A device and process for preventing weld cracking in welded pipe

Abstract

The present application relates to a kind of device and process for preventing weld pipe weld cracking, the anti-cracking pipe body of the device is used to enter weld pipe and carry out cooling temperature reduction;The wind cooling cavity is arranged on the wind cooling pipe body side wall of the one end of anti-cracking pipe body, cooling air is evenly shunted to each air nozzle through the wind cooling cavity, the cooling air with temperature of 80 DEG C ~ 90 DEG C and wind pressure of 0.4MPa ~ 0.6MPa is blown out by air nozzle, and the weld of weld pipe is cooled and temperature reduced, the water cooling chamber is arranged on the water cooling ring side wall of the other end of anti-cracking pipe body, cooling water is evenly shunted to each water nozzle through water cooling chamber, and the cooling water with temperature of 20 DEG C ~ 40 DEG C is sprayed out by water nozzle, and the weld of weld pipe is again cooled and temperature reduced, the device effectively improves the metal crystal organization after welding of weld, micro-crack does not appear at weld, and the problem that weld cracking does not appear when subsequent roll-pressing groove on the end of weld pipe, product quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of welded pipe production and manufacturing, in particular to a device and process for preventing welded pipe weld cracking. BACKGROUND

[0002] Currently, hot-dip galvanized welded pipes have occupied a dominant position in the application of civil building water supply and drainage engineering. In the construction process, in order to facilitate installation, a pipe connection method of clamp type (also known as groove type) is usually used, that is, a certain depth of groove is first rolled and pressed on the outer circle of the two end portions of the hot-dip galvanized welded pipe by using a rolling groove machine, and then a clamp piece with a sealing rubber ring is clamped into the groove between the two hot-dip galvanized welded pipes,

[0003] The two hot-dip galvanized welded pipes are tightly connected together. Compared with the threaded or flange coupling method, this installation method saves the steps of processing threads and welding flanges, and has the advantages of simple operation, fast installation speed, unaffected mechanical properties of hot-dip galvanized welded pipe material, construction safety and environmental protection, stable pipe system, and convenient maintenance, etc., and has become the preferred method for connecting liquid, gas and other conveying pipes.

[0004] The current hot-dip galvanized welded pipe manufacturing process is as follows: strip steel → flattening and conveying → roll forming → high-frequency welding → water cooling → sawing → straightening → milling flat head → hot-dip galvanizing → rolling groove → quality inspection → packaging. In the process of the above-mentioned hot-dip galvanized welded pipe process, after high-frequency high-temperature welding of the welded pipe before hot-dip galvanizing, low-temperature cooling water is directly sprayed on the high-temperature weld area for cooling after welding to prepare for the next process. This water cooling process and method will cause some differences in mechanical properties between the weld material organization and the pipe body material organization, thereby causing micro-cracks at the junction between the welded pipe steel matrix and the weld metal organization. When the hot-dip galvanized welded pipe is subjected to the rolling groove process, the end portion of the hot-dip galvanized welded pipe will be subjected to intense rolling pressure, which is prone to cause cracks or even cracking at the weld, and is prone to cause safety hazards such as water leakage and gas leakage during use. In recent years, hot-dip galvanized welded pipe cracking caused by rolling groove processing has been common, which has brought users unnecessary economic losses and serious consequences. The above-mentioned problems are one of the technical problems that hot-dip galvanized welded pipe manufacturing enterprises urgently need to solve, but so far there is no effective method to solve the problem of weld cracking caused by rolling groove. SUMMARY

[0005] In order to solve the above-mentioned problems, the present application provides a device and process for preventing welded pipe weld cracking.

[0006] The technical scheme of the present application is: a device for preventing weld cracking of welded pipe, comprising an anti-cracking pipe body, an air-cooled pipe body and a plurality of water cooling rings; the anti-cracking pipe body is a circular pipe, the air-cooled pipe body is coaxially connected to one end of the anti-cracking pipe body, the side wall of the air-cooled pipe body is a hollow structure to form an air-cooled chamber, the inner side of the air-cooled pipe body is uniformly provided with a plurality of air nozzles in communication with the air-cooled chamber, and each end of the air-cooled chamber is provided with an air inlet; a plurality of water cooling rings are coaxially connected to the other end of the anti-cracking pipe body, the side wall of the water cooling ring is a hollow structure to form a water-cooled chamber, the inner side of the water cooling ring is uniformly provided with a plurality of water nozzles in communication with the water-cooled chamber along the circumferential direction, and the middle of the water cooling ring is provided with a water inlet.

[0007] Preferably, the spacing between the plurality of water cooling rings is the same.

[0008] Preferably, the lower end of the anti-cracking pipe body is provided with a plurality of cooling water outlets along the radial direction, and the plurality of cooling water outlets are respectively located between the plurality of water cooling rings.

[0009] Preferably, the upper end of the anti-cracking pipe body is provided with a plurality of water vapor outlets, and the plurality of water vapor outlets are respectively located between the plurality of water cooling rings.

[0010] Preferably, the diameter of the air nozzle and the diameter of the water nozzle are both 8mm-10mm.

[0011] A process for preventing weld cracking of welded pipe, characterized by the following steps:

[0012] Firstly, an anti-cracking pipe body, an air-cooled pipe body and a plurality of water cooling rings are made, the anti-cracking pipe body is a circular pipe, the air-cooled pipe body is coaxially connected to one end of the anti-cracking pipe body, the side wall of the air-cooled pipe body is a hollow structure to form an air-cooled chamber, the inner side of the air-cooled pipe body is uniformly provided with a plurality of air nozzles in communication with the air-cooled chamber, and each end of the air-cooled chamber is provided with an air inlet, a plurality of water cooling rings are coaxially connected to the other end of the anti-cracking pipe body at equal intervals, the side wall of the water cooling ring is a hollow structure to form a water-cooled chamber, the inner side of the water cooling ring is uniformly provided with a plurality of water nozzles in communication with the water-cooled chamber along the circumferential direction, and the middle of the water cooling ring is provided with a water inlet; and a plurality of cooling water outlets are provided on the lower end of the anti-cracking pipe body along the radial direction, and the plurality of cooling water outlets are respectively located between the plurality of water cooling rings, and a plurality of water vapor outlets are provided on the upper end of the anti-cracking pipe body, and the plurality of water vapor outlets are respectively located between the plurality of water cooling rings;

[0013] Secondly, cooling air with a temperature of 80-90℃ and a wind pressure of 0.4-0.6MPa is introduced into the air-cooled chamber of the air-cooled pipe body from the air inlet, and the cooling air is uniformly blown into the anti-cracking pipe body from the air nozzles.

[0014] Third step, the cooling water with temperature of 20-40 DEG C is introduced into the water cooling chamber of each water cooling ring from the water inlet, and the cooling water is uniformly sprayed into the anti-cracking pipe body from the water nozzle;

[0015] Fourth step, the welded pipe with welded seam is firstly advanced by 70-80 cm, and after the temperature of the welded seam is naturally decreased to 800-900 DEG C, the welded pipe is coaxially introduced into the anti-cracking pipe body, and when the pipe body is cooled by the wind, the cooling wind blows to the welded seam with temperature of 800-900 DEG C to cool and the wind cooling time is 5-8 s;

[0016] Fifth step, the welded pipe continuously advances in the anti-cracking pipe body, and the cooling water is sprayed to the welded seam cooled by the wind when the pipe body passes through the water cooling ring, and the water cooling time is 10-15 s;

[0017] Sixth step, a large amount of water vapor is generated during the water cooling of the welded pipe, and the water vapor is discharged from each water vapor outlet in time, and the cooling water is discharged from each cooling water outlet in time.

[0018] The beneficial technical effects of the present application are:

[0019] (1) The anti-cracking pipe body of the device for preventing the welded pipe from cracking is used for cooling and cooling the welded pipe, the side wall of the wind cooling pipe body at one end of the anti-cracking pipe body is provided with a wind cooling chamber, the cooling wind is uniformly distributed to each air nozzle through the wind cooling chamber, the cooling wind blown by the air nozzle preliminarily cools and cools the welded seam of the welded pipe, the side wall of the water cooling ring at the other end of the anti-cracking pipe body is provided with a water cooling chamber, the cooling water is uniformly distributed to each water nozzle through the water cooling chamber, and the cooling water blown by the water nozzle secondarily cools and cools the welded seam of the welded pipe. The device integrates the wind cooling and water cooling, realizes the step-by-step cooling and cooling of the welded seam of the welded pipe, and can effectively avoid the problem of welded seam cracking caused by rapid cooling.

[0020] (2) The process for preventing the welded pipe from cracking cools the welded seam in three steps, first, the welded seam of the welded pipe is naturally cooled to 800-900 DEG C, then the welded seam is cooled by the cooling wind with temperature of 80-90 DEG C and wind pressure of 0.4-0.6 MPa, and after the wind cooling, the temperature of the welded seam is reduced to 300-400 DEG C, at this time, the crystal structure of the welded seam tends to be stable, and finally the welded seam is water cooled by the cooling water with temperature of 20-40 DEG C, and after the water cooling, the temperature of the welded seam is reduced to below 100 DEG C; the cooling process can effectively improve the metal crystal structure after welding of the welded seam, and the welded seam will not appear micro-cracks, and the problem of welded seam cracking will not occur when the end of the welded pipe is subsequently rolled and grooved, and the product quality is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic diagram of the three-dimensional structure of the present application;

[0022] Figure 2 is a schematic diagram of the internal structure of the present application;

[0023] Figure 3 is a sectional view along A-A of Figure 2 ;

[0024] Figure 4 is a sectional view along B-B of Figure 2 ;

[0025] Figure 5 is a sectional view along C-C of Figure 2 .

[0026] In the figure, 11. Anti-cracking pipe body, 111. Cooling water outlet, 112. Water vapor outlet, 12. Air-cooled pipe body, 121. Air-cooled chamber, 122. Air nozzle, 123. Air inlet, 13. Water cooling ring, 131. Water-cooled chamber, 132. Water nozzle, 133. Water inlet, 14. Welded pipe, 141. Welding seam. DETAILED DESCRIPTION

[0027] Example one, see the description of the accompanying drawings 1~5, a kind of anti-cracking pipe body, air-cooled pipe body and several water cooling rings are prevented from cracking device of welded pipe welding seam, the outer diameter of welded pipe is less than the inner diameter of anti-cracking pipe body, air-cooled pipe body and water cooling ring;The anti-cracking pipe body is provided as a circular tube, the air-cooled pipe body is coaxially connected to one end of the anti-cracking pipe body, the side wall of the air-cooled pipe body is provided as a hollow structure to form an air-cooled chamber, and the inner side of the air-cooled pipe body is uniformly arranged with a plurality of air nozzles in communication with the air-cooled chamber, so that the cooling air is uniformly distributed to each air nozzle through the air-cooled chamber, so that the wind pressure of the cooling air blown out by each air nozzle is the same. The uniformly arranged air nozzles not only can air-cooled cooling for the welding seam of the welded pipe, but also can air-cooled cooling for the pipe wall outside the welding seam, and each of the two ends of the air-cooled chamber is provided with an air inlet, and a plurality of water cooling rings are coaxially connected to the other end of the anti-cracking pipe body, the side wall of the water cooling ring is provided as a hollow structure to form a water-cooled chamber, and the inner side of the water cooling ring is uniformly distributed with a plurality of water nozzles in communication with the water-cooled chamber along the circumferential direction. Through the water-cooled chamber, cooling water is uniformly distributed to each water nozzle, and the plurality of water nozzles uniformly distributed along the circumferential direction not only can spray cooling for the welding seam of the welded pipe, but also can spray cooling for the pipe wall outside the welding seam, and the middle of the water cooling ring is provided with a water inlet.

[0028] The spacing between the plurality of water cooling rings is the same, and the welded pipe can sequentially pass through each water cooling ring for step-by-step water cooling.

[0029] The lower end side wall of the anti-cracking pipe body is provided with a plurality of cooling water outlets in the radial direction, and the plurality of cooling water outlets are respectively located between the plurality of water cooling rings. The upper end side wall of the anti-cracking pipe body is provided with a plurality of water vapor outlets, and the plurality of water vapor outlets are respectively located between the plurality of water cooling rings. The welded pipe body has a relatively high temperature after air cooling, so a large amount of water vapor will be generated during water cooling. The water vapor outlet can timely discharge the generated water vapor. The cooling water outlet can timely discharge the cooling water from the anti-cracking pipe body, reduce the residence time of water vapor and cooling water in the anti-cracking pipe body, avoid rust on the surface of the welded pipe, and ensure the smooth progress of the subsequent process.

[0030] The diameter of the air nozzle and the diameter of the water spraying nozzle are both 8 mm to 10 mm.

[0031] Embodiment two, see the description of the accompanying drawings Figures 1-5 A process for preventing the weld of a welded pipe from cracking, comprising the following steps:

[0032] First step, make an anti-cracking pipe body, an air cooling pipe body and a plurality of water cooling rings. The anti-cracking pipe body is a circular pipe. The air cooling pipe body is coaxially connected to one end of the anti-cracking pipe body. The side wall of the air cooling pipe body is a hollow structure to form an air cooling chamber. The inner side of the air cooling pipe body is uniformly provided with a plurality of air nozzles in communication with the air cooling chamber. Each end of the air cooling chamber is provided with an air inlet. The plurality of water cooling rings are equally spaced and coaxially connected to the other end of the anti-cracking pipe body. The side wall of the water cooling ring is a hollow structure to form a water cooling chamber. The inner side of the water cooling ring is uniformly provided with a plurality of water spraying nozzles in communication with the water cooling chamber. The middle of the water cooling ring is provided with a water inlet. A plurality of cooling water outlets are provided on the lower end side wall of the anti-cracking pipe body in the radial direction, and the plurality of cooling water outlets are respectively located between the plurality of water cooling rings. A plurality of water vapor outlets are provided on the upper end side wall of the anti-cracking pipe body, and the plurality of water vapor outlets are respectively located between the plurality of water cooling rings.

[0033] Second step, introduce cooling air with a temperature of 80℃ to 90℃ and a wind pressure of 0.4MPa to 0.6MPa into the air cooling chamber of the air cooling pipe body from the air inlet. The cooling air is uniformly blown into the anti-cracking pipe body from each air nozzle.

[0034] Third step, introduce cooling water with a temperature of 20℃ to 40℃ into the water cooling chamber of each water cooling ring from the water inlet. The cooling water is uniformly sprayed into the anti-cracking pipe body from the water spraying nozzle.

[0035] Fourth step, the welded pipe with welded seam is first advanced 70cm~80cm, and after the temperature of the welded seam is naturally decreased from 1250℃~1460℃ to 800℃~900℃, the welded pipe is coaxially entered into the anti-cracking pipe body, and when the pipe body is cooled by air, the cooling air is blown to the welded seam with temperature of 800℃~900℃ for air cooling for 5s~8s; through the step, the temperature of the welded seam is slowly decreased to 300℃~400℃, and the crystal structure of the welded seam tends to be stable;

[0036] The welding of the welded seam of the welded pipe adopts the welding mode of high-frequency inductor, and the welding mode is that an electromagnetic induction loop is formed between the edge of the pipe blank welded seam and the magnetic bar (impedance), the proximity effect is generated, the eddy current heat is concentrated near the edge of the pipe blank, the edge of the pipe blank is heated to the welding temperature, the V-shaped opening position of the welded pipe is generated with high temperature of 1250℃~1460℃, the steel base of the V-shaped opening position of the welded pipe is formed in molten state, and the welded seam is formed under external pressure, the welding mode is a commonly used welding technology in the industry, and will not be described in detail.

[0037] Fifth step, the welded pipe continues to advance in the anti-cracking pipe body, and sequentially passes through a plurality of water cooling rings, the cooling water is sprayed to the welded seam cooled by air, the water cooling time is 10s~15s, and the welded pipe is rapidly cooled through the step; then, sawing, straightening, milling, hot galvanizing, groove rolling and other processes are carried out.

[0038] Sixth step, a large amount of water vapor is generated during the water cooling of the welded pipe, the water vapor is discharged upward from each water vapor outlet in time, and the cooling water is discharged downward from each cooling water outlet in time.

Claims

1. A device for preventing cracking of a welded pipe weld, characterized in that: it comprises an anti-cracking pipe body, an air-cooled pipe body and a plurality of water cooling rings; the anti-cracking pipe body is a circular pipe, the air-cooled pipe body is coaxially connected to one end of the anti-cracking pipe body, the side wall of the air-cooled pipe body is a hollow structure to form an air-cooled chamber, the inner side of the air-cooled pipe body is uniformly provided with a plurality of air nozzles in communication with the air-cooled chamber, and each end of the air-cooled chamber is provided with an air inlet; the plurality of water cooling rings are coaxially connected to the other end of the anti-cracking pipe body, the side wall of the water cooling ring is a hollow structure to form a water-cooled chamber, the inner side of the water cooling ring is uniformly provided with a plurality of water spray nozzles in communication with the water-cooled chamber along the circumferential direction, and the middle of the water cooling ring is provided with a water inlet; the lower end of the anti-cracking pipe body is provided with a plurality of cooling water outlets along the radial direction, and the plurality of cooling water outlets are respectively located between the plurality of water cooling rings; the upper end of the anti-cracking pipe body is provided with a plurality of water vapor outlets, and the plurality of water vapor outlets are respectively located between the plurality of water cooling rings. The spacing between the plurality of water cooling rings is the same. The diameter of the air nozzle and the diameter of the water spray nozzle are both 8mm-10mm. The device is characterized by the following steps:

2. A device for preventing cracking of a weld of a welded pipe according to claim 1, characterized in that: First step, make an anti-cracking pipe body, an air-cooled pipe body and a plurality of water cooling rings, the anti-cracking pipe body is a circular pipe, the air-cooled pipe body is coaxially connected to one end of the anti-cracking pipe body, the side wall of the air-cooled pipe body is a hollow structure to form an air-cooled chamber, the inner side of the air-cooled pipe body is uniformly provided with a plurality of air nozzles in communication with the air-cooled chamber, and each end of the air-cooled chamber is provided with an air inlet, the plurality of water cooling rings are coaxially connected to the other end of the anti-cracking pipe body at equal intervals, the side wall of the water cooling ring is a hollow structure to form a water-cooled chamber, the inner side of the water cooling ring is uniformly provided with a plurality of water spray nozzles in communication with the water-cooled chamber along the circumferential direction, and the middle of the water cooling ring is provided with a water inlet; the lower end of the anti-cracking pipe body is provided with a plurality of cooling water outlets along the radial direction, and the plurality of cooling water outlets are respectively located between the plurality of water cooling rings; the upper end of the anti-cracking pipe body is provided with a plurality of water vapor outlets, and the plurality of water vapor outlets are respectively located between the plurality of water cooling rings.

3. A device for preventing cracking of a weld of a welded pipe according to claim 1, characterized in that: Second step, introduce cooling air with a temperature of 80℃-90℃ and a wind pressure of 0.4MPa-0.6MPa into the air-cooled chamber of the air-cooled pipe body from the air inlet, and the cooling air is uniformly blown into the anti-cracking pipe body from each air nozzle.

4. A process for preventing cracking of a weld seam of a welded pipe, Third step, introduce cooling water with a temperature of 20℃-40℃ into the water-cooled chamber of each water cooling ring from the water inlet, and the cooling water is uniformly sprayed into the anti-cracking pipe body from the water spray nozzle. Fourth step, the welded pipe with welded seam is first advanced by 70cm-80cm, and then the temperature of the welded seam is naturally reduced to 800℃-900℃ from 1250℃-1460℃, and then the welded pipe is coaxially inserted into the anti-cracking pipe body, and when passing through the air-cooled pipe body, the cooling air is blown to the welded seam with a temperature of 800℃-900℃ for air cooling, and the air cooling time is 5s-8s. Fifth step, the welded pipe continues to advance in the anti-cracking pipe body, and when passing through the plurality of water cooling rings in turn, the cooling water is sprayed to the welded seam after air cooling, and the water cooling time is 10s-15s. ​ ​ ​ Sixth, the pipe welding process will produce a large amount of water vapor, water vapor from each water vapor outlet timely discharge, the cooling water from each cooling water outlet timely discharge.

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