A medium-high strength high-toughness stranded welding wire and a preparation method and application thereof

Abstract

The application provides a medium-high toughness stranded welding wire and a preparation method and application thereof, and belongs to the technical field of welding materials. The brittle carbide and quenching are reduced from the root by controlling the content of C; the martensite transformation temperature Ms is greatly reduced by controlling the content of Ni, the formation of austenite with better and more stable toughness is promoted, and in the subsequent cooling or low-temperature tempering process, the nanoscale second phase rich in Ni is precipitated, when the impact or low-temperature deformation is received, the energy can be absorbed through the mechanism of slip, stacking fault and the like, the crack tip is passivated, and thus the low-temperature toughness is improved; the austenite can also absorb the hydrogen and stress in the HAZ area, and reduce the brittleness of the HAZ area; the content of Cr, Ni and Mo elements is controlled, the solid solution strengthening is cooperatively carried out, and part of the reversed austenite is stabilized; V, Al, Ti and B are added, the fine intermetallic compound is formed, and the nanoscale second phase in the weld as the pinning dislocation and the refined structure is formed.

Description

Technical Field

[0001] This invention belongs to the field of welding materials technology, specifically relating to a medium-strength, high-toughness stranded welding wire, its preparation method, and its application. Background Technology

[0002] Modern heavy equipment, such as main battle tanks and armored personnel carriers, mainly uses low-alloy high-strength armor steel plates with a yield strength of ≥700MPa to balance protection and weight.

[0003] Welding this type of steel has always been a technical challenge in manufacturing, especially in low-temperature service environments. The low-temperature toughness of the weld and heat-affected zone (HAZ) drops sharply, making it prone to brittle fracture and seriously threatening structural safety. Existing welding materials for this type of ultra-high-strength steel mainly face the following challenges: a prominent contradiction between strength and toughness. Matching welding wires usually aim for equal or ultra-high strength matching, resulting in a complex weld alloy system with high carbon equivalent and insufficient ductility and toughness reserves. Under rapid cooling conditions after welding, the weld is prone to forming lath martensite or bainite with high dislocation density, resulting in high strength but poor toughness and sensitivity to hydrogen-induced cold cracking; insufficient low-temperature toughness. Conventional high-strength steel welding wires have a high ductile-brittle transition temperature, and the impact energy decays severely at -40°C or even lower temperatures, which cannot meet the requirements of armored vehicles in high-altitude and cold regions for the weld's resistance to dynamic tearing. Summary of the Invention

[0004] The purpose of this invention is to provide a medium-strength, high-toughness stranded welding wire, its preparation method, and its applications. The medium-strength, high-toughness stranded welding wire provided by this invention can simultaneously improve the strength and toughness of the weld, exhibiting low crack sensitivity and high low-temperature toughness.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a medium-strength, high-toughness welding material, comprising, by mass percentage: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Cr 18.0~19.5%, Ni 12.0~13.5%, Mo 2.0~2.7%, Cu 0.01~0.3%, Co 0.1~0.3%, V 0.01~0.15%, Ti 0.01~0.06%, Al 0.005~0.03%, B 0.0005~0.002%, S≤0.01%, P≤0.015%, and the balance Fe.

[0006] Preferably, the mass ratio of Cr to Ni in the medium-strength and high-toughness welding material is (1.35~1.6):1.

[0007] Preferably, the total mass content of Mo, Cu, Co and V in the medium-strength and high-toughness welding material is 2.4~2.9%.

[0008] This invention also provides a medium-strength, high-toughness stranded welding wire, comprising a spirally stranded base wire and a regulating wire, having the chemical composition of the medium-strength, high-toughness welding material described in the above technical solution; by mass percentage, the base wire comprises: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Cr 19.0~20.5%, Ni 12.5~14.2%, Mo 2.1~2.9%, Cu 0.01~0.3%, Co 0.1~0.3%, V 0.01~0.15%, S≤0.01%, P≤0.015%, and the balance Fe; the regulating wire comprises: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Ti 0.2~1.2%, Al 0.1~0.6%, B 0.01~0.04%, S≤0.01%, P≤0.015% and balance Fe.

[0009] Preferably, the diameter of the base wire is 0.8~1.0mm; the diameter of the adjusting wire is 0.5~0.7mm.

[0010] Preferably, the preparation method of the base wire includes: batching according to chemical composition, and then sequentially performing melting, refining, casting, hot rolling, solution treatment and drawing to obtain the base wire; the melting temperature is 1540~1580℃; the heating temperature of the hot rolling is 1150~1200℃; and the solution treatment temperature is 1050~1070℃.

[0011] Preferably, the preparation method of the regulating wire includes: batching according to chemical composition, and then sequentially performing melting, refining, casting, hot rolling, heat treatment and drawing to obtain the regulating wire; the melting temperature is 1630~1660℃; the heating temperature of the hot rolling is 1100~1150℃, and the final rolling temperature is 850~880℃; the heat treatment temperature is 880~920℃.

[0012] The present invention also provides a method for preparing the medium-strength and high-toughness stranded welding wire described in the above technical solution, comprising: spirally stranding the adjusting wire and the base wire.

[0013] Preferably, the twist pitch of the spiral twist is 15~18mm.

[0014] The present invention also provides the application of the medium-strength and high-toughness welding material or the medium-strength and high-toughness stranded welding wire described in the above technical solution in the welding of low alloy high-strength steel.

[0015] This invention provides a medium-strength, high-toughness welding material, comprising, by mass percentage: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Cr 18.0~19.5%, Ni 12.0~13.5%, Mo 2.0~2.7%, Cu 0.01~0.3%, Co 0.1~0.3%, V 0.01~0.15%, Ti 0.01~0.06%, Al 0.005~0.03%, B 0.0005~0.002%, S≤0.01%, P≤0.015%, and the balance Fe. This invention reduces brittle carbides and hardenability at the source by controlling the C content; it significantly lowers the martensitic transformation temperature Ms by controlling the Ni content, promoting the formation of more stable and tougher austenite, and also precipitates Ni-rich nanoscale second phases during subsequent cooling or low-temperature tempering. These second phases can absorb energy through mechanisms such as slip and stacking faults when subjected to impact or low-temperature deformation, thus blunting crack tips and improving low-temperature toughness. Austenite can also absorb hydrogen and stress in the HAZ region, reducing the brittleness of the HAZ region. By controlling the content of Cr, Ni, and Mo, solid solution strengthening is carried out synergistically, and partially reversed austenite is stabilized. By adding V, Al, Ti, and B, fine intermetallic compounds are formed, which act as nanoscale second phases in the weld to pin dislocations and refine the microstructure. By controlling the S and P content, grain boundary cleanliness is ensured, reducing temper brittleness and crack sensitivity. The results of the embodiments show that the medium-strength and high-toughness stranded welding wire provided by the present invention is used for welding low-alloy high-strength steel. The room temperature yield strength of the butt weld metal reaches 554 MPa, the tensile strength reaches 712 MPa, the elongation reaches 37%, and the average Charpy V-type impact energy at -196℃ is 124 J. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the arrangement of the base filament and the regulating filament in an embodiment of the present invention; Figure 2 Metallographic structure of the weld fracture surface after welding using the stranded welding wire provided in Embodiment 1 of the present invention; Figure 3 SEM image of the weld fracture surface after welding using the stranded welding wire provided in Embodiment 1 of the present invention. Detailed Implementation

[0017] All raw materials used in this invention are not particularly limited in their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0018] There are no particular restrictions on the purity of any of the raw materials used in this invention. However, this invention preferably uses raw materials of industrial purity or conventional purity in the field of welding materials.

[0019] This invention provides a medium-strength, high-toughness welding material, comprising, by mass percentage: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Cr 18.0~19.5%, Ni 12.0~13.5%, Mo 2.0~2.7%, Cu 0.01~0.3%, Co 0.1~0.3%, V 0.01~0.15%, Ti 0.01~0.06%, Al 0.005~0.03%, B 0.0005~0.002%, S≤0.01%, P≤0.015%, and the balance Fe.

[0020] The medium-strength, high-toughness welding material provided by this invention comprises 0.01-0.03% C, preferably 0.02%, by weight percentage. A low C content can reduce the tendency for the formation of brittle and hard structures such as martensite in the weld heat-affected zone, and reduce the susceptibility to cold cracking.

[0021] The medium-strength, high-toughness welding material provided by this invention comprises 0.8-1.0% Si, preferably 0.9%, by mass percentage. When the Si content is within the above range, it can simultaneously improve the strength and toughness of the weld.

[0022] The medium-strength, high-toughness welding material provided by this invention comprises 1.5-2.0% Mn, preferably 1.6-1.9%, by mass percentage. As one embodiment of this invention, the mass content of Mn in the medium-strength, high-toughness welding material can be 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2.0%. When the mass content of Mn is within the above range, it can simultaneously improve the strength and hardenability of the weld.

[0023] The medium-strength, high-toughness welding material provided by this invention comprises 18.0-19.5% Cr by mass percentage, preferably 18.5-19.0%. As one embodiment of this invention, the Cr content in the medium-strength, high-toughness welding material can be 18.2%, 18.4%, 18.6%, 18.8%, 19.1%, or 19.3%. Within the above range, the Cr content can improve the weld's resistance to atmospheric corrosion and stress corrosion, and can also synergistically with Ni and Mo to provide solid solution strengthening and stabilize partially reversed austenite.

[0024] The medium-strength, high-toughness welding material provided by this invention comprises 12.0-13.5% Ni by mass percentage, preferably 12.5-13.0%. As one embodiment of this invention, the mass content of Ni in the medium-strength, high-toughness welding material can be 12.2%, 12.4%, 12.6%, 12.8%, 13.1%, or 13.3%. Within the above range, the Ni mass content can significantly reduce the martensitic transformation temperature Ms, promote the formation of more stable and tougher austenite, and also precipitate Ni-rich nanoscale second phases during subsequent cooling or low-temperature tempering. When subjected to impact or low-temperature deformation, these phases can absorb energy through mechanisms such as slip and stacking faults, passivating crack tips and thereby improving low-temperature toughness.

[0025] In this invention, the preferred mass ratio of Cr to Ni in the medium-strength, high-toughness welding material is (1.35~1.6):1, more preferably (1.45~1.55):1. This Cr to Ni mass ratio is beneficial for further stabilizing austenite and improving the toughness of the weld.

[0026] The medium-strength, high-toughness welding material provided by this invention comprises 2.0-2.7% Mo by mass percentage, preferably 2.3-2.5%. As one embodiment of this invention, the mass content of Mo in the medium-strength, high-toughness welding material can be 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, or 2.6%. A Mo mass content within the above range can reduce temper brittleness and also provide solid solution strengthening, thereby improving the strength of the weld.

[0027] The medium-strength, high-toughness welding material provided by this invention comprises 0.01-0.3% Cu by mass percentage, preferably 0.05-0.2%. As one embodiment of this invention, the mass content of Cu in the medium-strength, high-toughness welding material can be 0.03%, 0.06%, 0.09%, 0.12%, 0.15%, 0.22%, or 0.26%. A Cu mass content within the above range can improve the hardenability, strength, and toughness of the weld.

[0028] The medium-strength, high-toughness welding material provided by this invention comprises 0.1-0.3% Co by mass percentage, preferably 0.15-0.25%. As one embodiment of this invention, the mass content of Co in the medium-strength, high-toughness welding material can be 0.13%, 0.15%, 0.16%, 0.19%, 0.22%, 0.25%, or 0.27%. A Co mass content within the above range can improve the strength and toughness of the weld.

[0029] The medium-strength, high-toughness welding material provided by this invention comprises 0.01-0.15% V, preferably 0.05-0.1%, by mass percentage. As one embodiment of this invention, the mass content of V in the medium-strength, high-toughness welding material can be 0.03%, 0.05%, 0.06%, 0.09%, 0.11%, 0.13%, or 0.14%. A V mass content within the above range can refine the grains and improve the strength and toughness of the weld.

[0030] In this invention, the total mass content of Mo, Cu, Co, and V in the medium-strength, high-toughness welding material is preferably 2.4-2.9%, more preferably 2.6-2.8%. Having the total mass content of Mo, Cu, Co, and V in the medium-strength, high-toughness welding material within the above range is beneficial for improving the high-temperature strength and secondary hardening of the weld.

[0031] The medium-strength, high-toughness welding material provided by this invention comprises 0.01-0.06% Ti by mass percentage, preferably 0.03-0.05%. As one embodiment of this invention, the mass content of Ti in the medium-strength, high-toughness welding material can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, or 0.06%. A Ti mass content within the above range can refine the grains and improve the strength and toughness of the weld.

[0032] The medium-strength, high-toughness welding material provided by this invention comprises 0.005-0.03% Al, preferably 0.01-0.02%, by mass percentage. An Al content within the above range can refine the grains and improve the strength and toughness of the weld.

[0033] The medium-strength, high-toughness welding material provided by this invention comprises 0.0005~0.002% B by mass percentage, preferably 0.001~0.0015%. A B mass content within the above range can refine the grain size and improve the strength and toughness of the weld.

[0034] The medium-strength, high-toughness welding material provided by this invention comprises S ≤ 0.01% by mass percentage. S is a harmful element that increases the hot brittleness of the weld; when the mass content of S is within the above range, the hot brittleness of the weld can be reduced.

[0035] The medium-strength, high-toughness welding material provided by this invention, by mass percentage, contains P ≤ 0.015%. P is a harmful element that increases the cold brittleness of the weld; when the mass content of P is within the above range, the cold brittleness of the weld can be reduced.

[0036] The medium-strength, high-toughness welding material provided by this invention also includes a balance of Fe. Fe is the matrix element of the medium-strength, high-toughness welding material, which can ensure the basic properties of the weld, such as strength and toughness.

[0037] This invention reduces brittle carbides and hardenability at the source by controlling the carbon content; it significantly lowers the martensitic transformation temperature (Ms) by controlling the Ni content, promoting the formation of more stable and tougher austenite, and also precipitating Ni-rich nanoscale second phases during subsequent cooling or low-temperature tempering. These second phases can absorb energy through mechanisms such as slip and stacking faults under impact or low-temperature deformation, blunting crack tips and thus improving low-temperature toughness. Austenite can also absorb hydrogen and stress in the HAZ region, reducing its brittleness. Controlling the Cr content imparts stainless steel characteristics to the weld, significantly improving its resistance to atmospheric corrosion and stress corrosion. Controlling the Cr, Ni, and Mo content synergistically strengthens the weld through solid solution and stabilizes partially reversed austenite. Adding V, Al, Ti, and B forms fine intermetallic compounds that act as nanoscale second phases in the weld, pinning dislocations and refining the microstructure. Controlling the S and P content ensures grain boundary cleanliness, reducing temper brittleness and crack susceptibility.

[0038] The present invention also provides a medium-strength, high-toughness stranded welding wire, comprising a spirally stranded base wire and an adjusting wire, having the chemical composition of the medium-strength, high-toughness welding material described in the above technical solution.

[0039] In this invention, the composition of the base wire, by mass percentage, includes: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Cr 19.0~20.5%, Ni 12.5~14.2%, Mo 2.1~2.9%, Cu 0.01~0.3%, Co 0.1~0.3%, V 0.01~0.15%, S≤0.01%, P≤0.015%, and the balance Fe; the composition of the regulating wire includes: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Ti 0.2~1.2%, Al 0.1~0.6%, B 0.01~0.04%, S≤0.01%, P≤0.015%, and the balance Fe. The composition of the base wire and the conditioning wire is within the above range, which can adjust the final composition of the welding wire.

[0040] In this invention, the diameter of the base wire is preferably 0.8~1.0 mm, more preferably 0.9 mm; the diameter of the adjusting wire is preferably 0.5~0.7 mm, more preferably 0.6 mm. Having the diameters of the base wire and the adjusting wire within these ranges facilitates spiral twisting and further improves the uniformity of the welding wire.

[0041] In one embodiment of the present invention, the medium-strength and high-toughness stranded welding wire may include 5 base wires and 1 adjusting wire, and the diameter of the medium-strength and high-toughness stranded welding wire may be 2.4 mm.

[0042] In this invention, the preparation method of the base wire preferably includes: batching according to chemical composition, and then sequentially performing melting, refining, casting, hot rolling, solution treatment and drawing to obtain the base wire; the melting temperature is preferably 1540~1580℃; the heating temperature of the hot rolling is preferably 1150~1200℃; and the solution treatment temperature is preferably 1050~1070℃. In one embodiment of the present invention, the melting apparatus is a vacuum induction furnace, and the holding time can be 40-60 minutes; the refining method can be electroslag remelting; the hot rolling holding time can be 3-4 hours, and a base wire rod with a diameter of 5.5 mm is obtained after hot rolling; the solution treatment holding time can be 20-30 minutes, and the cooling method can be water cooling; the drawing is multi-pass drawing, with a pass reduction rate of 10-25%, and intermediate annealing is performed when the cumulative reduction rate is 50%±5% and 80%±5%, respectively, at a temperature of 1010-1050℃ in a pure hydrogen atmosphere; the dimensional error of the base wire can be 0 to -0.02 mm. The preparation process and parameters of the base wire are within the above range, which is beneficial to further improve the uniformity of the welding wire.

[0043] In this invention, the preferred method for preparing the regulating wire includes: batching according to chemical composition, and then sequentially performing melting, refining, casting, hot rolling, heat treatment, and drawing to obtain the regulating wire; the melting temperature is preferably 1630~1660℃; the heating temperature of the hot rolling is preferably 1100~1150℃, and the final rolling temperature is preferably 850~880℃; the heat treatment temperature is preferably 880~920℃. In one embodiment of the present invention, the refining method can be in-furnace refining; the casting can be fully protected casting; the holding time for hot rolling can be 2-3 hours, resulting in a 5.5mm diameter regulating wire rod; the heat treatment employs a fluidized bed isothermal quenching process, with a holding time of 10-15 minutes, followed by isothermal treatment at 560℃ for 1 minute, and surface peeling; the drawing is a multi-pass drawing, with a pass reduction rate of 10-25%, and intermediate annealing is performed when the cumulative reduction rate reaches 50%±5% and 80%±5%, respectively, at a temperature of 600-650℃ in a pure hydrogen atmosphere; the dimensional error of the regulating wire can be 0.02-0mm. The preparation process and parameters of the regulating wire are within the above ranges, which is beneficial for further improving the uniformity of the welding wire.

[0044] This invention does not impose any particular limitations on other operations and parameters in the preparation of the base yarn and the regulating yarn. Conventional operations in the art can be used to obtain the base yarn and the regulating yarn that meet the requirements.

[0045] The present invention also provides a method for preparing the medium-strength and high-toughness stranded welding wire described in the above technical solution, comprising: spirally stranding the adjusting wire and the base wire.

[0046] As one embodiment of the present invention, five base wires can be arranged around one adjusting wire as the center, and then spirally twisted together.

[0047] In this invention, the twist pitch of the spiral stranding is preferably 15-18 mm, more preferably 16-17 mm; in an embodiment of this invention, the twist pitch of the spiral stranding is 16.5 mm. A twist pitch within the above range is beneficial for spiral stranding and improves the structural stability of the stranded welding wire.

[0048] The present invention does not impose any particular limitations on other parameters of the spiral stranding; parameters well known to those skilled in the art can be used to obtain stranded welding wire that meets the requirements.

[0049] The present invention also provides the application of the medium-strength and high-toughness welding material or the medium-strength and high-toughness stranded welding wire described in the above technical solution in the welding of low alloy high-strength steel.

[0050] In one embodiment of the present invention, the low-alloy high-strength steel may be 6252 armor steel.

[0051] In one embodiment of the present invention, the welding can be gas shielded welding, and the shielding gas can be high-purity argon (Ar≥99.99%) or argon-rich mixed gas (Ar+1~5% volume CO2); the welding can be multi-layer multi-pass welding; the welding current is 260A, the voltage is 24V, the welding speed is 30cm / min, and the heat input is 8~15kJ / cm; the base material is preheated during welding at a preheating temperature of 80~150℃, and the interpass temperature is ≤150℃; after welding, a heat treatment of 200℃ for 3 hours is performed.

[0052] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0053] Example 1 A medium-strength, high-toughness stranded welding wire is composed of a spirally stranded base wire and a regulating wire. By mass percentage, the composition of the medium-strength, high-toughness stranded welding wire is: C 0.02%, Si 0.9%, Mn 1.7%, Cr 19.0%, Ni 13.0%, Mo 2.5%, Cu 0.15%, Co 0.15%, V 0.1%, Ti 0.04%, Al 0.02%, B 0.0015%, S 0.005%, P 0.01%, and the balance Fe.

[0054] The preparation method is as follows: The ingredients are formulated according to the chemical composition design. The composition of the base filament, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Cr 20%, Ni 13.7%, Mo 2.6%, Cu 0.16%, Co 0.16%, V 0.11%, S 0.005%, P 0.01%, with the balance being Fe; The raw materials are heated in a vacuum induction furnace at a temperature of 1550℃ for 50 minutes to ensure that the alloying elements are fully homogenized and to effectively remove harmful gases and low-melting-point impurities. The raw materials are then refined by electroslag remelting, casting and hot rolling to obtain a base wire rod with a diameter of 5.5 mm. The hot-rolled steel ingot is heated at 1180℃ and held for 3.5 hours. The obtained base wire was solution treated at a heating temperature of 1060℃ for 25 minutes and then water cooled. The reduction rate per pass during drawing was 15%. When the cumulative reduction rate was 50% and 80%, intermediate annealing was carried out in a pure hydrogen protective atmosphere at a temperature of 1040℃. Finally, a base wire with a diameter of 0.9 (0, -0.02) mm was obtained. The ingredients are formulated according to the chemical composition design. The chemical composition of the regulating wire, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Ti 0.8%, Al 0.4%, B 0.03%, S 0.005%, P 0.01%, with the balance being Fe. The final temperature of the converter smelting is 1650℃. After refining in the furnace, it is cast under full protection to obtain the conditioning billet. The conditioning billet is heated to 1120℃ and held for 2.5h for multiple rolling passes to obtain the conditioning wire rod with a diameter of 5.5mm. The final rolling temperature is controlled at 860℃. The obtained regulating wire was subjected to continuous heat treatment using a fluidized bed isothermal quenching process. The heating temperature was 900℃, the holding temperature was 12 min, the isothermal treatment was performed at 560℃ for 1 min, and the surface was peeled before drawing. The surface reduction rate was 20% per pass, and the cumulative surface reduction rate was 50% and 80%. Intermediate annealing was carried out in a pure hydrogen protective atmosphere at a temperature of 630℃. Finally, a regulating wire with a diameter of 0.6 (0.02, 0) mm was obtained by drawing. The wires are spirally twisted together in a ratio of 5 base wires and 1 adjusting wire, with the adjusting wire in the center and the other 5 adjusting wires on the periphery (e.g., ...). Figure 1 As shown in the figure, a medium-strength and high-toughness stranded welding wire with a diameter of 2.4 mm was obtained, wherein the twist pitch during spiral stranding was 16.5 mm.

[0055] Comparative Example 1 A stranded welding wire, composed of a spirally stranded base wire and a regulating wire, wherein the composition of the medium-strength, high-toughness stranded welding wire, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Cr 19.0%, Ni 13.0%, Mo 2.5%, Cu 0.15%, Co 0.15%, V 0.1%, Ti 0.04%, Al 0.02%, S 0.005%, P 0.01%, and the balance Fe; The composition of the base wire, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Cr 20%, Ni 13.7%, Mo 2.6%, Cu 0.16%, Co 0.16%, V 0.11%, S 0.005%, P 0.01%, with the balance being Fe; The chemical composition of the regulating wire, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Ti 0.8%, Al 0.4%, S 0.005%, P 0.01%, with the balance being Fe.

[0056] The preparation method is the same as in Example 1, except that B is omitted in the adjusting wire.

[0057] Comparative Example 2 A stranded welding wire, composed of a spirally stranded base wire and a regulating wire, wherein the medium-strength, high-toughness stranded welding wire has the following composition by mass percentage: C 0.02%, Si 0.9%, Mn 1.7%, Cr 19.0%, Ni 10.0%, Mo 2.5%, Cu 0.15%, Co 0.15%, V 0.1%, Ti 0.04%, Al 0.02%, S 0.005%, P 0.01%, and the balance Fe; The composition of the base wire, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Cr 20%, Ni 10.54%, Mo 2.6%, Cu 0.16%, Co 0.16%, V 0.11%, S 0.005%, P 0.01%, with the balance being Fe; The chemical composition of the regulating wire, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Ti 0.8%, Al 0.4%, B 0.03%, S 0.005%, P 0.01%, with the balance being Fe.

[0058] The preparation method is the same as in Example 1.

[0059] Comparative Example 3 A stranded welding wire, composed of a spirally stranded base wire and a regulating wire, wherein the medium-strength, high-toughness stranded welding wire has the following composition by mass percentage: C 0.02%, Si 0.9%, Mn 1.7%, Cr 19.0%, Ni 15.0%, Mo 2.5%, Cu 0.15%, Co 0.15%, V 0.1%, Ti 0.04%, Al 0.02%, S 0.005%, P 0.01%, and the balance Fe; The composition of the base wire, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Cr 20%, Ni 15.8%, Mo 2.6%, Cu 0.16%, Co 0.16%, V 0.11%, S 0.005%, P 0.01%, with the balance being Fe; The chemical composition of the regulating wire, by mass percentage, is: C 0.02%, Si 0.9%, Mn 1.7%, Ti 0.8%, Al 0.4%, B 0.03%, S 0.005%, P 0.01%, with the balance being Fe.

[0060] The preparation method is the same as in Example 1.

[0061] Application examples The stranded welding wires provided in Example 1 and Comparative Examples 1-3 were used to weld 6252 armor steel. The welding process was as follows: 98% volume Ar + 2% CO2 was used as the shielding gas, the welding current was 260A, the voltage was 24V, the welding speed was 30cm / min, and the heat input was 12.5kJ / cm; the base material preheating temperature was 120℃, and the interpass temperature was ≤140℃; the weld was subjected to heat treatment at 200℃ for 3h.

[0062] Microscopic observation of the weld fracture surface of the sample welded using stranded welding wire from Example 1 was performed, and metallographic microstructure images were obtained, as shown below. Figure 2 As shown; the SEM image is obtained, as follows. Figure 3 As shown.

[0063] from Figure 2 It can be seen that the metallographic structure of the HAZ region (marked by the red line) is basically the same as that of the base metal, with no significant changes, thus ensuring the mechanical properties of the weld.

[0064] from Figure 3 As can be seen, the fracture surface is densely covered with dimples, which is a typical morphology of austenitic structure, indicating that the material has excellent toughness.

[0065] The mechanical properties of the butt weld metal were tested after welding, and the test results are recorded in Table 1.

[0066] Table 1. Test Records of Mechanical Properties of Welds from Different Stranded Welding Wires

[0067] As can be seen from Table 1, the stranded welding wire provided in Example 1 has good strength, toughness, and low-temperature toughness; in Comparative Example 1, due to the omission of B, the strength, toughness, and low-temperature toughness of the weld are significantly reduced; in Comparative Example 2, the Ni content is reduced, and the tensile strength and toughness of the weld are significantly reduced; in Comparative Example 3, the Ni content is increased, and the tensile strength and toughness of the weld are also reduced; This shows that the present invention effectively improves the strength, toughness, and low-temperature toughness of the weld by designing the composition of the stranded welding wire.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A medium-strength, high-toughness welding material, characterized in that, By mass percentage, it includes: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Cr 18.0~19.5%, Ni 12.0~13.5%, Mo 2.0~2.7%, Cu 0.01~0.3%, Co 0.1~0.3%, V 0.01~0.15%, Ti 0.01~0.06%, Al 0.005~0.03%, B 0.0005~0.002%, S≤0.01%, P≤0.015%, and the balance Fe.

2. The medium-strength, high-toughness welding material according to claim 1, characterized in that, The mass ratio of Cr to Ni in the medium-strength and high-toughness welding material is (1.35~1.6):

1.

3. The medium-strength, high-toughness welding material according to claim 1, characterized in that, The total mass content of Mo, Cu, Co and V in the medium-strength and high-toughness welding material is 2.4~2.9%.

4. A medium-strength, high-toughness stranded welding wire, comprising a spirally stranded base wire and an adjusting wire, characterized in that, The material comprises the chemical composition of the medium-strength, high-toughness welding material as described in any one of claims 1 to 3; the base wire, by mass percentage, comprises: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Cr 19.0~20.5%, Ni 12.5~14.2%, Mo 2.1~2.9%, Cu 0.01~0.3%, Co 0.1~0.3%, V 0.01~0.15%, S≤0.01%, P≤0.015%, and the balance Fe; the regulating wire comprises: C 0.01~0.03%, Si 0.8~1.0%, Mn 1.5~2.0%, Ti 0.2~1.2%, Al 0.1~0.6%, B 0.01~0.04%, S≤0.01%, P≤0.015%, and the balance Fe.

5. The medium-strength, high-toughness stranded welding wire according to claim 4, characterized in that, The diameter of the base wire is 0.8~1.0mm; the diameter of the adjusting wire is 0.5~0.7mm.

6. The medium-strength, high-toughness stranded welding wire according to claim 4 or 5, characterized in that, The preparation method of the base wire includes: batching according to chemical composition, and then sequentially performing melting, refining, casting, hot rolling, solution treatment and drawing to obtain the base wire; the melting temperature is 1540~1580℃; the heating temperature of the hot rolling is 1150~1200℃; and the solution treatment temperature is 1050~1070℃.

7. The medium-strength, high-toughness stranded welding wire according to claim 4 or 5, characterized in that, The preparation method of the regulating wire includes: batching according to chemical composition, and then sequentially performing melting, refining, casting, hot rolling, heat treatment and drawing to obtain the regulating wire; the melting temperature is 1630~1660℃; the heating temperature of the hot rolling is 1100~1150℃, and the final rolling temperature is 850~880℃; the heat treatment temperature is 880~920℃.

8. The method for preparing the medium-strength, high-toughness stranded welding wire according to any one of claims 4 to 7, characterized in that, include: The regulating wire and the base wire are spirally twisted together.

9. The preparation method according to claim 8, characterized in that, The twist pitch of the spiral strand is 15~18mm.

10. The application of the medium-strength and high-toughness welding material according to any one of claims 1 to 3, the medium-strength and high-toughness stranded welding wire according to any one of claims 4 to 7, or the medium-strength and high-toughness stranded welding wire prepared by the preparation method according to claim 8 or 9 in the welding of low-alloy high-strength steel.

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