Research About Salt Bath Of Nitrogen And Oxygen Permeation On Ring Mode

The essence of the QPQ technology is that it is a process method which do molten salt oxidation, polishing and secondary oxidation after Salt bath nitrocarburizing the material. QPQ technology is a combined treatment. As for the word combine, this tech is a combination of salt bath nitriding and oxidation of salt bath, on the layer structure a combination of nitride and oxide, about the results a combination of wear and corrosion resistance, and technically a combination of heat treatment and corrosion protection. This techonology promises high wear resistance, high corrosion resistance and micro-deformation. Wear resistance could reach more than 10 times as conventional heat treatment dose, corrosion resistance reaches more than 20 times as hard chrome plating dose, and what is more with the minimal deformation of the workpiece.This technology is widely used in industries that require a higher wear resistance, like automotive and mold, widly used around the world, like the US UK France Japan India etc.As one of the most critical equipment of feed processing, ring die pellet mill is is also one the parts which most likely to be weared out. They are now widely dealed with vacuum hardening heat treatment process. But quenching always leads to a larger deformation of the workpiece, and after the quenching calls for the follow-up with the grinding, so to speak, the fee is rather high. At the same time, vacuum quenching ring mold`s surface finish is not enough, in addition to all those, in practical application process sometimes leads to blocking machine. This article will meanly talk about the results, due to the actual situation of ring mode, of the tests of thickness, hardness, wear resistance and other performance on specimens of 40Cr and 3Cr13 materials after nitrogen and oxygen permeation (QPQ treatment). In the end we use optical microscope, XRD-ray diffraction, vickers hardness tester and other equipment to a undergo a full course of detect and analyze on the layer thickness, hardness, wear resistance and other performance indicatorsSamples of the treated layer thickness, hardness, wear resistance and other performance indicators for detection of and at the same time we under go a comparative test between the QPQ sample and vacuum quenched sample and see how they react to friction and wear.With the experiments above,we can see the nitrogen and oxygen permeation salt bath technology surpasses the vacuum heat treatment, and we got to know the best mood of salt bath process of nitrogen and oxygen permeation for 3Cr13. the temperature for salt bath that 3Cr13 needs is 580℃～600℃and the time is 3～4h. And for Salt bath oxidation, temperature is 400℃, the time is 0.5h.