A duplex stainless steel welding wire and a method of manufacturing the same

Abstract

The present disclosure provides a duplex stainless steel welding wire and a preparation method thereof. The content of each element in the duplex stainless steel welding wire provided by the present disclosure is expressed as follows in percentage by weight: C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe. By reasonably adjusting the content of each element, smelting the alloy solution of the duplex stainless steel welding wire, and after continuous casting, cutting, hot rolling, and drawing, a super duplex stainless steel welding wire with high strength and high corrosion resistance is obtained; the duplex stainless steel welding wire has a short production cycle, a high yield, and a simple production process control, thereby reducing the production cost.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of metal manufacturing, and in particular to a duplex stainless steel welding wire and a preparation method thereof. BACKGROUND

[0002] Super duplex stainless steel has about 50% of ferrite and about 50% of austenite, and has high strength and high corrosion resistance. Compared with super austenitic stainless steel and nickel-based alloy materials with similar properties, super duplex stainless steel has a cost advantage, and is increasingly widely used in extremely harsh corrosion environments, such as offshore oil platforms, seawater desalination, and other industrial fields.

[0003] Welding is one of the key technologies for the application of super duplex stainless steel. The welded joint is a weak link of the duplex stainless steel welded structure, and the welding wire is a welding material with high efficiency, low cost, and high quality. At present, the production of super duplex stainless steel welding wire mostly adopts die casting, which has a long production cycle, low material yield, high processing cost, and unstable surface quality. SUMMARY

[0004] To solve the problems in the related art, the present disclosure provides a duplex stainless steel welding wire and a preparation method thereof.

[0005] In a first aspect of the exemplary embodiments of the present disclosure, a duplex stainless steel welding wire is provided, which comprises the following elements, expressed in weight percentage as follows:

[0006] C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe.

[0007] In some exemplary embodiments, the sum of the weight percentages of Ni+30(C+N)+Mn is 13-29%.

[0008] In some exemplary embodiments, the sum of the weight percentages of Cr+3Mo+Si is 31-49%.

[0009] In some exemplary embodiments, C: 0.01-0.02%, Si: 0.5-1.0%, Mn: 1.0-2.5%, Cr: 26.0-28.0%, Ni: 9.0-11.0%, Mo: 3.0-5.0%, Cu: 1.0-1.5%, N: 0.2-0.3%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.020%, and the balance of Fe;

[0010] wherein the sum of the weight percentages of Ni+30(C+N)+Mn is 16-22%; and the sum of the weight percentages of Cr+3Mo+Si is 35-45%.

[0011] In a second aspect of the exemplary embodiments of the present disclosure, a preparation method of a duplex stainless steel welding wire is provided, the preparation method is used for preparing the duplex stainless steel welding wire described above, and the preparation method comprises the following steps:

[0012] S100: smelting according to the element weight percentages of the duplex stainless steel welding wire described above to obtain an alloy solution of the duplex stainless steel welding wire;

[0013] S200: after the alloy solution of the duplex stainless steel welding wire in step S100 is subjected to continuous casting, cutting, hot rolling of a rod, and drawing, the duplex stainless steel welding wire is obtained.

[0014] In some exemplary embodiments, step S100 comprises:

[0015] S101: smelting in a Consteel electric furnace according to the element weight percentages of 1.0%<C<1.5%, Si≤1.0%, Cr: 2-4%, Ni: 11-13%, P<0.02%, and the balance of Fe to obtain a first molten steel, and the tapping temperature is controlled to be 1580-1630°C;

[0016] S102: smelting in a medium-frequency furnace according to the element weight percentages of P<0.02%, Cr: 50-60%, Mo: 10-12%, and the balance of Fe to obtain a second molten steel, and the tapping temperature is controlled to be 1580-1630°C;

[0017] S103: mixing the first molten steel and the second molten steel in an AOD furnace (Argon Oxygen Decarburization Furnace) to perform preliminary refining, and after reduction, desulfurization, and deoxidation treatment, a third molten steel is obtained, and the tapping temperature is controlled to be 1580-1620°C;

[0018] S104: transferring the third molten steel to a LF furnace (Ladle Furnace) for further refining, adjusting the element components according to the element weight percentage of the duplex stainless steel welding wire as described above, adding B line, blowing argon at a flow rate less than 30 L / min for 15-20 min, and finally obtaining the alloy solution of the duplex stainless steel welding wire.

[0019] In some exemplary embodiments, in step S200, the continuous casting includes:

[0020] The alloy solution of the duplex stainless steel welding wire is transferred to a continuous casting machine at a temperature of 1475-1485 °C, and is continuously cast under the condition of argon protection.

[0021] In some exemplary embodiments, in step S200, the cutting and hot rolling of the wire rod includes:

[0022] In some exemplary embodiments, in step S200, the cutting and hot rolling of the wire rod includes:

[0023] The continuous casting billet is cut into a square billet with a cross section of (220-260)*(220-260) mm and a length of 1500-1600 mm.

[0024] The square billet is heated at a temperature of 1250-1270 °C for 50-70 min and then hot rolled into a wire rod with a diameter of Φ5.4-5.6 mm.

[0025] In some exemplary embodiments, in step S200, the drawing includes:

[0026] The wire rod with a diameter of Φ5.4-5.6 mm is drawn for 5-7 passes to obtain a wire rod with a diameter of 2-2.5 mm; wherein the deformation rate of each pass is 10-22%; after each drawing before the last drawing, the wire rod is annealed at an annealing temperature of 1050-1110 °C for 2-5 min.

[0027] The wire rod with a diameter of 2-2.5 mm is drawn for 7-12 passes to obtain the duplex stainless steel welding wire with a diameter of 1.15-1.2 mm; wherein the deformation rate of each pass is 7-15%, and the diameter size tolerance of the duplex stainless steel welding wire is ≤0.01 mm.

[0028] In some exemplary embodiments, in step S200, after the hot rolling of the wire rod, the preparation method further includes pickling, and the pickling includes:

[0029] The Φ5.4-5.6 mm rod is kept at 1050-1100 °C for 25-35 min, then cooled to 20-30 °C, and then pickled in a mixed solution of 100-120 g / L nitric acid + 40-50 g / L hydrofluoric acid for 55-65 min.

[0030] The duplex stainless steel welding wire of the present disclosure, by reasonably adjusting the content of each element, smelting the alloy solution of the duplex stainless steel welding wire, and after continuous casting, cutting, hot rolling rod, drawing, the super duplex stainless steel welding wire with high strength and high corrosion resistance is obtained; the duplex stainless steel welding wire has short production cycle, high yield, and simple process control in production process, and reduces production cost.

[0031] The duplex stainless steel welding wire according to the present disclosure comprises the following elements, and the content of each element is expressed as follows in percentage by weight:

[0032] C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe.

[0033] The role and content of each element in the duplex stainless steel welding wire are as follows:

[0034] C is an austenite forming element, higher C content will increase the strength of the duplex stainless steel, but too high C content will precipitate Cr carbide at the grain boundary of the duplex stainless steel, affecting the corrosion resistance of the duplex stainless steel; and too low C content will reduce the content of austenite and reduce the strength of the duplex stainless steel. Therefore, in the duplex stainless steel welding wire of the present disclosure, the weight percentage of C element is limited to 0.01-0.04%. Preferably, the weight percentage of C element is 0.01-0.02%.

[0035] Si is a deoxidizer that can remove a certain amount of oxygen in the duplex stainless steel to maintain the cleanliness of the duplex stainless steel. Too low Si content cannot achieve the effect of deoxidization, and too high Si content will deteriorate the plasticity of the duplex stainless steel. Therefore, in the duplex stainless steel welding wire of the present disclosure, the weight percentage of Si element is limited to 0.5-1.5%. Preferably, the weight percentage of Si element is 0.5-1.0%.

[0036] Mn has a weak ability to form austenite, and in the duplex stainless steel, Mn can increase the solid solubility of nitrogen in the duplex stainless steel. Too low Mn content is not conducive to the solid solution of nitrogen, and too high Mn content will form MnS inclusions, reducing the corrosion resistance of the duplex stainless steel. Therefore, in the duplex stainless steel wire of the present disclosure, the weight percentage of Mn element is limited to 0.8-3.2%. Preferably, the weight percentage of Mn element is 1.0-2.5%.

[0037] Cr is a ferrite-forming element and is also an essential element for the duplex stainless steel to maintain corrosion resistance. Too low Cr content cannot guarantee good corrosion resistance of the duplex stainless steel, and too high Cr content will lead to imbalance of the two phases of the duplex stainless steel. Therefore, in the duplex stainless steel wire of the present disclosure, the weight percentage of Cr element is limited to 24.0-30.0%. Preferably, the weight percentage of Cr element is 26.0-28.0%.

[0038] Ni is an austenite-forming element, and too low Ni content will lead to instability of austenite, reducing the corrosion resistance of the duplex stainless steel, but considering the cost, the Ni content should not be too high. Therefore, in the duplex stainless steel wire of the present disclosure, the weight percentage of Ni element is limited to 8.0-13.0%. Preferably, the weight percentage of Ni element is 9.0-11.0%.

[0039] Mo element can improve the corrosion resistance of the duplex stainless steel, especially the pitting corrosion resistance. Too low Mo content cannot guarantee excellent corrosion resistance of the duplex stainless steel, and too high Mo content will reduce the hot plasticity of the duplex stainless steel. Therefore, in the duplex stainless steel wire of the present disclosure, the weight percentage of Mo element is limited to 2.0-6.0%. Preferably, the weight percentage of Mo element is 3.0-5.0%.

[0040] Cu is an austenite-forming element, which can improve the corrosion resistance of the duplex stainless steel. Too low Cu content has no significant effect on improving the corrosion resistance of the duplex stainless steel, and too high Cu content will produce a large number of precipitates, reducing the plasticity of the duplex stainless steel. Therefore, in the duplex stainless steel wire of the present disclosure, the weight percentage of Cu element is limited to 1.0-2.5%. Preferably, the weight percentage of Cu element is 1.0-1.5%.

[0041] N is a strong austenite-forming element, and appropriate N can improve the strength of the duplex stainless steel while improving the corrosion resistance of the duplex stainless steel. Too high N content will affect the hot working performance of the duplex stainless steel material, and too low N content will lead to a decrease in the proportion of austenite. Therefore, in the duplex stainless steel wire of the present disclosure, the weight percentage of N element is limited to 0.1-0.4%. Preferably, the weight percentage of N element is 0.2-0.3%.

[0042] P, S, O are generally harmful elements in duplex stainless steel, excessive content will affect the corrosion resistance and plasticity of duplex stainless steel, and low content should be maintained as much as possible in actual production, but too low content will cause the rise of production cost. Therefore, in the duplex stainless steel welding wire of the present disclosure, the weight percentage of P element is limited to less than or equal to 0.025%, the weight percentage of S element is limited to less than or equal to 0.005%, and the weight percentage of O element is limited to less than or equal to 0.003%.

[0043] B element can refine the grain of duplex stainless steel and improve the corrosion resistance of duplex stainless steel. Too low B content cannot play the role of refining the grain, and too high B content will lead to the decrease of the plasticity of duplex stainless steel. Therefore, in the duplex stainless steel welding wire of the present disclosure, the weight percentage of B element is limited to 0.010-0.030%. Preferably, the weight percentage of B element is limited to 0.010-0.020%.

[0044] Ni, C, N, Mn are all austenite forming elements, and too high or too low total content of these elements will affect the two-phase ratio of duplex stainless steel. Therefore, in the duplex stainless steel welding wire of the present disclosure, the sum of the weight percentages of Ni+30(C+N)+Mn is limited to 13-29%. Preferably, the sum of the weight percentages of Ni+30(C+N)+Mn is limited to 16-22%.

[0045] Cr, Mo, Si are all ferrite forming elements, among which Cr element and Mo element can significantly improve the corrosion resistance of duplex stainless steel, and too low content of Cr element and Mo element cannot guarantee the corrosion resistance of duplex stainless steel, and too high content of Cr element and Mo element will also affect the two-phase ratio of duplex stainless steel. Therefore, in the duplex stainless steel welding wire of the present disclosure, the sum of the weight percentages of Cr+3Mo+Si is limited to 31-49%. Preferably, the sum of the weight percentages of Cr+3Mo+Si is limited to 35-45%.

[0046] The beneficial effects of selecting the above ranges of the content of each component in the duplex stainless steel welding wire of the present disclosure will be illustrated by specific experimental data in the examples.

[0047] The following are examples of preferred value ranges of each component included in the duplex stainless steel welding wire according to the present disclosure.

[0048] Preferred Example One

[0049] The duplex stainless steel welding wire according to the present disclosure includes the following elements, expressed in weight percentage as follows:

[0050] C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe.

[0051] Preferred Example Two

[0052] The duplex stainless steel welding wire according to the present disclosure includes the following elements, expressed in weight percent as follows:

[0053] C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe.

[0054] wherein the sum of the weight percent of Ni + 30(C+N) + Mn is 13-29%.

[0055] Preferred Example Three

[0056] The duplex stainless steel welding wire according to the present disclosure includes the following elements, expressed in weight percent as follows:

[0057] C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe.

[0058] wherein the sum of the weight percent of Ni + 30(C+N) + Mn is 13-29%; and the sum of the weight percent of Cr + 3Mo + Si is 31-49%.

[0059] Preferred Example Four

[0060] The duplex stainless steel welding wire according to the present disclosure includes the following elements, expressed in weight percent as follows:

[0061] C: 0.01-0.02%, Si: 0.5-1.0%, Mn: 1.0-2.5%, Cr: 26.0-28.0%, Ni: 9.0-11.0%, Mo: 3.0-5.0%, Cu: 1.0-1.5%, N: 0.2-0.3%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.020%, and the balance of Fe.

[0062] Preferred Example Five

[0063] The duplex stainless steel welding wire according to the present disclosure includes the following elements, expressed in weight percent as follows:

[0064] C: 0.01-0.02%, Si: 0.5-1.0%, Mn: 1.0-2.5%, Cr: 26.0-28.0%, Ni: 9.0-11.0%, Mo: 3.0-5.0%, Cu: 1.0-1.5%, N: 0.2-0.3%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.020%, and the balance of Fe;

[0065] wherein the sum of the weight percent of Ni+30(C+N)+Mn is 16-22%; and the sum of the weight percent of Cr+3Mo+Si is 35-45%.

[0066] Preferred Example Six

[0067] The duplex stainless steel welding wire according to the present disclosure includes the following elements, expressed in weight percent as follows:

[0068] C: 0.01-0.02%, Si: 0.5-1.0%, Mn: 1.0-2.5%, Cr: 26.0-28.0%, Ni: 9.0-11.0%, Mo: 3.0-5.0%, Cu: 1.0-1.5%, N: 0.2-0.3%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.020%, and the balance of Fe;

[0069] Preferred Example Seven

[0070] The duplex stainless steel welding wire according to the present disclosure includes the following elements, expressed in weight percent as follows:

[0071] C: 0.01-0.02%, Si: 0.6-0.85%, Mn: 1.2-2.0%, Cr: 26.5-27.5%, Ni: 9.0-11.0%, Mo: 3.0-4.5%, Cu: 1.2-1.5%, N: 0.2-0.3%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.015-0.020%, and the balance of Fe;

[0072] wherein the sum of the weight percentages of Ni+30(C+N)+Mn is 17-21%; and the sum of the weight percentages of Cr+3Mo+Si is 37-43%. DETAILED DESCRIPTION

[0073] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other in any manner without conflict.

[0074] In the related art, the welding wire for producing super duplex stainless steel is mainly produced by a mold casting method, and the specific steps are in turn smelting, mold casting, forging, grinding, hot rolling of a rod, and cold drawing of the welding wire. The production cycle is long, the material yield is low, the processing cost is high, and the surface quality of the welding wire is unstable.

[0075] The duplex stainless steel welding wire of the present disclosure is produced by reasonably adjusting the content of each element, smelting an alloy solution of the duplex stainless steel welding wire, and then through continuous casting, cutting, hot rolling of a rod, and drawing, a super duplex stainless steel welding wire with high strength and high corrosion resistance is obtained. Compared with the mold casting method in the prior art, the preparation method of the duplex stainless steel welding wire of the present disclosure adopts a continuous casting method, the production cycle is short, the material yield is high, and the production process is simple to control, thereby reducing the production cost.

[0076] The exemplary embodiments of the present disclosure provide a preparation method of a duplex stainless steel welding wire for preparing the duplex stainless steel welding wire of the present disclosure, and the preparation method comprises the following steps:

[0077] The first molten steel is obtained by smelting in a Consteel electric furnace according to the element weight percentages of 1.0%<C<1.5%, Si≤1.0%, Cr: 2-4%, Ni: 11-13%, P<0.02%, and the balance of Fe, and the tapping temperature is controlled to be 1580-1630°C.

[0078] The second molten steel is obtained by smelting in a medium frequency furnace according to the element weight percentage of P: 0.02%, Cr: 50-60%, Mo: 10-12%, and the balance of Fe.

[0079] The first molten steel and the second molten steel are mixed in an AOD furnace for preliminary refining, and ferrosilicon + aluminum blocks are used for reduction; after reduction, a double slag method is used for desulfurization, and the weight percentage content of S element is controlled to be below 0.001%; at the end of desulfurization, aluminum blocks are added for deoxidization to prevent carbon and phosphorus increase, and the third molten steel is obtained, with the tapping temperature controlled to be 1580-1620°C.

[0080] The third molten steel is transferred to an LF furnace for further refining, and the element components are adjusted according to the element weight percentage of C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe in the duplex stainless steel welding wire; the B wire is fed at 20-25 m, and after the wire feeding, no alloy is added; argon gas is blown at a flow rate of less than 30 L / min for 15-20 minutes, and finally the alloy solution of the duplex stainless steel welding wire is obtained, wherein the element content in the alloy solution is C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe, and the weight percentage sum of Ni+30(C+N)+Mn is 13-29%, and the weight percentage sum of Cr+3Mo+Si is 31-49%.

[0081] The alloy solution of the duplex stainless steel welding wire is sent to a continuous casting machine through a ladle, and the ladle temperature is controlled to be 1475-1485°C, and the first ladle temperature can be controlled according to the upper limit, and the second ladle temperature can be controlled according to the lower limit. Argon gas is blown for protection during the whole continuous casting process; wherein, the tundish temperature is controlled to be 1445-1455°C during the continuous casting, the continuous casting speed is controlled to be 0.7-0.8 m / min, the immersion nozzle depth is controlled to be 130-140 mm, and the thickness of the obtained continuous casting billet is controlled to be 220-260 mm, and the width is controlled to be 1500-1600 mm.

[0082] The continuous casting billet is cut into a square billet with a cross section of (220-260)*(220-260) mm and a length of 1500-1600 mm; the square billet is heated at a temperature of 1250-1270 °C for 50-70 min, for example, heated for 60 min, and then hot-rolled into a Φ5.4-5.6 mm rod, for example, hot-rolled into a Φ5.5 mm rod.

[0083] The above rod is kept at a temperature of 1050-1100 °C for 25-35 min, for example, kept for 30 min, and then cooled to 20-30 °C, for example, water-cooled to room temperature, and then pickled in a mixed solution of 100-120 g / L nitric acid + 40-50 g / L hydrofluoric acid for 55-65 min, for example, pickled for 60 min.

[0084] The above pickled rod is drawn in 5-7 passes to obtain a rod with a diameter of 2-2.5 mm; wherein the deformation rate of each pass is 10-22%; after each pass before the last pass, the rod is annealed at a temperature of 1050-1110 °C for 2-5 min.

[0085] The rod with a diameter of 2-2.5 mm is further drawn in 7-12 passes to obtain a dual-phase stainless steel welding wire with a diameter of 1.15-1.2 mm; wherein the deformation rate of each pass is 7-15%, and the diameter size tolerance of the dual-phase stainless steel welding wire is ≤0.01 mm.

[0086] A specific example of the preparation method of the dual-phase stainless steel welding wire provided by the exemplary embodiment of the present disclosure is given below.

[0087] According to the element weight percentages of C 1.1%, Si 0.7%, Cr 2.9%, Ni 11.9%, P 0.015%, and the balance of Fe, a first molten steel is smelted in a Consteel electric furnace, and the tapping temperature is controlled at 1610 °C.

[0088] According to the element weight percentages of P 0.016%, Cr 55.5%, Mo 11.2%, and the balance of Fe, a second molten steel is smelted in a medium-frequency furnace, and the tapping temperature is controlled at 1600 °C.

[0089] The first molten steel and the second molten steel are mixed and subjected to preliminary refining in an AOD furnace, and silicon iron + aluminum blocks are used for reduction; after reduction, a double-slag method is used for desulfurization, and the weight percentage content of S element is controlled at 0.0008%; at the end of desulfurization, aluminum blocks are added for deoxidization to prevent carbon and phosphorus increase, and a third molten steel is obtained, and the tapping temperature is controlled at 1590 °C.

[0090] The third molten steel is transferred to the LF furnace for further refining, and the elements are adjusted according to the element weight percentages of C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe in the dual-phase stainless steel welding wire. The B wire 23m is fed, and no alloy is added after feeding. Argon is blown at a flow rate of 25L / min for 20 minutes, and finally the alloy solution of the dual-phase stainless steel welding wire is obtained, wherein the element content in the alloy solution is C 0.015%, Si 0.7%, Mn 1.8%, Cr 26.5%, Ni 9.9%, Mo 3.7%, Cu 1.2%, N 0.23%, P 0.021%, S 0.002%, O 0.0025%, B 0.015%, and the balance of Fe. The sum of the weight percentages of Ni+30(C+N)+Mn is 19.05%, and the sum of the weight percentages of Cr+3Mo+Si is 38.3%.

[0091] The alloy solution of the dual-phase stainless steel welding wire is sent to the continuous casting machine by the ladle, and the temperature of the ladle is controlled at 1480°C. Argon is blown during the whole continuous casting process. The temperature of the tundish is controlled at 1450°C during the continuous casting, and the casting speed is controlled at 0.75m / min. The immersion nozzle depth is 135mm, and the thickness of the obtained continuous casting billet is controlled at 220mm, and the width is controlled at 1530mm.

[0092] The continuous casting billet is cut into a square billet with a cross section of 220*220mm and a length of 1530mm. The square billet is heated at a temperature of 1260°C for 60min, and then hot-rolled into a Φ5.5mm wire rod.

[0093] The wire rod is acid washed in a mixed solution of 110g / L nitric acid+45g / L hydrofluoric acid for 60min after being kept at a temperature of 1080°C for 30min and then water-cooled to room temperature.

[0094] The wire rod after acid washing is rough-drawn, and the drawing process is: Φ5.5mm-Φ4.9mm-Φ4.0mm-Φ3.3mm-Φ2.8mm-Φ2.5mm. The wire rod is annealed after each drawing before the last drawing, and the annealing temperature is 1080°C, and the holding time is 3min.

[0095] The wire rod with a diameter of 2.5 mm is further refined, and the drawing process is as follows: Φ2.5 mm-Φ2.1 mm-Φ1.9 mm-Φ1.7 mm-Φ1.55 mm-Φ1.45 mm-Φ1.35 mm-Φ1.25 mm-Φ1.17 mm, so as to obtain the super duplex stainless steel welding wire with a nominal diameter of Φ1.2 mm.

[0096] In the exemplary embodiments of the present disclosure, the specific content values of the elements C, Si, Mn, Cr, Ni, Mo, Cu, N, P, S, O, B and Fe in the duplex stainless steel welding wire of the present disclosure are selected as the embodiments, and three performance parameters, i.e., tensile strength (MPa), elongation (%) and pitting corrosion rate (g / (m 2 ·h)) are selected to illustrate the beneficial effects of the duplex stainless steel welding wire of the present disclosure.

[0097] The above three parameters and their determination methods are well known to those skilled in the art, and therefore the above parameters can effectively illustrate the strength and corrosion resistance of the duplex stainless steel welding wire of the present disclosure.

[0098] Table 1 shows the element composition and performance test results of the duplex stainless steel welding wires of Examples 1-9 and the comparative Example 1. The content of each element is expressed by weight percentage. It should be noted that the total content of the components in the examples is slightly less than 100%, which can be understood as trace impurities or a small amount of components that cannot be analyzed.

[0099] Table 1

[0100]

[0101]

[0102] From the test results of the above examples and the comparative example, it can be seen that the duplex stainless steel of the present disclosure has higher tensile strength, higher elongation and lower pitting corrosion rate. In addition, the duplex stainless steel welding wire of the present disclosure is prepared by continuous casting, which has a short production cycle, high material yield, simple production process control and low production cost.

[0103] Finally, it should be noted that in this document, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or equipment.

[0104] The above examples are only used to illustrate the technical solutions of the present disclosure, rather than limit them. Although the present disclosure is described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A duplex stainless steel welding wire, characterized by The duplex stainless steel welding wire comprises the following elements in the following weight percentages: C: 0.01-0.04%, Si: 0.5-1.5%, Mn: 0.8-3.2%, Cr: 24.0-30.0%, Ni: 8.0-13.0%, Mo: 2.0-6.0%, Cu: 1.0-2.5%, N: 0.1-0.4%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.030%, and the balance of Fe; The sum of the weight percentages of Ni+30(C+N)+Mn is 13-29%; The sum of the weight percentages of Cr+3Mo+Si is 31-49%.

2. The duplex stainless steel welding wire according to claim 1, characterized in that, C: 0.01-0.02%, Si: 0.5-1.0%, Mn: 1.0-2.5%, Cr: 26.0-28.0%, Ni: 9.0-11.0%, Mo: 3.0-5.0%, Cu: 1.0-1.5%, N: 0.2-0.3%, P≤0.025%, S≤0.005%, O≤0.003%, B: 0.010-0.020%, and the balance of Fe; The sum of the weight percentages of Ni+30(C+N)+Mn is 16-22%; and the sum of the weight percentages of Cr+3Mo+Si is 35-45%.

3. A method of producing a duplex stainless steel welding wire, characterized by, The preparation method is used for preparing the duplex stainless steel welding wire according to any one of claims 1-2, and the preparation method comprises the following steps: S100: smelting according to the element weight percentages of the duplex stainless steel welding wire according to any one of claims 1-2 to obtain an alloy solution of the duplex stainless steel welding wire; S200: after the alloy solution of the duplex stainless steel welding wire in step S100 is subjected to continuous casting, cutting, hot rolling of a rod, and drawing, the duplex stainless steel welding wire is obtained.

4. The method of producing a duplex stainless steel welding wire according to claim 3, characterized in that, Step S100 comprises: S101: smelting according to the element weight percentages of C>1.0%, Si≤1.0%, Cr: 2-4%, Ni: 11-13%, P<0.02%, and the balance of Fe in a Consteel electric furnace to obtain a first molten steel, and the tapping temperature is controlled to be 1580-1630°C; S102: smelting according to the element weight percentages of P<0.02%, Cr: 50-60%, Mo: 10-12%, and the balance of Fe in a medium-frequency furnace to obtain a second molten steel, and the tapping temperature is controlled to be 1580-1630°C; S103: mixing the first molten steel and the second molten steel in an AOD furnace for preliminary refining, and after reduction, desulfurization, and deoxidation treatment, a third molten steel is obtained, and the tapping temperature is controlled to be 1580-1620°C; S104: transferring the third molten steel to an LF furnace for further refining, adjusting the element components according to the element weight percentages of the duplex stainless steel welding wire according to any one of claims 1-2, adding a B wire, and blowing argon gas at a flow rate of less than 30 L / min for 15-20 minutes, and finally obtaining the alloy solution of the duplex stainless steel welding wire.

5. The method of making a duplex stainless steel welding wire according to claim 3, characterized in that, In step S200, the continuous casting comprises: The alloy solution of the duplex stainless steel welding wire is transferred to a continuous casting machine at a temperature of 1475-1485 DEG C, and is continuously cast under the protection of argon; Wherein, the tundish temperature is controlled at 1445-1455 DEG C, the continuous casting speed is controlled at 0.7-0.8 m / min, the submerged entry nozzle depth is 130-140 mm, the thickness of the obtained continuous casting billet is controlled at 220-260 mm, and the width is controlled at 1500-1600 mm.

6. The method of making a duplex stainless steel welding wire according to claim 5, characterized in that, In step S200, the cutting and hot rolling of the wire rod comprises: The continuous casting billet is cut into a square billet with a cross section of (220-260)*(220-260) mm and a length of 1500-1600 mm; The square billet is heated at a temperature of 1250-1270 DEG C for 50-70 min, and then hot rolled into a wire rod with a diameter of Φ5.4-5.6 mm.

7. The method of producing a duplex stainless steel welding wire according to claim 6, characterized in that, In step S200, the drawing comprises: The wire rod with a diameter of Φ5.4-5.6 mm is drawn for 5-7 passes to obtain a wire rod with a diameter of 2-2.5 mm; wherein the deformation rate of each pass is 10-22%; after each drawing before the last drawing, the wire rod is annealed, the annealing temperature is 1050-1110 DEG C, and the holding time is 2-5 min; The wire rod with a diameter of 2-2.5 mm is drawn for 7-12 passes to obtain the duplex stainless steel welding wire with a diameter of 1.15-1.2 mm; wherein the deformation rate of each pass is 7-15%, and the diameter size tolerance of the duplex stainless steel welding wire is ≤0.01 mm.

8. The method of making a duplex stainless steel welding wire according to claim 6, characterized in that, In step S200, after hot rolling of the wire rod, the preparation method further comprises pickling, and the pickling comprises: The wire rod with a diameter of Φ5.4-5.6 mm is held at a temperature of 1050-1100 DEG C for 25-35 min, then cooled to 20-30 DEG C, and then pickled with a mixed solution of 100-120 g / L nitric acid + 40-50 g / L hydrofluoric acid for 55-65 min.

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