Strip steel lengthwise uncoiling method

FIELD: finish working of rolled sheets, possibly lengthwise uncoiling coiled strips for producing narrow strips.

SUBSTANCE: method comprises steps of drawing metal through disc shears at preliminarily notching it; notching strip in shears by depth A due to shifting portions of strip adjacent along strip width in vertical plane in mutually opposite directions; then additionally passing strip through pair of horizontal cylindrical rollers while shifting each of said portions in the same plane but in direction opposite to shifting direction of said portion drawn through shears in order to produce narrow strips. Depth value where h - strip thickness, mm; σy -limit yield of steel, Mpa.

EFFECT: improved quality of ready strip blank for shaping.

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The invention relates to the decoration sheet (strip) rental and can be used for longitudinal dissolution of the slit strips to produce narrow bands.

Such strip of given width can be used as a billet for subsequent profiling, i.e. the manufacture of cold-formed profiles of rent.

Longitudinal dissolution is carried out on the units slitting (APR) using shears. Technology longitudinal slitting hot - and cold-rolled strip steel is described, for example, in the book Have "Design and calculation machines and mechanisms for rolling mills", M, "metallurgy", 1985, s-241.

A method of obtaining a strip of material, in which the cutting edges of the bands of their sensitivity to the cylindrical surface of the knife shears by means of a tapered roller (see A.S. USSR №1368112, CL 23D 19/04, publ. in BI No. 3, 1983). However, this method is unsuitable for cutting the rolled strips on a narrow strip of given width.

The closest analogue to the claimed technology is a method of trimming the edges of the rolled plate shears, as the USSR №517414, CL 23D 19/04, publ. 15.07.76,

This method involves drawing the metal through a disc scissors with its preliminary notching and is characterized by the fact that the cut edges are crushed without a full crop, and satanasword their final trimming.

The known method also unacceptable to produce narrow bands of a wide strip steel, as they will not provide the desired quality.

Indeed, if you cut the metal to a certain depth disk scissors, and then make its final cutting knives, inevitably, the occurrence of burrs on the side edges of the finished strips, which will be greater than the "softer" metal, i.e. less than its strength characteristics and, in particular, the value of the yield strength bt. The appearance of Burr due to the influence of the counter-directed vertical forces from the circular knives, which, in the presence of axial (lateral) of the gap between adjacent knives, leads to the stretching of the metal in the gap.

The technical task of the invention is to improve the quality of strip blanks for profiling by preventing the occurrence of burrs on the side edges of the narrow strips after the dissolution.

To solve this problem in the way that the longitudinal dissolution of the steel strip, comprising drawing the metal through a disc scissors with its preliminary notching,where h is the strip thickness, mm, btthe steel yield strength, MPa, by shifting the adjacent strip width sections in a vertical plane in opposite directions, and then paleodepositional passed through a pair of horizontal cylindrical rollers, shifting each of the said sections in the same plane, but in the direction opposite to the offset area when drawing with a scissors, obtaining narrow strips.

The mathematical dependence obtained by processing the experimental data (see below) and an empirical one.

The essence of the proposed technical solution is to prevent the occurrence of burrs on the side edges of the received narrow bands (presence of burrs on the workpiece profiling greatly accelerates the wear of the forming rolls), as when skipping pre-cut to a certain depth of the strip through the horizontal rollers rupture of the bridges between separate areas on its width and separation of metal in narrow strips.

The inventive method is implemented as follows.

Before longitudinal dissolution of strip knives shears are set so that between the upper and lower knives was vertical gap, providing the incising the metal to the desired value of "Δ". After passing the strip through a disc scissors she enters the gap between the secondary driven horizontal rollers, the value of which is equal to the actual thickness "h" of the band. As a result of this separation is carried out incised metal.

Experimental verification of the proposed method is implemented on APR sheet-rolling shop №7 OJSC "Magnitogorsk iron and steel works" when receiving blanks for profiling on units of the same shop.

To this end, the longitudinal dissolution hot rolled and cold rolled strips of different thickness (h=2...8 mm) steel with bt=350...540 MPa was carried out by pre-notching of metal at different depths, and then it was passed through a pair of horizontal cylindrical rollers mounted for rotary shear APR. Obtained in this method of procurement was profiled on forming section mill, fixing the degree of wear of the work rolls of these mills.

The best results (no burrs on the profiled strips and minimum wear of the rolls) obtained during the implementation of the proposed methods. When the variance value of the cut metal from the optimal (corresponding to the values "Δ" the above dependencies) cut quality was getting worse.

So, whenin some cases, there was no separation of metal on a narrow strip, which has led to the need to stop APR, cutting out the defective areas of the strip and the reconfiguration of shears. At valuesthe metal part was divided into narrow strips with a Burr on the side edges, profiling, which increased the wear of the rolls (1.1...1.6 times greater than the recommended values "Δ").

The method selected as the closest analogue in the experiments were not tested due to its n the eligibility of the workpiece, used when profiling.

Thus, experimental validation confirmed the acceptability found technical solutions to achieve these objectives and advantages over known technology.

According to feasibility studies conducted in the Central laboratory of control of OJSC MMK, using technology developed longitudinal slitting of steel coils with the aim of obtaining a strip of blanks intended for profiling reduces the wear of the forming rolls, on average, 1.4 times, through the use of blanks without burrs on its lateral edges.

Specific example

Preparation for profiling receive the claimed technology from rolled steel strip of thickness h=5 mm, bt=450 MPa.

The value of pre-narezki metal disk scissors APR:

After missing a cut strip through a pair of horizontal rollers narrow strips do not have burrs on the edges.

Method longitudinal slitting strip steel, mostly blanks for profiling, including feeding the strip through the disk scissors with its preliminary notching and receiving narrow strips, characterized in that the strip is cut in the cutting depth

,

where h is the strip thickness, mm, σtthe steel yield strength, MPa,

offset adjacent strip width sections in a vertical plane in opposite directions, and then further passed through a pair of horizontal cylindrical rollers offset of each of the said sections in the same plane and in the direction opposite to the offset of the plot when drawn through the scissors.



 

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FIELD: finish working of rolled sheets, possibly lengthwise uncoiling coiled strips for producing narrow strips.

SUBSTANCE: method comprises steps of drawing metal through disc shears at preliminarily notching it; notching strip in shears by depth A due to shifting portions of strip adjacent along strip width in vertical plane in mutually opposite directions; then additionally passing strip through pair of horizontal cylindrical rollers while shifting each of said portions in the same plane but in direction opposite to shifting direction of said portion drawn through shears in order to produce narrow strips. Depth value where h - strip thickness, mm; σy -limit yield of steel, Mpa.

EFFECT: improved quality of ready strip blank for shaping.

1 ex

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