The RHN gas nitriding furnace is a kind of equipment used for gas nitriding Heat treatment of steel - made mechanical parts, auto parts, motorcycle brake pads, molds, etc. Here is a detailed introduction:

Structural Characteristics

Furnace Shell: Usually welded by steel plates and shaped steel. The furnace lining is made of super - light - weight and high - strength energy - saving refractory bricks, with aluminum - silicate fiber sandwiched on the outer layer and filled with expanded vermiculite powder for heat preservation. This structure has good heat - preservation performance, which can reduce heat loss and save energy.

Heating Elements: Installed on the furnace lining, high - resistance alloy wires are wound into a spiral shape and placed on the wire - supporting bricks of the furnace cavity. They can heat the furnace cavity to the required temperature for the nitriding reaction.

Furnace Can: Made of heat - resistant alloy steel, it is placed in the furnace cavity to hold the workpieces to be treated. The sealing performance of the furnace can is good, which can prevent the leakage of the nitriding atmosphere and ensure the normal progress of the nitriding process.

Gas Supply System: Includes pipes for supplying ammonia gas, organic liquid drip - feeders, etc. Ammonia gas is the main nitrogen - containing gas for the nitriding process. The organic liquid drip - feeder is used to drip organic liquids such as methanol, which helps to adjust the atmosphere in the furnace and make the temperature and atmosphere in the furnace more uniform.

Exhaust System: There is an exhaust pipe on the furnace cover, and the exhaust gas in the furnace is discharged outside the furnace through the exhaust pipe. The pressure can be adjusted by the stop valve on the exhaust pipe to ensure the stability of the pressure and atmosphere in the furnace.

Circulation and Cooling System: Some RHN gas nitriding furnaces are equipped with a hot - air circulation device to make the atmosphere and temperature in the furnace can uniform. There is also a water - cooling piston - ring sealing system to prevent fan deformation and shaft - end air leakage. In addition, the furnace is equipped with a rapid - cooling device, which can cool the workpieces quickly according to the process requirements.

Working Principle

The RHN gas nitriding furnace heats the workpieces to a certain temperature, usually between 500°C and 530°C. Then, ammonia gas is introduced into the furnace. At high temperatures, ammonia gas decomposes to produce active nitrogen atoms. These active nitrogen atoms diffuse into the surface of the workpieces and gradually penetrate into the interior, forming a nitrogen - containing strengthened layer on the surface of the nitrided workpieces. This layer can improve the surface hardness, wear resistance, fatigue resistance, and corrosion resistance of the workpieces.

Process Characteristics

Low - Temperature Treatment: The treatment temperature is relatively low, generally around 520°C, and the treatment time is 3 - 90 hours, which varies according to the material of the workpiece and the required depth of the nitrided layer. Due to the low treatment temperature, the workpiece has less deformation, which is beneficial to maintaining the dimensional accuracy and shape of the workpiece.

Wide Applicability: It is not limited by the type of steel. Carbon steel, low - alloy steel, tool steel, stainless steel, cast iron, and iron - based powder - metallurgy materials can all be nitrided. The surface hardness of the workpiece after nitriding is related to the nitriding process and material.

Significant Performance Improvement: It can significantly improve the fatigue strength, wear resistance, and corrosion resistance of the workpiece. In dry - friction conditions, it also has the properties of anti - scuffing and anti - seizure, which improves the service life and reliability of the workpiece.

Good Toughness of Nitrided Layer: The nitrided layer formed by gas nitriding has a certain toughness while being hard, and is not easy to peel off, which can better withstand the action of external forces.