回火温度对渗碳钢18Cr2Ni4WA组织和硬度的影响

Effect of Tempering Temperature on Microstructure and Hardness of 18Cr2Ni4 WA Carburized Steel

为满足用户加工HBW硬度值≤269的需要,降低18Cr2Ni4WA钢Φ60 mm材硬度,利用连轧厂实际辊底式退火炉进行了630~750℃5 h炉冷至500℃空冷的回火试验,并借助金相显微镜对18Cr2Ni4WA钢不同回火温度下的组织进行了分析,以确定最佳的回火温度。结果表明,18Cr2Ni4WA钢随回火温度的升高硬度先下降后上升,当温度为670℃时,钢材平均HBW硬度值最低(HBW238左右),回火组织为均匀的回火珠光体组织。

In order to meet the user requirement to derease the hardness of 18 Cr2 Vi4 WA steelΦ60 mm product i.e.HBW hardness value≤269,the tempering test at 630~750℃for 5 h,furnace cooling to 500℃,air cooling have been tested by bottom roller annealing furnace and by the help of metalloscope to analyze annealing shape of 18 Cr2 Ni4 WA steel with different temperature.The result show that 18 Cr2 Ni4 WA tempering hardness is connected with temperature,with the increase of annealing temperature,the hardness dacreases first and then increases.When tempering temperature is 670℃,the HBW average hardness of steel products is the lowest(adout HBW238)and the structure is uniform spheroidized pearlite.