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A novel gas atomization nozzle for liquid metal atomization
Development of a device, sensitive to the various species evolved was reported together with a description of its use in the control of debinding. The principles of the device were outlined. The cost was shown to be low and the technique was considered to have potential for control of industrial debinding of MIM parts. SOLVENT DEBINDING OF INJECTION MOULDED PARTS WITH SUPERCRITICAL CARBON DIOXIDE T. Shimizu et al. (Uthonomiya University, Japan.) The use of liquid COs, under high pressures, as a debinding solvent, was reported. The liquid dissolves wax selectively. A part, 5 mm in thickness, was reported to have been debound in less than 1 hour. The potential of the method was discussed. METAL INJECTION MOULDING OF INVAR SYN’. NILVAR ABose. (Parmatech Corp, Petaluma, California, USA) Ni-Fe alloys were reviewed with reference to low thermal expansion in some alloys and applications of these, notably Invar. The feasibility of using MIM to make parts in these alloys was discussed. Preliminary investigations of Invar were described. MECHANICAL AND THERMAL PROPERTIES OF INJECTION MOULDED ALUMINA CERAMICS M.Youseffi, IAMenzies. (University of Technology, Loughborough, UX.) The mechanical and thermal properties of injection moulded 88%, 95% and 99.5% pure AlsOs were investigated. Two different binder systems were used. It was reported that the propekes were similar to those of pressed and sintered specimens. CORRELATION OF SMALL PUNCH TESTS WITH TENSILE TESTS ON IRONALUMINIUM-SILICON B.LLograsso et al (Ames Laboratory, USA) Measurement of mechanical properties of injection moulded parts was discussed with regard to difficulties imposed by small sizes and complex shapes. An investigation to establish a relationship between tensile tests and small punch tests for a range of Fe base alloys was described. A relationship was established between the results for a biaxial punch test, tensile tests and structure and to provide and alternative to tensile testing. COMPOSITE PARTS BY INJECTION MOULDING R.M.German et al. (Pennsylvania University, Pennsylvania, USA)
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Combination of different materials in a single part was discussed. An investigation to produce a bi-metallic parts by metal injection moulding was described. problems of adjusting process parameters for a tool steel and a Ni-steel were outlined. Dilatometry studies were used to establish process conditions. A sample part was discussed. SINTERING CHARACTERISTICS OF INJECTION MOULDED STAINLESS STEEL N.H.Loh, X.I.Khar. (Nanyang Technical University, Singapore.) Advantages of the use of MIM to make parts were discussed. An investigation of the sintering of a 316L stainless steel, heated at 5 to 15”C/min to 1050 to 1350°C for 1 to 2 hours, was described. Properties were measured. Maximum shrinkage was 16.5%, maximum density was 98.4%. Most shrinkage occurred at 1050 to 1200°C. Sinterlng was reported to be enhanced by slow heating and maximum temperature. 1.4% open porosity was measured.
Sintering controls PREDICTION OF PART TEMPERATURE PROFILE DURING SINTERING UNDERF PRODUCTION CONDITIONS J.Dwyer et al. (BOC Group Technical Centre, USA) Part temperature and thermal profile during sintering were reviewed with regard to effects. The need to know optimum values for a given part as influenced by belt speed in continuous furnaces and temperature were noted. A PC based model, which predicts part temperature as a function of part characteristics and process conditions was described. The controlling thermal balance equation and use of the model in production conditions were described. Predictions were verified experimentally. Applications were discussed. A COST-EFFECTIVE PREVENTIVE MAINTAINANCE PROGRAMME FOR SINTERING FURNACES G.M.Mayer, T.M.Cadle. (Zenith Sintered Products, Inc., Germantown, USA) It was reported that a preventive maintainance process had been developed for avoidance of interuption to production and prevention of production of out-ofcompliance parts. Emphasis was placed on repair-not-replacement. The technique is designed to supplement existing methods which, while reliable, require expensive equipment and are time consuming. The new methods and shown to, be easily adopted and reliable. An instrument to measure gas flow rates was repoked to aid in monitoring of sinterhardening.
REMOTE ELECTRONIC MANAGEMENT OF SINTERING FURNACES J.Dwyer et al. (BOC Group Technical Centre, USA) A PC based system for monitoring and storage of data concerning factors which control sintering furnaces was described. The system provides access to historical and real time furnace data through a model. The software is shown to be capable of linking hot-spots to sensor locations on furnace diagrams.
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PRODUCTION OF FINE PREALLOYED POWDERS FOR MIM BY ‘NANOVEL’ GAS ATOMIZATION PROCESS GSchulz. (Nanoval AG, Germany.) Factors which limit the production of fine powders for MIM were identified and discussed. It was reported that the NANOVEL gas atomization process produced powder which did not require screening for MIM and used 33% of the gas needed for conventional atomization. PREDICTIVE COMPUTATIONAL FLUID DYNAMICS OF CLOSE COUPLED ATOMIZARION DIE R.Makineau, R.A.Berry. (Idaho National Engineering Laboratory, USA) The paper described a predictive 2 dimensional axisymmetric computational fluid dynamics model of close coupled gas atomization. The simulation was carried out for Ar and N atomization of a Ni base alloy and used to optimize for minimal gas consumption and maximum powder yield. Predicted and experimental results were compared. A NOVEL GAS ATOMIZATION NOZZLE FOR LIQUID METAL ATOMIZATION I.E.Anderson et al. (Ames Laboratory, USA.) A novel nozzle for close coupled high pressure gas atomization was described. It was reported that a high yield of fine powder was produced. A comparison was made with other processes in respect of gas flow, gas and metal consumption ratios and powder particle size distribution. The resunlts were discussed. CHARACTERIZATION OF LIQUID BREAKUP MECHANISMS FOR ATOMIZATION NOZZLES S.P.Mates, G.S.Settles. (Pennsylvania State University, Pennsylvania, USA) It was reported that several gas atomization nozzles had been characterized using flow visualization techniques with respect to primary disintegration of the metal stream. For each nozzle two mechanisms were MPR March 1997
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State
Combination of different materials in a single part was discussed. An investigation to produce a bi-metallic parts by metal injection moulding was described. problems of adjusting process parameters for a tool steel and a Ni-steel were outlined. Dilatometry studies were used to establish process conditions. A sample part was discussed. SINTERING CHARACTERISTICS OF INJECTION MOULDED STAINLESS STEEL N.H.Loh, X.I.Khar. (Nanyang Technical University, Singapore.) Advantages of the use of MIM to make parts were discussed. An investigation of the sintering of a 316L stainless steel, heated at 5 to 15”C/min to 1050 to 1350°C for 1 to 2 hours, was described. Properties were measured. Maximum shrinkage was 16.5%, maximum density was 98.4%. Most shrinkage occurred at 1050 to 1200°C. Sinterlng was reported to be enhanced by slow heating and maximum temperature. 1.4% open porosity was measured.
Sintering controls PREDICTION OF PART TEMPERATURE PROFILE DURING SINTERING UNDERF PRODUCTION CONDITIONS J.Dwyer et al. (BOC Group Technical Centre, USA) Part temperature and thermal profile during sintering were reviewed with regard to effects. The need to know optimum values for a given part as influenced by belt speed in continuous furnaces and temperature were noted. A PC based model, which predicts part temperature as a function of part characteristics and process conditions was described. The controlling thermal balance equation and use of the model in production conditions were described. Predictions were verified experimentally. Applications were discussed. A COST-EFFECTIVE PREVENTIVE MAINTAINANCE PROGRAMME FOR SINTERING FURNACES G.M.Mayer, T.M.Cadle. (Zenith Sintered Products, Inc., Germantown, USA) It was reported that a preventive maintainance process had been developed for avoidance of interuption to production and prevention of production of out-ofcompliance parts. Emphasis was placed on repair-not-replacement. The technique is designed to supplement existing methods which, while reliable, require expensive equipment and are time consuming. The new methods and shown to, be easily adopted and reliable. An instrument to measure gas flow rates was repoked to aid in monitoring of sinterhardening.
REMOTE ELECTRONIC MANAGEMENT OF SINTERING FURNACES J.Dwyer et al. (BOC Group Technical Centre, USA) A PC based system for monitoring and storage of data concerning factors which control sintering furnaces was described. The system provides access to historical and real time furnace data through a model. The software is shown to be capable of linking hot-spots to sensor locations on furnace diagrams.
A tomb
tion
PRODUCTION OF FINE PREALLOYED POWDERS FOR MIM BY ‘NANOVEL’ GAS ATOMIZATION PROCESS GSchulz. (Nanoval AG, Germany.) Factors which limit the production of fine powders for MIM were identified and discussed. It was reported that the NANOVEL gas atomization process produced powder which did not require screening for MIM and used 33% of the gas needed for conventional atomization. PREDICTIVE COMPUTATIONAL FLUID DYNAMICS OF CLOSE COUPLED ATOMIZARION DIE R.Makineau, R.A.Berry. (Idaho National Engineering Laboratory, USA) The paper described a predictive 2 dimensional axisymmetric computational fluid dynamics model of close coupled gas atomization. The simulation was carried out for Ar and N atomization of a Ni base alloy and used to optimize for minimal gas consumption and maximum powder yield. Predicted and experimental results were compared. A NOVEL GAS ATOMIZATION NOZZLE FOR LIQUID METAL ATOMIZATION I.E.Anderson et al. (Ames Laboratory, USA.) A novel nozzle for close coupled high pressure gas atomization was described. It was reported that a high yield of fine powder was produced. A comparison was made with other processes in respect of gas flow, gas and metal consumption ratios and powder particle size distribution. The resunlts were discussed. CHARACTERIZATION OF LIQUID BREAKUP MECHANISMS FOR ATOMIZATION NOZZLES S.P.Mates, G.S.Settles. (Pennsylvania State University, Pennsylvania, USA) It was reported that several gas atomization nozzles had been characterized using flow visualization techniques with respect to primary disintegration of the metal stream. For each nozzle two mechanisms were MPR March 1997
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