| 摘要 |
<p>Disclosed is a method for the cold-drawing of a metal pipe, which comprises filling a high-pressure container having a base pipe inserted thereinto with a lubricant oil, increasing the pressure of the lubricant oil by means of a pressure-increasing machine, and drawing the base pipe while lubricating the inner and outer surfaces of the base pipe forcibly, wherein a lubricant oil having a kinematic viscosity of 100 to 2000 mm2/s at 40°C and under ambient pressure and a viscosity-pressure coefficient of 15 to 24 GPa-1 at 40°C is used as the lubricant oil, thereby preventing the burning or vibration which usually occurs during the drawing of the base pipe and also preventing the decrease in roughness degree of the inner surface of the finished metal pipe which is usually caused by the generation of oil pits. In the method, it is preferred that the lubricant oil to be used contains one or more extreme pressure additives independently selected from a sulfur-containing extreme pressure additive, a chlorine-containing extreme pressure additive, an organic calcium metal salt, a phosphorus-containing extreme pressure additive, an organic zinc-containing extreme pressure additive and an organic molybdenum-containing extreme pressure additive each containing a specific component in the total amount of 10 mass% or more.</p> |
