Accurate heat treatment quenching technology of high-carbon high-chromium tool steel precise part

Abstract

The invention provides an accurate heat treatment quenching technology of a high-carbon high-chromium tool steel precise part and belongs to the field of heat treatment of tool steel materials. The accurate heat treatment quenching technology is provided for a two-tool-edge stamping part in a precise stamping die, wherein the material of the part is high-carbon high-chromium ledeburite cold work die steel ASSAB XW-5 imported from Sweden, the main alloy ingredients of the high-carbon high-chromium ledeburite cold work die steel ASSAB XW-5 comprise 2.05% of C, 12.5% of Cr, 1.3% of W, 0.8% of Moand 0.3% of Si. According to the accurate heat treatment quenching technology, based on different workpiece hardness requirements, different tempering temperatures are adopted, so that a small designed hardness difference needed by two tool edges of the precise stamping die can be achieved, different temperature keeping times are adopted for different workpiece thicknesses, so that the hardenability of the material is reliably guaranteed, the crystal structure in the material can be accurately controlled to be refined, uniform and stable, and the part can be good in wear resistance, long in service life, high in reliability and stable in dimension and meets the use demands for a precise part. The accurate heat treatment quenching technology is mainly implemented through the following stepsand technical scheme that (1) workpieces with the thickness difference smaller than 5 mm are placed in a quenching furnace and are preheated to 150 DEG C in two steps; (2) the workpieces are heated to the quenching temperature and keep the temperature for the time of t in two steps in the quenching furnace; (3) the workpieces are discharged from the furnace and air cooled to 50-70 DEG C; (4) theworkpieces are fed into a tempering furnace to be heated to T DEG C for tempering and keep the temperature for the time of t twice, and then the workpieces are discharged from the tempering furnace and air cooled (please refer to the figure 1).

Description

technical field [0001] The invention belongs to the field of heat treatment of tool steel materials, and in particular relates to a precision heat treatment and quenching process for precision parts of high-carbon chromium ledeburite cold-working tool steel. Background technique [0002] With the upgrading of my country's manufacturing industry, some precision equipment has more and more stringent requirements for parts and components. Domestic materials cannot meet their requirements in some aspects of performance, so relevant advanced imported materials have to be used, especially those from Germany, Sweden and other countries. Pure steel has excellent qualities such as pure, high grain refinement and uniform structure. The import volume has been increasing in recent years, but the heat treatment level is not suitable for it, and it is difficult to exert its performance, resulting in huge waste. Some suppliers have to set up domestic steel. Specialized heat treatment service...

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Problems solved by technology

[0004] The alloy composition of ASSAB XW-5 cold work die steel has a great influence on the heat treatment process, which leads to complex heat treatment process. If the heat treatment is improper, it is not only difficult to exert its excellent performance, but also difficult to control the quality. Therefore, the inventor has declared a heat treatment process. Patent for heat treatment and quenching process for mold steel precision parts (application number 2017112175227), and achieved good results;

[0005] The two knife-edge parts in the precision punching die of electronic connectors are made of ASSAB XW-5 cold-working die steel. In addition to requiring high hardness, good wear resistance, stable size, long life and high reliability, the two knife-edges are also required to have smaller Poor hardness; but high-carbon steel materials have poor thermal conductivity, and the thickness of the workpiece and the alloy composition also have a great influence on the heat treatment process, resulting in complex heat treatment process. If the heat treatment is improper, it is not only difficult to exert its excellent performance, but also difficult to control the quality, and it is easy to be scrapped in batches; general The heat treatment process of cold work die steel is difficult to accurately and reliably control the quenching hardness, and cannot meet the small design hardness difference between the two knife edges of the precision punching die. The holding time during the heat treatment process of workpieces with different thicknesses is usually based on the thickness of the workpiece using the empirical formula t=αКН It is also difficult to reliably guarantee its hardenability and accurately control the uniformity and stability of the internal crystal structure of the material, resulting in creep of the parts during the working process.

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