摘要
对商用25Cr2NiMo1V钢进行了955℃淬火+665℃回火的高压端热处理(HP)和900℃淬火+625℃回火的低压端热处理(LP).通过疲劳实验测定了HP与LP试样疲劳门槛值和疲劳裂纹扩展速率.结果表明,在门槛值区,HP试样门槛值高于LP试样,而其裂纹扩展速率却低于LP试样,HP试样抵抗疲劳裂纹扩展能力高于LP试样.材料抗疲劳裂纹扩展能力的不同是由裂纹的闭合引起的,表面粗糙度诱发裂纹闭合为主要因素.HP试样中回火贝氏体的紧密分布,原始奥氏体晶粒较大以及LP试样中回火马氏体抵抗裂纹扩展能力相对较弱使HP试样中粗糙度诱发裂纹的闭合程度大于LP试样.在Paris区.HP与LP试样的扩展速率相近,裂纹扩展速率对材料微观组织和应力比的影响不敏感.
The specimens of commercial 25Cr2NiMo1V steel were treated at 955 ℃ quenching ＋665 ℃ tempering （HP） and 900 ℃ quenching ＋625 ℃ tempering （LP）, respectively. Fatigue threshold and fatigue crack propagation rate tests were conducted in HP and LP specimens. The results show that in threshold regime, the HP specimen has larger fatigue threshold and lower fatigue crack growth rates than the LP specimen. The fatigue behavior is related to crack closure and the surface roughness is a main factor for crack closure. HP specimen has a larger crack closure ability than LP specimen due to the densified bainites and larger prior austenite grain size. HP specimen has more tempering martensites which do not play an important role in preventing crack growth. In Paris regime, no clear difference between fatigue behaviors of HP and LP specimens is observed.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第3期320-325,共6页
Acta Metallurgica Sinica
基金
国家高技术研究发展计划项目2006AA04Z413
教育部新世纪优秀人才计划项目NCET-06-0414资助~~
