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What are the surface treatment technologies for molds?

update:11-05-2019
abstract:

Mold is one of the important foundations of modern proc […]

Mold is one of the important foundations of modern processing industry. With the continuous development of mold forming and processing technology, the requirements for mold materials are getting higher and higher.

In addition to the reasonable cooperation of the mold with sufficient strength and toughness, the surface properties of the mold are crucial to the working performance and service life of the mold. These surface properties are: abrasion resistance, corrosion resistance, friction coefficient, fatigue properties, and the like. These performance improvements, relying solely on the improvement and improvement of the matrix material, are very limited and uneconomical, and surface treatment techniques can often achieve twice the result with half the effort, which is why surface treatment technology has developed rapidly.

The surface treatment technology of the mold is to systematically change the morphology, chemical composition, microstructure and stress state of the mold surface by surface coating, surface modification or composite treatment technology to obtain the desired surface properties. From the way of surface treatment, it can be divided into: chemical methods, physical methods, physical and chemical methods, and mechanical methods. Although new treatment technologies are being developed to improve the surface properties of molds, most of the major nitriding, carburizing and hardening film deposits are used in mold manufacturing.

The nitriding process has the methods of gas nitriding, ion nitriding, liquid nitriding, etc. In each nitriding method, there are several kinds of nitriding techniques, which can adapt to the requirements of different workpieces of different steel types. Because the nitriding technology can form a surface with excellent performance, and the nitriding process has a good coordination with the quenching process of the die steel, and the nitriding temperature does not require intense cooling after low nitriding, the deformation of the mold is extremely small, so the surface strengthening of the mold The use of nitriding technology is earlier and the most widely used.

The purpose of mold carburizing is mainly to improve the overall strength and toughness of the mold, that is, the working surface of the mold has high strength and wear resistance. The technical idea introduced here is to reduce the manufacturing costs by replacing the higher-grade materials with lower-grade materials, ie by carburizing and quenching.