A stainless steel grid plate welding process

Abstract

The invention discloses a stainless steel grid plate welding process, comprising the following steps: S1, lofting; S2, preparation before welding; S3, assembly and spot welding of longitudinal ribs, transverse ribs and outer circular plates; S4, spot welding to form a second stainless steel grid plate blank; S5, placing a plurality of connecting flat steels; S6, completely aligning and overlapping the first stainless steel grid plate blank and the second stainless steel grid plate blank; S7, spot welding to form a stacked grid assembly stacked up and down; S8, placing the stacked grid assembly horizontally on a support frame; S9, welding the first stainless steel grid plate blank and the second stainless steel grid plate blank on the stacked grid assembly at the same time; S10, cutting and grinding to remove the spot welding points; S11, post-welding inspection. The method can weld stainless steel grid plates more accurately and reduce stress deformation during welding.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a welding process for a stainless steel grid plate on a modular chemical pressure vessel. Background Art

[0002] In the process of modularizing chemical pressure vessels in some chemical production equipment, large-sized stainless steel grid plates are needed. The material of stainless steel is SA240 316L. This large-sized stainless steel grid plate mainly includes multiple parallel longitudinal ribs, multiple transverse ribs and outer circular plates. The outer circular plate surrounds the outer edge of the longitudinal ribs and transverse ribs for a circumference, wherein the number of longitudinal ribs is greater than the number of transverse ribs, and each transverse rib includes several transverse rib segments, which are welded as a whole to form a grid shape. The diameter of this large-sized stainless steel is generally between three meters and eight meters, but the requirements for this large-sized stainless steel grid plate are very high, especially the surface levelness of the stainless steel grid plate must be controlled within ±1mm, which puts more stringent requirements on the production of stainless steel grid plates. Since the number of welds in the production of stainless steel grid plates is very large, deformation is easy to occur after welding, and the larger the size, the more significant the welding deformation. Therefore, the current conventional welding process cannot meet the above-mentioned process technology requirements. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a stainless steel grid plate welding process, which can weld the stainless steel grid plate more accurately and reduce stress deformation during welding.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a stainless steel grid plate welding process, comprising the following steps:

[0005] S1. Lofting

[0006] Marking and setting out on the stainless steel platform in accordance with the drawing size of the design drawing at 1:1, thereby forming a marking pattern on the stainless steel platform that is completely identical to the shape of the stainless steel grid plate, wherein the stainless steel grid plate comprises a plurality of parallel longitudinal ribs, a plurality of transverse ribs and an outer circular plate, wherein the outer circular plate surrounds the longitudinal ribs and the transverse ribs, wherein the number of the longitudinal ribs is greater than the number of the transverse ribs, and each transverse rib includes a plurality of transverse rib plate segments;

[0007] S2. Preparation before welding;

[0008] S3, the assembly and spot welding of the longitudinal ribs, transverse ribs and outer circular plates, including the following steps:

[0009] S31, remove the burrs on the cut end faces of each component and clean the pollutants around the welding parts to expose the metallic luster;

[0010] S32, placing the outer circular plate, the longitudinal rib plate and the transverse rib plate segments one by one on the stainless steel platform according to the marking pattern, and supported by the spot-fixing blocks spot-fixed and welded to the stainless steel platform;

[0011] S33, spot welding the outer circular plate, the longitudinal rib plate and the transverse rib plate to each other to form a first stainless steel grid plate blank;

[0012] S4, after removing the first stainless steel grid plate blank, repeat steps S2 and S3 to spot weld to form a second stainless steel grid plate blank;

[0013] S5. Place a plurality of connecting flat steel bars on the second stainless steel grid plate blank, with both ends of the connecting flat steel bars exceeding the outline of the outer circular plate;

[0014] S6, stacking the first stainless steel grid plate blank on the connecting flat steel, and making the first stainless steel grid plate blank and the second stainless steel grid plate blank completely aligned and overlapped;

[0015] S7, spot welding the first stainless steel grid plate blank, the second stainless steel grid plate blank and the connecting flat steel to form a stacked grid assembly stacked up and down;

[0016] S8, placing the stacked grid assembly horizontally on the support frame;

[0017] S9. Simultaneously weld the first stainless steel grid plate blank and the second stainless steel grid plate blank on the stacked grid assembly at the same position, first weld the fillet weld between the longitudinal rib plate and the transverse rib plate segment, then weld the fillet weld between the outer circular plate and the longitudinal rib plate, and between the outer circular plate and the transverse rib plate segment; when the tangent angle between the outer circular plate and the longitudinal rib plate and the transverse rib plate is less than 45°, do not weld the fillet weld on that side; use consumable flux-cored wire carbon dioxide gas shielded welding to perform symmetrical welding, vertical welding, continuous welding, single-layer single-pass welding, reflow arc starting, arc closing to fill the arc pit;

[0018] S10, after being completely cooled, cutting and grinding to remove the spot welding points between the connecting flat steel and the first stainless steel grid plate and the second stainless steel grid plate, so that the spot welding scars on the surface of the longitudinal rib plate are flush with the end surface of the longitudinal rib plate;

[0019] S11. Inspection after welding.

[0020] Preferably, in step S1, each marking line in the marking pattern corresponding to the longitudinal rib plate, outer circular plate, and transverse rib plate segment includes two rib plate contour lines on both sides and a rib plate center line in the middle, so that when the marking lines are aligned one by one with the longitudinal rib plate, outer circular plate, and transverse rib plate segments, the contours can be better aligned, and the center line can ensure that the transverse rib plate formed by the transverse rib plate segments and the longitudinal rib plate are in the same straight line.

[0021] Preferably, the pre-welding preparation in step S2 includes:

[0022] S21. Qualification check of welders;

[0023] S22. Test the parent material, welding machine, welding material and shielding gas;

[0024] S23. Check the dimensions of the outer circular plate, longitudinal rib plate, and transverse rib plate sections.

[0025] Preferably, in step S32, the outer circular plate, the longitudinal rib plate and the transverse rib plate segments are placed one by one on the stainless steel platform according to the line pattern, and supported by the spot-fixed blocks spot-welded to the stainless steel platform. The specific steps are:

[0026] S321, first placing the outer circular plate on the marking line corresponding to the scribing pattern;

[0027] S322, after supporting the outer circular plate with a plurality of spot fixing blocks, spot-welding the spot fixing blocks to the stainless steel platform;

[0028] S323, placing the longitudinal ribs one by one on the corresponding marks, using the spot fixing block to support each longitudinal rib, and then adjusting the state of the longitudinal ribs to make them perpendicular to the stainless steel platform by measuring with a square, and then spot welding the spot fixing block to the stainless steel platform;

[0029] S324. After all the longitudinal ribs are placed and assembled, assemble the transverse rib segments in the same manner as in step S323. The thickness of the spot fixing blocks is 5-8 mm. Due to the long length of the longitudinal ribs, the longitudinal ribs are placed and assembled first. This is more conducive to limiting and constraining the assembly position of the transverse rib segments, ensuring that the transverse rib segments are accurately positioned during placement and assembly.

[0030] Preferably, the spot welding sequence of the connecting flat steel in step S7 is:

[0031] S71, first weld the spot welding points between the connecting flat steel and the longitudinal rib plate near the center, and then weld the spot welding points between the connecting flat steel and the longitudinal rib plate far from the center;

[0032] S72. When welding each connecting flat steel, spot weld symmetrically from the midpoint of the connecting flat steel to the left and right sides. During spot welding, the spot welds at the same position of the connecting flat steel and the first stainless steel grid plate blank and the second stainless steel grid plate blank are welded simultaneously by different people; the spot welds after spot welding are symmetrical with respect to the midpoint of the connecting flat steel; the length of the spot weld is 15-25mm; the welding height is greater than 5mm; the welding process regulations for spot welding are the same as those for formal welding, so the above-mentioned spot welding sequence can minimize the deformation of the first stainless steel grid plate blank and the second stainless steel grid plate blank during spot welding.

[0033] Preferably, in step S9, the welding sequence of the fillet weld between the longitudinal rib plate and the transverse rib plate segment is:

[0034] S91. All longitudinal ribs form a plurality of longitudinal strip grids, and transverse rib plate segments are correspondingly arranged in the longitudinal strip grids; firstly, the transverse rib plate segments in the central longitudinal strip grid are welded, and then the transverse rib plate segments are welded one longitudinal strip grid apart on the left and right sides to implement the first symmetrical jump welding; after the first symmetrical jump welding is completed, the transverse rib plate segments in a longitudinal strip grid on the left or right side of the central longitudinal strip grid are welded, and then the transverse rib plate segments are welded one longitudinal strip grid apart on the left and right sides to implement the second symmetrical jump welding;

[0035] S92. All transverse rib plate segments within each longitudinal strip grid are diffusion welded from the center to the outside.

[0036] This welding method can offset the welding stress during welding and reduce welding deformation as much as possible.

[0037] Preferably, the welding sequence of the fillet welds between the outer circular plate and the longitudinal rib plate, and between the outer circular plate and the transverse rib plate segment in step S9 is: multiple people weld in a counterclockwise direction at the same time, and the welding positions of multiple people are evenly distributed relative to the center circumference of the stainless steel grid plate blank. In this way, when welding the fillet welds on the outer original plate, multiple people weld evenly around the circumference, which offsets the welding stress as much as possible and avoids deformation of the outer circular plate.

[0038] Preferably, in step S6, the alignment method between the first stainless steel grid plate blank and the second stainless steel grid plate blank is: positioning is performed using at least one pair of transverse positioning blocks and at least one pair of longitudinal positioning blocks; the transverse positioning blocks are spot welded on the stainless steel platform to position and cooperate with the two side surfaces of one of the transverse rib plate segments, and the longitudinal positioning blocks are spot welded on the stainless steel platform to position and cooperate with the two side surfaces of one of the longitudinal rib plates. The heights of the transverse positioning blocks and the longitudinal positioning blocks are greater than the thickness of the first stainless steel grid plate blank. Therefore, accurate positioning can be achieved by using the transverse positioning blocks and the longitudinal positioning blocks, and the transverse positioning blocks and the longitudinal positioning blocks can also be used as spot fixing blocks.

[0039] After adopting the above technical scheme, the effects of the present invention are as follows: 1. In the welding process, a line pattern is first drawn on the stainless steel platform, so that the longitudinal rib plate, the transverse rib plate segment and the outer circular plate can be better positioned when they are assembled; ensuring accurate positioning; 2. The stainless steel grid plate blank is assembled using the spot fixing block, and the spot fixing block is not spot welded with the longitudinal rib plate, the transverse rib plate segment and the outer circular plate, which reduces the deformation during spot fixing welding and can also reduce the subsequent removal of the spot fixing block; 3. The welding process uses the connecting flat steel to weld two completely aligned first stainless steel grid plate blanks and the second stainless steel grid plate blanks to form a stacked grid assembly, and then welds the first stainless steel grid plate blank and the second stainless steel grid plate blank at the same position at the same time. The second stainless steel grid plate blank, so that the stresses generated by the first stainless steel grid plate blank and the second stainless steel grid plate blank during welding will be opposite, and then the welding stress will be offset as much as possible through the interconnected connecting flat steels, thus reducing the deformation during welding; 4. After thorough cooling, cut and grind to remove the spot welding points between the connecting flat steel and the first stainless steel grid plate and the second stainless steel grid plate. At this time, when the spot welding points are removed, no additional deformation will be generated to the first stainless steel grid plate and the second stainless steel grid plate, so that two completely identical first stainless steel grid plates and second stainless steel grid plates are finally welded at the same time, and the horizontality of the end faces of the two grid plates can be controlled within ±1mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0041] Figure 1 is a schematic diagram of assembling a first stainless steel grid plate blank according to an embodiment of the present invention;

[0042] Figure 2 is a top view of the stacked grid assembly;

[0043] Figure 3 is a side view of a stacked grid assembly;

[0044] Figure 4 This is the top view of the welding after the first symmetrical jump welding;

[0045] Figure 5 This is a schematic diagram of the steps for the first symmetrical soldering;

[0046] Figure 6 This is the top view of the welding after the second symmetrical jump welding;

[0047] Figure 7 This is a schematic diagram of the steps for the second symmetrical soldering;

[0048] In the attached drawings: 1. stainless steel platform; 2. outer circular plate; 3. longitudinal rib plate; 4-1. middle transverse rib plate; 4-2. outer transverse rib plate; 41. transverse rib plate segment; 5-1. middle connecting flat steel; 5-2. outer connecting flat steel; 6. first stainless steel grid plate blank; 7. second stainless steel grid plate blank; 8. stacked grid assembly. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below through specific examples.

[0050] like Figures 1 to 6 As shown, a stainless steel grid plate welding process includes the following steps:

[0051] S1. Lofting

[0052] On the stainless steel platform 1, a marking pattern having the same shape as the stainless steel grid plate is formed by marking and setting out according to the drawing size of the design drawing in a ratio of 1:1. The marking pattern is drawn with a stone pencil, wherein the stainless steel grid plate includes a plurality of parallel longitudinal ribs 3, a plurality of transverse ribs and an outer circular plate 2, wherein the outer circular plate surrounds the longitudinal ribs 3 and the transverse ribs, wherein the number of the longitudinal ribs 3 is greater than the number of the transverse ribs, and each transverse rib includes a plurality of transverse rib segments 41; Figure 1 The transverse ribs include a middle transverse rib 4-1 located in the middle and outer transverse ribs 4-2 located on both sides, and there are three transverse ribs in total. The longitudinal rib 3 can be made of a whole plate, or it can be made of multiple sections of plates welded and shaped together. Similarly, the outer circular plate 2 can also be welded after the plate is rolled. The welded longitudinal ribs 3 and outer circular plates 2 can only be used for subsequent assembly and welding after they meet the requirements of the drawings.

[0053] Preferably, in step S1, each marking line in the marking pattern corresponding to the longitudinal rib 3, the outer circular plate 2, and the transverse rib segment 41 includes two rib contour lines on both sides and a rib center line in the middle, so that when the marking lines are aligned one by one with the longitudinal rib 3, the outer circular plate 2, and the transverse rib segment 41, the contour alignment can be better performed, and the center line can ensure that the transverse ribs formed by each transverse rib segment 41 and the longitudinal rib 3 are all on the same straight line.

[0054] S2. Preparation before welding;

[0055] Preferably, the pre-welding preparation in step S2 includes:

[0056] S21. Qualification check of welders;

[0057] S22. Test the parent material, welding machine, welding material and shielding gas;

[0058] Among them, the material number of the base material is SA240 316L, the thickness is 6mm; the welding machine is Panasonic two-protection welding machine YD-500KR2HVE; the welding material model is E316LT1-1, the diameter is 1.2mm; the shielding gas is carbon dioxide, and the purity of the shielding gas is determined to be 99.99% during inspection;

[0059] S23, inspect the dimensions of the outer circular plate 2, the longitudinal rib plate 3, and the transverse rib plate segment 41, including inspecting their thickness, length, width, and roundness.

[0060] S3, the assembly and spot welding of the longitudinal rib plate 3, the transverse rib plate and the outer circular plate 2, includes the following sub-steps:

[0061] S31. Remove burrs from the cut end faces of each component and clean up pollutants within 20 mm around the welding area to reveal the metallic luster; the pollutants removed include oil, moisture, oxide film, etc.

[0062] S32, placing the outer circular plate 2, the longitudinal rib plate 3 and the transverse rib plate segment 41 one by one on the stainless steel platform 1 according to the marking pattern, and supported by the spot-fixing blocks spot-fixedly welded to the stainless steel platform 1;

[0063] Preferably, in step S32, the outer circular plate 2, the longitudinal rib plate 3 and the transverse rib plate segment 41 are placed one by one on the stainless steel platform 1 according to the line pattern, and supported by the spot-fixed blocks spot-fixedly welded to the stainless steel platform 1. The specific steps are:

[0064] S321, first place the outer circular plate 2 on the marking line corresponding to the scribing pattern;

[0065] S322, after supporting the outer circular plate 2 with a plurality of spot fixing blocks, spot-fix welding the spot fixing blocks to the stainless steel platform 1;

[0066] S323, place the longitudinal ribs 3 one by one on the corresponding marks, use the spot fixing block to support each longitudinal rib 3, and then adjust the state of the longitudinal rib 3 to make it perpendicular to the stainless steel platform 1 by measuring with a square, and then spot weld the spot fixing block to the stainless steel platform 1, so that the spot fixing block will support the longitudinal rib 3 to keep it perpendicular to the stainless steel platform 1;

[0067] S324. After all the longitudinal ribs 3 are placed and assembled, assemble the transverse rib segments 41 in the same manner as in step S323. The thickness of the spot fixing block is 5-8 mm. Since the longitudinal ribs 3 are long, the longitudinal ribs 3 are placed and assembled first. This is more conducive to limiting and constraining the assembly position of the transverse rib segments 41, ensuring that the transverse rib segments 41 are accurately positioned during placement and assembly.

[0068] S33, spot-welding the outer circular plate 2, the longitudinal rib plate 3 and the transverse rib plate to each other to form a first stainless steel grid plate blank 6. The length of the spot welding point should not be too long, and the preferred length is 5-8 mm.

[0069] S4, after removing the first stainless steel grid plate blank 6, repeat steps S2 and S3 to spot weld to form a second stainless steel grid plate blank 7; the first stainless steel grid plate blank 6 and the second stainless steel grid plate blank 7 have exactly the same size and shape.

[0070] S5, placing a plurality of connecting flat steels on the second stainless steel grid plate blank 7, with both ends of the connecting flat steels exceeding the outline of the outer circular plate 2; Figure 2 As shown, there are four connecting flat steels which are arranged in parallel and at equal intervals, wherein the connecting flat steels include two middle connecting flat steels 5-1 close to the center area and two outer connecting flat steels 5-2 close to the outer sides, and the material of the connecting flat steels is the same as that of the parent material.

[0071] S6, placing the first stainless steel grid plate blank 6 on the connecting flat steel, and completely aligning and overlapping the first stainless steel grid plate blank 6 and the second stainless steel grid plate blank 7;

[0072] The alignment method of step S6 is: use at least one pair of transverse positioning blocks and at least one pair of longitudinal positioning blocks for positioning; the transverse positioning block is spot welded on the stainless steel platform 1 to position and cooperate with the two side surfaces of one of the transverse rib plate segments 41, and the longitudinal positioning block is spot welded on the stainless steel platform 1 to position and cooperate with the two side surfaces of one of the longitudinal rib plates 3. The height of the transverse positioning block and the longitudinal positioning block is greater than the thickness of the first stainless steel grid plate blank 6, so the transverse positioning block and the longitudinal positioning block can be used for accurate positioning, and the transverse positioning block and the longitudinal positioning block can also be used as spot fixing blocks. In this embodiment, the thickness of the first stainless steel grid plate blank 6 is 76mm, so the height of the transverse positioning block and the longitudinal positioning block can be 10-20mm higher than the height of the first stainless steel grid plate blank 6.

[0073] S7, spot welding the first stainless steel grid plate blank 6, the second stainless steel grid plate blank and the connecting flat steel to form a stacked grid assembly 8 stacked up and down;

[0074] Preferably, the spot welding sequence of the connecting flat steel in step S7 is:

[0075] S71, first weld the spot welding points between the middle connecting flat steel 5-1 and the longitudinal rib plate 3 close to the center, and then weld the spot welding points between the outer connecting flat steel 5-2 and the longitudinal rib plate 3 away from the center;

[0076] S72. When welding each connecting flat steel, spot weld symmetrically from the midpoint of the connecting flat steel to the left and right sides. During spot welding, the spot welds at the same position of the connecting flat steel and the first stainless steel grid plate blank 6 and the second stainless steel grid plate blank 7 are welded simultaneously by different people; the spot welds after spot welding are symmetrical with respect to the midpoint of the connecting flat steel; the length of the spot weld is 15-25mm; the welding height is greater than 5mm; the welding process regulations for spot welding are the same as those for formal welding, so the above-mentioned spot welding sequence can minimize the deformation of the first stainless steel grid plate blank 6 and the second stainless steel grid plate blank 7 during spot welding.

[0077] S8. Place the stacked grid assembly 8 horizontally on a support frame; the support frame elevates the stacked grid assembly 8, which facilitates welding of the first stainless steel grid plate and the second stainless steel grid plate.

[0078] S9, welding the first stainless steel grid plate blank 6 and the second stainless steel grid plate blank 7 on the stacked grid assembly 8 at the same position, first welding the fillet weld between the longitudinal rib plate 3 and the transverse rib plate segment 41, and then welding the fillet welds between the outer circular plate 2 and the longitudinal rib plate 3, and between the outer circular plate 2 and the transverse rib plate segment 41; when the tangent angle between the outer circular plate 2 and the longitudinal rib plate 3 and the transverse rib plate is less than 45°, the fillet weld on this side is not welded but only single-sided welding is performed, and the fillet weld with a tangent angle greater than 45° is welded on both sides; symmetrical welding is performed using consumable electrode flux-cored wire carbon dioxide gas shielded welding, vertical welding, continuous welding, single-layer single-pass welding, arc starter, arc endurance to fill the arc pit;

[0079] In step S9, the welding sequence of the fillet weld between the longitudinal rib plate 3 and the transverse rib plate segment 41 is:

[0080] S91, all longitudinal ribs 3 form a plurality of longitudinal strip grids, and the transverse rib plate segments 41 are correspondingly arranged in the longitudinal strip grids; firstly weld the transverse rib plate segments 41 in the central longitudinal strip grid, and then weld the transverse rib plate segments 41 one by one on the left and right sides to perform the first symmetrical jump welding;

[0081] After the first symmetrical jump welding is completed, the transverse rib plate segment 41 in a longitudinal strip grid on the left or right side of the central longitudinal strip grid is welded, and then the second symmetrical jump welding is performed in sequence with each longitudinal strip grid being alternated.

[0082] S92. All transverse rib plate segments 41 in each longitudinal strip grid are diffusion welded from the center to the outside.

[0083] like Figure 5 As shown, Figure 5FIG. 1 shows the welding process of the first symmetrical jump welding, wherein all the transverse rib plate segments 41 in the longitudinal strip grid A are welded first, wherein there are a total of three transverse rib plate segments 41 in the longitudinal strip grid A, then the transverse rib plate segment 41 in the middle is welded first, and after the welding of the transverse rib plate segment 41 in the middle is completed, the transverse rib plate segment 41 on the outside is welded, and then symmetrical jump welding is performed in the same manner, and the longitudinal strip grids B to G are welded in sequence. After the welding is completed, the second symmetrical jump welding is performed, as shown in FIG. Figure 6 As shown, at this time, the longitudinal strip grids H to O are welded in sequence, so that the longitudinal rib plate 3 and all the transverse rib plate segments 41 can be welded completely.

[0084] The welding sequence of the fillet welds between the outer circular plate 2 and the longitudinal rib plate 3, and between the outer circular plate 2 and the transverse rib plate segment 41 in step S9 is as follows: multiple people weld in a counterclockwise direction at the same time, and the welding positions of multiple people are evenly distributed relative to the center circumference of the stainless steel grid plate blank. In this way, when welding the fillet welds on the outer original plate, multiple people weld evenly around the circumference, which offsets the welding stress as much as possible and avoids deformation of the outer circular plate 2.

[0085] S10, after being completely cooled, cutting and grinding to remove the spot welding points between the connecting flat steel and the first stainless steel grid plate and the second stainless steel grid plate, so that the spot welding scars on the surface of the longitudinal rib plate 3 are flush with the end surface of the longitudinal rib plate 3;

[0086] S11. Inspection after welding.

[0087] Post-weld inspection includes testing the surface level of the stainless steel grille, which is acceptable if it is within ±1mm; checking the outer diameter of the stainless steel grille plate, which is acceptable if it is within ±10mm; checking the spacing of the stainless steel grille plates, which is acceptable if the spacing error between the grille plates is within ±6mm; checking the thickness of the stainless steel grille, which is acceptable if it is within ±2mm;

[0088] Other process requirements in the above welding process:

[0089] 1. During welding, it is strictly forbidden to strike an arc on the surface of the parent material other than the weld;

[0090] 2. Welding parameters must be strictly in accordance with the range specified in the welding procedure qualification WPS;

[0091] 3. During the welding operation, the welder should pay attention to the equal height of the weld angles on both sides and the outer surface of the weld should be straight or concave;

[0092] 4. After each weld is completed, clean the slag, spatter and other defects on the weld surface, and grind and remove the cracks at the arc starting and ending points (if any).

[0093] At this point, the welding process parameters of the stainless steel grid plate are as follows:

[0094]

[0095] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Various modifications and alterations to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A stainless steel grid plate welding process, characterized in that: The following steps are involved: S1. Lofting Marking and setting out on the stainless steel platform in accordance with the drawing size of the design drawing at 1:1, thereby forming a marking pattern on the stainless steel platform that is completely identical to the shape of the stainless steel grid plate, wherein the stainless steel grid plate comprises a plurality of parallel longitudinal ribs, a plurality of transverse ribs and an outer circular plate, wherein the outer circular plate surrounds the longitudinal ribs and the transverse ribs, wherein the number of the longitudinal ribs is greater than the number of the transverse ribs, and each transverse rib includes a plurality of transverse rib plate segments; S2. Preparation before welding; S3, the assembly and spot welding of the longitudinal ribs, transverse ribs and outer circular plates, including the following steps: S31, remove the burrs on the cut end faces of each component and clean the pollutants around the welding parts to expose the metallic luster; S32, placing the outer circular plate, the longitudinal rib plate and the transverse rib plate segments one by one on the stainless steel platform according to the marking pattern, and supported by the spot-fixing blocks spot-fixed and welded to the stainless steel platform; S33, spot welding the outer circular plate, the longitudinal rib plate and the transverse rib plate to each other to form a first stainless steel grid plate blank; S4, after removing the first stainless steel grid plate blank, repeat steps S2 and S3 to spot weld to form a second stainless steel grid plate blank; S5. Place a plurality of connecting flat steel bars on the second stainless steel grid plate blank, with both ends of the connecting flat steel bars exceeding the outline of the outer circular plate; S6, stacking the first stainless steel grid plate blank on the connecting flat steel, and completely aligning and overlapping the first stainless steel grid plate blank and the second stainless steel grid plate blank; S7, spot welding the first stainless steel grid plate blank, the second stainless steel grid plate blank and the connecting flat steel to form a stacked grid assembly stacked up and down; S8, placing the stacked grid assembly horizontally on the support frame; S9. Simultaneously weld the first stainless steel grid plate blank and the second stainless steel grid plate blank on the stacked grid assembly at the same position, first weld the fillet weld between the longitudinal rib plate and the transverse rib plate segment, then weld the fillet weld between the outer circular plate and the longitudinal rib plate, and between the outer circular plate and the transverse rib plate segment; when the tangent angle between the outer circular plate and the longitudinal rib plate and the transverse rib plate is less than 45°, do not weld the fillet weld on that side; use consumable flux-cored wire carbon dioxide gas shielded welding to perform symmetrical welding, vertical welding, continuous welding, single-layer single-pass welding, reflow arc starting, arc closing to fill the arc pit; S10, after being completely cooled, cutting and grinding to remove the spot welding points between the connecting flat steel and the first stainless steel grid plate and the second stainless steel grid plate, so that the spot welding scars on the surface of the longitudinal rib plate are flush with the end surface of the longitudinal rib plate; S11. Inspection after welding.

2. A stainless steel grid plate welding process as claimed in claim 1, characterized in that: In the step S1, each marking line corresponding to the longitudinal rib plate, the outer circular plate, and the transverse rib plate segment in the line drawing includes two rib plate contour lines on both sides and a rib plate center line in the middle.

3. A stainless steel grid plate welding process as claimed in claim 2, characterized in that: The pre-welding preparation in step S2 includes: S21. Qualification check of welders; S22. Test the parent material, welding machine, welding material and shielding gas; S23. Check the dimensions of the outer circular plate, longitudinal rib plate, and transverse rib plate sections.

4. A stainless steel grid plate welding process as claimed in claim 3, characterized in that: In step S32, the outer circular plate, the longitudinal rib plate and the transverse rib plate segments are placed one by one on the stainless steel platform according to the line pattern, and supported by the spot-fixed blocks spot-welded to the stainless steel platform. The specific steps are: S321, first placing the outer circular plate on the marking line corresponding to the scribing pattern; S322, after supporting the outer circular plate with a plurality of spot fixing blocks, spot-welding the spot fixing blocks to the stainless steel platform; S323, placing the longitudinal ribs one by one on the corresponding marks, using the spot fixing block to support each longitudinal rib, and then adjusting the state of the longitudinal ribs to make them perpendicular to the stainless steel platform by measuring with a square, and then spot welding the spot fixing block to the stainless steel platform; S324, after all the longitudinal ribs are placed and assembled, assemble the transverse rib segments in the same manner as in step S323, and the thickness of the spot fixing blocks is 5-8 mm.

5. A stainless steel grid plate welding process as claimed in claim 4, characterized in that: The spot welding sequence of the connecting flat steel in step S7 is: S71, first weld the spot welding points between the connecting flat steel and the longitudinal rib plate near the center, and then weld the spot welding points between the connecting flat steel and the longitudinal rib plate far from the center; S72. When welding each connecting flat steel, spot welding is performed symmetrically from the midpoint of the connecting flat steel to the left and right sides. During spot welding, the spot welding points at the same position of the connecting flat steel and the first stainless steel grid plate blank and the second stainless steel grid plate blank are welded simultaneously by different people; the spot welding points after spot welding are symmetrical with respect to the midpoint of the connecting flat steel; the length of the spot welding is 15-25mm; the welding height is greater than 5mm; the welding procedure regulations for spot welding are the same as the welding procedure regulations for formal welding.

6. A stainless steel grid plate welding process as claimed in claim 5, characterized in that: In step S9, the welding sequence of the fillet weld between the longitudinal rib plate and the transverse rib plate segment is: S91. All longitudinal ribs form a plurality of longitudinal strip grids, and transverse rib plate segments are correspondingly arranged in the longitudinal strip grids; firstly, the transverse rib plate segments in the central longitudinal strip grid are welded, and then the transverse rib plate segments are welded one longitudinal strip grid apart on the left and right sides to implement the first symmetrical jump welding; after the first symmetrical jump welding is completed, the transverse rib plate segments in a longitudinal strip grid on the left or right side of the central longitudinal strip grid are welded, and then the transverse rib plate segments are welded one longitudinal strip grid apart on the left and right sides to implement the second symmetrical jump welding; S92. All transverse rib plate segments within each longitudinal strip grid are diffusion welded from the center to the outside.

7. A stainless steel grid plate welding process as claimed in claim 6, characterized in that: The welding sequence of the fillet welds between the outer circular plate and the longitudinal rib plate, and between the outer circular plate and the transverse rib plate segment in step S9 is: multiple people weld simultaneously in a counterclockwise direction, and the welding positions of multiple people are evenly distributed relative to the central circumference of the stainless steel grid plate blank.

8. A stainless steel grid plate welding process as claimed in claim 7, characterized in that: In step S6, the alignment method between the first stainless steel grid plate blank and the second stainless steel grid plate blank is: positioning is performed using at least one pair of transverse positioning blocks and at least one pair of longitudinal positioning blocks; the transverse positioning blocks are spot welded on the stainless steel platform to position and cooperate with the two side surfaces of one of the transverse rib plate segments, and the longitudinal positioning blocks are spot welded on the stainless steel platform to position and cooperate with the two side surfaces of one of the longitudinal rib plates, and the heights of the transverse positioning blocks and the longitudinal positioning blocks are greater than the thickness of the first stainless steel grid plate blank.

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