Fatigue strength and fracture mechanisms in severely drawn eutectoid steel wires

严重拉拔共析钢丝的疲劳强度和断裂机制

• 批准号: 09650086
• 负责人: KATAGIRI Kazumune
• 金额: $ 2.11万
• 依托单位: Iwate University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650086/
• 关键词: Fatigue strength; Eutectoid steel wire; fatigue crack growth; Drawing strain; Residual stress; Hardness; Bluing; Shot-peening; 共析鋼極細線; ショット ピーニング; 共析鋼; 極細線材; 疲労き裂進展抵抗; 線径; ラメラ間隔

Following results clarifying the effects of various factors on the fatigue strength of eutectoid steel wires were obtained through the experiments.1. Within the drawing strain range of epsilon 0 to 3.8, fatigue strength increased monotonically up to 800MPa with increase in epsilon , as in the case of ferritc steel in which the degree of increase is low. In some cases, however it had a peak value at epsilon=2.5 depending on the fabrication condition. It increased with decrease in the wire diameter and did not depend on the lamellar spacing (0.01-0.02 mu m).2. Associated with high density dislocations and the narrow lamellar spacing observed in TEM, the hardness and tensile residual stress in the surface layer increased with increase in epsilon up to Hv=520 and 1000 MPa.3. While the tensile residual stress monotonically decreased with increase in bluing temperature and diminished at 500ﾟC, the hardness increased to a peak value of Hv=650 by bluing at 300ﾟC The fatigue limit increased to a peak of 900MPa by bluing at 400ﾟC due to combined effects of strain aging, recovery and relaxation of residual stress. By shot peeing, the residual stress decreased from 1000 to -300 MPa and the highest fatigue limit of 1200 MPa was obtained4. Fatigue crack initiated from inclusions or the ferrite layer in the surface region and changed its direction at the boundary of pearlite colony. The ratio of the duration for fatigue crack initiation in the fatigue life-time increased with increase in epsilon5. With increase in epsilon , the *K_<th> decreased through decrease in the roughness induced crack closure level due to decrease in the pearlite colony size. The fatigue crack resistance in Paris' region also increased and the "m-value" decreased.

以下结果阐明了各种因素钢丝电线的疲劳强度，获得了实验。1。在某种程度上，霍维尔的峰值在某种程度上是epsilon = 2.5的峰值随着密度位错和在TEM中观察到的窄层间距，表面层随着EPSILON的增加而增加，直至HV = 520和1000 MPa.3通过在300°C C上融合，由于流浪的综合效应，疲劳极限增加到了400个峰值，从1000 mPa降低到-300 MPa，并获得了1200 MPa的最大疲劳限制。珍珠颜色的边界“ M值”下降。

项目成果

佐藤正: "共析綱極細線の疲労強度に及ぼすブルーイングの影響" 日本機械学会論文集(A編). 64・626. 74-79 (1998)

佐藤正：“发蓝对超细共析线疲劳强度的影响”日本机械工程学会会刊（ed.A）64・626（1998）。

K.Katagiri: "Effects of Drawing Strain and Bluing on the Fatigue Strength of Eutectoid Steel Wires" Fatigue & Fracture of Engineering Materials & Structures. 20・12. 1677-1686 (1997)

K.Katagiri：“拉拔应变和发蓝对共析钢丝疲劳强度的影响”《工程材料与结构的疲劳与断裂》20・12（1997）。

K.Katagiri, T.Sato, K.Kasaba, et al: "Effect of post drawing treatments on fatigue strength of eutectoid steel wires" Fatigue Fract.Engng.Mater.Struct.(accepted). (1999)

K.Katagiri、T.Sato、K.Kasaba 等人：“拉拔后处理对共析钢丝疲劳强度的影响”Fatigue Fract.Engng.Mater.Struct.（已接受）。

K.Katagiri, T.Sato, H.S.Shin, et al: "Effect of drawing strain and bluing on the fatigue strength of eutectoid steel wires" Fatigue Fract.Engng.Mater.Struct.Vol.20, No.12. 1676-1686 (1997)

K.Katagiri、T.Sato、H.S.Shin 等人：“拉拔应变和发蓝对共析钢丝疲劳强度的影响”Fatigue Fract.Engng.Mater.Struct.Vol.20，No.12。

佐藤正: "共析鋼極細線の疲労強度に及ぼすブルーイングの影響" 日本機械学会論文集(A編). 64・626. 74-79 (1998)

佐藤正：“发蓝对超细共析钢丝疲劳强度的影响”日本机械工程学会会刊（ed.A）64・626（1998）。