Development of cold-rolled cold drawn tubes production process and modification procedures

Configuring cold manner by cold rolling and cold drawn usage mode configuration with a single cold-rolled, cold-drawn and cold-rolled cold drawn single combined three kinds of programs.

(1) single cold rolling plan. And cold drawn compared to cold rolling when the stress state is good, large deformation passes, can reduce intermediate processes and shorten the production cycle, to reduce consumption and lower costs, suitable for processing high plasticity poor difficult deformation of steel pipe and non-ferrous metals. The disadvantage is low productivity, production flexibility is small.
(2) a combination of cold-rolled cold-drawing program. Are reasonable program of pipe cold, cold to play a combination of cold drawn large cold rolling and cold drawing production flexibility advantage to reduce the process and shorten the production cycle, increase productivity and expand varieties of cold-rolled cold drawn when combined program, usually on the first pipe material cold mill to a pass fixed wall or fixed wall before, and then pull the system, until the finished product passes.
(3) A single cold drawing program. Since the pass deformation cold drawn smaller, deformation passes more intermediate steps, long production cycle, metals and auxiliary materials consumption, the single cold drawing program is not the optimal solution. But Stubbs the machine structure than the cold rolling mill is simple, low investment, easy to master the operation, ease of manufacture and replacement tools, production flexibility, productivity is high. Therefore, a single program to process cold drawn carbon steel, low alloy steel pipe and general colored metal pipe is widely used in the actual production.

In the cold pipe production, the tubing size (diameter and thickness) determines the deformation passes, finished pipe dimensional accuracy and surface quality. In the finished tube to ensure the quality of the premise of choice nearly finished size of pipe material as possible. Pipe The minimum wall thickness of the material should be able to ensure that the finished pipe wall thickness of the pipe material and the difference between (ie the total amount minus the wall) to eliminate hot-rolled tubes threaded surface road, designated road and other surface defects, improve uneven wall thickness, in order to obtain dimensional tolerances and surface quality are in line with the requirements of the pipe in the drawn tube production, the minimum total amount minus the wall of cold drawing generally take 0.5 ~ 1mm. of finished pipe quality (dimensional accuracy, surface quality) to be high when the total reduction wall larger amount of In may supply conditions, pipe material diameter is generally larger in diameter than the finished tube 5 ~ 20mm. mainly on account of reducing the amount of wall-volume relationship, Tianjin Seamless Steel Tube Plant, there is a certain time that is deformed reduced wall must have the appropriate amount of reducing the amount in order to ensure the smooth realization of metal deformation, desulfurization pump mechanical seal.

Pass deformation choice of determining the degree of deformation (compression section, extension coefficient) for each processing passes, reducing the amount of volume and reduce the wall. When conditions permit, should choose a large amount of deformation passes to reduce processing To consider the strength of the main components of the mill, when the plastic material passes. Choose cold rolling mill road deformation amount times the pipe's quality requirements. In the actual production tubing dimensional accuracy, surface condition and life of the tool so often be the limiting road Factors times the amount of deformation. In order to ensure the yield and quality, the deformation of the finished product passes should take a small number in the multi-roll cold rolling mill deformation amount of time on the road (especially reducing the amount) than the two-roll cold rolling mill . The small amount of deformation of selection factors passes drawing machine are: cold working properties of metals (including metal strength and ductility), the tube body strength (can not pull off the system when you pull phenomenon), pulling machines capabilities and optional drawing styles (see cold-rolled cold drawn pipe) and mold type (see drawing of the tool) into consideration when selecting pull system track the amount of deformation times should be considered are: pull even passes (passes in the middle without heat treatment) how much, heat treatment, pickling, lubrication quality is good or bad deformation pass determined as: wherein the total elongation factor pipe material processing to finished grounds; F0 as tubing cross-sectional area; Fk for the finished pipe cross-sectional area; mc is the average extension coefficient. When combined with pulling rolling program uses, can be set in accordance with the specific conditions of cold-rolled and cold drawn pipe machine configuration and the existing cold rolling mill pass system, is determined by the cold-turn when cold drawn intermediate pipe size, and then calculate the cold rolling and cold drawing passes, their sum is the total deformation passes.