Local ion nitriding method for inner cavity of precipitation-hardening stainless steel annular part

The invention relates to a local ion nitriding method for an inner cavity of a 05Cr17Ni4Cu4Nb precipitation hardening stainless steel annular part. The method comprises the following steps: designing an anti-seepage tool, protecting the outer surface of a part and the part, which does not need to be nitrided, of an inner cavity, putting the part into an ion nitriding furnace, introducing nitriding gas, controlling the gas flow, adjusting electrical parameters in the nitriding process, raising the temperature in the furnace to the required nitriding temperature, keeping the temperature at the nitriding temperature, and slowly cooling. By means of the method, the hardness and depth of a nitriding layer of the part, needing nitriding, in the 05Cr17Ni4Cu4Nb precipitation hardening stainless steel annular part meet the technical requirements, and no nitriding layer exists on the other parts under protection of a tool; and the matrix hardness is not changed. 本发明涉及一种05Cr17Ni4Cu4Nb沉淀硬化不锈钢环形零件内腔局部离子渗氮的方法。内容包括设计防渗工装，将零