The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this...The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this evaluation is difficult since it relies on an in-depth understanding of the operating mechanism of SCCSs, and few existing methods can be used to conduct the evaluation, due to the lack of full-scale consideration of the multiple factors related to the production operation. In this study, three quantitative models were developed, and the multiprocess collaborative operation level was evaluated through the laminar-flow operation degree, the process matching degree, and the scheduling strategy availability degree. Based on the evaluation models for the laminar-flow operation and process matching levels, this study investigated the production status of two steelmaking plants, plants A and B, based on actual production data. The average laminar-flow operation(process matching) degrees of SCCSs were obtained as 0.638(0.610) and 1.000(0.759) for plants A and B, respectively, for the period of April to July 2019. Then, a scheduling strategy based on the optimization of the furnace-caster coordinating mode was suggested for plant A. Simulation experiments showed higher availability than the greedy-based and manual strategies. After the proposed scheduling strategy was applied,the average process matching degree of the SCCS of plant A increased by 4.6% for the period of September to November 2019. The multi-process collaborative operation level was improved with fewer adjustments and interruptions in casting.展开更多
Turbine blade is one of the critical components of aircraft engine.The performance of the engine depends on the shape and dimensions of components,but superalloy blade material cannot be easily machined.Although inves...Turbine blade is one of the critical components of aircraft engine.The performance of the engine depends on the shape and dimensions of components,but superalloy blade material cannot be easily machined.Although investment casting is an ideal process for such net-shape components,it requires an accurate determination of the casting-die profile.In this paper,a reversing design methodology for investment casting die using ProCAST is proposed.By combining the methods of simplifying grid files and quick sorting,the efficiency of sorting and matching can be largely improved.Further,the mould/die cavity anti-deformation system can be easily built.With ProCAST,the optimized die profile for investment casting can be established.展开更多
The dispersion, stabilization and rheological properties of the slurry with various relative molecular masses of PVB were studied. The sintering properties, microstructure and dielectric properties of borosilicate gla...The dispersion, stabilization and rheological properties of the slurry with various relative molecular masses of PVB were studied. The sintering properties, microstructure and dielectric properties of borosilicate glass/Al2O3 composites were also investigated. The intensities of the typical vibrating bands decrease with the decrease of the relative molecular mass of PVB, which demonstrates that the content of butyral groups in PVB binders decreases correspondingly, leading to a rapid decrease in the viscosity of the mixed slurry. The solid content of samples increases with the decrease of the relative molecular mass of PVB, and this further leads to the increase of tape thickness, bulk density and dried-shrinkage coefficient of tapes. The bulk density, relative density, three-point strength and dielectric constant of sintered samples increase with the increase of the solid content, and the shrinkage and dielectric loss decrease. By contrast, samples for PVB-5s exhibit better properties of a bulk density of 3.10g/cm3 , a relative density of 98.1%, a three-point strength of 208 MPa, a ε r value of 8.01, a tanδ value of 7.6×10-4 at 10 MHz and a well matching with Ag electrodes.展开更多
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
基金financially supported by the National Natural Science Foundation of China (Nos.50874014 and 51974023)the Fundamental Research Funds for Central Universities (No.FRF-BR-17-029A)。
文摘The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this evaluation is difficult since it relies on an in-depth understanding of the operating mechanism of SCCSs, and few existing methods can be used to conduct the evaluation, due to the lack of full-scale consideration of the multiple factors related to the production operation. In this study, three quantitative models were developed, and the multiprocess collaborative operation level was evaluated through the laminar-flow operation degree, the process matching degree, and the scheduling strategy availability degree. Based on the evaluation models for the laminar-flow operation and process matching levels, this study investigated the production status of two steelmaking plants, plants A and B, based on actual production data. The average laminar-flow operation(process matching) degrees of SCCSs were obtained as 0.638(0.610) and 1.000(0.759) for plants A and B, respectively, for the period of April to July 2019. Then, a scheduling strategy based on the optimization of the furnace-caster coordinating mode was suggested for plant A. Simulation experiments showed higher availability than the greedy-based and manual strategies. After the proposed scheduling strategy was applied,the average process matching degree of the SCCS of plant A increased by 4.6% for the period of September to November 2019. The multi-process collaborative operation level was improved with fewer adjustments and interruptions in casting.
基金supported by National Key Technologies R&D Program under Grant No. 2006BAF04B02
文摘Turbine blade is one of the critical components of aircraft engine.The performance of the engine depends on the shape and dimensions of components,but superalloy blade material cannot be easily machined.Although investment casting is an ideal process for such net-shape components,it requires an accurate determination of the casting-die profile.In this paper,a reversing design methodology for investment casting die using ProCAST is proposed.By combining the methods of simplifying grid files and quick sorting,the efficiency of sorting and matching can be largely improved.Further,the mould/die cavity anti-deformation system can be easily built.With ProCAST,the optimized die profile for investment casting can be established.
基金Project(2007AA03Z455) supported by the National High Technology Research and Development Program of ChinaProjects(BE2009168)supported by Science&Technology Pillar Program of Jiangsu Province, China+2 种基金Project supported by the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions, ChinaProject(CXZZ12_0415) supported by the Innovation Foundation for Graduate Students of Jiangsu Province, ChinaProject(IRT1146) supported for Changjiang Scholars and Innovative Research Teamin University (PCSIRT) of China
文摘The dispersion, stabilization and rheological properties of the slurry with various relative molecular masses of PVB were studied. The sintering properties, microstructure and dielectric properties of borosilicate glass/Al2O3 composites were also investigated. The intensities of the typical vibrating bands decrease with the decrease of the relative molecular mass of PVB, which demonstrates that the content of butyral groups in PVB binders decreases correspondingly, leading to a rapid decrease in the viscosity of the mixed slurry. The solid content of samples increases with the decrease of the relative molecular mass of PVB, and this further leads to the increase of tape thickness, bulk density and dried-shrinkage coefficient of tapes. The bulk density, relative density, three-point strength and dielectric constant of sintered samples increase with the increase of the solid content, and the shrinkage and dielectric loss decrease. By contrast, samples for PVB-5s exhibit better properties of a bulk density of 3.10g/cm3 , a relative density of 98.1%, a three-point strength of 208 MPa, a ε r value of 8.01, a tanδ value of 7.6×10-4 at 10 MHz and a well matching with Ag electrodes.
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.