SU1291320A1 - Method of oxygen cutting of stacked metal sheets - Google Patents

Abstract

The invention relates to the field of batch sheet cutting. The aim of the invention is to increase the productivity and quality of cutting, reducing stresses and sheet deformations. Prior to package assembly, sheets (L) are glued together in pairs with an epoxy adhesive composition. Then each pair of glued Ls is heated with an acetylene-oxygen flame along the intended cutting line to the working cutting temperature. After that, the pair L is turned over with the heated side down, and in this position, the pairs L are glued together along the cutting line, at certain points outside the heat affected zone of the cut and along the edges. The resulting package is laid between the thick auxiliary L, in the plane of which the through grooves are made along the cutting line through which the cutting is performed. After cutting, the adhesive glue is heated to 300-400 ° C, burn out, and the cut Ls are separated from each other. This reduces the gaps between the A and makes it possible to increase the pressure of the cutting oxygen and the speed of batch cutting. The cutting productivity increases by 23-27%, the oxygen consumption decreases by 10-12%. 1 hp ff. 0. to with SO

Description

The invention relates to the cutting of alloys, mainly to the technology of cutting packages assembled from thin steel sheets.

The purpose of the invention is to improve the quality of the cut, decrease stresses and deformations of the sheets and increase productivity.

The method is carried out as follows.

Before cutting the package, the steel sheets to be cut are glued together in pairs by a thin layer of epoxy composition at individual points of the plane of contact of the sheets outside the heat-affected zone of cutting, then each pair of glued sheets is heated with a gas flame along the proposed cutting line to the working cutting temperature, turned over with a heated top sheet down, after all the pairs of sheets in the specified position are glued along the line of the proposed cut, at certain points outside the heat affected zone of cutting and along the edges of the sheets with epoxy composite position to form a common packet.

The resulting package is placed between the thick upper and lower auxiliary sheets, in the plane of which the through holes are made in the form of a groove with jumpers located along the cut line, with a width of 3 d + 12 mm (where d is the diameter of the cutter mouthpiece) sheets is carried out the cutting process.

After the end of the cutting, the glue seams are heated with an acetylene-oxygen flame to 300-400 ° C, as a result of which the layers of the epoxy compound burn out and the cut sheets are easily separated from each other. At the same time, the own stresses in the cutting area are removed in the sheet metal.

In the proposed method, in addition to heating the sheets from above, the sheets which are connected in pairs are also preheated, then the heated pairs of sheets are turned over, glued together in a package and subjected to cutting. Therefore, the oxidation of the inner heated metal layers is intense and there are no interruptions in the cutting. In addition, this set of operations makes it possible to create preliminary stresses in the metal, opposite in sign and approximately equal in magnitude to the stresses that occur in the metal during the cutting itself, i.e., to significantly reduce the temporary and residual stresses at the edges of the cut, and hence the gaps between the sheets. The latter allows to further increase the pressure of the cutting oxygen, to increase the productivity and quality of cutting. In addition, preheating of the inner sheets of the stack prevents the formation of martensite structure at the cutting edges, which is associated with a local increase in the volume of the metal and the occurrence of significant compressive stresses.

The proposed method also eliminates the need to cut thick auxiliary sheets when cutting each package, which also reduces the initial heat input, the amount of stresses and deformations of the package during cutting, reduces the consumption of acetylene and oxygen, and improves the productivity and quality of cutting.

Example. Batch cutting of mild steel sheets is performed. Sheets with a thickness of 5 mm in an amount of 16 pcs. assembled into a bag with a total thickness of 80 mm in the order appropriate to the proposed technology. To do this, a line is preliminarily marked on the surface of each sheet.

, cutting and places to which the adhesive composition is to be applied.

At first, the sheets are glued together in pairs in separate points of the contact plane outside the heat-affected zone of cutting, and then along the ends of the sheet contour. An epoxy composition consisting of 30% epoxy resin, 5% modifying polyester acrylate resin, 10% dibutyl phthalate (plasticizer), 50% iron powder (filler) and 5% polyethylene polyamine (hardener) is used as an adhesive. When

if necessary, the composition is thinned with a solvent (toluene) or acetone to reduce viscosity and to obtain thin adhesive interlayers. To speed up curing, the sheets are heated at the point of application

Q up to 80-100 ° C. When gluing sheets in pairs, the previously marked sides of the sheets are positioned outside.

After gluing, each pair of sheets is heated from one side along the intended cut line with acetylene-oxygen flame to the working cutting temperature, i.e. 1100-1150 ° C.

In the sheets of the pair, after cooling, longitudinal 0y (x, y) and transverse ax (x, y) residual stresses appear.

In accordance with the flat-stress state scheme, tensile stresses arise at the heating site at a distance of 20-40 mm from the line of the future cut, which in the upper pair of the heating sheet is much larger than in the lower sheet. All eight pairs of sheets are turned over with heated sides down and in this position are glued together with a thin layer of epoxy composition 40–60 mm wide along the line of the intended cut, as well as at certain points outside the heat affected zone of cutting and

0 along the edges of the resulting package.

The bag is then laid between the lower and upper auxiliary sheets of the same steel with a thickness of 20 mm. The auxiliary sheets consist, as it were, of two parts (the framing part and the cutout are cut out), connected by small bridges and provided with a through groove along the cutting line 40 mm wide (with a cutter mouth diameter of 28 mm) and thus in

The cutting process is not cut. The attachment of the auxiliary sheets to the package is not performed and this allows continuous cutting with a small movement of the sheets along the cut contour in the place of the jumpers.

The cutting is done with high pressure oxygen (5-6 kgf / cm) at an average cutting speed of 210 mm / min. The consumption of second-grade oxygen (purity 99.5%) was 11–11.5, acetylene 0.35–0.46.

With a small impact of a heating flame (heating through a thick auxiliary sheet) and a high cutting speed at the edges of the cut and with a small distance from them and the martensitic transformation occurring at this place, compressive stresses usually occur, and for a long distance from the cutting line wives stretch.

In the top sheet of each inverted pair of sheets before cutting, these stresses are larger than in the bottom sheet, due to the greater heat input to the top sheet. Therefore, the preheating of the sheets and the operation of turning the pairs of sheets when gluing the bag provide a significant reduction in the intrinsic stresses and their more uniform distribution after cutting.

In the immediate vicinity of the cutting line, the tensile and compressive stresses are balanced. For this reason, the residual stresses, including at the cutting edges when cutting with the proposed method, are much lower.

As a consequence, the deformation of the sheets after cutting by the proposed method is minimal and significant gaps between the sheets do not occur. This is what allows cutting with high pressure oxygen and increasing the cutting speed up to 200 mm / min or more.

In this case, the cut is obtained with a width of 5-6 mm, without burr and at the level of the first quality class (non-perpendicularity is 1.6-2.0 mm, roughness 0.6-0.8mm).

Immediately after the end of the cutting, the sheets are briefly heated in places where the adhesive composition is applied up to 300-400 ° C with an acetylene-oxygen flame, as a result of which the adhesive layers fade and the sheets of the bag are released one from the other. At the same time, residual stresses due to tempering are reduced.

Claims (2)

1. A batch oxygen cutting method for metal sheets in which the sheets are assembled into a package, a package is placed between the lower and upper auxiliary sheets, cut and detached from each other, characterized in that, in order to increase the productivity and quality of cutting, to reduce stresses and sheet deformations, before assembling the package, the sheets are glued together in pairs with epoxy adhesive composition in separate points of the contact plane outside the heat-affected zone of cutting, heat each pair along the cutting line to the cutting temperature, rachivayut down the heated sheet, after which the pair of sheets are bonded along the cutting line, and at separate points on the edges, and after cutting the remaining packet glue seams are heated to burn off the adhesive composition and removal of residual stress and disconnected from each other sheets. 2. A method according to claim 1, characterized in that through holes are made in the plane of the auxiliary sheets along the cutting line, the width of which is 5 d -f 12 mm, where S - width, d - diameter of the torch mouthpiece. 0 five