Method for improving welding efficiency of 9% nickel steel butt joint plate weld

Abstract

The application discloses a method for improving welding efficiency of a 9% nickel steel transverse butt joint plate welding seam, and comprises the following steps: (1) X-shaped grooves are formed on the 9% nickel steel plate, and the plate is matched according to the X-shaped groove group size requirements; (2) the bevel of the X-shaped groove of the 9% nickel steel plate is polished, and the impurities on the two sides of the front and back welding seams of the X-shaped groove are removed; (3) a Kama plate is used to strengthen and fix the back welding seam of the 9% nickel steel plate, and an arc extinguishing plate is additionally arranged at the arc extinguishing end of the 9% nickel steel plate welding seam; (4) when the front of the X-shaped groove of the 9% nickel steel plate is welded, bottoming welding is first carried out, then filling welding is carried out, and then surface welding is carried out; (5) when the back of the X-shaped groove of the 9% nickel steel plate is welded, bottoming welding is first carried out, then filling welding is carried out, and then surface welding is carried out; and (6) the appearance of the front and back welding seams and the internal quality of the welding seam are inspected. The welding seam root is well fused, the welding workload is reduced, and the construction cost is lowered.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nickel steel welding, in particular to a method for improving the welding efficiency of 9% nickel steel transverse butt joint panel welds. BACKGROUND

[0002] With the development of LNG natural gas transportation and storage, LNG storage tanks are being used more and more widely, and the main material of LNG storage tanks is 9% nickel steel. Therefore, it is crucial to do a good job in welding 9% nickel steel LNG storage tanks and improve the welding quality and efficiency of 9% nickel steel LNG storage tanks. As far as the current domestic usage is concerned, the butt joint of 9% nickel steel LNG storage tank panels mainly adopts the method of front welding and back welding after carbon stripping.

[0003] However, the method for improving the welding efficiency of 9% nickel steel transverse butt joint panel welds is difficult to operate and requires high panel assembly. Currently, the welding method for 9% nickel steel LNG storage tank panel transverse butt joint welds is front welding and back welding after carbon stripping. Since the back weld is stripped by a carbon rod, the back weld needs to be polished after stripping, which requires the carbon-stripped weld surface to be polished to a bright finish, and then PT non-destructive testing is performed. After no defects are found, the back weld is welded. The carbon stripping and polishing work is heavy, and the welding efficiency is low. Therefore, the current welding method is high in cost in terms of labor hours, energy use and material consumption, which is not conducive to improving the welding quality and efficiency of 9% nickel steel LNG storage tank construction. Therefore, the above problems need to be solved. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method for improving the welding efficiency of 9% nickel steel transverse butt joint panel welds. Compared with the traditional welding method, the weld root fusion is good, the welding workload is reduced, the welding efficiency is improved by more than 1 times, the material cost is reduced by 30%, the labor cost is reduced by 50%, the construction cost is reduced, and the welding quality and efficiency of 9% nickel steel transverse butt joint panel welds are improved.

[0005] To solve the above technical problems, the present application adopts the following technical scheme: the present application provides a method for improving the welding efficiency of 9% nickel steel transverse butt joint panel welds, which has the following steps:

[0006] (1) X-type grooves are made on the 9% nickel steel panels, and the transverse butt joint panels are assembled according to the size requirements of the X-type grooves;

[0007] (2) The beveled edges of the grooves of the 9% nickel steel panels are polished, and the impurities on both sides of the front and back welds of the grooves are removed;

[0008] (3) using the Kama plate to strengthen the 9% nickel steel plate weld back and ensure the assembly gap; then install the same plate thickness and same bevel angle arc extinguishing plate at the arc extinguishing end of the 9% nickel steel plate weld;

[0009] (4) using the welding method from left to right, and when welding the X-type bevel front of the 9% nickel steel plate, first perform the front backing welding; then clean the welding slag on the surface of the backing weld, and then perform the front filling welding using the multi-layer and multi-pass welding arrangement; then grind the oxide layer on the surface of the filling weld, and then perform the front cap welding using the multi-layer and multi-pass annealing welding method;

[0010] In the above steps, the front welding pass number is 4 layers and 8 passes, and the front backing welding uses the ENiGrMo-6 welding rod with a specification of φ3.2, the welding current is 110-140 A, the welding voltage is 21-24 V, and the welding speed is 140-190 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; the first backing layer uses the continuous arc breaking operation method combined with the up and down sawtooth welding swing gesture, the welding rod continuous arc breaking should be at the gap hole position of the weld, and then a hole is formed at the front end of the weld pool during welding; the back weld height is controlled within 1-2 mm, and the weld width is controlled within 4-6 mm; the shrinkage hole generated at the crater position is ground out to form a transition slope at the backing weld joint, and the welding rod is quickly pulled to the joint position after the arc is started from the upper end of the weld joint;

[0011] In the above steps, the front filling welding uses the ENiGrMo-6 welding rod with a specification of φ4.0, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, and the left and right angle of the welding rod is 60-80°; the straight line pause small swing continuous arc welding swing gesture is used during the filling welding, and the up and down channel welding is started from the second layer, and the welding rod is walked along the backing weld line during welding; the single pass weld width is not greater than 3.5 times the diameter of the welding rod, and the single pass weld thickness is controlled within 4 mm;

[0012] (5) when welding the X-type bevel back of the 9% nickel steel plate, first perform the back backing welding; then clean the welding slag on the surface of the backing weld, and then perform the back filling welding using the multi-layer and multi-pass welding arrangement; then grind the oxide layer on the surface of the filling weld, and then perform the back cap welding using the multi-layer and multi-pass annealing welding method;

[0013] In the above step, the back side of the bottom filling cover welding is welded by 4 layers and 7 passes, and the back side of the bottom welding uses the welding rod with the ENiGrMo-6 brand and the φ3.2 specification, the welding current is 110-140 A, the welding voltage is 21-24 V, and the welding speed is 140-190 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; the bottom welding is welded by two passes, the welding gesture is the linear pause gesture, and the welding rod is walked along the lower edge line and the upper edge line of the back side of the bottom welding seam;

[0014] In the above step, the back side of the bottom filling welding uses the welding rod with the ENiGrMo-6 brand and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°; the filling welding uses the linear pause small swing continuous arc welding gesture, all the welding is selected by the up and down passes, the welding rod is walked along the bottom welding seam edge line during the welding; the single pass welding seam width is not more than 3.5 times of the welding rod diameter, and the thickness of the single pass welding seam is controlled within 4 mm;

[0015] (6) The appearance of the welding seam and the internal quality of the welding seam are inspected.

[0016] Preferably, in the above step (1), the 9% nickel steel plate uses the 9% nickel steel with the EN10028-4 brand and the 30 mm thickness; the joint form of the 9% nickel steel plate is X-shaped, and the two side bevel angles of the 9% nickel steel plate are 50-60°, the bevel face blunt edge is 1-2 mm, and the root gap is 2-6 mm.

[0017] Preferably, in the above step (2), the impurity removal range is within 30 mm of the welding seam on the two sides of the 9% nickel steel plate.

[0018] Preferably, in the above step (4), the front side of the cover welding uses the welding rod with the ENiGrMo-6 brand and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; the cover welding uses the linear pause welding gesture, and the welding seam of the cover welding needs to be controlled to cover the position of the previous welding seam and the bevel edge line during the welding of each welding seam, and the interlayer temperature of the welding seam is controlled to be 100-150 ℃ during the front side welding.

[0019] Preferably, in the step (5), the back cover surface welding selects the welding rod with the ENiGrMo-6 mark and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; the linear pause welding swing gesture is adopted during the cover surface welding, the molten pool edge line needs to be controlled to cover the position of the previous weld and the groove edge line during the welding of each weld of the cover surface welding, and the interlayer temperature of the weld is controlled at 100-150 DEG C during the back welding process.

[0020] The beneficial effects of the present application are:

[0021] (1) Compared with the traditional welding method, the present application has good weld root fusion, reduces the welding workload, improves the welding efficiency by more than 1 times, reduces the material cost by 30%, reduces the labor cost by 50%, and further reduces the construction cost, improves the welding quality and welding efficiency of the 9% nickel steel butt joint plate weld by 9%;

[0022] (2) The present application does not need to carbon planing and grinding of the back, thereby greatly improving the welding efficiency of the 9% nickel steel butt joint plate weld;

[0023] (3) The present application effectively controls the welding heat input of the welding process, ensures the fusion ratio of the weld, strictly controls the interlayer temperature of the weld, and forms good front and back welds, and has good mechanical properties such as tensile and bending, and meets the low temperature impact requirement of-196 DEG C;

[0024] (4) The welding method without carbon planing and grinding of the present application can effectively prevent the problem of carbon penetration in the weld produced by carbon planing, thereby improving the internal quality of the 9% nickel steel butt joint plate weld. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0026] Figure 1 It is a schematic diagram of the butt joint plate of the present application.

[0027] Figure 2 It is a schematic diagram of the assembly of the cam plate of the present application.

[0028] Figure 3 It is a schematic diagram of the assembly of the arc extinguishing plate of the present application.

[0029] Figure 4 The welding pass arrangement of the welding seam of the present application.

[0030] Wherein, 1-9% nickel steel plate; 2- Kama plate; 3- arc extinguishing plate. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be clearly and completely described below through specific embodiments.

[0032] A method for improving the welding efficiency of 9% nickel steel transverse butt plate welding seam of the present application, as shown in the figure, comprises the following steps: Figures 1-4

[0033] (1) Open X-type groove on the 9% nickel steel plate 1, and complete the transverse butt type assembly according to the size requirements of the X-type groove assembly;

[0034] In the above steps, the 9% nickel steel plate 1 is selected from 9% nickel steel with a grade of EN10028-4 and a thickness of 30mm; the material has very good mechanical properties, especially at extremely low temperatures, such as impact performance greater than 41J at-196℃, but the material has higher requirements for welding line energy control during welding, and the welding process is more complex, and the interpass temperature should be strictly controlled during welding.

[0035] The joint form of the 9% nickel steel plate 1 in the present application is X-shaped, and the groove angle of the two sides thereof is 50-60°, the groove face bevel is 1-2mm, and the root gap is 2-6mm.

[0036] (2) Grind the groove face bevel of the 9% nickel steel plate 1, and remove the primer, rust and other impurities on both sides of the groove front and back welds thereof;

[0037] In the above steps, the impurity removal range is within 30mm on both sides of the groove front and back welds of the 9% nickel steel plate 1.

[0038] (3) Adopt the Kama plate 2 to strengthen and fix the welding back of the 9% nickel steel plate 1, and ensure the assembly gap; then install the arc extinguishing plate 3 with the same plate thickness and groove angle at the arc extinguishing end of the 9% nickel steel plate 1 welding seam, so as to ensure the welding quality of the starting and ending arc weld of the 9% nickel steel plate 1 welding seam.

[0039] (4) Adopt the welding method from left to right welding direction, and when welding the X-type groove front of the 9% nickel steel plate 1, first perform front backing welding; then clean the welding slag on the surface of the backing welding seam, and then adopt the multi-layer and multi-pass welding pass arrangement to perform front filling welding; then grind the oxidation layer on the surface of the filling welding seam, and then adopt the multi-layer and multi-pass annealing welding method to perform front surface welding;

[0040] ​In the above steps, the number of front welding passes is 4 layers and 8 passes, and the front welding is selected by using the welding rod with the ENiGrMo-6 brand and the φ3.2 specification, the welding current is 110-140 A, the welding voltage is 21-24 V, and the welding speed is 140-190 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; the first pass of the backing layer is welded by using the continuous interrupted arc operation method and combining the up and down sawtooth welding swing gesture, the continuous interrupted arc of the welding rod is located at the gap hole position of the welding seam, and then the hole is formed at the front end of the welding pool during welding, so that the back of the welding seam can achieve the effect of single-sided welding and double-sided forming; the height of the back welding seam is controlled within 1-2 mm, and the width of the welding seam is controlled within 4-6 mm; the shrinkage hole generated at the crater position is ground to a transition slope at the joint of the backing welding seam, the welding rod is quickly pulled to the joint position after the arc is started from the upper end of the welding seam joint, and then the welding seam formation and joint quality of the backing welding seam are ensured.

[0041] In the above steps, the front filling welding is selected by using the welding rod with the ENiGrMo-6 brand and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, and the left and right angle of the welding rod is 60-80°; the straight line pause small swing continuous arc welding swing gesture is used for the filling welding, as shown in Figure 4 The up and down channel welding is started from the second layer, the welding rod is walked along the backing welding seam line during welding, and the penetration of the welding fusion line is ensured; at the same time, the welding speed should be controlled, the single-pass welding seam width is not greater than 3.5 times the diameter of the welding rod, and the thickness of the single-pass welding seam is controlled within 4 mm, so as to ensure the penetration of the welding seam, improve the welding speed, and reduce the welding line energy.

[0042] In the above steps, the front covering welding is selected by using the welding rod with the ENiGrMo-6 brand and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; as shown in Figure 4 The straight line pause welding swing gesture is used for the covering welding, and the molten pool line of the covering welding needs to be controlled to cover the position of the previous welding seam and the groove line during the welding of each pass of the covering welding, so as to ensure the welding seam overlapping forming and the flatness of the welding seam, and the interlayer temperature of the welding seam is controlled within 100-150℃ during the front welding process.

[0043] The welding rod used in the present application has a linear expansion coefficient close to 9% nickel steel, and does not need preheating before welding, has high low-temperature toughness and good crack resistance; in addition, the welding material needs to be placed in a constant-temperature room, and the welding material should not be placed in a damp place to avoid welding defects during welding.

[0044] (5) When welding the X-shaped groove back of the 9% nickel steel plate 1, first, back welding is performed; then, the slag on the surface of the back welding is cleaned, and then, the back filling welding is performed by using a multi-layer and multi-pass welding arrangement; then, the oxide layer on the surface of the filling welding is polished, and then, the back cap welding is performed by using a multi-layer and multi-pass annealing welding method;

[0045] In the above steps, after the front welding is completed, the back does not need to be cleaned by carbon planing, and directly performs the backing welding; the back welding is welded by 4 layers and 7 passes, and the back welding uses the welding rod with the ENiGrMo-6 mark and the φ3.2 specification, the welding current is 110-140 A, the welding voltage is 21-24 V, and the welding speed is 140-190 mm / min; the up-down angle of the welding rod is 80-90°, the left-right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled to be within 2 mm; as shown in the drawing, the back welding uses two upper and lower passes, the welding swing is a linear pause welding gesture, and the welding rod walks along the lower edge line and the upper edge line of the back welding seam to ensure the penetration of the two sides of the back welding seam and the flatness of the welding seam. Figure 4

[0046] In the above steps, the back filling welding uses the welding rod with the ENiGrMo-6 mark and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up-down angle of the welding rod is 80-90°, and the left-right angle of the welding rod is 60-80°; the filling welding uses a linear pause small swing continuous arc welding swing gesture, as shown in the drawing, all upper and lower passes are selected, the welding rod walks along the back welding seam edge line to ensure the penetration of the welding seam fusion line; and attention should be paid to control the welding speed, the single-pass welding seam width is not greater than 3.5 times the diameter of the welding rod, and the thickness of the single-pass welding seam is controlled to be within 4 mm, so as to ensure the penetration of the welding seam and improve the welding speed and reduce the welding line energy. Figure 4

[0047] In the above steps, the back cap welding uses the welding rod with the ENiGrMo-6 mark and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up-down angle of the welding rod is 80-90°, the left-right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled to be within 2 mm; as shown in the drawing, the back cap welding uses two upper and lower passes, the welding swing is a linear pause welding gesture, and the welding rod walks along the back welding seam edge line to ensure the penetration of the two sides of the back welding seam and the flatness of the welding seam. Figure 4 ​​As shown, the cover face welding adopts a linear pause welding swing gesture, and the molten pool edge line of each cover face welding seam needs to be controlled to cover the position of the previous welding seam and the groove edge line to ensure the weld overlay forming and the flatness of the weld, and the interlayer temperature of the weld is controlled at 100-150 DEG C during the reverse welding process.

[0048] (6) The appearance of the front and back of the weld and the internal quality of the weld are inspected.

[0049] Through the welding of the present application, the visual appearance of the front and back of the weld is good, and there are no defects such as undercut, porosity, incomplete fusion, and cracks, and the internal quality of the weld is also good and has no defects through the RT nondestructive testing. In addition, according to the ASME specification volume V standard, the 9% nickel steel transverse butt joint plate weld is sampled for tensile, impact, bending, macroscopic, microscopic, fatigue test, and other mechanical property tests, and the test results show that they all meet the welding process requirements of 9% nickel steel.

[0050] The beneficial effects of the present application are:

[0051] (1) Compared with the conventional welding method, the root fusion of the weld is good, the welding workload is reduced, the welding efficiency is improved by more than 1 times, the material cost is reduced by 30%, the labor cost is reduced by 50%, and the construction cost is reduced, and the welding quality and efficiency of the 9% nickel steel transverse butt joint plate weld are improved;

[0052] (2) The present application does not need to carbon mill to remove the root and polish, thereby greatly improving the welding efficiency of the 9% nickel steel transverse butt joint plate weld;

[0053] (3) The present application effectively controls the welding heat input of the welding process, ensures the fusion ratio of the weld, strictly controls the interlayer temperature of the weld, and forms the front and back of the weld well, and the mechanical properties such as tensile and bending are good, and meet the low temperature impact requirements of-196 DEG C;

[0054] (4) The welding method without carbon mill to remove the root of the present application can effectively prevent the problem of carbon mill to the weld, thereby improving the internal quality of the 9% nickel steel transverse butt joint plate weld.

[0055] The above-described embodiments are merely preferred embodiments of the present application, and do not limit the concept and scope of the present application. Various modifications and improvements to the technical solutions of the present application made by ordinary engineering technicians in the art without departing from the design concept of the present application shall fall within the protection scope of the present application. The technical content claimed by the present application has been fully recorded in the technical requirements.

Claims

1. A method for improving the welding efficiency of a 9% nickel steel butt strap weld, the method comprising: The method comprises the following steps: ​ (1) X-shaped bevels are opened on 9% nickel steel plates, and the plates are assembled according to the size requirements of the X-shaped bevels; (2) the chamfer of the 9% nickel steel plates is polished, and the impurities on both sides of the chamfer are removed; (3) a Kammprofile plate is used to fix the back of the 9% nickel steel plate weld, and the assembly gap is ensured; an arc extinguishing plate with the same thickness and bevel angle as the plate is installed at the arc extinguishing end of the 9% nickel steel plate weld; (4) the welding method from left to right is adopted, and when the X-shaped bevel of the 9% nickel steel plate is welded, the front bottoming welding is first performed; then the welding slag on the surface of the bottoming welding is cleaned, the front filling welding is performed by adopting a multi-layer and multi-pass welding arrangement, the oxidation layer on the surface of the filling welding is polished, and the front surface welding is performed by adopting a multi-layer and multi-pass annealing welding method; In the above steps, the number of front welding passes is 4 layers and 8 passes, the front bottoming welding uses a welding rod with a specification of ENiGrMo-6 and a size of φ3.2, the welding current is 110-140 A, the welding voltage is 21-24 V, and the welding speed is 140-190 mm / min; the up-down angle of the welding rod is 80-90°, the left-right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled to be less than 2 mm; the first bottoming layer is welded by adopting a continuous arc breaking operation method combined with up-down sawtooth welding swing gestures, the welding rod continuously breaks the arc at the gap hole position of the weld, and a hole is formed at the front end of the weld pool during welding; the back weld height is controlled to be 1-2 mm, and the weld width is controlled to be 4-6 mm; the shrinkage hole generated at the crater position is polished to form a transition slope, and the welding rod is quickly pulled to the joint position after the arc is started from the upper end of the weld joint; In the above steps, the front filling welding uses a welding rod with a specification of ENiGrMo-6 and a size of φ4.0, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up-down angle of the welding rod is 80-90°, and the left-right angle of the welding rod is 60-80°; the straight-line pause small swing continuous arc welding swing gesture is adopted during the filling welding, and the up-down split welding is started from the second layer, and the welding rod is walked along the bottoming weld line during welding; the single-pass weld width is not greater than 3.5 times the diameter of the welding rod, and the single-pass weld thickness is controlled to be less than 4 mm; (5) when the X-shaped bevel of the 9% nickel steel plate is welded, the back bottoming welding is first performed; then the welding slag on the surface of the bottoming welding is cleaned, the back filling welding is performed by adopting a multi-layer and multi-pass welding arrangement, the oxidation layer on the surface of the filling welding is polished, and the back surface welding is performed by adopting a multi-layer and multi-pass annealing welding method; In the above step, the back side of the bottom filler cover welding is welded by 4 layers and 7 passes, and the back side of the bottom welding uses the welding rod with the ENiGrMo-6 brand and the φ3.2 specification, the welding current is 110-140 A, the welding voltage is 21-24 V, and the welding speed is 140-190 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; the bottom welding is welded by two passes, the welding gesture is the linear pause gesture, and the welding rod is walked along the lower edge line and the upper edge line of the back side of the bottom welding seam; In the above step, the back side of the bottom welding uses the welding rod with the ENiGrMo-6 brand and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°; the welding gesture is the linear pause small swing continuous arc gesture, all the welding is selected by the up and down passes, and the welding rod is walked along the edge line of the bottom welding seam; the single pass welding seam width is not more than 3.5 times of the welding rod diameter, and the thickness of the single pass welding seam is controlled within 4 mm; (6) The appearance of the welding seam and the internal quality of the welding seam are inspected.

2. The method for improving the welding efficiency of the butt joint welding seam of 9% nickel steel according to claim 1, characterized in that: In the above step (1), the 9% nickel steel plate uses the 9% nickel steel with the EN10028-4 brand and the 30 mm thickness; the joint form of the 9% nickel steel plate is X-shaped, and the two side bevel angles are 50-60°, the bevel face blunt edge is 1-2 mm, and the root gap is 2-6 mm.

3. The method for improving the welding efficiency of the butt joint welding seam of 9% nickel steel according to claim 1, characterized in that: In the above step (2), the impurity removal range is within 30 mm of the welding seam on the bevel of the 9% nickel steel plate.

4. The method for improving the welding efficiency of the butt joint welding seam of 9% nickel steel according to claim 1, characterized in that: In the above step (4), the front side of the cover welding uses the welding rod with the ENiGrMo-6 brand and the φ4.0 specification, the welding current is 140-170 A, the welding voltage is 24-27 V, and the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; the welding gesture is the linear pause gesture, the welding seam of each pass of the cover welding needs to be controlled to cover the position of the previous welding seam and the bevel edge line, and the interlayer temperature of the welding seam is controlled to be 100-150℃ during the front side welding.

5. The method for improving the welding efficiency of the butt joint welding seam of 9% nickel steel according to claim 1, characterized in that: In the step (5), the back cover surface welding selects the welding rod with the brand of ENiGrMo-6 and the specification of φ4.0, the welding current is 140-170 A, the welding voltage is 24-27 V, the welding speed is 180-260 mm / min; the up and down angle of the welding rod is 80-90°, the left and right angle of the welding rod is 60-80°, and the arc length of the welding rod is controlled within 2 mm; the linear pause welding swing gesture is adopted during the cover surface welding, and the molten pool edge line needs to be controlled to cover the position of the previous weld and the groove edge line during the welding of each weld of the cover surface welding, and the interlayer temperature of the weld is controlled at 100-150 ℃ during the back welding process.

Images