Narrow gap welding horizontal reinforcing steel bar
1 scope
The technology standard is applicable to industrial and civil building cast-in-place reinforced concrete structure in more than 20 mm in diameter and grade hot-rolled Ⅰ, Ⅱ reinforced field level connection.
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 electrode, electrode of the brand should comply with the regulations of design. If design has no rules, should conform to the requirements of table 4-17, welding quality should meet the following requirements:
Steel welding electrode used brand table 4-17
Don't narrow gap welding a magnitude of steel reinforcement
1
2
Level 3 Ⅰ
Ⅱ level
Grade Ⅲ E5003
E5016
E6016 - D1
Note: do not contain Ⅲ grade steel heat treatment.
2.1.2.1 coated shall be no cracks, porosity, concave and convex inequality defects, and shall not be visible to the naked eye could see eccentricity.
Should 2.1.2.2 during the welding process, arc burning stability, melting and evenly coated nothing block falls off phenomenon.
2.1.2.3 electrode must be according to the requirement of the welding specification to use after drying.
2.1.2.4 electrode must have the factory certificate.
2.1.3 the main machine
2.1.3.1 welding power source, the welding power source can be used the finalize the design product on the market, its size should be able to get 300 a current, no-load voltage 75 v and above.
2.1.3.2 u-shaped copper: U of copper is made up of copper, limit bearing, tightening device consisting of a special mold. U of copper available copper plate suppression or tongbang processing and become, can also be used by a little after electrolytic copper casting processing. Copper size should be adapted to be welded steel bar diameter. A copper is only appropriate to close two diameter steel welding. Copper should have a certain thickness and volume.
2.1.3.3 other machines, welding cable, welding tongs, masks, pads, steel wire brush, saw, has no teeth.
2.2 operation conditions:
2.2.1 welder must hold a valid test certificate.
2.2.2 joint position should comply with the rules.
Then the power should comply with the requirements.
2.2.4 assignments site shall have security protection facilities, and the necessary fire protection and ventilation measures to prevent burns, electric shock, poisoning, fire accident, etc.
2.2.5 familiar with drawings, technical disclosure.
3 operation process
3.1 the process flow
Try to select welding parameters, welding inspection equipment simulation specimen - try to determine welding parameters,
Up to the quality inspection
3.2 check the power supply, welding machine and tools: welding ground should be in contact with the steel bar is good, prevent burns reinforced by striking.
3.3 choosing welding parameters: according to the steel bar diameter, refer to table 4 to 18 choosing welding parameters.
Narrow gap welding horizontal reinforcing steel bar welding parameter table 4 to 18
Steel bar diameter (mm) (mm) electrode gap size (mm) in diameter welding current (A)
20 10 ~ 12 3.2 100 ~ 110
22 10 ~ 12 3.2 100 ~ 110
25 12 ~ 14 4.0 150 ~ 150
28 12 ~ 14 4.0 150 ~ 150
32 12 ~ 14 4.0 150 ~ 150
36 13 ~ 15 5.0 220 ~ 230
40 13 ~ 15 5.0 220 ~ 230
3.4 test weld, do simulation specimen: before the each batch steel welding, should do welding three simulated specimen tensile test, after testing qualified, batch production shall be in accordance with the provisions of the welding parameters.
3.5 applied welding operation main points:
3.5 l steel end should be relatively flat, transverse and vertical axis. Reinforcement application without tooth saws or pneumatic welding cutting machine for cutting. Reinforced by welding parts of rust, oil and water should be clean.
3.5.2 reinforced with a fastening device is fixed and firm, on both sides of copper axis should be consistent, in order to prevent the joint axis offset or bending defects.
3.5.3 reinforced narrow gap welding, the process is as follows: the first step is to face arc ignition electrode inserted into the gap at the bottom side of the steel, and full penetration mouth and molten pool of metal reinforced end more than 1/2 of the gap. Then, arc moved to the other side of the gap at the bottom of the face. Repeat these welds. When necessary, alternate with welding, timely make molten pool of metal, become an organic whole repeatedly to complete welding backing weld. In the second step, electrode gap around before and after the arc, continuous welding, the deposited metal gradually fill gaps 4/5 level. After the third step, the thick to 4/5 of the welding, weld gradually expanding, when necessary, to change
Continuous welding for discontinuous welding, to avoid overheating. The weld residual high shoulds not be more than 3 mm, and should smooth transition to the surface of steel.
3.5.4 down of copper. According to the temperature decide to die. Summer after welding the 3 min detachable mold, open mold after winter period for 5 min. Under 10 ℃ over curved iron plate or rock wool board heat preservation. Premature to deprive weld heat preservation, dismantle joint brittle.
3.6 quality inspection: welding in the welding production joint should be seriously shot for self-checking, if defects are found, should find the reason in a timely manner to eliminate, unqualified and beyond repair joint, should rewelding after removal of the heat affected zone.
4 quality standards
4.1 ensure projects:
4.4.1 quality and varieties of steel, welding rod type, performance, 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 methods. Check the factory certificate and test report.
4.1.2 reinforced specifications, the location of the welded joint, the same section with joint reinforced area percentage, must comply with the design requirements and norms.
Methods: to observe the or feet quantity check.
4.1.3 narrow gap welding head mechanical performance testing must be qualified.
From each batch of joint mechanical properties test, tensile test taken 3 random cut in the joint; According to the requirements of the project, also can take the other three joint bending test.
Welding conditions in the factory, with 300 joint type, with the joint for a batch of steel level.
Under the condition of on-site installation, every one to two floors in 300 with the joint type and level steel joint as a group, with less than 300, is still as a batch.
Inspection method: inspect welding specimen test report.
4.2 basic items: narrow gap welding head should carry on horizontal reinforcing steel bar appearance inspection, the results shall meet the following requirements:
2 weld joint should be full, can not have crack, shall not be greater than 0.5 mm in depth the biting edge.
4.2.2 of the joint axis deviation shall not be more than 0.1 times the bar diameter, at the same time is not more than 2 mm.
Holdings of joint bending is not greater than 4 °.
The weld residual high 4.2.4 joint for 2 ~ 3 mm.
4.2.5 the number and size of weld porosity and slag on all weld surface is less than 2 and 6 was.
Appearance inspection, unqualified joints can be submitted after trimming or reinforcing secondary acceptance. No he can't remedy joint, should rewelding after removal of the heat affected zone.
Test method: visual or measurement.
5 finished product protection
Pay attention to the protection of colligation good has reinforced skeleton, not random on random, non-stick oil, in the construction of the demolition of frame should be carefully repair, ensure reinforcement skeleton each bar in the correct position.
6 should pay attention to quality problems
6.1 as far as possible short arc welding, should be taken to avoid porosity defects.
6.2 the size of the welding current has a direct effect on weld, current weld overheating partial assembly produce brittle organization, current partial moment defects such as porosity, slag inclusion, incomplete fusion. So the welds to choose a suitable current, and maintain a stable current.
6.3 a great influence on the quality of the welding electrode, qualified electrode should be adopted. Welding Ⅱ, Ⅲ reinforcement, using the electrode of low hydrogen type basic electrode, before welding, welding rod to baking, according to the requirement of the specification and in the insulation cylinder for standby. After insulation tube into the construction site to the welding machine, keep the barrel temperature is 150 ℃. Electrode root take 1 root was applied, the cooling of the electrode can bake again, but not for the third time.
6.4 rain, snow and fog days is not allowed to open welding.
6.5 under the condition of environment temperature below 5 ℃ during welding, for steel welding at low temperature, low temperature welding, welding current should be slightly increased.
7 quality records
This technology standard should have the following quality records:
7.1 steel factory quality certificate or test report.
7.2 steel mechanical performance test report.
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 steel joint tensile test report.
7.5 electrode factory certificate.
1 scope
The technology standard is applicable to industrial and civil building cast-in-place reinforced concrete structure in more than 20 mm in diameter and grade hot-rolled Ⅰ, Ⅱ reinforced field level connection.
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 electrode, electrode of the brand should comply with the regulations of design. If design has no rules, should conform to the requirements of table 4-17, welding quality should meet the following requirements:
Steel welding electrode used brand table 4-17
Don't narrow gap welding a magnitude of steel reinforcement
1
2
Level 3 Ⅰ
Ⅱ level
Grade Ⅲ E5003
E5016
E6016 - D1
Note: do not contain Ⅲ grade steel heat treatment.
2.1.2.1 coated shall be no cracks, porosity, concave and convex inequality defects, and shall not be visible to the naked eye could see eccentricity.
Should 2.1.2.2 during the welding process, arc burning stability, melting and evenly coated nothing block falls off phenomenon.
2.1.2.3 electrode must be according to the requirement of the welding specification to use after drying.
2.1.2.4 electrode must have the factory certificate.
2.1.3 the main machine
2.1.3.1 welding power source, the welding power source can be used the finalize the design product on the market, its size should be able to get 300 a current, no-load voltage 75 v and above.
2.1.3.2 u-shaped copper: U of copper is made up of copper, limit bearing, tightening device consisting of a special mold. U of copper available copper plate suppression or tongbang processing and become, can also be used by a little after electrolytic copper casting processing. Copper size should be adapted to be welded steel bar diameter. A copper is only appropriate to close two diameter steel welding. Copper should have a certain thickness and volume.
2.1.3.3 other machines, welding cable, welding tongs, masks, pads, steel wire brush, saw, has no teeth.
2.2 operation conditions:
2.2.1 welder must hold a valid test certificate.
2.2.2 joint position should comply with the rules.
Then the power should comply with the requirements.
2.2.4 assignments site shall have security protection facilities, and the necessary fire protection and ventilation measures to prevent burns, electric shock, poisoning, fire accident, etc.
2.2.5 familiar with drawings, technical disclosure.
3 operation process
3.1 the process flow
Try to select welding parameters, welding inspection equipment simulation specimen - try to determine welding parameters,
Up to the quality inspection
3.2 check the power supply, welding machine and tools: welding ground should be in contact with the steel bar is good, prevent burns reinforced by striking.
3.3 choosing welding parameters: according to the steel bar diameter, refer to table 4 to 18 choosing welding parameters.
Narrow gap welding horizontal reinforcing steel bar welding parameter table 4 to 18
Steel bar diameter (mm) (mm) electrode gap size (mm) in diameter welding current (A)
20 10 ~ 12 3.2 100 ~ 110
22 10 ~ 12 3.2 100 ~ 110
25 12 ~ 14 4.0 150 ~ 150
28 12 ~ 14 4.0 150 ~ 150
32 12 ~ 14 4.0 150 ~ 150
36 13 ~ 15 5.0 220 ~ 230
40 13 ~ 15 5.0 220 ~ 230
3.4 test weld, do simulation specimen: before the each batch steel welding, should do welding three simulated specimen tensile test, after testing qualified, batch production shall be in accordance with the provisions of the welding parameters.
3.5 applied welding operation main points:
3.5 l steel end should be relatively flat, transverse and vertical axis. Reinforcement application without tooth saws or pneumatic welding cutting machine for cutting. Reinforced by welding parts of rust, oil and water should be clean.
3.5.2 reinforced with a fastening device is fixed and firm, on both sides of copper axis should be consistent, in order to prevent the joint axis offset or bending defects.
3.5.3 reinforced narrow gap welding, the process is as follows: the first step is to face arc ignition electrode inserted into the gap at the bottom side of the steel, and full penetration mouth and molten pool of metal reinforced end more than 1/2 of the gap. Then, arc moved to the other side of the gap at the bottom of the face. Repeat these welds. When necessary, alternate with welding, timely make molten pool of metal, become an organic whole repeatedly to complete welding backing weld. In the second step, electrode gap around before and after the arc, continuous welding, the deposited metal gradually fill gaps 4/5 level. After the third step, the thick to 4/5 of the welding, weld gradually expanding, when necessary, to change
Continuous welding for discontinuous welding, to avoid overheating. The weld residual high shoulds not be more than 3 mm, and should smooth transition to the surface of steel.
3.5.4 down of copper. According to the temperature decide to die. Summer after welding the 3 min detachable mold, open mold after winter period for 5 min. Under 10 ℃ over curved iron plate or rock wool board heat preservation. Premature to deprive weld heat preservation, dismantle joint brittle.
3.6 quality inspection: welding in the welding production joint should be seriously shot for self-checking, if defects are found, should find the reason in a timely manner to eliminate, unqualified and beyond repair joint, should rewelding after removal of the heat affected zone.
4 quality standards
4.1 ensure projects:
4.4.1 quality and varieties of steel, welding rod type, performance, 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 methods. Check the factory certificate and test report.
4.1.2 reinforced specifications, the location of the welded joint, the same section with joint reinforced area percentage, must comply with the design requirements and norms.
Methods: to observe the or feet quantity check.
4.1.3 narrow gap welding head mechanical performance testing must be qualified.
From each batch of joint mechanical properties test, tensile test taken 3 random cut in the joint; According to the requirements of the project, also can take the other three joint bending test.
Welding conditions in the factory, with 300 joint type, with the joint for a batch of steel level.
Under the condition of on-site installation, every one to two floors in 300 with the joint type and level steel joint as a group, with less than 300, is still as a batch.
Inspection method: inspect welding specimen test report.
4.2 basic items: narrow gap welding head should carry on horizontal reinforcing steel bar appearance inspection, the results shall meet the following requirements:
2 weld joint should be full, can not have crack, shall not be greater than 0.5 mm in depth the biting edge.
4.2.2 of the joint axis deviation shall not be more than 0.1 times the bar diameter, at the same time is not more than 2 mm.
Holdings of joint bending is not greater than 4 °.
The weld residual high 4.2.4 joint for 2 ~ 3 mm.
4.2.5 the number and size of weld porosity and slag on all weld surface is less than 2 and 6 was.
Appearance inspection, unqualified joints can be submitted after trimming or reinforcing secondary acceptance. No he can't remedy joint, should rewelding after removal of the heat affected zone.
Test method: visual or measurement.
5 finished product protection
Pay attention to the protection of colligation good has reinforced skeleton, not random on random, non-stick oil, in the construction of the demolition of frame should be carefully repair, ensure reinforcement skeleton each bar in the correct position.
6 should pay attention to quality problems
6.1 as far as possible short arc welding, should be taken to avoid porosity defects.
6.2 the size of the welding current has a direct effect on weld, current weld overheating partial assembly produce brittle organization, current partial moment defects such as porosity, slag inclusion, incomplete fusion. So the welds to choose a suitable current, and maintain a stable current.
6.3 a great influence on the quality of the welding electrode, qualified electrode should be adopted. Welding Ⅱ, Ⅲ reinforcement, using the electrode of low hydrogen type basic electrode, before welding, welding rod to baking, according to the requirement of the specification and in the insulation cylinder for standby. After insulation tube into the construction site to the welding machine, keep the barrel temperature is 150 ℃. Electrode root take 1 root was applied, the cooling of the electrode can bake again, but not for the third time.
6.4 rain, snow and fog days is not allowed to open welding.
6.5 under the condition of environment temperature below 5 ℃ during welding, for steel welding at low temperature, low temperature welding, welding current should be slightly increased.
7 quality records
This technology standard should have the following quality records:
7.1 steel factory quality certificate or test report.
7.2 steel mechanical performance test report.
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 steel joint tensile test report.
7.5 electrode factory certificate.
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