Microstructures and properties of 17-4PH stainless steel by laser hybrid hardening

作者：Yao Jian Hua^*; Dai Jun Hao; Kong Fan Zhi; Zhang Qun Li; Wang Wei Fu; Guo Shi Rui

来源：Optics and Precision Engineering, 2011, 19(SUPPL.2): 177-185.

• 17-4 PH stainless steel
• Cavitation resistance
• Equiaxial grains
• Hybrid hardening
• Laser alloying
• Laser surface
• Microstructures and properties
• Scanning electronic microscopy
• Solid solution strengthening
• Top surface
• Transition zones
• Work pieces

Laser surface hybrid hardening was performed on a 17-4PH stainless steel workpiece by two laser beams. A deep strengthened layer with an alloyed zone on the top surface and a solid solution zone on the subsurface was obtained. The results of Scanning Electronic Microscopy (SEM), X-ray Diffractometry (XRD), microhardness and cavitation testing on the strengthened layer show that the microhardness of the laser alloyed zone slightly decreases after aging because of part decomposition of the intermetallic (Al0.28Co0.4Cr0.24W0.08), while the deposition of precipitation hardening phases makes the microhardness of the laser solid solution zone obviously increase. The microhardness of strengthened layer drops in gradient from top to bottom with an average microhardness of 435 HV0.2, which is 30% higher than that of the substrate. The depth of the strengthened layer is more than 1.5 mm and the cavitation resistance is 100% higher than that of substrate. Caused by the secondary heating of laser alloying beam, the bulky and equiaxial grains and serious composition segregation make the transition zone appear softening.

• 出版日期2011
• 单位浙江大学