Maximizing the Fatigue Strength of a Carburized Helical Gear Via Optimizing Shot Peening Process Parameters-Part 1: Almen Int

Author:  N.S. Chang, R.P. Garibay
Source:  ASME 5th International Power & Gearing Conference
Doc ID:  1989021
Year of Publication:  1989
Abstract:  
Historically, shot peening has demonstrated the potential for substantial increases in fatigue strength. The lack of consistency in reproducing these values in production can be traced to inadequate testwork data behind the process specification and inadequate production process control. The authors present the type of testwork necessary to produce a process specification wherein the optimum parameter nominal values and production tolerances necessary to obtain a minimum fatigue strength value are defined. The use of microprocessor controlled shot peenng equipment to produce specimen conditions representing strategically selected parameter values, and the fatigue testing modes of constant amplitude followed by dynamometer validation are necessary. Depending upon the workpiece characteristics and its workload environment, over a half dozen process parameter nominal values and acceptable tolerances as well as numerous sub-parameters must be defined. This paper will describe Part 1 of the testwork, which is to identify the optimum nominal value of the process parameter called Almen intensity.