CN112958886B - A high-efficiency welding method for thick-gauge composite billets - Google Patents

Abstract

The invention relates to a high-efficiency welding method for thick-gauge composite blanks, comprising the following steps: the length and width of the base material are respectively 40-100mm longer than the length and width of the covering material; Install two pieces of cladding material; install the frame in the groove formed by the base plate and the cladding material, and place the bottom edge of the frame at the bottom of the groove and make it symmetrical; the frame divides the groove into two small grooves; use a submerged arc Weld two grooves in sequence. The advantages are: effectively reducing the welding time of the assembly and improving the operation efficiency of the assembly and welding of the composite plate. According to the method of the present invention, the blank assembly efficiency can be increased by at least 50%, and can be increased by more than 1 times for large and thick plates. In addition, since the frame can function as a separator, there is no need to worry about the molten metal flowing into the separator, and there is no need to install the separator, which can eliminate the separator process and improve the yield.

Description

A high-efficiency grouping and welding method for thick-gauge composite billets

technical field

The invention belongs to the field of composite billet welding, and in particular relates to a high-efficiency grouping and welding method for a thick specification heterogeneous composite billet with a thickness of more than 250 mm.

Background technique

Using the rolling composite technology, metals with large differences in chemical composition, strength, melting point and thermal expansion coefficient can be metallurgically combined to form a metal layered composite plate, which has both the bearing capacity of the base metal and the corrosion resistance and resistance of the cladding metal. Oxidation and other special performance properties, while reducing the cost of materials. In the production of composite panels, the assembly of blanks is an important link. By welding, the base material and the cladding material are welded together to form an integral blank, so that the clad plate can be finally produced by rolling. At present, the assembly of heterogeneous composite panels mainly includes two forms of vacuum electron beam assembly and arc welding assembly. The vacuum electron beam assembly has the characteristics of large weld fusion width ratio and fast welding speed. However, the one-time investment of vacuum electron beam welding machine is too large, which limits the use of this method. At the same time, vacuum electron beam welding is easily affected by various factors such as magnetic field, and the welding quality is unstable. Therefore, conventional arc welding is still the most commonly used welding method in the assembly of heterogeneous composite slabs.

In the currently commonly used production process of symmetrical composite panels, the size of the base material is larger than the size of the cladding material, and a groove is formed between the base material and the cladding material. The perimeter of the groove is filled with arc welding to form a weld. In order to prevent the welding molten metal from flowing into the gap between the two cladding materials, a separator with a thickness of about 12-20mm is generally pre-welded on the surface of the cladding materials. The depth of the weld is equal to the dimensional difference between the base material and the cladding material minus the thickness of the separator, and the width of the weld is equal to the thickness of the two cladding materials, see Figure 1.

Since the welding seam is subjected to a large shear force during the rolling process, in order to ensure the smooth completion of the rolling process, the welding seam should ensure sufficient bearing capacity. The load-bearing capacity of the weld depends on the depth of the weld, not on the width of the weld. However, the width of the weld is closely related to the total filling amount of the weld. When the target finished composite panel has a higher specification, the corresponding cladding blank specification also needs to be increased accordingly. The width of the weld often reaches more than 60mm, or even 80-100mm, resulting in a particularly huge welding workload. It takes 30-40 hours to complete the process of forming a pair of composite slabs, and the continuous welding operation deteriorates the welding conditions. In addition, since the separator needs to be welded on the cladding metal, a larger size must be reserved for the base material, which also affects the yield of the final composite board and increases the manufacturing cost. Using the existing technology to produce thick-gauge composite panels, low welding efficiency has become the bottleneck of the entire composite panel production.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a high-efficiency welding method for thick-gauge composite blanks. The composite blanks with a thickness of more than 250 mm can improve the composite blank assembly efficiency on the premise of satisfying the quality of the composite panels. Reduce the cost of composite plate manufacturing and meet the mass production requirements of heterogeneous composite steel plates.

To achieve the above object, the present invention is achieved through the following technical solutions:

A method for high-efficiency grouping and welding of thick-gauge composite billets, comprising the following steps:

1) Billet preparation: two pieces of carbon steel for the base material and two pieces of cladding material, the length and width of the base material are 40-100mm longer than the length and width of the cladding material;

2) Surface processing: the surface to be contacted with the base material and the cladding material is processed to remove the oil, rust and oxide layer on the surface to be contacted; the surface roughness Ra<6μm;

3) Apply release agent after cladding processing, and place it in dry air for ≥12h after applying release agent;

4) Frame processing: the cross section of the frame is an isosceles trapezoid, the height of the trapezoid is half of the length difference between the base material and the composite material, and the lower bottom edge of the trapezoid is the sum of the thicknesses of the two cladding materials minus 8-16mm. The angle between the side and the vertical line is 30°-50°; a pair of composite blanks are processed with 4 frames, two of which are the same length as the base material, and the other two frames are the same length as the width of the composite material;

5) Assembling the blank: place the lower substrate of the composite blank on the bottom layer, and place two cladding materials in sequence; the side of the cladding material coated with the isolation agent is opposite, sandwich the isolation agent in the middle, and finally put the upper substrate of the composite blank; The processing surfaces of the material are opposite to each other. During the placement process, ensure that the cladding material is in the middle of the substrate, and the substrate on each side is 20-50mm longer than the cladding material;

6) Point solidification of the billet: use gas shielded welding to weld the connection between the base material and the cladding material by gas shielded welding;

7) Hoisting: After the point fixing is completed, the blank is hoisted upright with lifting equipment, so that the welding seam to be welded is placed in the flat welding position;

8) Frame installation: Install the frame in the groove formed by the base plate and the cladding material. The bottom edge of the frame is placed at the bottom of the groove and is symmetrical to the left and right; the top edge of the frame trapezoid is flush with the base plate, and gas shielded welding is used after placement. Point-fix the bottom edge of the frame and the cladding material, each point-fixed weld is 50-100mm long, and the spacing is 200-250mm; after point-fixing, the frame divides the groove into two small grooves;

9) Weld two grooves in sequence with submerged arc welding;

10) First weld the weld to be welded at the flat welding position, then weld the weld on the opposite side, the weld on the side, and finally weld the weld on the opposite side of the weld on the side;

11) Check the welding quality, and the welding of the group blank is completed.

The welding current of the submerged arc welding in step 9) is 500-650A, the voltage is 28-33V, and the welding speed is 28-35cm/min.

Step 9) After the two grooves are flattened, the uppermost weld bead covers the groove surface as a whole.

In step 3), the thickness of the release agent is 0.5-1 mm.

Step 10) After the welding of the to-be-welded seam at the flat welding position is completed, turn the blank 180°, repeat steps 8)-step 9), and weld the symmetrical plane; turn the blank 90°, repeat steps 8)-step 9), and weld another side; finally flip 180° and solder the last side.

Compared with the prior art, the beneficial effects of the present invention are:

By optimizing the welding method, the high-efficiency welding method of the thick-gauge heterogeneous composite billet effectively reduces the welding time of the billet and improves the working efficiency of the welding of the composite plate. According to the method of the present invention, the blank assembly efficiency can be increased by at least 50%, and can be increased by more than 1 times for large and thick plates. In addition, since the frame can function as a separator, there is no need to worry about the molten metal flowing into the separator, and there is no need to install the separator, which can eliminate the separator process and improve the yield.

Description of drawings

Figure 1 is a schematic diagram of the original symmetrical composite plate welding structure.

Figure 2 is a schematic diagram of a high-efficiency welding structure of a thick-gauge heterogeneous composite billet.

In the picture: 1- Base material 2- Cladding material 3- Partition plate 4- Weld seam 5- Frame.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings, but it should be pointed out that the implementation of the present invention is not limited to the following embodiments.

Example:

As shown in Figure 2, a high-efficiency welding method for thick-gauge composite billets includes the following steps:

1) Billet preparation: two pieces of carbon steel for the base material and two pieces of cladding material, the length and width of the base material are 50mm longer than the length and width of the cladding material;

2) Surface processing: the surface to be contacted with the base material and the cladding material is processed to remove the oil, rust and oxide layer on the surface to be contacted; the surface roughness Ra<6μm;

3) After the cladding is processed, apply the release agent, the thickness of the release agent is 0.5-1mm, after the release agent is applied, place it in dry air to dry for ≥12h;

4) Frame processing: the cross section of the frame is an isosceles trapezoid, the height of the trapezoid is 30mm, the bottom edge of the trapezoid is the sum of the thicknesses of the two cladding materials and then minus 10mm, the angle between the side and the vertical line of the trapezoid is 40°, and the frame The length is equal to the length and width of the substrate;

5) Assembling the blank: place the lower substrate of the composite blank on the bottom layer, and place two cladding materials in sequence; the side of the cladding material coated with the isolation agent is opposite, sandwich the isolation agent in the middle, and finally put the upper substrate of the composite blank; The processing surfaces of the material are opposite to each other. During the placement process, ensure that the cladding material is in the middle of the substrate, and the substrate on each side is 25mm longer than the cladding material;

6) Point solidification of the billet: Gas-shielded welding is used to weld the connection between the base material and the cladding material, and the 8 fillet welds around it must be welded firmly;

7) Hoisting: After the point fixing is completed, the blank is hoisted upright with lifting equipment, so that the welding seam to be welded is placed in the flat welding position;

8) Frame installation: Install the frame in the groove formed by the base plate and the cladding material. The bottom edge of the frame is placed at the bottom of the groove and is symmetrical to the left and right; the top edge of the frame trapezoid is flush with the base plate, and gas shielded welding is used after placement. Point-fix the bottom edge of the frame and the cladding material, each point-fixed weld is 60mm long, and the spacing is 200mm; after point-fixing, the frame divides the groove into two small grooves;

9) Weld two grooves in turn by submerged arc welding, current 500-650A, voltage 28-33V, welding speed 28-35cm/min; after the two grooves are flattened, the top weld bead covers the groove surface as a whole;

10) After the welding of one side is completed, turn the blank 180°, repeat step 8)-step 9), and weld the symmetrical plane; turn the blank 90°, repeat step 8)-step 9), weld the other side; finally turn it 180°, Weld the last side;

11) Check the welding quality, and the welding of the group blank is completed.

Example:

The examples and comparative examples in the above table are in a one-to-one correspondence. It can be seen that, by adopting the method of the present invention, the consumption of welding material and man-hour consumption are not sensitive to the plate thickness, and the results are close to each other under the conditions of various plate thicknesses, and the main factor is the length and width of the blank. The traditional process has a great relationship with the thickness of the plate. As the thickness of the plate increases, the consumption of welding consumables and man-hours increase significantly. The results of the above examples and comparative processes show that the use of the present invention is more conducive to reducing the cost of blank assembly and improving the welding production efficiency.

Claims (4)

1. a thick specification composite billet high-efficiency group billet welding method, is characterized in that, comprises the following steps: 1) Billet preparation: two pieces of carbon steel for the base material and two pieces of cladding material, the length and width of the base material are 40-100mm longer than the length and width of the cladding material; 2) Surface processing: the surface to be contacted with the base material and the cladding material is processed to remove the oil, rust and oxide layer on the surface to be contacted; the surface roughness Ra<6μm; 3) Apply release agent after cladding processing, and place it in dry air for ≥12h after applying release agent; 4) Frame processing: the cross section of the frame is an isosceles trapezoid, the height of the trapezoid is half of the difference between the length of the base material and the cladding material, and the bottom edge of the trapezoid is the sum of the thicknesses of the two cladding materials minus 8-16mm. The angle between the side and the vertical line is 30°-50°; a pair of composite blanks are processed with 4 frames, two of which are the same length as the base material, and the other two frames are the same as the width of the cladding material; 5) Assembling the blank: place the lower substrate of the composite blank on the bottom layer, and place two cladding materials in sequence; the side of the cladding material coated with the isolation agent is opposite, sandwich the isolation agent in the middle, and finally put the upper substrate of the composite blank; The processing surfaces of the material are opposite to each other. During the placement process, ensure that the cladding material is in the middle of the substrate, and the substrate on each side is 20-50mm longer than the cladding material; 6) Point solidification of the billet: use gas shielded welding to weld the connection between the base material and the cladding material by gas shielded welding; 7) Hoisting: After the point fixing is completed, the blank is hoisted upright with lifting equipment, so that the welding seam to be welded is placed in the flat welding position; 8) Frame installation: Install the frame in the groove formed by the base plate and the cladding material. The bottom edge of the frame is placed at the bottom of the groove and is symmetrical to the left and right; the top edge of the frame trapezoid is flush with the base plate, and gas shielded welding is used after placement. Point-fix the bottom edge of the frame and the cladding material, each point-fixed weld is 50-100mm long, and the spacing is 200-250mm; after point-fixing, the frame divides the groove into two small grooves; 9) Weld two grooves in sequence with submerged arc welding; 10) First weld the weld to be welded at the flat welding position, then weld the weld on the opposite side, the weld on the side, and finally weld the weld on the opposite side of the weld on the side; After the welding of the to-be-welded seam at the flat welding position is completed, turn the blank 180°, repeat steps 8)-9), and weld the symmetrical plane; turn the blank 90°, repeat steps 8)-step 9), and weld the other side; finally Flip 180° and weld the last side; 11) Check the welding quality, and the welding of the group blank is completed. 2. A kind of high-efficiency welding method for thick specification composite billet according to claim 1, characterized in that, the welding current of the submerged arc welding in step 9) is 500-650A, the voltage is 28-33V, and the welding speed is 28 -35cm/min. 3. A method for high-efficiency grouping and welding of thick-gauge composite billets according to claim 1, wherein in step 9) after the two grooves are flattened, the uppermost weld bead covers the groove surface as a whole. 4. The high-efficiency welding method for forming a thick-gauge composite billet according to claim 1, wherein the thickness of the release agent in step 3) is 0.5-1 mm.

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