In order to improve the bonding strength between piston alloys and cast iron ring of aluminum piston with reinforced cast iron ring,the different methods of the surface treatments(shot blasting and sand blasting) to t...In order to improve the bonding strength between piston alloys and cast iron ring of aluminum piston with reinforced cast iron ring,the different methods of the surface treatments(shot blasting and sand blasting) to the cast iron ring are experimented.The optical micrograph shows that an intermetallic layer and a ligulate shaped structure are formed between piston alloys and cast iron base ring.After sand blasting treatment,the ring surface is non-metal shiny,matte-like and has no obvious pits.The intermetallic layer thickness formed between piston alloys and cast iron is thinner and more equally distributed after sand blasting to the ring.The content of the graphite distributed the interfacial zone after the shot blasting treatment is little.With the increase of time by sand blasting,the hardness starts to slightly descend.The bonding strength of the sample by sand blasting is obviously higher than that by shot blasting and increases from 9.32 MPa to 19.53 MPa.展开更多
The surface of nodular cast iron （NCI） with a ferrite substrate was rapidly remelted and solidified by plasma transferred arc （PTA） to induce a chilled structure with high hardness and favorable wear resistance. T...The surface of nodular cast iron （NCI） with a ferrite substrate was rapidly remelted and solidified by plasma transferred arc （PTA） to induce a chilled structure with high hardness and favorable wear resistance. The effect of scanning speed on the microstructure, micro-hardness distribution, and wear properties of PTA-remelted specimens was systematically investigated. Microstructural characterization in-dicated that the PTA remelting treatment could dissolve most graphite nodules and that the crystallized primary austenite dendrites were transformed into cementite, martensite, an interdendritic network of ledeburite eutectic, and certain residual austenite during rapid solidifica-tion. The dimensions of the remelted zone and its dendrites increase with decreased scanning speed. The microhardness of the remelted zone varied in the range of 650 HV0.2 to 820 HV0.2, which is approximately 2.3-3.1 times higher than the hardness of the substrate. The wear re-sistance of NCI was also significantly improved after the PTA remelting treatment.展开更多
In order to repair and reuse remaining quenching surface(RQS)divided into severely worn surface(SWun-S)and mildly worn surface(MWun-S)of abandoned gray cast iron guide rail,inspired by the bionic theory,varying forms ...In order to repair and reuse remaining quenching surface(RQS)divided into severely worn surface(SWun-S)and mildly worn surface(MWun-S)of abandoned gray cast iron guide rail,inspired by the bionic theory,varying forms of bionic units such as spot(Sp-S),striation(St-S),and reticulation(Re-S)were fabricated on RQS of gray cast iron through laser processing technology.Firstly,the microstructure,phase composition,and microhardness of bionic units and RQS were analyzed by optical microscopy as well as X-ray diffraction instrument and scanning electron microscopy,respectively.Secondly,the oil lubrication wear experiment was performed on homemade line reciprocating wear machine.The results demonstrated that the bionic units had a significant effect on improving wear resistance of RQS of abandoned guide rail due to the microstructure and higher hardness.In addition,the weight loss ratios of MWun-S,Sp-S,St-S,and Re-S samples were decreased by 36.72%,36.78%,62.26%,and 80.39%,respectively,compared with that of SWun-S sample.The mechanism of wear resistance enhancement was also discussed.展开更多
Gray cast iron that is used for automobile engine cylinder liners was laser surface hardened using Nd ： YAG quasi-continuous and CO2 continuous wave laser, respectively. The macromorphology and microstructure of the ...Gray cast iron that is used for automobile engine cylinder liners was laser surface hardened using Nd ： YAG quasi-continuous and CO2 continuous wave laser, respectively. The macromorphology and microstructure of the laser surface hardened layers were investigated using an optical microscope. Geometric dimensions including depth and width and microhardness distribution of the hardened layers were also examined in order to evaluate the quality of the hardened layers.展开更多
The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The th...The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The thin foils of the hardening layer worn down have been observed by electron microscopy.It was revealed that two types of martensite are strain-induced by slid- ing wearing under load of 1.72 MPa on the hardening layer of residual austenite.The strain induced martensite is profitable to improve the sliding wearing resistance.展开更多
Progress in the beam deflection technique opens up new possibilities for the application of electron beam (EB) surface and welding technologies in the automotive industry. This development is based on three-dimensiona...Progress in the beam deflection technique opens up new possibilities for the application of electron beam (EB) surface and welding technologies in the automotive industry. This development is based on three-dimensional high-speed beam deflection and fully automatic online process control. So, in the EB surface treatment three-dimensional energy transfer fields can be realised which take into account the contour of a component, the conditions of heat conduction and the load conditions. High flexibility, precision and reproducibility are typical characteristics. High productivity is achieved by the simultaneous interaction of the EB in several processing areas or by carrying out several processes simultaneously. EB surface treatment is becoming more and more attractive and important especially in the automotive industry, and also in comparison to laser technologies. This paper deals with different EB surface technologies, for example hardening, remelting, surface alloying, dispersing or cladding of different materials such as steel, cast iron and different alloys of Al, Mg and Ti. Examples of applications in the automotive industry, especially engine components, will be discussed.展开更多
基金Project(51101109)supported by the National Natural Science Foundation of China
文摘In order to improve the bonding strength between piston alloys and cast iron ring of aluminum piston with reinforced cast iron ring,the different methods of the surface treatments(shot blasting and sand blasting) to the cast iron ring are experimented.The optical micrograph shows that an intermetallic layer and a ligulate shaped structure are formed between piston alloys and cast iron base ring.After sand blasting treatment,the ring surface is non-metal shiny,matte-like and has no obvious pits.The intermetallic layer thickness formed between piston alloys and cast iron is thinner and more equally distributed after sand blasting to the ring.The content of the graphite distributed the interfacial zone after the shot blasting treatment is little.With the increase of time by sand blasting,the hardness starts to slightly descend.The bonding strength of the sample by sand blasting is obviously higher than that by shot blasting and increases from 9.32 MPa to 19.53 MPa.
基金financially supported by the Key Project of China National Erzhong Group Co.(No.2012zx04010-081)
文摘The surface of nodular cast iron （NCI） with a ferrite substrate was rapidly remelted and solidified by plasma transferred arc （PTA） to induce a chilled structure with high hardness and favorable wear resistance. The effect of scanning speed on the microstructure, micro-hardness distribution, and wear properties of PTA-remelted specimens was systematically investigated. Microstructural characterization in-dicated that the PTA remelting treatment could dissolve most graphite nodules and that the crystallized primary austenite dendrites were transformed into cementite, martensite, an interdendritic network of ledeburite eutectic, and certain residual austenite during rapid solidifica-tion. The dimensions of the remelted zone and its dendrites increase with decreased scanning speed. The microhardness of the remelted zone varied in the range of 650 HV0.2 to 820 HV0.2, which is approximately 2.3-3.1 times higher than the hardness of the substrate. The wear re-sistance of NCI was also significantly improved after the PTA remelting treatment.
基金supported by Project 985-High Performance Materials of Jilin UniversityProject 985-Bionic Engineering Science and Technology Innovationdouble first-class project by Jilin Province and Jilin University(SXGJXX2017-14).
文摘In order to repair and reuse remaining quenching surface(RQS)divided into severely worn surface(SWun-S)and mildly worn surface(MWun-S)of abandoned gray cast iron guide rail,inspired by the bionic theory,varying forms of bionic units such as spot(Sp-S),striation(St-S),and reticulation(Re-S)were fabricated on RQS of gray cast iron through laser processing technology.Firstly,the microstructure,phase composition,and microhardness of bionic units and RQS were analyzed by optical microscopy as well as X-ray diffraction instrument and scanning electron microscopy,respectively.Secondly,the oil lubrication wear experiment was performed on homemade line reciprocating wear machine.The results demonstrated that the bionic units had a significant effect on improving wear resistance of RQS of abandoned guide rail due to the microstructure and higher hardness.In addition,the weight loss ratios of MWun-S,Sp-S,St-S,and Re-S samples were decreased by 36.72%,36.78%,62.26%,and 80.39%,respectively,compared with that of SWun-S sample.The mechanism of wear resistance enhancement was also discussed.
文摘Gray cast iron that is used for automobile engine cylinder liners was laser surface hardened using Nd ： YAG quasi-continuous and CO2 continuous wave laser, respectively. The macromorphology and microstructure of the laser surface hardened layers were investigated using an optical microscope. Geometric dimensions including depth and width and microhardness distribution of the hardened layers were also examined in order to evaluate the quality of the hardened layers.
文摘The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The thin foils of the hardening layer worn down have been observed by electron microscopy.It was revealed that two types of martensite are strain-induced by slid- ing wearing under load of 1.72 MPa on the hardening layer of residual austenite.The strain induced martensite is profitable to improve the sliding wearing resistance.
文摘Progress in the beam deflection technique opens up new possibilities for the application of electron beam (EB) surface and welding technologies in the automotive industry. This development is based on three-dimensional high-speed beam deflection and fully automatic online process control. So, in the EB surface treatment three-dimensional energy transfer fields can be realised which take into account the contour of a component, the conditions of heat conduction and the load conditions. High flexibility, precision and reproducibility are typical characteristics. High productivity is achieved by the simultaneous interaction of the EB in several processing areas or by carrying out several processes simultaneously. EB surface treatment is becoming more and more attractive and important especially in the automotive industry, and also in comparison to laser technologies. This paper deals with different EB surface technologies, for example hardening, remelting, surface alloying, dispersing or cladding of different materials such as steel, cast iron and different alloys of Al, Mg and Ti. Examples of applications in the automotive industry, especially engine components, will be discussed.
