High-heat-input submerged-arc welding method for liquid ammonia transport ship plate steel
Through the high-thermal input submerged arc welding welding method, the problem of high welding cost for steel for liquid ammonia transport ship plates is solved, and the welding efficiency and cost reduction are improved.
Patent Information
- Application Number
- CN202510476247.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-06-27
AI Technical Summary
The existing welding process has low construction efficiency and high welding wire costs, resulting in the high welding cost of steel for liquid ammonia transport ship plates.
High-heat input submerged arc welding welding method is adopted, including welding bevel processing, pre-weld grinding and selection of matching welding wires to control welding parameters to improve welding efficiency.
On the premise of ensuring welding performance, the cost of welding materials is reduced and the welding efficiency is improved. The welding heat input can reach more than 50KJ/cm, which significantly reduces production and time costs.
Smart Images
Figure CN120205952A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of welding processes, and particularly to a high heat input submerged arc welding method for steel plates used in liquid ammonia transport ships. Background Art
[0002] Ammonia has a stable supply, is convenient for storage and transportation, and does not produce greenhouse gas carbon dioxide when burned, achieving a true "zero" emission. In addition, liquid ammonia also has the advantages of high energy density and easy storage, which can provide stable and reliable energy guarantee for ships and has broad application prospects in the shipping field. Most of the materials for liquid ammonia transport ships in China use steel plates with the grade FH36. FH36 is a widely used ship plate steel with good low-temperature performance.
[0003] During the construction of liquid ammonia transport ships, a large amount of welding work is inevitably required for FH36 steel plates. In the field of shipbuilding, the welding working hours account for about 30% - 40% of the total working hours of hull manufacturing, and the welding cost accounts for 30% - 50% of the hull manufacturing cost. The existing welding process has low construction efficiency and high wire cost, resulting in high construction costs. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high heat input submerged arc welding method for steel plates used in liquid ammonia transport ships.
[0005] To solve the above technical problems, the technical solution of the present invention is as follows: A high heat input submerged arc welding method for steel plates used in liquid ammonia transport ships, comprising: Welding groove machining: machining the welding part of the FH36 steel plate to be welded into a symmetric X-shaped groove; Preparation before welding: grinding both sides of the weld and selecting a wire that matches the FH36 steel plate to be welded; Welding: controlling the interlayer temperature to be less than 150°C, the groove gap to be 3 mm - 4 mm, the root face of the groove to be reserved 2 mm - 2.5 mm, and controlling the welding parameters for the root pass welding to be: welding current 520 ± 20 A, arc voltage 29 ± 2 V, welding speed 60 ± 1 cm / min, and controlling the welding parameters for the fill pass welding to be: welding current 620 ± 20 A, arc voltage 32 ± 2 V, welding speed 24 ± 1 cm / min.
[0006] As a preferred embodiment of the high heat input submerged arc welding method for the steel used in the liquid ammonia carrier ship plate of the present invention, wherein: the chemical components and mass percentages of the welding wire are: C: 0.09%, Si: 0.14%, Mn: 1.41%, P ≤ 0.012%, S ≤ 0.010%, Ni: 2.21%, Cr: 0.03%, Mo: 0.02%, and the balance is Fe and unavoidable impurities.
[0007] As a preferred embodiment of the high heat input submerged arc welding method for the steel used in the liquid ammonia carrier ship plate of the present invention, wherein: the diameter of the welding wire is 4 mm.
[0008] As a preferred embodiment of the high heat input submerged arc welding method for the steel used in the liquid ammonia carrier ship plate of the present invention, wherein: the impact energy of the welding wire at low temperature of -60 °C is greater than or equal to 140 J.
[0009] As a preferred embodiment of the high heat input submerged arc welding method for the steel used in the liquid ammonia carrier ship plate of the present invention, wherein: the chemical components and mass percentages of the FH36 steel plate are C: 0.98%, Mn: 1.55%, Ni: 0.50%, Nb: 0.005%, Ti: 0.005%, Al: 0.015%, Cr: 0.015%, Cu: 0.005%, Si: 0.16%, P: 0.008%, S: 0.004%, and the balance is Fe and other unavoidable impurities.
[0010] As a preferred embodiment of the high heat input submerged arc welding method for the steel used in the liquid ammonia carrier ship plate of the present invention, wherein: the mechanical properties of the FH36 steel plate are tensile strength of 520 MPa, yield strength of 400 MPa, elongation of 30%, and the impact energy Akv at -60 °C is: 188 J, 195 J, 183 J.
[0011] As a preferred embodiment of the high heat input submerged arc welding method for the steel used in the liquid ammonia carrier ship plate of the present invention, wherein: the single-sided groove angle of the X-type groove is 30 ± 1°.
[0012] The beneficial effects of the present invention are: (1) On the premise of ensuring the welding performance, the price of the welding material used in this method is greatly reduced compared with the original welding material for the FH36-level offshore ship plate, reducing the production cost for construction.
[0013] (2) Compared with the traditional submerged arc welding method, the present invention can greatly improve the production efficiency, and the welding heat input can reach more than 50 KJ / cm, reducing the time cost.
[0014] (3) In the backing welding of the present invention, single-sided welding with double-sided formation is adopted, and it is not necessary to use carbon arc air gouging after the backing welding is completed. This avoids carburization of the base metal and the weld seam after air gouging, resulting in the appearance of hardened structures and a decline in corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0016] Figure 1 It is a schematic diagram of the welding groove in the high heat input submerged arc welding method for the steel used in the liquid ammonia carrier plate provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0017] To make the content of the present invention easier to be clearly understood, the present invention will be further described in detail below according to the specific embodiments and in combination with the accompanying drawings.
[0018] The present application provides a high heat input submerged arc welding method for the steel used in the liquid ammonia carrier plate. The method specifically includes the following steps: Step S101: Welding groove processing: Process the welding part of the FH36 steel plate to be welded into a symmetric X-shaped groove.
[0019] Specifically, referring to Figure 1 , the weld seam of the FH36 steel plate to be welded by submerged arc welding adopts a symmetric X-shaped groove, and the single-sided groove angle of the X-shaped groove is 30 ± 1°.
[0020] Step S102: Preparation before welding: Grind both sides of the weld seam and select a welding wire that matches the FH36 steel plate to be welded.
[0021] Specifically, the FH36 steel plate to be welded needs to remove the oil stains and rust on both sides of the weld seam with a grinding machine or other grinding methods, so that both sides of the weld seam are in a pollution-free state before welding.
[0022] The chemical components and mass percentages of the FH36 steel plate to be welded are as follows: C: 0.98%, Mn: 1.55%, Ni: 0.50%, Nb: 0.005%, Ti: 0.005%, Al: 0.015%, Cr: 0.015%, Cu: 0.005%, Si: 0.16%, P: 0.008%, S: 0.004%, and the balance is Fe and other inevitable impurities. Its mechanical properties are as follows: the tensile strength is 520 MPa, the yield strength is 400 MPa, the elongation is 30%, and the impact energy Akv at -60 °C is 188 J, 195 J, and 183 J.
[0023] The strength of the deposited metal of the welding material selected needs to match that of the base metal steel plate. At the same time, since the steel plate contains elements such as Mn, welding materials containing similar alloys need to be selected. Since the service temperature of the steel plate is low, Ni needs to be added to the welding material. According to the above requirements, the chemical components and mass percentages of the selected welding wire are as follows: C: 0.09%, Si: 0.14%, Mn: 1.41%, P ≤ 0.012%, S ≤ 0.010%, Ni: 2.21%, Cr: 0.03%, Mo: 0.02%, and the balance is Fe and inevitable impurities. The impact energy of this welding wire at low temperature of -60 °C is greater than or equal to 140 J, and the low-temperature toughness is excellent. The diameter of the welding wire is 4 mm.
[0024] Step S103: Welding: Control the interlayer temperature to be less than 150 °C, the groove gap is 3 mm to 4 mm, the root face is reserved 2 mm to 2.5 mm, and control the welding parameters of the root pass as follows: welding current 520 ± 20 A, arc voltage 29 ± 2 V, welding speed 60 ± 1 cm / min. Control the welding parameters of the filling pass as follows: welding current 620 ± 20 A, arc voltage 32 ± 2 V, welding speed 24 ± 1 cm / min.
[0025] The above high-heat-input submerged arc welding method will be further described below through specific embodiments.
[0026] Example 1: In this example, the welding groove type is an X-type groove (as shown in the appendix Figure 1 ), and the single-sided groove angle is 30°.
[0027] The submerged arc welding wire used in this example is for high-heat-input welding of FH36 steel plates. The diameter of the submerged arc welding wire is Φ4.0 mm.
[0028] The technical parameters of the welding process in this example are as follows: During root pass welding: the welding current is 500 A; the arc voltage is 26 V; the welding speed is 30 cm / min; during filling pass welding: the welding current is 700 A; the arc voltage is 35 V; the welding speed is 24 cm / min.
[0029] Analysis of the microstructure and mechanical properties of the metal after welding in this embodiment: The microstructure of the weld metal is pearlite + ferrite. After inspection, no solidification cracks or reheat cracks are generated. The mechanical properties after welding are shown in Table 1:
[0030] Table 1 As can be seen from Table 1, by using the high heat input submerged arc welding process for the 50mm FH36 steel plate for liquid ammonia carrier ship plates in this embodiment, after welding, the mechanical properties of the weld and its surrounding areas fully meet the performance requirements for ship plate inspection, and the mechanical properties of the welded joint after welding also meet the performance requirements for the welding of liquid ammonia carrier ship plates.
[0031] Example 2: In this example, the welding groove type is an X-type groove (as shown in the appendix Figure 1 ), and the single-sided groove angle is 30°.
[0032] The submerged arc welding wire used in this embodiment is for high heat input welding of FH36 steel plates. The diameter of the submerged arc welding wire is Φ4.0mm.
[0033] The technical parameters of the welding process in this embodiment are as follows: During backing welding: the welding current is 500A; the arc voltage is 26V; the welding speed is 30cm / min; during filling: the welding current is 740A; the arc voltage is 35V; the welding speed is 24cm / min.
[0034] Analysis of the microstructure and mechanical properties of the metal after welding in this embodiment: The microstructure of the weld metal is pearlite + ferrite. After inspection, no solidification cracks or reheat cracks are generated; the mechanical properties after welding are shown in Table 2:
[0035] Table 2 As can be seen from Table 2, by using the high heat input submerged arc welding process for the 50mm FH36 steel plate for liquid ammonia carrier ship plates in this embodiment, after welding, the mechanical properties of the weld and its surrounding areas fully meet the performance requirements for ship plate inspection, and the mechanical properties of the welded joint after welding also meet the performance requirements for the welding of liquid ammonia carrier ship plates.
[0036] Example 3: In this example, the welding groove type is an X-type groove (as shown in the appendix Figure 1 ), and the single-sided groove angle is 30°.
[0037] The submerged arc welding wire used in this embodiment is for high heat input welding of FH36 steel plates. The diameter of the submerged arc welding wire is Φ4.0mm.
[0038] The technical parameters of the welding process in this embodiment are as follows: During backgouging: the welding current is 500 A; the arc voltage is 26 V; the welding speed is 30 cm / min; during filling: the welding current is 720 A; the arc voltage is 35 V; the welding speed is 24 cm / min.
[0039] Analysis of the microstructure and mechanical properties of the metal after welding in this embodiment: The weld metal structure is pearlite + ferrite structure. After detection, no solidification cracks or reheat cracks are generated; the mechanical properties after welding are shown in Table 3:
[0040] Table 3 As can be seen from Table 3, by using the submerged arc welding process with a large heat input for the 50 mm FH36 steel plate for liquid ammonia carrier ship plates used in this embodiment, after welding, the mechanical properties of the weld and its surrounding area fully meet the performance requirements for ship plate inspection, and the mechanical properties of the welded joint after welding also meet the performance requirements for the welding of liquid ammonia carrier ship plates.
[0041] Therefore, compared with the submerged arc welding of traditional methods, the technical solution of this application uses welding materials with a much lower price, effectively reducing the production cost, and the welding heat input can reach more than 50 KJ / cm, greatly improving the production efficiency and effectively reducing the time cost.
[0042] In addition to the above embodiments, the present invention can also have other implementation manners; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope required by the present invention.
Claims
1. A high heat input submerged arc welding method for steel for liquid ammonia transport ship plates, characterized in that: include: Welding groove processing: Process the welding part of the FH36 steel plate to be welded into a symmetrical X-shaped groove; Preparation before welding: Grind both sides of the weld and select welding wire that matches the FH36 steel plate to be welded; Welding: Control the interlayer temperature to be less than 150℃, the groove gap to be 3mm~4mm, reserve 2mm~2.5mm for the blunt edge of the groove, control the welding parameters of the base welding to be: welding current 520±20A, arc voltage 29±2V, welding speed 60±1cm / min, control the welding parameters of the filling welding to be: welding current 620±20A, arc voltage 32±2V, welding speed 24±1cm / min.
2. The high heat input submerged arc welding method for liquid ammonia transport ship plate steel according to claim 1, characterized in that: The chemical components and mass percentages of the welding wire are: C: 0.09%, Si: 0.14%, Mn: 1.41%, P≤0.012%, S≤0.010%, Ni: 2.21%, Cr: 0.03%, Mo: 0.02%, and the balance is Fe and unavoidable impurities.
3. The high heat input submerged arc welding method for liquid ammonia transport ship plate steel according to claim 1, characterized in that: The diameter of the welding wire is 4 mm.
4. The high heat input submerged arc welding method for liquid ammonia transport ship plate steel according to claim 1, characterized in that: The impact energy of the welding wire at a low temperature of -60°C is greater than or equal to 140J.
5. The high heat input submerged arc welding method for liquid ammonia transport ship plate steel according to claim 1, characterized in that: The chemical composition and mass percentage of the FH36 steel plate are C: 0.98%, Mn: 1.55%, Ni: 0.50%, Nb: 0.005%, Ti: 0.005%, Al: 0.015%, Cr: 0.015%, Cu: 0.005%, Si: 0.16%, P: 0.008%, S: 0.004%, and the balance is Fe and other inevitable impurities.
6. The high heat input submerged arc welding method for liquid ammonia transport ship plate steel according to claim 1, characterized in that: The mechanical properties of the FH36 steel plate are as follows: a tensile strength of 520 MPa, a yield strength of 400 MPa, an elongation of 30%, and an impact energy Akv of 188 J, 195 J, and 183 J at -60°C.
7. The high heat input submerged arc welding method for liquid ammonia transport ship plate steel according to claim 1, characterized in that: The single-side groove angle of the X-shaped groove is 30±1°.