Technique for producing rod iron with large diameter for mechanical manufacture

Abstract

The invention relates to a coil rod production process, in particular to a production process of a major-diameter coil rod for machine manufacturing. The heating time lasts 2.25 hours to 3 hours, and the heating speed ranges from 9 min / cm to 12 min / cm during the heating of a steel billet; the inlet temperature of a No. 0 rolling mill is controlled within the scope ranging from 950 DEG C to 1000 DEG C in a rough rolling procedure; the outlet temperature of a No. 11 rolling mill is controlled within the scope ranging from 1000 DEG C to 1050 DEG C in the medium rolling procedure; the outlet temperature of a No. 13 rolling mill is controlled within the scope ranging from 1050 DEG C to 1100 DEG C in the pre-finish rolling procedure; before the CCR rolling procedure, a rolled piece is led out from the pre-finish rolling procedure and enters a CCR rolling machine after being cooled in No. 4 and No. 5 water tanks, and the inlet temperature of the rolled piece in the CCR rolling machine is lower than 850 DEG C; before the coiling procedure, the rolled piece is cooled in a No. 6 rolling machine after exiting the CCR machine, and the temperature of the rolled piece is lower than 800 DEG C. The major-diameter coil rod for the machine manufacturing can obtain the major-diameter coil rod which has mechanical properties of excellent organization and deep processing, has the advantages of no surface scratch and complete rolling shape and is used for machine manufacturing.

Description

technical field [0001] The invention belongs to the field of metallurgy and relates to a production process of a wire rod, in particular to a production process of a large-diameter wire rod for mechanical manufacturing. Background technique [0002] Large-diameter wire rod production line has two modes: single-line and compound line. The investment cost of single-line rolling is relatively large, and compound line rolling can share the heating furnace, rough and medium rolling unit, pre-finishing rolling unit and finishing PF transportation line, and the investment cost is reduced. , but after the rolling line is separated, some new problems will arise. On the one hand, the corners are easy to scratch the surface of the finished product. In addition, a new type of water cooling box with sufficient cooling capacity is required to ensure low-temperature final rolling and low-temperature coiling. [0003] As a large-diameter wire rod for machinery manufacturing, its hot-rolled ...

AI Technical Summary

Problems solved by technology

One problem is that in order to prevent uneven cooling of the rolled piece from causing fluctuations in the performance of the same ring, the grain growth rate after rolling in the recrystallization temperature zone is accelerated to make the grain rough; the other problem is that in the non-recrystallization temperature zone During the period from the end to the beginning of the accelerated cooling process, the thermal effect of rolling still exists, so the rolling effect in the non-recrystallization temperature region cannot be fully utilized