An automated seamless welding process and its application

Abstract

This invention discloses an automatic seamless welding process for stainless steel plates, comprising the following steps: S10) cutting the stainless steel plate to form a V-shaped bevel, cleaning the V-shaped bevel, and using the V-shaped bevel as the welding position; S20) feeding preheated welding rods to an automatic welding machine, and performing self-feeding arc welding on the welding position of the stainless steel plate by the automatic welding machine; wherein, the welding rod comprises a stainless steel skin and a flux-cored composition encapsulated within the stainless steel skin, the flux-cored composition comprising 40-60wt% silica ore powder, 20-50wt% iron powder, 3-6wt% nickel-manganese alloy, 3-10wt% bentonite, 1-6wt% fumed silica, 1-5wt% alumina, and 1-3wt% benzoin, totaling 100wt% by weight; S30) obtaining a seamless welded steel structural component; this invention can obtain a seamless welded steel structural component without microcracks, and the tensile strength and surface hardness performance of the weld position are excellent.

Description

Technical Field

[0001] This invention belongs to the field of steel plate processing, and specifically relates to an automatic seamless welding process. This application also relates to the application of this automatic seamless welding process. Background Technology

[0002] In certain steel structure applications (such as shipping containers or escalators), thicker steel plates (typically greater than 6mm) are often required to ensure structural strength. When welding these plates, seamless welding is typically used to ensure weld quality. However, conventional seamless welding processes are prone to microcracks, which can negatively impact the lifespan of the welded steel structural components.

[0003] Therefore, the applicant hopes to solve the above-mentioned technical problems by seeking technical solutions. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an automatic seamless welding process that can produce seamless welded steel structural components without the occurrence of hidden cracks, and with excellent tensile strength and surface hardness performance at the weld position.

[0005] The technical solution adopted in this invention is as follows:

[0006] An automated seamless welding process is applied to steel plates, wherein the steel plate is stainless steel plate, and the automated seamless welding process includes the following steps:

[0007] S10) Cut the stainless steel sheet to form a V-shaped bevel, clean the V-shaped bevel, and use the V-shaped bevel as the welding position.

[0008] S20) The preheated welding rod is fed into an automatic welding machine, which performs self-feeding arc welding on the welding position of the stainless steel plate. The welding rod comprises a stainless steel coating and a flux-cored composition encapsulated within the stainless steel coating. The flux-cored composition comprises 40-60 wt% silica ore powder, 20-50 wt% iron powder, 3-6 wt% nickel-manganese alloy, 3-10 wt% bentonite, 1-6 wt% fumed silica, 1-5 wt% alumina, and 1-3 wt% benzoin, totaling 100 wt%.

[0009] S30) to obtain seamless welded steel structural components.

[0010] Preferably, the core composition comprises 45-55 wt% silica ore powder, 30-45 wt% iron powder, 3-6 wt% nickel-manganese alloy, 3-5 wt% bentonite, 1-3 wt% fumed silica, 1-5 wt% alumina, and 1-3 wt% benzoin, totaling 100 wt%, and / or the stainless steel sheath is made of the same material as the stainless steel sheet.

[0011] Preferably, the stainless steel sheet comprises 16-18 wt% chromium, 6-7 wt% manganese, 2-4 wt% nickel, 0.2-0.5 wt% silicon, 0.1-0.2 wt% silver, 0.1-0.2 wt% nitrogen, with the remainder being iron and unavoidable impurities.

[0012] Preferably, the flux-cored composition accounts for 15-25 wt% of the electrode by weight.

[0013] Preferably, in the self-powered arc welding of step S20), the welding current is proportional to the thickness of the stainless steel plate and the diameter of the welding electrode.

[0014] Preferably, in the self-powered arc welding of step S20), the number of welding layers is selected according to the thickness of the stainless steel plate and the diameter of the welding rod.

[0015] Preferably, the thickness of the stainless steel sheet is 6-12mm, and the diameter of the welding rod is 2.5-2.8mm.

[0016] Preferably, before step S20), the preheating method of the welding rod is as follows: the welding rod is heated and sintered at a temperature of not less than 450°C for at least 1 hour; then it is kept at a temperature of 80-120°C.

[0017] Preferably, the inclination angle of the V-shaped bevel is 50-65°.

[0018] Preferably, the automatic seamless welding process is applied as an automatic seamless welding process for container steel structures or escalator steel structures.

[0019] This application first selects stainless steel sheet as the processing material for the steel structure, and uses a V-groove as the welding position. Then, a welding electrode composed of a stainless steel skin and a specific flux-cored composition (specifically including 40-60 wt% silica ore powder, 20-50 wt% iron powder, 3-6 wt% nickel-manganese alloy, 3-10 wt% bentonite, 1-6 wt% fumed silica, 1-5 wt% alumina, and 1-3 wt% benzoin) is used. When the preheated welding electrode is used to perform self-feeding arc welding on the V-groove of the stainless steel sheet using an automatic welding machine, the applicant was surprised to find that a seamless welded steel structure was obtained, with no hidden cracks, and the tensile strength and surface hardness performance of the welded position were excellent. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the operation steps of the automatic seamless welding process according to a specific embodiment of this application. Detailed Implementation

[0021] This invention discloses an automatic seamless welding process applied to steel plates, specifically stainless steel plates. (See also...) Figure 1 As shown, the automated seamless welding process includes the following steps:

[0022] S10) Cut the stainless steel sheet to form a V-shaped bevel, clean the V-shaped bevel, and use the V-shaped bevel as the welding position. Preferably, the inclination angle of the V-shaped bevel is 50-65°.

[0023] Preferably, before performing step S20), the welding rod is preheated by placing it at a temperature of not less than 450°C (preferably 480-550°C) for at least 1 hour (preferably 1-3 hours); and then keeping it at a temperature of 80-120°C.

[0024] S20) The preheated welding rod is fed into an automatic welding machine, which performs self-feeding arc welding on the welding position of the stainless steel plate. The welding rod comprises a stainless steel coating and a flux-cored composition encapsulated within the stainless steel coating. The flux-cored composition comprises 40-60 wt% silica ore powder, 20-50 wt% iron powder, 3-6 wt% nickel-manganese alloy, 3-10 wt% bentonite, 1-6 wt% fumed silica, 1-5 wt% alumina, and 1-3 wt% benzoin, totaling 100 wt%. More preferably, in this embodiment... In the formula, the flux core composition includes 45-55 wt% silica ore powder, 30-45 wt% iron powder, 3-6 wt% nickel-manganese alloy, 3-5 wt% bentonite, 1-3 wt% fumed silica, 1-5 wt% alumina, and 1-3 wt% benzoin, totaling 100 wt% by weight. Preferably, in this embodiment, the flux core composition accounts for 15-25 wt% of the electrode by weight, more preferably 16-20 wt%. In actual manufacturing, the flux core composition is placed inside a stainless steel sheath, rolled and sealed by welding.

[0025] Preferably, in this embodiment, to ensure the structural strength of the welded position, the material of the stainless steel cladding is the same as that of the stainless steel sheet. Specifically, preferably, in this embodiment, the stainless steel sheet comprises 16-18 wt% chromium, 6-7 wt% manganese, 2-4 wt% nickel, 0.2-0.5 wt% silicon, 0.1-0.2 wt% silver, and 0.1-0.2 wt% nitrogen, with the remainder being iron and unavoidable impurities. The stainless steel sheet and stainless steel cladding involved in this embodiment can be directly purchased from steel companies.

[0026] Preferably, in the self-powered arc welding of this step S20), the welding current is proportional to the thickness of the stainless steel plate and the diameter of the welding rod; the number of welding layers is selected according to the thickness of the stainless steel plate and the diameter of the welding rod; specifically preferably, in this embodiment, the thickness of the stainless steel plate is 6-12mm and the diameter of the welding rod is 2.5-2.8mm.

[0027] S30) to obtain seamless welded steel structural components.

[0028] Preferably, the automatic seamless welding process described above is applied as an automatic seamless welding process for container steel structures or escalator steel structures; of course, it can also be applied as an automatic seamless welding process for other box steel structures or other product steel structures, and this application does not impose any limitation on it.

[0029] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0030] Example 1: An automated seamless welding process for container plates, comprising the following steps:

[0031] S10) Stainless steel sheet produced by Baosteel (the stainless steel sheet composition includes 16-18wt% chromium, 6-7wt% manganese, 2-4wt% nickel, 0.2-0.5wt% silicon, 0.1-0.2wt% silver, 0.1-0.2wt% nitrogen, and the remaining components are iron and unavoidable impurities, with a thickness of 6.5mm) is selected. The stainless steel sheet is cut to form a V-shaped bevel with an inclination angle of 58°. The V-shaped bevel is cleaned and used as the welding position.

[0032] The welding rod is preheated by heating it at 500-520℃ for 1.5 hours, and then holding it at 80-120℃.

[0033] S20) The preheated welding rod is fed into the automatic welding machine, which performs self-feeding arc welding on the welding position of the stainless steel plate (3 welding layers, welding current 116A). The welding rod consists of a stainless steel skin (the same material as the stainless steel plate) and a flux-cored composition encapsulated in the stainless steel skin. The flux-cored composition consists of 49wt% silica ore powder, 40wt% iron powder, 4wt% nickel-manganese alloy, 4wt% bentonite, 1wt% fumed silica, 1wt% alumina, and 1wt% benzoin, totaling 100wt% by weight. The flux-cored composition accounts for 18wt% of the weight of the welding rod, and the diameter of the welding rod is 2.6mm.

[0034] S30), to obtain seamless welded container panels.

[0035] Example 2: The remaining technical solutions of Example 2 are the same as those of Example 1, except that in step S20), the flux core composition includes 45wt% silica ore powder, 35wt% iron powder, 5wt% nickel-manganese alloy, 4wt% bentonite, 5wt% fumed silica, 4wt% alumina and 2wt% benzoin, totaling 100wt% by weight; the flux core composition accounts for 20wt% of the electrode by weight, and the electrode diameter is 2.5mm.

[0036] Example 3: The remaining technical solutions of Example 3 are the same as those of Example 1, except that the thickness of the stainless steel plate is 7.2 mm; and in this step S20), the flux-cored composition includes 50 wt% silica ore powder, 37 wt% iron powder, 6 wt% nickel-manganese alloy, 3 wt% bentonite, 1 wt% fumed silica, 2 wt% alumina and 1 wt% benzoin, totaling 100 wt% by weight; the flux-cored composition accounts for 22 wt% of the electrode by weight, the electrode diameter is 2.8 mm; the number of welding layers is 3, and the welding current is 120 A.

[0037] Example 4: An automatic seamless welding process for handrail panels, comprising the following steps:

[0038] S10) Stainless steel sheet produced by Baosteel (the stainless steel sheet composition includes 16-18wt% chromium, 6-7wt% manganese, 2-4wt% nickel, 0.2-0.5wt% silicon, 0.1-0.2wt% silver, 0.1-0.2wt% nitrogen, and the remaining components are iron and unavoidable impurities, with a thickness of 7.5mm) is selected. The stainless steel sheet is cut to form a V-shaped bevel with an inclination angle of 60°. The V-shaped bevel is cleaned and used as the welding position.

[0039] The welding electrode is preheated by heating it at 530℃ for 2 hours; then it is kept at 80-120℃.

[0040] S20) The preheated welding rod is fed into the automatic welding machine, which performs self-feeding arc welding on the welding position of the stainless steel plate (3 welding layers, welding current 125A). The welding rod consists of a stainless steel skin (the same material as the stainless steel plate) and a flux-cored composition encapsulated in the stainless steel skin. The flux-cored composition consists of 49wt% silica ore powder, 40wt% iron powder, 4wt% nickel-manganese alloy, 4wt% bentonite, 1wt% fumed silica, 1wt% alumina, and 1wt% benzoin, totaling 100wt% by weight. The flux-cored composition accounts for 18wt% of the weight of the welding rod, and the diameter of the welding rod is 2.6mm.

[0041] S30) to obtain seamless welded handrail panels.

[0042] Comparative Example 1: The remaining technical solutions of Comparative Example 1 are the same as those of Example 1, except that in step S20), the core composition includes 50wt% silica ore powder and 50wt% iron powder, with a total weight of 100wt%.

[0043] Comparative Example 2: The remaining technical solutions of Comparative Example 2 are the same as those of Example 1, except that in this step S20), stainless steel welding rods are used.

[0044] Comparative Example 3: The remaining technical solutions of Comparative Example 3 are the same as those of Example 1, except that the stainless steel sheet is made of martensitic stainless steel.

[0045] Comparative Example 4: The remaining technical solutions of Comparative Example 4 are the same as those of Example 1, except that the stainless steel coating of the welding rod is made of martensitic stainless steel.

[0046] Comparative Example 5: The remaining technical solutions of Comparative Example 5 are the same as those of Example 1, except that the welding electrode is the seamless flux-cored welding wire disclosed in CN106736049 A.

[0047] To verify the implementation effects of this embodiment and the comparative example, after welding, each embodiment and the comparative example were subjected to the same annealing conditions (annealing treatment for 2 hours, annealing temperature of 250-350℃) to relieve stress. Then, the plates at the welding positions were cut. Please refer to the performance comparison shown in Table 1 below:

[0048] Table 1

[0049] Weld appearance - visual inspection Tensile strength (MPa) - performed at room temperature Surface hardness (HV) - performed at room temperature Example 1 Seamless effect ≥680 ≥790 Example 2 Seamless effect ≥680 ≥790 Example 3 Seamless effect ≥680 ≥790 Example 4 Seamless effect ≥680 ≥790 Comparative Example 1 The weld seam is quite noticeable. <600 <750 Comparative Example 2 The weld seam is quite noticeable. <600 <750 Comparative Example 3 The weld seam is quite noticeable. <600 <750 Comparative Example 4 The weld seam is quite noticeable. <600 <750 Comparative Example 5 Seamless effect <600 <750

[0050] The above performance comparison further confirms that the embodiments of this application have obtained seamless welded steel structural components without any hidden cracks, and the tensile strength and surface hardness performance at the welded positions are excellent.

[0051] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0052] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An automated seamless welding process applied to steel plates, characterized in that, The steel plate is stainless steel, and the stainless steel plate comprises 16-18 wt% chromium, 6-7 wt% manganese, 2-4 wt% nickel, 0.2-0.5 wt% silicon, 0.1-0.2 wt% silver, and 0.1-0.2 wt% nitrogen, with the remainder being iron and unavoidable impurities; the automatic seamless welding process includes the following steps: S10) Cut the stainless steel sheet to form a V-shaped bevel, clean the V-shaped bevel, and use the V-shaped bevel as the welding position. S20) The preheated welding rod is fed into the automatic welding machine, which performs self-feeding arc welding on the welding position of the stainless steel plate. The welding rod comprises a stainless steel coating and a flux-cored composition encapsulated within the stainless steel coating. The flux-cored composition comprises 40-60 wt% silica ore powder, 20-50 wt% iron powder, 3-6 wt% nickel-manganese alloy, 3-10 wt% bentonite, 1-6 wt% fumed silica, 1-5 wt% alumina, and 1-3 wt% benzoin, totaling 100 wt%. The stainless steel coating is made of the same material as the stainless steel plate. S30) to obtain seamless welded steel structural components.

2. The automatic seamless welding process according to claim 1, characterized in that, The core composition comprises 45-55 wt% silica ore powder, 30-45 wt% iron powder, 3-6 wt% nickel-manganese alloy, 3-5 wt% bentonite, 1-3 wt% fumed silica, 1-5 wt% alumina, and 1-3 wt% benzoin, totaling 100 wt%.

3. The automatic seamless welding process according to claim 1, characterized in that, The flux-cored composition accounts for 15-25 wt% of the weight of the welding electrode.

4. The automatic seamless welding process according to claim 1, characterized in that, In the self-powered arc welding of step S20), the welding current is proportional to the thickness of the stainless steel plate and the diameter of the welding electrode.

5. The automatic seamless welding process according to claim 1, characterized in that, In the self-powered arc welding of step S20), the number of welding layers is selected according to the thickness of the stainless steel plate and the diameter of the welding rod.

6. The automatic seamless welding process according to claim 4 or 5, characterized in that, The thickness of the stainless steel sheet is 6-12mm, and the diameter of the welding rod is 2.5-2.8mm.

7. The automatic seamless welding process according to claim 1, characterized in that, Before step S20), the preheating method of the welding rod is as follows: the welding rod is heated and sintered at a temperature of not less than 450°C for at least 1 hour; then it is kept at a temperature of 80-120°C.

8. The automatic seamless welding process according to claim 1, characterized in that, The inclination angle of the V-shaped bevel is 50-65°.

9. The automatic seamless welding process according to claim 1, characterized in that, The automatic seamless welding process is applied as an automatic seamless welding process for container steel structures or escalator steel structures.

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