For an ultra-high-pressure hydraulic transmission system of a large-size hydraulic forging press(LHFP),a 70 MPa two-way proportional cartridge valve has been developed to improve the power weight ratio of the hydrauli...For an ultra-high-pressure hydraulic transmission system of a large-size hydraulic forging press(LHFP),a 70 MPa two-way proportional cartridge valve has been developed to improve the power weight ratio of the hydraulic forging press.In this study,a nominal diameter 25 mm(DN25)cartridge valve is taken as the research object.A longer concentric cylindrical annular gap is set to effectively prevent the ultra-high-pressure oil from flowing to the pilot stage and a seated valve structure is set to form the linear sealing zone in the closing state of the main valve port.Electric-displacement feedback is adopted to realize precise control of the main valve port flow and the features of this valve are investigated.In order to verify the strength and static and dynamic characteristics,the finite element model and a simulation model of the valve proposed above are built.There is a little deformation which does not affect the main valve spool movement,and the main valve port flow meets the design demands.Then,the prototype of DN2570 TPCV is manufactured and a ultra-high-pressure experimental platform is developed.The experimental results show that the DN2570 TPCV designed in this study has the advantage of fast response,high control precision,and low leakage,which can meet the requirements of LHFPs.展开更多
The problem of insufficient hardenability in general large-size parts always occurs in product manufacturing because of their large size,etc.It is restricted mainly by its own alloy composition with micro-alloy and ke...The problem of insufficient hardenability in general large-size parts always occurs in product manufacturing because of their large size,etc.It is restricted mainly by its own alloy composition with micro-alloy and key quenching and partitioning(Q&P) process.The relationship between the cooling rate and properties of small samples was analyzed as the basis of the initial cooling rate at different positions corresponding to large-size parts combined with controlled austenization temperature in this work.Typical as-treated micro structure after a fast cooling rate is mainly composed of lath bainite,martensite,and retained austenite(RA),while bainite and RA after a slow cooling rate.Simulations showed that cooling control via decreasing spray intensity,meeting higher strength at the surface,and good strength and toughness match can be obtained both at the surface and in the center.As-treated large ring part has~1330 MPa tensile strength and~95 J impact energy at the surface,and meantime,~1191 MPa tensile strength and~70 J impact energy in the center,which narrows the property difference.展开更多
基金Supported by the Natural Science Foundation of Hebei Province(E2018203028)。
文摘For an ultra-high-pressure hydraulic transmission system of a large-size hydraulic forging press(LHFP),a 70 MPa two-way proportional cartridge valve has been developed to improve the power weight ratio of the hydraulic forging press.In this study,a nominal diameter 25 mm(DN25)cartridge valve is taken as the research object.A longer concentric cylindrical annular gap is set to effectively prevent the ultra-high-pressure oil from flowing to the pilot stage and a seated valve structure is set to form the linear sealing zone in the closing state of the main valve port.Electric-displacement feedback is adopted to realize precise control of the main valve port flow and the features of this valve are investigated.In order to verify the strength and static and dynamic characteristics,the finite element model and a simulation model of the valve proposed above are built.There is a little deformation which does not affect the main valve spool movement,and the main valve port flow meets the design demands.Then,the prototype of DN2570 TPCV is manufactured and a ultra-high-pressure experimental platform is developed.The experimental results show that the DN2570 TPCV designed in this study has the advantage of fast response,high control precision,and low leakage,which can meet the requirements of LHFPs.
基金financially supported by the Fundamental Research Funds for the Central Universities (No. 2019JBZ103)。
文摘The problem of insufficient hardenability in general large-size parts always occurs in product manufacturing because of their large size,etc.It is restricted mainly by its own alloy composition with micro-alloy and key quenching and partitioning(Q&P) process.The relationship between the cooling rate and properties of small samples was analyzed as the basis of the initial cooling rate at different positions corresponding to large-size parts combined with controlled austenization temperature in this work.Typical as-treated micro structure after a fast cooling rate is mainly composed of lath bainite,martensite,and retained austenite(RA),while bainite and RA after a slow cooling rate.Simulations showed that cooling control via decreasing spray intensity,meeting higher strength at the surface,and good strength and toughness match can be obtained both at the surface and in the center.As-treated large ring part has~1330 MPa tensile strength and~95 J impact energy at the surface,and meantime,~1191 MPa tensile strength and~70 J impact energy in the center,which narrows the property difference.
