This paper reports investigations made on the tempering heat treatment effects on steel welds. The properties of the weld investigated were hardness value and toughness. Micro examination of the samples was also done ...This paper reports investigations made on the tempering heat treatment effects on steel welds. The properties of the weld investigated were hardness value and toughness. Micro examination of the samples was also done with optical microscopy. Four (4) different grades of steel rods in 10mm diameter were obtained. The range of the carbon contents of the steel rods was from 0.16 wt% C to 0.33 wt % C. From each grade of the steel materials, grooved specimen of about 150 mm were prepared. The grooves were then filled to create welds using arc welding. A set of the resulting welds were then subjected to tempering heat treatment. The hardness values and toughness of the welds were determined. The microstructural analyses of the welds were carried out as well. The results show that hardness and toughness were dependent on the carbon content. There was also significant microstructural modification due to heat treatment.展开更多
The hardness and residual stress in the forging for cold roller during low temperature tempering,and the relationship of residual stress and cooling temperature of high temperature tempering for heavy forgings were st...The hardness and residual stress in the forging for cold roller during low temperature tempering,and the relationship of residual stress and cooling temperature of high temperature tempering for heavy forgings were studied.The stress relaxation constant at low temperature tempering and the elasto-plastisity inversion temperature at high temperature tempering were found.The results are of great importance to determine rational tempering cooling process of heavy forgings.展开更多
Using a self-made pulse magnetic field heat treatment equipment with low or medium intensi- ty,the tempering process of high speed steel W6Mo5Cr4V2 was investigated.It was found that the secondary hardening process an...Using a self-made pulse magnetic field heat treatment equipment with low or medium intensi- ty,the tempering process of high speed steel W6Mo5Cr4V2 was investigated.It was found that the secondary hardening process and the transformation of retained austenite for the steel were accelerated by the pulse magnetic field,and the tempering period could be reduced to half of the original.It was shown by the analyses of X-ray and eletron microscopy that the precipitation of carbides becomes more homogeneous and dispersive,and the tetragonality of martensite increases obviousely,which causes the improvement of hardness and red-hardness for the steel.It was confirmed that the service life of tools as centre bits,screw taps and punches for nuts could be increased by 0.4 to 1.4 times by the tempering in magnetic field.展开更多
文摘This paper reports investigations made on the tempering heat treatment effects on steel welds. The properties of the weld investigated were hardness value and toughness. Micro examination of the samples was also done with optical microscopy. Four (4) different grades of steel rods in 10mm diameter were obtained. The range of the carbon contents of the steel rods was from 0.16 wt% C to 0.33 wt % C. From each grade of the steel materials, grooved specimen of about 150 mm were prepared. The grooves were then filled to create welds using arc welding. A set of the resulting welds were then subjected to tempering heat treatment. The hardness values and toughness of the welds were determined. The microstructural analyses of the welds were carried out as well. The results show that hardness and toughness were dependent on the carbon content. There was also significant microstructural modification due to heat treatment.
文摘The hardness and residual stress in the forging for cold roller during low temperature tempering,and the relationship of residual stress and cooling temperature of high temperature tempering for heavy forgings were studied.The stress relaxation constant at low temperature tempering and the elasto-plastisity inversion temperature at high temperature tempering were found.The results are of great importance to determine rational tempering cooling process of heavy forgings.
文摘Using a self-made pulse magnetic field heat treatment equipment with low or medium intensi- ty,the tempering process of high speed steel W6Mo5Cr4V2 was investigated.It was found that the secondary hardening process and the transformation of retained austenite for the steel were accelerated by the pulse magnetic field,and the tempering period could be reduced to half of the original.It was shown by the analyses of X-ray and eletron microscopy that the precipitation of carbides becomes more homogeneous and dispersive,and the tetragonality of martensite increases obviousely,which causes the improvement of hardness and red-hardness for the steel.It was confirmed that the service life of tools as centre bits,screw taps and punches for nuts could be increased by 0.4 to 1.4 times by the tempering in magnetic field.
