By Titi | 17 September 2021 | 0 Comments
Why is heat treatment necessary for machining?
The knowledge of heat treatment design requirements for parts is basically based on the knowledge of material use and processing variations, so it is a very systematic knowledge structure.
First of all, we need to understand how many ways the so-called heat treatment in the machining process of parts actually includes? In view of the frequency and importance of the various ways in the machining process, we choose the following ones for analysis.
In the machining process, we use the most four types of heat treatment: annealing, normalizing, quenching and tempering.
Annealing Treatment
Definition of annealing treatment: a metal heat treatment process in which metal parts are heated to a certain high temperature, held for a period of time, and then allowed to cool naturally.
Its main function.
A, reduce the hardness of the parts, improve the cutting performance.
B, eliminate residual stress in the parts, stabilize the size, reduce the probability of deformation and cracking.
C, refine the grain, adjust the organization, eliminate material defects.
D, uniform material organization and composition, improve material properties or for the subsequent heat treatment process to do organizational preparation.
Normalizing treatment
Definition of normalizing treatment: the metal parts are heated to a certain high temperature, kept for a period of time, and then allowed to cool in the air using water spray, spray, blowing air, etc. Its difference with annealing treatment is that its cooling rate is faster, so the obtained material organization is finer and the mechanical properties are improved.
Its main functions are.
A. Removing the internal stress of the material.
B. Reduce the hardness and improve the plasticity of the material.
Quenching Treatment
Definition of quenching treatment: the metal parts are heated to a critical temperature of Ac3 or Ac1 above the temperature, held for a period of time, so that all or part of the austenite, and then cooled faster than the critical cooling rate to below Ms for martensitic transformation of the heat treatment process.
Its main role.
A, substantially improve the rigidity, hardness, wear resistance and fatigue strength of the parts.
B, to meet the ferromagnetism, corrosion resistance and other physical and chemical properties of some special steel.
Tempering Treatment
Definition of tempering treatment: It is a heat treatment in which the steel after quenching and hardening or normalizing treatment is then immersed in a lower than critical temperature for a period of time and then cooled down at a certain rate to increase the toughness of the material.
Its main role.
A, eliminating the residual stress generated by the quenching of the workpiece, to prevent deformation and cracking.
B, adjust the hardness, strength, plasticity and toughness of the workpiece, to achieve better performance requirements.
C, stable organization and size, to ensure accuracy.
D, improve and enhance the processing performance.
When we design parts that require heat treatment, there are only the following requirements:
A, eliminating the casting stress of the material, the purpose of which is to obtain more stable machining dimensions and accuracy.
B, improve the cutting performance of the parts, the purpose is to process the parts in the process of machining more efficient, better processing quality, lower processing costs.
C, to improve the rigidity, hardness and wear resistance of the parts.
Now because the CNC performance of the equipment is getting better and better, the degree of automation is getting higher and higher, many people feel that the traditional mechanical knowledge has been in decline, in fact, no, these things are a foundation, if not this foundation, you will find that you still can not make good use of these advanced technologies, this is a gradual deepening of the process, the technology needs to be practiced step by step on the road.
First of all, we need to understand how many ways the so-called heat treatment in the machining process of parts actually includes? In view of the frequency and importance of the various ways in the machining process, we choose the following ones for analysis.
In the machining process, we use the most four types of heat treatment: annealing, normalizing, quenching and tempering.
Annealing Treatment
Definition of annealing treatment: a metal heat treatment process in which metal parts are heated to a certain high temperature, held for a period of time, and then allowed to cool naturally.
Its main function.
A, reduce the hardness of the parts, improve the cutting performance.
B, eliminate residual stress in the parts, stabilize the size, reduce the probability of deformation and cracking.
C, refine the grain, adjust the organization, eliminate material defects.
D, uniform material organization and composition, improve material properties or for the subsequent heat treatment process to do organizational preparation.
Normalizing treatment
Definition of normalizing treatment: the metal parts are heated to a certain high temperature, kept for a period of time, and then allowed to cool in the air using water spray, spray, blowing air, etc. Its difference with annealing treatment is that its cooling rate is faster, so the obtained material organization is finer and the mechanical properties are improved.
Its main functions are.
A. Removing the internal stress of the material.
B. Reduce the hardness and improve the plasticity of the material.
Quenching Treatment
Definition of quenching treatment: the metal parts are heated to a critical temperature of Ac3 or Ac1 above the temperature, held for a period of time, so that all or part of the austenite, and then cooled faster than the critical cooling rate to below Ms for martensitic transformation of the heat treatment process.
Its main role.
A, substantially improve the rigidity, hardness, wear resistance and fatigue strength of the parts.
B, to meet the ferromagnetism, corrosion resistance and other physical and chemical properties of some special steel.
Tempering Treatment
Definition of tempering treatment: It is a heat treatment in which the steel after quenching and hardening or normalizing treatment is then immersed in a lower than critical temperature for a period of time and then cooled down at a certain rate to increase the toughness of the material.
Its main role.
A, eliminating the residual stress generated by the quenching of the workpiece, to prevent deformation and cracking.
B, adjust the hardness, strength, plasticity and toughness of the workpiece, to achieve better performance requirements.
C, stable organization and size, to ensure accuracy.
D, improve and enhance the processing performance.
When we design parts that require heat treatment, there are only the following requirements:
A, eliminating the casting stress of the material, the purpose of which is to obtain more stable machining dimensions and accuracy.
B, improve the cutting performance of the parts, the purpose is to process the parts in the process of machining more efficient, better processing quality, lower processing costs.
C, to improve the rigidity, hardness and wear resistance of the parts.
Now because the CNC performance of the equipment is getting better and better, the degree of automation is getting higher and higher, many people feel that the traditional mechanical knowledge has been in decline, in fact, no, these things are a foundation, if not this foundation, you will find that you still can not make good use of these advanced technologies, this is a gradual deepening of the process, the technology needs to be practiced step by step on the road.
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