A method for producing H08Mn welding rod steel based on converter direct ascent and pre-slag washing

Abstract

The invention provides a production method of H08Mn welding rod steel based on converter direct ascending and pre-melted slag washing, comprising: injecting blast furnace molten iron into a converter to smelt to form molten steel, when reaching the end point of smelting, injecting the molten steel into a ladle to block slag for tapping, adding pre-melted refined slag into the ladle at the beginning of tapping to slag wash the molten steel, and adding lime powder and aluminum particles into the ladle after tapping is completed; blowing argon into the molten steel from the bottom of the ladle, determining oxygen and measuring temperature of the molten steel, and feeding aluminum wire into the molten steel; blowing argon into the molten steel from the bottom of the ladle, feeding calcium iron cored wire into the molten steel, and blowing argon into the molten steel from the bottom of the ladle; pouring the molten steel into a tundish, flowing into a water-cooled crystallizer through the tundish, and after the molten steel solidifies into a hard shell, continuously pulling it out from the bottom outlet of the water-cooled crystallizer and spraying water for cooling, and cutting it into billets after it is completely solidified to obtain H08Mn welding rod steel. The present invention adopts a converter direct-up process route combined with pre-melting refined slag and slag washing to achieve precise endpoint control and tapping slag modification.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and relates to a production method of H08Mn welding rod steel based on converter direct ascending and pre-melted slag washing. Background Art

[0002] H08Mn welding rod steel is an important raw material for welding rod production. It is a steel with low carbon, low silicon, low aluminum and a certain manganese content. Its composition requirements are C 0.05%-0.09%, Si≤0.06%, Mn 0.85%-1.05%, P≤0.025%, S≤0.025%. At present, the domestic industry produces H08Mn welding rod steel, basically adopting the process route of "blast furnace molten iron → converter → LF furnace → continuous casting → rolling".

[0003] Aluminum-containing deoxidizers are added during converter smelting for deoxidation. During the refining process, the molten steel absorbs oxygen and nitrogen severely, and aluminum-containing deoxidizers need to be added for continuous deoxidation. The addition of aluminum-containing deoxidizers will form a large amount of high-melting-point alumina inclusions, which are easy to accumulate in the water mouth of the ladle and affect the castability of the molten steel. However, if the deoxidation depth is insufficient, bubble defects are prone to occur in the ingot. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for producing H08Mn welding rod steel based on direct converter and pre-melted slag washing. The present invention adopts a direct converter process route combined with pre-melted refined slag washing, which can achieve precise endpoint control and steel-making slag modification, and the production cost can be significantly reduced. The production cost can be reduced by 25-40 yuan / ton.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for producing H08Mn welding rod steel based on converter direct loading and pre-slag washing, the method comprising the following steps:

[0007] (I) Converter smelting: molten iron from a blast furnace is poured into a converter for smelting to form molten steel. When the carbon content, phosphorus content and sulfur content in the molten steel reach the target values, the smelting end point is reached. The molten steel in the converter is poured into a ladle for slag blocking and tapping. At the beginning of tapping, pre-melted refined slag is added to the ladle to wash the molten steel. After tapping, lime powder and aluminum particles are added to the ladle.

[0008] (II) Slag washing and refining: argon gas is continuously blown into the molten steel from the bottom of the ladle for a first argon blow. After blowing argon for a period of time, the molten steel is oxygenated and the temperature is measured. According to the oxygen determination result, aluminum wire is fed into the molten steel to adjust the oxygen content in the molten steel to the target value; then, argon gas is blown into the molten steel from the bottom of the ladle again for a second argon blow. After blowing argon for a period of time, calcium iron cored wire is fed into the molten steel for calcium treatment. After all the calcium wires are fed, argon gas is continuously blown into the molten steel from the bottom of the ladle again for a third argon blow;

[0009] (III) Continuous casting: Pour molten steel into a tundish, and flow into a water-cooled crystallizer through the tundish. After the molten steel solidifies into a hard shell, it is continuously pulled out from the bottom outlet of the water-cooled crystallizer and sprayed with water for cooling. After it is completely solidified, it is cut into billets to obtain the H08Mn welding rod steel.

[0010] The present invention adopts a converter direct-to-steam process route combined with pre-melted refined slag washing, and uses pre-melted refined slag to modify the molten steel during the slag blocking and steel-making process, which can ensure that the steel slag is quickly slag-formed; then, through argon station calcium treatment and argon soft blowing and other processes, it is ensured that the molten steel meets the conditions for casting on the stage, and the stable casting of continuous casting molten steel is achieved, so as to achieve the purpose of stabilizing the quality of the molten steel. Compared with the LF refining process, the slag washing and refining process adopted in the present invention can avoid the secondary oxygen and nitrogen absorption of the molten steel during the refining process, and improve the castability of the molten steel. The advantage of the production process provided by the present invention is that it can achieve precise endpoint control and steel-making slag modification, and the production cost can be significantly reduced, and the production cost can be reduced by 25-40 yuan / ton.

[0011] As a preferred technical solution of the present invention, in step (I), the sulfur content of the molten iron in the blast furnace before entering the furnace is ≤0.035wt%, for example, it can be 0.02wt%, 0.021wt%, 0.022wt%, 0.023wt%, 0.024wt%, 0.025wt%, 0.026wt%, 0.027wt%, 0.028wt%, 0.029wt%, 0.03wt%, 0.031wt%, 0.032wt%, 0.03 3wt%, 0.034wt% or 0.035wt%; phosphorus content ≤0.150wt%, for example, it can be 0.13wt%, 0.132wt%, 0.134wt%, 0.136wt%, 0.138wt%, 0.140wt%, 0.142wt%, 0.144wt%, 0.146wt%, 0.148wt% or 0.150wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0012] When the smelting end point is reached, the carbon content in the molten steel is 0.04-0.07wt%, for example, it can be 0.04wt%, 0.042wt%, 0.044wt%, 0.046wt%, 0.048wt%, 0.05wt%, 0.052wt%, 0.054wt%, 0.056wt%, 0.058wt%, 0.06wt%, 0.062wt%, 0.064wt%, 0.066wt%, 0.068wt% or 0.07wt%; the phosphorus content is ≤0.022wt%, for example, it can be 0.01wt%, 0.011wt%, 0.012wt%, 0.013wt%, 0.014wt%, 0.0 % , 0.014wt%, 0.015wt%, 0.016wt%, 0.017wt%, 0.018wt%, 0.019wt%, 0.02wt%, 0.021wt% or 0.022wt%; sulfur content ≤ 0.023wt%, for example, it can be 0.01wt%, 0.011wt%, 0.012wt%, 0.013wt%, 0.014wt%, 0.015wt%, 0.016wt%, 0.017wt%, 0.018wt%, 0.019wt%, 0.02wt%, 0.021wt%, 0.022wt% or 0.023wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] As a preferred technical solution of the present invention, in step (I), the pre-melted refined slag is calcium-aluminum pre-melted refined slag.

[0014] The alumina inclusions produced by aluminum granule deoxidation have a high melting point and are solid at the continuous casting temperature. They are easily accumulated at the water inlet of the tundish, causing water inlet blockage. Moreover, the alumina inclusions remaining in the steel are hard and brittle compared to the steel matrix. They are easily broken during the rolling process and are continuously distributed along the rolling direction, causing serious defects. The density of alumina inclusions is lower than that of molten steel. If the form of aluminum deoxidation products can be controlled to make them liquid at the steelmaking continuous casting temperature, such deoxidation products can be floated from the molten steel and removed before entering the tundish. This can not only reduce the blockage problem of the water inlet of the tundish and ensure the smooth continuous casting, but also increase the cleanliness of the steel and improve the inclusion compliance rate of the steel. Therefore, the present invention adds calcium-aluminum pre-melted refined slag to the molten steel during the slag blocking and steelmaking process, which can effectively reduce the contents of oxygen, sulfur and non-metallic inclusions in the molten steel, and can reduce the oxygen content to below 0.002wt%, and the sulfur content to below 0.05wt%; at the same time, the calcium-aluminum pre-melted refined slag continuously collides, merges, grows and floats while flowing and stirring with the molten steel, so as to achieve the adsorption of alumina inclusions, thereby achieving the purpose of sufficient deoxidation, desulfurization and impurity removal, and then further completes the floating removal of inclusions through slag washing and refining.

[0015] The addition ratio of the pre-melted refined slag is: 2-8 kg of pre-melted refined slag per ton of molten steel, for example, it can be 2.0 kg, 2.5 kg, 3.0 kg, 3.5 kg, 4.0 kg, 4.5 kg, 5.0 kg, 5.5 kg, 6.0 kg, 6.5 kg, 7.0 kg, 7.5 kg or 8.0 kg, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] The control of silicon element is quite critical in the smelting of H08Mn steel. In the present invention, the main source of silicon is calcium-aluminum pre-melted refined slag. In order to meet the requirements of qualified drawing and welding properties of the product in the subsequent process and reduce the probability of bubble generation in the continuous casting billet, the present invention specifically limits the addition ratio of pre-melted refined slag to: 2-8kg pre-melted refined slag per ton of molten steel.

[0017] As a preferred technical solution of the present invention, in step (Ⅰ), the temperature of the molten steel during slag blocking and steel tapping is 1620-1680°C, for example, it can be 1620°C, 1625°C, 1630°C, 1635°C, 1640°C, 1645°C, 1650°C, 1655°C, 1660°C, 1665°C, 1670°C, 1675°C or 1680°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0018] The proportion of lime powder added is: 2-3kg of lime powder per ton of molten steel, for example, it can be 2.0kg, 2.1kg, 2.2kg, 2.3kg, 2.4kg, 2.5kg, 2.6kg, 2.7kg, 2.8kg, 2.9kg or 3.0kg, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] The addition ratio of the aluminum particles is: 0.1-1 kg of aluminum particles per ton of molten steel, for example, it can be 0.1 kg, 0.2 kg, 0.3 kg, 0.4 kg, 0.5 kg, 0.6 kg, 0.7 kg, 0.8 kg, 0.9 kg or 1.0 kg, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] When the slag blocking and steel tapping is completed to 1 / 3, medium carbon ferromanganese alloy or low carbon ferromanganese alloy is added to the molten steel.

[0021] The addition ratio of the medium carbon ferromanganese alloy or the low carbon ferromanganese alloy is: 12-14kg of medium carbon ferromanganese alloy or low carbon ferromanganese alloy per ton of molten steel, for example, it can be 12kg, 12.2kg, 12.4kg, 12.6kg, 12.8kg, 13kg, 13.2kg, 13.4kg, 13.6kg, 13.8kg or 14kg, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] After adding aluminum particles, once the aluminum particles are excessive, the castability of the molten steel becomes poor, affecting the billet forming rate of the casting billet, and in severe cases, the casting stops due to flocculent flow. Therefore, the present invention particularly optimizes the appropriate amount of aluminum particles, lime powder and medium carbon ferromanganese alloy addition, so as to ensure that the continuous casting billet does not have subcutaneous bubble defects and the molten steel has good castability.

[0023] When aluminum particles (Al), lime powder (Ca) and medium (low) carbon ferromanganese alloy (Mn) are jointly deoxidized, a manganese-rich zone is formed around the aluminum particles, thereby improving the solubility of the aluminum particles, which is beneficial to enhancing the deoxidation ability of the lime powder and the aluminum particles. The present invention mainly uses calcium and manganese deoxidation and aluminum deoxidation as a supplement, optimizes the addition amount of aluminum blocks, lime powder and silicon-manganese alloy, ensures that the aluminum content in the molten steel during the entire smelting process reaches a lower control level under the premise of ensuring good deoxidation, so as to prevent the large-scale generation of aluminum oxide inclusions and facilitate the improvement of the purity of the molten steel.

[0024] The present invention reduces the amount of aluminum added by compounding a plurality of deoxidizers, and can control the aluminum content in molten steel to be less than or equal to 0.01wt% during the smelting and refining process. All the aluminum is added after the converter furnace, and the primary deoxidation product is in the shape of corals. During the slag washing and refining process, the corals can be easily collided, combined, grown, and floated by argon blowing and stirring, and thus adsorbed and dissolved by the slag.

[0025] H08Mn welding rod steel has strict requirements on composition, including the control of harmful elements and inclusions such as C, Si, Mn, P, S, etc., especially the reasonable control of C and Mn. Although Mn element is a good deoxidizer and desulfurizer, it can eliminate and weaken the hot brittleness caused by sulfur element and improve the hot working performance of steel, but too high Mn content can easily cause central segregation of ingot and increase the tendency of bainite to form in the center of wire rod. Therefore, the present invention specifically limits the addition ratio of medium (low) carbon ferromanganese alloy to 12-14kg of medium (low) carbon ferromanganese alloy per ton of molten steel.

[0026] As a preferred technical solution of the present invention, in step (II), the diameter of the aluminum wire is 8-13 mm, for example, it can be 8 mm, 9 mm, 10 mm, 11 mm, 12 mm or 13 mm, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] The feeding ratio of the aluminum wire is: 0.20-1 kg of aluminum wire per ton of molten steel, for example, it can be 0.2 kg, 0.3 kg, 0.4 kg, 0.5 kg, 0.6 kg, 0.7 kg, 0.8 kg, 0.9 kg or 1 kg, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] The wire feeding speed of the aluminum wire is 100-150 m / min, for example, it can be 100 m / min, 105 m / min, 110 m / min, 115 m / min, 120 m / min, 125 m / min, 130 m / min, 135 m / min, 140 m / min, 145 m / min or 150 m / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] When feeding aluminum wire, severe thermite reaction will occur. Thermite reaction is an exothermic reaction with aluminum and iron oxide as main reactants. When the temperature exceeds 1250°C, aluminum will oxidize and burn violently, releasing a large amount of heat energy. The temperature of this exothermic reaction can reach above 3000°C, which has a certain impact on molten steel. Therefore, it is necessary to strictly control the feeding ratio of aluminum wire. The present invention specifically limits the feeding of 0.20-1kg aluminum wire per ton of molten steel. When the feeding amount of aluminum wire exceeds the numerical range defined in the present invention, the temperature of the molten steel will increase by 5-10°C in a short time due to the violent thermite reaction, so that the deoxidation products will affect the quality of the molten steel.

[0030] The target value of oxygen content in the molten steel is 10-80ppm, for example, it can be 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm or 80ppm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] After the steel is tapped, part of the molten steel will still remain in the converter when the slag-blocking slide plate is closed, which is a disadvantageous factor in terms of both production cost and slag splashing and furnace protection. In actual production, this part of the remaining molten steel still needs to be poured into the ladle, but the remaining part of the molten steel contains slag, and pouring it and the remaining molten steel into the ladle is not conducive to the quality control of the molten steel. Therefore, the present invention feeds aluminum wire at the initial stage of argon blowing to control the Al s content (Al dissolved in the molten steel) in the molten steel to 0.008-001wt%, thereby refining the grains and controlling the inclusions at a lower level.

[0032] As a preferred technical solution of the present invention, in step (II), the diameter of the calcium iron cored wire is 8-13 mm, for example, it can be 8 mm, 9 mm, 10 mm, 11 mm, 12 mm or 13 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] The feeding ratio of the calcium iron cored wire is: 0.30-1.5 kg of calcium iron cored wire per ton of molten steel, for example, it can be 0.3 kg, 0.4 kg, 0.5 kg, 0.6 kg, 0.7 kg, 0.8 kg, 0.9 kg, 1.0 kg, 1.1 kg, 1.2 kg, 1.3 kg, 1.4 kg or 1.5 kg, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] The wire feeding speed of the calcium-iron cored wire is 100-150m / min, for example, it can be 100m / min, 105m / min, 110m / min, 115m / min, 120m / min, 125m / min, 130m / min, 135m / min, 140m / min, 145m / min or 150m / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] The present invention adopts calcium iron cored wire to replace the traditional calcium wire. This is because the molten steel and the calcium wire will react violently to produce splashing, thereby causing a large area of ​​molten steel to be exposed. At this time, the average temperature of the molten steel is 1625-1630°C, which will cause a large amount of nitrogen increase. The calcium iron cored wire is used to replace the traditional calcium wire. The calcium treatment of the molten steel can effectively inhibit the splashing and exposure of the molten steel, thereby achieving the effect of inhibiting nitrogen increase.

[0036] As a preferred technical solution of the present invention, in step (II), the duration of the single argon blowing is ≥2 min, for example, it can be 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min or 12 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] The argon flow rate of the first argon blowing is 10-20Nm 2 / h, for example, 10Nm 2 / h、11Nm 2 / h、12Nm 2 / h、13Nm 2 / h、14Nm 2 / h、15Nm 2 / h、16Nm 2 / h、17Nm2 / h、18Nm 2 / h、19Nm 2 / h or 20Nm 2 / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] The argon pressure of the first argon blowing is 0.2-0.3 MPa, for example, it can be 0.2 MPa, 0.21 MPa, 0.22 MPa, 0.23 MPa, 0.24 MPa, 0.25 MPa, 0.26 MPa, 0.27 MPa, 0.28 MPa, 0.29 MPa or 0.3 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] The duration of the secondary argon blowing is ≥ 3 min, for example, it can be 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] The argon flow rate of the secondary argon blowing is 1-8Nm 2 / h, for example, 1Nm 2 / h, 2Nm 2 / h、3Nm 2 / h, 4Nm 2 / h、5Nm 2 / h、6Nm 2 / h、7Nm 2 / h or 8Nm 2 / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0041] The argon pressure of the secondary argon blowing is 0.08-0.1 MPa, for example, it can be 0.08 MPa, 0.082 MPa, 0.084 MPa, 0.086 MPa, 0.088 MPa, 0.09 MPa, 0.092 MPa, 0.094 MPa, 0.096 MPa, 0.098 MPa or 0.1 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] The duration of the three argon purges is ≥ 6 min, for example, it can be 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] The argon flow rate of the three argon blowing is 1-8Nm 2 / h, for example, 1Nm 2 / h, 2Nm 2 / h、3Nm 2 / h, 4Nm 2 / h、5Nm 2 / h、6Nm 2 / h、7Nm 2 / h or 8Nm 2 / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] The argon pressure of the three argon blowings is 0.08-0.1 MPa, for example, it can be 0.08 MPa, 0.082 MPa, 0.084 MPa, 0.086 MPa, 0.088 MPa, 0.09 MPa, 0.092 MPa, 0.094 MPa, 0.096 MPa, 0.098 MPa or 0.1 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] After the three argon blowing processes are completed, the temperature of the molten steel is controlled to be 1580-1590°C, for example, it can be 1580°C, 1581°C, 1582°C, 1583°C, 1584°C, 1585°C, 1586°C, 1587°C, 1588°C, 1589°C or 1590°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] The present invention feeds aluminum wire and calcium iron cored wire into molten steel during the slag washing and refining process, so that the molten steel undergoes an alloying reaction, generating a large amount of gas, alloy and corrosive inclusions. The blowing of argon gas causes part of the gas inclusions and deoxidation inclusions to float and pulverize through eddy current shearing, thereby better removing the inclusions in the molten steel. The present invention particularly adopts three times of argon blowing, and through staged gas volume control and pressure control, the inclusions are further floated, absorbed and removed.

[0047] As a preferred technical solution of the present invention, in step (III), the water-cooled crystallizer is cooled by circulating water, and before the molten steel is injected into the water-cooled crystallizer, the outlet water temperature of the circulating water is controlled by a constant temperature control device to be 35-45°C, for example, it can be 35°C, 35.5°C, 36°C, 36.5°C, 37°C, 37.5°C, 38°C, 38.5°C, 39°C, 39.5°C or 40°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] As a preferred technical solution of the present invention, in step (III), during the solidification process of the molten steel in the water-cooled crystallizer, the molten steel in the water-cooled crystallizer is electromagnetically stirred by an electromagnetic stirring device.

[0049] The output current of the electromagnetic stirring device is 220-300A, for example, it can be 220A, 230A, 240A, 250A, 260A, 270A, 280A, 290A or 300A, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] The output frequency of the electromagnetic stirring device is 2-6 Hz, for example, 2.0 Hz, 2.5 Hz, 3.0 Hz, 3.5 Hz, 4.0 Hz, 4.5 Hz, 5.0 Hz, 5.5 Hz or 6.0 Hz, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0051] The electromagnetic stirring process includes: rotating the molten steel forward, stopping and reversing for 5 seconds each, and continuously circulating.

[0052] The present invention performs electromagnetic stirring on molten steel during the continuous casting process. Under the premise of not polluting the molten steel, the electromagnetic stirring can improve the structure in the shell of the continuous casting billet, improve the strength of the continuous casting billet, reduce the influence of crack sensitivity on the billet shell, optimize the quality requirements of product performance, improve the continuous casting production efficiency, reduce the cracks of the continuous casting billet, increase the ratio of fine equiaxed crystals in the continuous casting billet, improve the requirements for the uniformity of the structure of the continuous casting billet, and reduce the production cost of the enterprise.

[0053] After the molten steel enters the water-cooled crystallizer, as the solidification process of the molten steel proceeds, solute elements such as C, O, N and H in the interdendritic liquid phase are gradually enriched. When the C and O elements are enriched to a certain extent, exceeding the CO equilibrium value, a carbon-oxygen reaction will occur to generate CO gas; at the same time, when the N and H elements are enriched to a certain extent, nitrogen and hydrogen will also be formed. As the solidification process proceeds further, these gases gradually gather and the gas pressure gradually increases. During the continuous casting solidification process, if the oxygen content in the molten steel is controlled to be too high, CO gas will continue to precipitate as the temperature decreases. When the molten steel solidifies to form a hard shell, the last precipitated gas cannot overflow and is retained in the continuous casting billet, forming surface bubbles that grow together with the columnar crystals. Therefore, the present invention performs electromagnetic stirring on the molten steel to cause all the gases generated in the molten steel to precipitate before the molten steel solidifies to form a hard shell.

[0054] As a preferred technical solution of the present invention, in step (III), the pulling speed is 2.0-3.5 m / min, for example, it can be 2.0 m / min, 2.1 m / min, 2.2 m / min, 2.3 m / min, 2.4 m / min, 2.5 m / min, 2.6 m / min, 2.7 m / min, 2.8 m / min, 2.9 m / min, 3.0 m / min, 3.1 m / min, 3.2 m / min, 3.3 m / min, 3.4 m / min or 3.5 m / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Exemplarily, the present invention provides a method for producing H08Mn welding rod steel based on converter direct loading and pre-slag washing, and the H08Mn welding rod steel production method comprises the following steps:

[0056] (1) Converter smelting: molten iron from a blast furnace is poured into a converter for smelting to form molten steel. The sulfur content of the molten iron from the blast furnace before entering the converter is ≤0.035wt%, and the phosphorus content is ≤0.150wt%. When the carbon content in the molten steel is 0.04-0.07wt%, the phosphorus content is ≤0.022wt%, and the sulfur content is ≤0.023wt%, the smelting end point is reached. The molten steel in the converter is poured into a ladle for slag tapping. The temperature of the molten steel during slag tapping is 1620-168 0℃; add calcium-aluminum pre-melted refined slag to the ladle to wash the molten steel at the beginning of tapping, and add 2-8kg of pre-melted refined slag per ton of molten steel; when the slag blocking tapping is 1 / 3, add medium-carbon ferromanganese alloy or low-carbon ferromanganese alloy to the molten steel, and add 12-14kg of medium-carbon ferromanganese alloy or low-carbon ferromanganese alloy per ton of molten steel; add lime powder and aluminum particles to the ladle after tapping is completed; add 2-3kg of lime powder per ton of molten steel, and add 0.1-1kg of aluminum particles per ton of molten steel;

[0057] (2) Slag washing refining: 10-20Nm from the bottom of the ladle2 / h, 0.2-0.3MPa argon is continuously blown into the molten steel for a first argon blowing. After blowing argon for ≥2min, the molten steel is oxygenated and the temperature is measured. According to the oxygen determination result, an aluminum wire with a diameter of 8-13mm is fed into the molten steel at a speed of 100-150m / min to adjust the oxygen content in the molten steel to 10-80ppm. 0.20-1kg of aluminum wire is fed per ton of molten steel. Subsequently, the aluminum wire is again blown from the bottom of the ladle at a speed of 1-8Nm 2 / h flow rate into the molten steel 0.08-0.1MPa argon gas for secondary argon blowing, after blowing argon for ≥3min, feed 8-13mm diameter calcium iron cored wire into the molten steel at a speed of 100-150m / min for calcium treatment, feed 0.3-1.5kg calcium iron cored wire per ton of molten steel, after all the calcium wire is fed, it is again blown from the bottom of the ladle at a speed of 1-8Nm 2 / h, continuously blow 0.08-0.1MPa argon into the molten steel for ≥6min for three times. After the three times of blowing, control the temperature of the molten steel to 1580-1590℃;

[0058] (3) Continuous casting: Pour molten steel into a tundish, and flow into a water-cooled crystallizer through the tundish, and cool the molten steel in the water-cooled crystallizer by circulating water at 35-45°C; during the solidification process of the molten steel in the water-cooled crystallizer, the molten steel in the water-cooled crystallizer is rotated forward, stopped, and reversed for 5 seconds each by an electromagnetic stirring device with an output frequency of 2-6 Hz and an output current of 220-300 A, and circulated and stirred to make the molten steel more uniform; the continuous casting billet with a hard shell solidified on the outer surface is continuously pulled out from the bottom outlet of the water-cooled crystallizer at a speed of 2.0-3.5 m / min and sprayed with water for cooling, and cut into billets after complete solidification to obtain the H08Mn welding rod steel.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] The present invention adopts a converter direct-to-steam process route combined with pre-melted refined slag washing, and uses pre-melted refined slag to modify the molten steel during the slag blocking and steel-making process, which can ensure that the steel slag is quickly slag-formed; then, through argon station calcium treatment and argon soft blowing and other processes, it is ensured that the molten steel meets the conditions for casting on the stage, and the stable casting of continuous casting molten steel is achieved, so as to achieve the purpose of stabilizing the quality of the molten steel. Compared with the LF refining process, the slag washing and refining process adopted in the present invention can avoid the secondary oxygen and nitrogen absorption of the molten steel during the refining process, and improve the castability of the molten steel. The advantage of the production process provided by the present invention is that it can achieve precise endpoint control and steel-making slag modification, and the production cost can be significantly reduced, and the production cost can be reduced by 25-40 yuan / ton. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 A process flow chart of the production of H08Mn welding rod steel provided in Examples 1-5 of the present invention;

[0062] Figure 2 This is an optical picture of the as-cast structure of the H08Mn welding rod steel sample prepared in Example 1 of the present invention;

[0063] Figure 3 This is an optical picture of the as-cast structure of the H08Mn welding rod steel sample prepared in the comparative example of the present invention. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limitations on the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments recorded herein.

[0065] Example 1

[0066] This embodiment provides a method for producing H08Mn welding rod steel based on converter direct ascent and pre-slag washing, such as Figure 1 As shown, the H08Mn welding rod steel production method comprises the following steps:

[0067] (1) Converter smelting: molten iron from a blast furnace is injected into a converter for smelting to form molten steel, wherein the sulfur content of the molten iron from the blast furnace before entering the converter is 0.02wt% and the phosphorus content is 0.13wt%; when the carbon content, phosphorus content and sulfur content of the molten steel are 0.04wt%, 0.01wt% and 0.01wt%, the smelting end point is reached, and the molten steel in the converter is injected into a ladle for slag blocking and tapping, and the temperature of the molten steel during slag blocking and tapping is 1620°C; at the beginning of tapping, calcium-aluminum pre-melted refined slag is added to the ladle to wash the molten steel, and 2kg of pre-melted refined slag is added per ton of molten steel; when the slag blocking and tapping are carried out to 1 / 3, medium-carbon ferromanganese alloy is added to the molten steel, and 12kg of medium-carbon ferromanganese alloy is added per ton of molten steel; after tapping is completed, lime powder and aluminum particles are added to the ladle; 2kg of lime powder is added per ton of molten steel, and 0.1kg of aluminum particles are added per ton of molten steel;

[0068] (2) Slag washing and refining: 10Nm from the bottom of the ladle 2 / h, 0.2MPa argon gas was continuously blown into the molten steel for a single blow. After blowing argon for 2 minutes, the molten steel was oxygenated and the temperature was measured. According to the oxygen determination result, an aluminum wire with a diameter of 8mm was fed into the molten steel at a speed of 100m / min to adjust the oxygen content in the molten steel to 80ppm. 0.2kg of aluminum wire was fed per ton of molten steel. Subsequently, 1Nm 2 / h, 0.08MPa argon was blown into the molten steel for secondary argon blowing. After blowing argon for 3 minutes, 8mm diameter calcium iron cored wire was fed into the molten steel at a speed of 100m / min for calcium treatment. 0.3kg calcium iron cored wire was fed per ton of molten steel. After all the calcium wire was fed, it was blown again from the bottom of the ladle at a speed of 1Nm 2 / h, 0.08MPa argon gas was continuously blown into the molten steel for 6 minutes for three times. After the three times of blowing, the temperature of the molten steel was controlled to be 1580℃;

[0069] (3) Continuous casting: Pour molten steel into a tundish, and flow into a water-cooled crystallizer through the tundish. The molten steel in the water-cooled crystallizer is cooled by circulating water at 35°C. During the solidification process of the molten steel in the water-cooled crystallizer, the molten steel in the water-cooled crystallizer is rotated forward, stopped, and reversed for 5 seconds each by an electromagnetic stirring device with an output frequency of 2 Hz and an output current of 220 A, and circulated and stirred to make the molten steel more uniform. The continuous casting billet with a hard shell solidified on the outer surface is continuously pulled out from the bottom outlet of the water-cooled crystallizer at a speed of 2 m / min and sprayed with water for cooling. After complete solidification, it is cut into billets to obtain the H08Mn welding rod steel.

[0070] Example 2

[0071] This embodiment provides a method for producing H08Mn welding rod steel based on converter direct ascent and pre-slag washing, such as Figure 1 As shown, the H08Mn welding rod steel production method comprises the following steps:

[0072] (1) Converter smelting: blast furnace molten iron is injected into a converter for smelting to form molten steel, the sulfur content of the blast furnace molten iron before entering the furnace is 0.028wt%, and the phosphorus content is 0.135wt%; when the carbon content, phosphorus content and sulfur content in the molten steel are 0.05wt%, 0.015wt% and 0.015wt%, the smelting end point is reached, the molten steel in the converter is injected into a ladle for slag blocking and tapping, and the molten steel temperature during slag blocking and tapping is 1640°C; at the beginning of tapping, calcium-aluminum pre-melted refined slag is added to the ladle to wash the molten steel, and 4kg of pre-melted refined slag is added per ton of molten steel; when the slag blocking and tapping are carried out to 1 / 3, medium-carbon ferromanganese alloy is added to the molten steel, and 12.5kg of medium-carbon ferromanganese alloy is added per ton of molten steel; after tapping is completed, lime powder and aluminum particles are added to the ladle; 2.2kg of lime powder is added per ton of molten steel, and 0.3kg of aluminum particles are added per ton of molten steel;

[0073] (2) Slag washing and refining: 12Nm from the bottom of the ladle 2 / h, 0.22MPa argon gas was continuously blown into the molten steel for a single blow. After blowing argon for 3 minutes, the molten steel was oxygenated and the temperature was measured. According to the oxygen determination result, an aluminum wire with a diameter of 10mm was fed into the molten steel at a speed of 110m / min to adjust the oxygen content in the molten steel to 60ppm. 0.4kg of aluminum wire was fed per ton of molten steel. Subsequently, 3Nm 2 / h flow rate of 0.085MPa argon gas was blown into the molten steel for secondary argon blowing. After blowing argon for 4 minutes, calcium iron cored wire with a diameter of 10mm was fed into the molten steel at a speed of 110m / min for calcium treatment. 0.8kg of calcium iron cored wire was fed per ton of molten steel. After all the calcium wire was fed, it was again blown from the bottom of the ladle at a speed of 3Nm 2 / h, 0.085MPa argon gas was continuously blown into the molten steel for 7 minutes for three times. After the three times of blowing, the temperature of the molten steel was controlled to be 1582℃;

[0074] (3) Continuous casting: Pour molten steel into a tundish, and flow into a water-cooled crystallizer through the tundish. The molten steel in the water-cooled crystallizer is cooled by circulating water at 36°C. During the solidification process of the molten steel in the water-cooled crystallizer, the molten steel in the water-cooled crystallizer is rotated forward, stopped, and reversed for 5 seconds each by an electromagnetic stirring device with an output frequency of 3 Hz and an output current of 250 A, and circulated and stirred to make the molten steel more uniform. The continuous casting billet with a hard shell solidified on the outer surface is continuously pulled out from the bottom outlet of the water-cooled crystallizer at a speed of 2.5 m / min and sprayed with water for cooling. After complete solidification, it is cut into billets to obtain the H08Mn welding rod steel.

[0075] Example 3

[0076] This embodiment provides a method for producing H08Mn welding rod steel based on converter direct ascent and pre-slag washing, such as Figure 1 As shown, the H08Mn welding rod steel production method comprises the following steps:

[0077] (1) Converter smelting: molten iron from a blast furnace is injected into a converter for smelting to form molten steel. The sulfur content of the molten iron from the blast furnace before entering the converter is 0.03wt% and the phosphorus content is 0.14wt%; when the carbon content, phosphorus content and sulfur content in the molten steel are 0.055wt%, 0.018wt% and 0.018wt%, the smelting end point is reached, and the molten steel in the converter is injected into a ladle for slag blocking and tapping. The temperature of the molten steel during slag blocking and tapping is 1660°C; at the beginning of tapping, calcium-aluminum pre-melted refined slag is added to the ladle to wash the molten steel, and 6kg of pre-melted refined slag is added per ton of molten steel; when the slag blocking and tapping are carried out to 1 / 3, medium-carbon ferromanganese alloy is added to the molten steel, and 13kg of medium-carbon ferromanganese alloy is added per ton of molten steel; after tapping is completed, lime powder and aluminum particles are added to the ladle; 2.5kg of lime powder is added per ton of molten steel, and 0.5kg of aluminum particles are added per ton of molten steel;

[0078] (2) Slag washing and refining: 15Nm from the bottom of the ladle 2 / h, 0.25MPa argon gas was continuously blown into the molten steel for a single blow. After blowing argon for 4 minutes, the molten steel was oxygenated and the temperature was measured. According to the oxygen determination result, an aluminum wire with a diameter of 11mm was fed into the molten steel at a speed of 120m / min to adjust the oxygen content in the molten steel to 40ppm. 0.6kg of aluminum wire was fed per ton of molten steel. Subsequently, 5Nm 2 / h, 0.09MPa argon gas was blown into the molten steel for secondary argon blowing. After blowing argon for 5 minutes, 11mm diameter calcium iron cored wire was fed into the molten steel at a speed of 120m / min for calcium treatment. 1kg of calcium iron cored wire was fed into each ton of molten steel. After all the calcium wire was fed, it was blown again from the bottom of the ladle at a speed of 5Nm 2 / h, 0.09MPa argon gas was continuously blown into the molten steel for 8 minutes for three times. After the three times of blowing argon, the temperature of the molten steel was controlled to be 1585℃;

[0079] (3) Continuous casting: Pour molten steel into a tundish, and flow into a water-cooled crystallizer through the tundish. The molten steel in the water-cooled crystallizer is cooled by circulating water at 37°C. During the solidification process of the molten steel in the water-cooled crystallizer, the molten steel in the water-cooled crystallizer is rotated forward, stopped, and reversed for 5 seconds each by an electromagnetic stirring device with an output frequency of 4 Hz and an output current of 260 A, and circulated and stirred to make the molten steel more uniform. The continuous casting billet with a hard shell solidified on the outer surface is continuously pulled out from the bottom outlet of the water-cooled crystallizer at a speed of 2.8 m / min and sprayed with water for cooling. After complete solidification, it is cut into billets to obtain the H08Mn welding rod steel.

[0080] Example 4

[0081] This embodiment provides a method for producing H08Mn welding rod steel based on converter direct ascent and pre-slag washing, such as Figure 1 As shown, the H08Mn welding rod steel production method comprises the following steps:

[0082] (1) Converter smelting: molten iron from a blast furnace is injected into a converter for smelting to form molten steel, wherein the sulfur content of the molten iron from the blast furnace before entering the converter is 0.032wt% and the phosphorus content is 0.145wt%; when the carbon content, phosphorus content and sulfur content of the molten steel are 0.06wt%, 0.02wt% and 0.02wt%, the smelting end point is reached, and the molten steel in the converter is injected into a ladle for slag blocking and tapping, and the temperature of the molten steel during slag blocking and tapping is 1670°C; at the beginning of tapping, calcium-aluminum pre-melted refined slag is added to the ladle to wash the molten steel, and 7kg of pre-melted refined slag is added per ton of molten steel; when the slag blocking and tapping are carried out to 1 / 3, medium-carbon ferromanganese alloy is added to the molten steel, and 13.5kg of medium-carbon ferromanganese alloy is added per ton of molten steel; after tapping is completed, lime powder and aluminum particles are added to the ladle; 2.8kg of lime powder is added per ton of molten steel, and 0.7kg of aluminum particles are added per ton of molten steel;

[0083] (2) Slag washing and refining: 18Nm from the bottom of the ladle 2 / h, 0.28MPa argon gas was continuously blown into the molten steel for a single blow. After blowing argon for 5 minutes, the molten steel was oxygenated and the temperature was measured. According to the oxygen determination result, an aluminum wire with a diameter of 12mm was fed into the molten steel at a speed of 130m / min to adjust the oxygen content in the molten steel to 20ppm. 0.8kg of aluminum wire was fed per ton of molten steel. Subsequently, 6Nm 2 / h flow rate of 0.095MPa argon gas was blown into the molten steel for secondary argon blowing. After blowing argon for 6 minutes, calcium iron cored wire with a diameter of 12mm was fed into the molten steel at a speed of 130m / min for calcium treatment. 1.2kg of calcium iron cored wire was fed into the molten steel for each ton of molten steel. After all the calcium wire was fed, it was again blown from the bottom of the ladle at a speed of 6Nm 2 / h, 0.095MPa argon gas was continuously blown into the molten steel for 9 minutes for three times. After the three times of blowing, the temperature of the molten steel was controlled to be 1588℃;

[0084] (3) Continuous casting: Pour molten steel into a tundish, and flow into a water-cooled crystallizer through the tundish. The molten steel in the water-cooled crystallizer is cooled by circulating water at 38°C. During the solidification process of the molten steel in the water-cooled crystallizer, the molten steel in the water-cooled crystallizer is rotated forward, stopped, and reversed for 5 seconds each by an electromagnetic stirring device with an output frequency of 5 Hz and an output current of 280 A, and circulated and stirred to make the molten steel more uniform. The continuous casting billet with a hard shell solidified on the outer surface is continuously pulled out from the bottom outlet of the water-cooled crystallizer at a speed of 3 m / min and sprayed with water for cooling. After complete solidification, it is cut into billets to obtain the H08Mn welding rod steel.

[0085] Example 5

[0086] This embodiment provides a method for producing H08Mn welding rod steel based on converter direct ascent and pre-slag washing, such as Figure 1 As shown, the H08Mn welding rod steel production method comprises the following steps:

[0087] (1) Converter smelting: molten iron from a blast furnace is injected into a converter for smelting to form molten steel, wherein the sulfur content of the molten iron from the blast furnace before entering the converter is 0.035wt% and the phosphorus content is 0.15wt%; when the carbon content, phosphorus content and sulfur content of the molten steel are 0.07wt%, 0.022wt% and 0.023wt%, the smelting end point is reached, and the molten steel in the converter is injected into a ladle for slag blocking and tapping, and the temperature of the molten steel during slag blocking and tapping is 1680°C; at the beginning of tapping, calcium-aluminum pre-melted refined slag is added to the ladle to wash the molten steel, and 8kg of pre-melted refined slag is added per ton of molten steel; when the slag blocking and tapping are carried out to 1 / 3, medium-carbon ferromanganese alloy is added to the molten steel, and 14kg of medium-carbon ferromanganese alloy is added per ton of molten steel; after tapping is completed, lime powder and aluminum particles are added to the ladle; 3kg of lime powder is added per ton of molten steel, and 1kg of aluminum particles is added per ton of molten steel;

[0088] (2) Slag washing and refining: 20Nm from the bottom of the ladle 2 / h, 0.3MPa argon gas was continuously blown into the molten steel for a single blow. After blowing argon for 6 minutes, the molten steel was oxygenated and the temperature was measured. According to the oxygen determination result, an aluminum wire with a diameter of 13mm was fed into the molten steel at a speed of 150m / min to adjust the oxygen content in the molten steel to 10ppm. 1kg of aluminum wire was fed per ton of molten steel. Subsequently, 8Nm 2 / h flow rate into the molten steel to blow argon gas of 0.1MPa for secondary argon blowing. After blowing argon for 7 minutes, calcium iron cored wire with a diameter of 13mm was fed into the molten steel at a speed of 150m / min for calcium treatment. 1.5kg of calcium iron cored wire was fed per ton of molten steel. After all the calcium wire was fed, it was blown again from the bottom of the ladle at a speed of 8Nm 2 / h, 0.1MPa argon gas was continuously blown into the molten steel for 10 minutes for three times. After the three times of blowing, the temperature of the molten steel was controlled to be 1590℃;

[0089] (3) Continuous casting: Pour molten steel into a tundish, and flow into a water-cooled crystallizer through the tundish. The molten steel in the water-cooled crystallizer is cooled by circulating water at 40°C. During the solidification process of the molten steel in the water-cooled crystallizer, the molten steel in the water-cooled crystallizer is rotated forward, stopped, and reversed for 5 seconds each by an electromagnetic stirring device with an output frequency of 6 Hz and an output current of 300 A, and circulated and stirred to make the molten steel more uniform. The continuous casting billet with a hard shell solidified on the outer surface is continuously pulled out from the bottom outlet of the water-cooled crystallizer at a speed of 3.5 m / min and sprayed with water for cooling. After complete solidification, it is cut into billets to obtain the H08Mn welding rod steel.

[0090] Comparative Example

[0091] This comparative example is Example 1 provided in the patent publication CN112280923A for a smelting method of welding rod steel H08Mn.

[0092] The as-cast structures of the H08Mn welding rod steel samples prepared in Example 1 and the comparative example were observed using an optical microscope, and the following results were obtained: Figure 2 (Example 1) and Figure 3 The optical picture shown in (Comparative Example) is Figure 2 and Figure 3 By comparison, it can be seen that Figure 2 The casting microstructure is more refined. Figure 2 The granular bainite ratio in the central area Figure 3 Significantly reduced, and Figure 2 The ferrite content in the steel has increased, and it has good comprehensive properties.

[0093] The yield strength, tensile strength and area reduction ratio of the H08Mn welding rod steel prepared in Examples 1-5 were tested. The test results are shown in Table 1.

[0094] Table 1

[0095]

[0096]

[0097] It can be seen from the data in Table 1 that the various properties of the H08Mn welding rod steel prepared in Example 1 of the present invention are better than those of the comparative example.

[0098] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for producing H08Mn welding rod steel based on converter direct ascent and pre-slag washing, characterized in that: The H08Mn welding rod steel production method comprises the following steps: (I) Converter smelting: molten iron from a blast furnace is poured into a converter for smelting to form molten steel. When the carbon content, phosphorus content and sulfur content in the molten steel reach the target values, the smelting end point is reached. The molten steel in the converter is poured into a ladle for slag blocking and tapping. At the beginning of tapping, pre-melted refined slag is added to the ladle to wash the molten steel. After tapping, lime powder and aluminum particles are added to the ladle. The pre-melted refined slag is calcium-aluminum pre-melted refined slag; the addition ratio of the pre-melted refined slag is: 2-8 kg of pre-melted refined slag is added per ton of molten steel; The temperature of the molten steel during the slag blocking and steel tapping is 1620-1680°C; The lime powder is added in a proportion of 2-3 kg lime powder per ton of molten steel; The addition ratio of the aluminum particles is: 0.1-1 kg of aluminum particles per ton of molten steel; When the slag blocking and steel tapping is completed to 1 / 3, add medium carbon ferromanganese alloy or low carbon ferromanganese alloy into the molten steel; The addition ratio of the medium carbon ferromanganese alloy or the low carbon ferromanganese alloy is: 12-14 kg of the medium carbon ferromanganese alloy or the low carbon ferromanganese alloy is added per ton of molten steel; (II) Slag washing and refining: argon gas is continuously blown into the molten steel from the bottom of the ladle for a first argon blow. After blowing argon for a period of time, the molten steel is oxygenated and the temperature is measured. According to the oxygen determination result, aluminum wire is fed into the molten steel to adjust the oxygen content in the molten steel to the target value. Subsequently, argon gas is blown into the molten steel from the bottom of the ladle for a second argon blow. After blowing argon for a period of time, calcium iron cored wire is fed into the molten steel for calcium treatment. After all the calcium wires are fed, argon gas is continuously blown into the molten steel from the bottom of the ladle for a third argon blow. The diameter of the aluminum wire is 8-13 mm; the feeding ratio of the aluminum wire is: 0.20-1 kg of aluminum wire per ton of molten steel; the wire feeding speed of the aluminum wire is 100-150 m / min; the target value of the oxygen content in the molten steel is 10-80 ppm; the diameter of the calcium iron cored wire is 8-13 mm; the feeding ratio of the calcium iron cored wire is: 0.30-1.5 kg of calcium iron cored wire per ton of molten steel; the wire feeding speed of the calcium iron cored wire is 100-150 m / min; (III) Continuous casting: pouring molten steel into a tundish, and flowing into a water-cooled crystallizer through the tundish. After the molten steel solidifies into a hard shell, it is continuously pulled out from the bottom outlet of the water-cooled crystallizer and sprayed with water for cooling. After it is completely solidified, it is cut into billets to obtain the H08Mn welding rod steel; In the step (III), the water-cooled crystallizer is cooled by circulating water, and before the molten steel is injected into the water-cooled crystallizer, the outlet temperature of the circulating water is controlled to be 35-45° C. by a constant temperature control device; During the solidification process of the molten steel in the water-cooled crystallizer, the molten steel in the water-cooled crystallizer is electromagnetically stirred by an electromagnetic stirring device; the output current of the electromagnetic stirring device is 220-300A; the output frequency of the electromagnetic stirring device is 2-6Hz; the electromagnetic stirring process includes: rotating the molten steel forward, stopping and reversing for 5 seconds each, and continuously circulating.

2. The method for producing H08Mn welding rod steel according to claim 1, characterized in that: In step (I), the sulfur content of the molten iron in the blast furnace before entering the furnace is ≤0.035wt%, and the phosphorus content is ≤0.150wt%; When the smelting end point is reached, the carbon content in the molten steel is 0.04-0.07wt%, the phosphorus content is ≤0.022wt%, and the sulfur content is ≤0.023wt%.

3. The method for producing H08Mn welding rod steel according to claim 1, characterized in that: In step (II), the duration of the argon blowing is ≥ 2 min; The argon flow rate of the first argon blowing is 10-20Nm 2 / h; The argon pressure of the first argon blowing is 0.2-0.3MPa; The duration of the secondary argon blowing is ≥3min; The argon flow rate of the secondary argon blowing is 1-8Nm 2 / h; The argon pressure of the secondary argon blowing is 0.08-0.1MPa; The duration of the three argon blowings is ≥ 6 min; The argon flow rate of the three argon blowing is 1-8Nm 2 / h; The argon pressure of the three argon blowings is 0.08-0.1MPa; After the three times of argon blowing are completed, the temperature of the molten steel is controlled to be 1580-1590°C.

4. The method for producing H08Mn welding rod steel according to claim 1, characterized in that: In step (III), the pulling speed is 2.0-3.5 m / min.

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