Welding process of marine atmosphere corrosion resistant steel plate

Abstract

The invention discloses a welding process of a marine atmosphere corrosion resistant steel plate, which comprises the following steps of: aiming at plate butt joint, adopting a groove form with a V-shaped groove, a truncated edge size of 2mm and a groove angle of 30 degrees, adopting flux-cored wire CO2 gas shielded semi-automatic welding to carry out backing welding or submerged-arc welding to carry out filling and cosmetic welding, and carrying out back gouging treatment before reverse welding; for T-shaped penetration fillet welds and T-shaped partial penetration fillet welds, a groove form with a K-shaped groove, a truncated edge size of 2mm and a groove angle of 45 degrees is adopted, and flux-cored wire CO2 gas shield semi-automatic welding is adopted; for T-shaped fillet weld ship position welding, grooves are not formed, and submerged automatic arc welding is adopted; aiming at T-shaped fillet weld flat position welding, no groove is formed, and flux-cored wire CO2 gas shielded semi-automatic welding is adopted. According to the process, the requirement that the mechanical property of a welding joint of the marine atmospheric corrosion resistant steel is not lower than that of base metal is met, meanwhile, the corrosion resistance of a welding seam is equivalent to that of the base metal, and the requirement for corrosion resistance of components in the marine atmospheric environment is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel structure bridge welding process, in particular to a welding process of marine atmospheric corrosion resistant steel plate. BACKGROUND

[0002] Marine atmospheric corrosion resistant steel is a special steel material specially used for resisting marine environment corrosion, which is widely used in marine engineering fields such as cross-sea bridge, offshore platform, ship, port facility, etc., and can significantly improve the service life and safety of the structure. It adds alloy elements such as Cu, Cr, Ni, Mo on the basis of ordinary carbon steel to enhance the resistance to corrosion factors such as chloride ions, high humidity in marine atmosphere. In the steel structure of the bridge, marine atmospheric corrosion resistant steel not only needs to meet the requirements of mechanical properties and corrosion resistance, but also needs to consider the requirements of fatigue performance under dynamic load, and also needs to consider that the corrosion resistance of the weld and the base material is equivalent under the corrosion condition, so as to avoid the adverse effects of the difference in corrosion degree on the fatigue performance of the component.

[0003] Ordinary weathering steel can resist atmospheric corrosion, while marine atmospheric corrosion resistant steel needs to meet the corrosion resistance in high chloride ion environment. In the marine atmospheric environment, its corrosion resistance is 2-8 times that of ordinary carbon steel, which can effectively prevent chloride ion penetration and corrosion, and form a dense and stable rust layer (such as α-FeOOH) on the surface to prevent further corrosion of the corrosion medium. At the same time, it also has good mechanical properties, which can meet the requirements of strength and toughness of marine engineering materials, and can adapt to harsh marine atmospheric environment with high temperature, high humidity and high salt. Therefore, how to meet the requirements that the mechanical properties of the welded joint are not lower than those of the base material, and the corrosion resistance of the weld is equivalent to that of the base material, and meet the requirements of the component corrosion resistance in marine atmospheric environment is a difficult problem in the welding practice of marine atmospheric corrosion resistant steel. SUMMARY

[0004] In order to realize the requirements that the mechanical properties of the welded joint of marine atmospheric corrosion resistant steel are not lower than those of the base material, and the corrosion resistance of the weld is equivalent to that of the base material, and meet the requirements of the component corrosion resistance in marine atmospheric environment, the present application provides a welding process of marine atmospheric corrosion resistant steel plate.

[0005] The technical scheme adopted by the present application to realize the above technical effects is: A welding process of marine atmospheric corrosion resistant steel plate is applied to the welding of marine atmospheric corrosion resistant steel plate, wherein: For the butt joint of the plate, a V-shaped groove with a root face size of 2mm and a groove angle of 30° is used, and a flux-cored wire CO2 gas protection semi-automatic welding is used for backing welding or submerged arc welding for filling and cap welding, and the back welding is cleaned before welding. For the welding joint of T-type fillet weld and T-type partial penetration fillet weld, a K-shaped groove is adopted, the size of the blunt edge is 2mm, the groove angle is 45°, and CO2 gas protection semi-automatic welding of flux-cored wire is adopted; For the welding joint of T-type fillet weld and T-type partial penetration fillet weld, a K-shaped groove is adopted, the size of the blunt edge is 2mm, the groove angle is 45°, and CO2 gas protection semi-automatic welding of flux-cored wire is adopted; For the welding joint of T-type fillet weld and T-type partial penetration fillet weld, a K-shaped groove is adopted, the size of the blunt edge is 2mm, the groove angle is 45°, and CO2 gas protection semi-automatic welding of flux-cored wire is adopted; The chemical composition of the deposited metal of the flux-cored wire is: C:≤0.08, Si:0.10-0.50, Mn:0.50-1.30, P:≤0.025, S:≤0.015, Mo:0.10-0.40, Ti:≤0.08, Ni:1.30-2.00, Cu:0.30-0.60; the chemical composition of the deposited metal of the submerged arc welding wire and the submerged arc welding agent is: C:≤0.08, Si:0.10-0.50, Mn:0.50-1.30, P:≤0.025, S:≤0.015, Mo:0.10-0.40, Ti:≤0.08, Ni:1.30-2.00, Cu:0.30-0.60.

[0006] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, the chemical composition of the submerged arc welding agent is: P:≤0.060, S:≤0.030.

[0007] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, the welding heat input control range of the CO2 gas protection semi-automatic welding of flux-cored wire is: ≤30.8kJ / cm; the welding heat input control range of the submerged arc automatic welding is: ≤59.1kJ / cm.

[0008] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, the pre-welding preheating temperature is determined according to different plate thicknesses, and the determination rule is: When the plate thickness is ≤28mm, the pre-welding preheating temperature is ≥5℃; When the plate thickness is 28-40mm, the pre-welding preheating temperature is 80-120℃.

[0009] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, the interpass temperature is not more than 200℃.

[0010] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, for the butt joint of the plate, the welding process parameters of the CO2 gas protection semi-automatic welding of flux-cored wire for the backing welding are: welding current 240-260A, arc voltage 28-30V, welding speed 12-20m / h, heat input 12.1-23.4kJ / cm; The welding process parameters for the filling and covering welding by submerged arc welding are: welding current 630-690 A, arc voltage 28-34 V, welding speed 20-26 m / h, heat input 24.4-42.2 kJ / cm.

[0011] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, for the welding joint of T-type partial penetration fillet weld horizontal position welding, the welding process parameters of the flux-cored wire CO2 gas shielded semi-automatic welding are: welding current 180-200 A, arc voltage 26-28 V, welding speed 7-9 m / h, heat input 18.8-28.7 kJ / cm.

[0012] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, for the welding joint of T-type partial penetration fillet weld horizontal position welding, the welding process parameters of the flux-cored wire CO2 gas shielded semi-automatic welding are: welding current 180-200 A, arc voltage 26-28 V, welding speed 7-9 m / h, heat input 18.8-28.7 kJ / cm.

[0013] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, for the welding joint of T-type fillet weld horizontal position welding, the welding process parameters of the flux-cored wire CO2 gas shielded semi-automatic welding are: welding current 240-280 A, arc voltage 28-32 V, welding speed 16-24 m / h, heat input 10.1-20.2 kJ / cm.

[0014] Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, for the welding joint of T-type fillet weld horizontal position welding, the welding process parameters of the flux-cored wire CO2 gas shielded semi-automatic welding are: welding current 240-280 A, arc voltage 28-32 V, welding speed 16-24 m / h, heat input 10.1-20.2 kJ / cm. Preferably, in the welding process of the marine atmosphere corrosion resistant steel plate, for the welding joint of T-type fillet weld horizontal position welding, the welding process parameters of the flux-cored wire CO2 gas shielded semi-automatic welding are: welding current 240-280 A, arc voltage 28-32 V, welding speed 16-24 m / h, heat input 10.1-20.2 kJ / cm.

[0015] The beneficial effects of the present application are: the present application adopts the groove form, welding method and welding process parameters for different welding joint forms and plate thicknesses of the marine atmospheric corrosion resistant steel, and takes into account the low temperature impact toughness, weather resistance and welding efficiency of the welding joint, and has strong practicability. The cladding metal formed by the welding material contains elements such as Cu, Cr, Ni and Mo that can improve the weather resistance of the weld, and has similar chemical composition to the base material, the weather resistance alloy index V is greater than or equal to 1.29, the weather resistance is not lower than the base material, and the purity is relatively high, the weld structure is mainly fine acicular ferrite, and has strong toughness. The present application has important role in promoting the development of the weathering steel bridge in the marine climate environment corrosion, and can be applied to the construction of the bridge structure, and can be applied to the welding of other weathering steels, and has strong applicability. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a joint and groove form schematic diagram of the first embodiment of the present application; Figure 2 is a welding bead arrangement schematic diagram of the first embodiment of the present application; Figure 3 is a joint and groove form schematic diagram of the second embodiment of the present application; Figure 4 is a welding bead arrangement schematic diagram of the second embodiment of the present application; Figure 5 is a joint and groove form schematic diagram of the third embodiment of the present application; Figure 6 is a welding bead arrangement schematic diagram of the third embodiment of the present application; Figure 7 is a joint and groove form schematic diagram of the fourth embodiment of the present application; Figure 8 is a welding bead arrangement schematic diagram of the fourth embodiment of the present application; Figure 9 is a joint form schematic diagram of the fifth, sixth and seventh embodiments of the present application; Figure 10 is a welding bead arrangement schematic diagram of the fifth embodiment of the present application; Figure 11 is a welding bead arrangement schematic diagram of the sixth embodiment of the present application; Figure 12 is a welding bead arrangement schematic diagram of the seventh embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to further understand the present application, the present application will be further described below with reference to the drawings and specific embodiments of the specification: The model of the marine bridge corrosion resistant steel plate mentioned in the present application is Q345qDNHY-I, the chemical components of which are listed in Table 1, and the mechanical properties are listed in Table 2. Specifically, the chemical components are C: 0.03-0.06, Si: 0.15-0.30, Mn: 0.80-1.00, S: ≤0.003, P: ≤0.015, Ni: 1.30-1.35, Cu: 0.45-0.50, Mo: 0.20-0.30, Nb: 0.01-0.03, Al: 0.02-0.05, Ti: 0.01-0.02. The balance is Fe and incidental impurities, and the weathering alloy index V is ≥1.29. It should be noted that in the embodiments of the present application, the end point values of the range symbol "~" are within the value range.

[0018] Table 1 Chemical components of the marine atmospheric corrosion resistant steel Q345qDNHY-I steel plate

[0019] Table 2 Mechanical properties of the marine atmospheric corrosion resistant steel Q345qDNHY-I steel plate

[0020] In the present application, the welding process of the marine bridge corrosion resistant steel plate is as follows: For the butt joint of the plate, a V-shaped groove with a root face size of 2mm and a groove angle of 30° is used, and a CO2 gas protection semi-automatic welding with a flux-cored wire is used for backing welding or a submerged arc welding is used for filling and surface welding, and the back welding is cleaned before welding; For the T-shaped penetration angle weld and the T-shaped partial penetration angle weld, a K-shaped groove with a root face size of 2mm and a groove angle of 45° is used, and a CO2 gas protection semi-automatic welding with a flux-cored wire is used; For the T-shaped fillet weld, no groove is used, and a submerged arc automatic welding is used; For the T-shaped fillet weld, no groove is used, and a CO2 gas protection semi-automatic welding with a flux-cored wire is used; The chemical composition of the flux-cored wire cladding metal is: C:≤0.08, Si:0.10-0.50, Mn:0.50-1.30, P:≤0.025, S:≤0.015, Mo:0.10-0.40, Ti:≤0.08, Ni:1.30-2.00, Cu:0.30-0.60; the chemical composition of the submerged arc welding wire and the submerged arc welding agent cladding metal is: C:≤0.08, Si:0.10-0.50, Mn:0.50-1.30, P:≤0.025, S:≤0.015, Mo:0.10-0.40, Ti:≤0.08, Ni:1.30-2.00, Cu:0.30-0.60; the chemical composition of the submerged arc welding agent is: P:≤0.060, S:≤0.030.

[0021] The performance index that can be reached by the welding process of the present application is that the tensile performance of the welded joint and the weld is: tensile strength ReL≥345MPa, yield strength Rm≥490MPa, elongation A≥20%; the impact performance of the welded joint is -20℃KV2≥34J. Wherein ReL is the tensile strength, Rm is the yield strength, A is the elongation, the feasibility of the welding process is determined by these parameters, and the heat input refers to the welding arc heat energy obtained in unit length of the weld.

[0022] Further, in the preferred embodiment of the present application, the welding heat input control range of the flux-cored wire CO2 gas protection semi-automatic welding is: ≤30.8kJ / cm; the welding heat input control range of the submerged arc automatic welding is: ≤59.1kJ / cm.

[0023] Further, in the preferred embodiment of the present application, the pre-welding preheating temperature is determined according to different plate thicknesses, and the determination rule is: When the plate thickness is ≤28mm, the pre-welding preheating temperature is ≥5℃; When the plate thickness is 28-40mm, the pre-welding preheating temperature is 80-120℃.

[0024] The present application carries out the highest hardness test of the welding heat affected zone of the Q345qDNHY-I weathering steel plate with the thickness of 28, 36 and 40 mm respectively according to the conditions stipulated in the "Welding Heat Affected Zone Highest Hardness Test Method" (GB4675.5-84), and the results are 342, 332 and 336 HV10 respectively, close to 350 HV10, indicating that the marine corrosion resistant steel has the tendency of welding cold crack. According to the stipulation of the "Oblique Y-shaped Groove Welding Crack Test Method" (GB4675.1-84), the marine atmospheric corrosion resistant steel Q345qDNHY-I with the thickness of 24 mm, 28 mm, 36 mm and 40 mm is selected as the test material, the CO2 gas protection semi-automatic welding is selected as the welding method, and the welding material with the brand and the diameter of Ф1.2 mm is selected as the welding material. The cracking tendency of the joint surface and section under the welding conditions of ambient temperature, different preheating temperature before welding and strict restraint is studied, and the results show that the surface crack rate and the section crack rate of the welding joint part are zero under the condition that the preheating temperature of the steel plate with the specification of 24 mm is ≥5℃ (without preheating), the preheating temperature of the steel plate with the specifications of 28 mm, 36 mm and 40 mm is 80℃. The test results prove that when the plate thickness is ≤28 mm, the preheating before welding can be not preheated (the room temperature needs to be ensured to be 5℃ and above); when the plate thickness is 28-40 mm, the minimum preheating of 80℃ before welding can avoid the generation of the welding cold crack.

[0025] Further, in the preferred embodiments of the present application, according to different welding joint forms and different welding methods and welding positions, corresponding welding process parameters are determined for welding, including preheating temperature, heat input, interpass temperature, welding current, arc voltage and welding speed, wherein the interpass temperature is not more than 200℃.

[0026] Further, in the preferred embodiments of the present application, for the butt joint of the plate, a V-shaped groove with a root face size of 2 mm and a groove angle of 30° is adopted; the welding process parameters for the backing welding by the flux-cored wire CO2 gas protection semi-automatic welding are as follows: welding current 240-260 A, arc voltage 28-30 V, welding speed 12-20 m / h, heat input 12.1-23.4 kJ / cm; The welding process parameters for the filling and covering welding by the submerged arc welding are as follows: welding current 630-690 A, arc voltage 28-34 V, welding speed 20-26 m / h, heat input 24.4-42.2 kJ / cm. The back welding is subjected to the cleaning treatment before the welding.

[0027] Further, in the preferred embodiment of the present application, for the welding joint of T type partial penetration fillet weld horizontal position, K type groove is adopted, the groove angle is 45°, and the root face size is 2mm; the welding process parameters of the semi-automatic welding of flux-cored wire CO2 gas protection are as follows: welding current 180-200A, arc voltage 26-28V, welding speed 7-9m / h, and heat input 18.8-28.7kJ / cm.

[0028] Further, in the preferred embodiment of the present application, for the welding joint of T type partial penetration fillet weld horizontal position, K type groove is adopted, the groove angle is 45°, and the root face size is 2mm; the welding process parameters of the semi-automatic welding of flux-cored wire CO2 gas protection are as follows: welding current 180-200A, arc voltage 26-28V, welding speed 7-9m / h, and heat input 18.8-28.7kJ / cm.

[0029] Further, in the preferred embodiment of the present application, for the welding joint of T type fillet weld horizontal position, no groove is opened, and the welding process parameters of the automatic welding of submerged arc welding are as follows: welding current 650-750A, arc voltage 30-34V, welding speed 16-24m / h, and heat input 29.3-57.4kJ / cm.

[0030] Further, in the preferred embodiment of the present application, for the welding joint of T type fillet weld horizontal position, no groove is opened, and the welding process parameters of the semi-automatic welding of flux-cored wire CO2 gas protection are as follows: welding current 240-280A, arc voltage 28-32V, welding speed 16-24m / h, and heat input 10.1-20.2kJ / cm. Further, in the preferred embodiment of the present application, for the welding joint of T type fillet weld horizontal position, no groove is opened, and the welding process parameters of the semi-automatic welding of flux-cored wire CO2 gas protection are as follows: welding current 240-280A, arc voltage 28-32V, welding speed 16-24m / h, and heat input 10.1-20.2kJ / cm.

[0031] The welding material used in the present application selects different welding materials according to different welding methods, specifically, the welding material of submerged arc welding adopts a welding wire with a brand of JQ.MH500NH and a diameter of Φ5.0mm, and a welding agent with a brand of JQ.SJ101NH. The welding material of the semi-automatic welding of flux-cored wire CO2 gas protection adopts a flux-cored wire with a brand of JQ.YJ5011NH-1 and a diameter of Φ1.2mm.

[0032] The welding material relates to: the submerged arc welding wire with the model JQ.MH500NH and the diameter of Φ5.0mm, the welding flux with the model JQ.SJ101NH; the flux-cored wire with the model JQ.YJ501NH-1 and the diameter of Φ1.2mm. The welding equipment relates to the ZD5 (D) -1250 type submerged arc welding equipment with the A2 type welding vehicle, the KR500 type gas shielded welding equipment and the direct current reverse polarity.

[0033] Other welding conditions are as follows: 1) the welding flux is dried at 350 DEG C for 2 hours before use; 2) the welding environment temperature is 20-30 DEG C and the environment humidity is 40-60%; 3) the butt joint is cleaned and polished before back welding, which is the common welding condition in the field and can be selected according to actual needs by the person skilled in the art.

[0034] In order to further understand the present application, the present application arranges different plate thicknesses of steel plates to be welded as corresponding different embodiments according to the common welding joint form of bridge structure thick plates, i.e. butt joint and T type corner joint, and the specific welding modes are as follows: The first embodiment is the butt joint with the plate thickness of 28mm+36mm, adopts the method of semi-automatic welding of the flux-cored wire CO2 gas protection for backing welding, filling and surface welding by submerged arc welding, and the back welding is cleaned before back welding, the sizes of the two plates are 28*200*700mm and 36*200*700mm respectively, and the specific joint and groove form schematic diagram and the welding pass arrangement schematic diagram are shown in Figure 1 and Figure 2 respectively. The second embodiment is the T type penetration corner joint welding with the plate thickness of 36mm+28mm, adopts the semi-automatic welding of the flux-cored CO2 gas protection, the back welding is cleaned before back welding, the welding position is horizontal, and the sizes of the test plates are 36*300*500mm and 28*300*500mm respectively, the specific joint and groove form schematic diagram is shown in Figure 3 , and the welding pass arrangement schematic diagram is shown in 4 respectively. The third embodiment is the T type partial penetration corner joint welding with the plate thickness of 18mm+20mm, adopts the semi-automatic welding of the flux-cored CO2 gas protection, the welding position is horizontal, and the sizes of the test plates are 18*300*500mm and 20*300*500mm respectively, the specific joint and groove form schematic diagram is shown in Figure 5 , and the welding pass arrangement schematic diagram is shown in 6 respectively. The fourth embodiment is the T type partial penetration corner joint welding with the plate thickness of 24mm+20mm, adopts the semi-automatic welding of the flux-cored CO2 gas protection, the welding position is vertical, and the sizes of the test plates are 24*300*500mm and 20*300*500mm respectively, the specific joint and groove form schematic diagram is shown in Figure 7The schematic views of the arrangement of the welding beads are shown in Figs. 8, 9 and 10, respectively. The fifth, sixth and seventh embodiments are T-shaped fillet welding of 18mm+20mm plate thickness, and the plate sizes are 18x300x500mm and 20x300x500mm, respectively. The schematic view of the joint is shown in Fig. 11. Figure 9 The schematic views of the arrangement of the welding beads are shown in Figs. 8, 9 and 10, respectively. Figure 10 Figure 11 Figure 12 For the above different plate thicknesses, joint forms and welding methods, the welding is performed according to the welding technical scheme of the present application. The joint form, the groove form, the arrangement and sequence of the welding beads are shown in Figs. 8, 9 and 10, respectively. Figures 1-12 The welding process parameters, including the preheating temperature, the heat input, the interpass temperature, the welding current, the arc voltage and the welding speed, are listed in Table 3, and the results of the method of the present application are shown in Table 4.

[0035] Table 3: Seven groups of different welding modes

[0036] Table 4: Results of the seven groups of different welding modes in Table 3

[0037] The technical effects of the above seven groups of different welding modes of the present application are as follows: ​​​The welding seams of the first to seventh embodiments meet the requirements of article 7.3.1 of the "Code for Design of Highway Steel Structure Bridges" (JTG / T 3651-2022) through visual inspection, and the internal quality of the butt welds and T-type full-length penetration fillet welds meets the requirements of grade 2 of the "Nondestructive Testing of Welds-Ultrasonic Testing- Acceptance Levels" (GB / T 29712-2013) through ultrasonic flaw detection inspection; the internal quality of the T-type partial penetration fillet welds and T-type fillet welds meets the requirements of grade II of the "Code for Design of Railway Steel Bridges" (Q / CR 9211-2015) through ultrasonic flaw detection inspection. In addition, the tensile properties of the joints, the tensile properties of the welds, the Charpy impact energy of the welds and the heat-affected zone (1mm outside the fusion line) at -20℃, the bending properties of the joints, the maximum hardness of the joints, and the weathering alloy index V of the weld metal were tested, and the mechanical properties of the welded joints of the first to seventh embodiments all meet the following technical conditions: tensile strength ReL≥345MPa, yield strength Rm≥490MPa, elongation A≥20%; impact performance of the joint: -20℃KV2≥34J; cold bending performance of the joint: side bending α=180º, intact; maximum hardness of the joint: HV10≤380, which meets the mechanical property requirements of the marine atmospheric corrosion resistant steel in the "Shiziyang Steel Tower Main Tower Steel Shell and Anchor Anchoring System Manufacturing G1 Section Q345qDNHY-I Steel Plate Technical Requirements" of the Shiziyang Channel Project. The weathering alloy index V of the weld is ≥1.29, and the weathering performance is not lower than that of the base material.

[0038] The first to seventh embodiments involve the welding of steel plates of various thickness specifications such as 18mm, 20mm, 24mm, 28mm, and 36mm in different forms, and according to the welding technical scheme and the corresponding test results, the representativeness and applicability can represent the weldability of the marine atmospheric corrosion resistant steel Q345qDNHY-I. Therefore, the welding method of the present application comprehensively covers the joint form and thickness specification of the marine atmospheric corrosion resistant steel Q345qDNHY-I, and the implementation effect meets the technical conditions of the current relevant standards, which can be practically applied to the welding of bridge structures of the marine atmospheric corrosion resistant steel Q345qDNHY-I.

[0039] The present application is directed to the groove form, welding method and welding parameter used by different joint forms and plate thickness of marine atmospheric corrosion resistant steel Q345qDNHY-I, in order to take into account the low temperature impact toughness, weather resistance and welding efficiency of the joint. When the steel plates are butt jointed, the method of adopting CO2 gas protection semi-automatic welding of flux cored wire for backing welding, and adopting submerged arc welding for filling and surface welding is adopted, considering the welding process performance and high efficiency. The backing welding of CO2 gas protection semi-automatic welding of flux cored wire can effectively prevent the leakage that may occur by directly adopting submerged arc welding, and the filling and surface welding adopts submerged arc welding method to improve the deposition efficiency. The butt joint groove form is: the blunt edge size is 2mm, and the groove angle is 30°; the T type penetration angle weld and part of the penetration angle weld open K type groove, the blunt edge size is 2mm, and the groove angle is 45°. By adopting such groove design, the weld filling amount is small, the heat input is small, and the component deformation can be effectively reduced. The T type angle joint is generally continuous weld, and does not require penetration, considering the weather resistance, welding efficiency and weld appearance forming, etc., therefore, the technical scheme of high heat input (29.3-57.4kJ / cm) submerged arc welding and convenient and flexible CO2 gas protection semi-automatic welding of flux cored wire is adopted.

[0040] When the welding material is selected, the present application is directed to the marine atmospheric corrosion resistant steel Q345qDNHY-I, firstly considering the strength, -20℃ charpy impact energy, weather resistance and base material of the weld metal as much as possible, and selecting JQ.MH500NH submerged arc welding wire with JQ.SJ101NH flux, JQ.YJ501NH-1 flux cored wire as the welding material, so that the weld metal contains Cu, Cr, Ni, Mo and other elements to improve the weather resistance of the weld, so as to ensure that the chemical composition of the weld metal is similar to that of the base material, the weather resistance alloy index V is greater than or equal to 1.29, the weather resistance is not lower than that of the base material, and the purity is high, the weld structure is mainly fine acicular ferrite, and the strength and toughness are good, which is a relatively ideal welding material for the marine atmospheric corrosion resistant steel Q345qDNHY-I.

[0041] The technical scheme of the present application is based on the relatively systematic and complete welding process evaluation test and research results, and has relatively sufficient objectivity and rationality. In the implementation process, the present application can achieve the effect of good joint mechanical property, weather resistance and high welding efficiency, and has strong practicability. Therefore, the present application has important role in promoting the development of weather resistant steel bridge in marine climate environment corrosion, and the present application can be applied to the welding of other weather resistant steel, and has strong applicability.

[0042] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only the principles of the present application. Various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A welding process for marine atmospheric corrosion-resistant steel plates, applied to the welding of corrosion-resistant steel plates for marine bridges, characterized in that: For butt joints of plates, a V-groove with a blunt edge of 2mm and a groove angle of 30° is adopted. Flux-cored wire CO2 gas shielded semi-automatic welding is used for root pass welding or submerged arc welding is used for fill and cover pass welding. Root cleaning is performed before welding the reverse side. For the welded joints of T-type full penetration fillet welds and T-type partial full penetration fillet welds, an open K-shaped groove with a blunt edge size of 2mm and a groove angle of 45° is adopted, and a semi-automatic welding method with flux-cored wire and CO2 gas shielding is used. For the welding joints of T-type fillet welds on the ship's position, no beveling is required; submerged arc automatic welding is used. For welded joints of T-type fillet welds welded at the same position, without beveling, a semi-automatic welding method using flux-cored wire and CO2 gas shielding is adopted. The chemical composition of the cladding metal of the flux-cored welding wire is as follows: C:≤0.08, Si:0.10~0.50, Mn:0.50~1.30, P:≤0.025, S:≤0.015, Mo:0.10~0.40, Ti:≤0.08, Ni:1.30~2.00, Cu:0.30~0.60; the chemical composition of the cladding metal of the submerged arc welding wire and the submerged arc welding flux is as follows: C:≤0.08, Si:0.10~0.50, Mn:0.50~1.30, P:≤0.025, S:≤0.015, Mo:0.10~0.40, Ti:≤0.08, Ni:1.30~2.00, Cu:0.30~0.

60.

2. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, Chemical composition of submerged arc welding flux: P:≤0.060, S:≤0.

030.

3. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, The welding heat input control range for CO2 gas shielded semi-automatic welding with flux-cored wire is ≤30.8kJ / cm; the welding heat input control range for submerged arc automatic welding is ≤59.1kJ / cm.

4. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, For different plate thicknesses, the preheating temperature before welding is determined according to the following rules: When the plate thickness is ≤28mm, preheating before welding is ≥5℃; When the plate thickness is 28-40mm, preheat to 80-120℃ before welding.

5. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, The temperature between tracks should not exceed 200℃.

6. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, For butt joints of plates, the welding process parameters for the root pass using flux-cored wire CO2 gas shielded semi-automatic welding are: welding current 240-260A, arc voltage 28-30V, welding speed 12-20m / h, and heat input 12.1-23.4kJ / cm; the welding process parameters for the fill and cover passes using submerged arc welding are: welding current 630-690A, arc voltage 28-34V, welding speed 20-26m / h, and heat input 24.4-42.2kJ / cm.

7. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, For the welded joints of T-type full penetration fillet welds and T-type partial penetration fillet welds, the welding process parameters for semi-automatic welding with flux-cored wire and CO2 gas shielding are as follows: welding current 240~280A, arc voltage 28~32V, welding speed 12~24m / h, and heat input 10.1~26.9kJ / cm.

8. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, For the welded joint of the T-type partial penetration fillet weld in the vertical position, the welding process parameters of the semi-automatic welding with flux-cored wire and CO2 gas shielding are as follows: welding current 180~200A, arc voltage 26~28V, welding speed 7~9m / h, heat input 18.8~28.7kJ / cm.

9. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, For the welding joint of the T-type fillet weld on the ship's position, the welding process parameters for submerged arc welding automatic welding are as follows: welding current 650~750A, arc voltage 30~34V, welding speed 16~24m / h, heat input 29.3~57.4kJ / cm.

10. The welding process for the marine atmospheric corrosion-resistant steel plate according to claim 1, characterized in that, For T-type fillet welds welded in parallel positions, the welding process parameters for semi-automatic welding with flux-cored wire and CO2 gas shielding are as follows: welding current 240~280A, arc voltage 28~32V, welding speed 16~24m / h, heat input 10.1~20.2kJ / cm; For T-shaped fillet welds welded in a vertical position, the welding process parameters for semi-automatic welding with flux-cored wire and CO2 gas shielding are as follows: welding current 160~200A, arc voltage 24~28V, welding speed 7~9m / h, and heat input 15.4~28.8kJ / cm.

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