SURFACE HARDENING
Surface hardening refers to a heat treatment method in which the surface layer is austenitized by rapid heating without changing the chemical composition and core structure of the steel to strengthen the surface of the part.
The main methods of surface heat treatment include flame quenching and induction heating heat treatment. Commonly used heat sources include oxygen acetylene, oxypropane, induction current, laser, and electron beam.
INDUCTION HEATING
A method of using alternating current to induce huge eddy currents on the surface of the workpiece to quickly heat the surface of the workpiece.
Induction heating is divided into:
1, High-frequency induction heating, the frequency is 250-300KHz, the depth of the hardened layer is 0.5-2mm;
2, Medium frequency induction heating, the frequency is 2500-8000Hz, and the depth of the hardened layer is 2-10mm;
3, Power frequency induction heating, the frequency is 50Hz, and the depth of the hardened layer is 10-15mm.
FLAME HEATING
The method of using acetylene flame to directly heat the surface of the workpiece. The cost is low, but the quality is not easy to control.
LASER HEATING
A method of heating the surface of the workpiece with a high-energy density laser.
Feature: High efficiency and good quality.
Laser surface strengthening can be divided into laser phase change strengthening treatment, laser surface alloying treatment and laser cladding treatment.
This process is mainly used for locally strengthened parts, such as blanking dies, crankshafts, cams, camshafts, spline shafts, precision instrument guides, high-speed steel tools, gears, and internal combustion engine cylinder liners.
BLUEING OXIDIZING
A process in which steel or steel parts are heated to an appropriate temperature in air-water vapor or chemical drugs to form a blue or black oxide film on the surface. Also called blackening.
Commonly used in precision instruments, optical instruments, tools, hardness blocks and standard parts in the machinery industry.
PHOSPHATING
The process of immersing the workpiece (steel or aluminum, zinc) in a phosphating solution (some acid-based phosphate-based solutions), and depositing a layer of water-insoluble crystalline phosphate conversion film on the surface is called phosphating . Phosphating is widely used in anti-corrosion technology, metal cold deformation processing industry.
