Process method for smelting wiredrawing steel in converter

Abstract

The invention provides a process method for smelting wire-drawing steel by a converter, which comprises the following steps of: 1, adding molten iron and scrap steel into the converter, and adjusting the proportion of the molten iron and the scrap steel according to the requirement of tapping temperature; 2, high-pressure oxygen is blown into the molten iron and the waste steel to conduct an oxidation-reduction reaction on the molten iron and the waste steel; 3, tapping at the blowing end point, adjusting argon supply into a strong blowing mode during tapping, and performing a deoxidation alloying process during tapping; and 4, after the component concentration distribution and the temperature distribution are adjusted to be qualified, the molten steel is transported to a continuous casting workshop section for casting. According to the technological method for smelting the wiredrawing steel Q195L through the converter, fine adjustment is conducted in the weakening argon station, the fine adjustment link is moved forwards to the blowing end point steel tapping and deoxidation alloying process, inclusions in the steel are obviously reduced, and meanwhile the component requirement of an original production technology for the wiredrawing steel Q195L can still be met.

Description

Technical Field

[0001] The invention relates to the technical field of converter steelmaking in steel production, and in particular to a process method for smelting wire drawing steel in a converter. Background Art

[0002] In the steelmaking industry, low-carbon wire drawing steel, referred to as wire drawing steel, is widely used in the metal products industry. Q195L steel is the representative type of wire drawing steel. Q195L is widely used due to its low strength and good elongation. It is used in wire drawing to produce galvanized iron wire, filter screen, wire mesh, carton flat wire, nails and other hardware products, with a broad market and good economic and social benefits.

[0003] The existing Q195L drawing steel production generally includes several steps: adding molten iron and scrap steel into the converter - tapping at the end of blowing - deoxidation and alloying - fine-tuning at the argon station - continuous casting.

[0004] Specifically, molten iron and scrap steel that meet the requirements of converter smelting are added to the converter through a crane, and then high-pressure oxygen is blown into the molten iron and scrap steel to carry out oxidation-reduction reaction on the molten iron and scrap steel; when the carbon, sulfur, phosphorus and other elements in the molten iron and the temperature meet the process requirements (that is, the blowing reaches the end point), the supply of oxygen is stopped, and the oxidized liquid metal is poured from the converter into the ladle (steel tapping), and alloys (silicon-aluminum-calcium, silicon-manganese, aluminum blocks) are added during the steel tapping process for deoxidation and alloying, and the alloying must meet the alloy composition process requirements of the steel grade; after completion, the molten steel enters the argon blowing station for argon blowing treatment to make the component concentration distribution and temperature distribution uniform. When the temperature distribution and component concentration distribution meet the requirements, the ladle is transported to the continuous casting for casting to produce continuous billets that meet the needs.

[0005] Table 0Q195L ingredient control requirements

[0006]

[0007] The present invention provides a new process method for smelting wire drawing steel Q195L in a converter, attempting to improve the properties of the wire drawing steel smelted in the converter. Summary of the invention

[0008] The present invention provides a new process method for smelting wire drawing steel Q195L in a converter, attempting to improve the properties of the wire drawing steel smelted in the converter.

[0009] The invention provides a process method for smelting wire drawing steel in a converter, comprising: step 1: adding molten iron and scrap steel into a converter, wherein the ratio of the molten iron to the scrap steel is adjusted according to the requirement of the steel tapping temperature; step 2: blowing high-pressure oxygen into the molten iron and the scrap steel to carry out oxidation-reduction reaction on the molten iron and the scrap steel; step 3: tapping the steel at the end of blowing, adjusting the argon supply to a strong blowing mode when tapping the steel, and carrying out a deoxidation alloying process when tapping the steel; and step 4: after the component concentration distribution and the temperature distribution are adjusted to be qualified, transporting the molten steel to a continuous casting section for casting.

[0010] Furthermore, in step 3, the strong blowing mode is such that the pressure is maintained at 0.4-0.6 MPa and the flow rate is 150-250 NL / min.

[0011] Furthermore, in the deoxidation alloying process, the types and order of added materials are silicon manganese, aluminum blocks, and silicon aluminum calcium.

[0012] Furthermore, for the heat of slag discharge during steel tapping, silicon carbide or calcium carbide is added at the end of steel tapping to diffuse and deoxidize the slag to ensure the physical and chemical properties of the slag.

[0013] Furthermore, for the heat of steel tapping and slag removal, the argon pressure is maintained at 0.4-0.6MPa at the end of steel tapping, and the flow rate is 150NL / min, achieving strong blowing for 3-4 minutes or switching to soft blowing.

[0014] Furthermore, the flow rate and pressure of the soft blow are 0.4MPa, 50-100NL / min.

[0015] Furthermore, the soft blowing time is greater than 10-12 minutes.

[0016] Furthermore, the ladle must be well ventilated before adding silicon carbide or calcium carbide.

[0017] Furthermore, the final carbon (C) content is ≤0.06% when the steel is tapped at the final stage of blowing.

[0018] The process method for smelting wire drawing steel Q195L in a converter provided by the present invention weakens the fine adjustment of the argon station and moves the fine adjustment link forward to the steel tapping and deoxidation alloying process at the end of blowing, so that the inclusions in the steel are significantly reduced, while still meeting the component requirements of the original production process for the wire drawing steel Q195L, the center crack is reduced, the elongation is increased, the wire breakage rate is reduced, and good wire drawing properties are embodied. DETAILED DESCRIPTION

[0019] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the following detailed description is given in conjunction with the embodiments.

[0020] The embodiment of the present invention provides a process method for smelting wire drawing steel in a converter, comprising: step 1: adding molten iron and scrap steel into a converter, wherein the ratio of the molten iron to the scrap steel is adjusted according to the requirement of the steel tapping temperature; step 2: blowing high-pressure oxygen into the molten iron and the scrap steel to carry out an oxidation-reduction reaction on the molten iron and the scrap steel; step 3: tapping the steel at the end of blowing, and adjusting the argon supply to a strong blowing mode when tapping the steel, and performing a deoxidation and alloying process when tapping the steel; and step 4: after the component concentration distribution and the temperature distribution are adjusted to be qualified, transporting the molten steel to a continuous casting section for casting.

[0021] During the final steel tapping process of blowing, the final carbon (C) content is controlled from the original ≤0.04% to (C) ≤0.06%. This is because the product of [C] [O] is different at different temperatures, and steel tapping is a temperature drop process. According to the reaction formula: [C] + [O] = {CO} Using the carbon oxygen product formula: Since the steel tapping process is a temperature drop process, the carbon-oxygen balance is destroyed by temperature drop, and the carbon-oxygen reaction produces CO to stir the molten steel, promote the floating of deoxidized products, etc., and purify the molten steel. At the same time, due to the carbon-oxygen reaction, the carbon content can be further reduced, so the end point carbon (C) component control is slightly increased. When tapping, adjust the argon gas to the strong blowing mode: the argon gas pressure is maintained at 0.4-0.6MPa, and the flow rate is 150--250NL / min.

[0022] In the deoxidation alloying process, the deoxidation sequence is adjusted from the original strong deoxidation-weak deoxidation-strong deoxidation to weak deoxidation-strong deoxidation-strong deoxidation; the types and addition amounts of deoxidation alloying are as follows: silicon manganese (1 / 2 of the total amount is added first), aluminum block (0.5-1kg / t), silicon aluminum calcium (0.6-2kg / t). Strong deoxidation refers to the strong ability to react with oxygen, and weak deoxidation refers to the weak ability to react with oxygen. In the steel industry, it is generally believed that aluminum is a strong deoxidation element and manganese is a weak deoxidation element.

[0023] For the normal steel-tapping process, fine-tuning is not required. For the furnaces with slag-dropping, fine-tuning is required. For the furnaces with slag-dropping, 20-30kg of silicon carbide (about 0.16-0.25kg / t) or 30-40kg of calcium carbide (about 0.25-0.33kg / t) are added at the end of steel-tapping to diffuse and deoxidize the slag to ensure the physical and chemical properties of the slag. At this time, strong blowing is carried out, and the argon pressure is maintained at 0.4-0.6MPa, and the flow rate is 150--250NL / min. After 3-4 minutes of strong blowing, soft blowing is switched to; the flow rate and pressure of soft blowing are 0.4MPA, 50-100NL / min; the soft blowing time is greater than 10-12 minutes to promote the floating of inclusions. Before adding silicon carbide or calcium carbide, it is necessary to ensure that the ladle is well ventilated.

[0024] After the component concentration distribution and temperature distribution are adjusted to meet the requirements, the molten steel is transported to the continuous casting section for casting, and the original Q195L operating points are implemented.

[0025] The process method for smelting wire drawing steel Q195L in a converter provided by the present invention weakens the fine adjustment of the argon station and moves the fine adjustment link forward to the steel tapping and deoxidation alloying process at the end of blowing, so that the inclusions in the steel are significantly reduced, while still meeting the component requirements of the original production process for the wire drawing steel Q195L, the center crack is reduced, the elongation is increased, the wire breakage rate is reduced, and good wire drawing properties are embodied.

[0026] Product Comparison

[0027] Table 1 Low-power detection results of converter-smelted wire drawing steel Q195L obtained by prior art

[0028]

[0029] Table 2 Low-power detection results of converter-smelted wire drawing steel Q195L obtained in the embodiment of the present invention

[0030]

[0031] By comparing Table 1 and Table 2, it can be seen that, compared with the prior art process, the process of the embodiment of the present invention has an improvement in the central crack, and the content of non-metallic inclusions has also decreased.

[0032] Table 3 Grain size, hardness, tensile strength and elongation of converter-smelted wire drawing steel Q195L obtained by prior art

[0033]

[0034] Table 4 Grain size, hardness, tensile strength and elongation of converter-smelted wire drawing steel Q195L obtained in the embodiment of the present invention

[0035]

[0036] By comparing Table 3 and Table 4, it can be seen that compared with the prior art process, the elongation of the converter-smelted wire drawing steel obtained by the process of the embodiment of the present invention is increased, and the hardness is significantly reduced, which reflects better wire drawing process properties.

[0037] Table 5 Usage of converter smelted wire drawing steel Q195L obtained by prior art

[0038]

[0039] Table 6 Usage of converter-smelted wire drawing steel Q195L obtained by the process of the embodiment of the present invention

[0040]

[0041] By comparing Table 5 and Table 6, it can be seen that compared with the prior art, the wire breakage rate of the converter-smelted drawn steel obtained by the process of the embodiment of the present invention is significantly reduced regardless of whether it is 2.0 mm wire rod or 0.73 mm wire rod.

[0042] Table 7 Comparison of endpoint components between the process of the present invention and the process of the prior art

[0043]

[0044] Table 8 Comparison of deoxidation alloying parameters between the process of the embodiment of the present invention and the process of the prior art

[0045]

[0046] Comparing Table 7 and Table 8, we can see that Compared with the prior art, the process of the embodiment of the present invention has no significant changes in alloy recovery rate and element composition; Compared with the existing technology, the consumption of deoxidizer for aluminum blocks is reduced by about 0.14kg / t, which reduces the amount of brittle inclusions in steel and improves the purity of steel. In the deoxidation alloying process, compared with the prior art process, the alloy cost of the process of the embodiment of the present invention is reduced by about 2.38 yuan / t; In terms of the temperature drop of steel tapping, the temperature drop loss of the process of the embodiment of the present invention is 36.4°C, and the temperature drop loss in the prior art process is 27.5°C. The process of the embodiment of the present invention increases the temperature drop of steel tapping by 8.9°C. According to the carbon deoxidation temperature drop comparison, the carbon deoxidation participation in the steel tapping process is about 0.01%, affecting the temperature drop loss by 10°C, which meets the purpose of reducing non-metallic inclusions in steel.

[0047] The process method for smelting wire drawing steel Q195L in a converter provided by the present invention weakens the fine adjustment of the argon station and moves the fine adjustment link forward to the steel tapping and deoxidation alloying process at the end of blowing, so that the inclusions in the steel are significantly reduced, while still meeting the component requirements of the original production process for the wire drawing steel Q195L, the center crack is reduced, the elongation is increased, the wire breakage rate is reduced, and good wire drawing properties are embodied.

[0048] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" orientations or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0049] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention are all within the scope of patent protection of the present invention.

Claims

1. A process for smelting wire drawing steel in a converter, comprising: Step 1: adding molten iron and scrap steel into a converter, wherein the ratio of molten iron to scrap steel is adjusted according to the requirement of the tapping temperature; Step 2: Blowing high-pressure oxygen into the molten iron and the scrap steel to cause an oxidation-reduction reaction of the molten iron and the scrap steel; Characterized in that the process for smelting wire drawing steel in a converter also includes: Step 3: tapping at the end of blowing, adjusting the argon supply to a strong blowing mode during tapping, and performing a deoxidation and alloying process during tapping; and Step 4: After the component concentration distribution and temperature distribution are adjusted to meet the requirements, the molten steel is transported to the continuous casting section for casting.

2. The process for smelting wire drawing steel in a converter according to claim 1, characterized in that: In step 3, the strong blowing mode is to maintain the pressure at 0.4-0.6 MPa and the flow rate at 150-250 NL / min.

3. The process for smelting wire drawing steel in a converter according to claim 1, characterized in that: During the deoxidation alloying process, the types and order of added materials are silicon manganese, aluminum blocks, and silicon aluminum calcium.

4. The process for smelting wire drawing steel in a converter according to claim 1, characterized in that: For the heats with slag during steel tapping, silicon carbide or calcium carbide is added at the end of steel tapping to diffuse and deoxidize the slag to ensure the physical and chemical properties of the slag.

5. The process for smelting wire drawing steel in a converter according to claim 4, characterized in that: For the furnace with slag removal, the argon pressure is maintained at 0.4-0.6MPa at the end of tapping, and the flow rate is 150-250NL / min, and strong blowing is achieved for 3-4 minutes or switched to soft blowing.

6. The process for smelting wire drawing steel in a converter according to claim 5, characterized in that: The flow rate and pressure of soft blowing are 0.4MPa, 50-100NL / min.

7. The process for smelting wire drawing steel in a converter according to claim 6, characterized in that: Soft blowing time is greater than 10-12 minutes.

8. The process for smelting wire drawing steel in a converter according to claim 4, characterized in that: Before adding silicon carbide or calcium carbide, ensure that the ladle is well ventilated.

9. The process for smelting wire drawing steel in a converter according to claim 1, characterized in that: The final carbon (C) content at the end of blowing is ≤0.06% when the steel is tapped.

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