1000mpa grade low temperature high toughness gas shielded welding wire for ocean engineering
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA IRON & STEEL RESEARCH INSTITUTE GROUP CO LTD
- Filing Date
- 2024-08-07
- Publication Date
- 2026-07-07
AI Technical Summary
[0004]鉴于上述的分析，本发明旨在提供一种1000MPa级海洋工程用低温高韧性气保焊丝，用以解决现有焊丝强韧性匹配不合理，强度高韧性差，韧性高强度不足、冷裂纹敏感性较高等问题中的至少一个
[0017](1)本发明选用特定的焊丝成分及比例，焊丝合金体系为Si-Mn-Ni-Cr-Mo体系，焊缝金属中Ni元素含量较高，合金元素总含量不超过7.72％，相比同级别焊丝整体合金元素含量较低，使得焊丝制造成本降低，淬硬倾向下降，易于实现低温无裂纹焊接，提高焊接接头安全性。此外，由本发明的焊丝所制得熔敷金属组织主要由交织的板条马氏体和板条贝氏体构成，交织组织有利于阻碍裂纹扩展，提高熔敷金属性能，制备熔敷金属具有较高的强度，同时低温韧性良好，适用于1000MPa级海洋工程用高强钢焊接。本发明通过成分级配比设计，获得一种抗拉强度和屈服强度均达到1000MPa级以上，-50℃冲击功≥60J，延伸率≥15％的焊丝。
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of welding wires, and particularly to a 1000MPa grade low-temperature and high-toughness gas shielded welding wire for offshore engineering. Background Art
[0002] Offshore engineering equipment is the prerequisite and foundation for the exploration and development of marine resources. Offshore engineering equipment mainly includes offshore drilling platforms, submarine oil and gas pipelines, submarine energy equipment, and ships and vessels, etc. Offshore engineering equipment is a landmark equipment for marine resource development. In the use of offshore engineering equipment, the proportion of high-strength steel is as high as 60% - 90%. As a super-large welded steel structure, welding accounts for 50 - 70% of the total working hours. Therefore, the reliability of high-strength steel welding is a key factor to ensure the safety of marine equipment.
[0003] At present, the strength levels of the steel used in offshore engineering in China are mostly in the range of 300 - 800MPa. For higher-strength steel of 1000MPa grade and above for offshore engineering, research and development are underway. Enterprises such as Baosteel have made certain progress. Most of the welding materials supporting 1000MPa grade offshore engineering steel rely on imports. Domestic high-strength steel welding wire manufacturers mainly include Jinqiao, Daqiao, Atlantic, and Steel Research Institute, etc. Among them, some manufacturers have mass-produced 90kg and 100kg grade gas shielded welding wires with the Mn-Ni-Mo alloy system, but the strength still does not reach the 1000MPa level, and the low-temperature toughness is relatively poor. Summary of the Invention
[0004] In view of the above analysis, the present invention aims to provide a 1000MPa grade low-temperature and high-toughness gas shielded welding wire for offshore engineering to solve at least one of the problems such as unreasonable matching of strength and toughness of existing welding wires, poor toughness at high strength, insufficient strength at high toughness, and relatively high cold crack sensitivity.
[0005] In a first aspect, the present invention provides a 1000MPa grade low-temperature and high-toughness gas shielded welding wire for offshore engineering. According to mass percentage, the welding wire comprises the following components:
[0006] C 0.05 - 0.12%, Si 0.3 - 0.6%, Mn 1.0 - 2.0%, Ni 1.5 - 3.0%, Cr 0.4 - 1.0%, Mo 0.75 - 1.0%, S ≤ 0.005%, P ≤ 0.005%, and the balance is Fe and inevitable impurities.
[0007] Further, the diameter of the welding wire is 1.15 - 1.2mm.
[0008] Further, the tensile strength of the welding wire ≥ 1000MPa, the yield strength ≥ 1000MPa, the impact energy at -50°C ≥ 60J, and the elongation ≥ 15%.
[0009] Secondly, the present invention provides a method for preparing the welding wire, comprising: vacuum smelting of raw materials, bright drawing, and cleaning to obtain the welding wire.
[0010] Thirdly, the present invention provides a welding method for the aforementioned welding wire, comprising welding under 95% Ar + 5% CO2 protection.
[0011] Furthermore, the welding current is 250–270A, and the welding voltage is 25–27V.
[0012] Furthermore, the welding speed is 320–350 mm / min.
[0013] Furthermore, the preheating temperature during welding is 80–120°C, and the preheating time is 1–2 hours.
[0014] Furthermore, the post-weld heating temperature is 200–250°C, and the time is 1.5–2 hours.
[0015] Fourthly, the present invention provides an application of the welding wire described above in welding 1000MPa grade marine engineering steel.
[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:
[0017] (1) This invention selects specific welding wire components and proportions. The welding wire alloy system is a Si-Mn-Ni-Cr-Mo system, with a high Ni content in the weld metal and a total alloy element content not exceeding 7.72%. Compared with welding wires of the same grade, the overall alloy element content is lower, which reduces the manufacturing cost of the welding wire, decreases the hardening tendency, facilitates low-temperature crack-free welding, and improves the safety of the welded joint. In addition, the microstructure of the weld metal obtained by the welding wire of this invention is mainly composed of interwoven lath martensite and lath bainite. The interwoven structure helps to hinder crack propagation, improves the performance of the weld metal, and produces weld metal with high strength and good low-temperature toughness, suitable for welding high-strength steel for marine engineering of 1000MPa grade. This invention obtains a welding wire with tensile strength and yield strength of 1000MPa or higher, impact energy at -50℃ ≥60J, and elongation ≥15% through component gradation design.
[0018] (2) The welding method of the present invention adopts gas shielded welding. Compared with other methods (manual arc welding, tungsten inert gas welding, etc.), it solves the problems of poor strength and toughness matching of 1000MPa grade high-strength steel welding materials and high sensitivity to cold cracking while ensuring production efficiency and welding quality.
[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description
[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.
[0021] Figure 1 The microstructure of the weld metal made from the welding wire of Embodiment 1 of the present invention;
[0022] Figure 2 The microstructure of the weld metal made from the welding wire of Embodiment 2 of the present invention. Detailed Implementation
[0023] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.
[0024] A specific embodiment of the present invention discloses a 1000MPa grade low-temperature high-toughness gas-shielded welding wire for marine engineering. The welding wire comprises the following components by weight percentage:
[0025] C 0.05-0.12%, Si 0.3-0.6%, Mn 1.0-2.0%, Ni 1.5-3.0%, Cr 0.4-1.0%, Mo 0.75-1.0%, S≤0.005%, P≤0.005%, with the balance being Fe and unavoidable impurities.
[0026] This invention selects specific welding wire compositions and proportions. The welding wire alloy system is a Si-Mn-Ni-Cr-Mo system, with Ni being the most abundant element in the weld metal. The total alloy element content does not exceed 7.72%, which is lower than that of welding wires of the same grade. This reduces the manufacturing cost of the welding wire, decreases the hardening tendency, facilitates low-temperature crack-free welding, and improves the safety of the welded joint. Furthermore, the microstructure of the weld metal obtained from the welding wire of this invention mainly consists of interwoven lath martensite and lath bainite. This interwoven structure helps to inhibit crack propagation, improves the performance of the weld metal, and produces a weld metal with high strength and good low-temperature toughness, suitable for welding high-strength steel for marine engineering applications up to 1000MPa.
[0027] This invention, through component design, obtains a welding wire with tensile strength and yield strength both reaching 1000MPa or higher, impact energy at -50℃ ≥60J, and elongation ≥15%.
[0028] The design principle of the composition and proportion of the welding wire described in this invention is as follows:
[0029] C: C is a strengthening element that can improve the hardenability of weld metal, increase the tendency of martensitic transformation and the sensitivity to cold cracking in welding, and thus worsen the low-temperature impact toughness. Therefore, under the premise of meeting the strength requirements, the C content should be reduced as much as possible. In this invention, the C content is selected as 0.05%-0.12%.
[0030] Si: Si has the function of deoxidation and strengthening of the weld matrix. However, excessive Si content will increase the hardenability of the weld metal, resulting in a decrease in the ductility and toughness of the weld metal. In this invention, the Si content is selected as 0.3-0.6%.
[0031] Mn: Like Si, Mn has the function of deoxidation and strengthening the weld matrix, and it is also beneficial to weld desulfurization and prevents the formation of iron sulfides that cause hot cracking. However, excessive Mn content will significantly reduce the low-temperature impact toughness of weld metal. In this invention, the Mn content is selected as 1.0-2.0%.
[0032] Ni: Ni is an austenite-forming element that can exist in austenite and ferrite structures in a mutually soluble form with Fe, playing a role in solid solution strengthening and improving strength. It also improves low-temperature impact toughness and lowers the ductile-brittle transition temperature. Therefore, Ni is an ideal alloying element for welding materials of 1000MPa grade high-strength steel. Thus, the Ni content in this invention is 1.5-3.0%.
[0033] Cr: Cr is a ferrite-forming element and a medium-strong carbide-forming element. Its carbides increase the strength and hardness of the weld metal, and Cr can improve the hardenability of the weld structure, increasing the amount of martensite and bainite, but decreasing the plasticity and toughness. Therefore, the Cr content in this invention is selected as 0.4-1.0%.
[0034] Mo: Mo is the main element for obtaining high-strength weld metal; as a high-melting-point substance, it has a good grain-refining effect and improves strength with minimal damage to ductility and toughness. It can significantly improve the hardenability of steel and prevent temper brittleness. Therefore, the Mo content in this invention is 0.75-1.0%.
[0035] S and P: S and P are harmful elements, and their content must be controlled to improve weld purity and weldability. S and P are highly prone to segregation; they easily form non-metallic inclusions and second-phase particles between grains. They can significantly reduce the plasticity and toughness of steel. The content of S and P in welding wire must be strictly controlled. Therefore, in this invention, S is controlled to be ≤0.005% and P to be ≤0.005%.
[0036] In one specific embodiment, the diameter of the welding wire is 1.15 to 1.2 mm.
[0037] Another specific embodiment of the present invention discloses a method for preparing the above-mentioned welding wire, comprising: vacuum smelting of raw materials, bright drawing, and cleaning to obtain the welding wire.
[0038] Preferably, the specific methods include the following: using desulfurized molten iron, controlling the content of impurity elements in the molten iron entering the furnace, selecting vacuum induction furnace smelting method with a vacuum degree of less than 1 Pa, controlling the elements in the smelting process within the design range, and further specifying that the impurity elements are S≤0.005wt%, P≤0.005wt%, O≤0.003wt%, N≤0.003wt%, and H≤0.0003wt%. The raw materials are refined three times at a refining temperature of 1580±20℃, with refining times of 30~50min, 20~40min, and 20~30min respectively. After refining, the molten steel is cast into a continuous casting billet, which is then rolled into a 5.5mm diameter wire rod by a rolling mill. After mechanical peeling, the wire rod is ground with a sand belt and then drawn into a roller die. After four drawing processes, a 1.2mm finished welding wire is obtained. The welding wire is then surface-cleaned and dried, and then wound to form the finished welding wire.
[0039] It should be noted that vacuum smelting can prevent metal oxidation, effectively remove impurities from steel, and ensure the purity of the smelted steel, thereby achieving the goal of low impurity content in the welding wire. Welding wire prepared by bright drawing has a bright surface, fewer scratches and wear, is easier to feed, improves welding efficiency, and allows for cleaning and wiping of oil, water, etc., reducing the intrusion of hydrogen during welding.
[0040] The above method effectively controls the content of impurity elements such as P and S in the welding wire, resulting in a lower content of impurity elements such as hydrogen, which greatly improves the crack resistance, ensures the use and service performance of the welding wire in low-temperature environments, and significantly extends the service life of the welded joint.
[0041] In one specific embodiment, the welding wire has a tensile strength ≥1000MPa, a yield strength ≥1000MPa, an impact energy at -50℃ ≥60J, and an elongation ≥15%.
[0042] Preferably, the welding wire has a tensile strength of 1076-1110 MPa, a yield strength of 1007-1025 MPa, an impact energy of 60-84 J at -50℃, and an elongation of 16.0-18.5%.
[0043] Another specific embodiment of the present invention discloses a welding method using the above-described welding wire, comprising welding under 95% Ar + 5% CO2 protection. Wherein, Ar and CO2 are volume percentages.
[0044] In one specific implementation, the welding current is 250–270A, for example, 250A, 255A, 260A, 265A, or 270A, and the welding voltage is 25–27V, for example, 25V, 26V, or 27V.
[0045] In one specific embodiment, the welding speed is 320 to 350 mm / min, for example, 320 mm / min, 325 mm / min, 330 mm / min, 335 mm / min, 340 mm / min, 345 mm / min, or 350 mm / min.
[0046] In one specific embodiment, the preheating temperature during welding is 80–120°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, or 120°C, and the preheating time is 1–2 hours, for example, 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, or 2 hours.
[0047] In one specific embodiment, the post-weld heat temperature is 200–250°C, for example, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, or 250°C, and the time is 1.5–2 hours, for example, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, or 2 hours.
[0048] It should be noted that the welding method of the present invention adopts gas shielded welding. Compared with other methods (manual arc welding, tungsten inert gas welding, etc.), it solves the problems of poor strength and toughness matching of 1000MPa grade high-strength steel welding materials and high sensitivity to cold cracking while ensuring production efficiency and welding quality.
[0049] Another specific embodiment of the present invention discloses the application of the above-mentioned welding wire in welding 1000MPa grade marine engineering steel.
[0050] The technical solution of the present invention will be further explained below with reference to specific embodiments.
[0051] Example 1
[0052] The components and contents of the welding wire in this embodiment are shown in Table 1. The preparation method of the welding wire in this embodiment is as follows: desulfurized molten iron is used, and the content of impurity elements in the molten iron entering the furnace is controlled. Vacuum induction furnace smelting is selected, with a vacuum degree of less than 1 Pa. The elements in the smelting process are controlled within the design range. In addition, the impurity elements are S≤0.005wt%, P≤0.005wt%, O≤0.003wt%, N≤0.003wt%, and H≤0.0003wt%. The raw materials are refined three times at a temperature of 1580±20℃ for three refining times of 30-50 min, 20-40 min, and 20-30 min, respectively. After refining, the molten steel is cast into a continuous casting billet, which is then rolled into a wire rod with a diameter of 5.5 mm by a rolling mill. After mechanical peeling, the wire rod is ground by a sand belt and then drawn into a roller die. After four drawing processes, a 1.2 mm finished welding wire is obtained. The welding wire is then surface cleaned and dried, and then wound to form the finished welding wire.
[0053] Example 2
[0054] The components and contents of the welding wire in this embodiment are shown in Table 1. The preparation method of the welding wire in this embodiment is the same as that in Example 1.
[0055] Example 3
[0056] The components and contents of the welding wire in this embodiment are shown in Table 1. The preparation method of the welding wire in this embodiment is the same as that in Example 1.
[0057] Example 4
[0058] The components and contents of the welding wire in this embodiment are shown in Table 1. The preparation method of the welding wire in this embodiment is the same as that in Example 1.
[0059] Example 5
[0060] The components and contents of the welding wire in this embodiment are shown in Table 1. The preparation method of the welding wire in this embodiment is the same as that in Example 1.
[0061] Comparative Example 1
[0062] The components and contents of the welding wire in this comparative example are shown in Table 1. The preparation method is the same as that in Example 1.
[0063] Comparative Example 2
[0064] The components and contents of the welding wire in this comparative example are shown in Table 1. The preparation method is the same as that in Example 1.
[0065] Comparative Example 3
[0066] The components and contents of the welding wire in this comparative example are shown in Table 1. The preparation method is the same as that in Example 1.
[0067] Comparative Example 4
[0068] The components and contents of the welding wire in this comparative example are shown in Table 1. The preparation method is the same as that in Example 1.
[0069] Comparative Example 5
[0070] The components and contents of the welding wire in this comparative example are shown in Table 1. The preparation method is the same as that in Example 1.
[0071] Comparative Example 6
[0072] The components and contents of the welding wire in this comparative example are shown in Table 1. The preparation method is the same as that in Example 1.
[0073] Experimental Example 1
[0074] Welding wires with a diameter of 1.2 mm were prepared using the methods of Examples 1-5 and Comparative Examples 1-6, respectively. Welding tests were conducted using 95% Ar + 5% CO2 shielding. The test plates were 20 mm thick 1000 MPa grade marine engineering steel. The welding groove type was V-type, the welding current was 270 A, the welding voltage was 27 V, the welding speed was 340 mm / min, the preheating temperature was 80-120℃, and the post-heating temperature was 200-250℃ × 2 h. The mechanical properties of the deposited metals of the examples and comparative examples are shown in Table 2, and the welding conditions and crack notches (tested according to CB / T4364-2013 standard) are shown in Table 3. The microstructure of the deposited metals of Examples 1 and 2 is as follows: Figure 1 and 2 As shown.
[0075] Table 1
[0076]
[0077] Table 2
[0078]
[0079] from Figure 1 and 2 As can be seen from Table 2, the microstructure of the weld metal prepared by the welding wire described in this invention consists of interwoven lath martensite and lath bainite, exhibiting good strength-toughness matching and low crack sensitivity. Table 2 shows that the weld metal obtained from welding wires with compositions outside the scope of this invention has poor mechanical properties, and the weld metal microstructure contains a small amount of granular bainite.
[0080] Table 3
[0081]
[0082] As can be seen from Table 3, Examples 1-5 did not produce cracks under different welding conditions. Comparative Examples 1-2 and 6 produced cracks because they had relatively high strength and relatively low impact energy, making them prone to cracking. Comparative Examples 3-5 had low strength and low alloying element content, resulting in low sensitivity to cold cracking and making them less prone to cracking.
[0083] As can be seen from Tables 2 and 3, the welding wire prepared by the present invention has a tensile strength and yield strength of over 1000 MPa and does not produce cracks.
[0084] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A 1000MPa grade low-temperature high-toughness gas-shielded welding wire for marine engineering, characterized in that, The welding wire comprises the following components by weight percentage: C 0.091-0.12%, Si 0.3-0.46%, Mn 1.80-2.0%, Ni 1.5-2.68%, Cr 0.93-1.0%, Mo 0.91-1.0%, S≤0.005%, P≤0.005%, balance being Fe and unavoidable impurities; The welding wire has a tensile strength ≥1000MPa, a yield strength ≥1000MPa, an impact energy at -50℃ ≥60J, and an elongation ≥15%. The microstructure of the weld metal obtained by the welding wire consists of interwoven lath martensite and lath bainite.
2. The 1000MPa grade low-temperature high-toughness gas-shielded welding wire for marine engineering according to claim 1, characterized in that, The diameter of the welding wire is 1.15~1.2mm.
3. A method for preparing the welding wire according to claim 1 or 2, characterized in that, include: The raw material is vacuum smelted, bright drawn, and cleaned to obtain the welding wire.
4. A welding method for the welding wire according to claim 1 or 2, characterized in that, Welding is performed under 95% Ar + 5% CO2 protection.
5. The welding method according to claim 4, characterized in that, The welding current is 250~270A and the welding voltage is 25~27V.
6. The welding method according to claim 4, characterized in that, The welding speed is 320~350mm / min.
7. The welding method according to claim 4, characterized in that, The preheating temperature during welding is 80~120℃, and the preheating time is 1~2h.
8. The welding method according to claim 4, characterized in that, The post-weld heating temperature is 200~250℃, and the time is 1.5~2h.
9. The application of the welding wire according to claim 1 or 2 in welding 1000MPa grade marine engineering steel.