摘要
利用热膨胀仪、高温共聚焦显微镜和扫描电镜等研究了淬火温度、保温时间和冷却速率等工艺参数对W2Mo9Cr4VCo8高速钢显微组织的影响,并对其硬度和冲击吸收能量进行测试。研究表明,当淬火温度为1100℃时,试验钢中的网状碳化物溶解不充分且分布不均匀;当淬火温度升至1180℃时,奥氏体组织会溶解更多的碳和合金元素,稳定性增强;进一步提高淬火温度至1200℃时,此时高温会引起大量的碳化物发生分解,同时溶入基体的合金元素数量增加,晶粒发生明显长大。当淬火温度在1100~1180℃时,W2Mo9Cr4VCo8高速钢的硬度和冲击韧性随淬火温度的升高而增大,但当淬火温度达到1200℃时,硬度值和冲击韧性减小。当淬火温度为1180℃,保温时间40 min时,钢的硬度达到最高(54.7 HRC),但当保温时间为60 min时,碳化物的平均尺寸增加、数量减少,硬度降低,而冲击韧性随着保温时间的增加而增加,当保温60 min时冲击吸收能量达到22.4 J。随着冷却速率的增加,马氏体转化开始温度(Ms)和结束温度(Mf)降低。因此,高冷却速率可以抑制马氏体转化并增加残留奥氏体含量。
The influences of quenching temperature,holding time and cooling rate on microstructure of W2 Mo9 Cr4 VCo8 high speed steel were studied by means of thermal dilatometer,high temperature confocal microscopy and scanning electron microscopy,and hardness and impact absorbed energy of the steel were tested.The results show that when the quenching temperature is 1100℃,the dissolution of the network carbides in the tested steel is not sufficient and the distribution is uneven;when the quenching temperature rises to 1180℃,the austenite microstructure will dissolve more carbon and alloy elements,and the stability will be enhanced;when the quenching temperature is 1200℃,the high temperature will cause a large amount of carbides to decompose,and the number of alloy elements dissolved into the matrix will increase,and the grain size will grow obviously.When the quenching temperature is between 1100-1180℃,the hardness and impact toughness of the W2 Mo9 Cr4 VCo8 high speed steel increase with the increase of quenching temperature,but when the quenching temperature reaches 1200℃,the hardness value and impact toughness decrease.When the quenching temperature is 1180℃ and the holding time is 40 min,the hardness of the steel reaches the highest(54.7 HRC);however,when the holding time is 60 min,the average size of carbides increases,the quantity decreases,and the hardness decreases.The impact toughness of the steel increases with the holding time,and the impact absorption energy reaches 22.4 J when the holding time is 60 min.With the increase of cooling rate,the martensite transformation start temperature(Ms)and end temperature(Mf)decrease.Therefore,high cooling rate can inhibit martensite transformation and increase the content of retained austenite.
作者
马征
吕广焱
付莹
付连生
郭继宁
张鹏
MA Zheng;Lü Guang-yan;FU Ying;FU Lian-sheng;GUO Ji-ning;ZHANG Peng(School of Engineering,Bohai University,Jinzhou 121013,China;Jinzhou Bo Ruiyuan Innovation Technology Co Ltd,Jinzhou 121013,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2020年第6期121-127,共7页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金青年基金(51704029)。
关键词
高速钢
淬火温度
保温时间
冷却速率
硬度
high-speed steel
quenching temperature
holding time
cooling rate
hardness
