Flux-cored wire for marine crack arrest steel and preparation method and application of flux-cored wire

Abstract

The invention provides a flux-cored wire for marine crack arrest steel and a preparation method and application of the flux-cored wire, and particularly relates to the technical field of welding materials. The flux-cored wire comprises a steel strip and a flux core filled in the steel strip, and the flux core comprises the following components in parts by weight: 10-15 parts of rutile, 5-6 parts of quartz, 2-4 parts of ferrotitanium, 20-40 parts of sodium fluoride, 20-40 parts of potassium feldspar, 6-18 parts of manganese-silicon alloy, 4-8 parts of low-carbon ferromanganese, 1.5-2.5 parts of magnesium powder, 1.5-2 parts of rare earth ferrosilicon, 0.2-0.4 part of ferroboron, 1-2 parts of metallic nickel and 1.5-6 parts of iron powder. The ship crack arrest steel flux-cored wire has the advantages of being high in strength, good in low-temperature toughness, good in crack resistance, high in deposition rate, stable in electric arc, little in splashing, easy in slag removal and attractive in weld joint forming, and is suitable for welding of crack arrest steel at a core structure part of an ultra-large container ship.

Description

Technical Field

[0001] The invention relates to the technical field of welding materials, and in particular to a flux-cored welding wire for ship crack arrest steel and a preparation method and application thereof. Background Art

[0002] Ultra-large container ships (referring to container ships with a capacity of more than 10,000 TEU (20-foot equivalent unit)) are one of the three main ship types in the world. Ultra-large container ships need to bear the huge weight of containers during transportation. Under the action of waves, they are very prone to twisting and cracking. To prevent the above situation from happening, ultra-large container ships use EH40 and EH47 grade high-strength crack-arresting steel plates, which have large thickness, high strength, extremely strong low-temperature toughness and crack resistance. This high-strength crack-arresting steel plate is generally used in the deck, side top column plate and hatch coaming, where the whole ship is subjected to the greatest stress and load intensity. It is the most critical position for the strength and toughness verification of the whole ship, and it is also one of the core structural components of ultra-large container ships. Ultra-large container ships use EH40 and EH47 grade high-strength crack-arresting steel plates, which require welding materials to have the characteristics of high strength, high toughness, high crack resistance and good weldability, while conventional welding materials cannot meet this welding requirement.

[0003] Therefore, there is an urgent need to develop a welding material that can match the high-strength crack-arresting steel plate. Summary of the invention

[0004] In view of the defects of the prior art, the present invention provides a flux-cored welding wire for ship crack arrest steel and a preparation method and application thereof to meet the welding requirements of high-strength crack arrest steel.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a flux-cored welding wire for ship crack arrest steel, the flux-cored welding wire comprising a steel strip and a flux core filled in the steel strip, the flux core comprising the following components in parts by weight: 10 to 15 parts of rutile, 5 to 6 parts of quartz, 2 to 4 parts of ferrotitanium, 20 to 40 parts of sodium fluoride, 20 to 40 parts of potassium feldspar, 6 to 18 parts of manganese silicon alloy, 4 to 8 parts of low-carbon ferromanganese, 1.5 to 2.5 parts of magnesium powder, 1.5 to 2 parts of rare earth ferrosilicon, 0.2 to 0.4 parts of ferroboron, 1 to 2 parts of metallic nickel, and 1.5 to 6 parts of iron powder.

[0006] In one example of the present invention, the ferrotitanium is 30# ferrotitanium; the manganese content in the manganese silicon alloy is 62-67wt%, and the silicon content is 20-23wt%; the manganese content in the low-carbon ferromanganese is ≥80wt%, and the carbon content is ≤0.7wt%; the rare earth ferrosilicon adopts rare earth ferrosilicon with the grade of RESiFe-32Ce; the ferroboron adopts ferroboron with the grade of FeB22C0.05.

[0007] In one example of the present invention, the titanium dioxide content in the rutile is ≥95wt%, the sulfur content is ≤0.010wt%, and the phosphorus content is ≤0.010wt%; the silicon dioxide content in the quartz is ≥97wt%, the sulfur content is ≤0.040wt%, and the phosphorus content is ≤0.040wt%; the silicon dioxide content in the potassium feldspar is 63-73wt%, and the aluminum oxide content is 15-22wt%.

[0008] In an example of the present invention, the purity of the sodium fluoride is ≥98%; the purity of the magnesium powder is ≥98%; the purity of the iron powder is ≥99%; and the purity of the metal nickel is ≥99%.

[0009] In one example of the present invention, the particle size of each component in the drug core is 60-80 mesh.

[0010] In an example of the present invention, the filling amount of the flux core accounts for 17% to 20% of the total weight of the flux cored welding wire.

[0011] In an example of the present invention, the steel strip is a carbon steel strip.

[0012] In an example of the present invention, the diameter of the flux-cored welding wire is 1.2-1.6 mm.

[0013] The present invention also provides a method for preparing a flux-cored welding wire for marine crack arrest steel, comprising the following steps:

[0014] Mixing the components of the drug core evenly to prepare the drug core;

[0015] The steel strip is cut longitudinally and then rolled into a U-shaped groove;

[0016] Filling the drug core into the U-shaped groove;

[0017] The steel strip filled with the flux core is closed rolled, and is drawn and reduced to a preset diameter to obtain a flux cored welding wire for marine crack arrest steel.

[0018] The present invention also provides an application of a flux-cored welding wire for ship crack arrest steel, wherein the flux-cored welding wire for ship crack arrest steel is used for welding crack arrest steel of a core structure of an ultra-large container ship.

[0019] The flux-cored welding wire for crack arrest steel provided by the present invention uses the Mn-Si-Ti-B alloy system, and utilizes the microalloying effect of Ti-B and the purification effect of rare earth elements to promote the formation of acicular ferrite, further improving the toughness of the weld, so that the weld metal has excellent impact toughness at low temperatures. The addition of rare earth elements can improve the high-temperature corrosion resistance and impact toughness of the weld metal; the addition of potassium feldspar and rutile can form a short slag effect, which is conducive to the formation of the weld. Therefore, the flux-cored welding wire for crack arrest steel used in the present invention has the advantages of high strength, good low-temperature toughness, good crack resistance and high deposition rate, stable arc, less spatter, easy slag removal, and beautiful weld formation, and is suitable for the welding of crack arrest steel of the core structure of ultra-large container ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 The present invention is a flow chart of the method for preparing flux-cored welding wire for marine crack arrest steel. DETAILED DESCRIPTION

[0022] The following is an explanation of the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the features in the following embodiments and the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturers.

[0023] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are familiar to those skilled in the art and the description of the present invention, and any methods, equipment and materials of the prior art similar or equivalent to the methods, equipment and materials described in the embodiments of the present invention can also be used to implement the present invention.

[0024] The raw materials used in the present invention can be obtained through general commercial means. It should be noted that, unless otherwise specified, "%" and "wt%" described herein refer to "mass percentage".

[0025] The present invention provides a flux-cored welding wire for ship crack arrest steel and a preparation method and application thereof. The high-strength flux-cored welding wire for ship crack arrest steel has the advantages of high strength, good low-temperature toughness, good crack resistance and high deposition rate, stable arc, less spatter, easy slag removal and beautiful weld formation, and can be suitable for welding crack arrest steel in the core structure of ultra-large container ships.

[0026] The first aspect of the present invention provides a flux-cored welding wire for ship crack arrest steel, the flux-cored welding wire comprising a steel strip and a flux core filled in the steel strip, the flux core comprising the following components in parts by weight: 10 to 15 parts of rutile, 5 to 6 parts of quartz, 2 to 4 parts of ferrotitanium, 20 to 40 parts of sodium fluoride, 20 to 40 parts of potassium feldspar, 6 to 18 parts of manganese silicon alloy, 4 to 8 parts of low-carbon ferromanganese, 1.5 to 2.5 parts of magnesium powder, 1.5 to 2 parts of rare earth ferrosilicon, 0.2 to 0.4 parts of ferroboron, 1 to 2 parts of metallic nickel, and 1.5 to 6 parts of iron powder.

[0027] Among them, rutile is a slag-forming agent and the main component of slag, which can significantly reduce the viscosity and surface tension of slag. The main component of rutile is titanium dioxide (TiO 2 ), when there is more titanium dioxide in the slag, "short slag" is formed, which is beneficial to the formation of the weld. The weight proportion of rutile in the flux core of the present invention is 10 to 15 parts, for example, it can be 10 parts, 12 parts, 14 parts or 15 parts.

[0028] Quartz is used as a slag-making agent, and its main component is silicon dioxide (SiO 2 ), the silicon dioxide content increases, the weld surface is brighter, the slag color is darker, which is beneficial to the slag removal of the weld, but excessive addition of silicon dioxide will affect the low-temperature toughness of the weld. The weight proportion of quartz in the flux core of the present invention is 5 to 6 parts, for example, 5 parts, 5.5 parts or 6 parts.

[0029] Ferrotitanium can be a transition alloy element to the weld metal. Titanium is a strong oxidant, which can promote the formation of acicular ferrite, refine grains, increase grain boundary area, improve the mechanical properties of the material, and has a good slag-forming effect. Titanium can also form stable carbides, so adding titanium can also prevent intergranular corrosion. The weight proportion of ferrotitanium in the flux core of the present invention is 2 to 4 parts, for example, 2 parts, 3 parts or 4 parts.

[0030] Sodium fluoride mainly plays a role in slag formation. In the welding process, the sodium (Na) element can play a role in deoxidation and desulfurization, and the fluorine (F) element can play a role in dehydrogenation and can also play a role in purifying the deposited metal. The weight proportion of sodium fluoride in the flux core of the present invention is 20 to 40 parts, for example, 20 parts, 30 parts, 35 parts or 40 parts.

[0031] The main component of potassium feldspar is K 2 O.Al 2 O 3 6SiO 2 , where K 2 O can provide K with low ionization potential + , enhance arc stability, SiO 2 It can reduce the basicity and surface tension of the slag, refine the molten droplets, and promote the transition of rare earth elements. The weight proportion of potassium feldspar in the core of the present invention is 20 to 40 parts, for example, 20 parts, 25 parts, 35 parts or 40 parts.

[0032] The manganese (Mn) element in the manganese silicon alloy is an important deoxidizer. At the same time, Mn can improve the strength of the body when it is solid-dissolved in the matrix, and has the effect of solid-solution strengthening. Under the action of an appropriate amount of C, acicular ferrite is formed, thereby improving the strength and low-temperature impact toughness of the weld metal. The weight proportion of the manganese silicon alloy in the flux core of the present invention is 6 to 18 parts, for example, 6 parts, 10 parts, 15 parts or 18 parts.

[0033] Low carbon ferromanganese is mainly used as a deoxidizer, alloying agent and desulfurizer. Excessive use of low carbon ferromanganese will increase splashing. The weight proportion of low carbon ferromanganese in the core of the present invention is 4 to 8 parts, for example, 4 parts, 5 parts, 7 parts or 8 parts.

[0034] Magnesium powder is mainly used as a deoxidizer and desulfurizer. Magnesium powder can effectively reduce the impurity content of the deposited metal, and its oxidation product MgO can increase the slag basicity and improve the low-temperature toughness of the deposited metal. The weight proportion of magnesium powder in the flux core of the present invention is 1.5 to 2.5 parts, for example, 1.5 parts, 1.8 parts, 2.1 parts or 2.5 parts.

[0035] The main component of rare earth ferrosilicon, silicon (Si), plays a major role in deoxidation during welding, and the rare earth element cerium (Ce) plays a role in desulfurization and deoxidation. In addition, a trace amount of Ce can significantly refine the grains and improve the low-temperature impact toughness of the weld metal. The weight proportion of rare earth ferrosilicon in the flux core of the present invention is 1.5 to 2 parts, for example, 1.5 parts, 1.8 parts or 2 parts.

[0036] Ferroboron is used as a transition alloy element to the weld metal. Boron (B) can inhibit the formation of proeutectoid ferrite at the grain boundary, refine the grains, increase the grain boundary area, and the appropriate addition of boron is beneficial to improving the strength and toughness of the weld. Adding a trace amount of boron can also reduce the phase transformation rate during cooling, thereby significantly improving the hardenability of steel. Boron can also improve the ductility of steel. The mass percentage of ferroboron in the flux core of the present invention is 0.2 to 0.4 parts, for example, it can be 0.2 parts, 0.3 parts or 0.4 parts, etc.

[0037] Metal nickel (Ni) is used as an alloying element for transition to weld metal. Nickel is a relatively stable alloying element. Adding Ni can refine the structure, promote the formation of acicular ferrite, increase the self-corrosion points of steel, thereby improving the stability of steel and significantly improving the low-temperature impact toughness. The weight percentage of metal nickel in the flux core of the present invention is 1 to 2 parts, for example, 1 part, 1.5 parts or 2 parts.

[0038] The iron powder can increase the weld metal, improve the deposition efficiency, improve the welding arc state and adjust the fluidity of the molten iron. The weight proportion of the iron powder in the flux core of the present invention is 1.5 to 6 parts, for example, 1.5 parts, 3 parts, 4 parts or 6 parts.

[0039] In some embodiments, the content of titanium dioxide in rutile is ≥ 95 wt %, the content of sulfur is ≤ 0.010 wt %, and the content of phosphorus is ≤ 0.010 wt %.

[0040] The silicon dioxide content in the quartz is ≥97wt%, the sulfur content is ≤0.040wt%, and the phosphorus content is ≤0.040wt%.

[0041] The content of silicon dioxide in potassium feldspar is 63-73wt%, the content of aluminum oxide is 15-22wt%, and the balance is potassium oxide and unavoidable impurities.

[0042] The purity of sodium fluoride is ≥98wt%, the purity of magnesium powder is ≥98%, the purity of iron powder is ≥99%, and the purity of metallic nickel is ≥99%.

[0043] The titanium iron uses 30# titanium iron, in which the titanium content is 25-35wt%, the phosphorus content is less than or equal to 0.02wt%, the sulfur content is less than or equal to 0.02wt%, and the balance is iron.

[0044] The manganese content in the manganese silicon alloy is 62-67wt%, the silicon content is 20-23wt%, and the balance is unavoidable impurities.

[0045] The manganese content in low carbon ferromanganese is ≥80wt%, the carbon content is ≤0.7wt%, and the balance is iron and unavoidable impurities;

[0046] The rare earth ferrosilicon uses a material with the grade of RESiFe-32Ce, in which the RE element content is 30-33wt%, Ce / RE≥46wt%, and the Si element content is ≤40wt%.

[0047] The ferroboron is selected from low-carbon ferroboron, for example, ferroboron with the grade of FeB22C0.05, wherein the boron content is 21-25wt%, the carbon content is ≤0.05wt%, and the aluminum content is ≤1.5wt%.

[0048] In one embodiment, the filling rate of the flux core in the flux-cored welding wire for marine crack arrest steel, that is, the filling amount of the flux core, accounts for 17-20% of the total weight of the flux core and the steel strip. For example, the filling rate of the flux core can be 17%, 18%, 19% or 20%.

[0049] Research has found that the particle size of each component in the flux core will also affect its welding effect. In one embodiment, the particle size of each component in the flux core is controlled at 60 to 80 meshes, such as 60 meshes, 70 meshes or 80 meshes. The above-mentioned particle size refers to the size of the raw material particles. The larger the mesh number, the finer the particles. In practical applications, the flux core is first configured according to the above-mentioned component ratio, and then the flux core is filled into the steel strip at a filling rate of 17 to 20%.

[0050] In one embodiment, the steel strip in the flux-cored welding wire is a carbon steel strip, such as a low-carbon steel strip, wherein the carbon content of the low-carbon steel strip is ≤0.04wt%, the manganese content is 0.1-0.3wt%, the silicon content is ≤0.05wt%, the phosphorus content is ≤0.0250wt%, the sulfur content is ≤0.020wt%, and the rest is iron.

[0051] In one embodiment, the diameter of the flux-cored welding wire is 1.2-1.6 mm, that is, when preparing the flux-cored welding wire, the steel strip wrapped with the flux core is drawn and reduced in diameter through a wire drawing die one by one, so that its diameter reaches 1.2-1.6 mm, for example, the diameter of the flux-cored welding wire can be 1.2 mm, 1.4 mm or 1.6 mm, etc. The diameter of the flux-cored welding wire can be set according to the specific requirements.

[0052] See also Figure 1 The present invention provides a method for preparing the above-mentioned flux-cored welding wire for ship crack arrest steel, comprising the following steps:

[0053] S1. Mix the various core components evenly to prepare the core;

[0054] S2, cutting the steel strip longitudinally and rolling it into a U-shaped groove;

[0055] S3, filling the drug core into the U-shaped groove;

[0056] S4. The steel strip filled with the flux core is closed-rolled, and the diameter is reduced to a preset diameter by drawing to obtain a flux-cored welding wire for ship crack arrest steel.

[0057] Among them, step S1 first weighs each component in the proportion of: 10-15 parts of rutile, 5-6 parts of quartz, 2-4 parts of ferrotitanium, 20-40 parts of sodium fluoride, 20-40 parts of potassium feldspar, 6-18 parts of manganese silicon alloy, 4-8 parts of low-carbon ferromanganese, 1.5-2.5 parts of magnesium powder, 1.5-2 parts of rare earth ferrosilicon, 0.2-0.4 parts of ferroboron, 1-2 parts of metallic nickel, and 1.5-6 parts of iron powder, and then mixes and stirs evenly. The purity requirements of each component in this step are as described above and will not be repeated here. The mixing and stirring method in this step is not limited, and any method that can mix the components evenly can be used. In one example, a rotary mixing pot is used, and the stirring time is continued for not less than 30 minutes until the components of the core are evenly mixed. In another example, a powder mixer can also be used for mixing, and so on.

[0058] Furthermore, before mixing the powders, the symmetrically taken components need to be dried to remove moisture from the powders.

[0059] In step S2, the steel strip is longitudinally cut into a suitable size and then cleaned by wrapping to remove impurities on the surface of the steel strip, and then the steel strip is rolled into a U-shaped groove. The steel strip used in the present invention is a carbon steel strip, such as a low-carbon steel strip, wherein the carbon content in the low-carbon steel strip is ≤0.04wt%, the manganese content is 0.1-0.3wt%, the silicon content is ≤0.05wt%, the phosphorus content is ≤0.0250wt%, the sulfur content is ≤0.020wt%, and the rest is iron. Furthermore, the size of the carbon steel strip: thickness × width is 1.0mm × 14mm.

[0060] In step S3, the filling rate of the drug core is 17% to 20%. For example, the filling rate of the drug core can be any value within the above range, such as 17%, 18%, 19% or 20%.

[0061] Step S4 is to use a wire drawing machine to draw and reduce the steel strip filled with the flux core to a preset specification. Lubricating powder can be used to increase its lubricity during the wire drawing process, for example, graphite lubricating powder can be used. The final diameter of the flux cored welding wire is 1.2 to 1.6 mm, for example, 1.2 mm, 1.4 mm or 1.6 mm.

[0062] The present invention also provides the application of flux-cored welding wire for marine crack arrest steel on ultra-large container ships. 2 Under the protection of mixed gas, the weld has no pores, good welding process performance, stable arc, less spatter, easy slag removal, beautiful weld formation, and its weld metal has good tensile strength, low temperature toughness and crack resistance. Therefore, this flux-cored wire for crack arrest steel for ships is suitable for welding crack arrest steel in the core structure of ultra-large container ships.

[0063] The present invention is described in detail below through some specific examples. The drugs used in the following examples can all be obtained through common commercial means.

[0064] Example 1

[0065] The flux-cored welding wire for crack arrest steel for ship use in this embodiment comprises a steel strip and a flux core filled in the steel strip, wherein the flux core comprises the following components in parts by weight: 10 parts of rutile, 5 parts of quartz, 2 parts of ferrotitanium, 35 parts of sodium fluoride, 40 parts of potassium feldspar, 10 parts of manganese silicon alloy, 8 parts of low-carbon ferromanganese, 1.5 parts of magnesium powder, 1.5 parts of rare earth ferrosilicon, 0.2 parts of ferroboron, 1 part of metal nickel, and 1.5 parts of iron powder. The steel strip is a 1.0 mm×14 mm low-carbon steel strip.

[0066] The preparation process is as follows: first, the low-carbon steel strip is rolled into a U-shaped groove, and then the evenly mixed flux core is filled into the U-shaped groove, and the filling rate of the flux core is 18%; then it is closed, reduced in diameter, drawn, and wound to obtain a welding wire with a diameter of 1.4 mm.

[0067] Example 2

[0068] The flux-cored welding wire for crack arrest steel for ships of this embodiment comprises a steel strip and a flux core filled in the steel strip, wherein the flux core comprises the following components by weight: 12 parts of rutile, 6 parts of quartz, 3 parts of ferrotitanium, 20 parts of sodium fluoride, 25 parts of potassium feldspar, 6 parts of manganese silicon alloy, 7 parts of low-carbon ferromanganese, 1.8 parts of magnesium powder, 1.5 parts of rare earth ferrosilicon, 0.3 parts of ferroboron, 1.5 parts of metal nickel, and 6 parts of iron powder. The steel strip is a 1.0mm×14mm low-carbon steel strip.

[0069] The preparation process is as follows: first, the low carbon steel strip is rolled into a U-shaped groove, and then the evenly mixed flux core is filled into the U-shaped groove, and the filling rate of the flux core is 19%; then it is closed, reduced in diameter, drawn, and wound to obtain a welding wire with a diameter of 1.6 mm.

[0070] Example 3

[0071] The flux-cored welding wire for crack arrest steel for ships of this embodiment comprises a steel strip and a flux core filled in the steel strip, wherein the flux core comprises the following components in parts by weight: 14 parts of rutile, 5.5 parts of quartz, 3 parts of ferrotitanium, 40 parts of sodium fluoride, 35 parts of potassium feldspar, 18 parts of manganese silicon alloy, 5 parts of low-carbon ferromanganese, 2.1 parts of magnesium powder, 1.8 parts of rare earth ferrosilicon, 0.3 parts of ferroboron, 2 parts of metal nickel, and 4 parts of iron powder. The steel strip is a 1.0mm×14mm low-carbon steel strip.

[0072] The preparation process is as follows: first, the low-carbon steel strip is rolled into a U-shaped groove, and then the evenly mixed flux core is filled into the U-shaped groove, and the filling rate of the flux core is 18%; then it is closed, reduced in diameter, drawn, and wound to obtain a welding wire with a diameter of 1.4 mm.

[0073] Example 4

[0074] The flux-cored welding wire for crack arrest steel for ships of this embodiment comprises a steel strip and a flux core filled in the steel strip, wherein the flux core comprises the following components in parts by weight: 15 parts of rutile, 6 parts of quartz, 4 parts of ferrotitanium, 30 parts of sodium fluoride, 20 parts of potassium feldspar, 15 parts of manganese silicon alloy, 4 parts of low-carbon ferromanganese, 2.5 parts of magnesium powder, 2 parts of rare earth ferrosilicon, 0.4 parts of ferroboron, 1.5 parts of metal nickel, and 3 parts of iron powder. The steel strip is a 1.0mm×14mm low-carbon steel strip.

[0075] The preparation process is as follows: first, roll the low-carbon steel strip into a U-shaped groove, then fill the U-shaped groove with a uniformly mixed flux core, and the filling rate of the flux core is 20%; then close, reduce the diameter, draw the wire, and take up the wire to obtain a welding wire with a diameter of 1.2 mm.

[0076] The contents of the components of the flux core in the flux cored welding wire for marine crack arrest steel of Examples 1 to 4 are shown in Table 1.

[0077] In order to further verify the effect of the present invention, the flux-cored welding wire for marine crack arrest steel of Examples 1-4 was used for all-position welding of high-strength crack arrest steel, and 80% Ar + 20% CO was used for welding. 2 Mixed gas, gas purity above 99.8%, then the chemical composition of weld metal and mechanical properties of weld metal are tested according to relevant standards and specifications in this field. The welding process performance is shown in Table 2, the chemical composition test results of weld metal are shown in Table 3, and the mechanical properties of weld metal are shown in Table 4.

[0078] Table 1 Core components of flux-cored welding wires of Examples 1 to 4

[0079]

[0080] Table 2: Welding process performance

[0081]

[0082] Table 3: Chemical composition test results of weld metal (Wt.%)

[0083]

[0084] Table 4: Mechanical properties of weld metal

[0085]

[0086] The test results of Examples 1 to 4 show that the flux-cored welding wire for marine crack arrest steel of the present invention can be used in 80% Ar + 20% CO 2 All-position welding is carried out under the protection of mixed gas, and the arc is stable during welding, with small spatter, good welding processability such as forming and slag removal, and the deposited metal has good tensile strength, low-temperature toughness and crack resistance.

[0087] The flux-cored welding wire for crack arrest steel for ships of the present invention uses the Mn-Si-Ti-B alloy system, and the microalloying effect of Ti-B and the purification effect of rare earth elements promote the formation of acicular ferrite to further improve the toughness of the weld, so that the weld metal has excellent impact toughness at low temperatures. The addition of rare earth elements can improve the high-temperature corrosion resistance and impact toughness of the weld metal; the addition of potassium feldspar and rutile can form a short slag effect, which is beneficial to the formation of the weld; this welding wire is used for the welding of crack arrest steel in the core structural parts of ultra-large container ships. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and use significance.

[0088] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A flux-cored welding wire for marine crack arrest steel, characterized in that: The invention comprises a steel strip and a core filled in the steel strip, wherein the core comprises the following components in parts by weight: 10 to 15 parts of rutile, 5 to 6 parts of quartz, 2 to 4 parts of ferrotitanium, 20 to 40 parts of sodium fluoride, 20 to 40 parts of potassium feldspar, 6 to 18 parts of manganese silicon alloy, 4 to 8 parts of low-carbon ferromanganese, 1.5 to 2.5 parts of magnesium powder, 1.5 to 2 parts of rare earth ferrosilicon, 0.2 to 0.4 parts of ferroboron, 1 to 2 parts of metallic nickel and 1.5 to 6 parts of iron powder.

2. The flux-cored welding wire for ship crack arrest steel according to claim 1, characterized in that: The ferrotitanium is 30# ferrotitanium; the manganese content in the manganese silicon alloy is 62-67wt%, and the silicon content is 20-23wt%; the manganese content in the low-carbon ferromanganese is ≥80wt%, and the carbon content is ≤0.7wt%; the rare earth ferrosilicon adopts rare earth ferrosilicon with the grade of RESiFe-32Ce; the ferroboron adopts ferroboron with the grade of FeB22C0.

05.

3. The flux-cored welding wire for ship crack arrest steel according to claim 1, characterized in that: The titanium dioxide content in the rutile is ≥95wt%, the sulfur content is ≤0.010wt%, and the phosphorus content is ≤0.010wt%; the silicon dioxide content in the quartz is ≥97wt%, the sulfur content is ≤0.040wt%, and the phosphorus content is ≤0.040wt%; the silicon dioxide content in the potassium feldspar is 63-73wt%, and the aluminum oxide content is 15-22wt%.

4. The flux-cored welding wire for ship crack arrest steel according to claim 1, characterized in that: The purity of the sodium fluoride is ≥98%; the purity of the magnesium powder is ≥98%; the purity of the iron powder is ≥99%; and the purity of the metallic nickel is ≥99%.

5. The flux-cored welding wire for ship crack arrest steel according to claim 1, characterized in that: The particle size of each component in the drug core is 60-80 meshes.

6. The flux-cored welding wire for ship crack arrest steel according to claim 1, characterized in that: The filling amount of the flux core accounts for 17% to 20% of the total weight of the flux cored welding wire.

7. The flux-cored welding wire for ship crack arrest steel according to claim 1, characterized in that: The steel strip is a carbon steel strip.

8. The flux-cored welding wire for ship crack arrest steel according to claim 1, characterized in that: The diameter of the flux-cored welding wire is 1.2-1.6 mm.

9. A method for preparing a flux-cored welding wire for marine crack arrest steel according to any one of claims 1 to 8, characterized in that: The following steps are involved: Mixing the various drug core components uniformly to prepare the drug core; The steel strip is cut longitudinally and then rolled into a U-shaped groove; Filling the drug core into the U-shaped groove; The steel strip filled with the flux core is closed rolled, and is drawn and reduced to a preset diameter to obtain a flux cored welding wire for marine crack arrest steel.

10. An application of a flux-cored welding wire for marine crack arrest steel according to any one of claims 1 to 8, characterized in that: The flux-cored welding wire for crack arrest steel for ships is used for welding crack arrest steel of the core structure of super-large container ships.

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