| 摘要 |
PROBLEM TO BE SOLVED: To provide a lubricant composition for cold plastic working which is coated on the surface of a raw pipe without provision of a chemical conversion lubrication treatment, and to provide a method of efficiently fabricating a steel pipe joint excellent in quality using this lubricant. SOLUTION: (1) The lubricant composition for cold plastic working includes 5-50 mass% of a polyethylene powder having an average particle size of 1-100μm and average mol.wt. of≥20,000, 1-20 mass% of a water-soluble vinyl resin not containing an alkali metal or a water-dispersible vinyl resin that is emulsion-polymerized with a nonionic surfactant or/and a protective colloid, and 0.1-5 mass% of a nonionic dispersant. (2) A raw pipe coated on its inside with the lubricant composition and dried is annularly fitted to a bent conic mandrel, and the raw pipe of ordinary temperature is pushed out by a pusher, while expanded by the bent conic mandrel, to form an elbow. COPYRIGHT: (C)2010,JPO&INPIT |
