QPQ process preheated and two step oxidation to form an oxide film only in the nitriding step deeper penetration of the complex layer.

After the workpiece immersed in a salt bath nitriding , N decomposition of cyanate , C atoms in the surface can be formed with high potential and C N potential . Since the N atom Fe atomic radius is half the radius of the radius of the C atoms is smaller , the N, C atoms may be diffused in the lattice of Fe atoms in the gap .

In the nitriding temperature (510-580 ℃) QPQ treatment , high-concentration N, C atoms to the inside surface diffusion formed in the first α-Fe solid solution . With the increase of the concentration of surface atoms , gradually formed γ '(Fe4N) compound and a compound ε (Fe2-3N). Eventually forming N, C concentration gradient from the surface to the center . Permeation layer is a compound layer with ε , ε -phase + γ ' phase , γ' phase , the following compounds are N layer in the α-Fe solid solution , to form a diffusion layer . Therefore , the workpiece QPQ nitrided layer tissue after treatment by three layers : the outer oxide film ; intermediate compound layer ; inward diffusion layer . Among the most important compound layer , consisting essentially of Fe2-3N, which is guaranteed to improve the wear resistance and reliable , and it is also good corrosion resistance . The main role of the compound is the oxide film constituting the resist layer with an excellent . At the same time it is a porous state , can the oil , to reduce friction , enabling to improve the wear resistance , as well as beautify the appearance . The main role is to enhance the diffusion layer Engineering Fatigue strength member , thin pieces of increased overall strength and flexibility is also a great role.

1 good abrasion resistance , fatigue resistance
This process can greatly improve the surface hardness and wear resistance of parts , reduce the friction coefficient . After QPQ treatment products , wear resistance than conventional quenching and high frequency quenching more than 16 times higher than the 20 # steel carburizing more than nine times higher than the hard chrome plating and ion nitriding more than 2 times . Fatigue tests showed that : the process can improve the fatigue strength of steel more than 40% , compared with ion nitriding , gas nitriding results are good. The process is particularly suitable for complex shape parts , solving key technology to allow deformation problems solved .

(2) good resistance to corrosion
Of several different materials , different samples treated by the same process conditions for the test , according to standard continuous ASTMBll7 spray test , salt spray test temperature of 35 ± 2 ℃, relative humidity of > 95%, 5% NaCL solution spray. The results showed that after the corrosion resistance of parts of QPQ treatment is 5 times 1Crl8Ni9Ti stainless steel , hard chromium plating is 70 times , 280 times is blackened .

3 small deformation after product handling
Workpiece deformation by QPQ almost no treatment after treatment , can effectively solve the conventional heat treatment methods are difficult to solve the problem of deformation hardening . For example: size of 510 × 460 × 2Cr13 stainless steel sheet of 1.5mm was after QPQ treatment, surface hardness greater than HRC60, roughness of less than 0.5mm. Currently , QPQ technology in the shaft parts too numerous , slender rods applications very successful , effective solution to the product deformation hardening and contradictions exist have been heat treated .

4 can replace the multi-channel heat treatment and anti-corrosion treatment step , a short period of time
After the workpiece QPQ treatment , to improve its hardness and wear resistance while improving on the basis of its corrosion resistance , and the formation of black , beautiful appearance , can replace a conventional quenching and tempering a black ( chrome ) , and other procedures shorten the production cycle, reduce production costs. A lot of production data show , QPQ treatment and case hardening can save 50% compared to hard chrome plating than 30 percent cost savings , cost-effective .

5 . Pollution level is high, no environmental pollution
QPQ treatment process identified by the relevant environmental protection department , and by the actual use of users throughout the country prove harmful substances emissions are lower than the national emission standards for allowable value. Due to advanced technology, stable quality , QPQ technology there are hundreds of different kinds of products .

Applicable to a wide range of materials technology 6.QPQ
The process for all iron, stainless steel materials are suitable , from pure iron , mild steel, structural steel , tool steel to a variety of high-alloy steel , stainless steel, cast iron and iron-based powder metallurgy .

Nitriding process refers to a certain temperature at a certain media manipulation nitrogen atoms into the workpiece surface chemical heat treatment process. After nitriding treatment products with excellent wear resistance , fatigue resistance , corrosion resistance and high temperature properties .

The main difference is the soft liquid nitrogen in the nitride layer has Fe3Nε phase , Fe4Nr phase with the presence of free Fe2Nξ nitride , ξ phase compounds in the nitriding process is hard and brittle ductile bad nitride liquid tufftride the workpiece is to be processed , the first descaling, degreasing , and then placed in a preheated nitride crucible crucible TF-1 is a salt -based agents, is heated to 560 ~ 600 ℃ processed to a number of hours , depending on the size of the work load of the external force , but decided nitride layer depth , in the process , it must pass into the bottom of the crucible in an air duct to the air a certain amount of salt nitriding agent is decomposed into CN or CNO, penetration and diffusion to work surface, so that the outermost surface compound 8 ~ 9% wt and a small amount of C and N diffusion layer diffuses into the nitrogen atom manipulation α-Fe base steel is more resistant to fatigue due to the consumption during the decomposition of nitrogen CNO , so continue to test the salt agent into 6 to 8 hours treatment

Parts , in order to adjust the amount of air or adding new salt agent.

Liquid nitriding soft iron material is treated with a metal , the surface hardness after nitriding containing Al, Cr, Mo, Ti element by high hardness , and the more its gold content and more shallow depth of nitride , such as carbon steel Hv350 ~ 650 stainless steel Hv1000 ~ 1200, nitrided steel Hv800 ~ 1100.

Soft liquid nitrogen for wear and fatigue resistance and other auto parts , sewing machines , cameras, etc. , such as cylinder liner treatment, gas treatment patriarch , dies at the piston cylinder handling and easily deformed .

Su's heat treatment Co. Ltd. was founded in 1990, after decades of development, scale is continually expanding, is located in Shajing Town Baoan District Shenzhen City Bridge second industrial zone, covering an area of 3000 square meters, the main business is to take all the metal, alloy steel, beryllium copper, heat treatment of high speed steel, cryogenic treatment (-196 C), nitrogen gas, liquid nitrogen, QPQ salt bath production line, high-frequency quenching, blackening and carburizing, the surface of hard and stainless steel processing.
The company is equipped with power of heat treatment technology, established a perfect quality testing equipment, equipped with vacuum quenching furnace, vacuum furnace, pit furnace, furnace, liquid nitrogen atmosphere furnace, rotary furnace, large mesh belt furnace, improve metallographic inspection equipment, material failure analysis, scientific management and complete, rigorous technology, skilled operation.
Company will be excellent quality and perfect service, and actively challenge, satisfy customer demand, has passed ISO9001:2000 in 2003 September (SGS) international quality certification. Has now become a reputable manufacturers.