基于可测式夏比冲击试验的高硬度钢的动强度

DYNAMIC STRENGTH OF HIGH HARDNESS STEELS BASED ON I NSTRUMENTAL CHARPY IMPACT TEST

通过对不同钢种（优质碳素结构钢S550、高韧性合金结构钢SCM3、高碳铬轴承钢SUJ2、碳素工具钢SK3）的试件材料进行淬火回火等热处理，制备一定硬度范围（HV340～HV860）的高低不同硬度的试件，以此试件作为夏比冲击试验的研究对象。试验的整个过程是在确定冲击载荷测定试验方法的基础上，通过各种不同变形速度的试验，测得不同硬度试件的应力-应变关系曲线，从而测得不同材料的动强度，建立和确认动强度与硬度之间的关系。同时讨论了冲击载荷及其能量吸收的硬度依存性。结果表明，虽然随钢种不同有所差异，但在塑性应变率为100s。左右时的动强度大致高出静强度20％～30％左有；虽然强度随着硬度的增加而增加，但硬度在HV700左右时取最大值；能量吸收的硬度依存性基本以最大弯曲载荷Pmax对应的硬度域为界，硬度越高能量吸收越少；尤其以SUJ2材料的能量吸收为最大。

By quenching and tempering on different steel grade specimen （high quality carbon structural steel S550, high toughness alloy steel SCM3, carbon chromium bearing steel SUJ2, carbon tool steel SK3 ） , preparing a certain hardness range （HV340 - HV860） specimens, those are the study object of the Charpy impact test. The whole testing process is based on impact load measuring test method, through different deformation speed test, measuring the stress-strain curve of different hardness specimen, to obtain the variable strength of different material, establish and confirm the relationship between dynamic strength and hardness. Meanwhile, this paper discussed about the impact load and its energy absorption hardness dependency. The test result shows that although the steel grade is different, but when the plastic strain rate is around 100 s^-1 , the dynamic strength is 20% to 30% higher than the static strength; although the strength is increasing following with the increase of hardness, but when the hardness is around HVT00, get the maximum value; the energy absorption dependency is using the corresponding hardness region of the maximum bending load Pmax as boundary, the higher hardness, the less energy absorption; especially the energy absorption capacity of material SUJ2 is the highest.