Cold Working Lubricant and Cold Working Method for Steel Pipe

Abstract

The present invention provides a lubricant comprising an alkali soap and a cold working method, in which the lubricant layer can be easily formed on the surface of a steel pipe prior to cold working the reduces the work load during cold working of the steel pipe, and whose layer can be easily removed by washing the surface of the steel pipe after cold working. After that, an alkali soap aqueous solution or aqueous pasty alkali soap is applied to the working surface of the steel pipe, cold working of the steel pipe is performed, and thereafter the alkali soap layer is removed by washing with water. The alkali soap aqueous solution or aqueous pasty alkali soap is preferably prepared within a vessel having an inner surface consisting of a non-metal material.

1 . A cold working method for a steel pipe, comprising cold working after forming a solid alkali soap layer on the working surface of a steel pipe by coating an alkali soap aqueous solution thereto. 
   
   
       2 . A cold working method for a steel pipe, comprising cold working after forming a solid alkali soap layer on the working surface of a steel pipe by coating an alkali soap aqueous solution thereto followed by drying. 
   
   
       3 . The cold working method for a steel pipe according to  claim 1 , wherein the alkali soap aqueous solution to be coated to the working surface of the steel pipe is prepared by dissolving alkali soap in water within a vessel having an inner surface consisting of a non-metal material. 
   
   
       4 . The cold working method for a steel pipe according to  claim 2 , wherein the alkali soap aqueous solution to be coated to the working surface of the steel pipe is prepared by dissolving alkali soap in water within a vessel having an inner surface consisting of a non-metal material. 
   
   
       5 . A cold working method for a steel pipe, comprising cold working after forming a solid alkali soap layer on the working surface of a steel pipe by coating an aqueous pasty alkali soap thereto. 
   
   
       6 . A cold working method for steel pipe, comprising cold working after forming a solid alkali soap layer on a working surface of a steel pipe by coating an aqueous pasty alkali soap thereto followed by drying. 
   
   
       7 . The cold working method for a steel pipe according to  claim 5 , wherein the aqueous pasty alkali soap to be coated to the working surface of the steel pipe is prepared by impregnating alkali soap with water within a vessel having an inner surface consisting of a non-metal material. 
   
   
       8 . The cold working method for a steel pipe according to  claim 6 , wherein the aqueous pasty alkali soap to be coated to the working surface of the steel pipe is prepared by impregnating alkali soap with water within a vessel having an inner surface consisting of a non-metal material. 
   
   
       9 . The cold working method for a steel pipe according to any one of  claims 1  to  8 , wherein the cold working of the steel pipe is a pipe expansion work of the steel pipe end using a plug. 
   
   
       10 . The cold working method for a steel pipe according to any one of  claims 1  to  8 , wherein the alkali soap is composed of either or both of Na salt and K salt of one or more kinds of straight-chain fatty acids having 10 to 18 carbon atoms. 
   
   
       11 . The cold working method for a steel pipe according to any one of  claims 1  to  8 , wherein the cold working of the steel pipe is a pipe expansion work of the steel pipe end using a plug, and wherein the alkali soap is composed of either or both of Na salt and K salt of one or more kinds of straight-chain fatty acids having 10 to 18 carbon atoms.