Steel manual arc welding
1 scope
The technology standard is applicable to industrial and civil construction steel and built-in parts manual electric arc 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. Embedded parts of Ⅰ, Ⅱ grade steel anchor application. Reinforcement should be no rust and oil pollution.
2.1.2 steel: steel embedded parts shall not have deformation, crack, rust, spot, the section size and mechanical properties shall comply with the design requirements.
2.1.3 electrode, electrode of the brand should comply with the regulations of design. If design has no rules, should conform to the requirements of table 4-14, welding quality should meet the following requirements:
Steel welding electrode used brand table 4 to 14
Items are reinforced level lap welding, help the welding groove welding
Level 1 Ⅰ E4303 E4303 E4303
Level 2 Ⅱ E4303 E4303 E5003
Level 3 Ⅲ E5003 E5003 E5503
4 Ⅰ, Ⅱ E4303 with steel plate welding
Note: do not contain 25 mnsi steel bar.
2.1.3.1 coated shall be no cracks, porosity, concave and convex inequality defects, and shall not be visible to the naked eye could see eccentricity.
Should 2.1.3.2 during the welding process, arc burning stability, melting and evenly coated nothing block falls off phenomenon.
2.1.3.3 electrode must be according to the requirement of the welding specification to use after drying.
2.1.3.4 electrode must have the factory certificate.
2.1.4 arc welding machine, welding cable, welding tongs, masks, cut, wire brush, file, hammer, steel figure, etc.
2.2 operation conditions:
2.2.1 welder must hold a certification exam.
Article 2.2.2 for size, groove Angle, steel end clearance, joint position and steel axis should comply with the rules.
Then the power should comply with the requirements.
2.2.4 job site to have the necessary safety protection facilities, fire prevention and ventilation measures to prevent burns, electric shock, poisoning, fire accident, etc.
2.2.5 familiar with drawings, technical exchanges.
3 operation process
3.1 process:
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 choose welding parameters. According to the level of reinforcement, diameter, joint type and welding position, choose suitable electrode diameter, welding layer number and welding current, ensure good weld fusion and rc.
3.4 test weld, do simulation specimens. Before the formal each batch steel welding, welding should be three simulation do tension test specimen, after test, can according to determine welding parameters of batch production.
3.5 welds operation:
3.5.1 track of arc: plate or the help of the joint, arc is performed on the steel plate or help. No steel plate or without the help of the joint, arc should be part of the formation of weld, the main reinforcement to prevent burns.
3.5.2 positioning: when welding welding welding anchor point again first.
3.5.3 stretch: stretch the straight line, horizontal swing and sent to the electrode three actions to coordinate smoothly.
3.5.4 are-receive: when you receive arc, molten pool should be fill in, pull out the arc, the molten pool should be fill in, be careful not to cause arc scratch in work surfaces.
2.6.2 multi-layer welding, such as reinforcing bar diameter is larger, multi-layer welds are required should be layered continuous welding, each layer after welding, slag removal and welding the next layer. Should guarantee the weld height and length.
3.5.6 fusion: during the welding process should be sufficient penetration. Main weld and position of weld should be combined with good, avoid porosity, slag inclusion and burn defects, and prevent the cracks.
3.5.7 flat, flat welding should pay attention to the phenomenon of slag and molten iron, prevent slag flow to the front of the molten iron. Molten pool also should control into oval, generally using the right welding method, welding rod and working surface to 70 °.
3.5.8 vertical: vertical welding, hot metal and slag is easily separated. To prevent molten pool temperature is too high, hot metal drop flash formation, operation electrode and vertical plane form 60 ° ~ 80 ° Angle. Make the arc slightly upward, blowing bath center. Arc welding first, pin up article, at the same time as a smaller transverse swing, the rest of the each layer with a semicircular horizontal swing and pick up the welding arc method.
3.5.9 horizontal; Electrode rotated 70 ° ~ 70 °, prevent molten iron sank to the factory by the weight of groove. Stretch to the uphill mouth does not make the arc pause, quickly to downhill mouth roots as a tiny transverse stability of arc movement, average for welding in turn.
3.5.10 overhead welding: overhead welding time short arc welding with small current, dissolved in appropriate thin, shall ensure that with the parent metal in good fusion. Before and after the first layer of weld with short arc push pull, welding rod and welding direction into 8 ° ~ 90 ° Angle. The rest of the every layer electrode horizontal pendulum, and in the groove side slightly pause arc stability, guarantee on both sides of the fusion.
Article 3.5.11 reinforcement for welding.
Article 3.5.11.1 reinforcement for welding is suitable for the Ⅰ, Ⅱ, Ⅲ grade steel. Reinforcement for the appropriate USES double welding, welding as shown in figure 4-27 (a), cannot undertake welding by both sides, also can use welding by one side, as shown in figure 4-27 (b).
Figure 4-27 steel welding head
Article for appropriate USES level with the main muscle, with the diameter of the reinforcing bar, the article for the length l are shown in table 4 to 15. Article such as help the level with the main reinforcement phase at the same time, the diameter of the article for a specification can be smaller than the main bar diameter. Such as help bar diameter and the main reinforcement phase at the same time, help of reinforced low than the main reinforcement in a level.
3.5.11.2 reinforced for a joint weld thickness should be not less than 0.3 d h, weld width is not less than 0.7 d, b as shown in figure 4 to 28.
Reinforced help article length table 4 to 15
A second level of steel weld type help article length l
The single side welding
Double sided welding or 8 d
4 d or higher
The single side welding
Double sided welding 10 or more d
5 d or higher
Note: d's diameter.
Figure 4-28 weld size diagram
A - weld width; Figure 4-29 h - the thickness of the weld
3.5.11.3 reinforcement for welding, steel assembly and welding shall meet the following requirements:
A. between two main reinforcement end, should be 2 ~ 5 mm gap.
B. article to help with the main muscle between with four fixed location, location of weld should help end of article 20 mm above.
C. welding, arc should be at one end of the article to help start, arc shall be on the end of the article for the reinforcement, arc pit should be filled. The first layer of weld should have enough penetration, Lord and position of weld seam, especially in the beginning of the weld and terminal, should be good fusion.
3.5.12 reinforced lap welding:
3.5.12.1 reinforced lap welding: suitable for Ⅰ, Ⅱ, Ⅲ grade steel. When welding, appropriate USES welding by both sides, as shown in figure 4-29 (a). Wood can do double-sided welding, also can be used welding by one side, as shown in figure 4-29 (b). The lap length l should be with the help of the same length, are shown in table 4 to 15.
3.5.12.2 lap joint weld thickness h should be not less than 0.3 d, weld width b no less than 0.7 d.
3.5.12.3 lap welding, the assembly and welding steel shall meet the following requirements:
A. lap welding, steel bar should be bending, in order to make sure the axis of the two steel on an axis.
Under the condition of prefabricated field installation, the overlap between node steel welding, such as steel bar bending and difficulties, can be appropriately bending.
B. lap welding, with two fixed, localization of weld joints should be from the end more than 20 mm.
C. welding, arc should be at one end of the lap steel bar, the arc should be on the end of the lap steel, arc pit should be filled. The first layer of weld should have enough penetration, Lord and position of weld seam, especially in the beginning of the weld and terminal, should be good fusion.
3.5.13 embedded parts tee joint arc welding: embedded parts tee joint arc welding joint form of fillet weld and perforated plug welding, as shown in figure 4-30.
Figure 4-30 embedded parts tee joint
(a) fillet welding; (b) perforated plug
When welding, shall meet the following requirements:
Delta 3.5.13.1 steel plate thickness is not less than 0.6 d, and should not be less than 6 mm.
3.5.13.2 reinforced Ⅰ, Ⅱ level should be adopted. Stress anchor reinforcement should not be less than 8 mm diameter, structure anchor reinforcement should not be less than 6 mm diameter. The anchoring reinforcement within 6 ~ 25 mm in diameter, can use fillet welding; Anchor bar diameter of 20 ~ 32 mm, appropriate USES perforated plug welding.
3.5.13.3 using Ⅰ grade steel, fillet weld leg K is not less than 0.5 d; Using Ⅱ grade steel, welding seam welding feet k is not less than 0.6 d.
3.5.13.4 welding current shoulds not be too large, it is forbidden to burn reinforced.
3.5.14 reinforced with steel plate lap welding: reinforced with steel plate lap welding, the joint form shown in figure 4-31. Ⅰ level reinforced the lap length l of not less than 5 d. Weld width b not less than 0.5 d, weld thickness h is not less than 0.35 d.
Figure 4-31 reinforced with steel plate lap joint
3.5.15 in the installation of prefabricated frame structure, the steel welding shall meet the following requirements.
3.5.15.1 two steel axis offset is larger, appropriate USES cold bending straightening, but shall not use the hammers. Such as cold bending straightening have difficulty, can use oxyacetylene flame correction after heating, the heating temperature shall not exceed 850 ℃, reinforcement to avoid burns.
3.5.15.2 during welding, should choose the reasonable welding sequence, the column between nodes, can be symmetrical welding, to reduce the deformation of the structure.
3.5.16 reinforced low temperature welding:
3.5.6.1 at ambient temperature below 5 ℃ under the condition of welding, for steel welding at low temperature. The welding of low temperature, in addition to comply with the relevant provisions of the normal temperature welding, should adjust the welding process parameters, the welding seam and heat affected zone slow cooling. Wind more than 4, the measures should file the wind. Not cooling after welding joint should avoid touching the ice and snow.
3.5.16.2 reinforced the arc welding of low temperature and welding process shall meet the following requirements:
A. to help flat welding or lap welding, the first layer of weld, arc in the middle, and the first to carry arc on both ends; When vertical, from middle to top first arc, arc, again from the bottom to the middle in order to make the reinforced connector end as part of the preheating effect. Each layer seam welding in the future, adopt hierarchical welding temperature control. Interpass temperature control between 150 ~ 350 ℃, to have the effect of slow cooling.
B. Ⅱ, Ⅲ steel welding joint for multi-layer welds, using "back HuoHan welding method", is finally back to HuoHan length than the top layer of weld in shortened 4 ~ 6 mm is at each end, as shown in figure 4-32, to eliminate or reduce weld layer and the hardening of the overheating of organization, to improve the performance of the joint.
Figure 4-32 reinforced low temperature welding back HuoHan schematic diagram
(a) for welding; (b) lap welding; (c) groove welding
C. slightly increase welding current, welding speed slow down appropriately.
4 quality standards
4.1 ensure projects:
4.4.1 quality and varieties of steel, welding rod used in the brand, performance, and the joint of steel plate and steel, both 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 reinforced specifications, the location of the welded joint, the percentage of the joint in the same cross-section must comply with the design requirements and construction norms.
Methods: to observe the or feet quantity check.
4.1.3 the strength of the welding joint inspection must be qualified.
From the finished product taking five connectors for each batch of the tensile test. For steel welding joint of fabricated structure node, according to production conditions to make simulation specimens.
Welding conditions in the factory, with 300 type connector (with reinforced level, with the joint type) as a group.
Under the condition of on-site installation, every one to two floors with 300 types of connectors (and the level of reinforcement, and the joint type, and welding position) as a group, less than 300, is still as a batch.
Inspection method: inspect welding specimen test report.
4.2 basic items: the operator should be in joint slag removal after inspect the appearance quality of the weldment, the inspection result shall meet the following requirements:
2 welding surface level off, can not have larger sag, flash.
4.2.2 must not have joint crack.
Holdings bit depth, the number and size of porosity, slag inclusion, as well as the joint size deviation, shall not exceed the value given in table 4 to 16.
Rebar arc joint size deviation and defect permitted (mm) table 4-16
Will project allow deviation test methods
Article 1 for the amount of vertical migration d 0.5 feet along the center line of the joint
Joint bending
Embedded parts 4 ° T joint space between steel
Not more than 10
3 reinforced joint axis offset of 0.1 d and quantity is not more than 3 feet
+ 0.05 d
0
0.1 d
0
Amount of feet
Weld length of 6-0.5 d
7 cross bite edge 0.5 visual depth
The number and size of weld porosity and slag in 2 d long welding
Embedded inserts tee joint seam surface porosity of 2, 6 mm23,
The diameter is not more than 1.5
Note: 1. D for the steel bar diameter.
2. Under negative temperature, bite edge depth is not greater than 0.2 mm.
Appearance inspection, unqualified joints can be submitted after trimming or reinforcing secondary acceptance.
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 to repair, ensure reinforced skeleton reinforced location is correct.
6 should pay attention to quality problems
Article 6.1 check for size, end clearance groove Angle, steel, steel axis deviation, and surface quality of steel, is not in conformity with the requirements shall not be welded.
6.2 take the wiring should be in contact with the steel is good, do not get optional disorderly, prevent the arc.
Article 6.3 with steel plate or help joint, arc is performed on the steel plate or help. No steel plate or without the help of the joint, arc should be in the form of weld spot, shall not be arbitrarily arc, the main reinforcement to prevent burns.
6.4 according to the level of reinforcement, diameter, joint type and welding position, choose suitable electrode diameter and welding current, ensure good weld fusion and rc.
6.5 timely slag removal in the process of welding, the weld surface smooth level off, the weld appearance, strengthen the weld should be smooth transition, arc pit should be filled.
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 having reinforced tee joint tensile test report.
7.6 electrode factory certificate.
1 scope
The technology standard is applicable to industrial and civil construction steel and built-in parts manual electric arc 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. Embedded parts of Ⅰ, Ⅱ grade steel anchor application. Reinforcement should be no rust and oil pollution.
2.1.2 steel: steel embedded parts shall not have deformation, crack, rust, spot, the section size and mechanical properties shall comply with the design requirements.
2.1.3 electrode, electrode of the brand should comply with the regulations of design. If design has no rules, should conform to the requirements of table 4-14, welding quality should meet the following requirements:
Steel welding electrode used brand table 4 to 14
Items are reinforced level lap welding, help the welding groove welding
Level 1 Ⅰ E4303 E4303 E4303
Level 2 Ⅱ E4303 E4303 E5003
Level 3 Ⅲ E5003 E5003 E5503
4 Ⅰ, Ⅱ E4303 with steel plate welding
Note: do not contain 25 mnsi steel bar.
2.1.3.1 coated shall be no cracks, porosity, concave and convex inequality defects, and shall not be visible to the naked eye could see eccentricity.
Should 2.1.3.2 during the welding process, arc burning stability, melting and evenly coated nothing block falls off phenomenon.
2.1.3.3 electrode must be according to the requirement of the welding specification to use after drying.
2.1.3.4 electrode must have the factory certificate.
2.1.4 arc welding machine, welding cable, welding tongs, masks, cut, wire brush, file, hammer, steel figure, etc.
2.2 operation conditions:
2.2.1 welder must hold a certification exam.
Article 2.2.2 for size, groove Angle, steel end clearance, joint position and steel axis should comply with the rules.
Then the power should comply with the requirements.
2.2.4 job site to have the necessary safety protection facilities, fire prevention and ventilation measures to prevent burns, electric shock, poisoning, fire accident, etc.
2.2.5 familiar with drawings, technical exchanges.
3 operation process
3.1 process:
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 choose welding parameters. According to the level of reinforcement, diameter, joint type and welding position, choose suitable electrode diameter, welding layer number and welding current, ensure good weld fusion and rc.
3.4 test weld, do simulation specimens. Before the formal each batch steel welding, welding should be three simulation do tension test specimen, after test, can according to determine welding parameters of batch production.
3.5 welds operation:
3.5.1 track of arc: plate or the help of the joint, arc is performed on the steel plate or help. No steel plate or without the help of the joint, arc should be part of the formation of weld, the main reinforcement to prevent burns.
3.5.2 positioning: when welding welding welding anchor point again first.
3.5.3 stretch: stretch the straight line, horizontal swing and sent to the electrode three actions to coordinate smoothly.
3.5.4 are-receive: when you receive arc, molten pool should be fill in, pull out the arc, the molten pool should be fill in, be careful not to cause arc scratch in work surfaces.
2.6.2 multi-layer welding, such as reinforcing bar diameter is larger, multi-layer welds are required should be layered continuous welding, each layer after welding, slag removal and welding the next layer. Should guarantee the weld height and length.
3.5.6 fusion: during the welding process should be sufficient penetration. Main weld and position of weld should be combined with good, avoid porosity, slag inclusion and burn defects, and prevent the cracks.
3.5.7 flat, flat welding should pay attention to the phenomenon of slag and molten iron, prevent slag flow to the front of the molten iron. Molten pool also should control into oval, generally using the right welding method, welding rod and working surface to 70 °.
3.5.8 vertical: vertical welding, hot metal and slag is easily separated. To prevent molten pool temperature is too high, hot metal drop flash formation, operation electrode and vertical plane form 60 ° ~ 80 ° Angle. Make the arc slightly upward, blowing bath center. Arc welding first, pin up article, at the same time as a smaller transverse swing, the rest of the each layer with a semicircular horizontal swing and pick up the welding arc method.
3.5.9 horizontal; Electrode rotated 70 ° ~ 70 °, prevent molten iron sank to the factory by the weight of groove. Stretch to the uphill mouth does not make the arc pause, quickly to downhill mouth roots as a tiny transverse stability of arc movement, average for welding in turn.
3.5.10 overhead welding: overhead welding time short arc welding with small current, dissolved in appropriate thin, shall ensure that with the parent metal in good fusion. Before and after the first layer of weld with short arc push pull, welding rod and welding direction into 8 ° ~ 90 ° Angle. The rest of the every layer electrode horizontal pendulum, and in the groove side slightly pause arc stability, guarantee on both sides of the fusion.
Article 3.5.11 reinforcement for welding.
Article 3.5.11.1 reinforcement for welding is suitable for the Ⅰ, Ⅱ, Ⅲ grade steel. Reinforcement for the appropriate USES double welding, welding as shown in figure 4-27 (a), cannot undertake welding by both sides, also can use welding by one side, as shown in figure 4-27 (b).
Figure 4-27 steel welding head
Article for appropriate USES level with the main muscle, with the diameter of the reinforcing bar, the article for the length l are shown in table 4 to 15. Article such as help the level with the main reinforcement phase at the same time, the diameter of the article for a specification can be smaller than the main bar diameter. Such as help bar diameter and the main reinforcement phase at the same time, help of reinforced low than the main reinforcement in a level.
3.5.11.2 reinforced for a joint weld thickness should be not less than 0.3 d h, weld width is not less than 0.7 d, b as shown in figure 4 to 28.
Reinforced help article length table 4 to 15
A second level of steel weld type help article length l
The single side welding
Double sided welding or 8 d
4 d or higher
The single side welding
Double sided welding 10 or more d
5 d or higher
Note: d's diameter.
Figure 4-28 weld size diagram
A - weld width; Figure 4-29 h - the thickness of the weld
3.5.11.3 reinforcement for welding, steel assembly and welding shall meet the following requirements:
A. between two main reinforcement end, should be 2 ~ 5 mm gap.
B. article to help with the main muscle between with four fixed location, location of weld should help end of article 20 mm above.
C. welding, arc should be at one end of the article to help start, arc shall be on the end of the article for the reinforcement, arc pit should be filled. The first layer of weld should have enough penetration, Lord and position of weld seam, especially in the beginning of the weld and terminal, should be good fusion.
3.5.12 reinforced lap welding:
3.5.12.1 reinforced lap welding: suitable for Ⅰ, Ⅱ, Ⅲ grade steel. When welding, appropriate USES welding by both sides, as shown in figure 4-29 (a). Wood can do double-sided welding, also can be used welding by one side, as shown in figure 4-29 (b). The lap length l should be with the help of the same length, are shown in table 4 to 15.
3.5.12.2 lap joint weld thickness h should be not less than 0.3 d, weld width b no less than 0.7 d.
3.5.12.3 lap welding, the assembly and welding steel shall meet the following requirements:
A. lap welding, steel bar should be bending, in order to make sure the axis of the two steel on an axis.
Under the condition of prefabricated field installation, the overlap between node steel welding, such as steel bar bending and difficulties, can be appropriately bending.
B. lap welding, with two fixed, localization of weld joints should be from the end more than 20 mm.
C. welding, arc should be at one end of the lap steel bar, the arc should be on the end of the lap steel, arc pit should be filled. The first layer of weld should have enough penetration, Lord and position of weld seam, especially in the beginning of the weld and terminal, should be good fusion.
3.5.13 embedded parts tee joint arc welding: embedded parts tee joint arc welding joint form of fillet weld and perforated plug welding, as shown in figure 4-30.
Figure 4-30 embedded parts tee joint
(a) fillet welding; (b) perforated plug
When welding, shall meet the following requirements:
Delta 3.5.13.1 steel plate thickness is not less than 0.6 d, and should not be less than 6 mm.
3.5.13.2 reinforced Ⅰ, Ⅱ level should be adopted. Stress anchor reinforcement should not be less than 8 mm diameter, structure anchor reinforcement should not be less than 6 mm diameter. The anchoring reinforcement within 6 ~ 25 mm in diameter, can use fillet welding; Anchor bar diameter of 20 ~ 32 mm, appropriate USES perforated plug welding.
3.5.13.3 using Ⅰ grade steel, fillet weld leg K is not less than 0.5 d; Using Ⅱ grade steel, welding seam welding feet k is not less than 0.6 d.
3.5.13.4 welding current shoulds not be too large, it is forbidden to burn reinforced.
3.5.14 reinforced with steel plate lap welding: reinforced with steel plate lap welding, the joint form shown in figure 4-31. Ⅰ level reinforced the lap length l of not less than 5 d. Weld width b not less than 0.5 d, weld thickness h is not less than 0.35 d.
Figure 4-31 reinforced with steel plate lap joint
3.5.15 in the installation of prefabricated frame structure, the steel welding shall meet the following requirements.
3.5.15.1 two steel axis offset is larger, appropriate USES cold bending straightening, but shall not use the hammers. Such as cold bending straightening have difficulty, can use oxyacetylene flame correction after heating, the heating temperature shall not exceed 850 ℃, reinforcement to avoid burns.
3.5.15.2 during welding, should choose the reasonable welding sequence, the column between nodes, can be symmetrical welding, to reduce the deformation of the structure.
3.5.16 reinforced low temperature welding:
3.5.6.1 at ambient temperature below 5 ℃ under the condition of welding, for steel welding at low temperature. The welding of low temperature, in addition to comply with the relevant provisions of the normal temperature welding, should adjust the welding process parameters, the welding seam and heat affected zone slow cooling. Wind more than 4, the measures should file the wind. Not cooling after welding joint should avoid touching the ice and snow.
3.5.16.2 reinforced the arc welding of low temperature and welding process shall meet the following requirements:
A. to help flat welding or lap welding, the first layer of weld, arc in the middle, and the first to carry arc on both ends; When vertical, from middle to top first arc, arc, again from the bottom to the middle in order to make the reinforced connector end as part of the preheating effect. Each layer seam welding in the future, adopt hierarchical welding temperature control. Interpass temperature control between 150 ~ 350 ℃, to have the effect of slow cooling.
B. Ⅱ, Ⅲ steel welding joint for multi-layer welds, using "back HuoHan welding method", is finally back to HuoHan length than the top layer of weld in shortened 4 ~ 6 mm is at each end, as shown in figure 4-32, to eliminate or reduce weld layer and the hardening of the overheating of organization, to improve the performance of the joint.
Figure 4-32 reinforced low temperature welding back HuoHan schematic diagram
(a) for welding; (b) lap welding; (c) groove welding
C. slightly increase welding current, welding speed slow down appropriately.
4 quality standards
4.1 ensure projects:
4.4.1 quality and varieties of steel, welding rod used in the brand, performance, and the joint of steel plate and steel, both 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 reinforced specifications, the location of the welded joint, the percentage of the joint in the same cross-section must comply with the design requirements and construction norms.
Methods: to observe the or feet quantity check.
4.1.3 the strength of the welding joint inspection must be qualified.
From the finished product taking five connectors for each batch of the tensile test. For steel welding joint of fabricated structure node, according to production conditions to make simulation specimens.
Welding conditions in the factory, with 300 type connector (with reinforced level, with the joint type) as a group.
Under the condition of on-site installation, every one to two floors with 300 types of connectors (and the level of reinforcement, and the joint type, and welding position) as a group, less than 300, is still as a batch.
Inspection method: inspect welding specimen test report.
4.2 basic items: the operator should be in joint slag removal after inspect the appearance quality of the weldment, the inspection result shall meet the following requirements:
2 welding surface level off, can not have larger sag, flash.
4.2.2 must not have joint crack.
Holdings bit depth, the number and size of porosity, slag inclusion, as well as the joint size deviation, shall not exceed the value given in table 4 to 16.
Rebar arc joint size deviation and defect permitted (mm) table 4-16
Will project allow deviation test methods
Article 1 for the amount of vertical migration d 0.5 feet along the center line of the joint
Joint bending
Embedded parts 4 ° T joint space between steel
Not more than 10
3 reinforced joint axis offset of 0.1 d and quantity is not more than 3 feet
+ 0.05 d
0
0.1 d
0
Amount of feet
Weld length of 6-0.5 d
7 cross bite edge 0.5 visual depth
The number and size of weld porosity and slag in 2 d long welding
Embedded inserts tee joint seam surface porosity of 2, 6 mm23,
The diameter is not more than 1.5
Note: 1. D for the steel bar diameter.
2. Under negative temperature, bite edge depth is not greater than 0.2 mm.
Appearance inspection, unqualified joints can be submitted after trimming or reinforcing secondary acceptance.
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 to repair, ensure reinforced skeleton reinforced location is correct.
6 should pay attention to quality problems
Article 6.1 check for size, end clearance groove Angle, steel, steel axis deviation, and surface quality of steel, is not in conformity with the requirements shall not be welded.
6.2 take the wiring should be in contact with the steel is good, do not get optional disorderly, prevent the arc.
Article 6.3 with steel plate or help joint, arc is performed on the steel plate or help. No steel plate or without the help of the joint, arc should be in the form of weld spot, shall not be arbitrarily arc, the main reinforcement to prevent burns.
6.4 according to the level of reinforcement, diameter, joint type and welding position, choose suitable electrode diameter and welding current, ensure good weld fusion and rc.
6.5 timely slag removal in the process of welding, the weld surface smooth level off, the weld appearance, strengthen the weld should be smooth transition, arc pit should be filled.
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 having reinforced tee joint tensile test report.
7.6 electrode factory certificate.
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