Flexible temperature-controlled heating belt for welding seam and heating method for welding ring weld of box-shaped steel beam

Abstract

The present invention discloses a welding seam flexible temperature control heating belt and a heating method for the ring weld of a box-type steel beam, wherein the welding seam flexible temperature control heating belt comprises an induction heating coil, the induction heating coil is a belt-shaped annular hollow structure, and the induction heating coil is packaged by coating a high-temperature resistant fireproof material; a plurality of permanent magnets are evenly distributed on the high-temperature resistant fireproof material, and the permanent magnets are located on the same side, and a power quick-plug connector is connected to the induction heating coil. The heating belt of the present invention does not generate heat itself, has high safety, does not need to be removed during the welding process, can realize the functions of preheating before welding, heat preservation during welding, and slow cooling after welding, effectively prevents the generation of high-strength steel welding cracks, and ensures the welding quality of the box beam.

Description

Technical Field

[0001] The invention belongs to the technical field of on-site girder welding of high-strength steel box beams, and in particular relates to a welding seam flexible temperature-controlled heating belt and a heating method for the girder welding of box beams. Background Art

[0002] With the needs of modern steel bridge construction, the application of high-strength steel has become more and more extensive, in order to achieve large spans, reduce the cross-section of steel beams, and save steel without significantly increasing the amount of engineering. For example, the Hutong Yangtze River Bridge, which was built in 2016, used 500MPa high-strength steel for the first time; the Wuhan Jianghan Seventh Bridge, which was built in 2018, used 690MPa high-strength steel for the first time. The higher the steel grade, the higher the carbon equivalent, and the worse the weldability. High-strength steel is sensitive to welding preheating temperature and cooling rate, and the probability of welding cracks is very high, especially in high-altitude welding construction on site. In order to ensure the welding quality of steel beams and thick plates on site and implement effective weld crack prevention and crack resistance measures, an efficient preheating and slow cooling device is needed. Summary of the invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a weld flexible temperature control heating belt and a heating method for box-type steel beam ring weld. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0004] A flexible temperature-controlled heating belt for a weld comprises an induction heating coil, which is a belt-shaped annular hollow structure and is encapsulated by coating with a high-temperature resistant and fireproof material; a plurality of permanent magnets are evenly distributed on the high-temperature resistant and fireproof material, and the permanent magnets are located on the same side; and a power quick-plug connector is connected to the induction heating coil.

[0005] Furthermore, the width of the hollow portion is 100-120 mm.

[0006] The present invention also provides a method for heating a box-type steel beam girder ring weld using the weld flexible temperature control heating belt as described in any of the above embodiments, comprising:

[0007] Step 1: Arrange the two heating belts symmetrically on the two symmetrical welding grooves of the box-shaped steel beam, straighten and smooth the heating belts, make the permanent magnets firmly adsorbed to the surface of the box-shaped steel beam, ensure that the center of the hollow part of the heating belt is aligned with the center of the welding groove of the weld, and connect the two heating belts to the electromagnetic induction heater through power quick-plug connectors;

[0008] Step 2: insert two thermocouples respectively between the two heating belts and the surface of the box-shaped steel beam, and connect the two thermocouples to the electromagnetic induction heater respectively, and set the heating temperature on the electromagnetic induction heater;

[0009] Step 3: Start the electromagnetic induction heater, and the two heating belts heat the welding groove at the same time. When the temperature displayed on the electromagnetic induction heater reaches the set heating temperature, use an infrared thermometer to measure the surface temperature of the box-shaped steel beam exposed in the hollow part of the heating belt. When the measured temperature is within 10°C of the temperature displayed on the electromagnetic induction heater, start the welding operation;

[0010] Step 4: After welding is completed, set the cooling time on the electromagnetic induction heater, and the two heating belts slowly cool down at the same time to allow the weld to cool slowly;

[0011] Step 5: Repeat steps 1 to 4 to complete the welding of the other two welding grooves of the box-type steel beam ring weld.

[0012] Furthermore, the cooling time in step 4 is not shorter than the natural cooling time of the box-type steel beam after welding.

[0013] Beneficial effects of the present invention:

[0014] The heating belt of the present invention does not generate heat itself and has high safety. It does not need to be removed during the welding process and can realize the functions of preheating before welding, heat preservation during welding and slow cooling after welding, effectively preventing the occurrence of high-strength steel welding cracks and ensuring the welding quality of steel beams.

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 It is a schematic diagram of the use state of the heating belt of the present invention when it is on the left and right sides of the ring weld of the box-shaped steel beam;

[0018] Figure 3 for Figure 2 A schematic diagram of the enlarged structure of part A;

[0019] Figure 4 for Figure 2 A side view schematic diagram of the structure;

[0020] Figure 5 It is a schematic diagram of the use state of the heating belt of the present invention at the upper and lower ends of the ring weld of the box-type steel beam.

[0021] Description of reference numerals:

[0022] 1-induction heating coil; 2-permanent magnet; 3-power quick-connect connector; 4-induction heater; 5-thermocouple. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0024] Example 1

[0025] See also Figure 1 An embodiment of the present invention provides a flexible temperature-controlled heating belt for a weld, comprising an induction heating coil 1, which is a belt-shaped annular hollow structure, and the induction heating coil 1 is packaged by covering it with a high-temperature resistant fireproof cloth to prevent the induction heating coil from being damaged during use; a plurality of permanent magnets 2 are evenly distributed on the high-temperature resistant fireproof cloth, and the permanent magnets 2 are located on the same side, and a power quick-plug connector 3 is connected to the induction heating coil.

[0026] Furthermore, the induction heating coil 1 is wound into a ring with a width of 150 mm by a cable with a diameter of 8 mm; the induction heating coil 1 is attached to the weldment to be welded through a plurality of permanent magnets 2, and the weld groove is located at the center of the hollow part of the induction heating coil 1; and the interval between two adjacent permanent magnets 2 is 0.5 m, and the suction force of each permanent magnet 2 is not less than 1 kg, so as to ensure the adhesion of the induction heating coil 1 to the surface of the weldment.

[0027] Furthermore, the width of the hollow part of the induction heating coil 1 is 100 mm. The induction heating coil 1 is designed as a hollow structure, and the welding groove is located in the hollow part. The heating belt does not need to be removed during welding.

[0028] Example 2

[0029] See also Figure 2 to Figure 5 Based on Example 1, the present invention provides a method for heating the ring weld of a box-shaped steel beam, wherein a flexible temperature-controlled heating belt for the weld is used in the heating method, which specifically includes the following steps:

[0030] Step 1: According to the welding process requirements, two heating belts are grouped together, and the two heating belts are symmetrically arranged on the two symmetrical welding grooves of the box-shaped steel beam ring weld. The heating belts are straightened and smoothed, so that the permanent magnets 2 are firmly adsorbed to the surface of the box-shaped steel beam, and the center of the hollow part of the heating belt is aligned with the center of the welding groove of the weld, and the two heating belts are respectively connected to the electromagnetic induction heater 4 through the power quick plug connector 3. Among them, the model of the electromagnetic induction heater is MYD-20KW.

[0031] It should be noted that the box-type steel beam is single-sided welded and double-sided formed, so the two heating belts can be arranged on the two symmetrical welding grooves of the box-type steel beam respectively, and there is no need to arrange heating belts on the inner sides opposite to the welding grooves.

[0032] Step 2: insert two thermocouples 5 between the two heating belts and the surface of the box-shaped steel beam respectively, connect the two thermocouples 5 to the electromagnetic induction heater 4 respectively, and set the heating temperature on the electromagnetic induction heater 4.

[0033] Step 3: Start the electromagnetic induction heater 4, and the two heating belts heat the welding groove at the same time. After the temperature displayed on the electromagnetic induction heater 4 reaches the set heating temperature, use an infrared thermometer to measure the surface temperature of the box-shaped steel beam exposed in the hollow part of the heating belt. When the measured temperature differs from the temperature displayed on the electromagnetic induction heater 4 by less than 10°C, start the welding operation;

[0034] Step 4: After welding is completed, set the cooling time on the electromagnetic induction heater 4, and the inner and outer heating belts are cooled slowly at the same time to cool the weld slowly; the cooling time is not shorter than the natural cooling time after the box-shaped steel beam is welded, so as to avoid the influence of too fast natural cooling on the weld.

[0035] Step 5: After the weld has cooled, remove the heating belt and thermocouple 5, and repeat steps 1 to 4 to complete the welding of the other two welding grooves of the box-type steel beam ring weld.

[0036] The heating belt of the present invention does not generate heat itself and has high safety. It does not need to be removed during the welding process and can realize the functions of preheating before welding, heat preservation during welding and slow cooling after welding, effectively preventing the occurrence of high-strength steel welding cracks, thereby ensuring the welding quality.

[0037] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A heating method for welding a ring weld of a box-type steel beam, characterized in that: A flexible temperature-controlled heating belt is used for heating, wherein the flexible temperature-controlled heating belt comprises an induction heating coil, wherein the induction heating coil is a belt-shaped annular hollow structure, and the induction heating coil is packaged by coating a high-temperature resistant fireproof material; a plurality of permanent magnets are evenly distributed on the high-temperature resistant fireproof material, and the permanent magnets are located on the same side, and a power quick-plug connector is connected to the induction heating coil; the specific heating method comprises: Step 1: Arrange the two heating belts symmetrically on the two symmetrical welding grooves of the ring weld of the box-shaped steel beam, straighten and smooth the heating belts, make the permanent magnets firmly adsorbed on the surface of the box-shaped steel beam, and ensure that the center of the hollow part of the heating belt is aligned with the center of the welding groove of the weld, and connect the two heating belts to the electromagnetic induction heater through power quick-plug connectors; the box-shaped steel beam is single-sided welded and double-sided formed; Step 2: insert two thermocouples respectively between the two heating belts and the surface of the box-shaped steel beam, and connect the two thermocouples to the electromagnetic induction heater respectively, and set the heating temperature on the electromagnetic induction heater; Step 3: Start the electromagnetic induction heater, and the two heating belts heat the welding groove at the same time. When the temperature displayed on the electromagnetic induction heater reaches the set heating temperature, use an infrared thermometer to measure the surface temperature of the box-shaped steel beam exposed in the hollow part of the heating belt. When the measured temperature is within 10°C of the temperature displayed on the electromagnetic induction heater, start the welding operation; Step 4: After welding is completed, set the cooling time on the electromagnetic induction heater, and the two heating belts are slowly cooled at the same time to allow the weld to cool slowly; the cooling time is not shorter than the natural cooling time of the box-shaped steel beam after welding; Step 5: Repeat steps 1 to 4 to complete the welding of the other two welding grooves of the box-type steel beam ring weld.

2. The heating method for box-type steel beam girder ring weld welding according to claim 1 is characterized in that: The width of the hollow part is 100-120 mm.

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