High Precision Large Internal Ring Gear Girth gear Metal Spur Gear With Nitriding Treatment

       High Precision Large Internal Ring Gear Girth gear Metal Spur Gear With Nitriding Treatment

Gear is a common mechanical part and has an irreplaceable position in the field of general mechanical equipment. How to improve the processing quality and service life of gears has always been a topic that people continue to explore. Heat treatment is an important technical means. At present, the heat treatment of transmission gears mainly includes four processes: quenching and tempering, induction hardening, nitriding and carburizing. The nitriding technology is:

The holding temperature of the nitriding process is generally 460-600 ℃, which is a chemical heat treatment process in which active nitrogen atoms are infiltrated into the surface of the gear. After nitriding, the distortion of the gear is small, and it has higher hardness than carburizing, which can increase wear resistance, fatigue strength, anti-seizure performance, corrosion resistance and high temperature softening resistance, etc. It is widely used in automobiles and machine tools or other gears with higher requiremet of wear resisitance.

Compared with other surface treatments, the biggest advantages of nitriding treatment are:

1. The deformation is small, and the temperature of nitriding treatment is much lower than that of carburizing treatment. The ion nitridation temperature is even as low as 40°C. At this temperature, the deformation of the teeth is very small, so for the gears of general precision, it is not necessary to grind the teeth after heat treatment.

2. High hardness and good thermal hardness. After nitriding, the surface hardness can reach 850~1100HV. Such high hardness can be maintained up to 500 ° C, so the adhesion resistance and scratch resistance are superior to carburizing and surface quenching. This characteristic is particularly important for high-speed gears.

3. The fatigue strength is improved. From the point of view of fatigue strength, its improvement rate is not as good as that of carbonization and surface treatment, but its effect on reducing notch sensitivity is superior to that of carbonization. Therefore, parts with complex shapes should be treated with nitrogen.

4. It improves the corrosion resistance and has a good effect on improving the corrosion fatigue strength.

5. Improve the contact fatigue strength. The contact fatigue strength after nitriding is greatly improved than that of the quenched and tempered soft tooth surface, but generally the contact fatigue strength after nitriding is lower than that of carburizing. The nitriding process includes gas nitriding and ion nitriding. Ion nitriding is currently the most widely used in the surface strengthening treatment of gears.

The traditional carburizing gear has good comprehensive mechanical properties, but the carburizing process is complicated, the gear quenching distortion is large, and the energy consumption is large, and the nitriding gear is partially replacing the carburizing gear with its own advantages, to realize the manufacture of high-efficiency gears and Overcome many defects of carburizing and quenching. Nitriding gears have become a research hotspot in the worldwide industry as a way to improve the performance of gears and partially replace carburized gears.