METHOD OF PRODUCTION OF TRIBLETS OF PILGRIM-STEP ROLLING MILLS Russian patent published in 2005 - IPC

FIELD: metallurgy; pipe rolling.

SUBSTANCE: the invention is pertaining to the field of pipe rolling, in particular, to the methods of production of triblets of pilgrim-step rolling mills and may be used at production of triblets of pilgrim-step rolling mills for rolling of hot-rolled pipes of large and average diameters (273-550 mm). The method provides for casting of steel ingots, production of triblets out of the steel ingot blanks by, a heat treatment of the triblet ingot blanks, their mechanical working to obtain the finishing dimension with subsequent hardening by a roller run, casting of carbon steel ingots, application by surfacing on the ingot blanks of a heat-resistant and abrasive resistant layer and production of triblets out of the steel ingots by the pilgrim-step rolling, and in the process of operation after appearance of a net flame erosion cracks conduct a triblet multiple remachining till removal of the heat-resistant and abrasive resistant layer, application of a new heat-resistant and abrasive resistant layer by surfacing, machining till the finishing dimension and hardening by a roller running and determination of the thickness of the heat-resistant and abrasive resistant layer from the following equation Δ = A*µ* (l÷D/S*K), where: A - is the minimal thickness of the surfacing layer after the final mechanical working of a triblet and equaled to 10 mm; D - the maximal diameter of the pipes rolled on the given triblet, mm; S - the minimal wall thickness of the pipes rolled on the given triblet, mm; µ - a reduction ratio at rolling of ingots into the hollow triblet blanks and K - a coefficient equal to 0.02. The invention ensures production of triblets of pilgrim-step rolling mills for rolling of hot-rolled pipes of large and average diameters, usage as the basis of the triblet ingot blanks produced out of a carbon steel instead of alloyed steel, increased resistibility of triblets and as a result of it a decreased share of cost of the technological tools in the cost of production of pipes.

EFFECT: the invention ensures production of triblets of pilgrim-step rolling mills for rolling of hot-rolled pipes of large and average diameters, usage of carbon steel in production of triblet ingot blanks, increased resistibility of triblets, decreased share of triblets cost in the cost of the pipes production.

2 cl, 1 tbl