RU2302309C1 - Method for shaping non-equal flange channel section - Google Patents

Abstract

FIELD: plastic working of metals, possibly manufacture of non-equal flange channel sections.

SUBSTANCE: method comprises steps of successively bending from pass to pass edge members of strip blank by predetermined bending radiuses while changing concrete values of bending angles in direction of shaping. In first and second passes bending angle α of small flange of section is set equal to 24 - 25° and in pre-final pass bending angle α is set equal to 10°. Bending angle of large flange in pre-final pass is increased relative to such angle of previous pass by 8 - 9°. Bending radiuses for all passes are constant ones and they are equal to doubled thickness of section.

EFFECT: improved quality of non-equal flange channel sections due to their enhanced geometry and due to lowered manufacturing expenses.

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Description

The invention relates to the processing of metals by pressure and can be used in the manufacture of cold-formed channel profiles.

Such profiles are made by sequentially bending the edge elements of the strip blank in the forming stands of the roll forming mill. In this case, the partial (in one pass) bending angles are first increased, and then (in the finishing and finishing passes) reduced; bending radii are usually successively reduced in the direction of profiling. The technology for forming channel type profiles is described in sufficient detail, for example, in the book of A. P. Chekmarev and V. B. Kaluzhsky “Bent profiles of rolled products”, M., “Metallurgy”, 1974, pp. 104-110.

There is a method of profiling equal-channel channels with different bending radii along the aisles, in which the size of the roll gaps also varies along the aisles depending on the profile parameters and the strength of the strip billet (see US Pat. RF No. 2164186 class B21D 7/00, publ. In BI No. 8, 2001). However, this method is not acceptable for the production of bent non-right channel channels.

The closest analogue to the claimed object is a method for profiling unequal channels according to US Pat. Russian Federation No. 2148452 class B21D 5/06, publ. in BI No. 13, 2000

This method consists in sequentially bending along the aisles of the edge elements of the strip blank with predetermined bending radii and changing the partial bending angles in the profiling direction and is characterized in that the total bending angles along the aisles are taken depending on the widths of both shelves of the profile and the total bending angles in the previous pass and these dependencies are different for different total bending angles of the large and small shelves.

The disadvantage of this method is the possibility of its use only on roll forming mills of a light type (for the classification of mills, see, for example, in the reference book under the editorship of I. S. Trishevsky “Production and use of bent sections of rolled products”, M., “Metallurgy”, 1975, .131-132, table 16. The use of the above method on mills of a more "heavy" type (for example, 2 ÷ 8 × 100 ÷ 600) does not guarantee the receipt of profiles with the required geometry due to the possibility of increased longitudinal twisting, which requires additional editing finished channels .

The technical task of the invention is to improve the quality of unequal channel profiles by improving their geometry and reducing production costs.

To solve this problem, in the molding method, which consists in sequentially bending the edge elements of the strip billet with predetermined bending radii and changing the partial bending angles in the profiling direction, in the first and second passes, the bending angle α of the small profile shelf is taken to be 24 ° ... 25 ° and in the pre-passage passage α = 10 °, and the bending angle of the large shelf in this passage is increased compared to the previous passage by 8 ° ... 9 °, while the bending radii in all passes are assumed to be constant and equal to double thickness rofilya.

The above profiling parameters are obtained as a result of experiments and are empirical.

The essence of the proposed technical solution consists, firstly, in optimizing the bending angles of a strip billet in specific passes in terms of reducing longitudinal twisting of profiles and, secondly, in adopting equal bending radii in all passes, which simplifies and reduces the cost of manufacturing tools (rolls). As a result of this, the quality of unequal channel sections is improved and the cost of their production is reduced.

This method is implemented by using forming rolls in the specific stands of the roll forming mill with the appropriate gauge configuration and with defined mating radii of the lateral (conical) and horizontal elements of the upper rolls. At the same time, for the production of high-quality unequal channel profiles, only six forming passes are required (versus 9 ... 10 commonly used), which reduces roll consumption with a corresponding reduction in costs.

Experimental verification of the proposed method was carried out on a high-quality roll-forming mill 1 ÷ 4 × 50 ÷ 300 OJSC "Magnitogorsk Iron and Steel Works".

For this purpose, when forming the channel profile 135 × 85 × 50 × 3 mm from steel grade 09G2S, containing a small vertical shelf with a width of 50 mm and a large shelf with a width of 85 mm, inclined at an angle of 60 ° to the horizontal, the bending angles along the aisles and the radii were varied bending.

The best results (yield of high-quality profiles in the range of 99.5 ... 99.8%), as well as the minimum roll consumption, were obtained when implementing the recommended technology. Deviations from the claimed profiling parameters worsened the achieved indicators.

Thus, a decrease in the partial bending angle of the small profile shelf in the first two passes to 12 ° ... 15 ° (the partial angle is the bending angle in this passage; it is the difference between the total bending angles in this and the previous pass) increased by 2 ... 3 number of forming stands. A decrease in the bending angle of a small shelf (to 7 ° ... 9 °) and a large (by 1 ° ... 3 °) in the pre-finish passage led to the appearance of unacceptable longitudinal twisting of the profiles, and an increase in the angles, respectively, to 11 ° ... 13 ° and by 10 ° ... 12 ° caused cracking of bending places on individual rods.

The use of various (along the aisles, with a decrease along the profiling) bending radii did not affect the improvement of the geometry of the profiles, but led to an increase in labor costs by 15 ... 20%. The use of the same bending radii in all the passages, but more than a double profile thickness, increased the end defects of the profiles (“dump” and “camber”) and reduced their stiffness. With the same bending radii, but less than 6 mm, cracks were noted.

Control profiling according to the technology taken as the closest analogue (see above), reduced the quality level of channels to 67 ... 72%, and the number required for molding stands increased to 9.

Thus, the experiments confirmed the acceptability of the claimed technical solution to achieve the goal and its advantages over the known object.

According to technical and economic studies conducted at OJSC MMK, the use of the proposed technology in the production of bent unequal channel sections at the plant will increase the yield of high-quality rolled products by at least 99.5 ° and reduce production costs by an average of 17%.

Concrete example

The non-equal-channel channel profile 135 × 85 × 50 × 3 mm from 09G2S steel, having a small vertical shelf with a width of 50 mm and a large shelf with a width of 85 mm, inclined at a horizontal angle of 60 °, is formed in seven passes.

Bending angles along the aisles (α - small shelf, β - large), degrees:

α = 0 ° → 25 ° → 25 ° → 15 ° → 12 ° → 10 ° → 3 °;

β = 0 ° → 14 ° → 13 ° → 7 ° → 6 ° → 15 ° → 5 °,

those. the bending angle of the small shelf in the pre-passage passage is α = 10 °, and the large - β = 15 ° (more than in the previous passage, by: 15 ° -6 ° = 9 °).

The bending radii in all the passages are the same and equal to a double profile thickness of 6 mm.

Claims (1)

A method of forming an unequal channel channel profile, comprising bending sequentially along the aisles of the edge elements of the strip blank with predetermined bending radii and changing the partial bending angles in the profiling direction, characterized in that in the first and second passes, the bending angle α of the small profile shelf is taken equal to 24-25 ° , in the pre-passage passage α = 10 °, and the bending angle of the large shelf in the pre-passage passage is increased compared to the previous passage by 8–9 °, while the bending radii in all passes are taken at a constant GOVERNMENTAL and equal to twice the thickness profile.