公开(公告)号：US06790294B1

公开(公告)日：2004-09-14

申请号：US09673235

申请日：2000-12-01

申请人： Masaaki Ishida ,  Kazuhiro Uzumaki ,  Yuji Isono ,  Keiichiro Teratoko ,  Yoshiro Yamada ,  Hiroshi Suzuki ,  Hironobu Sasada

发明人： Masaaki Ishida ,  Kazuhiro Uzumaki ,  Yuji Isono ,  Keiichiro Teratoko ,  Yoshiro Yamada ,  Hiroshi Suzuki ,  Hironobu Sasada

IPC分类号： C23C824

CPC分类号： B24C1/086 ,  B24C1/10 ,  C21D7/06 ,  Y10T29/479

摘要： Hard metal particles having hardness which is lower than the hardness of a nitrided outermost layer of a spring and in the range of Hv 500 to 800 and a diameter of 500 to 900 &mgr;m are protected against the nitrided surface of the spring at a velocity of 40 to 90 m/sec to prevent generation of a microcrack in the surface layer and provide a compression residual stress comparatively deep inside the spring. Against the resultant spring surface, a number of fine metal particles having a mean diameter of all particles of 80 &mgr;m or less, a mean diameter of each particle in the range between 10 &mgr;m inclusive and less than 100 &mgr;m, a spherical or near spherical shape with no square portions, a specific gravity of 7.0 to 9.0, and hardness which falls in the range between Hv 600 and Hv 1100 inclusive and is equal to or less than the hardness of the outermost surface layer of the spring after nitriding, at a velocity of 50 to 190 m/sec., while controlling temperature to be low enough to cause work hardening but not to cause softening due to recovery/recrystallization, to provide a high compression residual stress in a near surface layer without generation of microcracks in the surface layer and thus obtain a valve spring and the like excellent in fatigue strength.

摘要翻译： 硬度低于弹簧氮化最外层的硬度，Hv 500〜800，直径500〜900μm的硬度的金属颗粒以40的速度被保护为弹簧的氮化表面 以防止在表面层中产生微裂纹，并且在弹簧内部提供比较深的压缩残余应力。 对于合成的弹簧表面，可以使用平均粒径为80μm以下的各种粒子的平均直径为10μm以上且小于100μm之间的平均粒径为球形或近似球形的许多金属微粒， 没有方形部分，比重为7.0〜9.0，硬度落在Hv600和Hv1100之间，并且在氮化后的弹簧的最外表层的硬度等于或小于速度 50〜190m / sec，同时控制温度足够低以引起加工硬化，但不会由于回复/再结晶而引起软化，从而在表面层中提供高的压缩残余应力，而不会在表面产生微裂纹 从而获得疲劳强度优异的阀弹簧等。