reaction at soft nitriding temperature to produce active nitrogen and carbon atoms. Activated nitrogen and carbon atoms are absorbed by the surface of the workpiece and diffuse into the surface of the workpiece, thereby obtaining a nitrogen carbon co infiltrated layer mainly composed of nitrogen. Nitriding furnace, through the production line of type soft nitriding furnace, is commonly used for gas soft nitriding at a temperature of 560-570 ℃, because the hardness value Z of the nitriding layer is high at this temperature. The nitriding time is usually 2-3 hours, as over 2.5 hours, the depth of the nitriding layer increases slowly with time.

 

After completing the first three steps and resolving the problem of air leakage in the ion nitriding furnace body or confirming that the air leakage is not caused by the furnace body, reconnect the air inlet pipe that was separated from the ion nitriding furnace body in the first step to the furnace body bell cover (and ensure that the joint is sealed properly), first turn off all flow meters, and then start the vacuum pump to vacuum the furnace body. The purpose of this step is to check the air leakage situation in the gas supply system. If any air leakage is found in the equipment, the air inlet joint can be checked, The sealing condition of each connection of the gas pipe and various gas source flow converging tees until the problem of air leakage is eliminated.