Marine high-efficiency and environmentally friendly submerged arc welding sintering flux and preparation method thereof

Abstract

The marine high-efficiency and environmentally friendly submerged arc welding sintering flux of the present invention has magnesium oxide (MgO), fluorite (CaF2), and silicon dioxide (SiO2) as main components, wherein the content of the main components reaches more than 80%. The flux formula contains relatively high magnesium oxide (MgO) and fluorite (CaF2), so that the solidification time of the molten pool is short, which is conducive to achieving the best balance between the mechanical properties of the weld and the welding processability. The magnesium oxide (MgO) and fluorite (CaF2) content in the flux is high, so that the flux can carry a large current, and combined with a certain amount of silicon dioxide (SiO2), the flux is suitable for a larger welding voltage. At the same time, a small amount of alloy powder is added to the flux formula to protect alloy elements such as silicon and manganese, which can inhibit the coarseness of the weld structure and increase the crack resistance of the weld.

Description

Technical Field

[0001] The present invention relates to the technical field of high-efficiency submerged arc welding for shipbuilding, and in particular to a ship-use high-efficiency and environmentally friendly submerged arc welding sintered flux used in a medium-thick plate submerged arc automatic welding process and a preparation method thereof. Background Art

[0002] With the development of shipbuilding industry, the demand for container ships, bulk carriers, etc. is increasing. Submerged arc automatic welding has also developed from thin plate (t=7-18mm) welding to thick plate (t=15-55mm) submerged arc welding, and the amount of welding required for production is constantly increasing.

[0003] According to the flux and wire combination currently used in submerged arc welding, for example, welding wire H10Mn 2 , diameters are Φ2.0mm, Φ3.0mm, Φ4.0mm, Φ5.0mm, matched with SJ101 sintered flux, and in order to ensure the mechanics of welding, especially the impact toughness, the welding current is normally less than 800A, and it is necessary to adopt the reverse carbon planing, root cleaning process, and small current multi-pass welding process parameters. This welding method has the disadvantages of low welding efficiency, toxic gas, particle dust, noise, arc light, etc. produced during welding, and pollutes the environment. Foreign shipbuilding processes, such as Japan and South Korea, have successively adopted new processes such as reverse carbon planing, no root cleaning, and welding wire combination, while my country is still blank in this regard.

[0004] At present, the welding technology difficulties of environmentally friendly submerged arc welding flux wire combination lie in the following aspects:

[0005] 1. When the diameter of the submerged arc welding wire reaches Φ6.4mm, the welding line energy is large, the welding current I=800~1200A, and the welding steel plate t≤30mm is required. According to the normal design plan, when welding the front and back sides in a single pass, how to ensure that there are no defects such as pores, slag inclusions, and burn-through on the back side, and meet the mechanical properties of the welded joints required by the design, especially the toughness of the welding. Because in general, as the welding current increases, the welding structure becomes coarse, which is easy to cause harmful precipitation and cannot meet the mechanical properties requirements of welding.

[0006] 2. Develop a flux that matches H10Mn2 and Φ6.4mm welding wire diameter, which can not only ensure the reverse side forming and no carbon gouging, but also ensure that the mechanical properties of the weld can meet 3Y (-20℃, impact energy ≥34), which is the technical key to high-efficiency submerged arc welding. Summary of the invention

[0007] One of the technical problems to be solved by the present invention is to overcome technical difficulties, break the foreign monopoly and provide a marine high-efficiency and environmentally friendly submerged arc welding sintered flux, whose welding wire matches the diameter of Φ6.4mm, H10Mn2, to replace the foreign Japanese and Korean sintered flux welding wire, while meeting the submerged arc welding process performance of domestic medium and thick plates (t=10-55mm), ensuring the excellent mechanical properties of the welded joints, and the mechanical properties meet the requirements of the classification society specifications.

[0008] The second technical problem to be solved by the present invention is to provide a marine high-efficiency and environmentally friendly submerged arc welding sintering flux that matches the diameter of Φ6.4mm, H10Mn2, welding current I=800~1200A, and can carry a large line energy.

[0009] The third technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned marine high-efficiency and environmentally friendly submerged arc welding sintered flux.

[0010] The technical problem to be solved by the present invention can be achieved by the following technical solutions:

[0011] The marine high-efficiency and environmentally friendly submerged arc welding sintering flux of the present invention is composed of magnesium oxide (MgO), fluorite (CaF 2 ), silicon dioxide (SiO 2 ) is the main component, of which the content of the main component is more than 80%. The flux formula contains high magnesium oxide (MgO) and fluorite (CaF2), which shortens the solidification time of the molten pool and is conducive to achieving the best balance between the mechanical properties of the weld and the welding processability. 2 ) content is high, providing the flux with the ability to carry large currents, combined with a certain amount of silicon dioxide (SiO 2 ), making the flux suitable for a larger welding voltage. At the same time, a small amount of alloy powder is added to the flux formula to protect alloy elements such as silicon and manganese, which can inhibit the coarseness of the weld structure and increase the weld's crack resistance.

[0012] The marine high-efficiency and environmentally friendly submerged arc welding sintered flux of the present invention is prepared by mixing, granulating, drying and sintering magnesia, fluorite, silicon dioxide, zircon sand, iron powder, marble, ferrosilicon, ferromanganese, ferromolybdenum, ferrotitanium, aluminum oxide and 20% potassium sodium water glass. The mass percentages of the raw materials are as follows:

[0013] Magnesia 30-40%, fluorite 25-35%, silicon dioxide 10-20%, zircon sand 2-4%, iron powder 5-10%, ferrosilicon 1-2%, ferromanganese 1.0-2.0%, ferromolybdenum 0.5-1.0%, ferrotitanium 0.5-1.0%, bauxite 20-30%, of which the potassium-sodium ratio of potassium-sodium water glass is 1:1, the modulus is 2.5, and the Baume degrees is 40-45.

[0014] In a preferred embodiment of the present invention, the magnesia is: MgO≥90%, SiO 2 ≤5%, S≤0.03%, P≤0.08%. CaO≤1%.

[0015] In a preferred embodiment of the present invention, the fluorite is: CaF 2 ≥90%,SiO 2 ≤8.5% S≤0.045%,P≤0.02%.

[0016] In a preferred embodiment of the present invention, the zircon sand is: ZrO 2 ≥60%,SiO 2 ≤25%,S≤0.05%,P≤0.05%.

[0017] In a preferred embodiment of the present invention, the ferrosilicon is: Si≥75%, S≤0.02%, P≤0.04%, and the remainder is iron powder.

[0018] In a preferred embodiment of the present invention, the ferromanganese is: Mn≥80%, S≤0.02%, P≤0.3%.

[0019] In a preferred embodiment of the present invention, the ferromolybdenum is: Mo ≥ 45%, S ≤ 0.15%, P ≤ 0.1%.

[0020] In a preferred embodiment of the present invention, the titanium iron is: Ti ≥ 30-45%, S ≤ 0.03%, P ≤ 0.05%.

[0021] In a preferred embodiment of the present invention, the iron powder is: Fe≥98%, SiO 2 ≤25%, S≤0.025%, P≤0.02%.

[0022] In a preferred embodiment of the present invention, the marble is: CaCO 3 ≥95%, S≤0.03%, P≤0.03%.

[0023] In a preferred embodiment of the present invention, the raw materials are mixed by the following raw materials in mass percentage: 35% magnesia, 30% fluorite, 10% silicon dioxide, 3% zircon sand, 10% iron powder, 2% marble, 2% ferrosilicon, 1% ferromanganese, 1.5% ferromolybdenum, 0.5% ferrotitanium and 3.5% bauxite.

[0024] The method for producing the marine high-efficiency and environmentally friendly submerged arc welding sintered flux of the present invention comprises the following steps:

[0025] (1) Weigh various raw materials in the solder in proportion to the actual required particle size;

[0026] (2) After screening, dry mixing is performed according to weight ratio;

[0027] (3) After mixing, add 20% potassium sodium water glass for wet stirring after sufficient mixing;

[0028] (4) Granulation is performed using a granulator;

[0029] (5) Drying the granulated particles in a low temperature furnace at 200°C-400°C;

[0030] (6) The dried flux is sieved to 10-60 mesh;

[0031] (7) Sintering in a high temperature furnace at 600°C-800°C;

[0032] (8) Then cool and weigh;

[0033] (9) Then transfer to a well-sealed, moisture-proof container for storage;

[0034] (10) Considering the high anti-destruction strength during transportation, it is chosen to be transferred to the iron tube;

[0035] (11) Finally, we provide the products to customers for welding with guaranteed quality and quantity.

[0036] The beneficial effects of the present invention are:

[0037] The flux of the invention completely matches the H10Mn2 welding wire with a diameter of Φ6.4mm, is used for submerged arc welding of carbon steel and low alloy steel, can completely replace the performance of imported similar products, meet the submerged arc welding process with a plate thickness of t=55mm or less, meet the requirements of classification society specifications on the physical and chemical properties of welded joints, and reduce dependence on foreign fluxes; compared with the traditional SJ101 sintering welding matching the H10Mn2 welding wire with a diameter of Φ6.4mm, the welding efficiency can be improved, and carbon planing is eliminated, thereby reducing the damage to the environment and personnel health caused by dust and noise caused by carbon planing, thereby meeting the requirements of high efficiency and environmental protection.

[0038] The flux of the present invention contains a high content of magnesium oxide and a large amount of fluoride (MgO+CaF2), which ensures that a large amount of volatile gas is generated in the molten pool in the liquid state, which is conducive to the full stirring of the liquid molten pool, reduces the risk of coarse weld structure, and can also reduce the addition of non-ferrous metal oxide manganese ore harmful to the human body in the flux. In addition, the addition of CO2 in the welding molten pool reduces the proportion of [H] content in the molten pool, reduces the [H] in the weld, and reduces the risk of delayed cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of welding joint groove processing.

[0040] Figure 2 This is a metallographic diagram of the welding joint numbered M191128-2.

[0041] Figure 3 This is a metallographic diagram of the welding joint numbered 200115-30. DETAILED DESCRIPTION

[0042] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the claims of the present invention.

[0043] The flux of each embodiment is prepared from solder and 20% potassium sodium water glass (potassium sodium ratio 1:1, modulus 2.8, Baume degree 40-45) by weight, wherein the solder is mixed with the following raw materials in mass percentage, and the specific preparation method is as follows:

[0044] Weigh the raw materials in the solder in proportion to the actual required particle size, sieve, feed the ingredients according to the weight ratio, mix them thoroughly, add 20% potassium sodium water glass for wet stirring, and then use a granulator to granulate, and dry the granulated mixed granular flux at 200℃-300℃ in a low-temperature furnace. The dried welding machine is sieved to 12-48 mesh, and then sintered at 600℃-800℃ in a high-temperature furnace. Finally, it is sieved, cooled, and loaded into an iron tube with good sealing, moisture-proof performance, and high anti-destruction strength during storage and transportation for use in welding production.

[0045] The solder weight ratio of each embodiment is shown in Table 1

[0046] Table 1

[0047] Element Example 1 (Kg) Example 2 (Kg) Example 3 (Kg) Magnesia 30 35 40 fluorite 35 30 25 Silicon dioxide 20 10 15 Zircon sand 2 4 5 Iron Fan 5 10 8 <![CDATA[CaCO 3 ]]> 3 5 2 Ferrosilicon 2 105 1 Ferromolybdenum 1 0.5 0.8 Ferromanganese 105 2 1 Ferrotitanium 1 0.8 0.5

[0048] The submerged arc sintering flux obtained in Examples 1-3 in Table 1 of the present invention was used to match the domestic Φ6.4mm, H10Mn2 welding wire to carry out welding tests. The detailed test results are as follows:

[0049] Table 2

[0050] Device Name Welding machine signal Quantity (unit) Manufacturer M Submerged Arc Welding Equipment MZ-1250(DC) 1 Shanghai Shiwei Welding Industry Co., Ltd.

[0051] The specifications and composition of welding wire are shown in Table 3

[0052] Table 3

[0053]

[0054] Test steel plate

[0055] The grade and specification of the test steel plate material DH36 are shown in Table 4

[0056] Table 4

[0057] Test No. grade C Si Mn P S Example 1 0.16 0.32 1.35 0.015 0.0034 Example 2 T=30mm 0.15 0.27 1.35 0.014 0.0040 Example 3 0.14 0.25 1.29 0.013 0.006

[0058] The properties of the welded joint are shown in Table 5:

[0059] Table 5

[0060]

[0061] The properties of the welded joint are shown in Table 6

[0062] Table 6

[0063]

[0064] Analysis of test results:

[0065] It can be seen from the table that the present invention is used for double-sided single-pass submerged arc welding of DH36, t=30mm ship plate, and can obtain good mechanical properties, meet the evaluation requirements of ship DH36, and the strength and elongation of the weld, impact toughness, have a large margin. From the chemical composition point of view, C, Mn, Si in the weld are stable and reasonable.

[0066] The above test results show that the flux of the present invention contains a large amount of magnesium oxide, fluorite, bauxite, etc., which can not only obtain excellent welding process performance, but also obtain stable weld metal chemical composition and structure, ensuring stable performance.

Claims

1. A marine high-efficiency and environmentally friendly submerged arc welding sintered flux with a matching diameter of Φ6.4mm, H10Mn2, and a welding current of I=800-1200A, characterized by: It is made of magnesia, fluorite, silicon dioxide, zircon sand, iron powder, marble, ferrosilicon, ferromanganese, ferromolybdenum, ferrotitanium, aluminum oxide and 20% potassium sodium water glass through mixing, granulation, drying and sintering. The mass percentages of the raw materials used are as follows: 30-40% magnesia, 25-35% fluorite, 10-20% silicon dioxide, 2-4% zircon sand, 5-10% iron powder, 1-2% ferrosilicon, 1.0-2.0% ferromanganese, 0.5-1.0% ferromolybdenum, 0.5-1.0% ferrotitanium, 20-30% bauxite; the potassium-sodium ratio of potassium-sodium water glass is 1:1, the modulus is 2.5, and the Baume degree is 40-45; The magnesia is: MgO ≥ 90%, SiO2 ≤ 5%, S ≤ 0.03%, P ≤ 0.08%, CaO ≤ 1%; The fluorite is: CaF2≥90%, SiO2≤8.5%, S≤0.045%, P≤0.02%; The zircon sand is: ZrO2≥60%, SiO2≤25%, S≤0.05%, P≤0.02%; The ferrosilicon is: Si ≥ 75%, S ≤ 0.02%, P ≤ 0.04%, and the balance is iron powder; The ferromanganese is: Mn ≥ 80%, S ≤ 0.02%, P ≤ 0.3%; The ferromolybdenum is: Mo ≥ 45%, S ≤ 0.15%, P ≤ 0.1%; The titanium iron is: Ti ≥ 30-45%, S ≤ 0.03%, P ≤ 0.05%; The iron powder is: Fe ≥ 98%, SiO2 ≤ 25%, S ≤ 0.025%, P ≤ 0.02%; The marble is: CaCO3≥95%, S≤0.03%, P≤0.03%.

2. The marine high-efficiency and environmentally friendly submerged arc welding sintered flux as claimed in claim 1 is characterized by: The raw materials used are mixed by the following mass percentages: Magnesia 35%, fluorite 30%, silicon dioxide 10%, zircon sand 3%, iron powder 10%, marble 2%, ferrosilicon 2%, ferromanganese 1%, ferromolybdenum 1.5%, ferrotitanium 0.5%, and aluminum oxide 3.5%.

3. A method for producing a marine high-efficiency and environmentally friendly submerged arc welding sintered flux according to claim 1 or 2, characterized in that: The steps include: (1) Weigh various raw materials in the solder in proportion to the actual required particle size; (2) After screening, dry mixing is performed according to weight ratio; (3) After mixing, add 20% potassium sodium water glass for wet stirring after sufficient mixing; (4) Granulation is performed using a granulator; (5) drying the granulated particles at 200°C-400°C in a low temperature furnace; (6) The dried flux is sieved to 10-60 mesh; (7) Sintering in a high temperature furnace at 600°C-800°C; (8) Then cool and weigh; (9) Then transfer to a well-sealed, moisture-proof container for storage; (10) Considering the high anti-destruction strength during transportation, it is chosen to be transferred into iron drums; (11) Finally, the products are provided to customers for welding with guaranteed quality and quantity.

Images