Production method of 30MnSi wire rod with specification of 12mm

Abstract

The invention relates to the technical field of ferrous metallurgy, and particularly discloses a 12mm-specification 30MnSi wire rod production method which comprises the following steps: 1) uniformly heating a continuous casting square billet through a three-section walking beam furnace; (2) after being discharged from the furnace, the steel billet is rolled by rough rolling, intermediate rolling and pre-finishing rolling units of a rolling line; (3) the rolled piece is cooled again after passing through a finishing mill unit, a Dalnell high-speed flying shear device is installed in front of a wire feeding machine, and the wire feeding machine produces finished coiled snail products; (4) after spinning, slow cooling and heat preservation are conducted through a Stelmor air cooling line, and the internal structure of the finished steel is adjusted to be ferrite and pearlite; the plasticity and the strength of the finished steel are enhanced by controlling the heating temperature, the rolling starting temperature, the deformation amount and segmented cooling, meanwhile, alloy elements are adjusted, consumption of precious metal resources is reduced, the production cost is reduced, the product performance is improved, and the product performance index is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of iron and steel metallurgy, and particularly relates to a production method for 30MnSi wire rods with a specification of 12 mm. Background Art

[0002] The 30MnSi industrial wire rod of high-speed wire is a steel type produced according to the national standard GB / T24587-2009. It is a steel type of low and medium carbon high-quality carbon structural steel and alloy steel wire rod, with excellent tensile properties and surface quality, and is mainly used for prestressed concrete steel bars, having a wide application prospect.

[0003] Adding a large amount of trace elements leads to an increase in production cost and an increase in the consumption of precious metal resources. At the same time, due to the use of high starting rolling temperature and high spinning temperature, quality defects such as skinning, bulging, and bubbles are likely to appear on the product surface; using 6000 mm short square billets for rolling results in low production efficiency and an increase in energy consumption during the rolling process. However, in actual production, defects such as coarse grains, pores, and inclusions may occur, and these defects will reduce the strength and toughness of the wire rod. Therefore, a production method for 30MnSi steel type of high-speed wire rod with a specification of 12 mm is designed to solve the problems of high production cost and quality defects existing in the existing 30MnSi steel type of high-speed wire rod. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a production method for 30MnSi wire rods with a specification of 12 mm, which enhances the plasticity and strength of the finished steel by controlling the heating temperature, starting rolling temperature, deformation amount, and sectional cooling, and at the same time adjusts the alloying elements to reduce the production cost.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a production method for 30MnSi wire rods with a specification of 12 mm, including the following steps:

[0006] 1) Using continuous casting square billets to be uniformly heated through a three-stage walking beam heating furnace;

[0007] 2) After the steel billets are taken out of the furnace, they are rolled through the rough rolling, medium rolling, and pre-finishing rolling mills of the rolling line;

[0008] 3) After passing through the finishing rolling mill, the rolled piece is cooled again, and a Danieli high-speed flying shear device is installed in front of the spinning machine to produce spiral bar finished products by the spinning machine;

[0009] 4) After spinning, it passes through the Stelmor air-cooling line for slow cooling and heat preservation to adjust the structure inside the finished steel to ferrite + pearlite.

[0010] Specifically, the chemical composition of the continuous casting billet used in step 1) has the following weight percentages: C: 0.29 - 0.32; Si: 0.85 - 1.05, Mn: 1.0 - 1.2, impurity elements of S and P ≤ 0.02, no need for niobium and vanadium precious metal elements, and nitrogen content ≤ 70 ppm.

[0011] Specifically, the size of the continuous casting billet in step 1) is 165 * 165 * 12000 mm.

[0012] Specifically, the three - stage walking beam reheating furnace in step 1) adopts intelligent combustion control technology, and different temperature range standards are set according to different steel grades and production specifications.

[0013] Specifically, when evenly heating and producing 30MnSi steel grade with a 12 - mm specification from cold billets in step 1), the temperature of the second heating section is controlled at 960 °C, the first heating section is controlled at 1070 °C, the soaking section is controlled at 1100 °C. When using cold billets for production, the temperatures of each section increase to varying degrees. The rolling start temperature is controlled at 980 °C. Using automatic combustion technology, the through - bar temperature difference of the steel billet is controlled within 10 °C.

[0014] Specifically, in step 2), in the rough rolling area, medium rolling area, and pre - finishing rolling area of the rolling line, 14 horizontal - vertical alternating rolling mills and two Danieli finishing rolling mills are used to control the stock shape into a 19.5 - mm - diameter circle, and the cross - sectional area is controlled within 317 - 318 mm 2 ; Subsequently, it is cooled through two water tanks. The water supply pressure of the water tanks is controlled above 14 Bar for water piercing to control the cooling rate of the rolled piece. After shearing the head by the No. 3 flying shear, it enters the Danieli finishing rolling mill unit. At this time, the temperature is controlled at 935 ± 10 °C. The finishing rolling mill unit uses a one - drag - two 45° top - cross finishing rolling mill. Through the roll ring pass that is universal for all specifications, different numbers of rolling mills are used according to different production specifications, and the ovality at the outlet is controlled within 0.3 mm.

[0015] Specifically, in step 3), after passing through the finishing rolling mill unit, the rolled piece is cooled again. After passing through three water tanks, the temperature of the rolled piece is controlled at 945 °C and it enters the double - module unit. After passing through two rolling mills, the required product size is finally achieved. After finishing, it is evenly cooled in three water tanks in sections, and finally the laying - head temperature is also controlled at 880 ± 10 °C to ensure the surface of the product is dense, uniform, and smooth.

[0016] Specifically, a Danieli high - speed flying shear device is installed in front of the laying - head machine in step 3) to automatically shear the steel with oversized head and tail dimensions and unqualified mechanical properties. After laying - head, it passes through the Stelmor air - cooling line. In the air - cooling line, a heat - preservation cover is used to slowly cool the finished product, adjust the product structure, and ensure that the final finished product contains pearlite and ferrite inside and has no hardened layer.

[0017] The present invention has the following beneficial effects:

[0018] The 12mm 30MnSi round disc production method designed by the present invention controls the heating temperature, the rolling temperature, the deformation amount, and the segmented cooling to enhance the plasticity and strength of the finished steel, and adjusts the alloy elements at the same time, thereby reducing the consumption of precious metal resources and lowering the production cost.

[0019] The invention discloses a method for producing 12 mm 30MnSi round discs. The three-stage walking beam heating furnace adopts pulse combustion technology for automatic combustion to ensure uniform temperature of the steel rods. The walking beam speed is increased and a spaced-in furnace process is designed to reduce the furnace time of the steel billet, control grain growth and improve product performance.

[0020] The 12mm 30MnSi disc production method designed by the present invention controls a large reduction in a low-speed zone, so that the grains are severely deformed to improve the final performance of the product; the water tank is modified to increase the nozzle reaction speed, control the cooling rate of the rolled piece, and control the temperature of the rolled piece through process cooling and post-rolling cooling to ensure product performance indicators. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described in detail below. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] A method for producing 12 mm 30MnSi discs comprises the following steps:

[0023] 1. The continuous casting square billet with a size of 165*165*12000mm is uniformly heated through a three-stage walking beam heating furnace; the chemical composition weight percentage of the steel billet used for the continuous casting square billet is C: 0.29-0.32; Si: 0.85-1.05, Mn: 1.0-1.2, the impurity elements of S and P are ≤0.02, no niobium and vanadium precious metal elements are required, and the nitrogen content is ≤70ppm.

[0024] 2. After the billet is taken out of the furnace, it is rolled through the rough rolling, intermediate rolling and pre-finishing rolling units of the rolling line; after passing through the finishing rolling unit, the rolled piece is cooled again, and a Danieli high-speed flying shear is installed in front of the wire laying machine, and the wire laying machine produces finished coils; and water-penetrating cooling is set before and after the finishing rolling and after the module to adjust the cooling rate of the steel, control the grain deformation and phase change temperature, so as to improve the strength and plasticity of the steel. After wire laying, it passes through the Stelmor air cooling line for slow cooling and heat preservation, and adjusts the internal structure of the finished steel to ferrite + pearlite.

[0025] 3. The three-stage walking-beam heating furnace adopts intelligent combustion control technology and sets different temperature range standards according to the production steel type and production specifications.

[0026] 4. Uniform heating: When producing 30MnSi steel of 12mm specification with cold billets, the temperature of the second heating section is controlled at 960°C, the temperature of the first heating section is controlled at 1070°C, and the soaking section temperature is controlled at 1100°C. When using cold billets for production, the temperatures of each section increase to varying degrees. The rolling start temperature is controlled at 980°C. With the use of automatic combustion technology, the temperature difference along the length of the steel billet is controlled within 10°C.

[0027] 5. In the rough rolling area, medium rolling area, and pre-finishing rolling area of the rolling line, 14 horizontal-vertical alternating rolling mills and two Danieli finishing mills are used. The stock shape is controlled into a circle with a diameter of 19.5mm, and the cross-sectional area is controlled within 317 - 318mm 2 ; Subsequently, it is cooled through two water tanks. The water supply pressure of the water tanks is controlled above 14Bar for water penetration, controlling the cooling rate of the rolled piece. After shearing the head by the No. 3 flying shear, it enters the Danieli finishing mill unit. At this time, the temperature is controlled at 935 ± 10°C. The finishing mill unit uses a one-drag-two 45° top-cross finishing mill. Through the roll ring pass that is universal for all specifications, different stands of rolling mills are used according to different production specifications, and the ovality at the exit is controlled within 0.3mm.

[0028] 6. After passing through the finishing mill unit, the rolled piece is cooled again. After passing through three water tanks, the temperature of the rolled piece is controlled at 945°C and enters the double-module unit. After passing through two rolling mills, the required product dimensions are finally achieved. After the finished product, it is evenly cooled in three sections through water tanks, and finally the laying head temperature is also controlled at 880 ± 10°C, ensuring that the surface of the product is dense, uniform, and smooth.

[0029] 7. A Danieli high-speed flying shear device is installed in front of the laying head machine to automatically shear the steel with oversized head and tail dimensions and unqualified mechanical properties. After laying the head, it passes through the Stelmor air-cooling line. In the air-cooling line, a heat preservation cover is used to slow-cool the finished product, adjusting the product structure to ensure that the final finished product contains pearlite and ferrite and has no hardened layer.

[0030] The present invention has the following technical effects in actual operation.

[0031] 1. The controlled rolling and controlled cooling method of the present invention significantly reduces the alloy composition compared with the hot rolling production mode, improves the hourly output. Compared with hot rolling production, the comprehensive cost can be reduced by 72 yuan per ton, greatly reducing the production cost.

[0032] 2. By controlling the heating temperature, rolling start temperature, deformation amount, and sectional cooling, the plasticity and strength of the finished steel are enhanced. At the same time, the alloying elements can be adjusted, reducing the consumption of precious metal resources and lowering the production cost.

[0033] 3. The three-stage walking beam heating furnace adopts pulse combustion technology for automatic combustion to ensure uniform temperature of the steel rod. At the same time, it increases the speed of the walking beam and designs a space-to-furnace process to reduce the time the billet spends in the furnace, control grain growth, and improve product performance.

[0034] 4. Control the large amount of reduction in the low-speed zone to cause severe deformation of the grains to improve the final performance of the product; modify the water tank to increase the nozzle response speed, control the cooling rate of the rolled piece, control the temperature of the rolled piece through process cooling and post-rolling cooling, and ensure product performance indicators.

[0035] 5. The grain size of the product can reach level 10, the total decarburization layer (full decarburization + partial decarburization) is ≤1.5%D, the structure is ferrite + pearlite, and the dimensional accuracy can reach level C.

[0036] On-site specific implementation cases using the technical solution of the present invention:

[0037] On-site implementation case 1: On April 20, 2025, a company's high-speed wire production line organized the production of 12mm specification 30MnSi steel, produced 15 furnaces in total, and produced 2127.519 tons. Using this production process, the organization is uniform ferrite and pearlite, the grain size reaches level 10, the average tensile strength is 680Mpa, the average cross-sectional shrinkage rate is 50.4%, and the performance indicators are better than the national standard. The out-of-roundness of the finished product is controlled within 0.3mm, the depth of the decarburization layer is ≤1.5%D, and the surface quality of the product is good, without scratches, peeling and other problems.

[0038] On-site implementation case 2: On April 23, 2025, a company's high-speed wire production line organized the production of 12 specifications of 30MnSi steel, produced 11 furnaces in total, and produced 1,670.614 tons of steel. Using this production process, the organization is uniform ferrite and pearlite, the grain size reaches level 10, the average tensile strength is 679Mpa, the average cross-sectional shrinkage rate is 50.2%, and the performance indicators are better than the national standard. The out-of-roundness of the finished product is controlled within 0.3mm, the depth of the decarburization layer is ≤1.5%D, and the surface quality of the product is good, without scratches, peeling and other problems.

[0039] The present invention is not limited to the above-mentioned implementation modes, and anyone should be aware of the structural changes made under the enlightenment of the present invention, and all those having the same or similar technical solutions as the present invention fall within the protection scope of the present invention.

[0040] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A production method for 30MnSi coiled rod with a specification of 12 mm, characterized in that, It includes the following steps: 1) Using continuous casting billets to be uniformly heated in a three-stage walking beam reheating furnace; 2) After the billets are discharged from the furnace, they are rolled through the roughing, intermediate rolling, and pre-finishing mills of the rolling line; 3) After passing through the finishing mill, the rolled piece is cooled again. A Danieli high-speed flying shear is installed in front of the laying head, and the laying head produces coiled bar finished products; 4) After laying, it passes through the Stelmor air-cooling line for slow cooling and heat preservation to adjust the structure inside the finished steel to ferrite + pearlite.

2. The production method of 30MnSi coil with a specification of 12mm according to claim 1, characterized in that, The chemical composition weight percentages of the billets used for the continuous casting billets in step 1) are as follows: C: 0.29 - 0.32; Si: 0.85 - 1.05, Mn: 1.0 - 1.2, impurity elements of S and P ≤ 0.02, no need for niobium and vanadium precious metal elements, and nitrogen content ≤ 70 ppm.

3. The production method of 30MnSi coil with a specification of 12mm according to claim 1, characterized in that, The size of the continuous casting billets in step 1) is 165*165*12000 mm.

4. The production method of 12mm specification 30MnSi coiled bar according to claim 1, characterized in that, The three-stage walking beam reheating furnace in step 1) adopts intelligent combustion control technology, and different temperature range standards are set according to different steel grades and production specifications.

5. The production method of 30MnSi wire rod with a specification of 12mm according to claim 1, characterized in that, When uniformly heating in step 1) and producing 30MnSi steel grade with a 12 mm specification using cold billets, the temperature of the second heating section is controlled at 960 °C, the first heating temperature is controlled at 1070 °C, the soaking section temperature is controlled at 1100 °C. When using cold billets for production, the temperatures of each section increase to varying degrees, and the rolling start temperature is controlled at 980 °C. With the automatic combustion technology, the through-strip temperature difference of the billets is controlled within 10 °C.

6. The production method of 30MnSi coil with a specification of 12mm according to claim 1, characterized in that, In the rough rolling area, medium rolling area and pre-finishing rolling area of the rolling line in step 2), 14 horizontal-vertical alternating rolling mills and two Danieli finishing rolling mills are used to control the stock shape into a circle with a diameter of 19.5 mm, and the cross-sectional area is controlled within 317 - 318 mm 2 ; Subsequently, it is cooled through two water tanks. The water supply pressure of the water tanks is controlled above 14 Bar for water piercing to control the cooling rate of the rolled piece. After being sheared by the No. 3 flying shear, it enters the Danieli finishing rolling mill unit. At this time, the temperature is controlled at 935 ± 10 °C. The finishing rolling mill unit uses a one-drive-two 45° top-cross finishing rolling mill. Through the roll ring pass that is universal for all specifications, different numbers of rolling mills are used according to different production specifications, and the ovality at the outlet is controlled within 0.3 mm.

7. The production method of 12mm specification 30MnSi wire rod according to claim 6, characterized in that, In step 3), after passing through the finishing mill, the rolled piece is cooled again. After passing through three water tanks, the temperature of the rolled piece is controlled to 945 °C and enters the double-module unit. After passing through two rolling mills, the required product size is finally achieved. After finishing, it is cooled evenly in three water tanks in sections, and finally the laying temperature is also controlled at 880 ± 10 °C to ensure the surface of the product is dense, uniform, and smooth.

8. The production method of 12mm specification 30MnSi wire rod according to claim 6, characterized in that, In step 3), a Danieli high-speed flying shear is installed in front of the laying head to automatically shear the steel with oversized head and tail dimensions and unqualified mechanical properties. After laying, it passes through the Stelmor air-cooling line, and a heat preservation cover is used on the air-cooling line to slow-cool the finished product and adjust the product structure to ensure that the final finished product contains pearlite and ferrite and has no hardened layer.