Fe-mn series damping steel gas shielded flux-cored wire

Abstract

A Fe-Mn series damping steel gas shielded flux-cored wire, comprising a stainless steel sheath and a flux core, the weight of the flux core accounting for 13-15% of the total weight of the flux-cored wire, the raw material composition of the flux core and the weight percentage content thereof being as follows: 2-3% of marble, 50-55% of rutile, 3-4% of feldspar, 45 # 6-8% of ferrosilicon, 2-3% of rare earth fluoride, 5-7% of magnesium powder, 3-4% of electrolytic manganese, 2-3% of sodium fluoride, and the balance being iron powder. The present application not only has good all-position welding process performance and beautiful weld, but also has excellent mechanical properties and reaches ultra-low hydrogen level of diffusible hydrogen content of deposited metal, and can meet the welding requirements of Fe-Mn series damping steel.

Description

Technical Field

[0001] This invention belongs to the field of welding materials technology, specifically relating to a Fe-Mn damping steel gas-shielded flux-cored welding wire. Background Technology

[0002] Materials that can convert mechanical vibration into heat energy dissipation, thereby reducing noise and vibration, are collectively referred to as damping materials. Iron-based damping alloys mainly include Fe-C, Fe-Cr, Fe-Al, and Fe-Mn damping alloys. Fe-C damping alloys are cast iron, a multiphase alloy, inexpensive and easy to produce. However, cast iron has low strength, poor corrosion resistance, and high brittleness, making it difficult to meet the mechanical performance requirements of manufactured components, and its damping performance is relatively low. Fe-Al and Fe-Cr damping alloys are both ferromagnetic damping alloys. While Fe-Al damping alloys have good damping performance and strength, they suffer from significant brittleness. Fe-Cr damping alloys have good damping performance but poor toughness. Fe-Mn damping alloys have good damping performance, good mechanical properties, good machinability, and low cost, making them suitable for widespread, high-volume applications. However, currently, there is a lack of welding materials compatible with Fe-Mn damping alloys. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned problems in the existing technology by providing a Fe-Mn damping steel gas-shielded flux-cored welding wire with excellent process performance, low-temperature impact resistance, and ultra-low hydrogen levels.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] A Fe-Mn damping steel gas-shielded flux-cored welding wire includes a stainless steel outer sheath and a flux core, wherein the weight of the flux core accounts for 13%-15% of the total weight of the flux-cored welding wire.

[0006] The raw material composition and weight percentage of the core are as follows: marble 2%-3%, rutile 50%-55%, feldspar 3%-4%, 45%-5%-6%. # Ferrosilicon 6%-8%, rare earth fluoride 2%-3%, magnesium powder 5%-7%, electrolytic manganese 3%-4%, sodium fluoride 2%-3%, balance iron powder.

[0007] The stainless steel outer sheath is a low-S, low-P stainless steel strip, with the following elemental composition and weight percentage content: C 0.035%-0.045%, Si 0.30%-0.35%, Mn 8.5%-9.5%, S 0.0045%-0.0055%, P 0.0055%-0.0065%, Cr 23.5%-24.5%, Ni 13.5%-14.5%, with the balance being Fe and unavoidable impurities.

[0008] The chemical composition of the weld metal deposited by the flux-cored wire includes:

[0009] C 0.050%-0.057%, Si 0.24%-0.27%, Mn 8.0%-8.5%, S 0.004%-0.006%, P0.004%-0.006%, Ni 13.7%-13.9%, Cr 23.0%-23.8%.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] The present invention provides an Fe-Mn system damping steel gas-shielded flux-cored welding wire in which the flux core accounts for 13%-15% of the total weight of the flux-cored welding wire, and the raw material composition and weight percentage content of the flux core are: marble 2%-3%, rutile 50%-55%, feldspar 3%-4%, 45 # The flux-cored welding wire contains 6%-8% ferrosilicon, 2%-3% rare earth fluorides, 5%-7% magnesium powder, 3%-4% electrolytic manganese, 2-3% sodium fluoride, and the balance is iron powder. On the one hand, with CO2 gas protection, the welding arc is stable, the melting is uniform, the slag has good fluidity, the weld formation is beautiful, and the all-position operation process is good. On the other hand, through the reasonable design of the deposited metal composition (mainly reflected in Ni-Cr-Mn) and the design of the flux mineral composition, it effectively ensures that the average impact energy of the deposited metal at -20℃ is greater than 100J, and the diffusible hydrogen content (mercury method) of the deposited metal is less than 5.0mL / 100g, reaching the ultra-low hydrogen level, which can meet the welding requirements of Fe-Mn damping steel. Detailed Implementation

[0012] The present invention will now be described in further detail with reference to specific embodiments.

[0013] In this invention, the design principles for each component are as follows:

[0014] Sodium fluoride: It plays a role in removing hydrogen and improving fluidity. Too much sodium fluoride is not conducive to weld formation. The amount added should be controlled at 2%-3%.

[0015] Marble: Its main component is CaCO3, which decomposes into CaO and CO2 at high temperatures. It mainly plays a role in slag formation and gas generation. If the content is too low, it will not provide protection, and if the content is too high, it will cause increased splashing. Therefore, in this invention, the marble content is controlled at 2%-3%.

[0016] Rutile: Its main component is TiO2, which is the primary component forming welding slag. The addition of TiO2 can stabilize the arc, reduce welding spatter, and improve slag coverage and slag removal. In addition, TiO2 can improve slag fluidity, making all-position welding operations easier to control. When the amount of TiO2 in the flux core is too small, the above characteristics are not obvious; when the amount of TiO2 in the flux core is too large, it not only damages the slag coverage but also has an adverse effect on mechanical properties. Therefore, rutile accounts for 50%-55% of the total weight of the flux core powder.

[0017] Feldspar: Its main components are Al2O3, K2O, Na2O, and SiO2, and it is also a major component of slag. It can adjust the melting point and viscosity of the slag, improve weld formation, facilitate a smooth transition from the weld to the base metal, increase the interface between the slag and the weld, and give the slag good coverage. When the amount added to the flux core is small, these characteristics are not observed; when the amount added is large, the oxygen content in the weld increases, reducing the low-temperature impact toughness of the weld metal. Therefore, feldspar accounts for 3%-4% of the total weight of the flux core powder.

[0018] Electrolytic manganese (Mn): The main deoxidizer, used to reduce the oxygen content of weld metal, increase weld metal strength and crack resistance, improve low-temperature impact toughness, and regulate the fluidity of molten iron. Adding more than 4% Mn results in excessively high weld strength and reduced low-temperature impact toughness; therefore, Mn should account for 3%-4% of the total weight of the flux-cored powder.

[0019] Magnesium powder (Mg): a strong deoxidizer that improves low-temperature impact toughness. When its addition is less than 5%, its ability to improve low-temperature impact toughness is insufficient. When the addition of Mg is greater than 7%, the magnesium oxide deoxidation product raises the melting point of the slag and accelerates the solidification rate, which is not conducive to the removal of weld gas and weld formation. Therefore, Mg accounts for 5%-7% of the total weight of the flux core powder.

[0020] 45 # Ferrosilicon (Si-Fe): The main deoxidizer. Adding an appropriate amount can improve the process and deoxidation, while adding too much is detrimental to process performance. In this invention, magnesium powder is the main component; therefore, 45... # Ferrosilicon accounts for 6%-8% of the total weight of the core powder.

[0021] S and P: Impurity elements that severely affect the weld metal's resistance to hydrogen sulfide and reduce its low-temperature impact toughness. S forms sulfide inclusions with elements such as Fe, which can induce pitting corrosion and stress corrosion cracking. P has a strong segregation effect, causing unevenness in the weld metal, especially increasing cold brittleness. Therefore, the lower the content of S and P, the better.

[0022] Rare earth fluorides: can purify welds and improve the low-temperature impact toughness of welds. However, adding too much will not have a significant effect. Due to the high price of rare earths, their percentage of the total weight of the core powder should be controlled at 2%-3%.

[0023] Iron powder: can improve the state of the electric arc, adjust the melting point and viscosity of molten iron, and add the remainder.

[0024] The welding conditions for the flux-cored welding wire described in this invention are as follows:

[0025] CO2 with a purity of 99.5% or higher is used as the protective gas;

[0026] Welding current 200-240A;

[0027] Welding voltage 24-28V;

[0028] Welding speed: 26-35 cm / min.

[0029] Example 1:

[0030] A Fe-Mn damping steel gas-shielded flux-cored welding wire includes a stainless steel outer sheath and a flux core. The flux core accounts for 15% of the total weight of the flux-cored welding wire. The raw material composition and weight percentage content of the flux core are: marble 2%, rutile 50%, feldspar 3%, and 45%. # The composition includes 6% ferrosilicon, 2% rare earth fluoride, 5% magnesium powder, 3% electrolytic manganese, 2% sodium fluoride, and the balance being iron powder; the stainless steel outer sheath is a low-S, low-P stainless steel strip, with the elemental composition and weight percentage content as follows: C 0.035%, Si 0.30%, Mn 9.0%, S 0.0055%, P 0.0065%, Cr 24.5%, Ni 14.0%, and the balance being Fe and unavoidable impurities.

[0031] The chemical composition of the weld metal deposited by the flux-cored wire includes: C 0.050%, Si 0.24%, Mn 8.1%, S 0.006%, P 0.006%, Ni 13.8%, and Cr 23.8%.

[0032] The mechanical properties of the weld metal and the test results of the diffusible hydrogen content of the flux-cored welding wire are shown in Table 1 and Table 2, respectively.

[0033] Example 2:

[0034] The difference from Example 1 is as follows:

[0035] The flux core accounts for 13% of the total weight of the flux-cored welding wire. The raw material composition and weight percentage of the flux core are: marble 3%, rutile 55%, feldspar 4%, and 45%. # The stainless steel outer skin contains 8% ferrosilicon, 3% rare earth fluoride, 7% magnesium powder, 4% electrolytic manganese, 3% sodium fluoride, and the balance is iron powder; the elemental composition and weight percentage of the stainless steel outer skin are: C 0.04%, Si 0.33%, Mn 9.5%, S 0.0050%, P 0.0055%, Cr 24.5%, Ni 14.5%, and the balance is Fe and unavoidable impurities.

[0036] The chemical composition of the weld metal deposited by the flux-cored wire includes: C 0.053%, Si 0.26%, Mn 8.5%, S 0.005%, P 0.004%, Ni 13.9%, and Cr 23.8%.

[0037] The mechanical properties of the weld metal and the test results of the diffusible hydrogen content of the flux-cored welding wire are shown in Table 1 and Table 2, respectively.

[0038] Example 3:

[0039] The difference from Example 1 is as follows:

[0040] The flux core accounts for 14% of the total weight of the flux-cored welding wire. The raw material composition and weight percentage of the flux core are: marble 3%, rutile 53%, feldspar 3.5%, 45 # The composition is as follows: 7% ferrosilicon, 3% rare earth fluoride, 6% magnesium powder, 3.5% electrolytic manganese, 2% sodium fluoride, with the balance being iron powder; the stainless steel outer sheath is a low-S, low-P stainless steel strip, with the elemental composition and weight percentage content as follows: C 0.045%, Si 0.35%, Mn 8.5%, S 0.0045%, P 0.0060%, Cr 23.5%, Ni 13.5%, with the balance being Fe and unavoidable impurities.

[0041] The chemical composition of the weld metal deposited by the flux-cored wire includes: C 0.057%, Si 0.27%, Mn 8.0%, S 0.004%, P 0.005%, Ni 13.7%, and Cr 23.0%.

[0042] The mechanical properties of the weld metal and the test results of the diffusible hydrogen content of the flux-cored welding wire are shown in Table 1 and Table 2, respectively.

[0043] Table 1 Mechanical properties of weld metal deposited with flux-cored wire

[0044] serial number <![CDATA[ Rm / MPa ]]> A / ％ <![CDATA[KV2(-20℃) / J (Test group 3)]]> Example 1 624 33 101、114、124 Example 2 641 36 104、112、103 Example 3 632 37 111、125、125

[0045] Table 2. Test results of diffuse hydrogen content in flux-cored wires

[0046]

[0047] The above embodiments are merely illustrative examples of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A Fe-Mn damping steel gas-shielded flux-cored welding wire, comprising a stainless steel sheath and a flux core, characterized in that: The weight of the flux core accounts for 13%-15% of the total weight of the flux-cored welding wire; The raw material composition and weight percentage of the core are as follows: marble 2%-3%, rutile 50%-55%, feldspar 3%-4%, 45# ferrosilicon 6%-8%, rare earth fluoride 2%-3%, magnesium powder 5%-7%, electrolytic manganese 3%-4%, sodium fluoride 2%-3%, and the balance is iron powder. The stainless steel outer sheath is a low-S, low-P stainless steel strip, with the following elemental composition and weight percentage content: C 0.035%-0.045%, Si 0.30%-0.35%, Mn 8.5%-9.5%, S 0.0045%-0.0055%, P 0.0055%-0.0065%, Cr 23.5%-24.5%, Ni 13.5%-14.5%, with the balance being Fe and unavoidable impurities.

2. The Fe-Mn damping steel gas-shielded flux-cored welding wire according to claim 1, characterized in that: The chemical composition of the weld metal deposited by the flux-cored wire includes: C 0.050%-0.057%, Si 0.24%-0.27%, Mn 8.0%-8.5%, S 0.004%-0.006%, P 0.004%-0.006%, Ni 13.7%-13.9%, Cr 23.0%-23.8%.

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