Marine steel q690e matching flux-cored wire

Abstract

The application discloses a ship steel Q690E matching flux-cored wire. The application has good welding process by reasonably designing the proportion of various powders in the formula, is suitable for all-position welding, has beautiful weld forming and easy deslagging, can be applied to the welding of ship steel Q690E base metal, is suitable for automatic welding and semi-automatic welding, and has no obvious difference from conventional flux-cored wire in welding process, and has strong applicability. The mechanical properties and crack resistance of the weld metal after welding can meet the requirements of China Classification Society and American Bureau of Shipping.

Description

TECHNICAL FIELD

[0001] The present application relates to the welding technical field of ship steel, and in particular to a flux-cored wire matched with ship steel Q690E. BACKGROUND

[0002] With the continuous improvement of the strength level of domestic shipbuilding steel, Q690 grade steel plates have been widely used in shipbuilding, especially in the manufacture of floating cranes and warships.

[0003] Q690E steel plates are widely used because of their high strength, high reliability and good low-temperature toughness at -40 DEG C. At present, the flux-cored wires matched with ship steel Q690E can be relatively less for all-position welding, and the market is mainly supplied with basic slag type flux-cored wires. The basic welding wire has good low-temperature impact toughness and crack resistance.

[0004] However, the basic welding wire itself has many process defects, such as uncentralized arc in the welding process, large spatter, and difficult to form in vertical welding. It is generally only suitable for flat welding and flat angle welding. However, the welding seam in the manufacturing process of ships involves all-position welding. The basic flux-cored wire matched with ship steel Q690E is difficult to meet the requirements of all-position welding. The acid flux-cored wire matched with Q690E ship steel with rutile slag system also generally has the problem of instability of the mechanical properties of the welded joint. The main problems are the instability of the low-temperature impact toughness of the weld metal and the general problem of crack resistance.

[0005] To solve the above problems, a flux-cored wire matched with Q690E ship steel for all-position welding is developed in this paper, which can meet the requirements of China Classification Society and American Classification Society in terms of mechanical properties and crack resistance. SUMMARY

[0006] In order to overcome the above-mentioned defects of the prior art, the purpose of the present application is to provide a flux-cored wire matched with ship steel Q690E. The flux-cored wire of the present application can be used for all-position welding, and the mechanical properties and crack resistance of the weld metal after welding can meet the requirements of China Classification Society and American Classification Society.

[0007] In order to achieve the purpose of the present application, the technical scheme adopted is:

[0008] A flux-cored wire matched with ship steel Q690E, the flux-cored wire comprises, by weight percentage:

[0009] 6-10% of reduced ilmenite;

[0010] 15-20% of rutile;

[0011] 2-6% of alumina;

[0012] 2-4% of potassium titanate;

[0013] Zircon sand 0.5-3%;

[0014] Atomized spherical magnesium powder 0.5-2%;

[0015] Aluminum-magnesium alloy 1.5-4%;

[0016] Titanium-iron 0.1-1%;

[0017] Molybdenum powder 1-3%;

[0018] Molybdenum-iron 1-3%;

[0019] Nickel powder 8-12%;

[0020] Metallic manganese 5-9%;

[0021] High-carbon ferromanganese 2-5%;

[0022] Manganese-silicon alloy 2-8%;

[0023] Silicon-iron 2-8%;

[0024] Sodium fluosilicate 2-7%;

[0025] Potassium fluosilicate 2-7%;

[0026] Boron-iron powder 0.1-0.4%;

[0027] Glass powder 1-3%,

[0028] Rare earth silicon-iron 0.5-2%, the balance being iron powder, the sum of the above components being 100%.

[0029] In a preferred embodiment of the present application, the silicon-iron is 45# silicon-iron.

[0030] In a preferred embodiment of the present application, the glass powder is obtained by grinding SiO2, Al2O3, CaO, MgO, B2O3, Na2O in proportions, such as:

[0031] SiO2: 60%-75%;

[0032] Al2O3: 0.5%-3%;

[0033] CaO: 6%-10%;

[0034] MgO: 3%-20%;

[0035] B2O3: 1%-3%;

[0036] Na2O≥14%.

[0037] In a preferred embodiment of the present application, the rutile is a rutile calcined at a temperature of 750-900 DEG C to a moisture content of not more than 0.01%.

[0038] In a preferred embodiment of the present application, the zircon sand is a zircon sand calcined at a temperature of 750-900 DEG C to a moisture content of not more than 0.01%.

[0039] In a preferred embodiment of the present application, the atomized spherical magnesium powder has a particle size range of 80-160 mesh.

[0040] In a preferred embodiment of the present application, the nickel powder has a particle size range of 100-200 mesh.

[0041] In a preferred embodiment of the present application, the molybdenum powder has a particle size range of 100-200 mesh.

[0042] The present application has the following beneficial effects:

[0043] 1. The present application has good welding process properties by reasonably designing the proportions of various powders in the formula, is suitable for all-position welding, has a beautiful weld appearance and easy deslagging, can be applied to the welding of ship Q690E steel base material, is suitable for automatic and semi-automatic welding, and has no obvious difference from conventional flux-cored wires in welding process, and has strong applicability.

[0044] 2. The welding wire of the present application uses a rutile slag system with high alkalinity, and the welded ship Q690E steel has excellent mechanical properties, i.e., tensile strength Rm; 770-940 (MPa), yield strength ReL; ≥690 (MPa), elongation A ≥17%, -40 DEG C low temperature impact AKV ≥69 (J), and diffusion hydrogen content ≤5 mL / 100g, which meets the requirements of China Classification Society and American Classification Society.

[0045] 3. The present application can realize the weld metal H5 below by adding various fluorides, rare earths and reduced ilmenite under the welding metallurgical action, realizes the diffusion hydrogen H5 below in the conventional flux-cored wire manufacturing process, greatly simplifies the H5 manufacturing process, and greatly improves the crack resistance of the weld metal.

[0046] 4. The molten slag is analyzed by using a wavelength dispersion X-ray spectrometer, and the molten slag alkalinity B2 is calculated by using a molten slag alkalinity calculation formula (wherein xk is the mass fraction of the kth oxide in the molten slag; ak is the alkalinity coefficient of the kth oxide in the molten slag) to be greater than -1. DETAILED DESCRIPTION

[0047] The present application will be further described below in combination with specific embodiments.

[0048] The working principle of the present application is that:

[0049] Rutile: In the welding process, mainly play a role in slag, arc stability, rutile hot slagging, arc stability, calm, directional welding pool, good weld forming.

[0050] Glass powder: Glass powder is formed by glass manufacturing process, and grinding to 80 mesh, wherein SiO2: 60%-75%, Al2O3: 0.5%-3%, CaO: 6%-10%, MgO: 3%-20%, B2O3: 1%-3%, Na20≥14%. The addition of glass powder can be used as a slag former, not only can adjust the viscosity of the slag, improve the welding process performance, but also can adjust the basicity of the slag, can improve the weld metal crack resistance.

[0051] F in sodium fluorosilicate, potassium fluorosilicate and cerium fluoride metal fluoride can form HF gas with H+ in the molten pool, which has good dehydrogenation effect and dilution effect on the molten pool, and the addition of ilmenite can not only form slag, but also form strong oxygen partial pressure in the welding droplet formation process, which can fully protect the droplet metal. TiO2 not only can form slag, protect the molten pool, but also has the functions of arc stabilization and nucleation, which can improve the physical properties of the slag, change the long slag into short slag, make the molten slag change quickly with temperature, make the weld forming well, the weld forming is fine and bright, and the de-slaging property is improved.

[0052] The added magnesium powder is atomized spherical magnesium powder, which is formed by various processing procedures under the protection of inert gas by centrifugal atomization technology. Compared with the existing magnesium powder for flux-cored wire, it has large bulk density, good fluidity, small specific surface area, lower impurity content, is easier to be uniform in the flux, has good deoxidation effect, stable mechanical properties of weld metal, and the formed MgO slag greatly improves the basicity of the weld metal, ensuring the crack resistance of the weld metal.

[0053] Potassium titanate has K+ as a low ionization potential ion, which can further protect the arc, making it have small spatter, concentrated arc, good operability, and excellent welding process.

[0054] Nickel powder: The melting point of nickel powder is 1452℃, its affinity with oxygen is smaller than that of iron, it is not easy to oxidize during welding, and the excess coefficient is high. Nickel powder in the weld mainly plays a role in improving strength and toughness, especially low temperature toughness, which increases with the increase of nickel content within a certain content range.

[0055] Titanium iron; Ti has a strong binding force with oxygen, so that the Ti in the weld is dispersed in the form of tiny oxide particles (TiO) in the weld, promoting the refinement of the weld metal. On the other hand, Ti protects B from oxidation in the weld, so B can be segregated as an atomic state at the grain boundary. These B atoms gathered at the γ grain boundary reduce the grain boundary energy, inhibit the nucleation and growth of pro-eutectoid ferrite, and thus promote the formation of acicular ferrite, improving the toughness of the weld structure.

[0056] Molybdenum powder and molybdenum iron; The addition of molybdenum powder and molybdenum iron is mainly to infiltrate the alloy, which is basically not oxidized during the welding process, and the transition coefficient reaches more than 90%. A certain amount of molybdenum can refine the grains, improve the strength and low-temperature toughness of the weld, and prevent crack sensitivity. After repeated test tests, it is found that the addition of molybdenum powder and molybdenum iron in a mixed form makes it easier for the metal Mo to be more evenly distributed in the weld.

[0057] Metallic manganese, silicon-manganese alloy, high-carbon ferromanganese, which mainly plays a role in deoxidation, desulfurization and improving the strength of the weld in welding metallurgy. When the Mn / Si ratio is within a certain range, the low-temperature impact toughness can be greatly improved. In low-carbon steel, when the Mn / S ratio is 15:1, the hot crack sensitivity is small. The carbon content in high-carbon ferromanganese is 6.5-7%, which can transition a certain amount of C to the weld metal, greatly improving the tensile strength and yield strength of the weld.

[0058] Rare earth ferrosilicon; The silicon iron in rare earth ferrosilicon can act as a deoxidizer and participate in welding metallurgy. Silicon melts into the weld metal to improve the strength of the weld. The appropriate amount of rare earth makes the banded manganese sulfide inclusions in the weld gradually metamorphose into spherical dispersed inclusions with a size of less than 2 μm. The organization of the steel is refined, and under the action of solid-solution rare earth, the morphology of the weld fracture can be effectively improved, and the low-temperature impact toughness of the weld can be improved.

[0059] The addition of 2-8% ferrosilicon and 0.5-2% rare earth ferrosilicon not only utilizes the purification effect of rare earth in the weld metal, but also ensures sufficient deoxidation in the weld metal with appropriate silicon content, and the tensile strength and yield strength of the weld metal can fully meet the relevant ship classification society standard for flux-cored wire for steel plate Q690E.

[0060] Examples 1-3: Preparation of flux-cored wire matched with ship steel plate Q690E.

[0061] 1. The method in Examples 1-3 is:

[0062] Rutile, zircon sand, and the like are calcined at 750-900 DEG C in a rotary calcining furnace to remove the crystal water and absorbed water in the minerals. The rotary calcining furnace has the advantages that the box-type furnace does not have. At 750-900 DEG C, the furnace body rotates continuously at a set frequency, and the calcined material is heated uniformly, with very low moisture content. For example, the moisture content of rutile and other minerals can be as low as 0.01% or even lower, which can ensure that the H content of the mineral powder in the flux-cored wire is very low, thereby ensuring the low hydrogen content of the present application. Potassium titanate and reduced ilmenite are baked at 350-500 DEG C in a box-type high-temperature furnace to remove moisture.

[0063] Table 1 is the core ratio in Examples 1-3:

[0064]

[0065]

[0066] The powder is prepared according to the ratio in Table 1, stirred in a V-type mixer, and baked at high temperature. The HS1 carbon steel strip (chemical composition shown in Table 2) with a specification of 1.0x14 mm is used. The powder is loaded into the steel strip at a filling rate of 16%-17% through a forming process, and the wire is drawn to a specification of 1.2 mm through a fine drawing process.

[0067] Table 2 shows the content of each chemical component in the HS1 carbon steel strip:

[0068] Element C Mn Si S P Content (%) 0.02-0.04 0.15-0.35 ≤0.035 ≤0.005 ≤0.005

[0069] 2. The welding test plate is welded according to the requirements of the China Classification Society (CCS) and the American Bureau of Shipping (ABS). The chemical composition and mechanical properties of the deposited metal are shown in Tables 3 and 4.

[0070] Table 3 shows the content of each chemical component in Examples 1-3:

[0071]

[0072] Table 4 shows the mechanical properties of Examples 1-3:

[0073] Rm (MPa) ReL (MPa) A(％) AKV (J) (-40°C) CCS 770-940 ≥690 ≥17 ≥69 ABS 770-940 ≥690 ≥17 ≥69 Example 1 790 710 21 82 75 85 Example 2 812 730 19.2 87 83 90 Example 3 804 712 19.5 85 88 83

[0074] As shown in Table 4, the mechanical properties of Examples 1-3 meet the requirements.

[0075] 3. The slag after welding of Examples 1-3 is analyzed using a wavelength dispersive X-ray spectrometer. The slag oxide content is shown in Table 5.

[0076] Table 5 shows the slag oxide content:

[0077]

[0078]

[0079] From Table 5, the slag basicity B2 of Examples 1-3 is greater than -1. Since Examples 1-3 use the rutile slag system, i.e. the acid slag system, the slag basicity is less than 0, which is not obviously different from the welding process of the conventional rutile slag system, is suitable for all-position welding, and B2>-1 indicates that the acid oxide in the slag is significantly reduced compared with the conventional rutile slag system, and the basic oxide is relatively high. The molten pool under this slag type can better remove S and P, and has obvious benefits for the low-temperature toughness and crack resistance of the weld metal.

[0080] 4. ISO 3690 thermal diffusion hydrogen test and inclined Y crack restraint test were carried out on Examples 1-3, and the specific test results are shown in Tables 6 and 7.

[0081] Table 6: Results of ISO 3690 thermal diffusion hydrogen test

[0082] ISO 3690 thermal conductivity method Example 1 Example 2 Example 3 Diffusible hydrogen content ml / 100g 3.7 4.3 4.0

[0083] From Table 6, the diffusion hydrogen content ml / 100g of Examples 1-3 is all less than or equal to 5 mL / 100g.

[0084] Table 7: Results of inclined Y crack restraint test (test method adopts GB / T4675.1)

[0085]

[0086]

[0087] From Table 7, the crack rate of Examples 1-3 is 0 at the surface, end surface and root.

[0088] 5. Butt welds of Examples 1-3 were subjected to bending test (according to CCS, ABS ship classification society ship rules), and the bending results are shown in Table 8.

[0089] Table 8: Results of bending test

[0090]

[0091] And for the conventional rutile slag system Q690 matching flux-cored wire, the flux-cored wire ratio and test results are as shown in Tables 9 and 10.

[0092]

[0093]

[0094] Table 10: Results of bending test

[0095]

[0096] From Table 10, it can be seen that the bending tests of Comparative Examples 1 and 2 were not satisfactory.

[0097] The above shows and describes the basic principles and main features of the application and the advantages of the application.

[0098] Those skilled in the art should understand that the application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the application. Without departing from the spirit and scope of the application, various changes and improvements can be made to the application, and these changes and improvements all fall within the scope of the claimed application. The scope of the application is defined by the appended claims and their equivalents.

Claims

1. A flux-cored wire for matching with a marine steel Q690E, characterized in that, The flux-cored wire comprises, by weight percentage: 6-10% of reduced ilmenite; 15-20% of rutile; 2-6% of alumina; 2-4% of potassium titanate; 0.5-3% of zircon sand; 0.5-2% of atomized spherical magnesium powder; 1.5-4% of aluminum-magnesium alloy; 0.1-1% of ferrotitanium; 1-3% of molybdenum powder; 1-3% of ferromolybdenum; 8-12% of nickel powder; 5-9% of metallic manganese; 2-5% of high-carbon ferromanganese; 2-8% of manganese-silicon alloy; 2-8% of ferrosilicon; 2-7% of sodium fluorosilicate; 2-7% of potassium fluorosilicate; 0.1-0.4% of ferroboron powder; 1-3% of glass powder, 0.5-2% of rare earth ferrosilicon, and the balance being iron powder, the sum of the above components being 100%.

2. The flux-cored wire for matching the marine steel Q690E according to claim 1, characterized in that, The ferrosilicon is 45# ferrosilicon.

3. The flux-cored wire for matching the marine steel Q690E according to claim 1, characterized in that, The glass powder is prepared by grinding SiO2, Al2O3, CaO, MgO, B2O3 and Na2O in a proportion, for example: SiO2: 60%-75%; Al2O3: 0.5%-3%; CaO: 6%-10%; MgO: 3%-20%; B2O3: 1%-3%; Na2O≥14%.

4. The flux-cored wire for matching the marine steel Q690E according to claim 1, characterized in that, The rutile is rutile calcined at a temperature of 750-900℃ until the moisture content is not more than 0.01%.

5. The flux-cored welding wire for shipbuilding steel Q690E according to claim 1, characterized in that, The zircon sand is zircon sand calcined at a temperature of 750-900℃ until the moisture content is not more than 0.01%.

6. The flux-cored welding wire for the marine steel Q690E according to claim 1, characterized in that, The atomized spherical magnesium powder has a particle size range of 80-160 mesh.

7. The flux-cored welding wire for the marine steel Q690E according to claim 1, characterized in that, The nickel powder has a particle size range of 100-200 mesh.

8. The flux-cored welding wire for the marine steel Q690E according to claim 1, characterized in that, The molybdenum powder has a particle size range of 100-200 mesh.

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