时效热处理对Fe-Mn-Al-C轻质高锰钢拉伸和冲击性能的影响

The Effect of Aging Treatment on the Mechanical and Impact Properties of Solid Soluted Fe-Mn-Al-C Lightweight High Manganese Steel

摘要:

含铝高锰钢因具有优异的耐磨性、加工硬化能力和低密度特性，作为耐磨器件的关键零配件而被广泛使用，以达到实现轻量化需求和工业节能降耗目的。在ZGMn18Cr2（成分为Fe-18Mn-1.2C-2Cr，质量百分比）的基础上，通过加入质量分数4%的铝，制备出轻质高锰钢。通过光学显微镜（OM）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）、维氏硬度、布氏硬度、摆锤冲击试验和拉伸试验等测试手段，研究了时效热处理对1 100 ℃固溶态轻质高锰钢的组织、硬度、拉伸和冲击等力学性能的影响。结果表明：随着时效温度的升高，经300—500 ℃时效处理后轻质高锰钢的屈强比、硬度及冲击韧性逐渐增强；但经600 ℃时效热处理后，在轻质高锰钢的晶界处析出大量碳化物而形成晶界脆性，最终导致其力学性能恶化，其延伸率和强度急剧降低。

Abstract:

Aluminum-containing high Manganese （Mn） steels are widely used as key parts for wear-resistant devices due to their excellent wear resistance， work hardening ability， and low-density characteristics， in order to achieve the lightweight design and industrial energy-saving and consumption reduction. In the present study， a lightweight high Mn steel with a composition of Fe-18Mn-4Al-1.2C-2Cr （wt.%） is designed by adding the mass fraction of 4% aluminum， and the effect of aging heat treatment on the microstructure， tensile and impact properties of 1 100 ℃ solid soluted steel was studied by optical microscope （OM）， X-ray diffractometer （XRD）， scanning electron microscope （SEM）， hardness test， pendulum impact tests and tensile tests. The results show that the tensile-to-yield stress ratio， hardness and impact energy of the material， after aging between 300 to 500 ℃， increases gradually with the aging temperature. At the same time， the metallographic results show that a large number of carbides were precipitated at the grain boundaries after aging heat treatment at 600 ℃， forming grain boundary brittleness and leading to the deterioration of the mechanical properties of the lightweight high Mn steel， thus elongation and strength of the light-weight wear-resistant steel decreased sharply after aging at 600 ℃.