Lubricant is harmful to the mechanical properties of the sintered materials. Die wall lubrication was applied on warm compaction powder metallurgy in the hope of reducing the concentration level of the admixed lubrica...Lubricant is harmful to the mechanical properties of the sintered materials. Die wall lubrication was applied on warm compaction powder metallurgy in the hope of reducing the concentration level of the admixed lubricant. Iron based samples were prepared by die wall lubricated warm compaction at 175 ℃, using a compacting pressure of 550 MPa. Emulsified polytetrafluoroethylene(PTFE) was used as die wall lubricant. Admixed lubricant concentration ranging from 0 to 0.5% was tested. Extremely low admixed lubricant contents were used. Results show that in addition to the decrease in ejection forces, the green density of the compacts increases with the decrease of admixed lubricant content until it reaches the maximum at 0.06% of lubricant content, then decreases with the decrease of admixed lubricant content. The mechanical properties of the sintered compacts that contain more than 0.06% admixed lubricant are better than those of the samples that contain lesser lubricant. No scoring was observed in all die wall lubricated experiments.展开更多
Iron-based powder metallurgy material was prepared by warm compaction at 125 ℃ using a compacting pressure of 700 MPa. Sintering temperature ranging from 1 100 ℃ to 1 300 ℃ and sintering time ranging from 40 min to...Iron-based powder metallurgy material was prepared by warm compaction at 125 ℃ using a compacting pressure of 700 MPa. Sintering temperature ranging from 1 100 ℃ to 1 300 ℃ and sintering time ranging from 40 min to 80 min were used to study the effects of sintering parameters on the compacts. Die wall lubrication polytetrafluoroethylene(PTFE) emulsion was also applied in combination with warm compaction in hope to increase the compact density and the mechanical properties of the sintered material. Green and sintered density, spring back effect and sinter shrinkage were measured. Mechanical properties of both as-sinter and heat treated samples were also measured. Results show that mechanical properties of the sintered compacts increase with the increase of sintering temperature and sintering time. Sample prepared by die wall lubricated warm compaction always shows higher density and mechanical properties.展开更多
文摘Lubricant is harmful to the mechanical properties of the sintered materials. Die wall lubrication was applied on warm compaction powder metallurgy in the hope of reducing the concentration level of the admixed lubricant. Iron based samples were prepared by die wall lubricated warm compaction at 175 ℃, using a compacting pressure of 550 MPa. Emulsified polytetrafluoroethylene(PTFE) was used as die wall lubricant. Admixed lubricant concentration ranging from 0 to 0.5% was tested. Extremely low admixed lubricant contents were used. Results show that in addition to the decrease in ejection forces, the green density of the compacts increases with the decrease of admixed lubricant content until it reaches the maximum at 0.06% of lubricant content, then decreases with the decrease of admixed lubricant content. The mechanical properties of the sintered compacts that contain more than 0.06% admixed lubricant are better than those of the samples that contain lesser lubricant. No scoring was observed in all die wall lubricated experiments.
文摘Iron-based powder metallurgy material was prepared by warm compaction at 125 ℃ using a compacting pressure of 700 MPa. Sintering temperature ranging from 1 100 ℃ to 1 300 ℃ and sintering time ranging from 40 min to 80 min were used to study the effects of sintering parameters on the compacts. Die wall lubrication polytetrafluoroethylene(PTFE) emulsion was also applied in combination with warm compaction in hope to increase the compact density and the mechanical properties of the sintered material. Green and sintered density, spring back effect and sinter shrinkage were measured. Mechanical properties of both as-sinter and heat treated samples were also measured. Results show that mechanical properties of the sintered compacts increase with the increase of sintering temperature and sintering time. Sample prepared by die wall lubricated warm compaction always shows higher density and mechanical properties.
