The coating material of a tool directly affects the efficiency and cost of machining malleable cast iron.However,the machining adaptability of various coating materials to malleable cast iron has been insufficiently r...The coating material of a tool directly affects the efficiency and cost of machining malleable cast iron.However,the machining adaptability of various coating materials to malleable cast iron has been insufficiently researched.In this paper,turning tests were conducted on cemented carbide tools with different coatings(a thick TiN/TiAlN coating,a thin TiN/TiAlN coating,and a nanocomposite(nc)TiAlSiN coating).All coatings were applied by physical vapor deposition.In a comparative study of chip morphology,cutting force,cutting temperature,specific cutting energy,tool wear,and surface roughness,this study analyzed the cutting characteristics of the tools coated with various materials,and established the relationship between the cutting parameters and machining objectives.The results showed that in malleable cast iron machining,the coating material significantly affects the cutting performance of the tool.Among the three tools,the nc-TiAlSiN-coated carbide tool achieved the minimum cutting force,the lowest cutting temperature,least tool wear,longest tool life,and best surface quality.Moreover,in comparisons between cemented-carbide and compacted-graphite cast iron machined under the same conditions,the wear mechanism of the coated tools was found to depend on the cast iron being machined.Therefore,the performance requirements of a tool depend on multiple factors,and selecting an appropriately coated tool for a particular cast iron material is essential.展开更多
The structure of white iron treated with Si-Bi-AI complex inoculant has been observed by SEM and TEM. The results show that, in comparison with the samples treated with ordinary inoculants, disorder, overlapping and i...The structure of white iron treated with Si-Bi-AI complex inoculant has been observed by SEM and TEM. The results show that, in comparison with the samples treated with ordinary inoculants, disorder, overlapping and inflexion of the pearlitic lamella appear, besides, the dis- location density increases apparently. The graphitization can be quickly realized at the tem- perature lower than that of austenitic transition (720℃).展开更多
The filling and solidification of a malleable iron pipe casting manufactured by DISA casting mold line with different design parameters were calculated by using software MAGMASOFT. Then the shrinkage porosity was pred...The filling and solidification of a malleable iron pipe casting manufactured by DISA casting mold line with different design parameters were calculated by using software MAGMASOFT. Then the shrinkage porosity was predicted by thermal criterion. Based on the simulation results, the influences of the runner ratio and feeder position on the porosity were discussed. The results show that synchronization of injection can be significantly influenced by the size of downsprue section, and an de-sign structure of DISA gating system was used to solve the problem of flow imbalance in the filling procegs. At the same time, the riser was designed on the hotspot for feeding shrinkage. At last, the optimizated gating system and feeding system were ac-complished to eliminate shrinkage porosity.展开更多
基金Supported by National Major Science and Technology Projects of China(Grant No.SK201901A31-04)Key Program of NSFC-Guangdong Joint Fund,China(Grant No.U1201245).
文摘The coating material of a tool directly affects the efficiency and cost of machining malleable cast iron.However,the machining adaptability of various coating materials to malleable cast iron has been insufficiently researched.In this paper,turning tests were conducted on cemented carbide tools with different coatings(a thick TiN/TiAlN coating,a thin TiN/TiAlN coating,and a nanocomposite(nc)TiAlSiN coating).All coatings were applied by physical vapor deposition.In a comparative study of chip morphology,cutting force,cutting temperature,specific cutting energy,tool wear,and surface roughness,this study analyzed the cutting characteristics of the tools coated with various materials,and established the relationship between the cutting parameters and machining objectives.The results showed that in malleable cast iron machining,the coating material significantly affects the cutting performance of the tool.Among the three tools,the nc-TiAlSiN-coated carbide tool achieved the minimum cutting force,the lowest cutting temperature,least tool wear,longest tool life,and best surface quality.Moreover,in comparisons between cemented-carbide and compacted-graphite cast iron machined under the same conditions,the wear mechanism of the coated tools was found to depend on the cast iron being machined.Therefore,the performance requirements of a tool depend on multiple factors,and selecting an appropriately coated tool for a particular cast iron material is essential.
文摘The structure of white iron treated with Si-Bi-AI complex inoculant has been observed by SEM and TEM. The results show that, in comparison with the samples treated with ordinary inoculants, disorder, overlapping and inflexion of the pearlitic lamella appear, besides, the dis- location density increases apparently. The graphitization can be quickly realized at the tem- perature lower than that of austenitic transition (720℃).
文摘The filling and solidification of a malleable iron pipe casting manufactured by DISA casting mold line with different design parameters were calculated by using software MAGMASOFT. Then the shrinkage porosity was predicted by thermal criterion. Based on the simulation results, the influences of the runner ratio and feeder position on the porosity were discussed. The results show that synchronization of injection can be significantly influenced by the size of downsprue section, and an de-sign structure of DISA gating system was used to solve the problem of flow imbalance in the filling procegs. At the same time, the riser was designed on the hotspot for feeding shrinkage. At last, the optimizated gating system and feeding system were ac-complished to eliminate shrinkage porosity.
