Aqueous lubricant for plactic working of metallic material and method of lubricant film processing

Abstract

A waterborne lubricant, useful in the plastic working of metals, which imparts a lubricating behavior to the surface of metals in the absence of a conversion coating contains (A) water-soluble inorganic salt, (B) lubricating agent selected from molybdenum disulfide and graphite, and (C) wax wherein these components are dissolved or dispersed in water, the (B)/(A) solids weight ratio is 1.0 to 5.0, and the (C)/(A) solids weight ratio is 0.1 to 1.0. The water-soluble inorganic salt (A) can be selected from the sulfates, silicates, borates, molybdates, and tungstates. The wax (C) can be a water-dispersed natural or synthetic wax having a melting point of 70 to 150° C. A lubricating coating is formed by application to give a post-drying add-on of 0.5 to 40 g/m2. A method for using said lubricant is also provided.

We claim:  
     
         1 . A waterborne lubricant useful in the plastic working of metals, comprising: 
 (A) a component of water-soluble inorganic salt and    (B) a component of at least one lubricating agent selected from molybdenum disulfide and graphite, and    (C) a component of wax    wherein these components are dissolved or dispersed in water, the (B)/(A) solids concentration ratio (as the weight ratio) is 1.0 to 5.0, and the (C)/(A) solids concentration ratio (as the weight ratio) is 0.1 to 1.0.    
     
     
         2 . The waterborne lubricant of  claim 1 , wherein the water-soluble inorganic salt (A) is at least one substance selected from the group consisting of sulfates, silicates, borates, molybdates, and tungstates.  
     
     
         3 . The waterborne lubricant of  claim 1 , wherein the wax (B) is a water-dispersed natural or synthetic wax having a melting point of 70 to 150° C.  
     
     
         4 . The waterborne lubricant of  claim 1  wherein said wax is selected from the group consisting of paraffin waxes, microcrystalline waxes, petrolatum waxes, Fischer-Tropsch waxes, polyethylene waxes, polypropylene waxes, carnauba wax, and montan wax.  
     
     
         5 . A method for forming a lubricating coating, comprising the steps of: 
 a) applying a waterborne lubricant according to any one of claims  1 - 4  to a conversion-coating free metal surface; and    b) drying said lubricant on said metal surface.    
     
     
         6 . The method according to  claim 5 , wherein the waterborne lubricant is applied in an amount that causes the formation of a 0.5-40 g/m 2  lubricating coating after application and drying.  
     
     
         7 . The method according to  claim 5 , further comprising a pre-treating step of shotblasting, sandblasting, alkaline degreasing, and/or pickling the metal surface prior to step a).  
     
     
         8 . The method according to  claim 5 , wherein step a) is performed on the metal surface heated to 60-100° C.  
     
     
         9 . The method according to  claim 5 , wherein the waterborne lubricant applied in step a) has a temperature of 50-90° C.  
     
     
         10 . A nonreactive method for forming a lubricating coating useful in the plastic working of metals on a metal surface comprising: 
 a) applying a waterborne lubricating coating at an add-on of at least 0.5 g/m2 to a conversion coating-free metal surface and    b) drying the waterborne lubricating coating;    said waterborne lubricating coating comprising (A) a component of water-soluble inorganic salt and (B) a component of at least one lubricating agent selected from molybdenum disulfide and graphite, and (C) a component of wax wherein these components are dissolved or dispersed in water, the (B)/(A) solids concentration ratio (as the weight ratio) is 1.0 to 5.0, and the (C)/(A) solids concentration ratio (as the weight ratio) is 0.1 to 1.0.    
     
     
         11 . The method according to  claim 10 , further comprising a pre-treating step of shotblasting, sandblasting, alkaline degreasing, and/or pickling the metal surface prior to step a).  
     
     
         12 . The method according to  claim 10 , wherein step a) is performed on the metal surface heated to 60-100° C.  
     
     
         13 . The method according to  claim 10 , wherein the waterborne lubricant applied in step a) has a temperature of 50-90° C.  
     
     
         14 . A waterborne lubricant useful in the plastic working of metals, comprising: 
 (A) a component of water-soluble inorganic salt;    (B) a component of at least one lubricating agent selected from molybdenum disulfide and graphite, and    (C) a component of wax having a melting point of 70 to 150° C.    wherein these components are dissolved or dispersed in water, the (B)/(A) solids concentration ratio (as the weight ratio) is 1.0 to 5.0, and the (C)/(A) solids concentration ratio (as the weight ratio) is 0.1 to 1.0.    
     
     
         15 . The waterborne lubricant of  claim 14 , wherein the water-soluble inorganic salt (A) is at least one substance selected from the group consisting of sulfates, silicates, borates, molybdates, and tungstates.  
     
     
         16 . The waterborne lubricant of  claim 15  wherein said inorganic salt is selected from the group consisting of sodium sulfate, potassium sulfate, potassium silicate, sodium borate potassium borate, ammonium borate, ammonium molybdate, sodium molybdate, sodium tungstate and mixtures thereof.  
     
     
         17 . The waterborne lubricant of  claim 14 , wherein the at least one lubricating agent is graphite.  
     
     
         18 . The waterborne lubricant of  claim 14 , wherein the at least one lubricating agent is molybdenum disulfide.  
     
     
         19 . The waterborne lubricant of  claim 14  wherein said wax is selected from the group consisting of paraffin waxes, microcrystalline waxes, petrolatum waxes, Fischer-Tropsch waxes, polyethylene waxes, polypropylene waxes, carnauba wax, and montan wax.