Effects of quenching temperature and cooling conditions(water cooling and 10%NaCl cooling)on microstructure and mechanical properties of a 0.2%Ti low alloy martensitic wear-resistant steel used for die casting ejector...Effects of quenching temperature and cooling conditions(water cooling and 10%NaCl cooling)on microstructure and mechanical properties of a 0.2%Ti low alloy martensitic wear-resistant steel used for die casting ejector plate were investigated.The results show that lath martensite can be obtained after austenitizing in the range of 860-980℃and then water cooling.With an increase in austenitizing temperature,the precipitate content gradually decreases.The precipitates are mainly composed of TiC and Ti4C2S2,and their total content is between 1.15wt.%and 1.64wt.%.The precipitate phase concentration by water-cooling is higher than that by10%NaCl cooling due to the lower cooling rate of water cooling.As the austeniting temperature increases,the hardness and tensile strength of both water cooled and 10%NaCl cooled steels firstly increase and then decrease.The experimental steel exhibits the best comprehensive mechanical properties after being austenitized at 900℃,cooled by 10%NaCl,and then tempered at 200℃.Its hardness,ultimate tensile strength,and wear rate reach551.4 HBW,1,438.2 MPa,and 0.48×10^(-2)mg·m^(-1),respectively.展开更多
TiC_p/ZA-12 composites were fabricated by exothermic disposition method process and stirring-casting techniques. The microstructure and wear-resistant properties were investigated . The results show that TiC particles...TiC_p/ZA-12 composites were fabricated by exothermic disposition method process and stirring-casting techniques. The microstructure and wear-resistant properties were investigated . The results show that TiC particles are formed in-situ and distributed uniformly in matrix. No particles aggregation and macro or micro precipitation are observed. The wear-resistant properties of composites increase with the increase of TiC_p content, but will not increase when the TiC_p content reaches constant value. Finally, the friction and wear mechanism were also discussed.展开更多
With its high strength and hardness, wear-resistant steel has become an important material in the field of construction machinery manufacturing.Given that quenching technology is a crucial component of wear-resistant ...With its high strength and hardness, wear-resistant steel has become an important material in the field of construction machinery manufacturing.Given that quenching technology is a crucial component of wear-resistant steel production, the selection of the cooling method to be used during this process is important.In this study, the feasibility of quenching wear-resistant steel by air-atomized water spray cooling was studied, and the cooling rate, microstructure, and hardness of wear-resistant steel under various cooling device structures were analyzed.The results reveal that the air-atomized water spray cooling method is an effective technique in quenching wear-resistant steel.Furthermore, martensite and uniform hardness were obtained by the air-atomized water spray cooling technique.As the space between the nozzles in each row in the device increased, the cooling rate was reduced during quenching.Meanwhile, the martensite content decreased, and more carbides were observed in the martensitic structure.A mixture comprising self-tempered martensite and bainite was formed at a large distance over a longer period of time.All these factors resulted in lower hardness and worse property uniformity.展开更多
Using ABAQUS software and cylindrical ellipsoid and body heat sources with a peak-heat-flux- attenuation function, a finite element model of the temperature field in the laser-arc hybrid welding of 4.5-mm BW300TP wear...Using ABAQUS software and cylindrical ellipsoid and body heat sources with a peak-heat-flux- attenuation function, a finite element model of the temperature field in the laser-arc hybrid welding of 4.5-mm BW300TP wear-resistant steel is proposed. The proposed model considers convection, radiation, molten pool flow, and heat conduction effect on temperature. A comparison of the simulation and actual welding test results confirms the reliability of the model. This welding heat-process model can provide the cooling rate at any position in the heat affected zone （HAZ） and can be used as a reference for the analysis of material properties and for process optimization.展开更多
Baosteel’s first BTW1 austenitic high-manganese wear-resistant steel exhibits strong deformation-induced hardening characteristics.Compared with common low-alloy martensitic wear-resistant steels in the market, it ha...Baosteel’s first BTW1 austenitic high-manganese wear-resistant steel exhibits strong deformation-induced hardening characteristics.Compared with common low-alloy martensitic wear-resistant steels in the market, it has improved impact wear resistance, hard abrasive wear, erosion wear performance, and impact toughness.The metallurgical properties of such austenitic wear-resistant steel lead to the risk of failure because of hot cracking defects in the welded structure.In wear-resistant applications, evaluating hot cracking susceptibility is necessary to avoid the effect of welding defects.In this study, the Varestraint test is used to quantitatively analyze and evaluate the hot cracking susceptibility of BTW1 austenitic high-manganese wear-resistant steel.The test results show that by controlling the content of impurity elements and grain refinement, BTW1 austenitic high-manganese wear-resistant steel effectively reduces hot cracking tendency and has a low incidence of hot cracking under small strain conditions.The developed matching welding process can effectively avoid the influence of hot cracking susceptibility.展开更多
Maanshan KuangyouGroup company is a special largeenterprise making wear-resistantmaterials products,integratingscience,industry and trade.Mainproducts are chromium-contentwear-resistant materials and ship-use anchor c...Maanshan KuangyouGroup company is a special largeenterprise making wear-resistantmaterials products,integratingscience,industry and trade.Mainproducts are chromium-contentwear-resistant materials and ship-use anchor chains."Kuangyou"Brand balls have been awardedprizes of Quality Products by theprovince and ministry,and prizeof Scientific Progress by theprovince,and are widely appliedin mining,cement,power andchemicals industries.Ship-useanchor chains have an展开更多
A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring o...A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring oxide film in order to improve its tribological properties. Improvement is needed at low temperatures where the oxide film, previously formed at high temperature, spalls due to stresses induced by sliding. Experiments with Ti, W and Ta additions show a beneficial effect when added to Ni and Ni-base alloys. Low friction can be maintained down to 100℃ from 900℃. For unalloyed Ni friction and surface damage increases at 400℃ to 500℃. Two new alloys were perpared based on the beneficial results of binary alloys and ZrO2 diffusion in Ni.Low friction at temperature above 500℃ and reasonable values (0.32~0.42) at low temperature are obtained.展开更多
Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 h...Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.展开更多
The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces wer...The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear-resistance.展开更多
Alloy powders including Ni60, WC, CrC, and TiC with different mass ratios were deposited on medium carbon low alloy steel by plasma welding. Through the experiments, the optimal alloy powder reinforcing cutter tool su...Alloy powders including Ni60, WC, CrC, and TiC with different mass ratios were deposited on medium carbon low alloy steel by plasma welding. Through the experiments, the optimal alloy powder reinforcing cutter tool surface properties were discovered. The wear resistance properties were investigated on the impact abrasive wear tester. The experimental results show that in terms of microstructure, there exists the shape of herringbone, spider mesh, broken flower structures in coatings. In addition, fusion area of four specimens surfacing welding layer displays a large number of acicular martensite with a small amount of austenite. The coating mainly consists of Ni-Cr-Fe austenitic phase and the other precipitates. TiC density is smaller, its content is less in alloy powder, in the process of surfacing welding, TiC is melted fully, which is mainly distributed in surface layer and middle layer of hard facing layer. The content of TiC gradually reduces from surface layer of hard facing layer to the fusion area. Compared to TiC, the density of tungsten carbide and chromium carbide is larger, there exist tungsten carbide and chromium carbide particles, which are not completely melted near the fusion area. The micro-hardness presents gradient change from the fusion area to the surface layer of hard facing layer, and the hardness of the middle layer is slightly lower than that of the fusion area, and the hardness increases near the surface layer.展开更多
The process of wear process expedient considering as set of special cases wear. For each special case wear were received settlement with reference to some certain conditions of experimental researches realisation, uni...The process of wear process expedient considering as set of special cases wear. For each special case wear were received settlement with reference to some certain conditions of experimental researches realisation, uniting in self SLOP. For successful application deduced dependence at forecasting wear-resistance the mechanism of reduction is developed which allows to distribute deduced dependencies to any conditions of wear process.展开更多
文摘Effects of quenching temperature and cooling conditions(water cooling and 10%NaCl cooling)on microstructure and mechanical properties of a 0.2%Ti low alloy martensitic wear-resistant steel used for die casting ejector plate were investigated.The results show that lath martensite can be obtained after austenitizing in the range of 860-980℃and then water cooling.With an increase in austenitizing temperature,the precipitate content gradually decreases.The precipitates are mainly composed of TiC and Ti4C2S2,and their total content is between 1.15wt.%and 1.64wt.%.The precipitate phase concentration by water-cooling is higher than that by10%NaCl cooling due to the lower cooling rate of water cooling.As the austeniting temperature increases,the hardness and tensile strength of both water cooled and 10%NaCl cooled steels firstly increase and then decrease.The experimental steel exhibits the best comprehensive mechanical properties after being austenitized at 900℃,cooled by 10%NaCl,and then tempered at 200℃.Its hardness,ultimate tensile strength,and wear rate reach551.4 HBW,1,438.2 MPa,and 0.48×10^(-2)mg·m^(-1),respectively.
文摘TiC_p/ZA-12 composites were fabricated by exothermic disposition method process and stirring-casting techniques. The microstructure and wear-resistant properties were investigated . The results show that TiC particles are formed in-situ and distributed uniformly in matrix. No particles aggregation and macro or micro precipitation are observed. The wear-resistant properties of composites increase with the increase of TiC_p content, but will not increase when the TiC_p content reaches constant value. Finally, the friction and wear mechanism were also discussed.
文摘With its high strength and hardness, wear-resistant steel has become an important material in the field of construction machinery manufacturing.Given that quenching technology is a crucial component of wear-resistant steel production, the selection of the cooling method to be used during this process is important.In this study, the feasibility of quenching wear-resistant steel by air-atomized water spray cooling was studied, and the cooling rate, microstructure, and hardness of wear-resistant steel under various cooling device structures were analyzed.The results reveal that the air-atomized water spray cooling method is an effective technique in quenching wear-resistant steel.Furthermore, martensite and uniform hardness were obtained by the air-atomized water spray cooling technique.As the space between the nozzles in each row in the device increased, the cooling rate was reduced during quenching.Meanwhile, the martensite content decreased, and more carbides were observed in the martensitic structure.A mixture comprising self-tempered martensite and bainite was formed at a large distance over a longer period of time.All these factors resulted in lower hardness and worse property uniformity.
文摘Using ABAQUS software and cylindrical ellipsoid and body heat sources with a peak-heat-flux- attenuation function, a finite element model of the temperature field in the laser-arc hybrid welding of 4.5-mm BW300TP wear-resistant steel is proposed. The proposed model considers convection, radiation, molten pool flow, and heat conduction effect on temperature. A comparison of the simulation and actual welding test results confirms the reliability of the model. This welding heat-process model can provide the cooling rate at any position in the heat affected zone （HAZ） and can be used as a reference for the analysis of material properties and for process optimization.
文摘Baosteel’s first BTW1 austenitic high-manganese wear-resistant steel exhibits strong deformation-induced hardening characteristics.Compared with common low-alloy martensitic wear-resistant steels in the market, it has improved impact wear resistance, hard abrasive wear, erosion wear performance, and impact toughness.The metallurgical properties of such austenitic wear-resistant steel lead to the risk of failure because of hot cracking defects in the welded structure.In wear-resistant applications, evaluating hot cracking susceptibility is necessary to avoid the effect of welding defects.In this study, the Varestraint test is used to quantitatively analyze and evaluate the hot cracking susceptibility of BTW1 austenitic high-manganese wear-resistant steel.The test results show that by controlling the content of impurity elements and grain refinement, BTW1 austenitic high-manganese wear-resistant steel effectively reduces hot cracking tendency and has a low incidence of hot cracking under small strain conditions.The developed matching welding process can effectively avoid the influence of hot cracking susceptibility.
文摘Maanshan KuangyouGroup company is a special largeenterprise making wear-resistantmaterials products,integratingscience,industry and trade.Mainproducts are chromium-contentwear-resistant materials and ship-use anchor chains."Kuangyou"Brand balls have been awardedprizes of Quality Products by theprovince and ministry,and prizeof Scientific Progress by theprovince,and are widely appliedin mining,cement,power andchemicals industries.Ship-useanchor chains have an
文摘A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring oxide film in order to improve its tribological properties. Improvement is needed at low temperatures where the oxide film, previously formed at high temperature, spalls due to stresses induced by sliding. Experiments with Ti, W and Ta additions show a beneficial effect when added to Ni and Ni-base alloys. Low friction can be maintained down to 100℃ from 900℃. For unalloyed Ni friction and surface damage increases at 400℃ to 500℃. Two new alloys were perpared based on the beneficial results of binary alloys and ZrO2 diffusion in Ni.Low friction at temperature above 500℃ and reasonable values (0.32~0.42) at low temperature are obtained.
基金This work was financially supported by National Nature Science Foundation of China (No.50075026)and Education Ministry of China (No.[2000]65)and research funding from Guangdong Provincial High Education Department (Thousand, Hundred Ten Project).]
文摘Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.
文摘The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear-resistance.
基金Funded by the National Science and Technology Support Project(2006BAK02B01-02)
文摘Alloy powders including Ni60, WC, CrC, and TiC with different mass ratios were deposited on medium carbon low alloy steel by plasma welding. Through the experiments, the optimal alloy powder reinforcing cutter tool surface properties were discovered. The wear resistance properties were investigated on the impact abrasive wear tester. The experimental results show that in terms of microstructure, there exists the shape of herringbone, spider mesh, broken flower structures in coatings. In addition, fusion area of four specimens surfacing welding layer displays a large number of acicular martensite with a small amount of austenite. The coating mainly consists of Ni-Cr-Fe austenitic phase and the other precipitates. TiC density is smaller, its content is less in alloy powder, in the process of surfacing welding, TiC is melted fully, which is mainly distributed in surface layer and middle layer of hard facing layer. The content of TiC gradually reduces from surface layer of hard facing layer to the fusion area. Compared to TiC, the density of tungsten carbide and chromium carbide is larger, there exist tungsten carbide and chromium carbide particles, which are not completely melted near the fusion area. The micro-hardness presents gradient change from the fusion area to the surface layer of hard facing layer, and the hardness of the middle layer is slightly lower than that of the fusion area, and the hardness increases near the surface layer.
文摘The process of wear process expedient considering as set of special cases wear. For each special case wear were received settlement with reference to some certain conditions of experimental researches realisation, uniting in self SLOP. For successful application deduced dependence at forecasting wear-resistance the mechanism of reduction is developed which allows to distribute deduced dependencies to any conditions of wear process.
