On microstructure and performance of tempered high-boron high-speed steel roll

• 作 者: Fu Hanguang Du Zhongze Li Ping
• 机 构: School of Materials Science and Engineering,School of Metallurgical Engineering,Yunnan Kun-Steel Hea
• 出 处: 中国铸造
• 发表日期: 2004年期
• 关键词: high boron high speed steel tempering temperature carbo-boride metallic matrix m
• 基金项目: Science and Technology Cooperating Project of Yunnan Province,China;国家自然科学基金;The study was financially supported by the Scientific Plan Project of Beijing Education Committee

Influences of the tempering temperature on the microstructure,mechanical property and wear resistance of High-Boron High Speed Steel (HBHSS) roll materials were investigated by means of optical microscopy,scanning electron microscopy (SEM),X-ray diffraction,hardness measurement,impact tester,tensile tester and pin abrasion tester.The results show that the as-cast structure of HBHSS consists of a great amount of martensite and M2(B,C) and a few retained austenites and M23(B,C)6.After solution treated at 1,050 ℃ and followed by oil cooling,the amount of M23(B,C)6 carbo-borides in quenched HBHSS increases obviously and the macrohardness of the quenched HBHSS is 66 HRC,which is very close to the 65.8 HRC of as-cast HBHSS.On the whole,the hardness of HBHSS alloy shows a trend of slight decrease with increasing tempering temperature when tempered below 500 ℃.While when above 500 ℃,the hardness increases slightly as the tempering temperature increases and reaches a peak at 525 ℃ and then decreases obviously.The impact toughness of HBHSS has a tendency to increase as the tempering temperature increases.Tempering can improve the tensile strength and elongation of HBHSS,but a higher tempering temperature causes a slight decrease in both tensile strength and elongation.Excellent wear resistance can be obtained by tempering at 500 to 550 ℃.