Mirror surface stainless steel welding arching prevention and mirror surface protection method

Abstract

An anti-arching and mirror surface protection method for mirror surface stainless steel welding comprises the following steps that (1) a mirror surface stainless steel plate is fixed, the mirror surface stainless steel plate is placed on a carbon steel plate, and a mirror surface protection film and a pressing block are sequentially placed on the mirror surface stainless steel plate; the thickness of the mirror surface stainless steel plate is 5-8 mm, and the thickness of the carbon steel plate The carbon steel plate needs to be preheated before welding, and the preheating temperature is 60-100 DEG C; (2) the mirror surface stainless steel plate is welded, and flux-cored wire gas shielded welding is adopted in the welding method; the diameter phi of a welding wire ranges from 1.2 mm to 1.4 mm, the welding current ranges from 180 A to 210 A, the welding voltage ranges from 23 V to 27 V, the welding speed ranges from 200 mm / min to 240 mm / min, and the flow of shielding gas CO2 ranges from 15 ml / min to 20 ml / min; (3) symmetric welding is adopted in the welding sequence; during welding, welding is conducted from the center of a welding seam to the two sides, and welding stopping is conducted at the position 10-50 mm away from the end of the mirror surface stainless steel plate And (3) polishing after welding: polishing the welding burning loss part of the mirror surface stainless steel until the mirror surface state is polished.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a method for preventing bulging and protecting the mirror surface of mirror stainless steel welding. Background Art

[0002] In the field of building steel structure power plants, the welding construction process of mirror stainless steel plates and carbon steel column bottom plates is rarely seen. The existing mirror stainless steel and carbon steel plates are overlapped, requiring the weld between the mirror stainless steel and carbon steel to be welded around, and the mirror surface cannot be damaged. Due to different materials, different physical properties, and different plate thicknesses; when the two are welded, a carbon layer is likely to appear on one side of the mirror stainless steel, thereby reducing corrosion resistance, and may cause deformation, arching, mirror damage and other technical problems.

[0003] Chinese patent publication number CN102773593A discloses a double-sided protection welding process for mirror stainless steel plates, the process steps include (1) grinding the surface of the stainless steel plate to be welded flat and clean; (2) installing a welding device above the welded portion, wherein the welding gun muzzle is facing the welded portion; (3) using high-purity argon gas to protect the front of the welded portion, and at the same time setting a box-shaped protection device on the back of the welded portion, and filling the protection device with high-purity argon gas to protect the back; (4) using the welding gun to weld; (5) after welding, the welded portion is subjected to solution treatment and then cooled. The welding process of the invention uses a box-shaped protection device to also perform argon protection on the back of the mirror stainless steel plate, which is easy to operate and can well ensure the quality of the stainless steel plate. The protection device body can be installed on the back of the stainless steel plate using a suction cup, which is convenient for disassembly and installation, and avoids leaving marks on the back of the stainless steel plate. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preventing mirror stainless steel welding from bulging and protecting the mirror surface, which can effectively avoid the problems of mirror stainless steel bulging deformation, mirror surface state protection, etc., and reduce the welding rework rate, improve the welding qualified rate, and increase the first-time qualified rate from 90% to 98%; because the first-time qualified rate is improved, rework is reduced, and the processing efficiency is improved by about 20%.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A method for preventing bulging and protecting the mirror surface of mirror stainless steel welding, characterized in that it comprises the following steps:

[0007] 1) Pretreatment before welding

[0008] Place the mirror stainless steel plate on the carbon steel plate, and place the mirror protective film and the pressing block on the mirror stainless steel plate in sequence to make the mirror stainless steel plate and the carbon steel plate completely fit together; the thickness of the mirror stainless steel plate is 5-8mm, and the thickness of the carbon steel plate is 25-100mm; the carbon steel plate needs to be preheated before welding, and the preheating temperature is 60-100℃;

[0009] 2) Mirror stainless steel plate welding

[0010] The welding method adopts flux-cored gas shielded welding FCAW, and the joint form is lap fillet weld;

[0011] The welding wire diameter is φ1.2~1.4mm, the welding current is 180~210A, the welding voltage is 23~27V, the welding speed is 200~240mm / min, the protective gas is CO2, and the flow rate is 15~20ml / min;

[0012] The welding sequence is symmetrical. When welding, weld from the center of the weld to both sides, and stop welding 10 to 50 mm away from the end of the mirror stainless steel plate; if the mirror stainless steel plate is rectangular, weld the short side weld first, then the long side weld; remove the pressing block after the weld surface cools to room temperature;

[0013] 3) Polishing after welding: polish the burnt parts of the mirror stainless steel welding until it reaches the mirror surface state.

[0014] Preferably, in step 1), before fixing the mirror stainless steel plate, oil stains and dust are removed from the surface of the carbon steel plate.

[0015] Preferably, in step 1), the mirror protective film is adhered to the surface of the mirror stainless steel plate, and preferably, an acrylic pressure-sensitive adhesive is coated on the mirror protective film.

[0016] Preferably, in step 1), the surface of the carbon steel plate is grinded with a grinding wheel within a range of 30 to 50 mm on both sides of the weld until the carbon steel plate reveals a metallic luster.

[0017] Preferably, the pressing blocks include sleepers and weights.

[0018] The mirror protective film includes masking paper, polyethylene (PE) protective film, polyvinyl chloride (PVC) protective film, polyethylene terephthalate (PET) protective film or polyurethane (PU) protective film.

[0019] Preferably, in step 2), before welding, anti-splash liquid is sprayed on the outer side of the mirror stainless steel plate within 0 to 150 mm from the weld; after welding is completed, wait for the surface of the weld to cool to room temperature, or wait for the range of 0 to 100 mm on both sides of the weld to cool to room temperature, and use a soft cloth to wipe the mirror stainless steel plate to remove the splash liquid.

[0020] Preferably, after the welding in step 2) is completed, the pressing block is removed after the range of 0 to 100 mm on both sides of the weld is cooled to room temperature.

[0021] Preferably, step 3) post-weld polishing is performed to polish the surface unevenness, oxide layer and defects caused by welding burns until a mirror finish is achieved.

[0022] In the method of the present invention:

[0023] The present invention cleans the surface of the carbon steel plate before welding to remove iron corrosion and oil stains, which can greatly reduce the generation of welding cracks and pores; at the same time, the carbon steel plate is preheated to 60-100°C to avoid the influence of internal stress generated by uneven heating and cooling on the deformation of the mirror stainless steel plate.

[0024] Applying a protective film on the mirror stainless steel plate before welding can reduce welding spatter and damage to the mirror surface during production and transportation, and effectively protect the mirror surface condition.

[0025] The present invention places a pressing block on the mirror stainless steel plate and utilizes gravity to make the mirror stainless steel plate and the carbon steel plate fit closely, thereby reducing the internal stress generated by the welding heat cycle, thereby reducing deformation and arching of the mirror stainless steel.

[0026] In the welding process of the present invention, FCAW welding wire gas shielded welding is adopted; the welding wire diameter is φ1.2-1.4 mm, the welding current is 180-220 A, the welding voltage is 23-27 V, the welding speed is 200-240 mm / min, the shielding gas is CO2, and the flow rate is 15-20 ml / min, so that the heat input is controlled within the range of 0.9 kJ / cm-1.2 kJ / cm, and symmetrical welding is adopted. When welding, welding is performed from the center of the weld to both sides, and the welding is stopped at 10-50 mm from the end of the mirror stainless steel plate; it can avoid that excessive heat input causes overheating of the weld and the heat-affected zone, resulting in coarse grains, burning of alloy elements, and reduction of corrosion resistance and mechanical properties of the weld metal, thereby reducing welding defects and arching deformation of the stainless steel plate;

[0027] The pressing block is removed after the surface of the weldment cools to room temperature, or preferably after the welding is completed, the range of 0 to 100 mm on both sides of the weld is cooled to room temperature and the welding stress is fully released.

[0028] It is preferred to use an electric grinder with a louver polishing pad to rough-polish the weld and both sides of the weld. After the surface is smooth, use an electric grinder with a wool wheel polishing pad to fine-polish the mirror stainless steel plate; during the process, use talcum powder or polishing wax to assist until the mirror surface is reached.

[0029] Compared with the prior art, the advantages of the present invention are:

[0030] The welding method disclosed in Chinese patent publication number CN102773593A is MIG solid wire shielded welding, the shielding gas used is high-purity 99.99% argon, the joint form is a butt weld, and a protective device is required on the back side for reverse protection, and solid solution treatment is required after welding. The above welding process uses high-purity argon gas with high cost performance, and the process procedure is relatively complicated, requiring high skills of technicians.

[0031] The mirror stainless steel plate and the carbon steel plate are welded by FCAW flux-cored wire shielded welding, the shielding gas is 99.98% purity carbon dioxide with excellent cost performance, and the joint form is a lap fillet weld; symmetrical welding is adopted, welding from the center of the weld to both sides, end stop welding and other measures, and the pressing method is used to effectively control the arching deformation of the mirror stainless steel and the mirror surface state.

[0032] The present invention places a pressing block on the mirror stainless steel plate and utilizes gravity to make the mirror stainless steel plate and the carbon steel plate fit closely, thereby reducing the internal stress generated by the welding heat cycle, thereby reducing the deformation and arching of the mirror stainless steel plate.

[0033] The present invention has a simple processing method, effectively avoids the problems of mirror stainless steel arching and deformation, mirror surface state protection, etc., reduces the welding rework rate, and improves the welding qualified rate; the first-time qualified rate is increased from 90% to 98%; and because the first-time qualified rate is improved, the rework is reduced, which promotes the processing efficiency to be improved by about 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0035] Figure 2 for Figure 1 A top view of

[0036] Figure 3 Schematic diagram of the welding sequence of the method of the present invention. DETAILED DESCRIPTION

[0037] See also Figure 1 to Figure 3 The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding according to the present invention comprises the following steps:

[0038] 1) Pretreatment before welding

[0039] Place the mirror stainless steel plate 2 on the carbon steel plate 1, and place the mirror protective film 3 and the pressing block 4 on the mirror stainless steel plate 2 in sequence, so that the mirror stainless steel plate 2 and the carbon steel plate 1 are completely attached;

[0040] The mirror stainless steel plate 2 has a thickness of 5 to 8 mm, and the carbon steel plate 1 has a thickness of 25 to 100 mm; the carbon steel plate 2 needs to be preheated before welding, and the preheating temperature is 60 to 100°C;

[0041] 2) Mirror stainless steel plate welding

[0042] The welding method adopts flux-cored gas shielded welding FCAW, and the joint form is lap fillet weld;

[0043] The welding wire diameter is φ1.2~1.4mm, the welding current is 180~210A, the welding voltage is 23~27V, the welding speed is 200~240mm / min, the protective gas is CO2, and the flow rate is 15~20ml / min;

[0044] The welding sequence is symmetrical. When welding, weld from the center of the weld 100 to both sides, and stop welding 10 to 50 mm away from the end of the mirror stainless steel plate 2; if the mirror stainless steel plate 2 is rectangular, weld the short side weld first, then weld the long side weld; remove the pressing block after the surface of the weldment cools to room temperature;

[0045] 3) Polishing after welding: polish the burnt parts of the mirror stainless steel welding until it reaches the mirror surface state.

[0046] Preferably, in step 1), before fixing the mirror stainless steel plate 2, the surface of the carbon steel plate 1 is cleaned of oil and dust.

[0047] Preferably, in step 1), the mirror protective film 3 is adhered to the surface of the mirror stainless steel plate 2 , and preferably, an acrylic pressure-sensitive adhesive is coated on the mirror protective film 3 .

[0048] Preferably, in step 1), the surface of the carbon steel plate 1 is grinded with a grinding wheel within a range of 30 to 50 mm on both sides of the weld until the carbon steel plate 1 reveals a metallic luster.

[0049] Preferably, the pressing block 4 includes a sleeper 41 and a pressing iron 42 .

[0050] The mirror protective film 3 includes masking paper, polyethylene PE protective film, polyvinyl chloride PVC protective film, polyethylene terephthalate PET protective film or polyurethane PU protective film.

[0051] Preferably, in step 2), before welding, anti-splash liquid is sprayed on the outer side of the mirror stainless steel plate 2 within 0 to 150 mm from the weld; after welding is completed, wait for the surface of the weld to cool to room temperature, or wait for the range of 0 to 100 mm on both sides of the weld to cool to room temperature, and use a soft cloth to wipe the mirror stainless steel plate to remove the splash liquid.

[0052] Preferably, after the welding in step 2) is completed, the pressing block is removed after the range of 0 to 100 mm on both sides of the weld is cooled to room temperature.

[0053] Preferably, step 3) post-weld polishing includes using an electric grinder in conjunction with a louver polishing pad to roughly polish the outer surface of the mirror stainless steel plate 2. After the surface is smooth, the mirror stainless steel plate 2 is finely polished using an electric grinder in conjunction with a wool wheel polishing pad; during the process, talcum powder or polishing wax is used to assist until the mirror surface is polished.

[0054] Preferably, in step 3), the uneven surface of the weldment, the oxide layer and defects caused by welding burn are polished until a mirror surface is obtained.

[0055] See also Figure 3 When the mirror stainless steel plate 2 is rectangular, the short side weld is firstly welded, then the long side weld is welded, and finally the fillet weld 101 is performed.

[0056] Example 1

[0057] A method for preventing bulging and protecting the mirror surface of mirror stainless steel welding, comprising the following steps:

[0058] 1) Pretreatment before welding

[0059] Place the mirror stainless steel plate 2 on the carbon steel plate 1, and place the mirror protective film 3 and the pressing block 4 on the mirror stainless steel plate 2 in sequence, so that the mirror stainless steel plate 2 and the carbon steel plate 1 are completely attached; the thickness of the mirror stainless steel plate 2 is 6mm, and the thickness of the carbon steel plate 1 is 60mm; the carbon steel plate 2 needs to be preheated before welding, and the preheating temperature is 60℃;

[0060] 2) Mirror stainless steel plate welding

[0061] The welding method adopts flux-cored gas shielded welding FCAW, the joint form is lap fillet weld; the welding wire diameter is φ1.2mm, the welding current is 180~210A, the welding voltage is 23~27V, the welding speed is 200~240mm / min, the shielding gas is CO2, and the flow rate is 16ml / min;

[0062] The welding sequence is symmetrical. When welding, weld from the center of the weld 100 to both sides, and stop welding 15mm away from the end of the mirror stainless steel plate 2; if the mirror stainless steel plate 2 is rectangular, weld the short side weld first, and then weld the long side weld; remove the pressing block after the surface of the weldment cools to room temperature;

[0063] 3) Polishing after welding: polish the burnt parts of the mirror stainless steel welding until it reaches the mirror surface state.

[0064] Example 2

[0065] A method for preventing bulging and protecting the mirror surface of mirror stainless steel welding, comprising the following steps:

[0066] 1) Pretreatment before welding

[0067] Place the mirror stainless steel plate 2 on the carbon steel plate 1, and place the mirror protective film 3 and the pressing block 4 on the mirror stainless steel plate 2 in sequence, so that the mirror stainless steel plate 2 and the carbon steel plate 1 are completely attached; the thickness of the mirror stainless steel plate 2 is 8mm, and the thickness of the carbon steel plate 1 is 90mm; the carbon steel plate 2 needs to be preheated before welding, and the preheating temperature is 90℃;

[0068] 2) Mirror stainless steel plate welding

[0069] The welding method adopts flux-cored gas shielded welding FCAW, the joint form is overlapping fillet weld; the welding wire diameter is φ1.4mm, the welding current is 180~210A, the welding voltage is 23~27V, the welding speed is 200~240mm / min, the shielding gas is CO2, and the flow rate is 15~20ml / min;

[0070] The welding sequence adopts symmetrical welding. When welding, weld from the center of the weld 100 to both sides, and stop welding 40mm away from the end of the mirror stainless steel plate 2; if the mirror stainless steel plate 2 is a rectangle, weld the short side weld first, and then weld the long side weld; remove the pressing block after the surface of the weldment cools to room temperature;

[0071] 3) Polishing after welding: polish the burnt parts of the mirror stainless steel welding until it reaches the mirror surface state.

Claims

1. A method for preventing bulging and protecting the mirror surface of mirror stainless steel welding, characterized in that: The steps include: 1) Pretreatment before welding Place the mirror stainless steel plate on the carbon steel plate, and place the mirror protective film and the pressing block on the mirror stainless steel plate in sequence to make the mirror stainless steel plate and the carbon steel plate completely fit together; the thickness of the mirror stainless steel plate is 5-8mm, and the thickness of the carbon steel plate is 25-100mm; the carbon steel plate needs to be preheated before welding, and the preheating temperature is 60-100℃; 2) Mirror stainless steel plate welding The welding method adopts flux-cored gas shielded welding FCAW, the joint form is overlapping fillet weld; the wire diameter is φ1.2~1.4mm, the welding current is 180~210A, the welding voltage is 23~27V, the welding speed is 200~240mm / min, the shielding gas is CO2, and the flow rate is 15~20ml / min; The welding sequence is symmetrical. When welding, weld from the center of the weld to both sides, and stop welding 10 to 50 mm away from the end of the mirror stainless steel plate. If the mirror stainless steel plate is rectangular, weld the short side weld first, then the long side weld, and finally perform fillet welding. After the surface of the weldment cools to room temperature, remove the pressing block; 3) Polishing after welding: polish the burnt parts of the mirror stainless steel welding until it reaches the mirror surface state.

2. The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding as claimed in claim 1, characterized in that: Step 1) Before fixing the mirror stainless steel plate, remove rust, oil stains and dust from the surface of the carbon steel plate.

3. The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding according to claim 1 or 2, characterized in that: Step 1) sticking a mirror protective film to the surface of the mirror stainless steel plate, preferably using an acrylic pressure-sensitive adhesive to coat the mirror protective film.

4. The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding as claimed in claim 1, 2 or 3, characterized in that: Step 1) Use a grinding wheel to grind the carbon steel plate surface within 30 to 50 mm on both sides of the weld until the carbon steel plate reveals its metallic luster.

5. The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding as claimed in claim 1, characterized in that: The pressing blocks include sleepers and pressing irons.

6. The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding as claimed in claim 1, characterized in that: The mirror protective film includes masking paper, polyethylene protective film, polyvinyl chloride protective film, polyethylene terephthalate protective film or polyurethane protective film.

7. The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding as claimed in claim 1, characterized in that: Step 2) After welding is completed, wait for the area within 0 to 100 mm on both sides of the weld to cool to room temperature and remove the pressing block.

8. The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding as claimed in claim 1, characterized in that: Step 3) post-weld polishing, including using an electric grinder with a louver polishing pad to roughly polish the mirror-finished stainless steel weld and edges. After the surface is smooth, use an electric grinder with a wool wheel polishing pad to finely polish the mirror-finished stainless steel weld and edges; during the process, talcum powder or polishing wax is used to assist until the mirror surface is reached.

9. The method for preventing bulging and protecting the mirror surface of mirror stainless steel welding as claimed in claim 1 or 8, characterized in that: Step 3) Polish the surface unevenness, oxide layer and defects caused by welding burns until they are polished to a mirror finish.

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