Reinforced flash butt welding
1 scope
The technology standard is applicable to industrial and civil construction of hot rolled steel bar continuous flash welding, preheating flash, flash a preheating flash welding.
2 construction preparation
2.1 material and main equipments:
2.1.1 reinforced: reinforced level, diameter must comply with the design requirements, have the factory certificate and retest report. Imported steel shall also have the chemical second-round exam list, its chemical composition should meet the requirements of welding, and shall have the solderability test.
2.1.2 main machines: butt welding machine and supporting platform for the butt welding, protective dark glasses, welding gloves, insulated shoes, steel bar cutting machine, air compressor, water supply, derusting machine or steel wire brush, cold drawn a straight line.
Used for welding machine the main technical data are shown in table 4-20.
Main technical data are commonly used for welding machine table 4-20
Welding machine model UN1-50 UN1-75 UN17 UN2 UN1-100-100-150-1
Moving lever extrusion spring clamp drive CAM gas - hydraulic motor (human manipulation)
Rated capacity of 75 kVA 50, 75, 100, 150
The duty % 25 20 20 20 to 50
Power voltage V 220/380 220/380, 380, 380, 380
Secondary voltage regulating range of 2.9 ~ 7.04 V 2.9 ~ 5.0 4.5 7.6 4.05 8.10 4.05 ~ 7.6
16 16 secondary voltage regulating series 6 August 8
Continuous flash welding steel large diameter 16 mm 10 ~ 12 12 ~ 16 ~ 20 ~ 25 20 ~ 25
Preheating flash welding steel bar diameter 20 ~ 22 32 ~ 36 40 40 40
Largest welding number 50 per hour 75 20 ~ 30, 80, 120
The cooling water consumption L/h 200 200 200 200 600
Compressed air pressure is 0.55 0.6 MPa
Compressed air consumption 15 5 m3 / h
2.2 operation conditions:
2.2.1 welder must hold a valid test certificate.
2.2.2 butt welding machine and supporting device, such as cooling water and compressed air should comply with the requirements.
2.2.3 power should comply with the requirements, when the power supply voltage drop is greater than 5%, less than 8% when, should take appropriate measures to improve welding transformer series. More than 8%, welding should not be conducted.
2.2.4 job site shall have security protection facilities, fire prevention and necessary ventilation measures, prevent burns, electric shock, fire accidents, etc.
2.2.5 familiar with material list, find out joint position, make technical disclosure.
3 operation process
Technological process:
Check equipment to select welding process and parameters, test weld, make simulation specimen and try to send
Determine welding parameter to welding, quality inspection
3.1.1 continuous flash butt welding process:
Closed circuit to flash (two reinforced face touch),
Continuous flash heated to almost melting point (two reinforced face slowly moving contact) - electric upsetting - no electric upsetting
3.1.2 preheating flash butt welding process:
Closed circuit and intermittent flash preheating (two reinforced end alternate contact and separate) - >
Continuous flash heated to almost melting point (two reinforced face slowly moving contact) - electric upsetting - no electric upsetting
3.1.3 flash a preheating flash butt welding process:
Closed circuit and a flash ShanPing end face (two reinforced end face slightly slowly contact) - >
Continuous flash preheating (two reinforced end alternate contact and separate) - >
Quadratic continuous flash heated to almost melting point (two reinforced face slowly moving contact) - electric upsetting - no electric upsetting
3.2 welding method choice: when the steel bar diameter smaller, reinforced level is low, can adopt continuous flash welding. Using continuous flash welding can weld the biggest steel bar diameter should comply with the provisions of the table 4-21. When the steel bar diameter is larger, end face is smooth, appropriate USES preheating flash welding; When the end is not flat, should use the preheating flash flash welding.
Continuous flash welding cap diameter steel table 4-21
Welding machine capacity (kVA) don't grade steel reinforcement bar diameter (mm)
Ⅰ level 25
150 Ⅱ level 22
Ⅲ level 20
Ⅰ level 20
100 Ⅱ 18
Ⅲ level 16
Ⅰ level 16
75 Ⅱ level 14
Ⅲ grade 12
Ⅳ grade steel welding, regardless of the diameter size, all should take preheating flash welding or flash a preheating flash welding process.
3.3 welding parameter choice: flash butt welding, reasonable choose the stretch length, travel allowance, upsetting allowance and welding parameters, such as transformer series. Connection of the flash welding allowance as shown in figure 4-33; Flash - preheating flash welding when the allowance as shown in figure 4-34.
3.4 check the power supply, butt welding machine and butt welding platform, underground laying the insulation of the rubber pad, cooling water, compressed air, etc., all must be in a state of safe and reliable.
Figure 4-33 reinforced continuous flash welding
, - length; + - travel allowance; + - upsetting allowance; + - is there a electric upsetting allowance; + - no electric upsetting allowance
Figure 4-34 reinforced flash - preheating flash welding
, - length; + - a travel allowance; + - second travel allowance; + - preheating allowance;
+ - upsetting allowance; + - is there a electric upsetting allowance; + - no electric upsetting allowance
3.5 test weld, specimen do shift; In each class before welding, should according to the selection of welding parameters, welding 6 specimens, three do tension test, three do cold bending test. After test, can according to determine welding parameters batch production.
3.6 butt welding operation:
3.6.1 track continuous flash welding, after electrify, should borrow rib lever makes the bar end face touch, make its produce heat resistance, and make the reinforcement end protruding part of the melting each other, and the molten metal particles outward injection forming the light flash, then slowly move constantly reinforced forming continuous flash, after being a predetermined flashing allowance disappear, with the appropriate pressure quickly upsetting, which complete the whole continuous flash welding.
3.6.2 preheating flash welding, after electrify, should make the two reinforcement end alternate contact and separate, occurred between the steel bar end face intermittent flash, flashing the preheating process. When preheating process is complete, shall be immediately transferred to continuous flash and upsetting.
3.6.3 flash - preheating flash welding, after electrify, should first to flash, when reinforced end face is smooth, preheating, flash and upsetting process immediately.
3.6.4 radar echoes captured to ensure weld position and operation requirements:
3.6.4.1 before welding and welding process, should check and adjust the electrode position, tighten the clamp screw. Steel bar within the electrode must clamp, electrode jaw deformation should be changing and repair immediately.
3.6.4.2 reinforced end such as bending or into "horseshoe" form shall not be welded, must simmer straight or removed.
3.6.4.3 reinforced end 120 mm within the scope of the rust, oil, must be clear and clean.
3.6.4.4 during the welding process, adhesion on the electrode of iron oxide to clean at any time.
3.6.4.5 close to the proper uniform weld section upsetting deformation, end face should not be oxidized.
3.6.4.6 after welding will loosen electrode cooling on jaw, take out the steel must be smooth, to avoid bending joint.
3.7 quality check: in the steel butt welding production, welding shall be carried out seriously self-checking, if discover the eccentric, bending, burns, cracks and other defects, should be to remove heavy welding joint, and find the reason, eliminate in a timely manner.
4 quality standards
4.1 ensure projects:
4.4.1 the variety and quality of steel must comply with the design requirements and the provisions of the relevant standards.
Note: imported steel should first through chemical composition test and welding test, accord with the relevant provisions of the rear can welding.
Inspection method: inspect the factory certificate and test report.
4.1.2 of the specifications of the steel bar, the position of the welding joint, the percentage of the joint within the same cross section, must comply with the design requirements and norms.
Methods: to observe the or feet quantity check.
4.1.3 butt joint mechanical properties testing must be qualified.
Mechanical properties test, shall be cut at random from each batch of joint 6 specimens, tensile test three, three to do bending test.
Within the same machine-team, by the same welder to complete the 300 level and the diameter of steel welded joint as a batch. If the same affecting welding joint number is less, can be accumulated within one week. If the total is still less than 300 joint, should be calculated on a batch.
Inspection method: inspect welding specimen test report.
4.2 the basic items:
Reinforced flash butt joint appearance inspection results, shall meet the following requirements:
2 joint parts can not have transverse crack.
4.2.2 contact with the electrodes of the steel surface shall not have obvious burns, Ⅳ level when steel welding shall not be burned.
Inspection method: to observe the examination.
4.3 allowable deviation projects:
4.3.1 the bending Angle of joint is not more than 4 °.
4.3.2 the axis of the offset joint, wood is more than 0. L steel bar diameter, at the same time is not more than 2 mm.
Test method: visual or measurement.
5 finished product protection
After welding will loosen electrode cooling on jaw, remove the steel bar must be smooth, to avoid bending joint.
6 should pay attention to quality problems
6.1 in steel butt welding production, should pay attention to any link of the whole welding process, to ensure the welding quality, if the abnormal phenomenon, should refer to table 4-22 to find the reason, eliminate in a timely manner.
Steel butt welding anomalies, welding defects and the prevention measures in table 4-22
Items are abnormal phenomena and defect type check prevention measures
Flashing too severe, and produces strong
The explosion 1. Reduce the transformer series
2. Slow travel speed
2
Flash unstable 1. Remove oxide on the surface of the bottom and electric level
2. Improve the transformer series
3. To speed up the travel together
3
In the joint oxidation film, the lack of penetration or slag
1. Increase the degree of preheating
2. To speed up closer to the upsetting flashing
3. To ensure the electric upsetting process
4. To speed up the upsetting
5. Increase the top forging pressure
4
Shrinkage cavity in joint
1. Reduce the transformer series
2. Avoid flashing process too strong
3. Appropriate increase upsetting allowance and upset forging pressure
5
Weld metal burn or heat affected zone is overheating
1. Reduce the degree of preheating
2. To speed up the burning speed, shorten the welding time
3. Avoid too much electric upsetting
Continue table
Items are abnormal phenomena and defect type check prevention measures
1. Test of reinforced carbon, sulfur and phosphorus content. If do not conform to the regulations, should replace the steel
2. The method of low frequency preheating, increase the degree of preheating
1. Remove the rust of reinforced by clamping part and the oil pollution
2. Remove oxide on the surface of the electrodes
3. Improve the slit shape electrode, increase the contact area
4. The clamping bar
8
Joint bending or axis deviation
1. Adjust the electrode position correctly
2. Trim electrode jaw or replacement has been deformation of the electrode
3. To remove or straightening steel elbow
6.2 cold drawn steel welding shall be carried out before cold drawn. If, during the process of cold drawn in joint fracture occurs, excision of the heat affected zone (about 0.7 times the weld center bar diameter) after welding, again but not more than two times. At the same time, the cold drawing process should conform to requirements for construction and acceptance of concrete structure engineering "(GB50204-92).
7 quality records
This technology standard should have the following quality records:
7.1 steel factory quality certificate or test report.
7.2 second interview report reinforced mechanical properties.
7.3 imported steel chemical composition inspection report and solderability test report. Domestic reinforced brittle fracture occurred during machining process, welding performance and mechanical performance is significantly abnormal, should have a chemical composition inspection report.
7.4 the tensile test of reinforced joint report, bending test report.
1 scope
The technology standard is applicable to industrial and civil construction of hot rolled steel bar continuous flash welding, preheating flash, flash a preheating flash welding.
2 construction preparation
2.1 material and main equipments:
2.1.1 reinforced: reinforced level, diameter must comply with the design requirements, have the factory certificate and retest report. Imported steel shall also have the chemical second-round exam list, its chemical composition should meet the requirements of welding, and shall have the solderability test.
2.1.2 main machines: butt welding machine and supporting platform for the butt welding, protective dark glasses, welding gloves, insulated shoes, steel bar cutting machine, air compressor, water supply, derusting machine or steel wire brush, cold drawn a straight line.
Used for welding machine the main technical data are shown in table 4-20.
Main technical data are commonly used for welding machine table 4-20
Welding machine model UN1-50 UN1-75 UN17 UN2 UN1-100-100-150-1
Moving lever extrusion spring clamp drive CAM gas - hydraulic motor (human manipulation)
Rated capacity of 75 kVA 50, 75, 100, 150
The duty % 25 20 20 20 to 50
Power voltage V 220/380 220/380, 380, 380, 380
Secondary voltage regulating range of 2.9 ~ 7.04 V 2.9 ~ 5.0 4.5 7.6 4.05 8.10 4.05 ~ 7.6
16 16 secondary voltage regulating series 6 August 8
Continuous flash welding steel large diameter 16 mm 10 ~ 12 12 ~ 16 ~ 20 ~ 25 20 ~ 25
Preheating flash welding steel bar diameter 20 ~ 22 32 ~ 36 40 40 40
Largest welding number 50 per hour 75 20 ~ 30, 80, 120
The cooling water consumption L/h 200 200 200 200 600
Compressed air pressure is 0.55 0.6 MPa
Compressed air consumption 15 5 m3 / h
2.2 operation conditions:
2.2.1 welder must hold a valid test certificate.
2.2.2 butt welding machine and supporting device, such as cooling water and compressed air should comply with the requirements.
2.2.3 power should comply with the requirements, when the power supply voltage drop is greater than 5%, less than 8% when, should take appropriate measures to improve welding transformer series. More than 8%, welding should not be conducted.
2.2.4 job site shall have security protection facilities, fire prevention and necessary ventilation measures, prevent burns, electric shock, fire accidents, etc.
2.2.5 familiar with material list, find out joint position, make technical disclosure.
3 operation process
Technological process:
Check equipment to select welding process and parameters, test weld, make simulation specimen and try to send
Determine welding parameter to welding, quality inspection
3.1.1 continuous flash butt welding process:
Closed circuit to flash (two reinforced face touch),
Continuous flash heated to almost melting point (two reinforced face slowly moving contact) - electric upsetting - no electric upsetting
3.1.2 preheating flash butt welding process:
Closed circuit and intermittent flash preheating (two reinforced end alternate contact and separate) - >
Continuous flash heated to almost melting point (two reinforced face slowly moving contact) - electric upsetting - no electric upsetting
3.1.3 flash a preheating flash butt welding process:
Closed circuit and a flash ShanPing end face (two reinforced end face slightly slowly contact) - >
Continuous flash preheating (two reinforced end alternate contact and separate) - >
Quadratic continuous flash heated to almost melting point (two reinforced face slowly moving contact) - electric upsetting - no electric upsetting
3.2 welding method choice: when the steel bar diameter smaller, reinforced level is low, can adopt continuous flash welding. Using continuous flash welding can weld the biggest steel bar diameter should comply with the provisions of the table 4-21. When the steel bar diameter is larger, end face is smooth, appropriate USES preheating flash welding; When the end is not flat, should use the preheating flash flash welding.
Continuous flash welding cap diameter steel table 4-21
Welding machine capacity (kVA) don't grade steel reinforcement bar diameter (mm)
Ⅰ level 25
150 Ⅱ level 22
Ⅲ level 20
Ⅰ level 20
100 Ⅱ 18
Ⅲ level 16
Ⅰ level 16
75 Ⅱ level 14
Ⅲ grade 12
Ⅳ grade steel welding, regardless of the diameter size, all should take preheating flash welding or flash a preheating flash welding process.
3.3 welding parameter choice: flash butt welding, reasonable choose the stretch length, travel allowance, upsetting allowance and welding parameters, such as transformer series. Connection of the flash welding allowance as shown in figure 4-33; Flash - preheating flash welding when the allowance as shown in figure 4-34.
3.4 check the power supply, butt welding machine and butt welding platform, underground laying the insulation of the rubber pad, cooling water, compressed air, etc., all must be in a state of safe and reliable.
Figure 4-33 reinforced continuous flash welding
, - length; + - travel allowance; + - upsetting allowance; + - is there a electric upsetting allowance; + - no electric upsetting allowance
Figure 4-34 reinforced flash - preheating flash welding
, - length; + - a travel allowance; + - second travel allowance; + - preheating allowance;
+ - upsetting allowance; + - is there a electric upsetting allowance; + - no electric upsetting allowance
3.5 test weld, specimen do shift; In each class before welding, should according to the selection of welding parameters, welding 6 specimens, three do tension test, three do cold bending test. After test, can according to determine welding parameters batch production.
3.6 butt welding operation:
3.6.1 track continuous flash welding, after electrify, should borrow rib lever makes the bar end face touch, make its produce heat resistance, and make the reinforcement end protruding part of the melting each other, and the molten metal particles outward injection forming the light flash, then slowly move constantly reinforced forming continuous flash, after being a predetermined flashing allowance disappear, with the appropriate pressure quickly upsetting, which complete the whole continuous flash welding.
3.6.2 preheating flash welding, after electrify, should make the two reinforcement end alternate contact and separate, occurred between the steel bar end face intermittent flash, flashing the preheating process. When preheating process is complete, shall be immediately transferred to continuous flash and upsetting.
3.6.3 flash - preheating flash welding, after electrify, should first to flash, when reinforced end face is smooth, preheating, flash and upsetting process immediately.
3.6.4 radar echoes captured to ensure weld position and operation requirements:
3.6.4.1 before welding and welding process, should check and adjust the electrode position, tighten the clamp screw. Steel bar within the electrode must clamp, electrode jaw deformation should be changing and repair immediately.
3.6.4.2 reinforced end such as bending or into "horseshoe" form shall not be welded, must simmer straight or removed.
3.6.4.3 reinforced end 120 mm within the scope of the rust, oil, must be clear and clean.
3.6.4.4 during the welding process, adhesion on the electrode of iron oxide to clean at any time.
3.6.4.5 close to the proper uniform weld section upsetting deformation, end face should not be oxidized.
3.6.4.6 after welding will loosen electrode cooling on jaw, take out the steel must be smooth, to avoid bending joint.
3.7 quality check: in the steel butt welding production, welding shall be carried out seriously self-checking, if discover the eccentric, bending, burns, cracks and other defects, should be to remove heavy welding joint, and find the reason, eliminate in a timely manner.
4 quality standards
4.1 ensure projects:
4.4.1 the variety and quality of steel must comply with the design requirements and the provisions of the relevant standards.
Note: imported steel should first through chemical composition test and welding test, accord with the relevant provisions of the rear can welding.
Inspection method: inspect the factory certificate and test report.
4.1.2 of the specifications of the steel bar, the position of the welding joint, the percentage of the joint within the same cross section, must comply with the design requirements and norms.
Methods: to observe the or feet quantity check.
4.1.3 butt joint mechanical properties testing must be qualified.
Mechanical properties test, shall be cut at random from each batch of joint 6 specimens, tensile test three, three to do bending test.
Within the same machine-team, by the same welder to complete the 300 level and the diameter of steel welded joint as a batch. If the same affecting welding joint number is less, can be accumulated within one week. If the total is still less than 300 joint, should be calculated on a batch.
Inspection method: inspect welding specimen test report.
4.2 the basic items:
Reinforced flash butt joint appearance inspection results, shall meet the following requirements:
2 joint parts can not have transverse crack.
4.2.2 contact with the electrodes of the steel surface shall not have obvious burns, Ⅳ level when steel welding shall not be burned.
Inspection method: to observe the examination.
4.3 allowable deviation projects:
4.3.1 the bending Angle of joint is not more than 4 °.
4.3.2 the axis of the offset joint, wood is more than 0. L steel bar diameter, at the same time is not more than 2 mm.
Test method: visual or measurement.
5 finished product protection
After welding will loosen electrode cooling on jaw, remove the steel bar must be smooth, to avoid bending joint.
6 should pay attention to quality problems
6.1 in steel butt welding production, should pay attention to any link of the whole welding process, to ensure the welding quality, if the abnormal phenomenon, should refer to table 4-22 to find the reason, eliminate in a timely manner.
Steel butt welding anomalies, welding defects and the prevention measures in table 4-22
Items are abnormal phenomena and defect type check prevention measures
Flashing too severe, and produces strong
The explosion 1. Reduce the transformer series
2. Slow travel speed
2
Flash unstable 1. Remove oxide on the surface of the bottom and electric level
2. Improve the transformer series
3. To speed up the travel together
3
In the joint oxidation film, the lack of penetration or slag
1. Increase the degree of preheating
2. To speed up closer to the upsetting flashing
3. To ensure the electric upsetting process
4. To speed up the upsetting
5. Increase the top forging pressure
4
Shrinkage cavity in joint
1. Reduce the transformer series
2. Avoid flashing process too strong
3. Appropriate increase upsetting allowance and upset forging pressure
5
Weld metal burn or heat affected zone is overheating
1. Reduce the degree of preheating
2. To speed up the burning speed, shorten the welding time
3. Avoid too much electric upsetting
Continue table
Items are abnormal phenomena and defect type check prevention measures
1. Test of reinforced carbon, sulfur and phosphorus content. If do not conform to the regulations, should replace the steel
2. The method of low frequency preheating, increase the degree of preheating
1. Remove the rust of reinforced by clamping part and the oil pollution
2. Remove oxide on the surface of the electrodes
3. Improve the slit shape electrode, increase the contact area
4. The clamping bar
8
Joint bending or axis deviation
1. Adjust the electrode position correctly
2. Trim electrode jaw or replacement has been deformation of the electrode
3. To remove or straightening steel elbow
6.2 cold drawn steel welding shall be carried out before cold drawn. If, during the process of cold drawn in joint fracture occurs, excision of the heat affected zone (about 0.7 times the weld center bar diameter) after welding, again but not more than two times. At the same time, the cold drawing process should conform to requirements for construction and acceptance of concrete structure engineering "(GB50204-92).
7 quality records
This technology standard should have the following quality records:
7.1 steel factory quality certificate or test report.
7.2 second interview report reinforced mechanical properties.
7.3 imported steel chemical composition inspection report and solderability test report. Domestic reinforced brittle fracture occurred during machining process, welding performance and mechanical performance is significantly abnormal, should have a chemical composition inspection report.
7.4 the tensile test of reinforced joint report, bending test report.
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