摘要
研究了ＧＣｒ１５钢淬火不同温度回火后扭转流变硬化行为、组织和强度的关系。研究表明，在双对数坐标上硬化曲线呈现多ｎ行为。在低于２５０℃回火，随回火温度降低，诸ｎ值增大的原因很多，但残余奥氏体及其塑变诱导相变强化效应在其中起着主要作用。在高温回火范围，随回火温度降低，诸ｎ值减小的原因与渗碳体质点间距，即位错运动平均自由程（ＭＦＰ）有关。尽管宏观扭转断口有正断和切断之分，但微观断口均为韧窝，这表明塑变和硬化在断裂过程中起着重要作用。据此，可借助τ（０．３）、γｋ和ｎｌ值的变化分析τｋ值随回火温度变化的规律。
The relafionship between the torsional flow behaviour and the structure strength of tempered GCr15 steels was studied in this paper. Multiple n behaviour was observed in the hardening curve when used double logarithmic coordinate axis. If the temperature is lower than 250℃, the n values increase with the decrease of tempering temperature. in high temperature tempering the n values decrease with the decrease of tempering temperature. When tempered under medium temperature the n values is the lowest in all of the tempering states. Although the torsional macro fracture possesses two type of fracture modes ──positive fracture or shear fracture, yet the microfracture appearance is always dimples. This illustrates the major effect of plastical deformation and hardening in fracture prossess. Accordingly the cause that the slow decrease of τk value is associated with the of raise tempering temperature can be overall recognized through the change of τ0.3、τk and n valnes.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
1994年第5期94-99,共6页
Journal of Mechanical Engineering
基金
国家自然科学基金
关键词
高碳钢
应变
硬化
调质处理
回火
High-carbon steel Strain Hardening Quenchiug and temperingStructure
