Effect Of Ni Content On Structure And Property Of Stainless Steel 0Cr17Ni4Cu4Nb

Stainless steel 0Cr17Ni4Cu4Nb, which obtain strength mainly by the precipitation of copper-rich phase, is a kind of typical precipitation hardened stainless steel. Steels 0Cr17Ni4Cu4Nb of different Ni content were heated with different quenching cooling speed, different aging temperature, and different aging cooling speed. The effect of Ni content on structure and property of stainless steel 0Cr17Ni4Cu4Nb were studied, and the mechanism of Ni content on steel 0Cr17Ni4Cu4Nb was dissussed through the mechanical properties testing, X-ray diffraction analysising, the optical microscope, SEM and TEM observation and analysising. The research Focus on the influence of Ni content on the copper-rich phase, residual austenite andδ-ferrite in steel 0Cr17Ni4Cu4Nb. Obtained the following conclusions:Copper is the main element of stainless steel 0Cr17Ni4Cu4Nb. Large numbers of copper-rich phases,which are tiny and distributing dispersedly,are precipitated in steel after aging. They take strong pinning action on dislocation, and, the smaller and dispersiver of the particles, the stronger of the pinning actin on dislocation. There have a relatively strong influence on the phase transition and gorwing process in aging of copper-rich phase with the improving of Ni content. It reduced the precipitation phase transition temperature of copper-rich phase in the process of quenching, and was in favor of the precipitation of copper-rich phase in the process of aging with the improving of Ni content, which makes strength increased. Controlling Ni content in upper limit is suggested.Ni, which can reduce As and Ms, is a strong austenite forming element. It can reduce the content ofδ-ferrite in steel with the improvement of Ni content.The aging temperature of reversed austenite transition droped, what's more, it obtained more reversed austenite in the same aging temperature with the improvement of Ni content. There have little effect of Ni content and cooling method on the content of residual austenite in steels which aged at 460℃.