Welding method for class d welded joint of zirconium-titanium steel clad plate equipment

Abstract

The present application relates to the technical field of welding method, in particular to a welding method of D type welding joint of zirconium-titanium steel composite plate equipment, which comprises the following steps: (1) cleaning the surface of the zirconium-titanium steel composite plate pressure vessel shell to remove rust, grease and dust; (2) positioning the shell cleaned in step (1) by spot welding, and then machining the shell to form a hole; (3) welding the shell with a steel connecting pipe, a zirconium lining pipe, a zirconium cover ring and a steel protection pipe after the hole is formed in step (2) to form a welding joint. The present application is characterized in that the zirconium-titanium clad layer of the zirconium-titanium steel composite plate of the shell is not polished and stripped, and the advantage is that there is no polishing operation; that is, the shell steel base layer wall thickness will not be thinned, and there is no need for steel base layer thickness measurement, no need for repair welding and detection due to polishing, and no time-consuming and labor-consuming. Each connecting pipe D type welding joint saves more than half of the processing, manufacturing and detection time compared with the original plug-in type welding joint.

Description

Welding method for Class D welded joints in zirconium-titanium steel composite plate equipment Technical Field

[0001] This invention belongs to the field of welding technology, specifically the research field of welding technology for pressure vessels, and more specifically, the welding method for Class D welded joints of zirconium-titanium steel composite plate equipment. Background Technology

[0002] Zirconium composite plates used in pressure vessels are important chemical equipment widely applied in the chemical industries of hydrogen peroxide, acetic acid, nitric acid, and urea in recent years. Because zirconium cannot be welded to iron-based materials, the material requirements, structural design, manufacturing, and testing of such equipment are quite unique. Commonly used zirconium composite plates are two-layer and three-layer composites. Domestically produced plates are generally three-layer zirconium-titanium steel composite plates, such as Q345R+TA1+R60602, typically with a 3mm zirconium layer and a 2mm titanium layer. For end caps, composite plates are sometimes used with a 4mm zirconium layer and a 2mm titanium layer to account for the thinning during stamping.

[0003] Currently, all Class D welded joints for pressure vessels made of zirconium-titanium steel composite plates on the market are insert-type structures with a double leak-proof design. Due to structural reasons, the welded portion between the steel base layer of the shell composite plate and the steel connecting pipe requires a zirconium filler ring, necessitating the removal of a portion of the zirconium-titanium cladding from the perforated side of the shell composite plate. Since the pressure-bearing shells are all rotating bodies with saddle-shaped perforations, this portion of the zirconium-titanium cladding cannot be machined and must be manually ground using tools such as angle grinders. Manually grinding a 5mm thick zirconium-titanium cladding requires significant time and is extremely difficult to control without damaging the steel base layer. Therefore, the aforementioned Class D joints present high processing costs and uncontrollable manufacturing risks. Thus, it is crucial that the welding method avoids damaging the steel base layer of the shell. Summary of the Invention

[0004] Based on the problems existing in the prior art, this invention proposes a welding method for Class D welded joints in zirconium-titanium steel composite plate equipment, which includes the following steps:

[0005] (1) Clean the surface of the pressure vessel shell made of zirconium-titanium steel composite plate to remove rust, grease and dust;

[0006] (2) The shell cleaned in step (1) is spot welded and positioned, and then the shell is machined to make holes;

[0007] (3) Weld the shell after the hole is opened in step (2) to the steel pipe, zirconium liner, zirconium cap ring and steel protective pipe to form a welded joint.

[0008] Based on the above scheme, the zirconium-titanium steel composite plate pressure vessel shell in step (1) includes a steel base layer, a titanium cladding, and a zirconium cladding arranged in sequence.

[0009] Based on the above scheme, step (2) of machining the shell to create a hole specifically includes:

[0010] The inner holes and leak detection holes of the zirconium-titanium steel composite plate shell are machined using machining methods;

[0011] The leak detection hole is machined to the outer surface of the zirconium cladding, and a zirconium leak detection tube for detecting the presence of helium leaks is installed inside the leak detection hole.

[0012] Based on the above scheme, step (3) of welding the shell after the hole is opened in step (2) to the steel connecting pipe, zirconium liner, zirconium cap ring, and steel protective pipe specifically includes:

[0013] The inner hole and the weld bevel at the end of the steel pipe are machined.

[0014] After the interfaces are properly aligned, the steel base layer of the shell and the steel connecting pipe are welded together to form welded joint one;

[0015] The root of the incomplete weld joint is removed by machining, and the shell and steel pipe are machined to the inner hole size for assembly with the zirconium liner tube.

[0016] Perform 100% MT inspection on the surface of weld joint one;

[0017] Assemble the zirconium liner, weld the zirconium cladding and zirconium liner to form welded joint two;

[0018] The surface of weld joint two was subjected to 100% PT inspection;

[0019] Weld the zirconium leak detection tube and zirconium cladding to form welded joint three;

[0020] The surface of weld joint three was subjected to 100% PT inspection;

[0021] Weld the zirconium cladding and zirconium cap ring to form welded joint four;

[0022] Weld the zirconium cap ring and zirconium liner tube to form welded joint five;

[0023] The surfaces of weld joints four and five were subjected to 100% PT inspection.

[0024] Helium leak testing was performed on weld joints four and five using a zirconium leak detection tube.

[0025] Weld the steel base layer and the steel protective tube used to protect the zirconium leak detection tube to form a welded joint.

[0026] Based on the above scheme, the size of the inner hole of the housing for connecting pipes is: The diameter of the leak detection hole

[0027] Based on the above solution, the inner diameter of the steel pipe is machined.

[0028] Based on the above solution, the shell and steel connecting pipe are machined to the inner hole size for assembly with the zirconium liner tube.

[0029] Compared with existing technologies, the welding method of this invention features a placement-type welded joint (Type D). In this structure, the steel base layer of the shell composite plate, the steel connecting pipe, and their welded joints are in direct contact with the zirconium liner. The zirconium-titanium cladding is directly welded to the zirconium liner, thus eliminating the need to peel off the zirconium-titanium cladding from the shell composite plate. Furthermore, it maintains a double leak-proof structure. In addition, this invention eliminates the need for grinding to peel off the zirconium-titanium cladding from the shell zirconium-titanium steel composite plate, saving labor and time costs associated with grinding, eliminating tool wear, and eliminating grinding operations. This avoids thinning of the shell steel base layer, eliminating the need for steel base layer thickness measurement, and preventing the time-consuming processes of repair welding and inspection due to thinning of the base layer caused by grinding. This achieves excellent manufacturing process results with low labor costs, low time costs, and high quality. The welding method of this invention saves more than half of the processing, manufacturing, and inspection time compared to the original insert-type welded joint. Attached Figure Description

[0030] Figure 1 is a schematic diagram of the D-type welding joint of the zirconium-titanium steel composite plate equipment in this invention;

[0031] Figure 2 is a schematic diagram of the pressure vessel made of zirconium-titanium steel composite plate in this invention before welding. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention and do not constitute any limitation thereof.

[0033] As shown in Figures 1-2, the present invention provides a welding method for Class D welded joints of zirconium-titanium steel composite plate equipment, specifically including the following steps: The welding method of this embodiment is applicable to the welding of DN50-DN600 specification pipes to equipment. The following dimensional data take DN300 specification pipes as an example (steel pipe 14 outer diameter 365mm, zirconium liner 13 outer diameter 313mm).

[0034] All joints connecting the nozzles (including manhole cylinders), flanges, reinforcing rings, etc., to the shell are classified as Class D welded joints.

[0035] I. Preparations before welding

[0036] S1. The inner hole of the zirconium-titanium steel composite plate shell (the shell includes a steel base layer 4, a titanium cladding layer 5, and a zirconium cladding layer 6) is machined using a machining method. The inner diameter of the inner hole (for connecting pipes) is... Diameter of leak detection hole 15

[0037] Specifically, the zirconium-titanium steel composite plate is processed into a zirconium-titanium steel composite plate pressure vessel using a reasonable machining method (selected according to the size of the opening and the wall thickness of the shell); during processing, the cutting temperature is reduced to prevent delamination between the steel base layer 4 and the titanium cladding 5 and spontaneous combustion of the zirconium cladding 6;

[0038] Leak detection holes 15 are machined on the pressure vessel shell of zirconium-titanium steel composite plate. The leak detection holes 15 are machined to the outer surface of zirconium cladding 6. A zirconium leak detection tube 1 is installed in the leak detection hole 15. At this time, the zirconium leak detection tube 1 is used to detect whether there is a helium leak.

[0039] S2. The inner hole of the steel pipe 14 is machined by means of machining, and the diameter of the inner hole is... and the welding bevel at the end (select the corresponding bevel size according to relevant standards).

[0040] II. Welding to form a joint and performing non-destructive testing on the joint.

[0041] S3. After the interface is properly connected, weld the steel base layer 4 of the shell and the steel pipe 14 to form welded joint 12 (before processing).

[0042] S4. Remove the root of the incomplete weld joint 12 by machining, and machine the shell (including the steel base layer 4, titanium cladding 5, and zirconium cladding 6) and the steel pipe 14 to the inner hole size for assembly with the zirconium liner 13; specifically, the inner hole size of the shell and the steel pipe 14 (after welding and machining). (Measured outer diameter of zirconium liner tube 13).

[0043] S5. Perform 100% MT inspection on the surface of welded joint-12 to ensure that the surface of welded joint-12 is free of defects. Specifically, MT: Magnetic Particle Testing is a method of observing defects using magnetic particles as a display medium.

[0044] S6. Assemble the zirconium liner tube 13 and weld the zirconium cladding 6 and the zirconium liner tube 13 to form welded joint 2 11.

[0045] S7. Perform 100% PT inspection on the surface of welded joint 211 to ensure that the surface of welded joint 211 is free of defects.

[0046] Specifically, PT is an abbreviation for penetration testing, also known as penetration testing.

[0047] Penetration testing (PT) is a non-destructive testing method for surfaces and is one of the five conventional non-destructive testing methods.

[0048] Penetrant testing is based on the wetting ability of liquids on solids and capillary action in physics. First, a liquid penetrant containing dye and with high penetrating power is applied to the surface of the workpiece to be tested. Due to the wetting and capillary action of the liquid, the penetrant seeps into the surface opening defects. Then, the excess penetrant on the surface is removed, and a layer of developer with strong adsorption is applied. The penetrant in the defects is adsorbed onto the surface of the workpiece, and the traces of the defects are displayed on the developer.

[0049] S8, weld zirconium leak detection tube 1 and zirconium cladding 6 to form welded joint 38.

[0050] S9. Perform 100% PT inspection on the surface of welded joint 38 to ensure that the surface of welded joint 38 is free of defects.

[0051] Specifically, the PT detection is performed in the same way as step S7.

[0052] S10, weld the zirconium cladding 6 and zirconium cap ring 9 to form welded joint 4 7; weld the zirconium cap ring 9 and zirconium liner tube 13 to form welded joint 5 10.

[0053] S11: Perform 100% PT inspection on the surfaces of weld joint 4.7 and weld joint 5.10 to ensure that the surfaces of weld joint 4.7 and weld joint 5.10 are free of defects. Specifically, the PT inspection is the same as step S7.

[0054] S12: Perform helium leak testing on weld joint 4-7 and weld joint 5-10 using zirconium leak detection tube 1 to ensure that weld joint 4-7 and weld joint 5-10 are leak-free.

[0055] S13: Weld the steel protective pipe 2 and the steel base layer 4 to form a welded joint 3, which is used to protect the zirconium leak detection pipe 1.

[0056] In this invention, the D-type welded joint is a placement structure. After this placement-type pipe structure is implemented on multiple zirconium-titanium steel pressure vessel equipment, each D-type welded joint saves more than half of the processing, manufacturing and testing time compared to the original insertion-type welded joint.

[0057] Specifically, firstly, the steel base layer 4 of the shell composite plate, the steel pipe 14, and their welded joints are in direct contact with the zirconium liner 13; secondly, the titanium cladding 5 and the zirconium cladding 6 are directly welded to the zirconium liner 13, thus eliminating the need to peel off the zirconium-titanium cladding of the shell composite plate; most importantly, this technical solution still provides a double leak-proof structure; in summary, this invention provides a D-type welded joint structure that is easier to process and manufacture, with the advantages of low labor and time costs and easy processing operation, achieving high manufacturability of the D-type welded joint.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A welding method for Class D welded joints of zirconium-titanium steel composite plate equipment, characterized in that, The method includes the following steps: (1) cleaning the surface of the pressure vessel shell of the zirconium-titanium steel composite plate to remove rust, grease and dust; (2) spot welding the shell after cleaning in step (1) and then machining the shell to make holes; (3) welding the shell after the holes are made in step (2) with the steel pipe (14), zirconium liner (13), zirconium cap ring (9) and steel protective pipe (2) to form a welded joint; the zirconium-titanium steel composite plate pressure vessel shell in step (1) includes a steel base layer (4), a titanium cladding (5) and a zirconium cladding (6) arranged in sequence; the step ( Step 2) involves machining the shell to create openings, specifically including: machining the inner hole and leak detection hole (15) of the zirconium-titanium steel composite plate shell; machining the leak detection hole (15) to the outer surface of the zirconium cladding (6), and installing a zirconium leak detection tube (1) for detecting helium leaks inside the leak detection hole (15); Step 3 involves welding the shell after the opening in Step 2 to the steel pipe (14), zirconium liner (13), zirconium cap ring (9), and steel protective pipe (2), specifically including: machining the inner hole and end of the steel pipe (14). The welding bevel of the part is formed; after the interface is properly connected, the steel base layer (4) of the shell and the steel pipe (14) are welded to form weld joint one (12); the root of the incomplete weld joint one (12) is removed by machining, and the shell and the steel pipe (14) are machined to the inner hole size for assembly with the zirconium liner (13); the surface of weld joint one (12) is subjected to 100% MT inspection; the zirconium liner (13) is assembled, and the zirconium cladding (6) and the zirconium liner (13) are welded to form weld joint two (11); the surface of weld joint two (11) is subjected to 100% PT inspection; the zirconium leak detection tube (1) and the zirconium cladding are welded to form weld joint two (11). Layer (6) to form welded joint three (8); perform 100% PT testing on the surface of welded joint three (8); weld zirconium cladding (6) and zirconium cap ring (9) to form welded joint four (7); weld zirconium cap ring (9) and zirconium liner (13) to form welded joint five (10); perform 100% PT testing on the surface of welded joint four (7) and welded joint five (10); perform helium leak testing on welded joint four (7) and welded joint five (10) through zirconium leak detection tube (1); weld steel base layer (4) and steel protective tube (2) for protecting zirconium leak detection tube (1) to form welded joint six (3).

2. The welding method for the Class D welded joint of the zirconium-titanium steel composite plate equipment according to claim 1, characterized in that, The dimensions of the inner bore of the housing used for the pipe connection are: D1 = 303 mm, the diameter of the leak detection hole (15) d=10mm。 3. The welding method for the Class D welded joint of the zirconium-titanium steel composite plate equipment according to claim 1, characterized in that, The inner diameter of the steel pipe (14) is machined. D2=297。 4. The welding method for Class D welded joints of the zirconium-titanium steel composite plate equipment according to claim 1, characterized in that, The shell and steel connecting pipe (14) are machined to the inner diameter size for assembly with the zirconium liner (13). D=313mm。

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