Influence Of Methods Of Sintering And The Heat Treatment On The Microstructure And Properties Of Steel Bonded Titanium Carbide

Using high manganese steel as the hammer head material and casting themanganese steel bonded titanium carbide in the “strike face” of the hammer has beenan important way to produce hammer, and because of its good resistance property, thiskind of hammer has been more and more used in the cement industry. The practical useshows that the quality and the performance of the manganese steel bonded titaniumcarbide seriously affect the service life of the hammer. Using the traditional sinteringmethod to produce the wear resistant block has its drawbacks such as high brittleness,fracture phenomenon and falling off from the manganese. In this paper, firstly differentproducing methods were discussed on the microstructure and mechanical properties ofthe wear resistant block. Secondly the effects of water toughening on themicrostructure and mechanical properties of the high manganese steel bonded titaniumcarbide were studied. At last the fracture behavior and mechanism were analyzed to geta solid theory foundation in producing the manganese steel bonded titanium carbide.Vacuum sintering, low pressure sintering and hot isostatic pressing were used toproduce the samples, and then we explored the inner connection of the producingmethods, microstructure and mechanical properties. The results show that comparingwith vacuum sintering, the low pressure sintering and hot isostatic pressing reduce theporosity and improve the mechanical properties of the samples. The low pressuresintering has many advantages such as low costs, a low sintering temperature, a shorttime and a better microstructure. In this study, the low pressure sintering:1410℃×50min, the sintering atmosphere pressure:5.0MPa; The bending strength and impacttoughness of the steel bonded TiC are2325MPa and1.3J/cm~2.In this paper,1050℃and1080℃were evaluated on the effects of the samples byvacuum sintering. The results show that the holding time at high temperature promotesthe element diffusion at interface to improve the mechanical properties of the alloy.There is a right temperature in the water toughening.1050℃is recommended. Afterthe water toughening the bending and impact toughness of the steel bonded TiC are3373MPa and1.3J/cm~2.The recommended water toughening treatment process was used for the steelbonded TiC by the low pressure sintering and hot isostatic pressing. We found thatphase interface bonding strength was improved. So the steel bonded carbide whichdoesn’t need the heat treatment should be heated in1050℃for some time to improve its mechanical properties.There are three fracture patterns of the steel bonded carbide which are the hardphrase being uprooted, the crack propagation and the hard phrase rupture. The fracturemechanism depends on the microstructure, the interface combination and the stress.The river shape pattern is easy to be shaped in the hard phrase with large particle size.The fracture pattern of the hard phrase with small particle size is intergranular fractureand the dimple fracture appears. The water toughening treatment reduces the interfacedebonding phenomenon. The residual porosity, the inclusion, the hard phase with largeparticle size and the hard phase zones are the main crack source. To improve themixing uniformity in the process of ball mill and preventing the particles fromagglomeration can get a good microstructure and improve the crack resistancecapacity.