SU1671428A1 - Method to fabricate workpieces of annular configuration - Google Patents

Abstract

The invention relates to flash butt welding, and can be used in the manufacture of parts in production where bending, welding, stamping and rolling are used. The purpose of the invention is to increase productivity by eliminating additional machining, reducing metal consumption, energy intensity of the process, improving the quality of welded joints. The method includes heating a strip of dimensional length, hot forming a closed billet, and welding, with the billet being made with specified dimensions. After welding, the burr is removed and the ring billet is plastically deformed in the stamp or by ball or radial rolling. For radial rolling of products with a diameter of more than 400 mm, the cross-sectional area of the workpiece is preliminarily determined from a given ratio. The method allows to increase the stability of the quality of the obtained products. 3 hp f-ly, 3 ill., 1 tab.

Description

The invention relates to resistance butt welding and can be used in the manufacture of parts of a ring-shaped structure in production, where bending, welding, stamping and rolling are used.

The purpose of the invention is to increase labor productivity by eliminating additional machining, reducing metal consumption, energy intensity, and improving the quality of welded joints.

Figure 1 is a diagram of hot, die-forgive stamping in closed dies; 2 is a diagram of hot stamping in open dies; on fig.Z - the flange obtained by rolling the workpiece, the cross section.

The method is carried out as follows.

Linear billets of measured length with edges cut to such an angle that, after bending into a ring, they are parallel, are placed in a gas oven with a walking hearth. In the furnace, they are heated to 900-1000 ° C and are conveyed through the conveyor to the php. Bending, which by means of bending to the edge around the mandrel, bends the dimensional blank into a ring. The molded closed workpiece is conveyed to a butt welding machine, where it is welded, then fed to a deburring machine. After deburring, the welded billet is fed into the press stamp, where, simultaneously with the calibration, the x |

Ј 10 00

The required ring profile is shown (Figures 1 and 2).

The whole process of making a closed blank lasts about 1.5 minutes. During this time, the billet but only does not cool, and during the welding process the shunt portion of the annular billet is also additionally heated. The plastic deformation operation is usually performed at a higher billet temperature than that which the annular billet had before welding. This temperature provides such mechanical properties of the metal, which make it possible to perform volumetric plastic deformation with large reduction points,

When making ring fillings (flanges), I get the best results when I measure the length of the workpiece, the diameter of the flange bend mandrel and rel: welding them is so chosen that, before plastic deformation, the smallest axis of the internal contour of the workpiece is 0.8-0, 9 of the inner diameter of the finished product, and the inner perimeter - 0.8-0.95 of the inner perimeter of the finished product.

After welding, the ring blank loses its original geometric shape and looks like an oval or ellipse. Experiments were carried out to determine the specified limits for the minimum diameter of the ring ensemble and the length of its perimeter. Plastic deformation of the ring billet was performed by a conical mandrel, which gradually goes into the internal volume of the ring billet. It was found that the coefficient of volumetric plastic deformation is evenly distributed around the perimeter of the ring billet, or unevenly distributed around the perimeter of the ring billet, and at certain ratios of the minimum diameter and perimeter of the ring billet, there were cases of no volumetric plastic deformation in some volumes of the ring billet. In any case, the annular billet has an irregular section.

The proposed method of selecting the optimal size of the workpiece provides ring blanks with. using stamping for small diameters (up to 400 mm) and face rolling for large diameters (over 400 mm). But there are a significant number of cross-section configurations that are difficult or impossible to obtain by stamping or face rolling, but easy radial rolling. A special feature of radial rolling (without using closed gauges) is

the fact that after rolling increases the diameter of the annular billet. In this case, the ratio of cross-sectional areas before and after rolling is inversely proportional to the ratio of the lengths of the lines connecting the centers of mass of the cross-sections.

When applying rolling in closed calibers, as well as radial-yurtsovy rolling, you can get a lot of options for rings of different sections and diameters.

In some cases, after welding and stripping, the ring billet is unevenly heated. Therefore, 1 volume operation

plastic deformation is delayed by reducing the speed of the conveyor. During the time that the ring billet travels the distance from the press to remove the flash to the press or roll machine,

the temperature due to heat conduction is equalized.

Departing from the optimal ratios of the internal diameter and internal perimeter of the blanks before and after

volumetric plastic deformation, the cross-section of the finished ring billet is unequal in length. Therefore, in this case, an increase in the machining allowance is required, which leads to metal loss

and electricity,

The choice of the cross-sectional area of the workpiece, which is chosen as follows, has a significant impact on the quality of the welded joint when using radial rolling of the flange blank.

Having the geometrical dimensions of the required annular billet, calculate its cross section F, then the transverse

The section is disassembled into simple geometric figures, for which the formulas for calculating the coordinates of the center of mass or center of gravity are known. The coordinates of the center of mass or center of gravity (in our case they are

match) calculated by the formula

Y - V F Hs.m.

where FI is the area of a simple geometric figure;

Xi is the coordinate of the center of mass of a simple geometric figure with respect to an arbitrarily chosen point;

F is the complete cross section of the ring billet.

The volume of the ring billet is equal to

P F-IC

where (c is the length of the lines connecting the centers of mass, or 1C JtDc, where Dc is the diameter of the centers of mass.

The next step in the calculation is the selection of the cross section of the strip from which the blank will be made for rolling. The following are guided by this. 1 strip thickness should be slightly greater than the maximum thickness of the ring binder. The cross-sectional area of the strip should be about 10% larger than the cross-sectional area of the ring clamp after rolling.

After selecting a strip, its length is calculated along the line connecting the centers of the seam, the welding allowance is added, and the length of the original measuring strip is obtained along the line connecting the centers of mass. The bends are flexible and calculate the size of the mandrel for sanding on the edge. After bending and welding, the receipt of the workpiece required for rolling is guaranteed.

Figure 1 shows the calculation results for a flange of DN 600 PN 10.

Example. The cross section of the flange is shown in figure 1. We break it into rectangles 80x31 and 34x5. We select the axis of symmetry of the flange as the reference line, we find the race radius of the center of mass of the cross section

v 31 80 351 +34 5 328 n., hr X --5-o 349 (mm)

where 2650 is the cross-sectional area of the flange.

The length of the line connecting the centers of mass is equal to (from 2лХ -2-3,14-349 2193 (mm)

The volume of the finished flange is equal to Р F-lc 2650 2193 5811004 (mm3).

In accordance with the recommendations, we choose according to the assortment of the section of the 40x70 measuring strip with a cross-sectional area of 2800 mm.

The length of the measuring strip along the line connecting the centers of mass is equal to

Lee-: ig, connecting the centers of mass of the measured workpiece, and its median line coincide.

The results of the survey of the method are attached to the table.

In the described method of metal loss

equal to the metal loss during welding, which is a fraction of a percent of the weight of the workpiece.

As described in the table, the method allows to significantly increase the stability of the quality of the products obtained.

Claims (4)

Invention Formula 1, a method of manufacturing ring-shaped products, including cutting a strip of measured length, taking into account the allowance for melting and slumping, hot forming a closed billet, welding, deburring, which, in order to increase productivity by eliminating additional mechanical processing, reducing metal consumption, energy intensity of the process, improving the quality of welded joints, a closed workpiece is made of a strip or rod with a length of section forming an internal the surface of the workpiece after welding, 0.8–0.95, the inner perimeter of the finished product, is formed into a workpiece with the smallest axis of the inner contour equal to 0.8–0.9 of the internal diameter of the finished product, and after removal of the burr, the preparation is subjected to bulk plastic deformation. 2. A method according to claim 1, characterized in that in the case of manufacturing products of small diameter, after the deburring, the preform is stamped. 3 The method according to claim 1, wherein what about the case of manufacturing large diameter articles after deburring the workpiece is subjected to radial or end rolling. 4. The method of paragraph 3, characterized by IBM, that the workpiece before radial rolling is performed with a cross-sectional area F3ar, which is determined from the ratio with Reed  eag ed Ј F 5811004 2800  2075 (mm) Adding a welding allowance equal to 20 mm, we obtain the length of the measured blank along the line connecting the centers of mass to the flexible one. where Rschd - the cross-sectional area of the product of the annular form of half-rolling; 1, the length of the line connecting the centers of mass of the ring-shaped product after rolling; 13a is the length of the line connecting the centers of mass of the workpiece before rolling. Lane t f 625 jJnooflpaBKe F 7 & flS Ф622- Fig.Z