PIPE MANUFACTURE METHOD Russian patent published in 1996 - IPC

FIELD: plastic working of metals. SUBSTANCE: method involves applying lubricant onto workpiece; drawing and oxygen-free annealing of pipes, with lubricant layer on their surface. Carboxylic acid salt used as lubricant has nitrogen-bearing base selected in the group containing ammonia, ethylenediamine, carbamide, diphenylguanidine. Method allows degreasing process normally used prior to annealing to be excluded, sticking and sooty deposits to be eliminated, roughness of surface to be reduced. EFFECT: increased efficiency of process and improved quality of pipes. 3 tbl