Accurate heat treatment quenching technology for ordinary chromium-molybdenum hubbing steel precision components

Abstract

The invention mainly discloses an accurate heat treatment quenching technology for ordinary chromium-molybdenum hubbing steel precision components. The material is Sweden imported high-purity ordinarychromium-molybdenum hubbing steel ASSAB XW-10, and main alloy components of the high-purity ordinary chromium-molybdenum hubbing steel ASSAB XW-10 include 1.0% of C, 5.3% of Cr, 0.8% of Mo and 0.8% of V. According to the main steps and the technical scheme, firstly, workpieces with the thickness difference smaller than 5 mm are placed in a quenching furnace to be preheated two times, preheating is conducted to 100 DEG C at the heating speed smaller than 75 DEG C / h the first time, and preheating is conducted to 150 DEG C at the heating speed smaller than 115 DEG C / h the second time; secondly,two-level heating is conducted in the quenching furnace till the quenching temperature reaches 960 DEG C, and heat preservation is conducted; thirdly, the workpieces are discharged out of the furnaceand placed on a support, an air blower is opened, and the workpieces are subjected to air cooling to 50-70 DEG C; and fourthly, the workpieces are placed in a tempering furnace two times to the temperature of T DEG C, heat preservation and tempering are conducted, furnace discharging air cooling is conducted to the room temperature, and please see the attached figure 1. According to different workpiece thicknesses and different hardness requirements, the accurate heat treatment temperature and time technology parameters are adopted so that material inner structure changes, carbide precipitation forms and grain growth can be accurately controlled, accordingly, retained austenite is eliminated, ultra-fine carbide is precipitated, grain refining and structure uniformity are kept, accurate component hardness is achieved, creep deformation is avoided in the usage process, and size stability and high abrasion resistance are kept.

Description

technical field [0001] The invention belongs to the field of heat treatment of die steel materials, and in particular relates to a precise heat treatment and quenching process for two knife-edge parts in a precision punching die. 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; ASSAB XW-10 is a Swedish brand, and its The main alloy composition is 1.0%C 5.3%Cr 0.8%Mo 0.8%V. It has high purity and uniform grain refinement, which is similar to American AISI A2 and Chinese Cr6WV1. The commonly used quenching hardness is HRC56-HRC61; the steel has good Air quenching performance and hardenability, fine and uniform distribution of carbides, very little residual austenite and residual stress, small heat treatment size ...

AI Technical Summary

Problems solved by technology

[0003] Chromium-molybdenum stamping die steel has 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 a complex heat treatment process. If the heat treatment is improper, it will not only make it difficult to exert its excellent performance, but also show a certain degree of high temperature tempering brittleness, and the quality is difficult to control. For this reason, the inventor has applied for a heat treatment and quenching process patent for chromium-molybdenum die steel precision parts (application number 2017112188640), which has achieved good results;

[0004] Semiconductor chip precision packaging molds are more complicated in the use process due to the force of the mold. Some working parts of the mold need to have some special mechanical properties. The parts have precise hardness requirements and higher impact dimensional stability, damage resistance, and reliability. If the standard heat treatment process is often unable to meet the ideal working performance requirements, it is necessary to properly adjust the basic properties such as hardness, toughness and wear resistance through heat treatment to achieve the best working state of the mold, quenching temperature and tempering temperature It is the main process parameter of heat treatment, and the thickness of the parts is different. According to the thickness of the workpiece, use the empirical formula t=αКН to estimate the holding time in the heat treatment process. Not only is it difficult to accurately and reliably control the quenching hardness, but it is also difficult to accurately and reliably control the internal Changes in the crystal structure and thermal instability of a small amount of retained austenite lead to creep during the working process of the parts, making it difficult to meet the requirements of use; this requires precise heat treatment temperature and Time process parameters to precisely control the internal structure changes, carbide precipitation, grain growth to ensure very little retained austenite and residual stress

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