Wire rod for low-aluminum low-calcium sulfur-control gas shield welding wire and production method of wire rod

Abstract

The invention relates to a wire rod for a low-aluminum low-calcium sulfur-controlled gas shielded welding wire and a production method of the wire rod. The wire rod comprises the following chemical components in percentage by mass: 0.080-0.110% of C, 0.80-1.10% of Si, 1.60-1.80% of Mn, less than or equal to 0.020% of P, 0.006-0.018% of S, less than or equal to 0.0010% of Ca, less than or equal to 0.015% of Al, less than or equal to 0.15% of Cr, less than or equal to 0.15% of Ni, less than or equal to 0.20% of Cu and the balance of Fe and unavoidable impurities. According to the wire rod for the G4Si1 gas shielded welding wire, the component design of low aluminum, low calcium and sulfur control is adopted, the production technology of controlled rolling and controlled cooling and heat preservation channel slow cooling is matched, the produced wire rod for the G4Si1 gas shielded welding wire can meet the mechanical property, the drawing property, the welding property and the use requirements of users, and the G4Si1 gas shielded welding wire is little in splashing and few in pore defect when used.

Description

Technical Field

[0001] The present invention relates to the technical field of wire rod production, and in particular to a wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire used for manufacturing G4Si1 welding wire and a production method thereof. Background Art

[0002] Gas Metal Arc Welding (GMAW) wire is the filler metal used in MIG / MAG welding. The arc melts the wire and the base metal to form a weld. GMAW wire is categorized by material type, including carbon steel and low-alloy steel wire, stainless steel wire, aluminum and aluminum alloy wire, and nickel-based alloy wire.

[0003] G4Si1 welding wire is a common welding wire for metallurgical gas shielded welding. It belongs to the silicon-manganese alloy system and is suitable for welding low-carbon steel and low-alloy steel such as Q235 and Q345 (16Mn). It has good welding performance and mechanical properties and is widely used in steel structures, automobile manufacturing, engineering machinery, bridges, pressure vessel manufacturing and other industries.

[0004] G4Si1 gas shielded welding wire is mainly used for welding high-quality carbon steel and low-alloy high-strength steel. The tensile strength of the weld metal is required to reach above 500MPa and it has good toughness. At the same time, the wire has the advantages of less spatter, stable arc and good weld formability during welding.

[0005] At present, there are still some problems in the practical application of gas shielded welding wire, such as serious metal particle splashing during welding, which is not only related to the proportion of shielding gas and welding parameters, but also directly related to the composition of the welding wire; another example is pores (including hydrogen pores and nitrogen pores) and slag inclusions. If the aluminum content in the molten steel used to make wire rods is too high, it is easy to react with oxygen in the air to form Al2O3, which is easy to produce flocculence during continuous casting. During welding, the manufactured welding wire has a strong affinity with Al and O, which causes the oxygen partial pressure in the welding molten pool to decrease and the hydrogen partial pressure to increase, resulting in the generation of hydrogen pores. Summary of the Invention

[0006] The present invention provides a wire rod for low-aluminum, low-calcium, controlled-sulfur gas shielded welding wire and a production method thereof. The wire rod adopts a "low-aluminum, low-calcium, controlled-sulfur" component design and is combined with a "controlled rolling and controlled cooling + slow cooling in an insulation channel" production process. The produced wire rod for G4Si1 gas shielded welding wire can meet the mechanical properties, drawing properties, welding properties and user requirements. The G4Si1 gas shielded welding wire has less spatter and fewer porosity defects during use.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A wire rod for low-aluminum, low-calcium sulfur-controlled gas shielded welding wire. The chemical composition of the wire rod is, by mass percentage, C: 0.080%-0.110%, Si: 0.80%-1.10%, Mn: 1.60%-1.80%, P≤0.020%, S: 0.006%-0.018%, Ca≤0.0010%, Al≤0.015%, Cr≤0.15%, Ni≤0.15%, Cu≤0.20%, and the remainder is Fe and unavoidable impurities.

[0009] The finished product structure of the wire rod is ferrite + pearlite structure, and by volume ratio, ferrite accounts for 85% to 90% and pearlite accounts for 10% to 15%.

[0010] The finished product properties of wire rod are: tensile strength 530~560MPa, elongation after fracture 28%~33%, and cross-sectional shrinkage 74%~81%.

[0011] A method for producing wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire comprises the following steps:

[0012] 1) KR hot metal pretreatment: spray desulfurizer into the hot metal ladle for desulfurization. After pretreatment, the sulfur content in the hot metal is ≤0.005%, and the slag is cleaned;

[0013] 2) Converter smelting: Use top-bottom combined blowing converter for smelting, top blowing oxygen purity> 99.6%, oxygen pressure of 1.1-1.3MPa; combined blowing supplies argon, argon pressure of 1.1-1.3MPa; tapping temperature is 1595-1650℃, tapping end point C≤0.05% and P≤0.012% by mass percentage, slag is strictly prohibited, and spot blowing is avoided;

[0014] 3) Ladle alloying: Alloying is carried out 2 minutes after steel tapping, with argon blowing time ≥ 5 minutes; active lime 27.02-27.76 kg / t steel, dolomite 10.2-10.8 kg / t steel; and silicon manganese alloy 24.5-25.5 kg / t steel.

[0015] 4) Static argon blowing: argon blowing time ≥ 5min; the temperature of the molten steel after treatment is 1560℃~1570℃;

[0016] 5) LF furnace refining: The furnace is maintained at a slightly positive pressure of 40-70 kPa, using submerged arc heating to prevent arc light leakage; 5.3-5.6 kg / t of active lime, 0.80-1.20 kg / t of fluorite, 0.45-0.50 kg / t of carbide slag, and 0.30-0.34 kg / t of ferrosilicon powder are added; reducing slag is produced with a basicity of R = CaO / SiO2 = 1.0-1.5; after deoxidation, silicon and manganese are fine-tuned by adding 4.65-5.35 kg / t of low-aluminum ferrosilicon, 2.5-3.5 kg / t of medium-carbon ferromanganese, and 0.2-0.3 kg / t of recarburizer; soft blowing time ≥ 15 min; LF furnace temperature at the exit is 1575°C-1590°C.

[0017] 6) Continuous casting: adopt the whole process protection casting process, clean the tundish with argon before casting, and the purge time is ≥2min; the crystallizer electromagnetic stirring adopts continuous stirring mode, the electromagnetic stirring current is 230~270A, the frequency is 2~4Hz, and the end electromagnetic stirring adopts forward and reverse alternating stirring mode, the electromagnetic stirring current is 300~340A, and the frequency is 6~10Hz; low-carbon or carbon-free covering agent is used for the tundish, and calcium wire is prohibited; the crystallizer protection slag uses square billet low-carbon protection slag; the platform ladle temperature is 1573±5℃, the tundish temperature is 1530℃~1550℃, the superheat is maintained at 25℃~35℃, the pulling speed is 2.0~2.4m / min, and the pulling speed is constant; the billet is put into the holding pit for slow cooling for more than 48 hours after it comes off the line;

[0018] 7) Heating: Use a walking beam heating furnace for heating, with the preheating section temperature at 880±20℃, the heating section temperature at 1100±20℃, the soaking section temperature at 1110±20℃, and the total heating time at 1.5 to 2.5 hours;

[0019] 8) Rolling, spinning and cooling: Rough rolling temperature is 980±20℃; finishing rolling inlet temperature is 900±20℃; feed and sizing unit temperature is 880±20℃; spinning temperature is 880±20℃; air cooling roller speed: head roller speed is 0.15~0.20m / s, roller speed increase is set to increase by 2%~5%; insulation cover is closed in the first half and opened in the second half; fans are completely turned off; the opening of the Jialing device is 20%~30% throughout the process;

[0020] 9) Slow cooling in the insulation channel: The rolled wire rod is slowly cooled in the insulation channel on the Stelmor slow cooling line, and the temperature of the insulation channel is ≥60℃.

[0021] In the step 1), during converter smelting, the molten iron accounts for 85% to 88% by weight, and the scrap steel accounts for 12% to 15% by weight.

[0022] In the step 3), low-aluminum ferrosilicon and low-carbon ferromanganese are used for alloying treatment.

[0023] In the step 4), when blowing argon, first blow vigorously for 2 to 3 minutes, then blow weakly; the flow rate of strong blowing argon is 780 to 820m 3 / h, weak blowing argon gas flow rate is 95~105m 3 / h.

[0024] In the step 5), the low-aluminum ferrosilicon added is FeSi75Al0.5-A, and in terms of mass percentage, the aluminum content in FeSi75Al0.5-A is less than 0.5%, and the calcium content is less than 1%.

[0025] The typical production process route is: blast furnace molten iron → KR desulfurization pretreatment → 100t converter smelting → LF furnace refining → 150mm×150mm eight-strand square billet continuous casting → heating in regenerative walking beam heating furnace → high-pressure water descaling → rough rolling → intermediate rolling → pre-finishing rolling → finishing rolling → sizing → wire laying → air cooling → coiling → slow cooling in Stelmor slow cooling line insulation channel.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) The "low aluminum, low calcium and controlled sulfur" composition design is adopted, and the production process of "controlled rolling and controlled cooling + slow cooling in an insulation channel" is used. The produced G4Si1 gas shielded welding wire wire rod can meet the mechanical properties, drawing properties, welding properties and user requirements. G4Si1 gas shielded welding wire has less spatter and fewer porosity defects during use.

[0028] 2) The refining process adopts a process different from conventional refining, fully considering the effects of reducing slag basicity, slag amount, reducing atmosphere, and argon blowing and stirring on desulfurization, accurately controlling the S content in molten steel. Under the premise of ensuring that O in steel is ≤50ppm, the S content is controlled within the range of 0.006% to 0.018%, meeting the user's strict requirements for the S content of wire rod and ensuring that the welding wire products can meet the welding performance requirements of end users.

[0029] 3) To reduce spatter generated by the welding wire during welding, the present invention controls the calcium content throughout the steelmaking process. By analyzing the source of calcium in the molten steel, it is required that the use of materials with high aluminum and calcium contents for deoxidation, slagging, and alloying during converter tapping and LF furnace refining is strictly prohibited. For example, low-aluminum ferrosilicon FeSi75Al0.5-A (with an aluminum content of <0.5% and a calcium content of <1%) is used instead of ordinary ferrosilicon (with no aluminum or calcium content requirements) for alloying. No calcium treatment is performed in the LF refining furnace.

[0030] 4) When making white slag in the LF furnace, ferrosilicon powder is used for deoxidation to avoid the use of aluminum-containing deoxidizers to increase Al2O3 inclusions in the steel, ensuring that the Al content in the wire rod steel for G4Si1 welding wire is controlled within 0.010%; Al2O3 and other inclusions in the molten steel are effectively controlled, improving the castability of the molten steel.

[0031] 5) A combination of "Stelmor controlled rolling and controlled cooling process + PF line slow cooling process" is adopted (PF line is the key equipment in the finishing operation area of ​​the high-speed wire production line and an important link in the steel rolling production line. It is mainly used for collecting the wire coils on the coiler. The coil turner turns the coils from upright to flat, and the coil transport trolley transports the loose coils out and hangs them on the C-hook in the waiting position. The temperature of the loose coils slowly drops when passing through the cooling area of ​​the PF line during operation. The cooling area is equipped with inspection, head and tail cutting, and sampling operation stations. When the carrying trolley for hanging loose coils passes through the cooling area, appearance inspection, size inspection and trimming procedures are carried out on each coil, and batch sampling inspection is carried out). The metallographic structure of the wire rod is strictly controlled, and the tensile strength of the wire rod is less than 560MPa, which is convenient for downstream users to carry out drawing production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a metallographic photograph of the wire rod for the low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire described in the present invention. DETAILED DESCRIPTION

[0033] The low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire wire described in the present invention has the following chemical compositions by mass: C: 0.080% to 0.110%, Si: 0.80% to 1.10%, Mn: 1.60% to 1.80%, P ≤ 0.020%, S: 0.006% to 0.018%, Ca ≤ 0.0010%, Al ≤ 0.015%, Cr ≤ 0.15%, Ni ≤ 0.15%, Cu ≤ 0.20%, and the remainder is Fe and unavoidable impurities. The reasons for the composition design are as follows:

[0034] C: Although C can improve the yield strength and tensile strength of the weld, it is detrimental to toughness and increases the metal cold cracking sensitivity of the weld. In the present invention, the C content is controlled within a range of 0.080% to 0.110%.

[0035] Mn and Si: The alloying elements Mn and Si are important strengthening elements for steel. Their strengthening effects primarily come from solid solution strengthening and structural strengthening. Furthermore, during welding, Mn and Si serve as important deoxidizers in the weld pool, preventing pores in the weld and suppressing spatter during welding. If the added Mn and Si contents are properly matched (e.g., an Mn / Si ratio of 3 to 6), the inclusion content in the weld can also be reduced, maintaining a higher level of strength and toughness. Therefore, the present invention controls Si to 0.80% to 1.10% and Mn to 1.60% to 1.80%.

[0036] P: P can strengthen the weld metal, but it is not good for the low temperature toughness of the steel. Therefore, the present invention controls the P content to below 0.020%.

[0037] S: S is a harmful element. Controlling its content can improve the purity of the weld and the welding performance of the welding wire. The present invention controls S: 0.006% to 0.018%.

[0038] Ca: By controlling the Ca content, spatter during welding can be prevented. The present invention controls Ca to ≤ 0.0010%.

[0039] Al: Excessive aluminum content in molten steel easily reacts with oxygen in the air to form Al2O3, which can cause flocculence during continuous casting. During welding, Al has a strong affinity for oxygen, which reduces the oxygen partial pressure and increases the hydrogen partial pressure in the weld pool, thereby generating hydrogen pores. In this invention, aluminum is strictly controlled as a harmful element, requiring Al ≤ 0.015%.

[0040] The present invention discloses a method for producing wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire, and a typical production process route is: blast furnace molten iron → KR desulfurization pretreatment → 100t converter smelting → LF furnace refining → 150mm×150mm eight-strand square billet continuous casting → heating in a regenerative walking beam heating furnace → high-pressure water descaling → rough rolling → intermediate rolling → pre-finishing rolling → finishing rolling → sizing → wire laying → air cooling → coiling → slow cooling in a Stelmor slow cooling line insulation channel.

[0041] It should be emphasized that it is strictly prohibited to use aluminum-containing ladles or calcium-treated ladles during the steelmaking process; it is strictly prohibited to use materials with high aluminum and calcium content for deoxidation, slagging, alloying and other treatments.

[0042] The production method of the low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire according to the present invention comprises the following specific steps:

[0043] 1. KR molten iron pretreatment: spray desulfurizer (preferably 90% lime powder + 10% fluorite powder) into the molten iron ladle for desulfurization. After treatment, the sulfur content in the molten iron is required to be ≤0.005%, and the slag is clean.

[0044] 2. Converter Smelting: Optimally, the molten iron weight ratio is 85% to 88% and the scrap weight ratio is 12% to 15%. Use a top- and bottom-blown converter for smelting. Top-blown oxygen purity should be >99.6% and the oxygen pressure should be 1.1-1.3 MPa. Combined blowing should include argon at a pressure of 1.1-1.3 MPa. The tapping temperature should be 1595-1650°C, with the tapping endpoint C ≤ 0.05% and P ≤ 0.012%. Slag addition is strictly prohibited, and spot blowing is avoided. Ensure that the endpoint carbon content and temperature are achieved within a single step. If double spot blowing occurs, perform a hood lowering process first, and adopt a circular flow tapping method to avoid nitrogen absorption.

[0045] 3. Ladle Alloying: 2 minutes after tapping, alloying is performed using low-aluminum ferrosilicon and low-carbon ferromanganese. Argon blowing is performed for ≥5 minutes. Auxiliary materials include 27.02-27.76 kg / t of steel of active lime and 10.2-10.8 kg / t of steel of dolomite. The target alloying amount is 24.5-25.5 kg / t of steel of high-silicon ferrosilicon and manganese.

[0046] 4. Quiet argon blowing: The blowing time is ≥5 minutes, first strong blowing for 3 minutes, then weak blowing; the strong blowing argon flow rate is 780~820m 3 / h, weak blowing argon gas flow rate is 95~105m 3 / h. The temperature of the molten steel after treatment is 1560℃~1570℃.

[0047] 5. LF Furnace Refining: Maintain a slightly positive pressure (40-70 kPa) within the furnace, using submerged arc heating to prevent arc light leakage. Add 5.3-5.6 kg / t of active lime, 0.80-1.20 kg / t of fluorite, 0.45-0.50 kg / t of carbide slag, and 0.30-0.34 kg / t of ferrosilicon powder. Active lime should be added evenly in batches during the early stages of refining; adding it later is strictly prohibited. Ferrosilicon powder and carbide are used for diffusion deoxidation in the slag to produce a reducing slag (basicity R = CaO / SiO2 = 1.0-1.5). Fine-tuning of silicon and manganese is performed after deoxidation is complete. Add 4.65-5.35 kg / t of low-aluminum ferrosilicon (preferably FeSi75Al0.5-A, with an aluminum content of less than 0.5% and a calcium content of less than 1%), 2.5-3.5 kg / t of medium-carbon ferromanganese, and 0.2-0.3 kg / t of recarburizer (preferably petroleum coke recarburizer) to the steel. If sulfur is low during the process, sulfur adjustment is performed using a sulfur-iron wire after power is turned off. The soft-blowing time should be ≥ 15 minutes. The LF furnace's off-site temperature should be 1575°C-1590°C.

[0048] 6. Continuous Casting: To ensure ingot quality, measures such as controlling molten steel superheat and casting speed, as well as electromagnetic stirring in the continuous casting mold and at the end of the casting process, are employed to avoid defects such as carbon center segregation, center porosity, or shrinkage cavities. A fully protected casting process is implemented. Before casting begins, the tundish is purged with argon for ≥2 minutes. The mold electromagnetic stirring current is 230-270A, with a frequency of 2-4Hz, for continuous stirring. The end of the casting process uses electromagnetic stirring at a current of 300-340A, at a frequency of 6-10Hz, with alternating forward and reverse rotations (preferably with an interval of 8-3-8 seconds). A low-carbon or carbon-free covering agent is used in the tundish, and calcium wire is prohibited. Low-carbon mold slag for square billets is used as the mold slag. The platform ladle temperature is 1573±5°C, the tundish temperature is 1530-1550°C, the superheat is maintained at 25-35°C, and the casting speed is controlled at 2.0-2.4m / min, maintaining a constant speed to minimize liquid level fluctuations. The billets are cooled slowly in the insulation pit for more than 48 hours after leaving the production line.

[0049] 7. Heating: Use a walking beam heating furnace for heating, with the preheating section temperature at 880±20℃, the heating section temperature at 1100±20℃, the soaking section temperature at 1110±20℃, and the total heating time at 1.5 to 2.5 hours.

[0050] 8. Rolling, Shearing, and Cooling: The starting temperature for roughing is 980±20°C; the inlet temperature for finishing is 900±20°C; the temperature for the sizing and reducing mills is 880±20°C; the shearing temperature is 880±20°C; the air-cooling roller speed is 0.15-0.20 m / s for the head roller, with the roller speed increasing in increments of 2%-5%. The insulation covers are closed for the first half of the run and open for the second half (e.g., insulation covers 1#-20# are closed, and insulation covers 2#-22# are open). The fans are completely off; the opening of the Jialing device for the entire run (e.g., insulation covers 1#-25#) is 20-30%.

[0051] 9. Insulation channel slow cooling: Use insulation channel for slow cooling, and the insulation channel temperature is ≥60℃ to ensure the effective release of tissue stress and internal stress, thereby ensuring the performance requirements of the finished product and welding wire.

[0052] The finished wire rod has a ferrite + pearlite structure, with ferrite accounting for 85% to 90% by volume and pearlite accounting for 10% to 15%. The finished wire rod has a tensile strength of 530 to 560 MPa, an elongation of 28% to 33%, and a reduction in area of ​​74% to 81%. Figure 1 shown.

[0053] The following examples are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following examples.

[0054] Example:

[0055] This embodiment adopts the production method of the present invention to manufacture G4Si1 wire rod for low-aluminum and low-calcium gas shielded welding wire. The chemical composition of the steel in each embodiment is shown in Table 1, the converter smelting process, ladle alloying and static argon blowing parameters of each embodiment are shown in Table 2, the LF furnace refining and continuous casting process parameters of each embodiment are shown in Table 3, the rolling and cooling process parameters of each embodiment are shown in Table 4, the macroscopic defect inspection results of the ingots in each embodiment are shown in Table 5, the mechanical properties of the finished products in each embodiment are shown in Table 6, and the microstructure and non-metallic inclusion inspection results of the finished products in each embodiment are shown in Table 7.

[0056] Table 1 Chemical composition of steel (mass percentage, %)

[0057]

[0058] Table 2 Process parameters for converter smelting, ladle alloying and static argon blowing

[0059]

[0060] Table 3 LF furnace refining and continuous casting process parameters

[0061]

[0062] Table 4 Rolling and cooling process parameters

[0063]

[0064] Table 5 Results of macroscopic defects inspection of slab (grade)

[0065]

[0066] Table 6 Mechanical properties of finished products

[0067]

[0068] Table 7 Test results of finished product microstructure and non-metallic inclusions

[0069]

[0070] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire wire rod, characterized in that: The chemical composition of the wire rod is as follows by mass percentage: C: 0.080%~0.110%, Si: 0.80%~1.10%, Mn: 1.60%~1.80%, P≤0.020%, S: 0.006%~0.018%, Ca≤0.0010%, Al≤0.015%, Cr≤0.15%, Ni≤0.15%, Cu≤0.20%, and the rest are Fe and unavoidable impurities; the finished product structure of the wire rod is ferrite + pearlite structure, and by volume ratio, the ferrite accounts for 85%~90%, and the pearlite accounts for 10%~15%; the finished product performance of the wire rod is: tensile strength 530~560MPa, elongation after fracture 28%~33%, and cross-sectional shrinkage rate 74%~81%.

2. A method for producing a wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire as claimed in claim 1, characterized in that: The steps include: 1) KR hot metal pretreatment: spray desulfurizer into the hot metal ladle for desulfurization. After pretreatment, the sulfur content in the hot metal is ≤0.005%, and the slag is cleaned; 2) Converter smelting: Use top-bottom combined blowing converter for smelting, top blowing oxygen purity> 99.6%, oxygen pressure of 1.1-1.3MPa; combined blowing supplies argon, argon pressure of 1.1-1.3MPa; tapping temperature is 1595-1650℃, tapping end point C≤0.05% and P≤0.012% by mass percentage, slag is strictly prohibited, and spot blowing is avoided; 3) Ladle alloying: Alloying is carried out 2 minutes after steel tapping, with argon blowing time ≥ 5 minutes; active lime 27.02-27.76 kg / t steel, dolomite 10.2-10.8 kg / t steel; and silicon manganese alloy 24.5-25.5 kg / t steel. 4) Static argon blowing: argon blowing time ≥ 5min; the temperature of the molten steel after treatment is 1560℃~1570℃; 5) LF furnace refining: The furnace is maintained at a slightly positive pressure of 40-70 kPa, using submerged arc heating to prevent arc light leakage; 5.3-5.6 kg / t of active lime, 0.80-1.20 kg / t of fluorite, 0.45-0.50 kg / t of carbide slag, and 0.30-0.34 kg / t of ferrosilicon powder are added; reducing slag is produced with a basicity of R = CaO / SiO2 = 1.0-1.5; after deoxidation, silicon and manganese are fine-tuned by adding 4.65-5.35 kg / t of low-aluminum ferrosilicon, 2.5-3.5 kg / t of medium-carbon ferromanganese, and 0.2-0.3 kg / t of recarburizer; soft blowing time ≥ 15 min; LF furnace temperature at the exit is 1575°C-1590°C. 6) Continuous casting: adopt the whole process protection casting process, clean the tundish with argon before casting, and the purge time is ≥2min; the crystallizer electromagnetic stirring adopts continuous stirring mode, the electromagnetic stirring current is 230~270A, the frequency is 2~4Hz, and the end electromagnetic stirring adopts forward and reverse alternating stirring mode, the electromagnetic stirring current is 300~340A, and the frequency is 6~10Hz; low-carbon or carbon-free covering agent is used for the tundish, and calcium wire is prohibited; the crystallizer protection slag uses square billet low-carbon protection slag; the platform ladle temperature is 1573±5℃, the tundish temperature is 1530℃~1550℃, the superheat is maintained at 25℃~35℃, the pulling speed is 2.0~2.4m / min, and the pulling speed is constant; the billet is put into the holding pit for slow cooling for more than 48 hours after it comes off the line; 7) Heating: Use a walking beam heating furnace for heating, with the preheating section temperature at 880±20℃, the heating section temperature at 1100±20℃, the soaking section temperature at 1110±20℃, and the total heating time at 1.5 to 2.5 hours; 8) Rolling, spinning and cooling: Rough rolling temperature is 980±20℃; finishing rolling inlet temperature is 900±20℃; feed and sizing unit temperature is 880±20℃; spinning temperature is 880±20℃; air cooling roller speed: head roller speed is 0.15~0.20m / s, roller speed increase is set to increase by 2%~5%; insulation cover is closed in the first half and opened in the second half; fans are completely turned off; the opening of the Jialing device is 20%~30% throughout the process; 9) Slow cooling in the insulation channel: The rolled wire rod is slowly cooled in the insulation channel on the Stelmor slow cooling line, and the temperature of the insulation channel is ≥60℃.

3. The method for producing a wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire according to claim 2, characterized in that: In the step 1), during converter smelting, the molten iron accounts for 85% to 88% by weight, and the scrap steel accounts for 12% to 15% by weight.

4. The method for producing a wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire according to claim 2, characterized in that: In the step 3), low-aluminum ferrosilicon and low-carbon ferromanganese are used for alloying treatment.

5. The method for producing a wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire according to claim 2, characterized in that: In the step 4), when blowing argon, first blow vigorously for 2 to 3 minutes, then blow weakly; the flow rate of strong blowing argon is 780 to 820m 3 / h, weak blowing argon gas flow rate is 95~105m 3 / h.

6. The method for producing a wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire according to claim 2, characterized in that: In the step 5), the low-aluminum ferrosilicon added is FeSi75Al0.5-A, and in terms of mass percentage, the aluminum content in FeSi75Al0.5-A is less than 0.5%, and the calcium content is less than 1%.

7. The method for producing a wire rod for low-aluminum, low-calcium, sulfur-controlled gas shielded welding wire according to claim 2, characterized in that: The typical production process route is: blast furnace molten iron → KR desulfurization pretreatment → 100t converter smelting → LF furnace refining → 150mm×150mm eight-strand square billet continuous casting → heating in regenerative walking beam heating furnace → high-pressure water descaling → rough rolling → intermediate rolling → pre-finishing rolling → finishing rolling → sizing → wire laying → air cooling → coiling → slow cooling in Stelmor slow cooling line insulation channel.

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