A cost-effective low-alloy high-strength welding wire steel wire rod and its production method

Abstract

The invention provides a high-cost-performance low-alloy high-strength welding wire steel wire rod and a production method thereof. The chemical components are calculated by weight percentage as follows: C: 0.05-0.10%, Si: 0.50-0.90%, Mn: 1.40-1.80%, P≤0.015%, S≤0.015%, Cr: 0.30-0.60%, V: 0.03-0.08%, Cu≤0.15%, Ni≤0.10%, Ti: 0.08-0.15%, B: 0.002-0.006%, and the remainder is Fe and inevitable impurities. The invention uses a CrVB component system and adopts a low-temperature rolling and cooling process to make it have a structure F+B suitable for drawing, avoid the appearance of an abnormal martensitic structure, reduce the strength of the wire rod, and greatly improve the shrinkage and elongation. The method adopts a reasonable component system and process technology, improves the wire rod passability and structure uniformity, and realizes the user's annealing-free drawing processing requirements. The use of CrVB component system replaces Ni / Mo precious alloys to reduce costs. Compared with the same level GB / T 8110-2008 ER69-G, the cost is reduced by about RMB 2,200 / ton of steel, with obvious cost advantages.

Description

Technical Field

[0001] The invention belongs to the field of welding steel wire rods, and in particular relates to a high-cost-performance, low-alloy, high-strength welding steel wire rod and a production method thereof. Background Art

[0002] Welding wire steel is a slow-cooling steel. It is very easy to produce abnormal structures such as upper bainite or martensite during the production process of welding wire steel. The upper bainite has a feather-like shape and is a transformation product in the high temperature area of ​​bainite transformation. The formation temperature of upper bainite is relatively high. The ferrite bars and carbides in it are coarse, and its plastic deformation resistance is low. The cementite in the upper bainite is distributed in the form of discontinuous short rods between the ferrite bars. The distribution of ferrite and cementite has obvious directionality. At the same time, there are defects such as low carbon content, low supersaturation, and low dislocation density, which makes the ferrite bars have poor impact toughness and easily cause brittle fracture of welding wire steel during drawing. Martensite is a supersaturated solid solution of carbon dissolved in α-Fe. It is a metastable phase transformed from austenite through a diffusionless phase transformation. Its specific volume is greater than that of austenite, pearlite and other organizations. Although it has high strength and hardness, the brittleness of martensite is very high, which easily leads to brittle fracture of welding wire steel during drawing.

[0003] With the rapid development of high-end manufacturing, engineering machinery, coal mining machinery, bridges and other industries, the market demand for high-strength welding wire steel is also increasing year by year. 70kg grade high-strength welding wire steel is mainly used in Q690 steel solid welding wire for coal mining machinery. This series of steels improves the strength and toughness of weld deposited metal by adding different contents of alloy elements such as Ni, Mo, Cr, Ti, etc., but the content of precious alloys is high and the cost is high. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a cost-effective low-alloy high-strength welding wire steel wire rod and a production method thereof, adopting a CrVB component system, whose chemical composition by weight percentage is: C: 0.05-0.10%, Si: 0.50-0.90%, Mn: 1.40-1.80%, P≤0.015%, S≤0.015%, Cr: 0.30-0.60%, V: 0.03-0.08%, Cu≤0.15%, Ni≤0.10%, Ti: 0.08-0.15%, B: 0.002-0.006%, the rest are Fe and inevitable impurities. The present invention uses CrVB component system and adopts low-temperature rolling and cooling process. The steel wire rod produced has the F+B structure suitable for drawing. By reducing the appearance of abnormal martensitic structure, the strength of the wire rod is reduced, and the shrinkage and elongation are greatly improved. The method adopts a reasonable component system and process technology, and also improves the wire rod smoothness and structural uniformity, meeting the user's annealing-free drawing processing needs.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] A method for producing a cost-effective low-alloy high-strength welding wire steel wire rod comprises the following steps:

[0007] Step S1: steelmaking: converter smelting, deoxidation and alloying, steelmaking and tapping composition control requirements: C≤0.04%, P≤0.010%, tapping temperature≥1580℃; deoxidation and alloying are performed during tapping;

[0008] Step S2: Refining: After the LF refining furnace enters the station, slag-making materials are added, and low-carbon ferrochrome, electrolytic nickel, and ferrovanadium alloy are selected to adjust the composition after the white slag, and the weight percentages are Cr: 0.35-0.40%, Ni: 0.06-0.10%, and V: 0.030-0.060%; titanium iron wire is fed once before soft argon blowing; the weight percentage of Ti is adjusted to 0.08-0.10%, and then the boron iron wire is fed to adjust the weight percentage of boron B to: 0.0028-0.0032%. After the LF exits the station, the molten steel is soft-blown with argon;

[0009] Step S3: Billet casting: The molten steel is poured on a continuous casting machine, the target superheat is 20-30°C, the casting speed is controlled at 2.2-2.4 m / min, the water flow rate of the crystallizer is 1850 L / min, the electromagnetic stirring parameters of the crystallizer are current intensity 300-400 A, frequency 3-4 Hz, the terminal electromagnetic stirring parameters are current intensity 250-300 A, frequency 8-10 Hz, the secondary cooling water flow rate is 0.8-1.0 L / kg, and the superheat of the casting is protected at 20-30°C throughout the casting process;

[0010] Step S4: controlled rolling, controlled cooling and wire rolling: the temperature range of the soaking section of the heating furnace is 1030-1160°C, the rolling start temperature is 960-1000°C, the final rolling temperature is 850-870°C, the wire laying temperature is 820-850°C, the temperature out of the insulation cover is 460-570°C, the coiling temperature is 320-400°C, and the electromagnetic stirring parameters at the end of the billet casting are: current intensity 250-300A, frequency 8-10Hz, to obtain the wire rod;

[0011] Step S5: inspecting, packaging and storing the wire rods.

[0012] In the above scheme, the steelmaking and tapping composition control requirements in step S1 are: C: 0.024%, P: 0.012%, and tapping temperature: 1582°C; deoxidation and alloying are performed during tapping, and the order and weight of adding alloys are: after 1 / 4 of the steel is tapped, 21kg / t of high-silicon silicon manganese and 1.2kg / t of ferrosilicon are added for alloying; after adding the alloy, 8.0kg / t of lime and 1.8kg / t of fluorite slag-making materials are added in sequence to form refined primary slag.

[0013] In the above scheme, in step S2, slag-making material is added after the LF refining furnace enters the station. The components of the slag-making material are 1kg / t of lime and 0kg / t of fluorite, so that the slag basicity R is 2.5; the refining process uses calcium carbide and ferrosilicon powder in a weight percentage of 1:4 for diffusion deoxidation, which is added to the slag surface in small amounts and multiple times, with a total addition amount of 2.1kg / t; small amounts and multiple batches, and the white slag time is 17min.

[0014] In the above scheme, the weight percentage of the components in step S2 is controlled to be 0.35% for Cr, 0.07% for Ni and 0.038% for V; the titanium iron wire is fed once before soft argon blowing; the weight percentage of Ti is adjusted to 0.09%, and then the boron iron wire is fed, and the weight percentage of B is adjusted to 0.0031%, and calcium treatment is not allowed.

[0015] In the above scheme, in the step S2 refining, after LF leaves the station, the molten steel is soft-blown with argon, the argon flow rate is 20NL / min, and the soft-blowing time is 15 minutes.

[0016] In the above scheme, the specific steps of pouring the small square billet in step S3 include: pouring molten steel on a continuous casting machine, purging the impact zone of the tundish and each flow interval with argon before pouring, and then starting the ladle slide to start pouring, with a target superheat of 25°C, a pulling speed controlled at 2.2m / min, a crystallizer water flow rate of 1850L / min, crystallizer electromagnetic stirring parameters of 300A current and 4Hz frequency, terminal electromagnetic stirring parameters of 250A current and 10Hz frequency, and a secondary cooling water flow rate of 0.8L / kg.

[0017] In the above scheme, the specific operations of controlled rolling and controlled cooling and wire rolling in step S4 include: the temperature range of the soaking section of the heating furnace is 1060°C, the rolling start temperature is 980°C, the final rolling temperature is 860°C, the wire laying temperature is 820°C, the insulation cover temperature is 500°C, and the coiling temperature is 380°C.

[0018] A cost-effective low-alloy high-strength welding wire steel wire rod is produced using the cost-effective low-alloy high-strength welding wire steel wire rod production method, and its chemical composition is calculated by weight percentage: C: 0.05-0.10%, Si: 0.50-0.90%, Mn: 1.40-1.80%, P≤0.015%, S≤0.015%, Cr: 0.30-0.60%, V: 0.03-0.08%, Cu≤0.15%, Ni≤0.10%, Ti: 0.08-0.15%, B: 0.002-0.006%, and the rest is Fe and unavoidable impurities.

[0019] In the above scheme, the chemical composition is calculated by weight percentage as follows: C: 0.05%, Si: 0.67%, Mn: 1.48%, P: 0.015%, S: 0.008%, Cr: 0.34%, V: 0.038%, Cu: 0.02%, Ni: 0.07%, Ti: 0.08%, B: 0.0030%, and the rest is Fe and unavoidable impurities.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The chemical composition of the cost-effective low-alloy high-strength welding wire steel wire rod of the present invention is calculated as follows by weight percentage: C: 0.05-0.10%, Si: 0.50-0.90%, Mn: 1.40-1.80%, P≤0.015%, S≤0.015%, Cr: 0.30-0.60%, V: 0.03-0.08%, Cu≤0.15%, Ni≤0.10%, Ti: 0.08-0.15%, B: 0.002-0.006%, and the rest is Fe and inevitable impurities. The central segregation of the steel wire rod billet is ≤1.5 level, and the shrinkage cavity is ≤1.0 level. The CrVB component system is used, and low-temperature rolling and cooling processes are adopted, so that the steel wire rod has a structure F+B suitable for drawing. By avoiding the appearance of abnormal martensitic structure, the strength of the wire rod is reduced, the surface shrinkage and elongation are greatly improved, the wire rod smoothness and structural uniformity are also improved, and the user's annealing-free drawing processing needs are met. The present invention uses a CrVB component system to replace the Ni / Mo precious alloy, and significantly reduces the cost compared with the same level GB / T 8110-2008 ER69-G. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the test results of the mechanical properties of the wire rod according to Example 1 of the present invention.

[0023] Figure 2 It is a schematic diagram of the metallographic structure of Example 1 of the present invention.

[0024] Figure 3 It is a schematic diagram of a ratio of metallographic structures of the present invention. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail below, which are intended to explain the present invention but should not be construed as limiting the present invention.

[0026] A method for producing a cost-effective low-alloy high-strength welding wire steel wire rod comprises the following steps:

[0027] Step S1: steelmaking; specifically:

[0028] Deoxidation and alloying in converter smelting: requirements for tapping composition control: C≤0.04%, P≤0.010%, tapping temperature≥1580℃; deoxidation and alloying are carried out during tapping, and the order and weight of adding alloys are as follows: after 1 / 4 of the steel is tapped, 21-23kg / t of high silicon silicon manganese and 1.0-1.5kg / t of ferrosilicon are added for alloying; after adding the alloy, 8.0-9.0kg / t of lime and 1.8-2.2kg / t of fluorite slag-making materials are added in sequence to form refined primary slag;

[0029] Step S2: Refining; specifically:

[0030] 1) After the LF refining furnace enters the station, slag-making materials are added. The components of the slag-making materials are 0-4kg / t lime and 0-2kg / t fluorite, so that the slag has good fluidity and a basicity R of 1.8-3.0; the refining process uses calcium carbide and ferrosilicon powder by weight percentage.

[0031] The ratio is 1:4 for diffusion deoxidation, and it is added to the slag surface in small amounts and multiple times, with a total addition amount of 1.9-2.3kg / t; small amounts and multiple batches, and the white slag time is ≥15min;

[0032] 2) Composition control: After white slag, according to the composition of molten steel process samples, low-carbon ferrochrome, electrolytic nickel, and ferrovanadium alloys are selected to adjust the composition weight percentages Cr: 0.35-0.40%, Ni: 0.06-0.10%, and V: 0.030-0.060%; before soft argon blowing, titanium iron wire is fed once to adjust the Ti weight percentage to: 0.08-0.10%, and then boron iron wire is fed to adjust the B weight percentage to: 0.0028-0.0032%, and calcium treatment is not allowed. V, B, and Ti are used for microalloying and grain refinement, so that the weld metal obtains a uniform and fine acicular ferrite structure, thereby achieving the strengthening and toughening of the weld metal;

[0033] 3) After LF leaves the station, the molten steel is soft-blown with argon gas, with an argon gas flow rate of 10-40NL / min and a soft-blowing time of ≥10 minutes;

[0034] Step S3: billet casting; specifically:

[0035] The molten steel is poured on the continuous casting machine. Before pouring, the impact zone of the tundish and each flow interval are purged with argon gas, and then the ladle slide is started to start pouring. The target superheat is 20-30°C, the pulling speed is controlled at 2.2-2.4m / min, the water flow rate of the crystallizer is 1850L / min, the electromagnetic stirring parameters of the crystallizer are current intensity 300-400A, frequency 3-4Hz, the terminal electromagnetic stirring parameters are current intensity 250-300A, frequency 8-10Hz, the secondary cooling water flow rate is 0.8-1.0L / kg, and the pouring process is protected throughout the pouring process. The above steps can effectively improve the internal quality of the ingot and reduce the degree of inclusions and segregation.

[0036] Step S4: controlled rolling, controlled cooling and wire rolling to obtain wire rod;

[0037] Specifically, the temperature range of the heating furnace soaking section is 1030~1160℃, the rolling start temperature is 960~1000℃, the final rolling temperature is 850~870℃, the wire laying temperature is 820~850℃, the temperature out of the insulation cover is 460~570℃, and the coiling temperature is 320~400℃. During the rolling process, the wire laying temperature, roller speed and insulation cover opening are reduced to adjust the rolling cooling speed, so that the structure can undergo sufficient phase change in the insulation cover, solving the problem of high strength and abnormal structure of high-strength welding wire steel;

[0038] Step S5: inspecting, packaging and storing the wire rods.

[0039] Example 1

[0040] A cost-effective low-alloy high-strength welding wire steel wire rod, whose chemical composition is calculated by weight percentage: C: 0.05%, Si: 0.67%, Mn: 1.48%, P: 0.015%, S: 0.008%, Cr: 0.34%, V: 0.038%, Cu: 0.02%, Ni: 0.07%, Ti: 0.08%, B: 0.0030%, and the rest is Fe and unavoidable impurities.

[0041] A method for producing a cost-effective low-alloy high-strength welding wire steel wire rod comprises the following steps:

[0042] Step S1: steelmaking; according to this embodiment, preferably, converter smelting deoxidation alloying: tapping composition control requirements: C: 0.024%, P: 0.012%, tapping temperature: 1582°C; deoxidation alloying is performed during tapping, and the order and weight of adding alloys are: after 1 / 4 of the steel is tapped, 21kg / t of high silicon silicon manganese and 1.2kg / t of ferrosilicon are added for alloying; after adding the alloy, 8.0kg / t of lime and 1.8kg / t of fluorite slag-making materials are added in sequence to form refined primary slag;

[0043] Step S2: Refining; According to this embodiment, preferably:

[0044] 1) After the LF refining furnace enters the station, slag-making materials are added. The components of the slag-making materials are 1kg / t lime and 0kg / t fluorite, so that the slag has good fluidity and a basicity R of 2.5; the refining process uses calcium carbide and ferrosilicon powder in a weight percentage of 1:4 for diffusion deoxidation, and adds it to the slag surface in small amounts and multiple times, with a total addition amount of 2.1kg / t; small amounts and multiple batches, white slag time: 17min;

[0045] 2) Composition control: After white slag, according to the composition of molten steel process sample, low carbon ferrochrome, electrolytic nickel, and ferrovanadium alloy are selected to adjust the composition weight percentage to Cr: 0.35%, Ni: 0.07%, and V: 0.038%; before soft argon blowing, titanium iron wire is fed once to adjust the Ti weight percentage to: 0.09%, and then the boron iron wire is fed to adjust the B weight percentage to: 0.0031%, and calcium treatment is not allowed;

[0046] 3) After LF leaves the station, the molten steel is soft-blown with argon gas, with an argon gas flow rate of 20NL / min and a soft-blowing time of 15 minutes;

[0047] Step S3: pouring of small square billets; according to this embodiment, preferably, the molten steel is poured on a continuous casting machine, and the impact zone of the tundish and each flow interval are purged with argon before pouring, and then the ladle slide is started to pour, the target superheat is 25°C, the pulling speed is controlled at 2.2m / min, the water flow rate of the crystallizer is 1850L / min, the electromagnetic stirring parameters of the crystallizer are 300A current intensity and 4Hz frequency, the terminal electromagnetic stirring parameters are 250A current intensity and 10Hz frequency, the secondary cooling water flow rate is 0.8L / kg, and the pouring process is protected throughout the pouring process. The above parameters can effectively improve the internal quality of the ingot and reduce the degree of inclusions and segregation;

[0048] Step S4: controlled rolling, controlled cooling and wire rolling to obtain wire rod; according to this embodiment, preferably, the temperature range of the soaking section during the rolling process is 1060°C, the rolling start temperature is 980°C, the final rolling temperature is 860°C, the wire laying temperature is 820°C, the temperature out of the insulation cover is 500°C, and the coiling temperature is 380°C. During the rolling process, the wire laying temperature, the roller speed and the insulation cover are reduced to adjust the rolling cooling speed, so that the structure undergoes sufficient phase change in the insulation cover, thereby solving the problem of high strength and abnormal structure of high-strength welding wire steel;

[0049] Step S5: inspecting, packaging and storing the wire rods.

[0050] Comparative Example

[0051] The difference between the comparative example and Example 1 is that the alloy system is different. The comparative example adopts a NiMo alloy system, wherein Mo: 0.35%, the amount of ferromolybdenum added is 5.9 kg / t; Ni: 0.60%, the amount of electrolytic nickel added is 6.4 kg / t.

[0052] like Figure 1As shown, the cost-effective low-alloy high-strength welding wire steel wire rod produced by the above method has stable mechanical properties. 8 samples were cut from the head and tail of a wire rod in Example 1 and the comparative example respectively, and a total of 16 samples were tested. Combined with what is shown in Table 1, the tensile strength of Example 1 of the present application is 519-597Mpa, the extreme difference in tensile strength is 78Mpa, the elongation after fracture is 28-30%, and the cross-sectional reduction rate is 78-82%. It can be seen that the tensile strength of Example 1 of the present application is ≤650Mpa, the extreme difference in tensile strength is ≤80Mpa, the elongation after fracture is ≥28%, and the cross-sectional reduction rate is ≥78%, which can realize the user's wire rod annealing-free drawing to φ1.2mm gas-shielded solid welding wire, and the process is smooth and there is no wire breakage. In the comparative example, the tensile strength is 685-779Mpa, the extreme difference of tensile strength is 94Mpa, the elongation after fracture is 21-24%, and the cross-sectional shrinkage is 59-68%. It can be seen that the tensile strength of the comparative example is greater than 650Mpa, the extreme difference of tensile strength is greater than 80Mpa, the elongation after fracture is less than 28%, and the cross-sectional shrinkage is less than 78%. By comparison, it can be seen that the performance of the comparative wire rod fluctuates greatly, the strength is higher, and the elongation and elongation after fracture are low, which is not conducive to user drawing processing.

[0053] Table 1 Comparison of mechanical properties between Example 1 and Comparative Example

[0054] project Tensile strength / Mpa Poor tensile strength / Mpa Elongation after break / % Sectional shrinkage / % Example 1 519-597 78 28-30 78-82 Comparative Example 685-779 94 21-24 59-68

[0055] like Figure 2 and Figure 3 As shown in the figure, under the condition of 500 times magnification, the high-cost-effective low-alloy high-strength welding wire steel wire rod produced by the above method has the structure of F+a small amount of B, good overall uniformity of the structure, and no obvious difference between the core and edge grains. The structure of the comparative wire rod is F+B+a small amount of M, the overall uniformity of the structure is poor, and the core grains are obviously coarser than the edge.

[0056] In summary, the present invention provides a method for producing a cost-effective low-alloy high-strength welding wire steel wire rod, using a CrVB component system, and adopting a low-temperature rolling and cooling process, so that it has a structure F+B suitable for drawing, avoiding the appearance of abnormal martensite structure, reducing the strength of the wire rod, and greatly improving the shrinkage and elongation. The method adopts a reasonable component system and process technology to improve the wire rod passability and structural uniformity, and meet the user's annealing-free drawing processing requirements. The present invention also uses a CrVB component system to replace Ni / Mo precious alloys. Compared with the same level GB / T 8110-2008 ER69-G, the cost is reduced by about 2,200 yuan / ton of steel, with obvious cost advantages, which greatly reduces the cost.

[0057] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0058] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing a cost-effective low-alloy high-strength welding wire steel wire rod, characterized in that: The following steps are involved: Step S1: steelmaking: converter smelting, deoxidation and alloying, steelmaking and tapping composition control requirements: C≤0.04%, P≤0.010%, tapping temperature≥1580℃; deoxidation and alloying are performed during tapping; Step S2: Refining: After the LF refining furnace enters the station, slag-making materials are added, and low-carbon ferrochrome, electrolytic nickel, and ferrovanadium alloy are selected to adjust the composition after the white slag, and the weight percentages are Cr: 0.35%, Ni: 0.07%, and V: 0.038%; titanium iron wire is fed once before soft argon blowing; the weight percentage of Ti is adjusted to 0.09%, and then the boron iron wire is fed to adjust the weight percentage of boron B to 0.0031%. After the LF exits the station, the molten steel is soft-blown with argon; Step S3: Billet casting: The molten steel is poured on a continuous casting machine, the target superheat is 20-30°C, the casting speed is controlled at 2.2-2.4 m / min, the water flow rate of the crystallizer is 1850 L / min, the electromagnetic stirring parameters of the crystallizer are current intensity 300-400 A, frequency 3-4 Hz, the terminal electromagnetic stirring parameters are current intensity 250-300 A, frequency 8-10 Hz, the secondary cooling water flow rate is 0.8-1.0 L / kg, and the superheat of the casting is protected at 20-30°C throughout the casting process; Step S4: controlled rolling, controlled cooling and wire rolling: the temperature range of the soaking section of the heating furnace is 1030-1160°C, the rolling start temperature is 960-1000°C, the final rolling temperature is 850-870°C, the wire laying temperature is 820-850°C, the temperature out of the insulation cover is 460-570°C, the coiling temperature is 320-400°C, and the electromagnetic stirring parameters at the end of the billet casting are: current intensity 250-300A, frequency 8-10Hz, to obtain the wire rod; Step S5: inspecting, packaging and storing the wire rods.

2. The method for producing a cost-effective low-alloy high-strength welding wire steel wire rod according to claim 1, characterized in that: The steelmaking and tapping composition control requirements in step S1 are as follows: C: 0.024%, P: 0.012%, and tapping temperature: 1582° C. Deoxidation and alloying are performed during tapping, and the order and weight of adding alloys are as follows: after 1 / 4 of the steel is tapped, 21 kg / t of high silicon silicon manganese and 1.2 kg / t of ferrosilicon are added for alloying; after adding the alloy, 8.0 kg / t of lime and 1.8 kg / t of fluorite slag-making materials are added in sequence to form refined primary slag.

3. The method for producing a cost-effective low-alloy high-strength welding wire steel wire rod according to claim 1, characterized in that: In the step S2, slag-making material is added after the LF refining furnace enters the station. The components of the slag-making material are 1kg / t lime and 0kg / t fluorite, so that the slag basicity R is 2.5; the refining process uses calcium carbide and ferrosilicon powder in a weight percentage of 1:4 for diffusion deoxidation, which is added to the slag surface in small amounts and multiple times, with a total addition amount of 2.1kg / t; small amounts and multiple batches, and the white slag time is 17min.

4. The method for producing a cost-effective low-alloy high-strength welding steel wire rod according to claim 1, characterized in that: In the step S2 refining, after LF leaves the station, the molten steel is soft-blown with argon, with an argon flow rate of 20 NL / min and a soft-blowing time of 15 minutes.

5. The method for producing a cost-effective low-alloy high-strength welding wire steel wire rod according to claim 1, characterized in that: The specific steps of pouring the small square billet in step S3 include: pouring molten steel on a continuous casting machine, purging the impact zone of the tundish and each flow interval with argon before pouring, and then starting the ladle slide to start pouring, with a target superheat of 25°C, a pulling speed controlled at 2.2m / min, a crystallizer water flow rate of 1850L / min, crystallizer electromagnetic stirring parameters of 300A current and 4Hz frequency, terminal electromagnetic stirring parameters of 250A current and 10Hz frequency, and a secondary cooling water flow rate of 0.8L / kg.

6. The method for producing a cost-effective low-alloy high-strength welding steel wire rod according to claim 1, characterized in that: The specific operations of controlled rolling and controlled cooling and wire rolling in step S4 include: the temperature range of the soaking section of the heating furnace is 1060°C, the rolling start temperature is 980°C, the final rolling temperature is 860°C, the wire laying temperature is 820°C, the temperature out of the insulation cover is 500°C, and the coiling temperature is 380°C.

7. A cost-effective low-alloy high-strength welding wire steel wire rod, characterized in that: The low alloy high strength welding wire steel wire rod is produced by the production method of any one of claims 1 to 6, and its chemical composition is calculated by weight percentage: C: 0.05-0.10%, Si: 0.50-0.90%, Mn: 1.40-1.80%, P≤0.015%, S≤0.015%, Cr: 0.30-0.60%, V: 0.03-0.08%, Cu≤0.15%, Ni≤0.10%, Ti: 0.08-0.15%, B: 0.002-0.006%, and the rest are Fe and unavoidable impurities.

8. The cost-effective low-alloy high-strength welding steel wire rod according to claim 7, characterized in that: Its chemical composition by weight percentage is: C: 0.05%, Si: 0.67%, Mn: 1.48%, P: 0.015%, S: 0.008%, Cr: 0.34%, V: 0.038%, Cu: 0.02%, Ni: 0.07%, Ti: 0.08%, B: 0.0030%, and the rest is Fe and unavoidable impurities.

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