screw root 中文意思是什麼
screw root
解釋
螺桿中心軸-
Abstract : by means of metallographical examination and sem, the microstructure characteristics, macro - and microfractographs of the brittle broken wheel hull bolt of bj212 automobile have been studied. the results show that the thin - headed screw, with excessively deep carbonitriding layer and hardening layer, has less resistance to brittle fracture in the thin area of its head. at the root of the head connecting the stem, a tensile stress may emerge owing to the non - even quenching stress. those are the two reasons for low torque fracture of bolt
文摘:藉助金相、掃描電鏡等手段對低扭矩脆斷的bj212汽車輪殼螺栓的金相組織特徵，宏觀和微觀斷口形貌等進行了研究，結果表明：這種頭部薄的螺栓，滲層和淬透層過深，使頭部薄區脆斷抗力降低，在頭部與桿的根部，由於淬火應力不均勻導致根部產生拉應力，均是導致螺栓低扭矩斷裂的原因。 -
The fatigue fracture occurred in the root of the screw where defects such as decarburization and cracks existed, and these defects made the zone to be a stress concentration area and caused the bolts to break finally
疲勞裂紋的形成是由於螺紋牙底存在脫碳和折疊裂紋等缺陷，這些缺陷的存在使該材料產生了較大的應力集中，從而導致螺栓開裂失效。
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