High fracture toughness titanium flux cored wire for offshore engineering

Abstract

The application provides a high fracture toughness titanium type flux-cored wire for ocean engineering, wherein the flux-cored wire comprises non-metallic flux powder and metallic flux powder. The application optimizes the deoxidizer component in the formula of the flux-cored wire, establishes the formula of the new titanium type flux-cored wire for ocean engineering, and effectively improves the low-temperature impact toughness and fracture toughness of the welded joint while meeting the use of ocean engineering.

Description

Technical Field

[0001] This invention belongs to the field of welding materials, and in particular relates to a high fracture toughness titanium-type flux-cored welding wire for marine engineering. Background Technology

[0002] With my country's economic development, social progress, and improved living standards, the demand for oil and natural gas is increasing. Given my country's abundant marine resources, the exploitation of offshore oil and gas resources is an inevitable trend. Oil and gas platforms are essential equipment units for offshore oil and gas extraction, mainly composed of jacket structures and superstructure modules.

[0003] Titanium-cored flux-cored wire gas shielded welding (FCAW) is characterized by high welding efficiency, good welding process, and ease of operation. Flux-cored wire accounts for approximately 70% of the consumption of various welding materials on offshore platforms, making FCAW the most important method for welding steel structures on offshore platforms.

[0004] The steel plates of marine platform structural components are thick and the service conditions are harsh. Developing a titanium-type flux-cored welding wire with high fracture toughness for marine engineering is of great significance to the safety and reliability of marine platform construction and use in my country. Summary of the Invention

[0005] In view of this, the present invention aims to overcome the defects in the prior art and proposes a high fracture toughness titanium-type flux-cored welding wire for marine engineering.

[0006] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0007] A high fracture toughness titanium-cored welding wire for marine engineering, wherein the welding wire core comprises non-metallic powder and metallic powder;

[0008] The non-metallic powder comprises the following components in parts by weight: 36 to 42 parts titanium dioxide powder, 2 to 5 parts zirconium oxide powder, 2 to 4 parts quartz, 1 to 2 parts potassium fluorosilicate, 1 to 2 parts sodium fluoroaluminate, 3 to 6 parts potassium sodium arc stabilizer, and 1 to 3 parts manganese monoxide.

[0009] The metallic powder comprises the following components in parts by weight: 12 to 16 parts silicon-manganese alloy, 4 to 6 parts metallic manganese powder, 2 to 5 parts atomized magnesium powder, 10 to 14 parts nickel powder, 2 to 4 parts titanium-boron alloy, and 3 to 12 parts iron powder.

[0010] Preferably, the flux core of the welding wire accounts for 12% to 14% of the total mass of the welding wire.

[0011] Preferably, the mass fraction of TiO2 in the titanium dioxide powder is ≥97%.

[0012] Preferably, the zirconium oxide powder contains ≥98% ZrO2 by mass.

[0013] Preferably, the mass fraction of Ni in the nickel powder is ≥99%.

[0014] Preferably, the flux-cored welding wire has a tensile strength of 550-720 MPa, a yield strength of ≥460 MPa, an elongation of ≥20%, an impact toughness of ≥60 J at -60℃, and a fracture toughness index of the welded joint: crack tip expansion displacement CTOD at -20℃ ≥0.3 mm.

[0015] This invention also provides a method for preparing the above-mentioned high fracture toughness titanium-type flux-cored welding wire for marine engineering, comprising the following steps:

[0016] 1) Prepare non-metallic and metallic medicinal powders in proportion, and bake the non-metallic and metallic medicinal powders.

[0017] 2) Mix the baked non-metallic and metallic powders together and stir.

[0018] 3) Cut the steel strip;

[0019] 4) The mixed non-metallic and metallic powders are fed together with the steel strip to the forming machine for rolling and drawing.

[0020] 5) Vacuum package the finished welding wire.

[0021] In the flux core of the welding wire of this invention:

[0022] Manganese monoxide: It has excellent deoxidation ability. When used in conjunction with magnesium powder that has been deoxidized in the early stage, it can effectively reduce oxide inclusions in the weld metal and improve impact toughness, low-temperature toughness and fracture toughness of the welded joint.

[0023] Atomized magnesium powder: It is a major deoxidizer and desulfurizer, which can effectively reduce the impurity content of the deposited metal. The oxidation product MgO can increase the basicity of the slag and improve the low-temperature toughness of the deposited metal.

[0024] Nickel powder: Nickel can lower the ductile-brittle transition temperature of weld metal. Under certain conditions, with the increase of nickel content, the strength increases to some extent, and the low-temperature impact toughness is significantly improved. Nickel also has high resistance to acid and alkali corrosion and advantages such as rust prevention and heat resistance at high temperatures. Increasing the nickel content significantly increases the overall weather resistance index, effectively improving the corrosion resistance of steel plates. However, excessive nickel content will increase the tendency of the weld metal to hot crack. Ni is a relatively stable alloying element; adding Ni can increase the self-corrosion sites in steel, thereby improving the stability of the steel.

[0025] Silicon-manganese alloy: It is a major deoxidizer and alloying agent, which can reduce the oxygen content of the weld metal and improve its strength. When its addition is less than 5%, deoxidation becomes poor and impact toughness deteriorates; when its addition exceeds 20%, the strength is too high and the impact toughness decreases.

[0026] Manganese metal powder is a major deoxidizer, desulfurizer, and alloying agent. It can be used in conjunction with silicon-manganese alloy for deoxidation and can effectively control the sulfur content of impurities in the deposited metal, improve the strength of the weld metal, reduce the surface tension of molten iron, and improve the weld bead formation.

[0027] In titanium-boron alloys: Titanium is a strong oxidizing agent. It promotes the formation of acicular ferrite, refines grains, increases grain boundary area, and improves the mechanical properties of the material. It also has a good slag-forming effect. Titanium can also form stable carbides, preventing the precipitation of Cr-rich carbides at grain boundaries; therefore, the addition of titanium can also prevent intergranular corrosion.

[0028] In titanium-boron alloys, boron can suppress the formation of proeutectoid ferrite at grain boundaries, refine grains, increase grain boundary area, and improve the strength and toughness of welds. However, low-temperature impact performance first increases and then decreases with increasing boron mass fraction. Adding trace amounts of boron can also reduce the phase transformation rate during cooling, thereby significantly improving the hardenability of the steel. Boron can also improve the ductility of the steel.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] This invention innovatively optimizes the deoxidizer component in the formulation of flux-cored welding wire, establishing a new formulation for titanium-type flux-cored welding wire for marine engineering. While meeting the requirements of marine construction, it effectively improves the low-temperature impact toughness and fracture toughness of the welded joint, and is particularly suitable for welding EH36-Z35 steel plates for marine platform structures. Detailed Implementation

[0031] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0032] The invention will be described in detail below with reference to specific embodiments.

[0033] The flux-cored welding wires used in the following examples and comparative examples were all prepared using the following process:

[0034] 1) Prepare each powder according to the proportion and bake it; 2) Mix and stir the baked powder; 3) Cut the steel strip; 4) Send the mixed powder and steel strip to the forming machine for rolling and drawing; 5) Vacuum package the finished welding wire.

[0035] Example 1

[0036] A high fracture toughness titanium-cored welding wire for marine engineering, the welding wire having a diameter of 1.2 mm, wherein the flux core comprises the following components in parts by weight: 36 parts titanium dioxide, 5 parts zirconium oxide, 2 parts quartz, 2 parts potassium fluorosilicate, 1 part sodium fluoroaluminate, 3 parts potassium titanate, 3 parts sodium titanate, 1 part manganese monoxide, 12 parts silicon-manganese alloy, 6 parts metallic manganese powder, 5 parts atomized magnesium powder, 10 parts nickel powder, 2 parts titanium-boron alloy, and 12 parts iron powder.

[0037] The flux core accounts for 14% of the total weight of the welding wire.

[0038] Chemical composition of flux-cored wire deposited metal:

[0039] Testing items C S Mn Si P Ni Ti B Example 1 0.038 0.006 1.57 0.28 0.009 1.45 0.046 0.0029

[0040] Mechanical properties of flux-cored wire deposited metal:

[0041] Testing items Tensile strength (MPa) Impact absorption energy (-60℃) (J) CTOD (-20℃) (mm) Example 1 622 106 0.471

[0042] Example 2

[0043] A high fracture toughness titanium-cored welding wire for marine engineering, the welding wire having a diameter of 1.2 mm, wherein the flux core comprises the following components in parts by weight: 39 parts titanium dioxide, 3 parts zirconium oxide, 3.5 parts quartz, 1.5 parts potassium fluorosilicate, 1.5 parts sodium fluoroaluminate, 2.5 parts potassium titanate, 2 parts sodium titanate, 2 parts manganese monoxide, 14 parts silicon-manganese alloy, 5 parts metallic manganese powder, 3 parts atomized magnesium powder, 12 parts nickel powder, 3 parts titanium-boron alloy, and 8 parts iron powder.

[0044] The flux core accounts for 13% of the total weight of the welding wire.

[0045] Chemical composition of flux-cored wire deposited metal:

[0046] Testing items C S Mn Si P Ni Ti B Example 2 0.040 0.005 1.53 0.31 0.008 1.53 0.052 0.0027

[0047] Mechanical properties of flux-cored wire deposited metal:

[0048] Testing items Tensile strength (MPa) Impact absorption energy (-60℃) (J) CTOD (-20℃) (mm) Example 2 615 125 0.489

[0049] Example 3

[0050] A high fracture toughness titanium-cored welding wire for marine engineering, the welding wire having a diameter of 1.2 mm, wherein the flux core comprises the following components in parts by weight: 42 parts titanium dioxide, 2 parts zirconium oxide, 4 parts quartz, 1 part potassium fluorosilicate, 2 parts sodium fluoroaluminate, 2 parts potassium titanate, 1 part sodium titanate, 3 parts manganese monoxide, 16 parts silicon-manganese alloy, 4 parts metallic manganese powder, 2 parts atomized magnesium powder, 14 parts nickel powder, 4 parts titanium-boron alloy, and 3 parts iron powder.

[0051] The flux core accounts for 14% of the total weight of the welding wire.

[0052] Chemical composition of flux-cored wire deposited metal:

[0053] Testing items C S Mn Si P Ni Ti B Example 3 0.039 0.007 1.50 0.32 0.008 1.57 0.048 0.0029

[0054] Mechanical properties of flux-cored wire deposited metal:

[0055] Testing items Tensile strength (MPa) Impact absorption energy (-60℃) (J) CTOD (-20℃) (mm) Example 3 608 112 0.516

[0056] Example 4

[0057] A high fracture toughness titanium-cored welding wire for marine engineering, the welding wire having a diameter of 1.2 mm, wherein the flux core comprises the following components in parts by weight: 40 parts titanium dioxide, 3 parts zirconium oxide, 3.5 parts quartz, 1.5 parts potassium fluorosilicate, 1.5 parts sodium fluoroaluminate, 2.5 parts potassium titanate, 2 parts sodium titanate, 3 parts manganese monoxide, 14 parts silicon-manganese alloy, 5 parts metallic manganese powder, 3 parts atomized magnesium powder, 12 parts nickel powder, 3 parts titanium-boron alloy, and 6 parts iron powder.

[0058] The flux core accounts for 13% of the total weight of the welding wire.

[0059] Chemical composition of flux-cored wire deposited metal:

[0060] Testing items C S Mn Si P Ni Ti B Comparative Example 2 0.039 0.006 1.52 0.30 0.009 1.56 0.050 0.0029

[0061] Mechanical properties of flux-cored wire deposited metal:

[0062] Testing items Tensile strength (MPa) Impact absorption energy (-60℃) (J) CTOD (-20℃) (mm) Comparative Example 2 662 118 0.502

[0063] Comparative Example 1

[0064] A high fracture toughness titanium-cored welding wire for marine engineering, the welding wire having a diameter of 1.2 mm, wherein the flux core comprises the following components in parts by weight: 39 parts titanium dioxide, 3 parts zirconium oxide, 3.5 parts quartz, 1.5 parts potassium fluorosilicate, 1.5 parts sodium fluoroaluminate, 2.5 parts potassium titanate, 2 parts sodium titanate, 14 parts silicon-manganese alloy, 5 parts metallic manganese powder, 5 parts atomized magnesium powder, 12 parts nickel powder, 3 parts titanium-boron alloy, and 8 parts iron powder.

[0065] The flux core accounts for 13% of the total weight of the welding wire.

[0066] Chemical composition of flux-cored wire deposited metal:

[0067] Testing items C S Mn Si P Ni Ti B Comparative Example 1 0.041 0.006 1.54 0.32 0.008 1.52 0.051 0.0031

[0068] Mechanical properties of flux-cored wire deposited metal:

[0069] Testing items Tensile strength (MPa) Impact absorption energy (-60℃) (J) CTOD (-20℃) (mm) Comparative Example 1 607 56 0.153

[0070] Comparative Example 2

[0071] A high fracture toughness titanium-cored welding wire for marine engineering, the welding wire having a diameter of 1.2 mm, wherein the flux core comprises the following components in parts by weight: 40 parts titanium dioxide, 3 parts zirconium oxide, 3.5 parts quartz, 1.5 parts potassium fluorosilicate, 1.5 parts sodium fluoroaluminate, 2.5 parts potassium titanate, 2 parts sodium titanate, 6 parts manganese monoxide, 14 parts silicon-manganese alloy, 5 parts metallic manganese powder, 12 parts nickel powder, 3 parts titanium-boron alloy, and 6 parts iron powder.

[0072] The flux core accounts for 13% of the total weight of the welding wire.

[0073] Chemical composition of flux-cored wire deposited metal:

[0074] Testing items C S Mn Si P Ni Ti B Comparative Example 2 0.039 0.005 1.55 0.31 0.009 1.55 0.048 0.0028

[0075] Mechanical properties of flux-cored wire deposited metal:

[0076] Testing items Tensile strength (MPa) Impact absorption energy (-60℃) (J) CTOD (-20℃) (mm) Comparative Example 2 595 34 0.127

[0077] Comparative Example 3

[0078] A high fracture toughness titanium-cored welding wire for marine engineering, the welding wire having a diameter of 1.2 mm, wherein the flux core comprises the following components in parts by weight: 40 parts titanium dioxide, 3 parts zirconium oxide, 3.5 parts quartz, 1.5 parts potassium fluorosilicate, 1.5 parts sodium fluoroaluminate, 2.5 parts potassium titanate, 2 parts sodium titanate, 14 parts silicon-manganese alloy, 5 parts metallic manganese powder, 6 parts atomized magnesium powder, 12 parts nickel powder, 3 parts titanium-boron alloy, and 6 parts iron powder.

[0079] The flux core accounts for 13% of the total weight of the welding wire.

[0080] Chemical composition of flux-cored wire deposited metal:

[0081] Testing items C S Mn Si P Ni Ti B Comparative Example 3 0.038 0.007 1.58 0.35 0.008 1.56 0.052 0.0031

[0082] Mechanical properties of flux-cored wire deposited metal:

[0083] Testing items Tensile strength (MPa) Impact absorption energy (-60℃) (J) CTOD (-20℃) (mm) Comparative Example 3 658 62 0.165

[0084] The mechanical properties of the weld metal deposited by the flux-cored welding wire can be seen from the above data. Manganese monoxide and atomized magnesium powder in the deoxidizer have a synergistic effect in enhancing the low-temperature impact toughness and fracture toughness of the weld metal, and can be applied to the welding of steel plates for offshore platform structures.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high fracture toughness titanium-type flux-cored welding wire for marine engineering, characterized in that: Welding wire cores include non-metallic flux powder and metallic flux powder; The non-metallic powder comprises the following components in parts by weight: 36 to 42 parts titanium dioxide powder, 2 to 5 parts zirconium oxide powder, 2 to 4 parts quartz, 1 to 2 parts potassium fluorosilicate, 1 to 2 parts sodium fluoroaluminate, 3 to 6 parts potassium sodium arc stabilizer, and 1 to 3 parts manganese monoxide. The metallic powder comprises the following components in parts by weight: 12 to 16 parts silicon-manganese alloy, 4 to 6 parts metallic manganese powder, 2 to 5 parts atomized magnesium powder, 10 to 14 parts nickel powder, 2 to 4 parts titanium-boron alloy, and 3 to 12 parts iron powder.

2. The high fracture toughness titanium-cored welding wire for marine engineering according to claim 1, characterized in that: The flux core of the welding wire accounts for 12% to 14% of the total mass of the welding wire.

3. The high fracture toughness titanium-cored welding wire for marine engineering according to claim 1, characterized in that: The mass fraction of TiO2 in the titanium dioxide powder is ≥97%.

4. The high fracture toughness titanium-type flux-cored welding wire for marine engineering according to claim 1, characterized in that: The zirconium oxide powder contains ≥98% ZrO2 by mass.

5. The high fracture toughness titanium-cored welding wire for marine engineering as described in claim 1, characterized in that: The mass fraction of Ni in the nickel powder is ≥99%.

6. The high fracture toughness titanium-type flux-cored welding wire for marine engineering according to claim 1, characterized in that: The flux-cored welding wire has a tensile strength of 550-720 MPa, a yield strength of ≥460 MPa, an elongation of ≥20%, an impact toughness of ≥60 J at -60℃, and a fracture toughness index of the welded joint: crack tip expansion displacement CTOD at -20℃ ≥0.3 mm.

7. A method for preparing a high fracture toughness titanium-cored welding wire for marine engineering as described in any one of claims 1-6, characterized in that: The method includes the following steps: 1) Prepare non-metallic and metallic medicinal powders in proportion, and bake the non-metallic and metallic medicinal powders. 2) Mix the baked non-metallic and metallic powders together and stir. 3) Cut the steel strip; 4) The mixed non-metallic and metallic powders are fed together with the steel strip to the forming machine for rolling and drawing. 5) Vacuum package the finished welding wire.

8. The application of the high fracture toughness titanium-cored welding wire for marine engineering as described in any one of claims 1-6 in the welding of steel plates for marine platform structures.