The Influence of RE on wear resistance of wear resistant cast iron containing low alloy was studied by means of slide wear and impact wear test. Moreover, its microstructure and characteristics of wearing surface was ...The Influence of RE on wear resistance of wear resistant cast iron containing low alloy was studied by means of slide wear and impact wear test. Moreover, its microstructure and characteristics of wearing surface was analyzed. The experimental results show that RE can improve the wear resistance of wear resistant cast iron containing low alloy, especially for impact wear resistance. The optimum wear resistance of wear resistant cast iron containing low alloy modified by RE of 0.046% can be obtained by normalization at 950 ℃ for 3 h. Moreover, the coordinated effect of rare earths and heat treatment was also revealed in this paper.展开更多
The formation and growth of thermal fatigue crack and the function of RE and heat treatment in wear resistance of cast iron containing low alloy were investigated,and it was analyzed in view of the activation energy f...The formation and growth of thermal fatigue crack and the function of RE and heat treatment in wear resistance of cast iron containing low alloy were investigated,and it was analyzed in view of the activation energy for the crack′s propagation. The results show that the thermal fatigue cracks are mainly generated at eutectic carbides,and the cracks are grown by themselves spreading and joining each other. RE can improve the eutectic carbide′s morphology,inhibit the generation and propagation of thermal fatigue cracks,therefore,promote the activation energy for the crack′s propagation,and especially,which is more noticeable in case of the RE modification in combination with heat treatment.展开更多
The effect of cooling rate after 40% hot deformation on structure and mechanical properties of low alloy wear resistance cast iron was investigated by metallographic, scanning electron microscopes and detection of pro...The effect of cooling rate after 40% hot deformation on structure and mechanical properties of low alloy wear resistance cast iron was investigated by metallographic, scanning electron microscopes and detection of properties. The results show that for the cast steel after deformed, the amount of granular carbides of precipitation during the cooling decreased with the increase of the cooling rate, but the hardness was obviously enhanced, as a result, better mechanical properties will be obtained by force air cooling(cooling rate is about 7 ℃·s-1). And the reason of the change for structure and mechanical properties of the cast steel were analyzed.展开更多
The granular carbides formed from hot deformation in multiple alloying wear resistant cast iron were studied through the observation by means of optical microscope, SEM and TEM. The experimental results show that carb...The granular carbides formed from hot deformation in multiple alloying wear resistant cast iron were studied through the observation by means of optical microscope, SEM and TEM. The experimental results show that carbides with large size are formed from original short rhabdoid carbides existing in cast, those with small size directly nucleate in the matrix. Carbides with the size between the above are formed from precipitation induced by hot deformation. The bigger the deformation is, the larger the number of microsized granular carbides is. The mechanisms of nucleation and growth of granular carbides and the function of RE were discussed.展开更多
The influence of heating temperature on mechanical properties of low chromium wear resistant cast iron containing rare earth elements was studied by means of metallographic examination, scanning electron microscopic e...The influence of heating temperature on mechanical properties of low chromium wear resistant cast iron containing rare earth elements was studied by means of metallographic examination, scanning electron microscopic examination and mechanical property test. The experimental results show that heating temperature has great effect on impact toughness (α_k), bending fatigue (σ_(bb)) and relative toughness (σ_(bb)×f), but little effect on hardness (HRC). When the specimen was held at 960 ℃ for 3 h, it has better comprehensive mechanical properties, and the reason and regularity of the change for mechanical properties of the cast iron were reviewed.展开更多
The low-energy, multi-impact fracture resistance and the abrasiveness of the cross-rolled low alloy white cast iron grinding balls were studied after heat treatments at residual rolling temperature. Moreover, the mean...The low-energy, multi-impact fracture resistance and the abrasiveness of the cross-rolled low alloy white cast iron grinding balls were studied after heat treatments at residual rolling temperature. Moreover, the means by which they are damaged and characters of the wear surface were analyzed. The results show that high resistance to impact fracture and high abrasiveness can be achieved after appropriate heat treatment at residual rolling temperature. This kind of heat treatment technology has several advantages under low impact and hard abrasive. These results are very useful for determining the optimized heat treatment technology at residual rolling temperatures.展开更多
The effect of cooling rate on structure and properties of wear-resistant low chromium cast iron after 40% hot deformation was investigated by metallographic and scanning electron microscope. The results show that the ...The effect of cooling rate on structure and properties of wear-resistant low chromium cast iron after 40% hot deformation was investigated by metallographic and scanning electron microscope. The results show that the cooling rate is closely related to the structure and properties, and for the cast iron, the best comprehensive mechanical properties were obtained by forced air cooling with a cooling rate as about 7 ℃/s. The reason and regularity for the change of mechanical properties were analyzed.展开更多
Rolling process based on the plastic deformation as a surface strengthening treatment was employed,aiming to improve the wear resistance ability and functional performance of the high carbon equivalent gray cast iron(...Rolling process based on the plastic deformation as a surface strengthening treatment was employed,aiming to improve the wear resistance ability and functional performance of the high carbon equivalent gray cast iron(HCEGCI).The microstructures and tribological performance of the untreated and rolled samples were characterized.In addition,the wear mechanism of HCEGCI samples was also studied via pin-on-disc tests.The experimental results show that the as-rolled samples possess the structure-refined layer of 15μm and work-hardened layer of 0.13 mm.In comparison with the surface hardness of untreated samples,the surface hardness of as-rolled samples increases by 84.6%(from 240HV0.1 to 443HV0.1)and the residual compressive stresses existed within the range of 0.2 mm.The wear rates of as-rolled samples were decreased by 38.4%,37.5%,and 44.4%under different loads of 5 N,10 N,and 15 N,respectively.The wear characteristics of the untreated samples mainly exhibit the peeling wear coupled with partial adhesive and abrasive wear.However,as for the as-rolled samples,the adhesive wear was limited by the structure-refined layer and the micro-crack propagation was controlled by the work-hardened layer.Therefore,the wear resistance of as-rolled samples can be improved significantly due to the low wearing degree of the friction contact zone.展开更多
Metal casting is an important manufacturing technology for efficiently producing massive components with complex shape.A large share of industrial castings is made from iron and steel alloys,combining attractive prope...Metal casting is an important manufacturing technology for efficiently producing massive components with complex shape.A large share of industrial castings is made from iron and steel alloys,combining attractive properties and low production cost.Upgrading of properties in cast iron and steel is mainly achieved by alloying and in fewer cases by heat treatment.Molybdenum is an important alloying element in that respect,increasing strength,hardness and toughness.It also facilitates particular heat treatments such as austempering.The paper describes the metallurgical functionality of molybdenum alloying in iron-based castings and demonstrates its effectiveness for applications in the automotive and mining industry.展开更多
文摘The Influence of RE on wear resistance of wear resistant cast iron containing low alloy was studied by means of slide wear and impact wear test. Moreover, its microstructure and characteristics of wearing surface was analyzed. The experimental results show that RE can improve the wear resistance of wear resistant cast iron containing low alloy, especially for impact wear resistance. The optimum wear resistance of wear resistant cast iron containing low alloy modified by RE of 0.046% can be obtained by normalization at 950 ℃ for 3 h. Moreover, the coordinated effect of rare earths and heat treatment was also revealed in this paper.
文摘The formation and growth of thermal fatigue crack and the function of RE and heat treatment in wear resistance of cast iron containing low alloy were investigated,and it was analyzed in view of the activation energy for the crack′s propagation. The results show that the thermal fatigue cracks are mainly generated at eutectic carbides,and the cracks are grown by themselves spreading and joining each other. RE can improve the eutectic carbide′s morphology,inhibit the generation and propagation of thermal fatigue cracks,therefore,promote the activation energy for the crack′s propagation,and especially,which is more noticeable in case of the RE modification in combination with heat treatment.
文摘The effect of cooling rate after 40% hot deformation on structure and mechanical properties of low alloy wear resistance cast iron was investigated by metallographic, scanning electron microscopes and detection of properties. The results show that for the cast steel after deformed, the amount of granular carbides of precipitation during the cooling decreased with the increase of the cooling rate, but the hardness was obviously enhanced, as a result, better mechanical properties will be obtained by force air cooling(cooling rate is about 7 ℃·s-1). And the reason of the change for structure and mechanical properties of the cast steel were analyzed.
文摘The granular carbides formed from hot deformation in multiple alloying wear resistant cast iron were studied through the observation by means of optical microscope, SEM and TEM. The experimental results show that carbides with large size are formed from original short rhabdoid carbides existing in cast, those with small size directly nucleate in the matrix. Carbides with the size between the above are formed from precipitation induced by hot deformation. The bigger the deformation is, the larger the number of microsized granular carbides is. The mechanisms of nucleation and growth of granular carbides and the function of RE were discussed.
文摘The influence of heating temperature on mechanical properties of low chromium wear resistant cast iron containing rare earth elements was studied by means of metallographic examination, scanning electron microscopic examination and mechanical property test. The experimental results show that heating temperature has great effect on impact toughness (α_k), bending fatigue (σ_(bb)) and relative toughness (σ_(bb)×f), but little effect on hardness (HRC). When the specimen was held at 960 ℃ for 3 h, it has better comprehensive mechanical properties, and the reason and regularity of the change for mechanical properties of the cast iron were reviewed.
基金Item Sponsored by Guiding Program of Science and Technology Research of Jilin Province of China (20000513)
文摘The low-energy, multi-impact fracture resistance and the abrasiveness of the cross-rolled low alloy white cast iron grinding balls were studied after heat treatments at residual rolling temperature. Moreover, the means by which they are damaged and characters of the wear surface were analyzed. The results show that high resistance to impact fracture and high abrasiveness can be achieved after appropriate heat treatment at residual rolling temperature. This kind of heat treatment technology has several advantages under low impact and hard abrasive. These results are very useful for determining the optimized heat treatment technology at residual rolling temperatures.
文摘The effect of cooling rate on structure and properties of wear-resistant low chromium cast iron after 40% hot deformation was investigated by metallographic and scanning electron microscope. The results show that the cooling rate is closely related to the structure and properties, and for the cast iron, the best comprehensive mechanical properties were obtained by forced air cooling with a cooling rate as about 7 ℃/s. The reason and regularity for the change of mechanical properties were analyzed.
基金Funded by the National Natural Science Foundation of China(No.51872254)the Yangzhou Hanjiang District Science and Technology Plan Project of China(No.HJM2019006)。
文摘Rolling process based on the plastic deformation as a surface strengthening treatment was employed,aiming to improve the wear resistance ability and functional performance of the high carbon equivalent gray cast iron(HCEGCI).The microstructures and tribological performance of the untreated and rolled samples were characterized.In addition,the wear mechanism of HCEGCI samples was also studied via pin-on-disc tests.The experimental results show that the as-rolled samples possess the structure-refined layer of 15μm and work-hardened layer of 0.13 mm.In comparison with the surface hardness of untreated samples,the surface hardness of as-rolled samples increases by 84.6%(from 240HV0.1 to 443HV0.1)and the residual compressive stresses existed within the range of 0.2 mm.The wear rates of as-rolled samples were decreased by 38.4%,37.5%,and 44.4%under different loads of 5 N,10 N,and 15 N,respectively.The wear characteristics of the untreated samples mainly exhibit the peeling wear coupled with partial adhesive and abrasive wear.However,as for the as-rolled samples,the adhesive wear was limited by the structure-refined layer and the micro-crack propagation was controlled by the work-hardened layer.Therefore,the wear resistance of as-rolled samples can be improved significantly due to the low wearing degree of the friction contact zone.
文摘Metal casting is an important manufacturing technology for efficiently producing massive components with complex shape.A large share of industrial castings is made from iron and steel alloys,combining attractive properties and low production cost.Upgrading of properties in cast iron and steel is mainly achieved by alloying and in fewer cases by heat treatment.Molybdenum is an important alloying element in that respect,increasing strength,hardness and toughness.It also facilitates particular heat treatments such as austempering.The paper describes the metallurgical functionality of molybdenum alloying in iron-based castings and demonstrates its effectiveness for applications in the automotive and mining industry.
