WO2021136066A1

WO2021136066A1 - Submerged arc welding wire steel for low alloy steel plate and preparation method therefor

Info

Publication number: WO2021136066A1
Application number: PCT/CN2020/139081
Authority: WO
Inventors: 徐灯亮; 梁鹏; 刘春森; 翟进坡
Original assignee: 唐山市德龙钢铁有限公司
Priority date: 2019-12-30
Filing date: 2020-12-24
Publication date: 2021-07-08
Also published as: CN111020355B; CN111020355A

Abstract

A submerged arc welding wire steel for a low alloy steel plate and a preparation method therefor. The weight percentages of the chemical compositions of the welding wire steel are: C=0.060-0.090%, Si=0.030-0.050%, Mn=0.95-1.05%, P≤0.015%, S≤0.010%, Cr≤0.10%, Ni≤0.05%, and Cu≤0.05%, with the balance being Fe and impurities. The preparation method comprises the steps of: desulfurization of molten iron using a KR, smelting in a converter, deoxidation and alloying, refining, and continuous casting. The welding wire product made of the submerged arc welding wire steel for a low alloy steel plate can improve the stability of the mechanical properties of welding seams, improve the low-temperature impact absorption as well as the welding bead forming effect and slag removal ability, thereby achieving the purpose of improving the welding effect. The preparation method is simple to operate and is suitable for industrial production.

Description

Submerged arc welding wire steel for low alloy steel plate and preparation method thereof

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on December 30, 2019, the application number is CN201911396852.6, and the invention title is "a submerged arc welding wire steel for low-alloy steel plate and its preparation method". The entire content is incorporated into this application by reference.

Technical field

The invention belongs to the technical field of welding steel, and specifically relates to a submerged arc welding wire steel for low alloy steel plates and a preparation method thereof.

Background technique

With the improvement of automatic welding technology, submerged arc welding is widely used in welding large workpieces due to its advantages of high welding production efficiency and low welding labor intensity. With different fluxes, it can meet the welding requirements of different workpieces and has a wide range of applications. SU26 submerged arc welding wire is not sensitive to the rust on the base metal. It can be welded by single, bipolar, AC or DC. It can be used with HJ350 and other fluxes to achieve high-speed welding and filling welding of 50kg base metal. Submerged arc welding wire is affected by the quality of the base metal wire rod, resulting in large fluctuations in the mechanical properties of the weld, low low-temperature impact absorption, poor weld bead forming and slag removal, and the welding quality is not ideal.

Summary of the invention

In view of this, the purpose of the present invention is to provide a submerged arc welding wire steel for low-alloy steel plates and a preparation method thereof, which aims to enhance the stability of the mechanical properties of the weld, improve the low-temperature impact absorption energy, and the weld bead forming effect and slag removal. To achieve the purpose of improving the use effect of welding users.

In order to achieve the objectives of the above invention, the present invention provides the following technical solutions:

The present invention provides a method for preparing submerged arc welding wire steel for low alloy steel plates, which is characterized in that it comprises the following steps:

Mixing molten iron and desulfurizing agent for KR desulfurization, so that the sulfur content in the molten iron is ≤0.010wt% and the phosphorus content is ≤0.125wt% to obtain desulfurized molten iron, and the desulfurizing agent includes lime and fluorite;

The desulfurized molten iron and steel scrap are charged into a converter for converter smelting. The converter smelting slagging material is added during the smelting process to obtain the final molten steel of the converter smelting. The converter smelting slagging material includes lime and magnesium balls. The mass ratio is 7-9:1-3, and P≤0.013wt%, S≤0.010wt%, and C0.05～0.07wt% in the molten steel at the end point of the converter smelting;

Adding aluminum ferromanganese and low-carbon ferromanganese during the tapping process of the molten steel at the end of the converter smelting process for deoxidizing and alloying to obtain crude molten steel;

The crude molten steel is mixed with heating slag and then refined to obtain refined molten steel. The refining includes the following steps: adding lime and fluorite to the surface of the crude molten steel slag after preparing the heating slag for slagging, and adding silicon Iron powder and silicon carbide are slag adjusted, the chemical composition, free oxygen content, and temperature of the molten steel meet the control range, and the ladle car is driven out of the refining position for soft blowing;

The refined molten steel is continuously cast to obtain the submerged arc welding wire steel for low alloy steel plate. The weight percentage of the chemical composition of the submerged arc welding wire steel for low alloy steel plate is: C: 0.060-0.090%, Si: 0.030～0.050%, Mn: 0.95～1.05%, P≤0.015%, S≤0.010%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%, the balance is Fe and impurities.

Preferably, the mass ratio of lime to fluorite in the desulfurizing agent is 9:1.

Preferably, the amount of lime in the desulfurizer is 13-15 kg/t molten iron, and the amount of fluorite in the desulfurizer is 1.5 kg/t molten iron.

Preferably, the amount of lime in the converter smelting slagging material is 50-60 kg/t of total charging, and the amount of magnesium ball in the converter smelting slagging material is 8-13 kg/t of total charging.

Preferably, the converter smelting slagging material is added in two batches, and 2/3 of the converter smelting slagging material is added 5 minutes before blowing, and the remaining converter smelting slagging material is added within 10 minutes of blowing.

Preferably, the basicity of the final slag smelted by the converter is 3-4.

Preferably, the temperature of the tapping is 1590-1610°C.

Preferably, the oxygen content of the molten steel at the end of the converter smelting is 30-40 ppm.

Preferably, the amount of the hot slag is 3kg/t of crude molten steel.

Preferably, in the refining, the amount of lime is 3 to 5 kg/t of crude molten steel obtained with heating slag, and the amount of fluorite is 1 to 2 kg/t of crude molten steel obtained with heating slag, silicon The amount of iron powder is 80-100kg/t of refined slag, and the amount of silicon carbide is 80-100kg/t of refined slag.

Preferably, the alkalinity of the refining slag is 2.5-3.5.

Preferably, the sum of the mass percentages of FeO and MnO in the refining slag is 1.5-2.5%.

Preferably, the oxygen content of the refined molten steel is 20-30 ppm.

The present invention also provides the submerged arc welding wire steel for low alloy steel plate prepared by the preparation method described in the above technical solution, and the weight percentage of the chemical composition of the submerged arc welding wire steel for low alloy steel plate is: C: 0.060-0.090%, Si: 0.030～0.050%, Mn: 0.95～1.05%, P≤0.015%, S≤0.010%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%, the balance is Fe and impurities.

The invention provides a method for preparing submerged arc welding wire steel for low alloy steel plates, which includes the following steps: mixing molten iron and a desulfurizing agent for KR desulfurization, so that the sulfur content in the molten iron is ≤0.010wt% and the phosphorus content is ≤0.125wt%, To obtain desulfurized molten iron, the desulfurizing agent includes lime and fluorite; the desulfurized molten iron and scrap steel are charged into a converter for converter smelting, and the converter smelting slag material is added during the smelting process to obtain the final molten steel for converter smelting, and the converter smelting slag The materials include lime and magnesium balls, the mass ratio of the desulfurized molten iron to the scrap steel is 7-9:1-3, and the final molten steel in the converter smelting P≤0.013wt%, S≤0.010wt%, C: 0.05～0.07wt %; In the process of molten steel tapping at the end of the converter smelting process, aluminum ferromanganese and low-carbon ferromanganese are added for deoxidation and alloying to obtain crude molten steel; the crude molten steel is refined with heating slag to obtain a refined The refining of molten steel includes the following steps: adding lime and fluorite to the surface of the crude molten steel slag after heating the slag for slagging, adding ferrosilicon powder and silicon carbide to adjust the slag, the chemical composition and free oxygen content of the molten steel, After the temperature meets the control range, the ladle car is driven out of the refining position for soft blowing; the refined molten steel is continuously cast to obtain the submerged arc welding wire steel for the low-alloy steel plate, and the submerged arc welding wire steel for the low-alloy steel plate The weight percentage of chemical composition is: C: 0.060～0.090%, Si: 0.030～0.050%, Mn: 0.95～1.05%, P≤0.015%, S≤0.010%, Cr≤0.10%, Ni≤0.05%, Cu≤ 0.05%, the balance is Fe and impurities. The present invention controls the sulfur content below 0.010wt% through KR desulfurization and reduces the desulfurization pressure in the refining process; in the converter smelting process, the converter heat is balanced by controlling the ratio of molten iron to scrap, so that the converter end temperature is within a suitable range, while using The slagging material is mixed and added in batches for converter smelting, and the final phosphorus content of the converter is controlled in a lower range. By controlling the carbon content at the end of the converter, the molten steel at the end of the converter smelting can obtain a lower free oxygen content, reduce the large amount of deoxidizers, and reduce the content of slag silicon and manganese deoxidation products; during the tapping alloying process, aluminum manganese and ferromanganese are added. Low carbon manganese steel composite deoxidizer can improve the deoxidation effect of the deoxidation alloying process and reduce the deoxidation pressure of the refining process; the refining process adopts hot slag circulation to improve the submerged arc effect of the refining process, and the slag regulator (ferrosilicon powder) is added during the refining process. +Silicon Carbide) to produce white slag, and control the FeO%+MnO% content in the top slag within an appropriate range, stabilize the silicon and manganese return of the molten steel during the refining process, and realize the precise control of the alloying elements of low silicon and high manganese steel.

By adopting the casting billet produced by the method for producing submerged arc welding wire steel casting billet for low alloy steel plate provided by the present invention, the finished welding wire made by rolling and drawing can enhance the stability of the mechanical properties of the weld, improve the low-temperature impact absorption energy and the weld bead Forming effect and slag removal, to achieve the purpose of improving the welding effect.

The invention guides a new direction and new idea for the improvement of the welding wire steel wire rod manufacturing process. Moreover, the production method provided by the invention has simple operation and is suitable for industrialized production.

Detailed ways

The invention provides a preparation method of submerged arc welding wire steel for low alloy steel plates, which comprises the following steps:

1. Mixing molten iron and desulfurizing agent for KR desulfurization, so that the sulfur content in the molten iron is ≤0.010wt% and the phosphorus content is ≤0.125wt% to obtain desulfurized molten iron. The desulfurizing agent includes lime and fluorite;

2. Load the desulfurized molten iron and scrap steel into a converter for converter smelting. During the smelting process, the converter smelting slagging material is added to obtain the final molten steel for converter smelting. The converter smelting slagging material includes lime and magnesium balls, and the desulfurized molten iron is combined with The mass ratio of scrap steel is 7-9:1-3, and P≤0.013wt%, S≤0.010wt%, C: 0.05-0.07wt% in molten steel at the end point of the converter smelting;

3. Adding aluminum ferromanganese and low-carbon ferromanganese during the tapping process of the molten steel at the end of the converter smelting process for deoxidation and alloying to obtain crude molten steel;

4. The crude molten steel is mixed with heating slag and then refined to obtain refined molten steel. The refining includes the following steps: adding lime and fluorite to the surface of the crude molten steel slag after the heating slag is added to make slag; Add ferrosilicon powder and silicon carbide for slag conditioning. After the chemical composition, free oxygen content, and temperature of the molten steel meet the control range, the ladle car will be driven out of the refining position for soft blowing;

5. Continuously casting the refined molten steel to obtain the submerged arc welding wire steel for low alloy steel plate. The weight percentage of the chemical composition of the submerged arc welding wire steel for low alloy steel plate is: C: 0.060-0.090%, Si: 0.030～0.050%, Mn: 0.95～1.05%, P≤0.015%, S≤0.010%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%, the balance is Fe and impurities.

In the present invention, the content of S in the molten iron is preferably ≤0.040wt%; the content of P in the molten iron is preferably ≤0.125wt%, and other elements are not particularly limited, which meets the requirements of the residual element chemistry of the submerged arc welding wire billet for low-alloy steel plates. The ingredients are sufficient.

In the present invention, the mass ratio of lime to fluorite in the desulfurizer is preferably 9:1. In the present invention, the amount of lime in the desulfurizer is preferably 13-15 kg/t molten iron, and the amount of fluorite in the desulfurizer is preferably 1.5 kg/t molten iron.

In the present invention, the amount of lime in the converter smelting slagging material is preferably 50-60 kg/t total charging amount, more preferably 55kg/t total charging amount. The amount of magnesium balls in the converter smelting slagging material The amount used is preferably 8-13 kg/t total charging amount, more preferably 10 kg/t total charging amount.

In the present invention, the converter smelting slagging material is preferably added in two batches, preferably 2/3 of the converter smelting slagging material is added 5 minutes before blowing, and the remaining converter smelting slagging material is preferably added within 10 minutes of blowing. The basicity of the final slag is preferably 3 to 4, which can ensure that the smelting end point P is less than or equal to 0.013%.

In the present invention, the low-high-low operation mode is preferably adopted for the gun positions in the early, middle and late stages of the converter smelting process, and the argon blowing and stirring intensity at the bottom of the converter adopts an incremental automatic control mode.

In the present invention, P≤0.013wt%, S≤0.010wt%, C: 0.05-0.07wt% in molten steel at the end of converter smelting, and the tapping temperature is preferably 1590-1610°C, more preferably 1610°C. Control the carbon content and temperature at the end of the converter to make the molten steel at the end of converter smelting a lower free oxygen content, reduce the amount of deoxidizer added, and avoid the silicon and manganese return of the molten steel during the refining process.

The present invention does not specifically limit the amount of the aluminum-manganese-iron and low-carbon manganese steel, as long as the chemical composition of the submerged arc welding wire steel for the low-alloy steel plate can be guaranteed. In the present invention, the addition of a composite deoxidizer of aluminum-manganese-iron and low-carbon manganese steel can improve the deoxidation effect of the alloying process and reduce the generation of silicon and manganese deoxidation products.

In the present invention, the steel tapping process is preferably as follows: firstly, the molten steel is poured into the ladle, the aluminum ferromanganese and low-carbon ferromanganese are added into the ladle while the molten steel flows in, and the amount of air blown at the bottom of the ladle is controlled to make the alloy Melt as soon as possible. After observing the melting of the alloy, add lime to the ladle to make the ladle have a certain thickness of top slag. Use the slag stop cone to stop the slag for tapping and quickly lift the furnace. The slag stop cone can stably reduce the amount of slag.

In the present invention, it is preferable that the ladle car obtained from steel tapping is driven to the argon blowing station, and the oxygen content analyzer is used to measure the free oxygen content in the molten steel, and the aluminum wire is fed according to the measured value to control the oxygen content in the molten steel in the range of 30-40 ppm , To reduce the deoxygenation pressure in the refining process.

After obtaining the deoxidized alloyed molten steel, the present invention mixes the deoxidized alloyed molten steel with heating slag and then performs refining to obtain refined molten steel. The refining includes the following steps: mixing the obtained mixture with lime and fluorite for slagging, Then, ferrosilicon powder and silicon carbide are added for slag adjustment, and finally argon is soft blown.

In the present invention, the amount of the hot slag is preferably 3kg/t of crude molten steel, and the heating slag can effectively increase the slag formation rate. In the present invention, the hot slag is preferably the remaining hot slag of the ladle after casting of the last furnace of molten steel.

In the present invention, the refining is preferably performed in an LF refining furnace. In the present invention, the LF refining furnace is preferably connected to argon gas to break the shell, and then the graphite electrode is heated and melted by electricity. The alkalinity of the refining slag used in the refining is preferably 2.5 to 3.5, which can be heated at high power. Under the premise, it has a good foaming submerged arc effect and the ability to adsorb inclusions.

In the present invention, in the refining process, the amount of lime is preferably 3 to 5 kg/t of molten steel obtained after heating slag, and the amount of fluorite is preferably 1 to 2 kg/t of crude steel after heating slag. For the molten steel, the amount of ferrosilicon powder is 80-100kg/t of refined slag, and the amount of silicon carbide is 80-100kg/t of refined slag. In the present invention, 3 minutes after the start of refining, lime is added for slagging; the fluorite can promote slagging; the silicon carbide is a foaming agent, which can make the slag foaming uniformly and stably, and fully foaming Reduce the oxides in the slag; the ferrosilicon powder is a deoxidizer that diffuses and deoxidizes the slag slag surface, maintains the reduction performance of the slag, and controls the range of (FeO%+MnO) in the refining slag to be 1.5 to 2.5%, which is beneficial to control refining The amount of silicon and manganese returned to molten steel in the process.

In the present invention, the slag is preferably stirred with argon gas, LF refining adopts high-end, medium and short arc high-power mode, ladle bottom blowing strong stirring mode to quickly generate slag, and the ladle bottom blowing pressure is controlled at 0.5-0.8Mpa , It can quickly form a slag with uniform composition.

In the present invention, the deoxidizer is preferably added to the slag surface in 2 times;

In the present invention, the slag modifier is added after heating for 5 minutes in the refining process, and the slag modifier is added according to the refining slag obtained by silicon carbide 40kg/t + ferrosilicon powder 40kg/t. After heating for 10 minutes, the obtained blending agent is added. The molten steel after heating the slag is subjected to temperature measurement, sampling, and observation of the refining slag. If the temperature of the molten steel does not reach 1570°C or higher, it needs to be supplied with electricity to increase the temperature. The sampling operation is allowed only when the temperature reaches 1570°C or higher. The function is to ensure the alloy is fully melted at a suitable temperature and improve the accuracy of sampling composition detection. In the present invention, a special tool is preferably used to dip the slag, observe the color of the slag, and judge the subsequent deoxidizer addition amount according to the color of the slag. When the slag is blacked in the secondary refining, the slag modifier is added according to the refined slag obtained from 60kg/t of silicon carbide + 60kg/t of ferrosilicon powder; the slag color is yellowed and the deoxidizer is added according to the refined slag obtained from 40kg/t of silicon carbide + silicon Refining slag obtained from iron powder 40kg/t, heating the molten steel to the leaving station temperature and then driving the ladle car out of the refining position for soft blowing, controlling the creeping of the slag surface at the bottom of the ladle blowing pressure, and detecting the oxygen content of the molten steel before loading the steel, and controlling the oxygen content The target is 20-30 ppm, and the purpose is to control the reversion of silicon and manganese at the interface between the molten steel in the ladle and the steel slag during the casting process.

In the present invention, after the refining is out of the station, it is preferable to perform argon soft blowing on the molten steel. The inlet pressure of the argon gas is suitable for slag surface creeping, and the soft blowing time is preferably not less than 15 minutes.

After the refined molten steel is obtained, continuous casting is performed on the refined molten steel to obtain the submerged arc welding wire billet for low alloy steel plate. The weight percentage of the chemical composition of the submerged arc welding wire steel for low alloy steel plate is: C: 0.060～0.090%, Si: 0.030～0.050%, Mn: 0.95～1.05%, P≤0.015%, S≤0.010%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%, the balance is Fe and impurities .

Example 1

Process equipment configuration: 80tKR desulfurization, 80t top and bottom combined blowing converter, 80tLF refining furnace, 6-machine/6-strand continuous casting machine (R9m, 160mm*160mm).

(1) KR desulfurization: S content in molten iron is 0.033%, P content is 0.118%, add 13kg/t molten iron with white ash, 1.5kg/t molten iron with fluorite, stir for 10 minutes, take a sample and analyze the molten iron after slagging, the content of molten iron S is 0.005% .

(2) Converter smelting: The ratio of molten iron and steel scrap into converter desulfurization is 7:3, white ash 45kg/t molten steel and magnesium ball 5kg/t molten steel are added, slagging material is added in two batches, and slagging material is added 5 minutes before blowing 2/3, the rest of the slagging material is preferably added within 10 minutes of blowing. In the converter smelting process, the lance position is 1.2m in the early stage, 1.4m in the middle stage, 0.8m in the later stage, the converter bottom blowing stirring intensity is 250Nm/h in the early stage, 400Nm/h in the middle stage, and 500Nm/h in the later stage, the final slag basicity R: 3.0, and the converter smelting end point C is 0.050 %, S content is 0.006%, P content is 0.013%, temperature is 1610℃; during tapping, add ferromanganese and low-carbon ferromanganese according to the target composition in sequence. The amount of bottom blowing gas should be such that the alloy does not accumulate, and slag blocking is adopted. Cone stop slag taps steel and raise furnace quickly. The ladle car drove to the argon blowing station, and the oxygen content analyzer was used to determine the free oxygen content in the molten steel. According to the measured value, the aluminum wire was fed to adjust the oxygen, and the free oxygen content in the molten steel was 40ppm.

(3) LF refining:

A. Add about 250kg of hot slag into the ladle, add white ash for slagging 3 minutes after the start of refining, and add refined white ash 3kg/t molten steel and fluorite 1.25kg/t molten steel in the refining process 5 minutes after the start of refining. The power transmission gear adopts a mid-arc mode, and the bottom blowing pressure of the ladle is 0.6Mpa to heat up the slag. After heating for 5 minutes, add the slag modifier. The slag modifier is based on the slagging material obtained by silicon carbide 40kg/t + ferrosilicon powder 40kg/ t The resulting slagging material is added.

B. After heating for 10 minutes, the temperature of the molten steel is measured, the temperature of the molten steel is 1562°C, and the temperature of the molten steel reaches 1571°C after the power is transmitted and the temperature is increased for 2 minutes. Sampling and analyzing the composition of molten steel, adjust the chemical composition of C, Si, Mn to the steel grade control range, use a special tool to dip the slag to observe the color of the slag, the slag is black, the slag conditioning agent is based on the slagging material obtained from silicon carbide 60kg/t + ferrosilicon powder The 60kg/t slagging material is mixed and added, silicon carbide and ferrosilicon powder are successively added during the refining process for secondary slag adjustment, and the second-stop long-arc mode is used for power transmission and temperature rise. The bottom blowing pressure of the ladle is controlled at 0.5Mpa to maintain the refined slag In the reducing atmosphere operation, the molten steel was heated to 1595°C, and then the ladle car was driven out of the refining position for 16 minutes of soft ladle blowing, and the pressure at the bottom of the ladle was controlled to creep on the slag surface. The molten steel free oxygen was measured at 30 ppm on the steel. The refining slag is taken for analysis before steel loading, the basicity R of the refining slag is 2.5, and the (FeO%+MnO) in the refining slag is 1.5%.

(4) Continuous casting: use the conventional means of this process to control to obtain a 160mm*160mm billet.

Billet chemical composition: C: 0.06%, Si: 0.030%, Mn: 0.95%, P: 0.014%, S: 0.005%, Cr: 0.05%, Ni: 0.04%, Cu: 0.03%, the balance is Fe and Impurities.

Example 2

(1) KR desulfurization: S content in molten iron is 0.030%, P content is 0.130%, add white ash 14kg/t molten iron and fluorite 1.5kg/t molten iron, stir for 10 minutes, take a sample and analyze the molten iron after slagging, the molten iron S content is 0.008% .

(2) Converter smelting: The ratio of molten iron and steel scrap into converter desulphurization is 8:2, white ash 43kg/t molten steel and magnesium ball 5.6kg/t molten steel are added, slagging material is added in two batches, and slagging is added 5 minutes before blowing. 2/3 of the material, the remaining slagging material is preferably added within 10 minutes of blowing. In the converter smelting process, the gun position is 1.2m in the early stage, 1.4m in the middle stage, 0.8m in the later stage, the converter bottom blowing and stirring intensity is 250Nm/h in the early stage, 400Nm/h in the middle stage, and 500Nm/h in the later stage, the final slag basicity R: 3.5, and the converter smelting end point C is 0.060 %, S is 0.007%, P content is 0.012%, temperature is 1600°C; during tapping, add aluminum ferromanganese and low-carbon ferromanganese according to the target composition in sequence. The amount of bottom blowing air should be such that the alloy does not build up, and slag blocking is adopted. Cone stop slag taps steel and raise furnace quickly. The ladle car drove to the argon blowing station, and the oxygen content analyzer was used to determine the free oxygen content in the molten steel. According to the measured value, the aluminum wire was fed to adjust the oxygen. The free oxygen content in the molten steel was 34ppm.

(3) LF refining:

A. Add about 260kg of hot slag into the ladle, add white ash for slagging 3 minutes after the start of refining, and add refined white ash 3kg/t molten steel and fluorite 1.30kg/t molten steel during the refining process 5 minutes after the start of refining. The power transmission gear adopts a mid-arc mode with a ladle bottom blowing pressure of 0.6Mpa for slagging and heating. The slagging agent is added according to the slagging material obtained from 40kg/t of silicon carbide + 40kg/t of ferrosilicon powder.

B. After heating for 10 minutes, measure the temperature of the molten steel. The temperature of the molten steel is 1575℃. Sample and analyze the composition of the molten steel. Adjust the chemical composition of C, Si, Mn to the steel grade control range. Use a special tool to dip the slag to observe the slag color. The slag turns black. The slagging agent is added according to the slagging material obtained from 60kg/t of silicon carbide + 60kg/t of ferrosilicon powder. During the refining process, silicon carbide and ferrosilicon powder are successively added for secondary slag adjustment, and a second long arc is adopted. Mode power transmission and heating, the bottom blowing pressure of the ladle is controlled at 0.5Mpa, the refining slag is maintained at a reducing atmosphere, the molten steel is heated to 1595℃, and then the ladle car is driven out of the refining position for 16 minutes of soft blowing to control the bottom blowing pressure of the ladle and the slag surface creeping , Shanggang's oxygen is 25ppm. The refining slag was taken for analysis before steel loading, the basicity R of the refining slag was 2.6, and the (FeO%+MnO) in the refining slag was 2.5%.

Billet chemical composition: C: 0.075%, Si: 0.040%, Mn: 1.00%, P: 0.012%, S: 0.005%, Cr: 0.05%, Ni: 0.03%, Cu: 0.03%, the balance is Fe and Impurities.

Example 3

(1) KR desulfurization: S content in molten iron is 0.037%, P content is 0.130%, adding white ash 13kg/t molten iron, fluorite 1.57kg/t molten iron, stirring for 10 minutes, sampling and analysis after removing the slag from molten iron, the sulfur content of molten iron is 0.008% .

(2) Converter smelting: The ratio of molten iron and steel scrap into converter desulfurization is 9:1, white ash 44kg/t molten steel and magnesium ball 6kg/t molten steel are added, slagging material is added in two batches, and slagging material is added 5min before blowing. 2/3, the rest of the slagging material is preferably added within 10 minutes of blowing. The lance position of the converter smelting process is 1.2m in the early stage, 1.4m in the middle stage and 0.8m in the later stage, the converter bottom blowing stirring intensity is 250Nm/h in the early stage, 400Nm/h in the middle stage, and 500Nm/h in the latter stage, the final slag basicity R: 4.0, the final C content of converter smelting is 0.070 %, S content 0.007%, P content 0.013%, temperature 1590℃; during tapping, add aluminum ferromanganese and low-carbon ferromanganese according to the target composition in sequence. The amount of bottom blowing air should be such that the alloy does not build up, and slag blocking is adopted. Cone stop slag taps steel and raise furnace quickly. The ladle car drove to the argon blowing station, and the oxygen content analyzer was used to determine the free oxygen content in the molten steel. According to the measured value, the aluminum wire was fed to adjust the oxygen, and the free oxygen content in the molten steel was 40ppm.

(3) LF refining:

A. Add about 260kg of hot slag into the ladle, add white ash to make slag 3 minutes after the start of refining, and add 3.5 kg/t molten steel and 1.25 kg/t molten steel in the refining process 5 minutes after the start of refining. , The power transmission gear adopts a mid-arc mode, the bottom blowing pressure of the ladle is 0.6Mpa for slagging and heating, and the slagging agent is added according to the slagging material obtained from 40kg/t of silicon carbide + 40kg/t of ferrosilicon powder.

B. After heating for 10 minutes, measure the temperature of the molten steel, the temperature of the molten steel is 1575℃, sample and analyze the composition of the molten steel, adjust the chemical composition of C, Si, Mn to the steel grade control range, use a special tool to dip the slag to observe the color of the slag, the color of the slag turns yellow , The deoxidizer is added according to the slagging material obtained from 40kg/t of silicon carbide + 40kg/t of ferrosilicon powder. During the refining process, silicon carbide and ferrosilicon powder are successively added for secondary slag adjustment. Arc mode power transmission and heating, the bottom blowing pressure of the ladle is controlled at 0.5Mpa, and the refining slag is maintained at a reducing atmosphere. The molten steel is heated to 1595℃, and then the ladle car is driven out of the refining position for soft blowing for 17 minutes to control the bottom blowing pressure of the ladle and the slag surface Creeping, the upper steel determines the oxygen at 20ppm. The refining slag was taken for analysis before steel loading. The basicity R of the refining slag was 3.0, and the (FeO%+MnO) in the refining slag was 2.0%.

Billet chemical composition: C: 0.090%, Si: 0.050%, Mn: 1.05%, P: 0.014%, S: 0.006%, Cr: 0.05%, Ni: 0.03%, Cu: 0.02%, the balance is Fe and Impurities.

Test case

The H08Mn low-alloy steel plates prepared in Examples 1 to 3 were rolled into 6.5mm hot-rolled wire rods with submerged arc welding wire steel casting billets, which were mechanically dephosphorized, drawn, and copper-plated to produce finished welding wires with a diameter of 4.0mm before welding. Performance test (GB/T2650-2008 impact test method for welded joints; GB/T2651-2008 tensile test method for welded joints; GB/T2652-2008 weld and perfuser tensile test method; GB/T3323-2005 metal fusion welding welding (Joint radiography)

Table 1 Weld performance test results

It can be seen from Table 1 that the finished wire weld made of the submerged arc welding wire steel cast billet for low alloy steel plate provided by the present invention has high mechanical properties, high low-temperature impact absorption energy, good weld bead formation and slag removal, and welding effect it is good. The invention guides a new direction and new thinking for the improvement of the submerged arc welding wire steel production process, and the production method provided by the invention is simple in operation and suitable for industrialized production.

The description of the above embodiments is only used to help understand the method and the core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown in this document, but should conform to the widest scope consistent with the principles and novel features disclosed in this document.

Claims

A method for preparing submerged arc welding wire steel for low-alloy steel plates, which is characterized in that it comprises the following steps:

Mixing molten iron and desulfurizing agent for KR desulfurization, so that the sulfur content in the molten iron is ≤0.010wt% and the phosphorus content is ≤0.125wt% to obtain desulfurized molten iron, and the desulfurizing agent includes lime and fluorite;

The desulfurized molten iron and steel scrap are charged into a converter for converter smelting. The converter smelting slagging material is added during the smelting process to obtain the final molten steel of the converter smelting. The converter smelting slagging material includes lime and magnesium balls. The mass ratio is 7-9:1-3, and P≤0.013wt%, S≤0.010wt%, and C0.05～0.07wt% in the molten steel at the end point of the converter smelting;

Adding aluminum ferromanganese and low-carbon ferromanganese during the tapping process of the molten steel at the end of the converter smelting process for deoxidizing and alloying to obtain crude molten steel;

The crude molten steel is mixed with heating slag and then refined to obtain refined molten steel. The refining includes the following steps: adding lime and fluorite to the surface of the crude molten steel slag after preparing the heating slag for slagging, and adding silicon Iron powder and silicon carbide are slag adjusted, the chemical composition, free oxygen content, and temperature of the molten steel meet the control range, and the ladle car is driven out of the refining position for soft blowing;

The refined molten steel is continuously cast to obtain the submerged arc welding wire steel for low alloy steel plate. The weight percentage of the chemical composition of the submerged arc welding wire steel for low alloy steel plate is: C: 0.060-0.090%, Si: 0.030～0.050%, Mn: 0.95～1.05%, P≤0.015%, S≤0.010%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%, the balance is Fe and impurities.
The preparation method according to claim 1, wherein the mass ratio of lime to fluorite in the desulfurizing agent is 9:1.
The preparation method according to claim 1 or 2, wherein the amount of lime in the desulfurizer is 13-15 kg/t molten iron, and the amount of fluorite in the desulfurizer is 1.5 kg/t molten iron.
The preparation method according to claim 1, wherein the amount of lime in the converter smelting slagging material is 50-60 kg/t total charge, and the amount of magnesium balls in the converter smelting slagging material is 8 ~13kg/t total loading capacity.
The preparation method according to claim 1 or 4, characterized in that, the converter smelting slagging material is added in two batches, and 2/3 of the converter smelting slagging material is added 5 minutes before blowing, and the remaining converter smelting slagging material is in Add it within 10 minutes of blowing.
The preparation method according to claim 1, wherein the basicity of the final slag smelted in the converter is 3-4.
The preparation method according to claim 1, wherein the tapping temperature is 1590-1610°C.
The preparation method according to claim 1, wherein the oxygen content of the molten steel at the end of the converter smelting is 30-40 ppm.
The preparation method according to claim 1, wherein the amount of the hot slag is 3 kg/t of crude molten steel.
The preparation method according to claim 1, characterized in that, in the refining, the amount of lime is 3~5kg/t to obtain the crude molten steel after heating slag, and the amount of fluorite is 1 to 2kg/t. After preparing the crude molten steel after heating the slag, the amount of ferrosilicon powder is 80-100kg/t of refined slag, and the amount of silicon carbide is 80-100kg/t of refined slag.
The preparation method according to claim 10, wherein the alkalinity of the refining slag is 2.5-3.5.
The preparation method according to claim 10 or 11, wherein the sum of the mass percentages of FeO and MnO in the refining slag is 1.5-2.5%.
The preparation method according to claim 1, wherein the oxygen content of the refined molten steel is 20-30 ppm.
The submerged arc welding wire steel for low alloy steel plate prepared by the preparation method of any one of claims 1-13, wherein the weight percentage of the chemical composition of the submerged arc welding wire steel for low alloy steel plate is: C: 0.060 ～0.090%, Si: 0.030～0.050%, Mn: 0.95～1.05%, P≤0.015%, S≤0.010%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%, the balance is Fe and impurities.