Lubricant for metallurgical powder composition
AssigneeHöganäs AB
InventorHilmar Vidarsson
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Abstract
This invention relates to a lubricant for metallurgical powder compositions. According to the invention, the lubricant contains a polyolefine-based polymer, which has a weight-average molecular weight Mw of 500-10000. The invention further concerns a metal-powder composition containing the lubricant, method for making sintered products by using the lubricant, and use of the same in cold and warm compaction.
Claims19
A metal-powder composition for compaction containing metal powder and a lubricant comprising a polyolefin polymer which has a weight-average molecular weight Mw of 500 to 10,000, said lubricant having a polydispersity Mw/Mn lower than 2.5.
A method for making sintered products, comprising the steps of:
- a) mixing a metal powder and a lubricant to a metal-powder composition;
- b) compacting the metal-powder composition to a compacted body;
- c) sintering the compacted body wherein the lubricant comprises a polyolefin polymer, which has a weight-average molecular weight Mw of 500 to 10,000, said lubricant having a polydispersity Mw/Mn lower than 2.5;
- and
- d) before step c), heating the compacted body to a temperature above the melting point peak of the polyolefin lubricant for a sufficient period of time to obtain essentially the same temperature in the entire compacted body.
A method for making sintered products, comprising the steps of:
- a) mixing a metal powder and a lubricant to a metal-powder composition,
- b) preheating the metal-powder composition to a predetermined temperature,
- c) compacting the heated metal-powder composition in a heated tool, and
- d) sintering the compacted metal-powder composition, wherein the lubricant comprises a polyolefin polymer, which has a weight-average molecular weight Mw of 1,000 to 10,000.
A metal-powder composition for compaction containing metal powder and a lubricant comprising a polyolefin polymer, which has a weight-average molecular weight Mw of 1,000 to 10,000, said lubricant having a polydispersity Mw/Mn lower than 1.5.
The metal-powder composition as claimed in 5, wherein the lubricant makes up 0.2 to 0.8% by weight of the total composition.
Dependencies are inferred from the claim text.