CN109940298B - Composite welding method for different-strength split joints of structural steel for Q370qE and Q690qE bridges - Google Patents
Composite welding method for different-strength split joints of structural steel for Q370qE and Q690qE bridges Download PDFInfo
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Abstract
The invention discloses a composite welding method of different-strength split joints of structural steel for Q370qE and Q690qE bridges in the technical field of welding, wherein grooves are machined on two sides of the split positions of two steel plates, and the two sides of each groove are integrally X-shaped; the bevel angle of the small angle at one side is 29-31 degrees, the bevel angle of the large angle at the other side is 39-41 degrees, and the truncated edge is 1.5-2.5 mm; the ratio of the depth of the small-angle groove to the depth of the large-angle groove is (2-2.5): 1. And welding 2-4 times on one side of the small-angle groove by adopting gas shielded welding to form a backing weld, then fully welding the welding groove by adopting automatic submerged arc welding on the same side of the small-angle groove, turning over the steel plate, carrying out carbon arc gouging and finishing on one side of the large-angle groove, then fully welding the groove by adopting automatic submerged arc welding on the side of the large-angle groove, and finally carrying out heat preservation and slow cooling to normal temperature. The welded joint has excellent mechanical property and good welding quality, and can be used in bridge construction.
Description
Technical Field
The invention relates to a composite welding method for steel plates for bridges with different strengths, belongs to the field of manufacturing of steel bridges, and is suitable for welding split joints of high-strength bridge steels Q370qE and Q690qE with different strengths.
Background
At present, the domestic bridge steel mainly comprises Q345 steel and Q370 steel, Q420 steel and Q500 steel are adopted for parts of components with larger stress of the steel trussed beam, and the bridge steel is developing towards high strength and high performance. The national key plan researches and develops the high-strength steel for bridges in China, looks at the advanced level of the world, firstly puts out the steel Q690qE (the tensile strength is more than or equal to 810 MPa) for the ultra-low carbon bainite high-strength bridges, and is applied to the seven-bridge exemplary engineering in Wuhan Jianghuang Han.
The Wuhan Jianghanhan seven-bridge is a heavy-duty highway bridge with the total length of 672m and 6 bidirectional lanes, and the node plates of the rod pieces at the lower chord part of the pier-top arch ribs on the two sides of the main truss are made of Q690qE high-strength bridge steel. When the lower chord gusset plate and the web plate are designed, butt-joint joints of Q370qE and Q690qE of high-strength steels with different strengths exist, the welding experience of joints with different strengths of Q370qE and Q690qE which are not related in the field of bridge manufacturing can be used for reference, the tensile strength difference of the two high-strength steels exceeds about 200Mpa, great difficulty is brought to both welding material matching and welding process selection, the conventional welding method of the bridge steel is adopted for welding in the existing welding method, but the welding deformation is large, and the welding strength is insufficient. Therefore, the research on the welding process of the high-strength steel joints with different strengths is developed. The research has great economic benefit and social benefit for application of Q690qE in exemplary engineering, and meanwhile, relevant welding experience is accumulated for bridge industry in China.
In view of the above reasons, the invention must control the selection of welding materials, the design of welding grooves, the adjustment of welding process parameters and the like, and weld the splicing heads of the high-strength steels with different strengths of Q370qE and Q690qE, so that the mechanics of the splicing heads of the high-strength steels with different strengths meet the design and standard requirements.
Disclosure of Invention
The invention aims to provide a composite welding method for split joints of structural steel for Q370qE and Q690qE bridges with different strengths, aiming at the defects in the prior art, and the mechanical properties of the welded joints can meet the design requirements.
In order to achieve the purpose, the invention provides a composite welding method for split joints of structural steel for Q370qE and Q690qE bridges with different strengths, which sequentially comprises the following steps:
(1) a groove is machined on the two sides of the butt-jointed part of two steel plates which are made of Q370qE and Q690qE respectively, and the two sides of the groove are X-shaped integrally; the bevel angle of the small angle at one side is 29-31 degrees, the bevel angle of the large angle at the other side is 39-41 degrees, and the truncated edge is 1.5-2.5 mm; the ratio of the depth of the small-angle groove to the depth of the large-angle groove is (2-2.5): 1. Under the angle and the corresponding proportional relation, the high welding strength and the small welding amount can be ensured, and the thermal deformation of the two surfaces of the steel plate can be mutually offset during welding.
(2) Firstly, welding 2-4 times on one side of a small-angle groove by adopting gas shielded welding to form a backing weld, and preheating a steel plate to 70-80 ℃ before welding; the steel plate can be preheated by adopting electromagnetic induction heating equipment.
(3) After the backing weld is finished, raising the temperature of the steel plate to 115-155 ℃, fully welding the welding groove by adopting submerged automatic arc welding at the same side of the small-angle groove, controlling the welding heat input to be 30-35 KJ/cm, and welding by adopting a multilayer and multichannel welding method; in order to prevent cracks from generating, before submerged arc welding is adopted on one side of the small-angle groove, when the plate thickness delta is less than 32mm, the temperature of the steel plate is preferably controlled to be 100 +/-5 ℃; when the thickness of the plate is not less than 32 but delta less than 50mm, the temperature of the steel plate is preferably controlled to be 120 +/-5 ℃; when the thickness delta is more than or equal to 50mm, the temperature of the steel plate is preferably controlled to be 150 +/-5 ℃.
(4) Turning over the steel plate, carrying out carbon arc gouging on one side of the large-angle groove, keeping the depth and the width of the gouging uniform, processing an arc with the thickness of 8mm and the thickness of R being more than or equal to 6mm at the root of the large-angle groove, removing all the truncated edges, finishing one side surface of the large-angle groove, and removing a carburized layer.
(5) And (3) keeping the temperature of the steel plate at 150-200 ℃, adopting submerged automatic arc welding on the side of the large-angle slope, fully welding the slope, controlling the welding heat input at 30-35 KJ/cm, and adopting a multilayer and multichannel welding method to weld.
(6) And after welding, taking heat preservation measures, covering heat preservation cotton for heat preservation, and slowly cooling to the normal temperature.
The invention has the further improvement that the backing weld seam is welded by adopting a solid welding wire, and the solid welding wire comprises the following chemical components in percentage by weight:
C 0.070～0.72%，
Mn 1.5～1.7%，
Si 0.55～0.59%，
S 0.0025～0.035%，
P 0.012～0.014%，
Cr 0.32～0.34%，
Ni 1.01～1.05%，
Cu 0.21～0.25%，
the balance being Fe;
the adopted protective gas comprises the following components in percentage by volume:
CO2 18～22% ，
Ar 78～82%。
the diameter of the solid welding wire is preferably 1.2-1.8 mm. The yield strength Rel 700MPa, the tensile strength Rm 764MPa, the elongation after fracture 22 percent and the low-temperature impact value at minus 40 ℃ of 110J;
the invention is further improved in that the submerged arc welding wire adopted by the submerged arc automatic welding comprises the following chemical components in percentage by weight:
C 0.085～0.095% ，
Mn 1.95～1.99%，
Si 0.05～0.07%，
P 0.01～0.014%，
S 0.0045～0.0055%，
Mo 0.26～0.30%，
Ni 0.96～1%，
Cr 0.26～0.3%，
the balance of Fe,
the diameter of the submerged arc welding wire is 3.8-4.2 mm, the yield strength Rel 630MPa, the tensile strength Rm 720MPa, the elongation after fracture is 25%, and the low-temperature impact value at minus 40 ℃ is 103J; the welding flux is SJ105q, the baking temperature of the welding flux is 350 +/-10 ℃, and the baking time is 1.5-2.5 h.
When multi-layer and multi-pass welding is carried out by adopting submerged arc automatic welding, the temperature of the steel plate between passes is kept at 140-180 ℃.
According to the invention, through a reasonably designed welding groove, welding is carried out by adopting a solid welding wire argon gas shielded welding and submerged arc automatic welding composite welding method, welding of the high-strength steel to the splicing joint with different strengths is finally completed, ultrasonic flaw detection is carried out after welding is completed, and a mechanical property test is carried out after the ultrasonic flaw detection is qualified, wherein the method specifically comprises the following steps:
the blunt edge of the designed X-shaped groove is 1.5-2.5 mm, the back gouging amount of the weld joint can be reduced, so that the deposited metal filling amount of the two sides of the weld joint after back gouging is equivalent, the welding deformation is reduced, the angle of the designed groove is smaller, the welding heat input is reduced, and the flatness of the welded joint steel plates with different strengths is finally ensured.
And adopting solid welding wire mixed gas shielded welding to weld three times on the small-angle slope side, wherein the welding position is a flat position. After the solid welding wire is used for welding three backing welding seams, the temperature of the steel plate can be raised to be more than 150 ℃, and compared with a single method for welding medium and thick plates by adopting submerged arc automatic welding, the method greatly reduces the welding preheating temperature and improves the production efficiency.
A multilayer and multi-pass welding method is adopted, so that impurity elements in the welding wire are prevented from being separated out in the center of a welding seam, and the mechanical property of the welding seam is prevented from being influenced; the base steel sheet: the material is Q370qE and Q690qE respectively, the plate thickness is preferably 32-50 mm, and 3 welding passes are performed by backing weld. When the thickness of the steel plate is 32mm, the mechanical property characteristics of Q690qE are as follows: the yield strength ReL is more than or equal to 690MPa, the tensile strength Rm is more than or equal to 810MPa, the elongation A is more than or equal to 14 percent, and the impact energy of-40 ℃ KV2 is more than or equal to 120J: the Q370qE mechanical property is characterized in that: the yield strength ReL is more than or equal to 370MPa, the tensile strength Rm is more than or equal to 510MPa, the elongation A is more than or equal to 20 percent, and the-40 ℃ KV2 impact energy is more than or equal to 120J.
Properties of the welded joint: the tensile strength of the butt-spliced joint of the welding seam is 556MPa, and the fracture position is the side of low material Q370 qE; the yield strength of the welding line is 708MPa, the tensile strength of the welding line is 759MPa, and the elongation after fracture is 25; three-zone maximum hardness HV of welded joint10319, the-40 ℃ low-temperature impact values of the welding line are 123J, 132J and 150J respectively; the-40 ℃ low-temperature impact values of a heat affected zone of Q370qE are 225J, 227J and 204J respectively; the-40 ℃ low-temperature impact values of a Q690qE side heat affected zone are 245J, 246J and 219J respectively; no crack is found in the bending test of the splicing joint; the high-strength steel welded joint has good mechanical property, can meet the requirements of design and related standards, has larger allowance for low-temperature impact of a welding seam and a heat affected zone, and has hardness of three zones of the welding seam which is less than HV10 380, no hardened structure was produced.
The preheating is carried out by adopting electromagnetic induction heating equipment, and the heating temperature is 70-80 ℃. By adopting the electromagnetic induction heating equipment, the steel plate can be fully preheated, and the central position of the steel thickness and the surface of the steel plate can meet the process requirements.
The inter-channel temperature in the welding process is kept at 140-180 ℃; micro alloy elements are added into the high-strength steel plate Q690qE, and the temperature between welding tracks should be strictly controlled to avoid burning loss of the alloy elements.
Compared with the prior art, the invention has the following advantages:
according to the invention, a proper welding material combination is selected, and the welding of the split joint with different strengths of the high-strength bridge steel Q370qE and Q690qE with the tensile strength difference larger than 300Mpa is realized for the first time. Firstly, the strength of weld metal is considered, a combination of a solid welding wire and a submerged arc welding wire is selected, the tensile strength of deposited metal is between Q370qE and Q690qE, the medium strength matching principle is adopted, a layer of transition weld with medium strength is formed between two base materials with different strengths, alloy elements in the deposited metal reinforce chemical components on the Q370qE side, the mechanical property of a weld fusion area on the Q370qE side is improved, meanwhile, the alloy elements on the Q690qE side are not diluted, the mechanical property of the weld fusion area on the Q690qE side is maintained, and therefore the mechanical property of the whole weld area is guaranteed. Secondly, considering that the low-temperature impact requirements of two joints with different strengths are both-40 ℃, the selected solid welding wire and submerged arc welding wire are combined, and a certain amount of nickel element is added into deposited metal, so that the low-temperature impact performance at-40 ℃ is good. The selected welding material has both combination strength and low-temperature impact toughness, and is an ideal material for welding joints of Q370qE steel and Q690qE steel with different strengths.
According to the provisions of GB 4675.1 'weldability test inclined Y-shaped groove welding crack test method', the invention performs test small iron grinding and large iron grinding tests on 32mm and 50mm steel plates, wherein the welding material of the small iron grinding test is a solid welding wire and the diameter of the welding material is phi 1.2. The welding material for the large iron grinding test is a submerged arc welding wire with the diameter of phi 4.0. After 2-4 backing weld seams are backing welded, the interlayer temperature can reach 150 ℃, the preheating temperature of Q690qE steel is greatly reduced, the preheating temperature is reduced to 70-80 ℃, the delayed cracks of the weld seams can be prevented, the production efficiency can be improved, and the method has excellent manufacturability and practicability.
After the selected welding material combination is used for welding the Q370qE and Q690qE butt joints with different strengths, all mechanical properties can meet the standard and design requirements, meanwhile, the strengths of a welding seam and a heat affected zone are higher than the strength of a Q370qE base metal, the tensile fracture position of the welding seam joint is the side of a low-material Q370qE base metal, and the welding seam joint is not fractured at a stress concentration point and a welding seam weak position of the butt joint, so that the welding material combination has better safety when being used for the joints with different strengths of Q370qE and Q690qE in bridge engineering.
The X-shaped groove is adopted, the truncated edge is 2mm, the back chipping workload of the large-angle groove is reduced, the cross section area of a welding line is greatly reduced while the operability is ensured, the heat input is reduced, and the control of welding deformation is facilitated.
The technical scheme of the invention is established on the basis of welding process evaluation, and the invention can achieve good mechanical property of a welding joint, high-efficiency welding and strong practicability in the implementation process. Therefore, the invention has important significance for welding the splicing joint with different strengths of the high-strength bridge steel.
Drawings
FIG. 1 is a schematic diagram of a groove structure corresponding to a splicing part in example 1.
FIG. 2 is a schematic view of a welding sequence at a welding seam, wherein 1 and 3 are schematic views of submerged arc welding positions, and 2 is a schematic view of a backing weld position.
Detailed Description
Example 1
The thickness of the welded steel plate is 32mm, the materials are respectively Q370qE and Q690qE, and the welding is carried out according to the following steps in sequence:
(1) as shown in a schematic diagram of a butt-jointed groove structure in fig. 1, grooves are machined on both sides of the butt-jointed part of two steel plates, and the whole of both sides of each groove is in an X shape; the angle of the small-angle groove on one side is 30 degrees, the small-angle groove between the two steel plates integrally forms a 60-degree included angle, the angle of the large-angle groove on the other side is 40 degrees, the large-angle groove between the two steel plates integrally forms a 80-degree included angle, and the truncated edge is 2 mm; the ratio of the depth of the small-angle groove to the depth of the large-angle groove is 2:1, the depth of the small-angle groove is 20mm, and the depth of the large-angle groove is 10 mm.
(2) Heating by adopting electromagnetic induction heating equipment before welding, wherein the heating temperature is 70-80 ℃, and welding 3 backing weld seams on one side of the small-angle groove by adopting gas shielded welding as shown in figure 2;
the welding material is a solid welding wire with the diameter of 1.2 mm; the volume content of the protective gas is 20% CO2+80% Ar. The welding current is 240-260A, the welding voltage is 25-28V, and the welding speed is 280-320 mm/min.
(3) After the backing weld is finished, raising the temperature of the steel plate to 115-155 ℃, fully welding the welding groove by adopting submerged automatic arc welding at the same side of the small-angle groove, controlling the welding heat input to be 30-35 KJ/cm, and welding by adopting a multilayer and multichannel welding method; the welding material is a submerged-arc welding wire with the diameter of 4.0mm, SJ105Q welding flux is matched, the welding current is 630-660A, the welding voltage is 29-31V, the welding speed is 360-400 mm/min, and a multi-layer and multi-pass welding method is adopted for welding during welding;
(4) turning over a steel plate, gouging and back gouging on a large-angle slope side, performing carbon arc gouging by adopting a carbon rod with the diameter of 5mm, wherein the depth and the width of a gouging groove are kept uniform and consistent, an arc with the diameter of R =6mm is formed at the root part, removing all blunt edges, trimming the surface by adopting an angular polisher, and removing a carburized layer;
(5) keeping the temperature of a steel plate at 150-200 ℃, adopting submerged arc automatic welding on the side of a large-angle slope, fully welding the slope, controlling the welding heat input at 30-35 KJ/cm, adopting a submerged arc welding wire as a welding material, wherein the diameter of the submerged arc welding wire is 4.0mm, matching SJ105Q welding flux, the welding current is 630-660A, the welding voltage is 29-31V, and the welding speed is 360-400 mm/min; when welding, a multilayer and multi-pass welding method is adopted for welding;
(6) after welding, heat preservation is carried out by adopting heat preservation cotton, and the steel plate is slowly cooled to room temperature, so that a hardening structure caused by high cooling speed is avoided.
When multi-layer and multi-pass welding is carried out by adopting submerged arc automatic welding, the temperature of the steel plate between passes is kept at 140-180 ℃.
After appearance inspection and nondestructive detection, the appearance quality of the welding joint meets the requirement of 4.9.12 in Q/CR 9211-.
The backing weld seam is welded by adopting a solid welding wire, and the solid welding wire comprises the following chemical components in percentage by weight:
C 0.071%，
Mn 1.6%，
Si 0.57%，
S 0.003%，
P 0.013%，
Cr 0.34%，
Ni 1.03%，
Cu 0.23%，
the balance being Fe;
the adopted protective gas comprises the following components in percentage by volume:
80% of Ar and the gas purity is more than or equal to 99.9%.
The submerged arc welding wire adopted by the submerged arc automatic welding comprises the following chemical components in percentage by weight:
C 0.09% ，
Mn 1.97%，
Si 0.06%，
P 0.012%，
S 0.005%，
Mo 0.28%，
Ni 0.98%，
Cr 0.28%，
the balance of Fe,
the diameter of the submerged arc welding wire is 4.0mm, the welding flux is SJ105q, the baking temperature of the welding flux is 350 ℃, and the baking time is 2 h.
Example 2
The method for compositely welding the split joints of the bridge structural steel with the plate thickness of 50mm, which is Q370qE and Q690qE, with different strengths sequentially comprises the following steps:
(1) a groove is machined on the two sides of the butt-jointed part of two steel plates which are made of Q370qE and Q690qE respectively, and the two sides of the groove are X-shaped integrally; the bevel angle of the small angle at one side is 31 degrees, the bevel angle of the large angle at the other side is 41 degrees, and the truncated edge is 2.5 mm; the ratio of the depth of the small-angle groove to the depth of the large-angle groove is 2.5: 1;
(2) firstly, welding 3 times on one side of a small-angle groove by adopting gas shielded welding to form a backing weld, and preheating a steel plate to 70-80 ℃ before welding;
(3) after the backing weld is finished, raising the temperature of the steel plate to 115-155 ℃ by welding heat, fully welding the welding groove by adopting submerged arc automatic welding at the same side of the small-angle groove, controlling the welding heat input at 30-35 KJ/cm, and welding by adopting a multi-layer and multi-channel welding method; before adopting submerged-arc welding on one side of the small-angle groove, carrying out submerged-arc welding when controlling the temperature of the steel plate to be 150 +/-5 ℃;
(4) turning over the steel plate, carrying out carbon arc gouging on one side of the large-angle groove, keeping the depth and the width of the gouging uniform, processing an arc with the diameter of R =8mm at the root of the large-angle groove, removing all the truncated edges, finishing the surface of one side of the large-angle groove, and removing a carburized layer;
(5) keeping the temperature of the steel plate at 150-200 ℃, adopting submerged automatic arc welding on the side of the large-angle slope, fully welding the slope, controlling the welding heat input at 30-35 KJ/cm, and adopting a multilayer and multichannel welding method to weld;
(6) and after welding, taking heat preservation measures, covering heat preservation cotton for heat preservation, and slowly cooling to the normal temperature.
The backing weld seam is welded by adopting a solid welding wire, and the solid welding wire comprises the following chemical components in percentage by weight:
C 0.070%，
Mn 1.7%，
Si 0.55%，
S 0.035%，
P 0.012%，
Cr 0.34%，
Ni 1.01%，
Cu 0.25%，
the balance being Fe;
the adopted protective gas comprises the following components in percentage by volume:
CO2 22% ，
Ar 78%。
the gas purity is more than or equal to 99.9 percent.
The submerged arc welding wire adopted by the submerged arc automatic welding comprises the following chemical components in percentage by weight:
C 0.085% ，
Mn 1.99%，
Si 0.05%，
P 0.014%，
S 0.0045%，
Mo 0.30%，
Ni 0.96%，
Cr 0.3%，
the balance of Fe,
the diameter of the submerged arc welding wire is 4.2mm, the welding flux is SJ105q, the baking temperature of the welding flux is 350 +/-10 ℃, and the baking time is 2.5 h. The submerged arc welding current is 630-660A, the welding voltage is 29-31V, and the welding speed is 360-400 mm/min. The diameter of the solid welding wire is 1.2mm, the welding current is 240-260A, the welding voltage is 25-28V, and the welding speed is 280-320 mm/min.
And (4) the welding test plate is qualified by ultrasonic flaw detection. The mechanical properties of the welding joint are as follows: the tensile strength of the welded joint is 574MPa, the welded joint is broken on the Q370qE side of the low material, and the elongation after breakage is 24.5; the highest hardness HV10 of the three zones of the welding joint is 345; the-40 ℃ low-temperature impact values of the welding seam are respectively 114J, 121J and 111J; the-40 ℃ low-temperature impact values of a heat affected zone of Q370qE are 203J, 224J and 236J respectively; the-40 ℃ low-temperature impact values of a heat affected zone Q690qE are 208J, 177J and 159J respectively; no crack is found in the bending test of the splicing joint; the surface of the plate is flat and has no local buckling deformation.
The invention selects proper welding material combination and adopts a welding method of solid welding wire mixed gas shielded welding and submerged arc welding to weld the welding joints with different strengths of Q370qE and Q690qE, the external forming of the welding seam is beautiful, the internal performance of the welding seam is reliable, and the quality of the welding seam is stable. After appearance inspection and nondestructive detection, the appearance quality of the welding joint meets the requirement of 4.9.12 in Q/CR 9211-. The tensile strength of the welded joint is 550-570MPa, the tensile fracture and the low-material base metal side of the joint are achieved, the-40 ℃ low-temperature impact energy of the welded joint and the heat affected zone is 111-246J, and the low-temperature toughness of the welded joint has abundant reserves and meets the requirements of standards and designs.
Example 3
The method for compositely welding the split joints of the bridge structural steel with the plate thickness of 50mm, which is Q370qE and Q690qE, with different strengths sequentially comprises the following steps:
(1) a groove is machined on the two sides of the butt-jointed part of two steel plates which are made of Q370qE and Q690qE respectively, and the two sides of the groove are X-shaped integrally; the bevel angle of the small angle at one side is 29-31 degrees, the bevel angle of the large angle at the other side is 39-41 degrees, and the truncated edge is 2.5 mm; the ratio of the depth of the small-angle groove to the depth of the large-angle groove is 2.5: 1;
(2) firstly, welding 3 times on one side of a small-angle groove by adopting gas shielded welding to form a backing weld, and preheating a steel plate to 70-80 ℃ before welding;
(3) after the backing weld is finished, raising the temperature of the steel plate to 115-155 ℃ by welding heat, fully welding the welding groove by adopting submerged arc automatic welding at the same side of the small-angle groove, controlling the welding heat input at 30-35 KJ/cm, and welding by adopting a multi-layer and multi-channel welding method; before adopting submerged-arc welding on one side of the small-angle groove, carrying out submerged-arc welding when controlling the temperature of the steel plate to be 150 +/-5 ℃;
(4) turning over the steel plate, carrying out carbon arc gouging on one side of the large-angle groove, keeping the depth and the width of the gouging uniform, processing an arc with the diameter of R =8mm at the root of the large-angle groove, removing all the truncated edges, finishing the surface of one side of the large-angle groove, and removing a carburized layer;
(5) keeping the temperature of the steel plate at 150-200 ℃, adopting submerged automatic arc welding on the side of the large-angle slope, fully welding the slope, controlling the welding heat input at 30-35 KJ/cm, and adopting a multilayer and multichannel welding method to weld;
(6) and after welding, taking heat preservation measures, covering heat preservation cotton for heat preservation, and slowly cooling to the normal temperature.
The backing weld seam is welded by adopting a solid welding wire, and the solid welding wire comprises the following chemical components in percentage by weight:
C 0.72%，
Mn 1.5%，
Si 0.59%，
S 0.0025%，
P 0.014%，
Cr 0.32%，
Ni 1.05%，
Cu 0.21%，
the balance being Fe;
the adopted protective gas comprises the following components in percentage by volume:
CO2 18% ，
Ar 82%。
the gas purity is more than or equal to 99.9 percent.
The submerged arc welding wire adopted by the submerged arc automatic welding comprises the following chemical components in percentage by weight:
C 0.095% ，
Mn 1.95%，
Si 0.07%，
P 0.01%，
S 0.0055%，
Mo 0.26%，
Cr 0.26%，
the balance of Fe,
the diameter of the submerged arc welding wire is 3.8mm, the welding flux is SJ105q, the baking temperature of the welding flux is 350 +/-10 ℃, and the baking time is 1.5 h. The submerged arc welding current is 630-660A, the welding voltage is 29-31V, and the welding speed is 360-400 mm/min. The diameter of the solid welding wire is 1.2mm, the welding current is 240-260A, the welding voltage is 25-28V, and the welding speed is 280-320 mm/min.
After appearance inspection and nondestructive detection, the appearance quality of the welding joint meets the requirement of 4.9.12 in Q/CR 9211-.
Example 4
The composite welding method for the split joints of the structural steel for the Q370qE bridge and the Q690qE bridge with different strengths comprises the following steps of:
(1) a groove is machined on the two sides of the butt-jointed part of two steel plates which are made of Q370qE and Q690qE respectively, and the two sides of the groove are X-shaped integrally; the bevel angle of the small angle at one side is 29-31 degrees, the bevel angle of the large angle at the other side is 39-41 degrees, and the truncated edge is 1.5-2.5 mm; the ratio of the depth of the small-angle groove to the depth of the large-angle groove is (2-2.5): 1;
(2) firstly, welding 2-4 times on one side of a small-angle groove by adopting gas shielded welding to form a backing weld, and preheating a steel plate to 70-80 ℃ before welding;
(3) after the backing weld is finished, raising the temperature of the steel plate to 115-155 ℃, fully welding the welding groove by adopting submerged automatic arc welding at the same side of the small-angle groove, controlling the welding heat input to be 30-35 KJ/cm, and welding by adopting a multilayer and multichannel welding method;
(4) turning over the steel plate, carrying out carbon arc gouging on one side of the large-angle groove, keeping the depth and the width of the gouging uniform, processing an arc with the thickness of 8mm or more and the thickness of R or more and 6mm or more at the root of the large-angle groove, removing all truncated edges, finishing the surface of one side of the large-angle groove, and removing a carburized layer;
(5) keeping the temperature of the steel plate at 150-200 ℃, adopting submerged automatic arc welding on the side of the large-angle slope, fully welding the slope, controlling the welding heat input at 30-35 KJ/cm, and adopting a multilayer and multichannel welding method to weld;
(6) and after welding, taking heat preservation measures, covering heat preservation cotton for heat preservation, and slowly cooling to the normal temperature.
In order to prevent cracks from being generated, before submerged arc welding is adopted on one side of the small-angle groove, when the plate thickness delta is less than 32mm, the temperature of the steel plate is controlled to be 100 +/-5 ℃; when the thickness of the plate is not less than 32 and delta is less than 50mm, controlling the temperature of the steel plate to be 120 +/-5 ℃; when the thickness delta of the plate is more than or equal to 50mm, the temperature of the steel plate is controlled to be 150 +/-5 ℃.
And 3 welding backing weld joints when the thickness of the welded steel plate is 32-50 mm.
The backing weld seam is welded by adopting a solid welding wire, and the solid welding wire comprises the following chemical components in percentage by weight:
C 0.070～0.72%，
Mn 1.5～1.7%，
Si 0.55～0.59%，
S 0.0025～0.035%，
P 0.012～0.014%，
Cr 0.32～0.34%，
Ni 1.01～1.05%，
Cu 0.21～0.25%，
the balance being Fe;
the adopted protective gas comprises the following components in percentage by volume:
CO2 18～22% ，
Ar 78～82%。
5. the composite welding method for the split joint of the structural steel for the bridge Q370qE and Q690qE with different strengths as claimed in claim 3, wherein the diameter of the solid welding wire is 1.2-1.8 mm.
The submerged arc welding wire adopted by the submerged arc automatic welding comprises the following chemical components in percentage by weight:
C 0.085～0.095% ，
Mn 1.95～1.99%，
Si 0.05～0.07%，
P 0.01～0.014%，
S 0.0045～0.0055%，
Mo 0.26～0.30%，
Ni 0.96～1%，
Cr 0.26～0.3%，
the balance of Fe,
the diameter of the submerged arc welding wire is 3.8-4.2 mm, the welding flux is SJ105q, the baking temperature of the welding flux is 350 +/-10 ℃, and the baking time is 1.5-2.5 h.
When multi-layer and multi-pass welding is carried out by adopting submerged arc automatic welding, the temperature of the steel plate between passes is kept at 140-180 ℃.
The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.
Claims (8)
1. A welding method for composite welding of structural steel heterogeneous butt joints for Q370qE and Q690qE bridges is characterized by sequentially comprising the following steps:
(1) a groove is machined on the two sides of the butt joint of the two steel plates which are made of Q370qE and Q690qE respectively, and the two sides of the groove are X-shaped integrally; the bevel angle of the small angle at one side is 29-31 degrees, the bevel angle of the large angle at the other side is 39-41 degrees, and the truncated edge is 1.5-2.5 mm; the ratio of the depth of the small-angle groove to the depth of the large-angle groove is (2-2.5): 1;
(2) firstly, welding 2-4 times on one side of a small-angle groove by adopting gas shielded welding to form a backing weld, and preheating a steel plate to 70-80 ℃ before welding;
the backing weld seam is welded by adopting a solid welding wire, and the solid welding wire comprises the following chemical components in percentage by weight:
C 0.070～0.72%，
Mn 1.5～1.7%，
Si 0.55～0.59%，
S 0.0025～0.035%，
P 0.012～0.014%，
Cr 0.32～0.34%，
Ni 1.01～1.05%，
Cu 0.21～0.25%，
the balance being Fe;
the adopted protective gas comprises the following components in percentage by volume:
CO2 18～22% ，
Ar 78～82%；
(3) after the backing weld is finished, raising the temperature of the steel plate to 115-155 ℃, fully welding the welding groove by adopting submerged automatic arc welding at the same side of the small-angle groove, controlling the welding heat input to be 30-35 KJ/cm, and welding by adopting a multilayer and multichannel welding method;
the submerged arc welding wire adopted by the submerged arc automatic welding comprises the following chemical components in percentage by weight:
C 0.085～0.095% ，
Mn 1.95～1.99%，
Si 0.05～0.07%，
P 0.01～0.014%，
S 0.0045～0.0055%，
Mo 0.26～0.30%，
Ni 0.96～1%，
Cr 0.26～0.3%，
the balance of Fe,
the diameter of the submerged arc welding wire is 3.8-4.2 mm, the welding flux is SJ105q, the baking temperature of the welding flux is 350 +/-10 ℃, and the baking time is 1.5-2.5 h;
(4) turning over the steel plate, carrying out carbon arc gouging on one side of the large-angle groove, keeping the depth and the width of the gouging uniform, processing an arc with the thickness of 8mm or more and the thickness of R or more and 6mm or more at the root of the large-angle groove, removing all truncated edges, finishing the surface of one side of the large-angle groove, and removing a carburized layer;
(5) keeping the temperature of the steel plate at 150-200 ℃, adopting submerged automatic arc welding on the side of the large-angle slope, fully welding the slope, controlling the welding heat input at 30-35 KJ/cm, and adopting a multilayer and multichannel welding method to weld;
(6) and after welding, taking heat preservation measures, covering heat preservation cotton for heat preservation, and slowly cooling to the normal temperature.
2. The welding method of the dissimilar butt joint compound welding of the structural steel for the bridge Q370qE and Q690qE as claimed in claim 1, wherein the temperature of the steel plate is controlled to 100 ± 5 ℃ when the plate thickness delta is less than 32mm before submerged arc welding is adopted on the side of the small angle groove for preventing the generation of cracks; when the thickness of the plate is not less than 32 and delta is less than 50mm, controlling the temperature of the steel plate to be 120 +/-5 ℃; when the thickness delta of the plate is more than or equal to 50mm, the temperature of the steel plate is controlled to be 150 +/-5 ℃.
3. The welding method for the dissimilar butt joint composite welding of the structural steels for the Q370qE and Q690qE bridge girder according to claim 1, wherein the thickness of the welded steel plate is 32-50 mm, and 3 welding passes are performed on the backing weld.
4. The welding method of the dissimilar butt joint composite welding of the structural steel for the Q370qE and Q690qE bridge of claim 1, wherein the backing weld is welded by using a solid welding wire, and the solid welding wire comprises the following chemical components in percentage by weight:
C 0.071%，
Mn 1.6%，
Si 0.57%，
S 0.003%，
P 0.013%，
Cr 0.34%，
Ni 1.03%，
Cu 0.23%，
the balance being Fe;
the adopted protective gas comprises the following components in percentage by volume:
CO2 20% ，
80% of Ar and the gas purity is more than or equal to 99.9%.
5. The welding method of the Q370qE and Q690qE bridge structural steel dissimilar butt joint composite welding according to claim 4, wherein the diameter of the solid welding wire is 1.2-1.8 mm.
6. The welding method for the dissimilar butt joint composite welding of the structural steel for the Q370qE and Q690qE bridge according to claim 1, wherein the submerged arc welding wire adopted by the submerged arc automatic welding comprises the following chemical components in percentage by weight:
C 0.09% ，
Mn 1.97%，
Si 0.06%，
P 0.012%，
S 0.005%，
Mo 0.28%，
Ni 0.98%，
Cr 0.28%，
the balance of Fe,
the diameter of the submerged arc welding wire is 4.0, the welding flux is SJ105q, the baking temperature of the welding flux is 350 ℃, and the baking time is 2 hours.
7. The welding method for the dissimilar butt joint composite welding of the structural steel for the Q370qE and Q690qE bridge girder according to claim 6, wherein the steel plate temperature is kept between paths at 140-180 ℃ when multi-layer multi-path welding is carried out by adopting the submerged arc automatic welding.
8. The welding method for the dissimilar butt joint composite welding of the structural steels for the bridge Q370qE and Q690qE as claimed in any one of claims 1 to 7, wherein the steel plates are preheated by heating with a crawler-type heating pad.
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| CN110732748B (en) * | 2019-09-16 | 2021-11-26 | 广州文冲船厂有限责任公司 | Rectangular cylinder welding method |
| CN110666301A (en) * | 2019-09-16 | 2020-01-10 | 中铁九桥工程有限公司 | Q420qE + Q690qENH dissimilar material composite welding butt joint method |
| CN110802312B (en) * | 2019-11-15 | 2021-06-22 | 中铁宝桥集团有限公司 | Welding method for horizontal butt joint of Q370qD and Q500qE bridge steel |
| CN113319403B (en) * | 2021-06-07 | 2023-06-30 | 中国建筑一局(集团)有限公司 | Welding construction method for ultra-thick plate |
| CN115519216B (en) * | 2022-09-21 | 2023-09-05 | 中铁宝桥（扬州）有限公司 | Welding deformation control method for large-sized steel tower block with open type asymmetric section |
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