◆ Technological introduction

After it is made in salt bath composite processing, in order to reduce the roughness of the workpiece surface can be a polishing workpiece surfaces, then an oxidation in the salt bath, the precision parts for higher requirements and surface roughness of workpiece is very necessary. In the domestic call it QPQ salt bath composite processing technology. QPQ salt bath composite processing technology, can greatly improve wear resistance and corrosion resistance on the surface of the metal, and almost does not occur deformation, modification technology is a new metal surface strengthening. This technology has realized the nitriding process and oxidation process of compound; Nitrides and oxide compound; Wear resistance and corrosion resistance of composite; Composite heat treatment technology and anti-corrosion technology.

QPQ salt bath composite processing technology is invented by German companies in the 1970 s, after decades of continuous development, application scope is more and more widely, so in a foreign country is considered to be the huge progress in the field of metal surface strengthening technology, called it a new method of metallurgy. Currently, QPQ salt bath composite processing technology in domestic are a large number of popularization and application, especially in the automobile, motorcycle, axial products, electronic parts, textile machinery, machine tools, electrical switches, industry mold use effect is very outstanding.

Mixer technical characteristics

1, good wear resistance

QPQ technology, metal materials under the working temperature of 570 + 10 ℃ react with salt bath liquid, can be in the density of the metal surface to form a layer of fine quality of compound layer. The compound is composed of epsilon iron nitride, completely able to effectively improve the metal surface hardness, density, so that the metal surface with good wear resistance. After processing level of the metal material surface hardness values are mainly depends on the alloy elements in steel, the higher the content of alloy elements, is the higher permeability layer hardness. According to the hardness of high and low permeability layer, can put the commonly used material is divided into the following categories:

(1) carbon steel, low alloy steel

On behalf of the steel grade: 20, 45, TiO, 20 cr, 40 cr, etc. Permeability layer surface hardness: 500-700 hv

(2) alloy steel

On behalf of the steel grade: 3 crw8v, Crl2MoV, 38 crmoal, 1 crl3-4 cr13, etc. Permeability layer surface hardness: 850-1000 hv

(3) the high speed steel and austenitic stainless steel

On behalf of the steel grade: quenching Wl8Cr4V, W6Mo5Cr4V2 and 1 crl8ni9ti permeability layer surface hardness: 1000-1250 hv

(4) cast iron

Permeability layer surface hardness: > 500 hv

Below is 40 cr material of workpiece after different treatments of sliding wear test data, to the wear and tear of QPQ value 0.22 mg as a benchmark, the wear resistance of QPQ technology is 2.1 times hard chrome plating, 2.8 times that of ion nitriding, high frequency quenching of 23.7 times and 29.4 times that of the conventional quenching.

2, good corrosion resistance

Below 45 # steel after QPQ salt bath composite technology, decorative plating chromium, hard chromium plating and ordinary black finish and 1 cr18ni9ti stainless steel and 1 cr13 material after neutral salt spray test. 45 # steel can be seen that after QPQ treatment 1 cr18ni9ti stainless steel corrosion resistance is 5 times, 70 times that of hard chromium plating, but also the 280 times of common black. Other materials after processing the QPQ technology, neutral salt spray test can achieve 100-300 hours.

3, good fatigue resistance

After QPQ salt bath composite processing, the metal surface to introduce and produce a high residual compressive stress, the result is greatly improve the fatigue resistance of various types, after trials show that the fatigue strength can be improved by about 100%, slow down the occurrence of the pit corrosion, rust and other surface defects.

4, tiny deformation

QPQ salt bath composite processing technology because of the low processing temperature, the steel below the phase transformation point, organization transformation, not going to happen so, and have a great organization stress hardening, high frequency quenching, carburizing and quenching and carbonitriding compared hardening process, after processing the workpiece deformation is much smaller. As in 570-580 ℃ after nitriding, artifacts in 350-400 ℃ heat preservation for 15-20 min, it will greatly reduce the artifacts produced in the thermal stress of cooling, so after QPQ salt bath composite processing little deformation of workpiece, is the smallest deformation hardening technology, can effectively solve the conventional heat treatment hardening deformation problem difficult to solve.

5, low carbon environmental protection

Invented the technology company, Germany di high sand because it is German environmental awards. At home, QPQ treatment process by the relevant testing, of the environmental protection department and the actual use by users throughout the country turns out to be harmless, no pollution, do not contain heavy metals. And to replace electroplating heavy process such as pollution.

More than six, alternative process, reduce the time cost

Metal material after QPQ salt bath composite processing, to improve the hardness and wear resistance and improve its resistance to corrosion resistance, so you can take the place of conventional quenching (ion nitriding, high frequency quenching, etc.) a tempering a black (chrome plated), and other multi-channel processes, greatly shorten the production cycle, reduce the production cost. Lots of production data show that the QPQ treatment compared with carburizing and quenching can energy saving 50%, than hard chromium plating cost 30%, cost-effective.

Application range in pieces

1, the most suitable materials:

All kinds of structural steel: blunt iron, Q235, 20, 20 crmnti cr, 20, 20 crnimo, 35 crmo 40, 42 crmo, 45, 50 CRV, 65 mn, cr, 38 crmoal.

All kinds of tool steel: T7 has ~ T12, 5 crmnmo, 5 crnimo, 3 cr2w8v, GCrI5, HI3 (0.35% 1.5% 1.5% C and 5% Cr, Mo, Si, 1% V), Cr12MoV, all kinds of high speed steel.

All kinds of stainless steel: 0 crl3 crl3 ~ 4, 201, 301, 304, 316, 1 cr18ni9ti, 0 crl8nil2moti, 4 cr9si2, 5 cr21mn9ni4n.

All kinds of cast iron, gray iron, malleable cast iron, nodular cast iron, alloy cast iron.

All kinds of iron base powder metallurgy

2, the application of industry:

Automobile, motorcycle, motorcycles, internal combustion engines, textile machinery, engineering machinery, light industry machinery equipment, pump valve, hydraulic machinery, printing and packaging machinery, chemical machinery, electric tools, agricultural machinery, machine tools, tools and moulds, etc, the requirement of high and low voltage electrical switch on the abrasion resistance, corrosion resistance, fatigue resistance, resistance to bite, etc.

3, typical applications:

Engine valve, crankshaft, cylinder liner, gear, CAM, bearing, spindle, slider, steering arm, car wiper ball head shaft, guide rail, hydraulic cylinder, universal joint, connecting pin, all kinds of mould, piston, screw thread screw, bolt and nut, pump body, high speed steel drill bit, barrel, all kinds of knives, flange, key pin, gasket, shell and so on.