RU2060064C1 - Method of making thin-wall plates with corrugated portions - Google Patents

Abstract

FIELD: production of thin-wall corrugated plates for heat exchangers of systems of heat regeneration of gas-turbine engines. SUBSTANCE: method of making thin-wall plates with corrugated portions, surrounded along their perimeter by flat areas, comprises one-stage process, including a lengthwise rolling of a belt by two rolls, had been sized for making corrugations on respective portions of a blank, according to condition h_cor=(b_cor•h_init)/(l_cor•λ_cor).. One of the rolls has flat portions along its lengthwise axis, having a width Ln. These portions are being flush relative to a base of a grooved pass and spaced one from another by a distance L, corresponding to a length of the corrugation. A diameter of the rolls is being selected according to condition D=n(L+Ln)/π. A gap between the rolls on the flat portions along edges of barrels is being set equal to h_edgc=(l_cor•h_cor)/b_cor=h_init/λ_cor,, where h_init - a thickness of an initial belt; b_cor- a width of the corrugated portion; h_cor - a thickness of a wall of the corrugation, l_cor - a length of a development of the corrugated portion in a cross direction to a plane; λ_cor - a factor of metal elongation on the corrugated portion in longitudinal directional n - a number of the corrugated portions along a perimeter of the roll barrel. EFFECT: enhanced efficiency of the method due to lowered number of operations. 1 cl, 5 dwg, 1 tbl

Description

 The invention relates to the field of production of thin-walled corrugated plates for heat exchangers of heat recovery systems of gas turbine engines (GTE) and can be used in motor-engineering enterprises producing gas turbine engines for aviation, water and land transport.

 In world practice, the trend is the use of heat exchangers for heat recovery systems of gas turbine engines, the main working element of which is a set of thin-walled corrugated plates of many thousands. Such plates are made of stainless steel 0.18-0.2 mm thick with corrugations about 1.5-2.0 mm high and with a corrugation pitch of 2.0-3.0 mm. Thus, on the basis of 100 mm, the number of corrugations can reach 50 pieces. Moreover, corrugated sections on the finished plate are surrounded by flat sections along the perimeter.

 A known method of producing corrugated products from sheet blanks by molding (bending) on roll forming mills. However, for the manufacture of plates with corrugated sections surrounded by flat sections around the perimeter, this method is not applicable, since it is designed only for cases where the corrugations are through, that is, there are no transverse flat jumpers.

 Closest to the proposed method according to the achieved result is the manufacturing technology of thin-walled corrugated plates described in the work. The essence of this technology is as follows. First, a flat plate of predetermined dimensions is cut out of the tape on the stamp. Then, after heat treatment and lubrication, the workpiece is installed in the stamp and the 1st transition is carried out, i.e., an incomplete corrugation is stamped. After that, the workpiece is removed from the stamp and subjected to heat treatment. The following operations are repeated 4-5 times until a complete corrugation profile is obtained.

The specified technology has the following disadvantages:
multioperation and low productivity;
the use of manual labor and the inability to create in-line production;
a large number of intermediate heat treatments;
high cost of production.

 The purpose of the invention is the creation of mechanized in-line production of plates, an increase in productivity several times, the exclusion of intermediate heat treatments, a significant reduction in the cost of products.

 In FIG. 1 shows the arrangement of corrugated sections surrounded by perimeter flat sections; in FIG. 2 calibration of the rolls to obtain a plate with corrugated sections; in FIG. 3 arrangement of calibers to obtain a plate with corrugated sections; in FIG. 4 example of the implementation of the proposed manufacturing method with specific dimensions; in FIG. 5, section AA in FIG. 4.

The manufacturing process of thin-walled plates with corrugated sections (Fig. 1) is carried out at one time in the mode of deformation of the tape by longitudinal rolling in two rolls. As a result, a tape is obtained with corrugated sections of length L and width b _g , separated by flat transverse sections of a given size L _p . Thus, the corrugated sections are surrounded by perimeter flat sections.

To obtain corrugations of the required shape and size, calibers are cut on the rolls (Fig. 2). When rolling, in addition to deformation along the thickness of the tape in gauges, the tape is deformed in the direction of its length (hood). Therefore, based on the law of constancy of the volume of metal, calibration is performed from the condition
h _g = (b _g · h _o ) / (l _g · λ _g ), where h _g wall thickness of the corrugation;
b _{g the} width of the corrugated area;
h _{o the} initial thickness of the tape;
l _{g the} length of the scan corrugated section in the transverse direction to the plane;
λ _g - the coefficient of metal drawing in the corrugated section in the longitudinal direction.

Since the elongation (drawing) of the metal occurs on the corrugated section, a corresponding elongation of the flat sections along the edges of the tape is necessary to maintain flatness. To do this, the gap between the rolls on smooth sections along the edges of the barrels (Fig. 2) is set equal to:
h _k = h _o / λ _g = (l _g · h _g ) / b _g .

In order to obtain transverse flat sections on the tape on one of the rolls along its longitudinal axis, smooth sections of width L _{n are made} flush with the base of the calibers at a distance from each other L corresponding to the length of the corrugated section (Fig. 3). From the condition of the location on this roll multiple of corrugated and flat sections, its diameter is prescribed by the ratio;
D n (L + L _p ) / π, where n is the number of corrugated and, accordingly, flat sections along the perimeter of the roll barrel.

 When the above conditions are met, through the high-performance process of longitudinal rolling at a speed of several meters per second, the production of thin-walled plates with corrugated sections surrounded by flat sections around the perimeter is ensured, while maintaining the flatness of the tape. Directly in the mill line or after heat treatment in continuous furnaces, it is possible to cut the tape using drum scissors into separate plates to carry out subsequent operations with them, provided for by the technology for the manufacture of gas turbine heat exchangers.

 Thus, the proposed technical solution meets the criterion of "inventive step", because it provides results that are not provided for by the known technical solutions.

 PRI me R. At the ChGTU experimental mill, by the proposed method, a batch of plates made of rolled tape 0.18 mm thick was rolled. Steel grade 12X18H10T. The diameter of the mill rolls was taken equal to 240 mm so that three corrugated sections were evenly spaced along the perimeter. The tape was deformed in one pass at a rolling speed of 500 mm / s. The drive was the lower roll. The dimensions of the tape and corrugated sections, as well as the transverse profile of the corrugations are shown in FIG. 4 and 5. After rolling, the tape retained flatness. A comparison of the proposed method and the prototype are shown in the table.

Thus, the proposed method allows you to:
reduce the number of operations by 9 times;
increase productivity tenfold;
create in-line mechanized production of plates;
exclude intermediate heat treatments;
reduce the thickness of the walls of the corrugations from 40 to 5%
significantly reduce the cost of plates with corrugated sections.

Claims (1)

A method of manufacturing thin-walled plates with corrugated sections surrounded by flat sections around the perimeter, which consists in shaping by pressure treatment, characterized in that the process is carried out in one step by longitudinal rolling of a tape in two rolls, the calibration of which at the corrugation forming sections is performed from the condition

on one of the rolls along its longitudinal axis make smooth sections of width L _p flush with the base of the calibers at a distance L from each other, corresponding to the length of the corrugated section, while the diameter of the rolls is chosen from the condition

and the gap between the rolls on smooth sections along the edges of the barrels is set equal

where h _{about the} thickness of the original tape;
b _{g the} width of the corrugated area;
h _g wall thickness of the corrugation;
l _{g the} length of the scan corrugated section in the transverse direction to the plane;
λ _{g the} coefficient of metal drawing in the corrugated section in the longitudinal direction;
n the number of corrugated sections along the perimeter of the roll barrel.

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