QPQ technology completes heat treatment and anti-corrosion treatment at one time, with low treatment temperature and short time. It can improve the surface hardness, wear resistance and corrosion resistance of parts at the same time, reduce the friction coefficient, small deformation and pollution-free. The utility model has the advantages of optimizing the processing procedure, shortening the production cycle and reducing the production cost

QPQ technology is a combination of heat treatment technology and anti-corrosion technology in process, a combination of high wear resistance and high corrosion resistance in performance, and a composite infiltration layer composed of a variety of compounds on the infiltration layer. Therefore, it is considered that this is a great progress in the field of metal surface strengthening technology abroad, and it is called a new metallurgical method

QPQ salt bath composite treatment technology was invented by a German company in the 1970s. After decades of continuous development and improvement, its application scope is becoming wider and wider. Therefore, it is considered as a great progress in the field of metal surface strengthening technology abroad. It is called a new metallurgical method. At present, QPQ salt bath composite treatment technology has also been widely promoted and applied in China, especially in automobiles, motorcycles, shaft products, electronic parts, textile machines, machine tools, electrical switches, tools and molds

2、 Technical features:

1. Good wear resistance

In QPQ process, metal materials react with salt bath liquid at the working temperature of 570 ± 10 ℃, and a dense compound layer with good quality can be formed on the metal surface. The compound is completely composed of ε The composition of iron nitride can effectively improve the hardness and compactness of the metal surface, so that the metal surface has good wear resistance. The surface hardness of the treated metal material mainly depends on the alloy elements in the steel. The higher the amount of alloy elements, the higher the hardness of the carburized layer. According to the hardness of the infiltrated layer, the commonly used materials can be divided into the following categories:

(1) Carbon steel, low platform steel, representative steel grades: 20, 45, TiO, 20Cr, 40Cr, etc. Surface hardness of infiltrated layer: 500-700hv

(2) Representative steel grades of alloy steel: 3crw 8V, Crl2MoV, 38crmoa L, 1crl3-4cr13, etc. Surface hardness of infiltrated layer: 850-1000hv

(3) High speed steel, austenitic stainless steel, representative steel grades: quenched wl8c r4v, w6mo5c r4v2 and 1Crl8Ni9Ti isotonic layer, surface hardness: 1000-1250hv

(4) Cast iron

Surface hardness of infiltrated layer: > 500hv. The following figure is the sliding wear test data of 40Cr workpiece after different treatment methods. Based on the wear value of QPQ of 0.22mg, the wear resistance of QPQ process is 2.1 times of hard chromium plating, 2.8 times of ion nitriding, 23.7 times of high frequency quenching and 29.4 times of normal quenching

2. Good corrosion resistance

The following figure shows the neutral salt spray test comparison of 45# steel with 1Cr18Ni9Ti stainless steel and 1Cr13 material after QPQ salt bath composite process, decorative chromium plating, hard chromium plating and ordinary blackening treatment. It can be seen that the corrosion resistance of 45# steel after QPQ treatment is 5 times that of 1Cr18Ni9Ti stainless steel, 70 times that of hard chromium plating and 280 times that of ordinary blackening. After other materials are treated by QPQ process, the neutral salt spray test can reach 100-300 hours

3. Good fatigue resistance

High residual compressive stress is introduced and produced on the metal surface treated by QPQ salt bath composite process. As a result, the fatigue strength of various types is greatly improved. The test shows that it can improve the fatigue strength by about 100% and slow down the occurrence of surface defects such as pitting and corrosion

4. Minimal deformation

QPQ salt bath composite treatment technology will not undergo structural transformation below the transformation point of steel due to low process temperature. Therefore, compared with hardening processes such as quenching, high-frequency quenching, carburizing quenching and carbonitriding, which produce huge structural stress, the deformation of workpiece after treatment is much smaller. At the same time, after nitriding at 570-580 ℃, the workpiece should be kept at 350-400 ℃ for 15-20min, which will greatly reduce the thermal stress generated during workpiece cooling. Therefore, the workpiece hardly deforms after QPQ salt bath composite process. It is a hardening technology with the smallest deformation, which can effectively solve the problem of hardening deformation that is difficult to be solved by conventional heat treatment methods

5. German digosa company, which invented the process with low carbon and environmental protection, won the German Environmental Protection Award for this process. In China, the QPQ treatment process has been tested and identified by relevant environmental protection departments and proved to be pollution-free, pollution-free and free of heavy metals by users all over the country. It is also used to replace some heavily polluted processes such as electroplating

6. It can replace multiple processes and reduce time cost

After the metal material is treated by QPQ salt bath composite process, it not only improves its hardness and wear resistance, but also improves its corrosion resistance. Therefore, it can replace the conventional multiple processes such as quenching (ion nitriding, high-frequency quenching, etc.), tempering and blackening (chromium plating), which greatly shortens the production cycle and reduces the production cost. A large number of production data show that QPQ treatment can save energy by 50% compared with carburizing and quenching, and save cost by 30% compared with hard chromium plating