DBY180-28-3 What is the difference between two heat treatment processes of reducer carburizing and nitriding

DBY180-28-3 The two heat treatment processes of reducer carburizing and nitriding are as follows:

• Different elements infiltration :

• Carburizing quenching : Carbon elements are penetrated into the surface of the steel to form a high-carbon surface, with a general carbon content between 0.8% and 1.2%. After quenching + low-temperature tempering, the surface layer obtains high-hardness martensite structure.

• Nitriding : Infiltrates nitrogen elements into the surface layer of steel or alloys to form nitrides, such as FeN, CrN, etc., and extremely high hardness is obtained without quenching.

• The process temperature and time are different :

• Carburizing and quenching : The temperature is higher, usually between 850-950℃, and the insulation time is longer, usually from several hours to dozens of hours.

• Nitriding : The temperature is lower, generally between 500-560℃, but the insulation time is longer, which may reach more than ten to tens of hours, or even hundreds of hours.

• Different performance characteristics :

• Hardness : The hardness of the nitriding surface layer is higher, up to 950-1200HV; the hardness after carburization and quenching is generally 58-64HRC, about 600-700HV.

• Wear resistance : Nitriding is better than carburizing, and is especially suitable for withstanding small impact and high wear.

• Fatigue strength : The surface layer of nitriding forms compressive stress, and the fatigue strength increases more significantly; carburizing may produce residual stress due to quenching, so the process needs to be controlled to reduce the risk of cracking.

• Deformation : The nitriding temperature is low, the workpiece deformation is extremely small; the carburization temperature is high, and the deformation is relatively large.

• Different materials for :

• Carburizing quenching : mainly used for low-carbon steel or low-carbon alloy steels, such as 20 steel, 20CrMnTi, etc., and hardening is achieved by relying on quenching.

• Nitriding : Suitable for medium-carbon steels, alloy structural steels, such as 38CrMoAlA, or alloys containing elements such as Cr, Al, Mo, etc. These elements can form stable nitrides with nitrogen.

• Different application scenarios :

• Carburizing quenching : used to withstand large impact loads and require hard surfaces and tough core parts, such as gears, shafts and other parts in reducers.

• Nitriding : used for parts that require high wear resistance, high precision and low deformation, such as precision machine tool spindles, valves, molds, etc. If the reducer has extremely high accuracy requirements, some of its key parts can be nitriding.