表面技术2016，Vol.45Issue(7)：17-21,5.DOI:10.16490/j.cnki.issn.1001-3660.2016.07.003
中温时效对17-4PH不锈钢液体氮化后组织性能的影响
Effect of Mid-temperature Aging on the Microstructure and Properties of 17-4PH Stainless Steel after Liquid Nitriding
摘要
Abstract
ABSTRACT:Objective To study the change of the microstructures and properties of 17-4PH stainless steel after low temper-ature salt bath nitriding treatment and mid-temperature aging treatment.Methods The thickness and microstructure of the ni-triding layer were analyzed using optical microscope (OM) , the phase composition of the nitriding layer was determined by X-ray diffractometer (XRD), the hardness of the nitriding layer was measured by microhardness tester, and the corrosion resis-tance of the nitriding layer was evaluated by erosion-corrosion experiment.Results The thickness of the nitriding layer in- creased with the extension of aging time. The change of nitrogen concentration in nitriding layer during the aging treatment re-duced Gibbs free energy. This led to decomposition of expanded supersaturated austeinite into Fe4N with face-centred cubic structure. When it went up to a certain concentration, some Fe2N precipitated out. The decomposition rate of expanded auste-inite increased with rising temperature. Then, extension of aging time and rise of aging temperature promoted CrN to sepa-rate out. The depth of the nitrided layer was increased to 27.4μm; The active energy of nitrogen-atoms in 17-4PHstainless steel was 216.2 kJ/mol ascalculated form Thermodynamics formula; The surface microhardness significantly increased to nearly 1150HV0.1, and then gradually reduced; The erosion-corrosion mass loss rate of 17-4PH stainless steel reached its maximum value of 30.3 mg/(h·dm2) after 50 days of 475℃ aging treatment.Conclusion17-4PH stainless steel after nitriding could reach its maximum surface hardness after aging treatment at 425~475℃ for some time. Then, with the increasing aging time, its surface hardness and erosion-corrosion resistant performance reduced.关键词
17-4PH不锈钢/低温液体氮化/时效/显微硬度/激活能/冲刷腐蚀性能Key words
17-4PH stainless steel/low-temperature liquid nitriding/aging treatment/microhardness/activation energy/erosion-corrosion performance分类
矿业与冶金引用本文复制引用
王佳薇,王均,鲜广,李明星,范洪远..中温时效对17-4PH不锈钢液体氮化后组织性能的影响[J].表面技术,2016,45(7):17-21,5.基金项目
国家自然科学基金（51471112） FundSupported by the National Natural Science Foundation of China (51471112) （51471112）
