A gas shielded high-strength welding wire steel wire rod and a short-process low-phosphorus and low-nitrogen preparation method thereof

Abstract

The present application relates to a kind of gas protection high-strength welding wire steel wire rod and its short process low-phosphorus low-nitrogen preparation method, realize the mass content of phosphorus at the end of electric arc furnace smelting less than 0.005%, the mass content of carbon 0.03~0.07%, the mass content of nitrogen less than 0.005%.The present application utilizes end temperature and composition control of electric furnace smelting process, ensures the composition of molten steel at the end of electric furnace smelting, thereby reduces the risk of long refining time and increasing phosphorus content caused by a large amount of alloy addition in LF refining.Secondly, by improving the slagging, oxygen supply and power supply system of electric furnace smelting process, high-efficiency deep dephosphorization is realized in the smelting process, and the nitrogen absorption caused by power supply is reduced.

Description

Technical Field

[0001] This invention relates to a gas-shielded high-strength welding wire rod and its short-process low-phosphorus and low-nitrogen preparation method, belonging to the technical field of gas-shielded high-strength welding wire production. Background Technology

[0002] High-strength gas-shielded welding wire steel achieves high strength, low-temperature toughness, and corrosion resistance through optimized alloy design, covering the needs of multiple fields from conventional industries to extreme environments. It is widely used in engineering machinery, automobile manufacturing, shipbuilding, and petrochemical industries. Due to the special performance requirements of gas-shielded high-strength welding wire steel, alloying elements such as nickel, chromium, and molybdenum need to be added, while the content of impurity elements such as phosphorus and nitrogen in the steel is subject to high requirements. Traditional high-quality welding wire steel is generally produced using a blast furnace-KR molten iron pretreatment-converter-refining-continuous casting process, which has a long production process and high carbon emissions. For example, patent application CN118848336A provides a gas-shielded welding wire, gas-shielded welding wire steel wire rod, and its production method. This method improves the performance of gas-shielded high-strength welding wire steel by optimizing the alloy composition design and controlling the steelmaking and rolling processes during the long converter production process. In recent years, the use of short-process electric arc furnaces to produce high-quality welding wire steel has gradually increased. For example, patent application CN105063474A discloses an electric arc furnace smelting method for welding wire steel. This method achieves short-process, low-phosphorus smelting of welding wire steel by optimizing the slag formation, temperature, and slag flow regimes of the electric arc furnace. However, currently, high-quality gas-shielded high-strength welding wire steel is mainly produced using a long converter process. While controlling phosphorus and nitrogen in the steel is relatively easy, it suffers from a long production process and high carbon emissions. When using a short-process electric arc furnace, the challenge of controlling impurity elements such as phosphorus and nitrogen arises. Summary of the Invention

[0003] To address the aforementioned problems, this invention discloses a gas-shielded high-strength welding wire rod and its short-process, low-phosphorus, and low-nitrogen preparation method, the specific technical solution of which is as follows:

[0004] A short-process preparation method for gas-shielded high-strength welding wire steel with low phosphorus and low nitrogen content is disclosed, which adopts an electric arc furnace smelting-LF refining-small billet continuous casting-high-speed wire rod rolling process, specifically including the following steps:

[0005] Step 1: Electric arc furnace smelting: Add molten iron, scrap steel and ferronickel into the furnace. Add ferronickel into the scrap steel bale and add it into the furnace together with the scrap steel. Add crushed material to the bottom of the scrap steel bale, add ferronickel to the middle and lower part of the scrap steel bale, add heavy scrap steel to the middle and upper part of the scrap steel bale, and add crushed material to the top of the scrap steel bale.

[0006] Step 2: After the electric arc furnace smelting is completed, the final tapping temperature of the electric arc furnace is greater than 1620℃, the final phosphorus content is less than 0.005%, the final carbon content is 0.03%~0.07%, and the final nitrogen content is less than 0.005%.

[0007] Step 3: When one-third of the steel is tapped from the electric arc furnace, add 900-950 kg of low-titanium and low-aluminum ferrosilicon, 1500-1550 kg of low-carbon ferromanganese, and 300-350 kg of lime; when the steel is tapped from the electric arc furnace, add 700-750 kg of ferromolybdenum to the ladle.

[0008] Step 4: The ladle is hoisted into the LF refining station, and temperature measurement and sampling begin; power is turned on to raise the temperature, and 100~150kg of calcium carbide is added to diffuse and deoxidize the slag; 300~400kg of lime is added, and the bottom blowing argon flow rate is controlled at 600~800NL / min.

[0009] Step 5: Based on the composition results of the molten steel sample, add nickel plate and low-carbon ferrochrome, as well as the remaining low-titanium, low-aluminum ferrosilicon, low-carbon ferromanganese and ferromolybdenum from Step 3 to adjust the composition. The bottom blowing flow rate is controlled at 400~600 NL / min.

[0010] Step 6: After the silicon, manganese, nickel, chromium and molybdenum content in the steel is qualified, feed in 400~450m of titanium wire, and control the bottom blowing flow rate at 150~250 NL / min;

[0011] Step 7: After the composition adjustment is completed, gradually reduce the bottom blowing argon gas in the ladle to a soft stirring state. The argon gas flow rate is 40~100NL / min, so that the slag surface fluctuates slightly. The soft stirring time is 15min~16min.

[0012] Step 8: Casting using a small billet continuous casting machine;

[0013] Step 9: High-speed wire rolling process: The heating temperature is 1120℃~1160℃, the finishing temperature is 930℃~970℃, and the wire drawing temperature is 810℃~850℃.

[0014] Furthermore, the specific process of electric arc furnace smelting in step 1 is as follows:

[0015] Step 1.1: Electric arc furnace smelting. After the molten iron is poured in, the furnace wall lance is turned on for blowing. The total oxygen flow rate of the furnace wall lance is 3500~3600 Nm. 3 / h; After the molten iron is poured in, the oxygen flow rate of the furnace wall lance is controlled at 5400~5500 Nm. 3 / h, the oxygen injection flow rate of the furnace door lance is controlled at 2000~2200 Nm 3 / h;

[0016] Step 1.2: Electric arc furnace smelting, oxygen consumption reaches 800 Nm³.3 Then, the electrodes were lowered and energized, with voltage level 10 and current level 5, controlling the active power to 40~45MW.

[0017] Step 1.3: Electric arc furnace smelting. After the electric arc furnace smelting starts, add 400-500 kg of lime and 400-500 kg of lightly calcined dolomite from the high-level silo. Then add 400-500 kg of lime every 2 minutes.

[0018] Step 1.4: Electric arc furnace smelting. After the scrap steel is melted and cleaned, temperature measurement and sampling begin. Once the molten pool temperature exceeds 1520℃, the oxygen flow rate of the furnace wall lance is controlled at 4200~4300 Nm. 3 / h, the oxygen injection flow rate of the furnace door lance is controlled at 1500~2000 Nm 3 / h; Add 400-500 kg of lime every 2-3 minutes;

[0019] Step 1.5: Electric arc furnace smelting. After the scrap steel is melted and cleaned, the temperature is greater than 1520℃. The voltage setting is controlled at level 8, the current setting is controlled at level 5, and the active power is controlled at 35~40MW.

[0020] Step 1.6: Electric arc furnace smelting. After the scrap steel is melted and cleaned, the furnace wall gun starts to spray carbon powder to ensure that the height of the foam slag at the furnace door is 1 / 2 to 2 / 3 of the furnace door height.

[0021] Furthermore, in step 1, the mass of molten iron fed into the furnace is 70t~75t, the amount of scrap steel added is 30t~35t, and the amount of nickel-iron added is 11t~13t;

[0022] Add 8-10 tons of crushed material to the bottom of the scrap steel bale, with a bulk density controlled at 0.8-1.0; add 11-13 tons of nickel-iron to the lower part of the scrap steel bale; add 10-13 tons of heavy scrap steel to the upper part of the scrap steel bale, with a bulk density controlled at 1.3-1.5; add 10-12 tons of crushed material to the top of the scrap steel bale, with a bulk density controlled at 0.6-0.8.

[0023] The thickness of the scrap steel entering the furnace is ≥3.0mm, and the mass content of S in the scrap steel is ≤0.025%, Cu is ≤0.05%, and Al is ≤0.03%; the temperature of the molten iron is >1350℃, and the mass content of S in the molten iron is <0.005% and the mass content of P is <0.09%.

[0024] Furthermore, in the electric arc furnace smelting process of step 1, the mass content of some elements in the nickel-iron fed into the furnace is 8%≤Ni≤12%, P≤0.06%, S≤0.5%, C≤4.0%, and Si≤5.0%.

[0025] Furthermore, the lime addition during the electric arc furnace smelting process is controlled at 50~55 kg / t, and the power consumption is controlled at 70~90 kWh / t.

[0026] Furthermore, in the electric arc furnace smelting process, the slag basicity before scrap steel melting and cleaning is controlled at 1.8~2.3, and the slag basicity after melting and cleaning is controlled at 3.5~4.0.

[0027] Furthermore, during the electric arc furnace smelting process, the carbon powder injection flow rate of the furnace wall gun is controlled at 60~70 kg / min, and the carbon powder consumption is controlled at 10~12 kg / t.

[0028] Furthermore, step 8 specifically involves: blowing argon into the tundish for more than 5 minutes before pouring, inserting the submersible nozzle to a depth of 90-140 mm, ensuring that the submersible nozzle is aligned and that the deviation from the center line of the crystallizer copper tube is less than 5 mm.

[0029] Use low-carbon steel protective slag with small square billets, and control the thickness of the protective slag liquid layer to 8~10mm;

[0030] Control the superheat of molten steel in the tundish to 30℃~50℃;

[0031] Use electromagnetic stirring in the crystallizer. The electromagnetic stirring current of the crystallizer is 300~400A, the frequency is 4~6Hz, and the water flow rate of the crystallizer is controlled at 1725±25L / min.

[0032] Furthermore, the continuous casting machine is a straight arc type continuous casting machine, and the cross-sectional dimensions of the continuously cast billet are 140mm×140mm;

[0033] The continuous casting tundish has a casting capacity of ≥20t at the start of casting, a tundish tonnage of ≥35t during normal casting, and a tundish tonnage of ≥38t during continuous casting and ladle changing.

[0034] During the continuous casting process, the argon sealing pressure of the ladle nozzle is 0.2~0.3MPa, and the casting speed of the billet is controlled at 2.4~2.6m / min.

[0035] A gas-shielded high-strength welding wire steel rod is obtained by the above-mentioned short-process low-phosphorus and low-nitrogen preparation method of gas-shielded high-strength welding wire steel;

[0036] In terms of mass percentage, the gas-shielded high-strength welding wire steel, excluding Fe element and unavoidable impurities, also includes the following chemical composition in mass percentage: C: 0.08%~0.1%, Si: 0.55%~0.66%, Mn: 1.65%~1.80%, Cr: 0.15%~0.25%, Mo: 0.45%~0.55%, Ni: 1.45%~1.55%, V≤0.02%, Al≤0.008%, S: 0.008%~0.016%, P≤0.01%.

[0037] The working principle of this invention is:

[0038] Due to the special performance requirements of high-quality gas-shielded welding wire steel, alloying elements such as nickel, chromium, and molybdenum are typically added, while the content of impurities such as phosphorus and nitrogen in the steel is subject to high requirements. Currently, high-quality gas-shielded welding wire steel is mainly produced using a converter long-process, which makes it relatively easy to control phosphorus and nitrogen in the steel, but it suffers from long production processes and high carbon emissions. When using an electric arc furnace short-process, the control of impurities such as phosphorus and nitrogen presents a challenge. This invention systematically improves the production process of gas-shielded welding wire steel by using an electric arc furnace—LF refining—small billet continuous casting—high-speed wire rod rolling process. The key points of the entire process are as follows:

[0039] (1) In view of the problem that the high content of alloy elements in gas shielded welding wire steel leads to the difficulty in controlling the phosphorus content and the excessive refining time caused by adding a large amount of alloy at the LF refining station during conventional production, some non-oxidizing alloys are added to the furnace along with scrap steel in the form of raw materials in the electric furnace process. This fully utilizes the advantages of precise temperature control and efficient dephosphorization when the electric furnace is powered on and heated, thus solving the problem of difficulty in controlling the phosphorus content and long refining time caused by the large amount of alloy added to high-quality welding wire steel, while reducing the cost of alloys.

[0040] (2) In the electric arc furnace smelting process, in order to improve the dephosphorization effect, before the scrap steel is melted and cleaned, the oxygen flow rate of the furnace wall gun and the flow rate of the furnace door gun are controlled. The impact of the oxygen jet on the molten pool and the stirring effect of the gas generated by the decarburization reaction are used to accelerate the mass transfer of phosphorus to the steel slag interface. At the same time, the amount and frequency of lime addition are controlled to accelerate the lime melting into slag and control the slag basicity at 1.8-2.3 to achieve rapid dephosphorization. After the scrap steel is melted and cleaned, the power supply voltage and current level are controlled to slow down the heating rate of the molten steel and prevent the molten pool stirring effect from deteriorating due to power outages. Furthermore, the amount and frequency of lime addition are optimized to control the slag basicity at 3.5-4.0 to achieve enhanced dephosphorization in the later stage of smelting.

[0041] (3) In the electric arc furnace smelting process, after the scrap steel is melted and cleaned, in order to control the amount of nitrogen absorbed by the molten steel, a continuous carbon powder spraying process is adopted on the furnace wall. By optimizing the amount of carbon powder sprayed, continuous and good foam slag is ensured. The height of the foam slag covers 1 / 2 to 2 / 3 of the furnace door. At the same time, the voltage and current settings are optimized to reduce the arc length, thereby achieving good arc coverage and reducing the amount of nitrogen absorbed by the molten steel.

[0042] (4) In the early stage of the refining process, the composition is quickly adjusted, and appropriate amounts of calcium carbide and lime are added to control the oxidizing properties and alkalinity of the slag. After the composition adjustment is completed, the bottom blowing argon gas is adjusted to perform soft stirring to promote the floating and removal of inclusions.

[0043] The beneficial effects of this invention are:

[0044] This invention improves the production process of high-quality welding wire steel by systematically refining the process. Leveraging the precise control of temperature and composition at the end of the electric arc furnace (EAF) smelting process, it optimizes the addition of scrap steel, molten iron, and alloys to the furnace feed, ensuring the optimal steel composition at the EAF smelting endpoint. This reduces the risks of excessively long refining times and increased phosphorus content caused by the addition of large amounts of alloys during LF refining. Secondly, by improving the slag formation, oxygen supply, and power supply systems in the EAF smelting process, it achieves efficient and deep dephosphorization, reducing nitrogen intake during energization. Further control of the refining, continuous casting, and rolling processes yields high-quality welding wire steel wire rods. The weld metal obtained from the weld metal deposition test using the aforementioned welding wire exhibits a tensile strength ≥800MPa and a low-temperature impact energy ≥110J at -40℃. Detailed Implementation

[0045] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0046] The following are two specific examples of the application of this invention:

[0047] In electric arc furnace smelting, a method of adding one ladle of molten iron and one ladle of scrap steel is adopted. The scrap steel is added into the furnace from the ladle, and the molten iron is added into the furnace from the molten iron chute at the back of the furnace. The specific amount of scrap steel added is shown in Table 1:

[0048] Table 1

[0049]

[0050] The scrap steel fed into the furnace should have an S content ≤0.025%, Cu content ≤0.05%, and Al content ≤0.03%, with a thickness ≥3.0mm. After the scrap steel is added, molten iron is added, and the oxygen lances on the furnace wall are turned on for blowing. The total flow rate of the oxygen lances is controlled at 3500-3600 Nm. 3 / h. After the molten iron is fully poured in, the flow rate of the furnace wall lance is controlled at 5400-5500 Nm. 3 / h, furnace door gun flow rate controlled at 2000-2200 Nm 3 / h. Simultaneously, 400 kg of lime and 500 kg of lightly calcined lime are added from the high-level silo, followed by 400 kg of lime every 2 minutes thereafter. Oxygen consumption reaches 800 Nm³. 3 Afterwards, the electrodes were lowered and energized, with voltage setting 10 and current setting 5. After the scrap steel was melted and cleared, temperature measurement and sampling began. Once the molten pool temperature exceeded 1520℃, the flow rate of the furnace wall gun was controlled at 4200-4300 Nm³. 3 / h, the flow rate of the furnace door gun is controlled at 1500-2000 Nm 3 / h. Add 400kg of lime every 2-3 minutes. Control the voltage setting at level 8 and the current setting at level 5. Begin injecting carbon powder into the furnace wall lance, maintaining a carbon powder flow rate of 60-70kg / min. The tapping temperature of the electric arc furnace and the final carbon, phosphorus, and nitrogen contents are shown in Table 2.

[0051] Table 2

[0052]

[0053] When one-third of the steel has been tapped from the electric arc furnace, low-titanium, low-aluminum ferrosilicon, low-carbon ferromanganese, and lime are added. At the end of the tapping process, ferromolybdenum is added to the ladle, as shown in Table 3.

[0054] Table 3

[0055]

[0056] The ladle is hoisted into the LF refining station and energized for heating. Calcium carbide is added to diffuse and deoxidize the slag. Lime is added to control the slag alkalinity and the bottom-blown argon flow rate, as shown in Table 4.

[0057] Table 4

[0058]

[0059] Temperature sampling was performed, and based on the required steel composition, the remaining low-titanium, low-aluminum ferrosilicon, low-carbon ferromanganese, nickel plate, ferromolybdenum, and low-carbon ferrochrome were added. After composition adjustment, titanium wire was fed in, and the temperature of the molten steel was controlled within a suitable range. Soft stirring was used to remove inclusions, and the bottom-blowing argon gas in the ladle was gradually reduced to a soft stirring state, with the stirring time controlled.

[0060] Table 5

[0061]

[0062] The next step is the continuous casting process, with the billet cross-section measuring 140mm × 140mm. The initial casting tonnage in the tundish is set at 20t, the normal casting tonnage at 35t, and the tundish tonnage at 38t during continuous casting and ladle changing. The superheat of the molten steel in the tundish is controlled at 40℃, and the casting speed is controlled at 2.5m / min. The thickness of the protective slag layer in the crystallizer, the argon seal pressure at the long nozzle, the electromagnetic current of the crystallizer, the crystallizer frequency, and the crystallizer water flow rate are shown in Table 6.

[0063] Table 6

[0064]

[0065] The rolling heating temperature, finishing rolling temperature, and wire drawing temperature settings in the rolling process are shown in Table 7.

[0066] Table 7

[0067]

[0068] The elemental contents of the final gas-shielded high-strength welding wire rod are shown in Table 8 below:

[0069] Table 8

[0070]

[0071] Table 8 shows the elemental limitations for high-quality welding wire rods.

[0072] The properties of the weld metal obtained from the weld metal tests conducted on the welding wires obtained in Examples 1 and 2 are shown in Table 9:

[0073] Table 9

[0074]

[0075] As can be seen from Table 9, the welding wires of Examples 1 and 2 meet the requirements of high-quality welding wire steel rods.

[0076] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0077] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing high-strength welding wire steel with short-process low-phosphorus and low-nitrogen gas insulation, characterized in that, The production process employs electric arc furnace smelting - LF refining - small billet continuous casting - high-speed wire rod rolling, specifically including the following steps: Step 1: Electric arc furnace smelting: Add molten iron, scrap steel and ferronickel into the furnace. Add ferronickel into the scrap steel bale and add it into the furnace together with the scrap steel. Add crushed material to the bottom of the scrap steel bale, add ferronickel to the middle and lower part of the scrap steel bale, add heavy scrap steel to the middle and upper part of the scrap steel bale, and add crushed material to the top of the scrap steel bale. After the molten iron is poured in, the oxygen flow rate of the furnace wall lance is controlled at 5400~5500 Nm. 3 / h, the oxygen injection flow rate of the furnace door lance is controlled at 2000~2200 Nm 3 / h; After the scrap steel is melted and cleaned, temperature measurement and sampling begin. Once the molten pool temperature exceeds 1520℃, the oxygen flow rate of the furnace wall lance is controlled at 4200~4300 Nm. 3 / h, the oxygen injection flow rate of the furnace door lance is controlled at 1500~2000 Nm 3 / h; Add 400-500 kg of lime every 2-3 minutes; The slag basicity in the electric arc furnace smelting process is controlled at 1.8~2.3 before the scrap steel is melted and cleaned, and at 3.5~4.0 after the scrap steel is melted and cleaned. During the electric arc furnace smelting process, the carbon powder injection flow rate of the furnace wall gun is controlled at 60~70kg / min, and the carbon powder consumption is controlled at 10~12kg / t; Step 2: After the electric arc furnace smelting is completed, the final tapping temperature of the electric arc furnace is greater than 1620℃, the final phosphorus content is less than 0.005%, the final carbon content is 0.03%~0.07%, and the final nitrogen content is less than 0.005%. Step 3: When one-third of the steel is tapped from the electric arc furnace, add 900-950 kg of low-titanium and low-aluminum ferrosilicon, 1500-1550 kg of low-carbon ferromanganese, and 300-350 kg of lime; when the steel is tapped from the electric arc furnace, add 700-750 kg of ferromolybdenum to the ladle. Step 4: The ladle is hoisted into the LF refining station, and temperature measurement and sampling begin; power is turned on to raise the temperature, and 100~150kg of calcium carbide is added to diffuse and deoxidize the slag; 300~400kg of lime is added, and the bottom blowing argon flow rate is controlled at 600~800NL / min. Step 5: Based on the composition results of the molten steel sample, add nickel plate and low-carbon ferrochrome, as well as the remaining low-titanium, low-aluminum ferrosilicon, low-carbon ferromanganese and ferromolybdenum from Step 3 to adjust the composition. The bottom blowing flow rate is controlled at 400~600 NL / min. Step 6: After the silicon, manganese, nickel, chromium and molybdenum content in the steel is qualified, feed in 400~450m of titanium wire, and control the bottom blowing flow rate at 150~250 NL / min; Step 7: After the composition adjustment is completed, gradually reduce the bottom blowing argon gas in the ladle to a soft stirring state. The argon gas flow rate is 40~100NL / min, so that the slag surface fluctuates slightly. The soft stirring time is 15min~16min. Step 8: Casting using a small billet continuous casting machine; Step 9: High-speed wire rod rolling process: The heating temperature is 1120℃~1160℃, the finishing temperature is 930℃~970℃, and the wire drawing temperature is 810℃~850℃. The product composition, excluding Fe and unavoidable impurities, includes the following chemical components by mass percentage: C: 0.08%~0.1%, Si: 0.55%~0.66%, Mn: 1.65%~1.80%, Cr: 0.15%~0.25%, Mo: 0.45%~0.55%, Ni: 1.45%~1.55%, V≤0.02%, Al≤0.008%, S: 0.008%~0.016%, P≤0.01%.

2. The method for preparing short-process, low-phosphorus, low-nitrogen, high-strength welding wire steel according to claim 1, characterized in that, The specific process of electric arc furnace smelting in step 1 is as follows: Step 1.1: Electric arc furnace smelting. After the molten iron is poured in, the furnace wall lance is turned on for blowing. The total oxygen flow rate of the furnace wall lance is 3500~3600 Nm. 3 / h; Step 1.2: Electric arc furnace smelting, oxygen consumption reaches 800 Nm³. 3 Then, the electrodes were lowered and energized, with voltage level 10 and current level 5, controlling the active power to 40~45MW. Step 1.3: Electric arc furnace smelting. During the electric arc furnace smelting process, the amount of lime added is controlled at 50~55kg / t. After the electric arc furnace smelting starts, add 400~500kg of lime and 400~500kg of lightly calcined dolomite from the high-level silo. Thereafter, add 400~500kg of lime every 2 minutes. Step 1.4: Electric arc furnace smelting. After the scrap steel is melted and cleaned, the temperature is greater than 1520℃. The voltage setting is controlled at level 8, the current setting is controlled at level 5, and the active power is controlled at 35~40MW. Step 1.5: Electric arc furnace smelting. After the scrap steel is melted and cleaned, the furnace wall gun starts to spray carbon powder to ensure that the height of the foam slag at the furnace door is 1 / 2 to 2 / 3 of the furnace door height.

3. The method for preparing short-process, low-phosphorus, low-nitrogen, high-strength welding wire steel according to claim 1, characterized in that, In step 1, the mass of molten iron fed into the furnace is 70t~75t, the amount of scrap steel added is 30t~35t, and the amount of nickel-iron added is 11t~13t; Add 8-10 tons of crushed material to the bottom of the scrap steel bale, with a bulk density controlled at 0.8-1.0; add 11-13 tons of nickel-iron to the lower part of the scrap steel bale; add 10-13 tons of heavy scrap steel to the upper part of the scrap steel bale, with a bulk density controlled at 1.3-1.5; add 10-12 tons of crushed material to the top of the scrap steel bale, with a bulk density controlled at 0.6-0.

8. The thickness of the scrap steel entering the furnace is ≥3.0mm, and the mass content of S in the scrap steel is ≤0.025%, Cu is ≤0.05%, and Al is ≤0.03%; the temperature of the molten iron is >1350℃, and the mass content of S in the molten iron is <0.005% and the mass content of P is <0.09%.

4. The method for preparing short-process, low-phosphorus, low-nitrogen, high-strength welding wire steel according to claim 1, characterized in that, In the electric arc furnace smelting process of step 1, the mass content of some elements in the nickel-iron fed into the furnace is 8%≤Ni≤12%, P≤0.06%, S≤0.5%, C≤4.0%, and Si≤5.0%.

5. The method for preparing short-process, low-phosphorus, low-nitrogen, high-strength welding wire steel according to claim 1, characterized in that, The power consumption of the electric arc furnace smelting process is controlled at 70~90kWh / t.

6. The method for preparing short-process, low-phosphorus, low-nitrogen, high-strength welding wire steel according to claim 1, characterized in that, Step 8 specifically involves: blowing argon into the tundish for more than 5 minutes before pouring, inserting the submersible nozzle to a depth of 90-140 mm, ensuring that the submersible nozzle is aligned and that the deviation from the center line of the crystallizer copper tube is less than 5 mm. Use low-carbon steel protective slag with small square billets, and control the thickness of the protective slag liquid layer to 8~10mm; Control the superheat of molten steel in the tundish to 30℃~50℃; Use electromagnetic stirring in the crystallizer. The electromagnetic stirring current of the crystallizer is 300~400A, the frequency is 4~6Hz, and the water flow rate of the crystallizer is controlled at 1725±25L / min.

7. The method for preparing short-process, low-phosphorus, low-nitrogen, high-strength welding wire steel according to claim 1, characterized in that, The continuous casting machine is a straight arc type continuous casting machine, and the cross-sectional dimensions of the continuously cast billet are 140mm×140mm. The initial casting capacity of the tundish during continuous casting is ≥20t, the tundish capacity during normal casting is ≥35t, and the tundish capacity during continuous casting and ladle changing is ≥38t. During continuous casting, the argon seal pressure of the ladle nozzle is 0.2~0.3MPa, and the casting speed of the billet is controlled at 2.4~2.6m / min.

8. A gas-shielded high-strength welding wire rod, characterized in that, It is obtained by the preparation method of short-process low-phosphorus and low-nitrogen gas-insulated high-strength welding wire steel as described in any one of claims 1 to 7.

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