Surface Quenching

1.Definition:

The surface layer of the workpiece is rapidly heated, and the surface layer reaches the quenching temperature before a large amount of heat is transferred to the interior, and then it is quickly quenched to obtain the predetermined quenching structure. Surface quenching of steel is mostly used for parts that require wear resistance, torsion resistance, bending fatigue resistance and contact fatigue resistance. Steel parts are generally normalized or quenched and tempered before surface quenching.

2.Classification:

In order to reach the temperature above the phase transition point within the limited depth of the workpiece surface, the surface of the workpiece must be heated with a very high energy density, so that the heat on the surface of the workpiece cannot be transferred to the center, resulting in a great temperature difference. Therefore, surface quenching is often named and classified according to the form of energy supplied to the surface.

Induction heating surface quenching. That is, a quenching method in which an eddy current with a high current density is generated on the surface of the workpiece based on the principle of electromagnetic induction to heat the surface of the workpiece.

Flame quenched. That is, the surface quenching method of directly heating the surface of the workpiece with a very high temperature combustible gas flame.

Electrical contact heating surface quenched.Using the contact resistance between the contact and the workpiece, low voltage and high current, the temperature of the contact rises rapidly. By moving the contact across the surface of the workpiece at a certain speed, the surface layer can be heated to the quenching temperature and hardened under the cooling of the workpiece itself. This method is simple and feasible, and is suitable for local surface quenching of large pieces.

Electrolyte heating surface quenching. That is, the workpiece is inserted into the electrolyte as an electrode, and the quenching method is used to heat the surface of the workpiece by using the cathode effect.

The most common applications are induction heating surface quenching and flame quenching. In addition, there are some other surface quenching methods such as laser heating surface quenching, electron beam heating surface quenching, and plasma beam heating surface quenching.

3.Application:

The purpose of surface quenching is to obtain a surface with high hardness and high wear resistance, while the core still maintains the original good toughness. It is often used in machine tool spindles, gears, crankshafts of engines, etc

Gear shafts and gear are the main products of CIC Luoyang Heavy Machinery Co.,Ltd . And surface quenching is an important part of heat treatment, which is the key to long-term safe and reliable operation of gear shafts and gear products.

We, CIC Luoyang Heavy Machinery Co.,Ltd provide products with reliable quality and good performance to meet their requirements.