Study Of Boronizing On The Surface Of Zg1cr18ni9 Stainless Steel

The boronization on the surface of ZG1Cr18Ni9 austenite stainless was carried out using solid powder as boronizing agent.The effects of boronizing temperature,boronizing time,the content of ammonium chlo-ride,as well as catalyzers on the thickness of boride layer were studied. The composition and properties of the boride layer were measured and studied by means of metallographic microscope,scanning electron micros-cope(SEM),X-ray diffractometer and microhardness tester.The thickness of boride layer increased with the increasing boronizing temperature and time.There was not large influence of NH4C1 on the boride layer, and 2% NH4Cl would be the suitable content.Among the three factors of temperature,time and NH4C1,the effect of temperature was larger than the other two.When the addition of KBF4 was 5%,its effete was the best and the boronizing layer was the thickest.The additions of rare earth oxide would damage the boronizing layer and make the layer loosen and broken.It was found that when the addition of NH4Cl was 2%,the boronizing layer was the thickest.When NH4C1 was used as catalyzer, the boronizing layer was denser.The hardness along the boronizing layer decreased from the surface to the center. The surface hardness was 2000HV, inner hardness was 1500HV and the boundary layer hardness was 450～600HV.The brittleness of boroni-zing layer was the 2nd grade,and the brittleness of boundary layer was the 3rd grade.The composition of boronizing layer was single phase FeB.The boron- izing layer showed well corrosion resistant in 10% NaOH solution,but it was not well in 5% H2SO4 solution.