Surface heat treatment is a metal heat treatment process that only heats the surface of the workpiece to change the mechanical properties of the surface. In order to only heat the surface layer of the workpiece without allowing too much heat to pass into the inside of the workpiece, the heat source used must have a high energy density, that is, a larger amount of heat energy is given to the workpiece per unit area so that the surface or part of the workpiece can be short-term or instantaneous. reach a high temperature. The main methods of surface heat treatment are flame quenching and induction heating heat treatment. Commonly used heat sources are flames such as oxyacetylene or oxy propane, induced current, laser, and electron beam.
Flame heated surface hardening
How to operate
The flame burned with oxygen-acetylene mixed gas is sprayed onto the surface of the steel part, and it is heated rapidly. When it reaches the quenching temperature, it is cooled by spraying water immediately.
Purpose
Improve the surface hardness, wear resistance, and fatigue strength of steel parts, and the core still maintains a tough state.
Application points
1. Mostly used for medium carbon steel parts, generally, the depth of the hardened layer is 2-6mm;
2. It is suitable for large workpieces produced in single or small batches and workpieces that require partial quenching.
Induction Heating Surface Hardening
How to operate
Put the steel part into the inductor, so that the surface layer of the steel part generates an induced current, heats it to the quenching temperature in a very short time, and then sprays water to cool it.
Purpose
Improve the surface hardness, wear resistance, and fatigue strength of steel parts, and maintain the toughness of the core.
Application points
1. Mostly used for medium carbon steel and Zhongtang alloy structural steel parts;
2. Due to the skin effect, the hardened layer of high-frequency induction hardening is generally 1-2mm, that of intermediate-frequency quenching is generally 3-5mm, and that of high-frequency quenching is generally greater than 10mm.
