Why is heat treatment necessary in machining? This question might be a challenge for those who are not very familiar with it or newcomers to the field. Maybe even experienced people haven’t deeply considered it. So today, let’s have Chunjü Precision Machining enlighten us. Let’s take a look together. 

The heat treatment requirements for machining are actually a technical requirement in the design stage. If you are a mechanical structure design engineer, you need to have this kind of cognitive ability. If you don’t have such awareness, then you are not a qualified design engineer, or at least not a very comprehensive one. 

The understanding of the design requirements for heat treatment of parts is basically established on the recognition of the changes in material usage and processing. Therefore, it is a very systematic knowledge structure and does not exist in isolation. First of all, we need to understand exactly how many methods are included in the so-called heat treatment during the machining process of parts? 

Given the frequency and significance of various methods in the machining process, we have selected the following few for analysis, namely, a focused analysis. Among the machining processes, the four heat treatment methods we use most frequently are annealing, normalizing, quenching and tempering. Let’s conduct an analysis of them below. 

Annealing treatment: The definition of annealing treatment: It is 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 functions are: A. To reduce the hardness of the parts and improve the machinability; B. To eliminate residual stress in the parts, stabilize dimensions, and reduce the probability of deformation and cracking; C. To refine grains, adjust the structure, and eliminate material structure defects; D. To homogenize the material structure and composition, improve material properties, or prepare the structure for subsequent heat treatment processes. 

02 Normalizing treatment: The definition of normalizing treatment: Heat metal parts to a certain high temperature, hold for a period of time, and then cool them in the air by means of water spraying, mist blowing, etc. The difference from annealing treatment is that the cooling speed is faster, so the material structure obtained is finer and the mechanical properties are improved. Its main functions: A. Remove internal stress of materials; B. Reduce the hardness of materials and improve plasticity. 

03 Quenching Treatment: The definition of quenching treatment: Heat metal parts to a temperature above the critical temperature Ac3 or Ac1, hold for a period of time to make them fully or partially austenitized, and then cool rapidly at a rate greater than the critical cooling rate to below Ms for martensitic transformation. Its main functions: A. Significantly increase the rigidity, hardness, wear resistance and fatigue strength of parts; B. Meet the physical and chemical properties such as ferromagnetism and corrosion resistance of certain special steels. 

04 Tempering Treatment: Definition of tempering treatment: It refers to a heat treatment method where steel that has undergone quenching hardening or normalizing treatment is immersed in a temperature lower than the critical temperature for a period of time and then cooled at a certain rate to increase the material’s toughness. Its main functions are: A. Eliminating residual stress generated during quenching of the workpiece to prevent deformation and cracking; B. Adjusting the hardness, strength, plasticity and toughness of the workpiece to meet better performance requirements; C. Stabilizing the structure and size to ensure accuracy; D. Improving and enhancing processing performance. 

Chenju Precision focuses on precision parts processing services, offering 3-axis, 4-axis, and 5-axis CNC machining, turning and milling compound processing, CNC lathe processing, and small batch parts processing, etc. It excels in complex structural parts and can customize special fixtures and jigs for projects. Each product undergoes at least four full inspection procedures, with a quality pass rate of 99.93%. It provides high-quality small batch processing customization services for customers, with sample production within 3 days and delivery within 7 days.