| 摘要 |
PROBLEM TO BE SOLVED: To obtain a lubricating oil which shows excellent lubricating properties when used in the drawing of steel pipes and remains little on the inside surface of the drawn steel pipe to be annealed by using a specified polyoxypropylene glycol ether. SOLUTION: This oil contains a polyoxypropylene glycol ether represented by formula I [wherein R is Cn H2n+1 or Cn H2n-1 (wherein n is 12-18)] and having an average molecular weight of 2,400-3,000. Alternatively, it contains a polyoxypropylene glycol ether represented by formula I and having an average molecular weight of 1,800-3,000 and 10-70wt.% at least one member selected among fatty acid esters represented by the formula: R1 COOR2 [wherein R1 is Cm H2m+1 or Cm H2m-1 (wherein m is 11-17); and R2 is Cn H2n+1 (wherein is 1-4)], neopentyl glycol esters (wherein the number of carbon atoms of the fatty acid to be esterified is 6-12) represented by formula II, trimethylolpropane esters (wherein the number of carbon atoms of the fatty acid to be esterified is 6-12) represented by formula III, and pentaerythritol esters (wherein the number of carbon atoms of the fatty acid to be esterified is 6-12) represented by formula IV. |
