【摘要】 利用温压缩实验,在Gleeble-3500热力模拟试验机上测定了中碳钢马氏体(M)和铁素体+珠光体(F+P)两种组织的流变曲线。对比研究了应变速率对这两种组织流变行为的影响。结果表明:在相同温度下,M组织的应变速率敏感性指数(mM)和加工软化率(sM)都大于F+P组织的相应参数(mF+P)和(sF+P)。应变速率为0.001 s-1,变形温度为600℃、650℃、700℃,M组织的流变曲线均低于F+P组织的流变曲线;当应变速率从0.01 s-1增加到10 s-1,M组织和F+P组织的流变曲线相交,交点应变为临界应变,大于临界应变,M组织的流变应力低于F+P。这表明,对降低钢材温轧或零件温挤压的变形应力和成本来说,M组织可能比F+P更好。此外,对导致M组织上述流变行为的机理进行了初步探讨。更多还原

【Abstract】 Flow curves of warm deformation performed on martensite structure(M) and ferrite plus pearlite structure(F+P) in a medium carbon steel were determined on Gleeble-3500 machine.Comparison study was conducted on effect of strain rate on the warm low behavior of two starting microstructures of M and F+P at various temperatures.It is found that the strain rate sensitive index(mM) and working softening rate of sM of M are larger than that of F+P,(mF+P) and(s F+P).And the flow stress of M is lower than that of F+P under the conditions of strain rate of 0.001s-1 and deformation temperature at 600℃,650℃ and 700℃.When the strain rate ranges from 0.01s-1 to 10.0s-1,there are critical strain values at which the M flow curves intersect the F+P curves under some conditions.In these cases,if the strain amount is larger than the critical strain,the martensitic flow stress is lower than that of F+P.These results show that,M structure,compared with F+P structure,may be a promising candidator for steel’s warm working.Additional,the mechanism results in these characteristics of M flow behavior are also discussed.更多还原