CN113814529B

CN113814529B - Welding method for sealing welding between zirconium alloy pipes and plates

Info

Publication number: CN113814529B
Application number: CN202111009329.0A
Authority: CN
Inventors: 莫其鹏; 银润邦; 奚旭; 张涛; 郑周; 王静鸽
Original assignee: Dongfang Boiler Group Co Ltd
Current assignee: Dongfang Boiler Group Co Ltd
Priority date: 2021-08-31
Filing date: 2021-08-31
Publication date: 2023-04-07
Anticipated expiration: 2041-08-31
Also published as: CN113814529A

Abstract

The invention relates to zirconium alloy seal welding, and discloses a welding method for seal welding between zirconium alloy pipes and plates, which comprises the following steps: processing a seal welding groove on the composite tube plate, processing a groove on the heat exchange tube, wherein the position of the groove is matched with the position of the groove; manufacturing welding wire clamping rings matched with the outer diameter of the heat exchange tube and the size of the groove on the composite tube plate, wherein the manufactured clamping rings are split rings and are used in pairs, one of the two clamping rings is used for placing the groove, and the other clamping ring is used for placing the groove; at least two groups of snap rings are put into the groove in pairs, at least one groove is arranged between each pair of snap rings put in the same group, the manual argon tungsten-arc welding self-melting is adopted, the snap rings are melted in a one-layer welding mode, and the welding of all grooves is completed in batches. The invention only adopts one layer of welding, the clamping ring plays a key role in welding formation during welding, an additional protection device is not needed, and the welding quality is good.

Description

Welding method for sealing welding between zirconium alloy pipe and plate

Technical Field

The invention relates to a zirconium alloy heat exchanger manufacturing, in particular to a welding process for sealing welding between zirconium alloy pipes and plates.

Background

Because zirconium and zirconium alloys have excellent corrosion resistance and can resist corrosion attack by most organic acids, inorganic acids, strong bases and some molten salts, some key components in a corrosive environment can use zirconium materials to prolong the service life. In recent years, zirconium and zirconium alloy thereof are widely applied in the fields of chemical industry and the like, which has very important significance in the aspects of improving product quality, prolonging service life of equipment, reducing energy consumption, reducing cost, preventing pollution, improving labor conditions, improving labor productivity and the like.

At present, zirconium alloy is used more and more widely in heat exchangers, a joint form that a pipe plate is provided with a groove and a heat exchange pipe extends out of the surface of the pipe plate is often adopted in the sealing welding process between a zirconium alloy composite pipe plate and a zirconium alloy heat exchange pipe, the welding mode comprises manual argon arc welding and automatic argon arc welding, the groove form which is most commonly used at present is a V-shaped groove, but in the welding process of the groove, because of continuous welding and multilayer welding, the temperature is overhigh, air is easy to oxidize and discolor the zirconium alloy, the strength and the hardness are increased, and the plasticity and the toughness are reduced, so that the welding quality is seriously influenced.

Zirconium is an element that is chemically more reactive than titanium and is easily contaminated with gases, especially in nitrogen and hydrogen atmospheres. If the interlayer temperature is too high, zirconium can strongly absorb hydrogen to form ZrH ₂ And hydrogen holes are very easily generated. Therefore, the weld protection effect of zirconium alloy is higher than that of titanium and titanium alloy during welding, and various measures during welding are more strict than those of titanium and titanium alloy. For this reason, it is common in the prior art to provide special welding protectors for such welding. For example, a zirconium tube welding protective cover with the publication number of CN203956353U, a zirconium alloy welding tool with the publication number of CN212311215U, and an automatic zirconium heat exchanger tube opening welding protective cover with the publication number of CN 204486985U.

The traditional zirconium alloy seal welding method is multilayer welding, because the interval time of each layer is too short, the zirconium alloy is easy to exceed the temperature, the temperature is too high, and oxygen, nitrogen and hydrogen in the air are easy to enter the zirconium alloy, so that the hidden trouble of welding quality is brought. The special protective cover is used for welding, and the operation is inconvenient.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the welding operation is inconvenient and the hidden quality trouble is large. The invention provides a welding method for sealing welding between zirconium alloy pipes and plates, which is mainly applied to the manufacturing of a zirconium alloy heat exchanger. The inventor notices that the sealing welding quantity of the upper tube plate and the heat exchange tube of the heat exchanger is large, the diameters of the heat exchange tubes are consistent, the cost for processing the welding wire clamp rings in batches is lower, meanwhile, the original multilayer welding efficiency is lower, the quality is not easy to guarantee, and therefore the welding seam is formed by utilizing the double welding wire clamp rings and adopting a one-layer welding mode through manual welding.

The technical scheme adopted by the invention for solving the technical problems is as follows: the welding method for sealing welding between the zirconium alloy pipes and the plates comprises the following steps: processing a sealing welding groove on the plate, processing a groove on the pipe, wherein the position of the groove is matched with the position of the groove; manufacturing welding wire clamping rings matched with the outer diameter of the pipe and the size of the groove on the plate, wherein the manufactured clamping rings are split rings and are used in pairs, one of the two clamping rings is used for placing the groove, and the other clamping ring is used for placing the groove; at least two groups of snap rings are put into the groove in pairs, at least one groove is arranged between each pair of snap rings put in the same group, the manual argon tungsten-arc welding self-melting is adopted, the snap rings are melted in a one-layer welding mode, and the welding of all grooves is completed in batches. The pair of snap rings placed in the same groove includes two turns of welding wire, which is referred to as a double-wire ring in the present invention, and the two split rings included therein are formed by bending the welding wire having the same cross-sectional area and length at the same bending radius, and there is no need to make a special distinction when they are installed before welding, but when they are kneaded into a closed ring after installation, the two snap rings may have the case where their inner diameters are not equal.

During welding, because the cross-sectional area of two silk rings is great, both can adopt the V type groove of U type groove also can adopting present commonly used, welder need not go deep into the groove depths, only need weld at nearly groove surface, it is bigger to weld argon gas concentration at this position, the scope of protection is wider, and the field of vision is wide, argon gas in the welder can spread out when welding like this, the fine molten bath when welding is protected, meanwhile, be convenient for observe the welding condition, in time adjust parameter and gas flow, avoid oxygen and nitrogen, hydrogen gets into zirconium alloy, can form full welding seam after the welding, can improve the welding quality who seals the welding comprehensively, need not increase extra special protection device.

The function of the groove is to position: according to the length that the both ends of pipe stretched out in the drawing, the suitable position processing recess on the excircle of pipe, snap ring card is in the recess to realized the location of snap ring, guaranteed that the snap ring does not drop from the pipe, it should be higher than the groove surface that seals the welding a little to pay close to the recess lateral wall of pipe terminal surface, the position of molten bath is suitable when guaranteeing the welding at back.

The groove is provided with the clamping ring, the clamping ring is melted along with the increase of current during welding, the groove is covered by deposited metal during melting, and the groove is higher than the lowest part of the groove, so that the surface of the groove is covered by the clamping ring after the clamping ring is melted, a sealing effect is achieved, the welding quality is ensured, and meanwhile, the welding angle height of seal welding can be ensured. The other clamping ring of the double-wire ring is clamped into the groove, so that a full welding seam can be formed by enough deposited metal after welding, and the quality of the seal is improved. Two wires are easier to achieve uniform, complete melting than one wire for use with wires having the same cross-sectional area.

The clamping ring is made by cutting off the zirconium alloy welding wire after being bent. In order to control the temperature of the zirconium alloy in welding not to exceed the temperature, a batch welding mode is adopted, adjacent grooves cannot be welded in the same batch in sequence, and in order to ensure that no error occurs, at least one groove is arranged between double-wire rings placed in the same batch.

In conclusion, due to the fact that the clamping rings customized in batches according to the size of the pipe are adopted, only one layer is welded when the zirconium alloy seal is welded, the double-wire rings are added before welding, the double-wire rings play a key role in welding forming during welding, only the protective cover on the welding machine is needed, the protective device does not need to be additionally arranged, and full welding seams can be formed after welding. The method of the present invention is more efficient than the prior art methods because the loops of wire are melted in a one layer weld.

Through a plurality of tests, the difference between the inner diameter of the clamping ring and the outer diameter of the pipe is controlled to be 2-3 mm, the clamping ring can be ensured to be closed smoothly, enough deposited metal is always available in the welding of a single welding line, and the welding quality is favorably ensured.

Through multiple tests, the axial gap between the clamping ring and the bottom of the groove is preferably controlled to be 0.1-0.3 mm, the closer the clamping ring is to the bottom of the groove, the better the clamping ring is, the gap between the grooves can be rapidly filled when the clamping ring is molten, the full welding seam is ensured, and the welding quality is favorably improved.

After multiple tests, the depth of the groove is preferably controlled to be 0.3-0.4 mm, and the width of the groove is preferably controlled to be 0.8-1.2 mm, so that the welding wire clamping ring can be reliably fixed on the pipe.

As mentioned above, the welding method of the invention only adopts one-layer welding, in order to ensure the welding quality, two clamping rings are positioned in the same groove, the arc is firstly started on the clamping ring close to the bottom of the groove, the welding wire starts to melt and then appropriately stays, the molten pool starts to be filled from the bottom of the groove, then the welding gun swings to be close to the other clamping ring, the welding wire starts to melt and appropriately stays for a little time, and the welding is sequentially circulated repeatedly until the groove is welded, so that a complete and full welding seam is formed.

The split ring is made of the welding wire, so that the processing is convenient, the processing cost of the snap ring is reduced, and the snap ring is convenient to place into the groove of the pipe. As mentioned above, to ensure that the whole weld has enough deposited metal from the arc start to the completion of welding, the opening of the snap ring is preferably kneaded to form a closed ring after the snap ring is placed in the groove of the pipe and before the snap ring is placed in the groove: the two ends of the split ring are brought close to each other, manually or with a tool, to be in contact or substantially in contact or slightly overlapping. If the state of the split ring is kept, the opening positions of the two snap rings need to be staggered, the opening positions of the split rings can be manually adjusted after the snap rings are placed and before welding, but if the welding yield is ensured for one time, two or one split ring in the same groove is preferably kneaded into a closed ring, and the snap rings are deformed into welding seams after welding is finished.

When a U-shaped groove is machined, the groove is machined by a tungsten steel ball cutter with matched diameter in one-step machining mode, the groove machining efficiency can be improved, meanwhile, the matching degree of the groove size and the clamping ring can be effectively guaranteed, and the welding quality can be guaranteed.

The invention has the beneficial effects that: adopt the snap ring to accomplish the welding, at first, the snap ring welding wire compares with conventional welding wire, the required deposited metal quantity is unanimous, the cost is unanimous basically, do not need extra expense, but only weld a layer of welding seam, the snap ring that single seal weld groove used is the duplex ring, a snap ring is put into the draw-in groove on the pipe, another snap ring is put into the groove on the board, its cross-sectional area is bigger than conventional welding wire, can fill up the groove rapidly when melting, the temperature can not rise very fast, fine control the temperature, welding quality is good, need not extra protection device, after using the snap ring welding efficiency is high, the compactness can be good, send the silk when not needing the welding, only need the welding wire possess from the fusibility just, and is simple in operation.

Drawings

FIG. 1 is a schematic diagram of a zirconium alloy composite tube plate and a zirconium alloy heat exchange tube structure after a clamping ring is assembled and before welding.

Fig. 2 is a schematic view of a groove formed in a heat exchange tube.

FIG. 3 is a schematic cross-sectional shape of a snap ring.

FIG. 4 is a schematic view of the snap ring in a closed loop state.

FIG. 5 is a schematic view of the snap ring in an open ring shape.

Labeled in the figure as: the heat exchange tube comprises a composite tube plate 1, a heat exchange tube 2, a groove 3, a first clamping ring 4, a second clamping ring 5, a groove 6, a heat exchange tube D, a clamping ring outer diameter D, a clamping ring inner diameter H, an axial gap H, a groove H, a groove B width and an S height difference.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

Examples

As shown in fig. 1 to 5, the welding method for sealing welding between zirconium alloy tubes and plates of the present invention, which takes a zirconium alloy composite tube plate and a zirconium alloy heat exchange tube using a U-shaped groove for sealing welding as an example, includes the following steps.

Firstly, in order to ensure that the size and the plasticity of the snap ring are basically consistent, a zirconium alloy welding wire to be welded is bent and cut to form an open ring, as shown in figure 5, the snap ring is used together with two rings, one snap ring clamps a groove on a heat exchange tube, the other snap ring is clamped on a groove, and the cross section area of the snap ring is larger than that of the welding wire used for welding the conventional zirconium alloy, so that the self-melting welding wire has a melting point which is not higher than that of a base metal during self-melting, good fluidity during welding, good wettability and capability of filling gaps, and excellent processing performance. The inner diameter D of the clamping ring is slightly larger than the outer diameter D of the zirconium alloy heat exchange tube, the clamping ring can be conveniently embedded into the groove, and the difference between the inner diameter D of the clamping ring and the outer diameter D of the heat exchange tube is controlled to be D-D = 2-3 mm. Fig. 1 shows the case that the second snap ring 5 assembled in the groove 6 of the heat exchange tube 2 is closer to the end surface of the heat exchange tube than the first snap ring 4 assembled in the groove 3 on the composite tube plate 1, and the opposite effect can be achieved. Both the two methods can be adopted, and the arrangement position of the groove 6 is required to be adapted to the preset assembly method so as to achieve the effect of accurate size after welding.

Secondly, forming a U-shaped groove 3 required by seal welding on the composite tube plate 1 in a spherical cutter machining mode, wherein the spherical cutter is a milling cutter with a cutting edge similar to a sphere and usually assembled on a milling machine and used for milling various curved surfaces and arc grooves; the material of the spherical cutter for processing the zirconium alloy material is usually ultra-fine tungsten steel, the number of the blades is 2, and the spiral angle is 30 degrees; the diameter of the ball head of the spherical cutter is 2.5-50 mm, so that the spherical cutter is convenient to feed and form at one time.

The third step: as shown in fig. 1 and 2, grooves 6 are machined on the heat exchange tube 2: a groove 6 is formed in the heat exchange tube 2, the depth of the groove 6 is 0.3-0.4 mm, the width of the groove 6 is 1.0mm, the height of the upper portion of the groove 6 after assembly is 1.0mm higher than the surface of a groove, namely the height difference S =1mm.

Fourthly, cleaning before welding: removing oil, rust and water in the welding area, cleaning the welding area and the periphery thereof with a cleaning agent, and drying the welding area and the periphery thereof with a dry air blower after cleaning.

Fifthly, placing a first batch of snap rings, wiping the snap rings with a cleaning agent, clamping the snap rings in the zirconium alloy heat exchange tube 2 and the U-shaped groove 3 of the composite tube plate 1, placing a pair of rings into the zirconium alloy sealing welding groove at intervals of one sealing welding, and placing the first snap ring 4 placed in the groove 3 after being sealed manually or by a tool; the other second snap ring 5 is clamped into the groove 6 of the heat exchange tube 2 and then closed; the axial clearance h between the snap ring and the bottom of the U-shaped groove is adjusted to be 0.1-0.3 mm, the proper clearance enables the snap ring to quickly fill the surrounding clearance after melting, the sequence is 1, 3, 5, 7 and 9 … …, and the axial clearance h sequentially goes downwards;

and sixthly, carrying out self-melting by manual argon tungsten-arc welding, wherein the welding current is 100-200A, the voltage is 14-25V, the argon flow is 10-22L/min, the welding current and the voltage are adjusted according to the observed molten pool condition, swinging is carried out in the welding process, both the two clamping rings are melted, arcing is carried out on the first clamping ring 4, energy is generated instantly after the tungsten electrode is subjected to arcing, the high temperature is reached, the clamping ring and the zirconium alloy tube plate are melted by the high temperature generated by arc drawing at an arc striking point, a high-temperature molten welding pool is formed, and the welding line begins to be solidified after one circle of welding. And (3) sequentially welding the sealing edges with the sequence of 1, 3, 5, 7 and 9 … … until the sealing edges are welded.

Step seven, putting the rest snap rings: after welding is finished, snap rings are sequentially placed into zirconium alloy seal welding grooves with the sequence of 2, 4, 6, 8 and 10 … …, namely batch welding is utilized to prevent local temperature overheating in the welding process from affecting the welding effect.

And step eight, welding by using manual argon tungsten-arc welding, and sequentially welding the sealing openings of 2, 4, 6, 8 and 10 … … until welding is right.

The ninth step: and polishing the welding line to meet the flaw detection requirement.

The tenth step: and (5) flaw detection.

The invention adopts one-layer welding, the temperature before welding is controlled to be more than 20 ℃, and the clamping ring is used and is added with the protection device of the welding machine, so that the clamping ring can play a key role in welding and forming during welding, a molten pool is protected from being influenced by air, oxygen, nitrogen and hydrogen are prevented from entering zirconium alloy, a full welding seam can be formed after welding, and the welding quality can be comprehensively improved. The clamping ring can be made by self or customized outside the commission, and the operation of bending the welding wire belongs to the prior art.

Through the test of the inventor, compared with the prior art, when the method of the embodiment is used for welding, the one-time repair rate (the calculation formula of the one-time repair rate is: repair length/weld length) is reduced to 1% from the original 10%, the quality stability is higher, and the repair rate is lower. The conventional multilayer welding method can only weld the same heat exchanger by two persons at most, and the method can weld the same heat exchanger by four persons at most. However, the method of the present invention has the disadvantages: this fine control action is currently difficult to accomplish with automatic welding machines because of the need to oscillate back and forth between two turns of the wire clamp ring during the welding process.

Claims

1. The welding method for sealing welding between the zirconium alloy pipes and the plates is characterized in that: the method comprises the following steps:

processing a sealing welding groove on the plate, processing a groove on the pipe, wherein the position of the groove is matched with the position of the groove;

manufacturing welding wire clamping rings matched with the outer diameter of the pipe and the size of the groove on the plate, wherein the manufactured clamping rings are split rings and are used in pairs, one of the two clamping rings is used for placing the groove, and the other clamping ring is used for placing the groove;

at least two groups of snap rings are put into the groove in pairs, at least one groove is arranged between each pair of snap rings put in the same group, the manual argon tungsten-arc welding self-melting is adopted, the snap rings are melted in a one-layer welding mode, and the welding of all grooves is completed in batches.

2. The method for welding the seal between the zirconium alloy pipe and the plate as set forth in claim 1, wherein: the difference between the inner diameter D of the snap ring and the outer diameter D of the pipe is controlled to be 2-3 mm.

3. The method for welding the seal between the zirconium alloy pipe and the plate as set forth in claim 1, wherein: controlling the axial clearance h between the snap ring and the bottom of the groove to be 0.1-0.3 mm.

4. The method for welding the seal between the zirconium alloy pipe and the plate as set forth in claim 1, wherein: the depth H of the groove is controlled to be 0.3-0.4 mm, and the width B of the groove is controlled to be 0.8-1.2 mm.

5. The method for welding the seal between the zirconium alloy pipe and the plate as set forth in claim 1, wherein: and (3) preferably starting an arc on the clamping ring close to the bottom of the groove by the two clamping rings in the same groove, properly stopping the welding wire after the welding wire starts to melt, then swinging the welding gun to be close to the other clamping ring, properly stopping the welding wire for a certain time after the welding wire starts to melt, and sequentially and repeatedly circulating until the groove is welded.

6. The method for welding the seal between the zirconium alloy pipe and the plate as set forth in claim 1, wherein: and kneading the opening of the snap ring to form a closed ring after the snap ring is placed in the groove of the pipe and before the snap ring is placed in the groove.

7. The method for welding the seal between the zirconium alloy pipe and the plate as set forth in claim 1, wherein: the sealing welding groove adopts a U-shaped groove which is formed by a tungsten steel ball cutter with matched diameter in an adding mode at one time.

8. The method for welding the seals between the zirconium alloy tubes and the plates according to claim 1, wherein the method comprises the following steps: during welding, the welding current is 100-200A, the voltage is 14-25V, and the argon flow is 10-22L/min.

9. The method for welding the seal between the zirconium alloy pipe and the plate as set forth in claim 1, wherein: the sealing welding groove adopts a V-shaped groove.

10. The method for welding the seal between the zirconium alloy pipe and the plate as set forth in claim 1, wherein: the plate is a composite tube plate of a heat exchanger, and the tube is a heat exchange tube of the heat exchanger.