PS6 ショットピーニング条件が高強度鋼の無害化可能な表面欠陥寸法に及ぼす影響(フェロー賞対象ポスターセッション)

概要

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Effects of shot peening condition (shot diameter) on the bending fatigue strength and acceptable surface defect size were investigated for spring steel specimens containing an artificial small drilled hole. Shot peening was carried out using 0.3mm shot (0.3SP) and 1.0mm shot (1.0SP) on the specimens containing a drilledhole which depth was 0.05, 0.1, 0.2 ,03 and 0.4 mm. Then, bending fatigue tests were conducted on the specimens. As a result, the fatigue strength of 0.3SP specimens and 1.0SP specimens was improved substantially because of the compressive residual stress generated on the surface. The 0.3SP specimens with a hole which depth was under 0.05mm fractured outside the hole. The 1.0SP specimens with a hole which depth was under 0.2mm fractured outside the hole. In addition, SP specimens had considerably high fatigue limits almost equal to those of the shot peened smooth specimens. Therefore, h=0.05mm diameter drillhole was acceptable in the case of 0.3SP. In the same way, h=0.2mm diameter drill hole was acceptable in the case of 1.0SP. It was found that acceptable surface defect size depends on the residual stress distribution.
2010-10-09