参照4Cr5Mo2V热作模具钢的化学成分，制备了钒质量分数分别为0，0.55%和0.9%的试验钢，并进行了表面离子渗氮处理，研究了钒含量对渗氮后热作模具钢组织和性能的影响。结果表明：3种试验钢的基体组织均为马氏体，渗氮层主要由白亮层和扩散层组成；随着钒含量提高，试验钢基体组织明显得到细化，白亮层分布变得连续，扩散层厚度先变大后减小，当钒含量为0.55%时，基体组织最细小，扩散层最厚；添加钒后，扩散层中出现弥散分布的富含碳、氮、铬、钒元素的细小颗粒状析出相，随着钒含量提高至0.9%，析出相数量减少，尺寸增大；试验钢的表面硬度和耐磨性随钒含量提高先提高后降低，当钒含量为0.55%时，表面硬度最高，为1 287.3 HV，摩擦因数最低，为0.15，磨损机制为磨粒磨损。

Referring to the chemical composition of 4Cr5Mo2V hot-work die steel, test steels with V mass fraction of 0, 0.55% and 0.9% were prepared, and surface ion nitriding treatment was carried out. The effect of V content on the microstructure and properties of hot-work die steel after nitriding was studied. The results show that the matrix structures of three test steels were all martensite, and the nitriding layer was mainly composed of white bright layer and diffusion layer. With increasing V content, the matrix structure of test steel was obviously refined, the distribution of white bright layer became continuous, and the thickness of diffusion layer first increased and then decreased. When the V content was 0.55wt%, the matrix structure was the finest and the diffusion layer was the thickest. Fine granular precipitates rich in C, N, Cr and V appeared in diffusion layer after added V. As the V content increased to 0.9wt%, the number of precipitates decreased and the size increased. The surface hardness and wear resistance of test steels increased first and then decreased with increasing V content. When the V content was 0.55wt%, the surface hardness was the highest, 1 287.3 HV, the friction coefficient was the lowest, 0.15, and the wear mechanism was abrasive wear.