Composite board rolled cylinder and preparation method thereof

Abstract

The invention discloses a composite board rolled cylinder and a preparation method thereof. Comprising the following steps of (1) material picking and scribing, (2) blanking, (3) groove machining, (4) rust and oil removal, (5) barrel rolling, (6) longitudinal welding seam assembling, (7) base layer welding seam welding of a base layer part, (8) barrel roundness correction, (9) base layer welding seam groove grinding, (10) transition layer welding seam welding and composite layer welding seam welding of a composite layer and # imgabs0 nondestructive testing. As the ductility of the stainless steel clad layer is stronger than that of a carbon steel plate, the original step (7) of longitudinal weld welding is divided into two steps before and after the step (8) of cylinder roundness correction in the welding process, and after the step (7) of longitudinal weld welding is completed, when the step (8) of cylinder roundness correction is carried out, the stainless steel clad layer is not welded; and a larger extension space is provided in the plate rolling process, the phenomena of multi-layer breakage, separation of a base layer and the multi-layer, weld joint cracking and the like caused by extension extrusion are avoided, the scrap probability of the composite plate is reduced, and high practicability is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite plate tank and tower production technology, and specifically relates to a composite plate rolled cylinder and a preparation method, in particular to a welding method for a carbon steel-stainless steel composite plate structure cylinder or tower. Background Art

[0002] At present, many corrosive media equipment basically adopts carbon steel-titanium composite plates, carbon steel-stainless steel composite plates and other materials, which can increase the service life of the equipment, especially the carbon steel-stainless steel composite plate structure cylinder or tower body is more common.

[0003] In the process of rolling the composite plate cylinder, the commonly used process route is as follows: ① Material marking-② Material cutting-③ Bevel processing-④ Rust removal and oil removal-⑤ Rolling the cylinder-⑥ Assembling longitudinal welds-⑦ Welding longitudinal welds (base layer, transition layer, composite layer) according to the welding process-⑧ Cylinder roundness calibration-⑨ Non-destructive testing. Among them, after the completion of step ⑦, during the operation of step ⑧, due to the different materials and ductility of the composite layer such as stainless steel or titanium, carbon steel plate and the base layer (the ductility of stainless steel plate is greater than that of carbon steel plate), the extension length of the base layer and the composite layer is often different, resulting in composite layer fracture, separation of the base layer and the composite layer, weld cracking and other phenomena. Summary of the invention

[0004] The present invention aims to provide a composite plate rolled cylinder and a preparation method, which avoids the occurrence of composite layer breakage, separation of the base and the composite layer, weld cracking and the like caused by extension and extrusion of the base and the composite layer due to different extension lengths.

[0005] Specifically, the technical solution of the present invention is as follows:

[0006] A method for preparing a composite plate rolled cylinder, comprising the following steps: ① material marking - ② material cutting - ③ groove processing - ④ rust removal and degreasing - ⑤ cylinder rolling - ⑥ assembly of longitudinal welds - ⑦ welding of base welds of base part - ⑧ cylinder rounding - ⑨ grinding of base weld groove - ⑩ welding of transition layer welds and composite layer welds - Non-destructive testing.

[0007] In one embodiment of the present invention, after the ovality of the cylinder body reaches the standard, the base weld groove is ground so that the groove angle reaches 55°±5° before the cylinder body is rounded.

[0008] In one embodiment of the present invention, the base weld is welded while ensuring the misalignment amount and edge angle, and the welding is stopped when the distance from the composite layer is 1.5-2.5 mm.

[0009] In one embodiment of the present invention, when welding the base weld, the misalignment amount b is less than or equal to 50% of the base thickness and less than or equal to 2 mm, and the edge angle E is less than or equal to (plate thickness / 10+2) mm and less than or equal to 5 mm.

[0010] In one embodiment of the present invention, the groove at the base layer and the groove at the composite layer are regular or irregular structures.

[0011] In one embodiment of the present invention, a transition electrode is used to fill the transition weld when welding the longitudinal weld.

[0012] In one embodiment of the present invention, the material of the base layer is carbon steel, and the material of the composite layer is stainless steel.

[0013] The present invention also provides a composite plate rolled cylinder, which is obtained by using the above-mentioned method for preparing the composite plate rolled cylinder.

[0014] The weld portion of the composite plate rolled cylinder includes a base weld between adjacent base layers (such as a carbon steel portion), a composite layer weld between two adjacent composite layers (such as a stainless steel weld portion), and a transition weld between a base weld and a non-composite layer weld.

[0015] Beneficial effects of the present invention:

[0016] Since the ductility of the stainless steel clad layer is stronger than that of the carbon steel plate, the present invention divides the original step ⑦ welding the longitudinal weld into two steps during the welding process and places them respectively before and after the step ⑧ cylinder rounding. In this way, after the base layer of the step ⑦ welding the longitudinal weld is completed, when the step ⑧ cylinder rounding is performed, the stainless steel clad layer is not welded, which provides a larger extension space for it during the rolling process, avoids the phenomenon of clad layer breakage, separation of the base layer and clad layer, weld cracking, etc. due to extension and extrusion, reduces the probability of scrapping the composite plate, and has strong practicality.

[0017] After step ⑧ is completed, proceed to step ⑨ to grind the base weld groove and step ⑩ to weld the transition layer and complex layer of the longitudinal weld. The purpose of grinding the base weld groove is to make it consistent with the size of the electrode, because the longitudinal seam and circumferential seam must be fully penetrated and welded. If the groove is too small or irregular, the electrode cannot be inserted or the weld is prone to pores. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the weld seam before cylinder rounding of the composite plate rolled cylinder (also the weld seam after the base weld seam groove is ground after cylinder rounding);

[0019] Figure 2 This is a schematic diagram of the weld structure after the composite plate rolled cylinder is rounded and the base layer is extended;

[0020] Figure 3It is a schematic diagram of the structure after the weld seam of the composite plate rolled cylinder is welded;

[0021] Figure 4 Schematic diagram of the structure of the separation of the base layer and the composite layer of the composite plate. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be emphasized that the specific embodiments described herein are only used to better illustrate the present invention, are some embodiments of the present invention, not all embodiments, and are not used to limit the present invention. In addition, the technical features involved in the embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Example 1

[0024] Roll a section of composite plate cylinder, the thickness is S31603+Q345Rδ(5+30), the inner diameter of the cylinder is DN=3000mm, and the length of the cylinder is L=2000mm. The specific operation process is as follows:

[0025] ① Material collection and marking: Collect composite steel plates from the warehouse, layout the composite plates according to the size specifications of the cylinder tower body, and draw the cutting line and 50mm inspection line of the cutting size. The diagonal deviation is ≤2.0mm.

[0026] ②Cutting: Cutting according to the line.

[0027] ③ Groove processing: according to the drawings and welding process cards, use a semi-automatic cutting machine to cut out the required type of groove, which can be a double-sided groove or a single-sided groove. In the present invention, it is a double-sided groove as shown in the figure.

[0028] ④Rust and oil removal: Remove rust, oil and oxides within 35-50mm on the groove surface and on both sides of the weld.

[0029] ⑤Rolling the cylinder: Roll the plate according to the test sample.

[0030] ⑥ For longitudinal welds, when the misalignment b is ≤2mm and the edge angle E (plate thickness / 10+2) is ≤5mm, use carbon steel electrodes to spot weld the fixed points with a length of 10-20mm, a weld height of ≤4mm, a spot welding spacing of 200-300mm, and arc starting plates at both ends of the weld.

[0031] ⑦ Welding the base of the longitudinal weld: According to the welding process, when the longitudinal weld is butt-jointed, the base part must be welded under the premise of ensuring the amount of misalignment and edge angle, and the welding should be stopped when it is 1.5-2.5mm away from the composite layer (such as Figure 1 ).

[0032] Before welding, the main things to do are to grind the angle of the groove and the rust on the weld, so that the groove is regular, the angle is appropriate (if the angle is too small, the welding rod or welding wire cannot be inserted; if the angle is too large, the welding amount is too large, which is labor-intensive and wasteful), and the weld is clean (without rust and oil stains).

[0033] ⑧ Cylinder roundness calibration: After the base welding is completed, the cylinder roundness is calibrated according to the sample. The ovality e≤30mm between the maximum and minimum diameters on the same section.

[0034] ⑨ Grind the weld base groove: After the cylinder ovality meets the standard, the stainless steel cladding is more ductile than the carbon steel base, so the base steel plate at the weld extends more toward the weld, making the groove at the base steel plate at the weld irregular (such as Figure 2 ), grind the groove of the base weld again, and make the groove angle reach the size before the cylinder is rounded (55°±5°) (such as Figure 1 ).

[0035] ⑩ Welding the transition layer of the longitudinal weld: After grinding, use the transition electrode to weld the transition layer weld. The penetration depth of the transition layer in the composite layer is 0.5-1mm. After the transition layer is welded, use a stainless steel electrode to weld the weld at the composite layer.

[0036] Non-destructive testing: Carry out non-destructive testing according to the requirements of the drawings.

[0037] Among them, the strength of the equipment is mainly guaranteed by the base layer of the composite plate. The main function of the composite layer is to contact with the working medium to prevent the working medium from corroding the base layer, and its strengthening effect on the cylinder is minimal.

[0038] The above is only a preferred application implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a composite plate rolled cylinder, characterized in that: The following steps are involved: ① Material marking-② Material cutting-③ Bevel processing-④ Rust removal and degreasing-⑤ Rolling the cylinder-⑥ Assembling the longitudinal welds-⑦ Welding the base welds (3) of the base layer (2)-⑧ Cylinder rounding-⑨ Grinding the base weld groove-⑩ Welding the transition layer welds (4) and the composite layer welds (5) at the composite layer (1)- Non-destructive testing.

2. The preparation method according to claim 1, characterized in that: After the cylinder ovality meets the standard, grind the base weld groove so that the groove angle reaches 55°±5° before the cylinder is rounded.

3. The preparation method according to claim 1, characterized in that: The base weld (3) is welded under the premise of ensuring the misalignment amount and edge angle, and the welding is stopped when the distance from the composite layer (1) is 1.5-2.5 mm.

4. The preparation method according to claim 3, characterized in that: When welding the base weld (3), the misalignment amount b is less than or equal to 50% of the thickness of the base (2) and less than or equal to 2 mm, and the edge angle E is less than or equal to (plate thickness / 10+2) mm and less than or equal to 5 mm.

5. The preparation method according to claim 1, characterized in that: The bevel at the base layer (2) and the bevel at the composite layer (1) are regular or irregular structures.

6. The preparation method according to claim 1, characterized in that: When welding the longitudinal weld, a transition electrode is used to fill the transition weld (4).

7. The preparation method according to claim 1, characterized in that: The material of the base layer (2) is carbon steel, and the material of the composite layer (1) is stainless steel.

8. A composite plate rolling cylinder, characterized in that: The composite plate rolled cylinder is prepared by the method for preparing the composite plate rolled cylinder according to any one of claims 1 to 7.

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