Pitting sensitivity and crack initiation risk of 20CrMnTi gear steel
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摘要: 利用弱腐蝕傾向的溶液環境，控制20CrMnTi鋼產生有限的亞穩態蝕點分布.運用電化學噪聲法，研究了20CrMnTi鋼亞穩態蝕點的萌生規律，結合ANSYS有限元計算，導入真實腐蝕形貌，對比研究了不同腐蝕條件下蝕孔周邊的應力分布與裂紋萌生風險.結果表明，20CrMnTi具有較高的點蝕敏感性，其亞穩態蝕點集中在雜質相邊緣優先形核，隨Cl-濃度的升高，點蝕孕育期明顯縮短，點蝕敏感性增大.不同Cl-濃度下引起的形核速率上升會縮短蝕點間距，表面微裂紋易連接蝕點而發生擴展，增大裂紋萌生風險.Abstract: An environment with a weak corrosion tendency was used to promote the production of a limited metastable pitting distribution in 20CrMnTi steel. The law of metastable pitting initiation was investigated by using electrochemical noise. Using the ANSYS finite element method, the stress distribution and crack initiation risk of holes were analyzed and compared under different corrosion conditions. The results indicate that the pitting sensitivity of 20CrMnTi steel is high. The initiation of metastable pitting is preferentially concentrated at the edge of the impurity phase. The pitting induction period is obviously shortened and the pitting sensitivity increases with an increase in the Cl- concentration. The increase in the nucleation rate induced by different Cl- concentrations reduces the distance between pitting occurrences. Thus, surface microcracks readily connect and propagate pitting, thereby enhancing the risk of crack initiation.
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Key words:
- gear steel /
- pitting /
- electrochemical noise /
- finite element simulation
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參考文獻
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