At present, China often use the screw material 45 steel […]
At present, China often use the screw material 45 steel, 40Cr, ammoniated steel, 38CrMOAl and so on.
1) 45 steel cheap, good processing performance, but wear-resistant corrosion-resistant poor performance.
Heat treatment: tempered HB220-270, high-frequency quenching HRC45--48
2) 40Cr better than 45 steel performance, but often have to be coated with a layer of chromium, to improve its corrosion-resistant wear-resistant ability. However, the higher requirements of the chrome layer, the coating is too thin and easy to wear, too thick and easy to peel off, but after the peel into the contrary to speed up the corruption, has less application.
3) Nitrided steel, 38CrMoAl comprehensive superior performance than the more widely used. The general nitride layer of 0.4-0.6 mm. However, this material is resistant to the corrosive nature of hydrogen chloride and its cost is low.
Heat treatment of tempered HB220-270, nitriding HRC> 65
Useful foreign titanium carbide coating method to improve the corrosion resistance of the screw profile, but according to the report, its wear-resistant ability is not enough.
Over the years abroad in the progress of the wear-resistant screw corrosion ability to adopt a series of steps. One approach is to adopt a highly wear-resistant and corrosion-resistant alloy steel. Such as 34CrAlNi ,, 31CrMo12 and so on. There are also adopted in the screw profile spraying with high wear-resistant corrosion resistance of the alloy material.