材料的弹性极限是弹簧设计中极为重要的参数，对弹簧的特性有显著影响。针对直径为0.3 mm的阀门弹簧用07Cr17Ni7Al微细丝，通过室温拉伸、单臂弯曲法、光学显微镜、X射线衍射、扫描电镜研究了冷拉拔变形量对丝材强度、弹性极限、弹性后效和微观组织的影响，采用不同数学模型对变形量-马氏体含量、变形量-弹性极限、应力-弹性后效进行了分析。结果表明：固溶态07Cr17Ni7Al丝材由奥氏体和少量铁素体组成，冷拉拔使奥氏体转变为马氏体，随变形量增大，形变诱发马氏体增加。马氏体含量-冷拉等效应变关系符合Olson-Cohen模型，当冷拉等效应变达到1.64时，马氏体含量约92%，形变诱发马氏体达到饱和。丝材的抗拉强度-冷拉等效应变呈线性关系，变形量越大，抗拉强度越高。弹性极限随变形量增大而提高，弹性极限-冷拉等效应变呈“S”形曲线关系，且符合DoseResp模型，当冷拉等效应变达到1.64以上，弹性极限提高程度变小并趋于平缓。弹性后效随应力的提高而增加，符合PWL2模型，存在“弹性后效临界应力”，当应力超过该临界值后，弹性后效随应力增加的速率会提高2~11倍。冷拉等效应变为1.64~2.41时，丝材具有良好的力学性能和弹性性能。

The elastic limit is a critical parameter in spring design， which has a significant impact on the spring characteristic. The influence of cold drawing on the strength， elastic limit， elastic after-effect， and microstructure of 07Cr17Ni7Al ultrafine wire with a diameter of 0.3 mm for valve springs is investigated using room temperature tensile tests， single arm bending method， optical microscope（OM）， X-ray diffraction（XRD） and scanning electron microscope（SEM）. Different mathematical models are used to fit and analyze the deformation and martensite content， deformation-elastic limit， and stress-elastic after-effect. The results show that the solid solution 07Cr17Ni7Al wire is composed of austenite and a small amount of ferrite. Cold drawing transforms austenite into martensite， the content of deformation-induced martensite （DIM） increases with increasing deformation. The relationship between DIM content and cold-drawn equivalent strain （η） conforms to the Olson-Cohen model. When η reaches 1.64， the DIM content is about 92%， and the DIM reaches saturation. The tensile strength of wire exhibits a linear relationship with η， and the larger the deformation， the higher the tensile strength. The relationship between the elastic limit and the η follows an “S” shaped curve and conforms to the DoseResp model. The elastic limit increases with increasing deformation. When the η reaches 1.64 or more， the elastic limit tends to be gentle. The elastic after-effect increases with increasing stress， which conforms to the PWL2 model. There exists a “critical stress for elastic after-effect”. When the stress exceeds this critical value， the rate of elastic after-effect increases by 2-11 times with increasing stress. When the η is 1.64-2.41， the 07Cr17Ni7Al wire has good mechanical and elastic properties.