RU2342208C2 - Method for production of cold-formed sections of closed type - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: initial blank is serially deformed in several stages by rolling tool of roll-forming machine with shaping of preset profile. At first shelf is bent on two sides of strip with width that is equal to half of top part of profile at the angle of 90°, in subsequent stages side walls are bent, then profile bottom is deformed upwards in the last but one stage. In the last stage it is straightened by extrusion with technological tool that is rigidly fixed in roll-forming machine.

EFFECT: higher quality of output produce and reduction of expenses.

Description

The invention relates to the processing of metals by pressure, in particular to the production of cold-formed sections of a closed type.

The wide range of applications of bent sections of rolled products in construction, agricultural engineering, the automotive industry, etc. is mainly due to the possibility of producing high-performance profiles of virtually any configuration in cross section, various sizes in width, thickness and length of sheet and strip steel, non-ferrous metals and alloys , high quality of the surface of the profile, as well as the ability to obtain the dimensions of the profiles in a high accuracy class. Bent profiles of hire are in many cases finished parts or products that do not require further processing.

By rolling it is possible to obtain profiles from preforms with a pretreated surface or coating. Bent profiles made of galvanized metal are highly resistant to corrosion and are widely used in the construction of buildings and structures.

Known methods for the production of bent profiles from strip metal by cold forming (bending) between the rollers, using equipment to prepare the original strip for profiling (unwinder, scissors for cutting into measured strips) and equipment for removing and packaging finished profiles. The gradual bending of the strip into the desired profile is carried out by several successively arranged pairs of rolls (rollers), while the number of pairs of rolls depends on the complexity of the profile and the selected profiling technology. Work rolls are made integral or type-setting (composite) - the necessary profile is recruited from several shaped rolls. Non-driven vertical rollers are installed between adjacent horizontal pairs of rolls, which serve to hold the formed strip in a strictly defined position or to additionally bend the strip, which is especially necessary in the manufacture of closed profiles.

Known methods for the production of cold-formed strip metal profiles are carried out on roll forming mills, profile manufacturing lines and other installations (see invention patents No. 2148454, 2148455 with priority dated February 16, 1999, issued to Ulyanovsk State Technical University, invention patent No. 2257273 with a priority of 04/30/2004, issued by CJSC Arkada, Smolensk, patent for invention No. 2151660 with a priority of 12/28/1998, issued to the Cherepovets Steel Rolling Plant, etc.).

There is a method of profiling equal-channel channels, according to which the successive bending of the strip billet elements is carried out by rolls with different bending radii along the aisles installed with predetermined horizontal gaps. In the first pass, the workpiece is passed through rolls with one gap, in the second pass with a different gap, and in subsequent passes with a constant gap, determined by known dependencies from the conditions for ensuring optimal profiling modes, which simplifies the introduction of the workpiece into calibers and eliminates crack formation (see patent for invention No. 2164186 with priority dated 05/14/1999).

There is also a known method of manufacturing symmetrical profiles by successive bending of profile elements in rolls of a roll forming mill with additional folding of shelves in the inter-stand space by 3-4 °, according to which at the first transition in the middle part of the bent shelf a removable rift is formed by convexity outward with constant mating radii, the second transition is the folding of the shelves with straightening of the rift, and in the interstand space between at least two of the following transitions simultaneously with additional Yelnia podgibkoy shelves produce its transverse bending outwardly convex and subsequent straightening in the next transition in the closed roller caliber, and the height eliminates rift determined by the known formula (see. patent №2222402 with priority from 08.01.2002 g).

A common disadvantage of these methods of profiling is that these methods solve particular problems of the technological process and do not provide for obtaining closed-type profiles.

A known method of obtaining closed profiles, described in the book Chekmareva A.P., Kaluzhsky VB "Bent profiles of hire", Moscow, publishing house "Metallurgy", 1974

According to the indicated method, a calibration system is used for the manufacture of closed rectangular or square profiles, in which at first the closing shelves are formed up to an angle of 80-85 °, then the side walls, while free bending occurs in the main part of the formation of the bending places at the lower horizontal profile wall without upper roll, fixing the place of bending.

The disadvantages of this method are the deflection of the side walls, the gap between the adjoining shelves, as well as the difference in the values of the bending radii at the lower horizontal wall and at the upper adjoining shelves of the finished profile - the lower horizontal wall of the profile has a greater bending radius than that of the adjoining shelves due to various conditions shaping (bending).

A known method of manufacturing bent box-shaped profiles, including sequential bending of the closing and side shelves of the profile in roughing, intermediate and finishing passes and partial unbending of the side shelves in the finishing passage to an angle of 90 °, while when forming the profile from a strip billet with a thickness of 5-8 mm, the angle increment the folds of the closing shelves in the rough passages are made equal to 15 ° with their release from contact with the tool in two intermediate passages and upon reaching an angle of 70-72 ° between the closing and side shelves they bend the first of them at an angle of 0.5 °, and the maximum increment of the bending angles of the side shelves is equal to 20 °, while in the first finishing process, they bend by 2-3 °, followed by bending, starting from the second finishing passage (see the patent for the invention of the Russian Federation No. 2103088 with a priority of August 26, 1996).

The specified technical solution as the closest analogue can be taken as a prototype.

The disadvantages of the prototype are the impossibility of obtaining a complete closure of the shelves (without a gap) and the difference in the magnitude of the bending radii at the lower horizontal wall and at the closing shelves.

The problem to which the present invention is directed, is the manufacture of closed profiles without clearance of the shelving, as well as reducing the internal bending radii to a minimum.

According to the technical solution proposed in the framework of this application for the invention, the task is solved by a new sequence and a new mode of performing profiling operations.

The manufacturing process of cold-formed profiles of closed-type rolled products is as follows. The source material is sheet metal, previously cut into strips of a given width and rolled up into a roll, introduced into the receiving rolls of the roll forming mill and using rolls located in the technological sequence along the strip, bend its sections by a given angle according to the following calibration system: at the first transition, a shelf with a width equal to half the upper part of the profile is bent at 90 ° on both sides of the strip, lateral walls are bent at subsequent transitions, then the bottom is deformed at the next to last transition Profile up and at the last transition straighten it by the extrusion process tool is rigidly fixed to the profile-mill.

Performing operations of the process of profiling a metal strip in the proposed sequence with deformation of the bottom of the profile at the penultimate transition and its subsequent straightening at the final stage of bending allows you to close the shelves of the upper part of the profile without a gap (even with some interference that does not allow them to be unclenched). In addition, due to the bending of the shelves and side walls on the rolls under the action of predetermined forces (i.e., there is no free bending), all internal profile angles are the same, which is one of the important quality characteristics of the finished product.

In the proposed method for manufacturing cold-formed closed-type rolled sections, the selected calibration system (roll configuration, location, interaction with other elements of the roll forming mill, etc.) allows to reduce the number of transitions, reduce the energy consumption of the process and labor costs.

This method is the basis for the production of a wide range of bent profiles of a closed type used in construction, engineering and other industries, and will improve the quality of products and reduce costs.

Claims (1)

A method of manufacturing cold-formed closed-type rolled profiles, including sequential deformation of the flexible initial strip billet into several transitions with a roll tool of a roll forming mill with the formation of a given profile, characterized in that at the first transition from two sides of the strip, the shelf is bent by a width equal to half the upper part of the profile, by an angle 90 °, at subsequent transitions, the side walls are bent, and the shelves and side walls are bent on the rolls with predetermined forces, then in the penultimate transition, the bottom of the profile is deformed upward, and at the last transition, it is straightened by extrusion with a technological tool rigidly fixed to the profile bending mill.