Influence of Ti on MC carbide of M2 high speed steel was investigated by experimental observation, thermodynamic calculation and crystallographic calculation. With addition of Ti into M2 steel, large quantities of dis...Influence of Ti on MC carbide of M2 high speed steel was investigated by experimental observation, thermodynamic calculation and crystallographic calculation. With addition of Ti into M2 steel, large quantities of dispersed TiC particles formed in the steel melt at higher temperature than that of the formation of MC carbide. TiC can act as heterogeneous nuclei for the crystallization of MC carbide particles, and therefore promote the formation of blocky MC carbide.展开更多
Microstructure and impact toughness in the coarse grain heat-affected zone (CGHAZ) of HQ130 high strength steel were studied by using the weld thermo-simulation test. Fracture morphology and fine structure in the CGHA...Microstructure and impact toughness in the coarse grain heat-affected zone (CGHAZ) of HQ130 high strength steel were studied by using the weld thermo-simulation test. Fracture morphology and fine structure in the CGHAZ were analyzed by means of SEM, TEM and electron diffraction. Experimental results indicated that the impact toughness and hardness in the CGHAZ (T-m = 1350 degrees C) decreased with increasing cooling time (t(8/5)), and fracture morphology changed from dimple fracture into cleavage fracture. The reason for the toughness decrease is the formation of upper bainite. During application, the welding heat input should be strictly limited, to reduce brittleness in the CGHAZ of HQ130 steel.展开更多
Microstructure, precipitates and fracture morphology in the weld metal and he heat-affected zone (HAZ) of Cr18Mo2 ferritic stainless steel have been studied by means of metalloscope, SEM, TEM and X-ray diffractometer....Microstructure, precipitates and fracture morphology in the weld metal and he heat-affected zone (HAZ) of Cr18Mo2 ferritic stainless steel have been studied by means of metalloscope, SEM, TEM and X-ray diffractometer. Experimental results indicate that crystalline grain coarsening in HAZ is one of the reason resulting in the embrittlement fracture in the welding zone of the Ferritic stainless steel. Some precipitates (TiC, TiN and Cr2N) in the steel promote production and development of the brittle cracks. in practical applications, the welding heat input should be as small as possible to prevent embrittlement caused by HAZ grain coarsening.展开更多
文摘Influence of Ti on MC carbide of M2 high speed steel was investigated by experimental observation, thermodynamic calculation and crystallographic calculation. With addition of Ti into M2 steel, large quantities of dispersed TiC particles formed in the steel melt at higher temperature than that of the formation of MC carbide. TiC can act as heterogeneous nuclei for the crystallization of MC carbide particles, and therefore promote the formation of blocky MC carbide.
文摘Microstructure and impact toughness in the coarse grain heat-affected zone (CGHAZ) of HQ130 high strength steel were studied by using the weld thermo-simulation test. Fracture morphology and fine structure in the CGHAZ were analyzed by means of SEM, TEM and electron diffraction. Experimental results indicated that the impact toughness and hardness in the CGHAZ (T-m = 1350 degrees C) decreased with increasing cooling time (t(8/5)), and fracture morphology changed from dimple fracture into cleavage fracture. The reason for the toughness decrease is the formation of upper bainite. During application, the welding heat input should be strictly limited, to reduce brittleness in the CGHAZ of HQ130 steel.
文摘Microstructure, precipitates and fracture morphology in the weld metal and he heat-affected zone (HAZ) of Cr18Mo2 ferritic stainless steel have been studied by means of metalloscope, SEM, TEM and X-ray diffractometer. Experimental results indicate that crystalline grain coarsening in HAZ is one of the reason resulting in the embrittlement fracture in the welding zone of the Ferritic stainless steel. Some precipitates (TiC, TiN and Cr2N) in the steel promote production and development of the brittle cracks. in practical applications, the welding heat input should be as small as possible to prevent embrittlement caused by HAZ grain coarsening.
