The present study aims at developing high speed steel (HSS) as roll materialsto replace traditional roll materials such as the alloy cast iron and powder metallurgical (PM)hard alloy, because low-cost alloy cast iron ...The present study aims at developing high speed steel (HSS) as roll materialsto replace traditional roll materials such as the alloy cast iron and powder metallurgical (PM)hard alloy, because low-cost alloy cast iron rolls have poor wear resistance and the cost ofhigh-quality PM hard alloy rolls is too high to be accepted by some users. By means of a centrifugalcasting method, HSS rolls with excellent wear resistance have been developed. Its hardness is 65-67 HRC, and its variation is smaller than 2HRC; its impact toughness excels 15J/cm^2. Usingpre-finishing stands of a high-speed hot wire-rod rolling mill, the wear rate of HSS rolls per onethousand ton of steel is 0. 25mm. However, the manufacturing burden of HSS rolls is obviously lowerthan that of PM hard alloy rolls; it is only 30% of that of PM hard alloy rolls.展开更多
The microstructure, mechanical properties and wear resistance of high chromium cast steel containing boron after different heat treatments were studied by means of the optical microscopy （OM）, the scanning electron ...The microstructure, mechanical properties and wear resistance of high chromium cast steel containing boron after different heat treatments were studied by means of the optical microscopy （OM）, the scanning electron microscopy （SEM）, X-ray diffraction （XRD）, hardness, impact toughness, tensile and pin-on-disc abrasion tests. The results show that as cast microstructures of boron-free high chromium steel consist of martensite and a few （Cr, Fe）_7C_3 carbide, and the macro-hardness of boron-free high chromium steel is 55-57 HRC. After 0.5 mass% B was added into high chromium cast steel, as-cast structure transforms into eutectic （Fe, Cr）2B, （Cr, Fe）7 （C, B）a and martensite, and the macro-hardness reaches 58-60 HRC. High temperature quenching leads to the disconnection and isolated distribution of boride, and there are many （Cr,Fe）_23 （C,B）_6 precipitated phases in the quenching structure. Quenching from 1050 ℃, high chromium steel obtained the highest hardness, and the hardness of high chromium cast steel containing boron is higher than that of boron-free high chromium steel. The change of quenching temperature has no obvious effect on impact toughness of high chromium steel, and the increase of quenching temperature leads to tensile strength having an increasing tendency. At the same quenching temperature, the wear resistance of high chromium cast steel containing boron is more excellent than that of boron-free high chromium steel. High chromium cast steel guide containing boron has good performance while using in steel bar mill.展开更多
文摘The present study aims at developing high speed steel (HSS) as roll materialsto replace traditional roll materials such as the alloy cast iron and powder metallurgical (PM)hard alloy, because low-cost alloy cast iron rolls have poor wear resistance and the cost ofhigh-quality PM hard alloy rolls is too high to be accepted by some users. By means of a centrifugalcasting method, HSS rolls with excellent wear resistance have been developed. Its hardness is 65-67 HRC, and its variation is smaller than 2HRC; its impact toughness excels 15J/cm^2. Usingpre-finishing stands of a high-speed hot wire-rod rolling mill, the wear rate of HSS rolls per onethousand ton of steel is 0. 25mm. However, the manufacturing burden of HSS rolls is obviously lowerthan that of PM hard alloy rolls; it is only 30% of that of PM hard alloy rolls.
基金Item Sponsored by National Natural Science Foundation of China(51274016)Natural Science Foundation of Beijing of China(2142009)Plan Item of Beijing Education Committee of China(KM201310005003)
文摘The microstructure, mechanical properties and wear resistance of high chromium cast steel containing boron after different heat treatments were studied by means of the optical microscopy （OM）, the scanning electron microscopy （SEM）, X-ray diffraction （XRD）, hardness, impact toughness, tensile and pin-on-disc abrasion tests. The results show that as cast microstructures of boron-free high chromium steel consist of martensite and a few （Cr, Fe）_7C_3 carbide, and the macro-hardness of boron-free high chromium steel is 55-57 HRC. After 0.5 mass% B was added into high chromium cast steel, as-cast structure transforms into eutectic （Fe, Cr）2B, （Cr, Fe）7 （C, B）a and martensite, and the macro-hardness reaches 58-60 HRC. High temperature quenching leads to the disconnection and isolated distribution of boride, and there are many （Cr,Fe）_23 （C,B）_6 precipitated phases in the quenching structure. Quenching from 1050 ℃, high chromium steel obtained the highest hardness, and the hardness of high chromium cast steel containing boron is higher than that of boron-free high chromium steel. The change of quenching temperature has no obvious effect on impact toughness of high chromium steel, and the increase of quenching temperature leads to tensile strength having an increasing tendency. At the same quenching temperature, the wear resistance of high chromium cast steel containing boron is more excellent than that of boron-free high chromium steel. High chromium cast steel guide containing boron has good performance while using in steel bar mill.
