1992 Vol.5(2)
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1992, 6(2).
Abstract:
The author proposes the principle of automatic shape generation by the manufacturing process simulation. A combined geometric representation has been founded for the realization of the principle in practice. The algorithms of the interference-free offset and the 3D object sweep have been invented to generate the CL data, the draft and blending surfaces of the compound sculptured shapes. Based on the new concept the author has developed an integrated CAD/CAM sytem that is different from the conventional study. Some examples are to show the successful applications in the complicated die & mould.
The author proposes the principle of automatic shape generation by the manufacturing process simulation. A combined geometric representation has been founded for the realization of the principle in practice. The algorithms of the interference-free offset and the 3D object sweep have been invented to generate the CL data, the draft and blending surfaces of the compound sculptured shapes. Based on the new concept the author has developed an integrated CAD/CAM sytem that is different from the conventional study. Some examples are to show the successful applications in the complicated die & mould.
1992, 6(2).
Abstract:
This paper first confirms, by means of microscopic analysis, that primary carbides of high manganese steel are formed during solidification in liquid-quenching test and that the carbides can grow with the formation of branched facets because of the activated trace elements oxygen and sulphur adsorbed on the growth interface. The carbide is lath-shaped under a slight supercooling. By adding some modifying agents, the lathy carbide will turn into nodular shape because of the decrease in the content of oxygen and sulphur distributed on the growth interface of carbide and the increase in the amount of supercooling. These results will provide a theoritical and experimental basis for developing new type manganese steels.
This paper first confirms, by means of microscopic analysis, that primary carbides of high manganese steel are formed during solidification in liquid-quenching test and that the carbides can grow with the formation of branched facets because of the activated trace elements oxygen and sulphur adsorbed on the growth interface. The carbide is lath-shaped under a slight supercooling. By adding some modifying agents, the lathy carbide will turn into nodular shape because of the decrease in the content of oxygen and sulphur distributed on the growth interface of carbide and the increase in the amount of supercooling. These results will provide a theoritical and experimental basis for developing new type manganese steels.
1992, 6(2).
Abstract:
The substructure coupling of FEM for solving the transient temperature and thermal stress fields in large axisymmetric structure such as turbine rotor by microcomputer and FEM-BEM method for calculating local concentrical stresses are presented. The numerical implementations are correpondly disscussed in detail. The computer programs are developed and used for analysising the cold start-up procedures of some turbine rotor.
The substructure coupling of FEM for solving the transient temperature and thermal stress fields in large axisymmetric structure such as turbine rotor by microcomputer and FEM-BEM method for calculating local concentrical stresses are presented. The numerical implementations are correpondly disscussed in detail. The computer programs are developed and used for analysising the cold start-up procedures of some turbine rotor.
1992, 6(2).
Abstract:
The authors have extablished a Die Steels Database and designed the applied software. This system consists of several modules. It collects, compiles and stores a variety of data for die steels. This paper describes the structure and functions of the system and some examples are given. Applying the database and the CAD system, users can select the suitable die steels and design the optimum heat treatment processes quickly. It has been confirmed that this system can be operated conveniently and reliablely and mastered easily.
The authors have extablished a Die Steels Database and designed the applied software. This system consists of several modules. It collects, compiles and stores a variety of data for die steels. This paper describes the structure and functions of the system and some examples are given. Applying the database and the CAD system, users can select the suitable die steels and design the optimum heat treatment processes quickly. It has been confirmed that this system can be operated conveniently and reliablely and mastered easily.
1992, 6(2).
Abstract:
This paper presents a new type of gear transmission, the quasi-ellipsoidal gear transmission with inner-toroidal teeth. According to the double DOF conjugate surface theory, the function of the transmission ratio is derived. The pitch surfaces which satisfy the meshing conditions in the whole meshing zone can be obtained easily. The tooth profile of the inner-toroidal rotatary surfaces have high contact strength and can satisfy no pointing of addendum. This type of transmission is very suitable for the precise flexibel joint of robot.
This paper presents a new type of gear transmission, the quasi-ellipsoidal gear transmission with inner-toroidal teeth. According to the double DOF conjugate surface theory, the function of the transmission ratio is derived. The pitch surfaces which satisfy the meshing conditions in the whole meshing zone can be obtained easily. The tooth profile of the inner-toroidal rotatary surfaces have high contact strength and can satisfy no pointing of addendum. This type of transmission is very suitable for the precise flexibel joint of robot.
1992, 6(2).
Abstract:
This effect of vane shape on centrifugal pump performance are studied. The load on vane surface caused the generation of secondary flow within impeller, which, in ture, has the great effect on the development of boundary layer on suction surface at exit and therefore on the pump performance. These should be taken into consideration in the pump design.
This effect of vane shape on centrifugal pump performance are studied. The load on vane surface caused the generation of secondary flow within impeller, which, in ture, has the great effect on the development of boundary layer on suction surface at exit and therefore on the pump performance. These should be taken into consideration in the pump design.
1992, 6(2).
Abstract:
This paper presents the measurement of the electron density of laser, TIG welding arc, and laser + TIG welding arc plasma by the method of Stark Broadened Linewidth. The reason why electric arc enhances laser welding is that the electric arc can dilute the electron density of laser plasma, weaken the ability of laser plasma to absorb and reflect the laser energy, and improve the hot-working efficiency of laser beams. Experiments prove that the combined action of arc and laser beams can obviously improve the weld penetration in welding.
This paper presents the measurement of the electron density of laser, TIG welding arc, and laser + TIG welding arc plasma by the method of Stark Broadened Linewidth. The reason why electric arc enhances laser welding is that the electric arc can dilute the electron density of laser plasma, weaken the ability of laser plasma to absorb and reflect the laser energy, and improve the hot-working efficiency of laser beams. Experiments prove that the combined action of arc and laser beams can obviously improve the weld penetration in welding.
1992, 6(2).
Abstract:
This paper analyses the effects of the changes of the tool's rake and clearance angles on the dynamic behavior of the cutting process from the energy point of view. Based on the theoretical analysis, the experimental investigations on restraining chatter are made. A new method for suppressing chatter by on-line adjusting tool geometric angles is presented.
This paper analyses the effects of the changes of the tool's rake and clearance angles on the dynamic behavior of the cutting process from the energy point of view. Based on the theoretical analysis, the experimental investigations on restraining chatter are made. A new method for suppressing chatter by on-line adjusting tool geometric angles is presented.
1992, 6(2).
Abstract:
The comparison tests have been done on the butt joints of A131 and A537 steeis welded with the same kind of electrode LB52NS. The conclusion has been obtained from the tests that the arrest crack property of the welded joints of A131 steel with relatively high strength matching is better than that of the welded jionts of A537 steel with relatively low strength matching. From the statistics analysis it has shown that either the DTE or the As% conforms with normal distributions. Based upon Green Integration a new method for calculating As% was proposed.
The comparison tests have been done on the butt joints of A131 and A537 steeis welded with the same kind of electrode LB52NS. The conclusion has been obtained from the tests that the arrest crack property of the welded joints of A131 steel with relatively high strength matching is better than that of the welded jionts of A537 steel with relatively low strength matching. From the statistics analysis it has shown that either the DTE or the As% conforms with normal distributions. Based upon Green Integration a new method for calculating As% was proposed.
1992, 6(2).
Abstract:
This paper is to introduce a new type of self-lubricating sliding bearings of SPF composites. The test results showed that the performance of SPF bearings offers many advantages over the famous DU bearings such as high load-carrying capacity and limiting PV value. Good resistance of wear, long life of service as well as good lubricating property at high temperature. More over, the manufacturing process of SPF bearings is simpler than that of DU bearings. Therefore, it is a kind of ideal self-lubricating sliding bearings. The static characteristic of bearings and affecting factors. The mechanism of reducing friction and wear as well as the case of field test running have been discussed in this paper.
This paper is to introduce a new type of self-lubricating sliding bearings of SPF composites. The test results showed that the performance of SPF bearings offers many advantages over the famous DU bearings such as high load-carrying capacity and limiting PV value. Good resistance of wear, long life of service as well as good lubricating property at high temperature. More over, the manufacturing process of SPF bearings is simpler than that of DU bearings. Therefore, it is a kind of ideal self-lubricating sliding bearings. The static characteristic of bearings and affecting factors. The mechanism of reducing friction and wear as well as the case of field test running have been discussed in this paper.
1992, 6(2).
Abstract:
In deep hole drilling, the power consumption of the main spindle motor is a good indirect reflection of the circumstances in the drilling zone. In this paper, the changes in the patterns of the power signals during normal and abnormal drilling processes are experimentally investigated. The characteristic extraction method and some problems associated with real time detection are analyzed and discussed. A microcomputer based monitoring system is established and the abnormal states detection in deep hole drilling is initially realized.
In deep hole drilling, the power consumption of the main spindle motor is a good indirect reflection of the circumstances in the drilling zone. In this paper, the changes in the patterns of the power signals during normal and abnormal drilling processes are experimentally investigated. The characteristic extraction method and some problems associated with real time detection are analyzed and discussed. A microcomputer based monitoring system is established and the abnormal states detection in deep hole drilling is initially realized.
1992, 6(2).
Abstract:
Studies were made on the mechanical properties obtained after aging at 540～600℃ for 0～5000h and 570℃ creep hardness of the heat-resisting steels 20Crf1Mo1VTiB and 20Cr12MoWV(C422), which had been oil-quenched from 1050℃, temperd at 700℃ for 4h. It was established that the comprehensive mechanical properties and high temperature stability of 20Cr1Mo1VTiB steel are supperior to those of C422 steel under the conditions of the present research. As the L-M parameter P=T(20+lgt) increases, both strength and hardness of the above steels decrease linearly along a broken line with two different slopes. In the same way, the creep hardness of the above steels decrease as the holding time lgt(s) at 570℃ increases. Corresponding linear equations were obtained, by making use of which it is possible to predict long-time properties from short-time properties.
Studies were made on the mechanical properties obtained after aging at 540～600℃ for 0～5000h and 570℃ creep hardness of the heat-resisting steels 20Crf1Mo1VTiB and 20Cr12MoWV(C422), which had been oil-quenched from 1050℃, temperd at 700℃ for 4h. It was established that the comprehensive mechanical properties and high temperature stability of 20Cr1Mo1VTiB steel are supperior to those of C422 steel under the conditions of the present research. As the L-M parameter P=T(20+lgt) increases, both strength and hardness of the above steels decrease linearly along a broken line with two different slopes. In the same way, the creep hardness of the above steels decrease as the holding time lgt(s) at 570℃ increases. Corresponding linear equations were obtained, by making use of which it is possible to predict long-time properties from short-time properties.
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