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How to solve the common problems during the metal heat treatment process


How to solve the common problems during the metal heat treatment process

During the High frequency induction heating machine heating heat treatment, we may encounter some heating problems; 

So come on, today Kechuang will guide you to understand how to solve and kick off the heat treatment problems, to avoid material loss in production, improve heating efficiency and increase productivity.

How to solve the common problems during the metal heat treatment process

1. What are the commonly used quenching methods, and explain the principle of choosing different quenching methods?

Quenching method: 1, single liquid quenching – in a quenching medium cooling to the end of the process, single liquid quenching structure stress thermal stress than

Large quenching deformation.

2. Double liquid quenching – Purpose: fast cooling between 650~Ms, make V>Vc, slow cooling below Ms, to reduce the stress of the organization.

Carbon steel: water before oil.Alloy steel: oil before air.

3. Grading quenching – after the workpiece is taken out, it stays at a certain temperature to make the temperature inside and outside the workpiece consistent, and then air cooling process, grading quenching

Fire is produced by the M phase transformation in air cooling, and the internal stress is small.

4. Isothermal quenching — refers to the isothermal bainite temperature region, the occurrence of bainite transformation, reduced internal stress, small deformation.

The principle of quenching method selection should not only consider to meet the requirements of performance, but also reduce the quenching stress as far as possible to avoid quenching deformation and opening


Three quality problems of induction heating quenching are pointed out, and the reasons are analyzed.

1) Cracking: heating temperature is too high, the temperature is uneven;Improper selection of quenching medium and temperature;Timely and insufficient tempering;material

High hardenability, segregation of components, defects, and excessive inclusion;The design of the parts is not reasonable.

2) Uneven surface hardness: unreasonable induction structure;Uneven heating;Uneven cooling;Poor structure of material (banded structure, local


3) Surface melting: the inductor structure is unreasonable;The parts have sharp corners, holes, bad, etc.The heating time is too long, and the workpiece surface is cracked


Information Center – Zhengzhou Kechuang Electronics Co., Ltd.


What problems should be considered in the optimization design of heat treatment process flow

1.  Give full consideration to the connection between cold and hot processing technology, the arrangement of heat treatment process should be reasonable;

2.  As far as possible to adopt new technology, brief heat treatment process, shorten the production cycle.The conditions required to ensure the organization and performance of the parts

Next, try to make different processes or technological processes combined with each other;

3. Sometimes in order to improve the quality of the product, prolong the service life of the workpiece, need to increase the heat treatment process.

Briefly describe the principles to be followed in inductor design

1. The coupling distance between the inductor and the workpiece should be as close as possible.

2. For the workpiece heated by the outer wall of the coil, the displacement flux guide must be added.

3. The design of the workpiece sensor with a sharp corner to avoid the sharp corner effect.

4. To avoid the magnetic field line offset phenomenon.

5. The sensor design should try to meet the workpiece can turn when heating.

 What basic principles should designers consider when selecting materials

1. Selection of materials according to the working conditions of parts, including load type and size, environmental conditions and main failure modes;.2, considering the structure, shape and size of the parts and other factors, easy to produce quenching distortion and cracking to choose better hardenability, can

2. Material treated with oil quenching or water-soluble quenching medium;

3. Understand the structure and properties of materials after heat treatment, and some of the steel grades developed for various heat treatment process methods, and the structure after treatment

And performance will be better;

4. Under the premise of ensuring the performance and life of the parts, the heat treatment process should be simplified as far as possible, especially the materials that can be saved


 What process properties should be considered when choosing metal materials to make parts

1.  Casting performance

2. Pressure processing performance

3.  Mechanical processing performance

4. Welding performance

5.  Heat treatment process performance.

  Tempering matters needing attention

Temper must be timely, after quenching parts within 4h for tempering.

Commonly used tempering methods include self tempering, furnace tempering and induction tempering.