US2003177866A1PendingUtilityA1

Agglomerated stainless steel powder compositions and methods for making same

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Assignee: OMG AMERICAS INCPriority: Mar 22, 2002Filed: Mar 22, 2002Published: Sep 25, 2003
Est. expiryMar 22, 2022(expired)· nominal 20-yr term from priority
Inventors:Nic VeloffPrasan K. Samal
B22F 1/148B22F 1/10B22F 2009/0828B22F 2998/10
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Claims

Abstract

An agglomerated stainless steel powder composition for use in rigid-die powder metallurgy is provided. The composition preferably comprises a pre-alloyed water atomized stainless steel powder and a water-soluble binder. It exhibits minimal dusting, segregation, and die galling, has good compressibility and flow rate, and produces a finished part essentially free of non-metal residues. Methods for making this agglomerated stainless steel powder composition are also provided. Improved stainless steel rigid-die powder metallurgical parts are also provided.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . An agglomerated stainless steel powder composition comprising: 
 (a) a pre-alloyed water atomized stainless steel powder; and    (b) a water-soluble binder, wherein the water-soluble binder is between about 0.05% and about 2.0% by weight of the agglomerated stainless steel powder composition based on the weight of the agglomerated stainless steel powder.    
     
     
         2 . A composition according to  claim 1 , wherein the composition is substantially free of water.  
     
     
         3 . A composition according to  claim 1 , wherein the atomized stainless steel powder comprises a 400 series stainless steel alloy or a 300 series stainless steel alloy.  
     
     
         4 . A composition according to  claim 1 , wherein the atomized stainless steel powder comprises at least 35% by weight −325 mesh particles.  
     
     
         5 . A composition according to  claim 4 , wherein the atomized stainless steel powder comprises between about 35% and about 70% by weight −325 mesh particles.  
     
     
         6 . A composition according to  claim 5 , wherein the atomized stainless steel powder comprises between about 50% and about 70% by weight −325 mesh particles.  
     
     
         7 . A composition according to  claim 1 , wherein the water-soluble binder is an alginate.  
     
     
         8 . A composition according to  claim 1 , wherein the water-soluble binder is methylcellulose.  
     
     
         9 . A composition according to  claim 1 , further comprising a lubricant.  
     
     
         10 . A composition according to  claim 9 , wherein the lubricant is selected from the group consisting of waxes and stearates.  
     
     
         11 . A composition according to  claim 9 , wherein the lubricant is an anti-static internal lubricant.  
     
     
         12 . A method of preparing a dry agglomerated stainless steel powder composition comprising the steps of: 
 (a) mixing an atomized stainless steel powder with a water-soluble binder and water to form an admixture; and    (b) drying the admixture to form the dry agglomerated stainless steel powder composition.    
     
     
         13 . A method according to  claim 12 , wherein the atomized stainless steel powder is obtained by atomizing a stainless steel melt-stock with water to produce the atomized stainless steel powder.  
     
     
         14 . A method according to  claim 12 , wherein the atomized stainless steel powder comprises a 400 series stainless steel alloy or a 300 series stainless steel alloy.  
     
     
         15 . A method according to  claim 12 , wherein the atomized stainless steel powder comprises at least 35% by weight −325 mesh particles.  
     
     
         16 . A method according to  claim 15 , wherein the atomized stainless steel powder comprises between about 35% and about 70% by weight −325 mesh particles.  
     
     
         17 . A method according to  claim 16 , wherein the atomized stainless steel powder comprises between about 50% and about 70% by weight −325 mesh particles.  
     
     
         18 . A method according to  claim 12 , wherein the water-soluble binder is an alginate.  
     
     
         19 . A method according to  claim 12 , wherein the water-soluble binder is methylcellulose.  
     
     
         20 . A method according to  claim 14 , wherein the water-soluble binder is between about 0.05% and about 2% by weight of the agglomerated stainless steel powder composition.  
     
     
         21 . A method according to  claim 14 , wherein the amount of water mixed is between about 5% and about 20% by weight of the atomized stainless steel powder.  
     
     
         22 . A method according to  claim 14 , further comprising the step of screening the dry powder composition through a mesh.  
     
     
         23 . A stainless steel part made from the composition of  claim 1.

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