A high-strength and high-toughness steel wire rod containing Cu and a production method thereof

Abstract

The present application relates to the technical field of metallurgy, and particularly relates to a high-strength and high-toughness welding steel wire rod containing Cu and a production method thereof, the steel wire rod comprises the following components by weight percentage: C 0.09-0.12%, Si 0.90-1.00%, Mn 1.65-1.75%, P≤0.010%, S≤0.010%, Cr≤0.10%, Ni 0.80-1.10%, Cu 0.40-0.60%, Mo≤0.05%, Ti≤0.01%, V 0.03-0.08%, B 0.003-0.006%, lanthanum element 0.05-0.08%, neodymium element 0.05-0.09%, and the rest is Fe and inevitable impurities. The high-strength and high-toughness welding steel wire rod containing Cu developed by the present application can reach the user's use requirements in each performance index of the deposited metal after welding performance test, realizes the substitution of imported products, and fills the domestic blank.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgy, and particularly relates to a high-strength and high-toughness Cu-containing steel wire rod for welding and a production method thereof. BACKGROUND

[0002] The bogie is a main component of a railway vehicle, and bears the working load of the installed components and the traction, braking and inertial force during the operation of the vehicle. The bogie frame is the skeleton of the bogie, and is the installation basis of other components, and is used to connect the components of the bogie and transmit forces in all directions, and is used to maintain the position of the axle in the bogie. The dynamic load borne by the bogie link frame is significantly increased, which puts higher requirements on the material of the bogie and the welding material thereof.

[0003] Currently, high-strength and high-toughness weathering steel is usually used for the bogie of a railway locomotive. The weathering steel has good atmospheric corrosion resistance, and also has good mechanical and welding properties. The commonly used materials for the bogie welded frame are Q345E, S355 series steel, SMA490 series steel and the like. The weathering steel, also known as atmospheric corrosion resistant steel, is obtained by adding a certain amount of Cu, P, Cr, Ni and other alloy elements to low-carbon steel. Through the enrichment of trace elements on the surface of the steel, a dense amorphous rust layer structure is formed to improve the density. This stable rust layer can resist the invasion of harmful ions and water vapor in the atmosphere to some extent, and prevent further corrosion of the base metal. Among the above elements, copper has the largest effect. Copper can promote the generation of a dense amorphous corrosion product protective film on the surface of the low-alloy steel, and reduce the anodic activity of the steel, thereby reducing the corrosion rate. However, the Cu-containing weathering steel cracks at the edge and corner positions during hot rolling production, and the cracking is serious. During hot rolling, the deformation of the edge and corner positions of the steel is the largest, and the residual stress is also the largest. Moreover, the edge and corner positions of the steel cool first, and the cooling speed is faster than that of other positions, so it is difficult to completely release the residual stress through recrystallization. In this case, when there are inducements for cracking at the edge and corner positions, the steel is more likely to crack, which affects the final quality of the steel.

[0004] The weathering welding material for the bogie of a railway locomotive includes CHW-55CNH, G424M21Z, TH550-NQ-II and the like. In recent years, with the continuous increase of the speed of trains in China, higher requirements are put forward for the impact performance of the bogie welded frame. From the actual use results, the bogie frame structure is complex, and the problem of unstable welding quality is more prominent, such as weld strength, low-temperature impact toughness, porosity and the like.

[0005] The Cu-containing high-strength and high-toughness steel wire rod for welding is mainly used for preparing gas shielded welding wire for welding of rail vehicle bogie, and the deposited metal impact requirement is-40 DEG C >= 47J due to the special use condition of the welding wire. Therefore, qualified weathering welding steel wire rod for rail vehicle bogie is urgently needed to meet the welding performance of rail vehicle bogie, so that the mechanical properties, impact and crack resistance of the deposited metal can meet the standard requirements, and the blank of the related welding material in the domestic market is filled. SUMMARY

[0006] Therefore, the purpose of the present application is to provide a Cu-containing high-strength and high-toughness steel wire rod for welding and a production method thereof, so as to meet the welding performance of rail vehicle bogie, so that the mechanical properties, impact and crack resistance of the deposited metal can meet the standard requirements, and the blank of the related welding material in the domestic market is filled.

[0007] In order to achieve the above purpose, the present application provides a Cu-containing high-strength and high-toughness steel wire rod for welding, which comprises the following components by weight percentage: C 0.09-0.12%, Si 0.90-1.00%, Mn 1.65-1.75%, P <= 0.010%, S <= 0.010%, Cr <= 0.10%, Ni 0.80-1.10%, Cu 0.40-0.60%, Mo <= 0.05%, Ti <= 0.01%, V 0.03-0.08%, B 0.003-0.006%, lanthanum element 0.05-0.08%, neodymium element 0.05-0.09%, and the rest is Fe and inevitable impurities.

[0008] A production method of a Cu-containing high-strength and high-toughness steel wire rod for welding, comprising the following steps:

[0009] Chemical composition setting: the weathering welding steel for rail vehicle bogie in this case adopts MnCu as the main alloy system, and adds Ni: 0.80-1.10% alloying. At present, the weathering welding steel for railway locomotive in the enterprise standard usually adopts NiCrCu system, and the Ni content is low. Since the Cu content is too high, it is not conducive to the surface quality control of the billet and the wire rod, but since the Ni: 0.80-1.10% is added, a high-melting-point NiCu enrichment layer is formed, which can prevent the product surface from producing "Cu brittle" cracks. In addition, the welding steel wire rod is innovatively added with metal element vanadium, non-metallic element boron and rare earth elements lanthanum and neodymium. The rare earth elements can effectively improve the atmospheric corrosion resistance of the product. The welding steel wire rod for rail vehicle bogie independently developed by our company successfully removes the Cr element by optimizing the composition system. Not only the mechanical properties, low-temperature impact and welding performance of the deposited metal of the welding wire meet the user's demand, but also the production cost of the wire rod is saved.

[0010] The metallographic structure of the steel wire rod is ferrite and pearlite structure.

[0011] The production method of the Cu-containing high-strength and high-toughness welding steel wire rod adopts a one-fire material process and comprises the following steps: BOF converter, LF furnace refining, VD furnace degassing, continuous casting, steel billet wind-sheltered pile cooling, shot blasting inspection + grinding, wire rod rolling, and detection.

[0012] The method of the BOF converter is to perform steelmaking by using an oxygen top-blown converter steelmaking method, and the composition of the molten steel at the end point of the converter is controlled to be C≤0.05%, P≤0.005%, and the tapping temperature is ≥1600°C; the tapping is performed while the deoxidization and alloying control and the refining slagging process control are performed.

[0013] The double-slag method is used for smelting, the temperature is raised in advance for slagging, the light-burned dolomite is used in combination with calcium oxide to increase the slag basicity to 2.7, and the pure aluminum is used for deep deoxidization at the time of tapping, and the dosage is 1.0-2.0 kg / t.

[0014] Converter smelting: the chemical composition narrow-range control technology is used for smelting by using the oxygen top-blown converter steelmaking method, the A-type molten iron is used in combination with the nickel-containing pig iron, the nickel-containing pig iron is added as scrap steel, the nickel bean addition amount in the refining process can be effectively reduced, and the nickel-containing pig iron addition amount is controlled to be 2.5 tons / oven; the double-slag method is used for smelting. The temperature is raised in advance for slagging, the light-burned dolomite is used in combination with calcium oxide to increase the slag basicity to 2.7, the high-purity aluminum bean is used for deep deoxidization at the time of tapping, the dosage is 1.0-2.0 kg / t, the oxygen content of the molten steel is reduced, and the alloy yield is improved; the alloy addition amount is accurately controlled to realize the narrow composition control of the chemical composition. The slide plate is used for slag stopping at the time of tapping to prevent the molten steel from being rephosphorized.

[0015] The components of the slag-making material added in the LF refining are 4-8 kg / t of lime and 0-3 kg / t of fluorite, so that the basicity is 2.0-5.0; the calcium carbide and the silicon-iron powder are used for diffusion deoxidization in the refining process, the weight percentage is 1:4-5, and the total addition amount is 2.1-2.5 kg / t.

[0016] LF furnace refining: the LF furnace inlet temperature is increased to 1530°C, the special welding wire steel top slag process of the company is used, 4-8 kg / t of lime and 0-3 kg / t of fluorite are used to make white slag, and the white slag time is ≥20 min. After the white slag, the welding wire steel special nickel bean, copper block, vanadium iron, and rare earth alloy are added; the manganese iron alloy is used for increasing [Mn], and the silicon iron alloy is used for increasing Si. If the Cr content in the molten steel is insufficient, the chromium iron alloy can be added. Before soft blowing, the low-aluminum titanium-iron wire and the boron-iron wire are fed in one time as much as possible, the argon flow is adjusted to make the slag surface slightly fluctuate, and the molten steel must not be exposed; the intermediate ladle carbon-free covering agent is added for heat preservation, whether the carbonized rice husk is added is determined according to the slag surface, the whole slag surface is required to be covered and evenly spread.

[0017] The VD furnace vacuum degassing controls the gas O≤30ppm, N≤60ppm, and the soft blowing time≥20 minutes. The VD vacuum degassing is used to improve the purity of the molten steel, control the gas [O]≤30ppm, [N]≤60ppm in the steel, and the inclusion A, B, C, D class is all≤1.0 level.

[0018] The VD furnace vacuum degassing: the original vacuum degree and vacuum time are improved, and are adjusted from 60MPa to 70MPa and from 5 minutes to 8 minutes. The high vacuum degree and long vacuum time are used for degassing, the O and N in the steel and the inclusion are reduced, and the purity of the molten steel is improved; the argon flow is adjusted to make the slag surface slightly fluctuate, and the molten steel should not be exposed; the carbon-free covering agent carbonized rice husk is added to the slag surface, and the whole slag surface is required to be covered and evenly spread; and the soft blowing time≥20 minutes.

[0019] The continuous casting adopts the continuous casting light press-down cast blank, and the pouring process parameters are: superheat 25~35℃, drawing speed 2.3m / min, secondary cooling system 0.8~1.0L / kg, current intensity 300~400A, and frequency 3~4Hz; the end electromagnetic stirring parameters are: current intensity 250~300A, and frequency 8~10Hz; and the light press-down amount is 3-4mm.

[0020] The continuous casting light press-down cast blank: the straight arc 160 square Danner continuous casting machine is used for protective casting, and the dynamic light press-down model is used. The function of the light press-down technology is to reduce the thickness of the cast blank by applying a certain pressure to the cast blank at the end of the liquid core, not only to compensate for the solidification shrinkage and eliminate the center porosity, but also to hinder the flow of concentrated molten steel caused by negative pressure and eliminate the center segregation. The pouring process parameters are: liquidus temperature 1530℃, superheat 25~35℃, drawing speed 2.3m / min, and heavy press-down technology is adopted, and the light press-down amount is 3-4mm, which effectively improves the internal quality of the cast blank and reduces the inclusion and segregation degree. The steel blank low-multiple center porosity, center segregation, and shrinkage hole are all≤0.5 level.

[0021] In the pit cooling, the steel blank enters the pit at a temperature of 500-650℃; the pit cooling time is≥48h, and the out-pit temperature is≤150℃.

[0022] The parameters of the wire rod rolling are: the furnace gas air-fuel ratio is 0.54~0.64, the soaking segment temperature range is 1100~1160℃, the opening rolling temperature is 980~1050℃, the final rolling temperature is 820~880℃, the wire drawing temperature is 800~830℃, the out-insulation cover temperature is 470~560℃, and the coil temperature is 370~480℃.

[0023] The welding wire steel adopts a low-temperature low-roller rolling process, the rolling control method is low-temperature line control, the roller speed is controlled at 0.1 m / s-0.2 m / s throughout the process, a heat preservation cover is added throughout the process, and all the air coolers are closed, which can effectively reduce the tensile strength of the rod, improve the area reduction of the rod, and further improve the mechanical properties of the rod.

[0024] The beneficial effects of the present application are as follows: currently, various enterprises usually adopt the electric furnace two-fire breakdown process route, the present application adopts the converter one-fire material forming process route, greatly reduces the product energy consumption and production process, successfully improves the cladding properties and atmospheric corrosion resistance of the welding wire by adding metal, non-metallic elements and rare earth elements. Through reasonable smelting and rolling process technology, the developed Cu-containing high-strength and high-toughness steel wire rod for welding, after welding performance test, the performance indicators of the deposited metal all meet the user's requirements, realizes the replacement of imported products, and fills the domestic blank. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only a part of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0026] Figure 1 It is the detection comparison chart of pickling low-magnification samples of example 1 and comparative example 1 of the present application, wherein (a) is the detection chart of the first flow pickling low-magnification sample of example 1, (b) is the detection chart of the first flow pickling low-magnification sample of comparative example 1, (c) is the detection chart of the second flow pickling low-magnification sample of example 1, and (d) is the detection chart of the second flow pickling low-magnification sample of comparative example 1;

[0027] Figure 2 It is a 500 times magnification metallographic structure view schematic diagram of the present application example and comparative example;

[0028] Figure 3 It is a same circle tensile strength curve diagram schematic diagram of example 1 and comparative example of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the following will further illustrate the present application in combination with specific embodiments.

[0030] It should be noted that unless otherwise defined, technical terms or scientific terms used in the present application shall have the common meaning understood by one of ordinary skill in the art to which the present application pertains. The terms such as "comprising" or "including" or similar terms mean that the elements or objects before the term encompass the elements or objects listed after the term and equivalents thereof, and do not exclude other elements or objects. Example 1

[0031] A Cu-containing high-strength and high-toughness welding steel wire rod, the composition of which is as follows in terms of percentage by weight: C 0.10%, Si 0.95%, Mn 1.70%, P≤0.010%, S≤0.010%, Cr≤0.10%, Ni 0.95%, Cu 0.50%, Mo≤0.05%, Ti≤0.01%, and the steel wire rod is innovatively added with non-metallic elements and rare earth elements: V element range 0.05%, B element range 0.004%, lanthanum element range 0.06%, and neodymium element range 0.07%, and the rest is Fe and unavoidable impurities.

[0032] The production method of the Cu-containing high-strength and high-toughness welding steel wire rod of the present embodiment comprises the following steps:

[0033] Step S1, steelmaking BOF: using oxygen top-blown converter steelmaking method for steelmaking, adopting MnNiCu main alloy system, smelting by double-slag method, pre-heating to form slag, using light-burned dolomite and calcium oxide to form slag with basicity increased to 2.7, and controlling the composition of the molten steel at the end of the converter to be: C≤0.05%, P≤0.005%, and the tapping temperature≥1600℃; carrying out deoxidization and alloying control and refining slagging process control at the time of tapping, and using pure aluminum for deep deoxidization with a dosage of 1.5kg / t;

[0034] Step S2, LF refining furnace: the LF refining furnace inlet temperature is 1530℃, and the slagging material is added later, the composition of the slagging material is lime 6kg / t and 2kg / t fluorite, so that the slag basicity R is 2.8, and the diffusion deoxidization is carried out by adding a small amount of ferrosilicon and silicon iron powder with a weight percentage of 1:5 on the slag surface in multiple times, the total addition amount is 2.5kg / t, the C content target is±0.01%, and the Mn, Ni and Cu element content target is±0.02%;

[0035] VD furnace degassing: improving the original vacuum degree and vacuum time, adjusting from 60MPa to 70MPa and from 5 minutes to 8 minutes; controlling the gas O≤30ppm and N≤60ppm in the steel by VD furnace vacuum degassing, and the soft blowing time is 20 minutes.

[0036] Step S3, light press down casting billet: using straight arc 160 Fangdaieli continuous casting machine for protective casting, the process parameters are: superheat 35℃, drawing speed 2.3m / min, secondary cooling system 1.0L / kg, current intensity 400A, frequency 4Hz, end electromagnetic stirring parameters: current intensity 300A, frequency 9Hz; light press down amount is 3.5mm.

[0037] Step S4, billet pit cooling: billet into pit temperature 580℃; pit cooling time 48h, out of pit temperature 150℃, in the pit left and right up and down stack position, all have hot billet;

[0038] Step S5, shot blasting and flaw detection + grinding are carried out on the billet, and the surface corner crack, scab and other defects of the billet are ground;

[0039] Step S6, wire rod rolling, the rolling control method is low temperature line control, the roller speed is controlled at 0.15m / s throughout the process, and the process parameters are: high pressure water phosphorus removal is 18Mpa, furnace gas air-fuel ratio is 0.58, soaking segment temperature range is 1140℃, 1000℃, finishing temperature is 850℃, wire drawing temperature is 815℃, out of the heat preservation cover temperature is 515℃, and the coil temperature is 425℃;

[0040] Step S7, detection qualified into warehouse. Example 2

[0041] A Cu-containing high-strength and high-toughness welding steel wire rod, the composition is as follows in terms of percentage by weight: C 0.09%, Si 0.90%, Mn 1.65%, P≤0.010%, S≤0.010%, Cr≤0.10%, Ni 0.80%, Cu 0.40%, Mo≤0.05%, Ti≤0.01%, the weather-resistant welding steel innovatively adds non-metallic elements and rare earth elements: V element range 0.03%, B element range 0.003%, lanthanum element range 0.05%, neodymium element range 0.05%, and the rest is Fe and unavoidable impurities.

[0042] The production method of the Cu-containing high-strength and high-toughness welding steel wire rod of the embodiment includes the following steps:

[0043] Step S1, steelmaking BOF: using oxygen top-blown converter steelmaking method for steelmaking, using MnNiCu main alloy system, smelting by double slag method, preheating to form slag, using light-burned dolomite and calcium oxide to form slag with basicity increased to 2.7, through converter end point control, the composition of the molten steel is: C≤0.05%, P≤0.005%, and the tapping temperature is≥1600℃; deoxidation and alloying control and refining slag process control are carried out during tapping, pure aluminum is used for deep deoxidation with a dosage of 1.0kg / t;

[0044] Step S2, LF refining furnace: the LF refining furnace inlet temperature is 1550°C, and a slagging material is added afterwards, the components of the slagging material are lime 4 kg / t and 1 kg / t fluorite, so that the slag basicity R is 2.1, and the refining process adopts calcium carbide and ferrosilicon powder with a weight percentage of 1:4 for diffusion deoxidation, which is added in small amounts and multiple times on the slag surface, and the total addition amount is 2.1 kg / t, the C content target is ±0.01%, and the Mn, Ni and Cu element content target is ±0.02%;

[0045] VD furnace degassing: the original vacuum degree and vacuum time are improved, and the vacuum degree is adjusted from 60 MPa to 70 MPa and the vacuum time is adjusted from 5 minutes to 8 minutes; the VD furnace vacuum degassing controls the gas in the steel to be O≤30 ppm and N≤60 ppm, and the soft blowing time is 25 minutes.

[0046] Step S3, light press-down casting billet: using a straight arc 160 square Danner continuous casting machine for protective casting, the process parameters are: superheat 30°C, drawing speed 2.2 m / min, secondary cooling system 0.8 L / kg, current intensity 300 A, frequency 3 Hz, and the end electromagnetic stirring parameters are: current intensity 250 A, frequency 8 Hz; the light press-down amount is 3 mm.

[0047] Step S4, billet pit cooling: the billet pit temperature is 500°C; the pit cooling time is 52 h, the out-pit temperature is 140°C, and there are hot billets in the left and right upper and lower stacks in the pit;

[0048] Step S5, shot blasting and flaw detection are performed on the billet, and the surface corner cracks and scarring defects of the billet are ground;

[0049] Step S6, wire rod rolling, the rolling control method is low temperature line control, the roller speed is controlled at 0.1 m / s throughout the process, and the process parameters are: high pressure water phosphorus removal is 18 MPa, furnace gas air-fuel ratio is 0.54, soaking segment temperature range is 1100°C, 980°C, finish rolling temperature is 820°C, wire drawing temperature is 800°C, out of the heat shield temperature is 470°C, and the coil temperature is 380°C;

[0050] Step S7, detection qualified into the warehouse. Example 3

[0051] A Cu-containing high-strength and high-toughness steel wire rod for welding, the components are as follows in terms of weight percentage: C 0.12%, Si 1.00%, Mn 1.75%, P≤0.010%, S≤0.010%, Cr≤0.10%, Ni 1.10%, Cu 0.60%, Mo≤0.05%, Ti≤0.01%, and the weather-resistant welding wire steel innovatively adds non-metallic elements and rare earth elements: V element range 0.08%, B element range 0.006%, lanthanum element range 0.08%, neodymium element range 0.08%, and the rest is Fe and unavoidable impurities.

[0052] The production method of the Cu-containing high-strength and high-toughness welding steel wire rod of the embodiment comprises the following steps:

[0053] Step S1, steelmaking BOF: using oxygen top-blown converter steelmaking method for steelmaking, adopting MnNiCu main alloy system, smelting by double-slag method, preheating to form slag, using light-burned dolomite to match calcium oxide to increase the slag basicity to 2.7, controlling the steel composition at the converter endpoint to be: C≤0.05%, P≤0.005%, and the tapping temperature to be≥1600℃; carrying out deoxidization and alloying control and refining and slagging process control at the time of tapping, using pure aluminum for deep deoxidization at the time of tapping, and the dosage is 2.0 kg / t;

[0054] Step S2, LF refining furnace: the LF refining furnace inlet temperature is 1540℃, and the slagging material is added later, the components of the slagging material are lime 8 kg / t and 3 kg / t fluorite, so that the slag basicity R is 3.0, and the diffusion deoxidization is carried out by using calcium carbide and silicon-iron powder with a weight percentage of 1:5 in the refining process, and the total addition amount is 2.5 kg / t, the C content target is ±0.01%, and the Mn, Ni and Cu element content target is ±0.02%;

[0055] VD furnace degassing: improving the original vacuum degree and vacuum time, adjusting from 60 MPa to 70 MPa, and adjusting from 5 minutes to 8 minutes; the VD furnace vacuum degassing controls the gas O in the steel to be≤30 ppm, and N≤60 ppm, and the soft blowing time is 25 minutes.

[0056] Step S3, light press-down pouring billet: using straight-arc 160 square Danner continuous casting machine for protective casting, and the pouring process parameters are: superheat 33℃, pulling speed 2.3 m / min, secondary cooling system 1.0 L / kg, current intensity 400 A, frequency 4 Hz, and the end electromagnetic stirring parameters are: current intensity 300 A, frequency 10 Hz; the light press-down amount is 3.8 mm.

[0057] Step S4, billet pit cooling: the billet inlet pit temperature is 620℃; the pit cooling time is 55 h, the pit outlet temperature is 130℃, and there are hot billets in the left and right upper and lower stacks in the pit;

[0058] Step S5, shot blasting and flaw detection are carried out on the billet, and the surface corner cracks, scarring and other defects of the billet are ground;

[0059] Step S6, wire rod rolling, the rolling control method is low-temperature line control, the roller speed is controlled at 0.2 m / s throughout the process, and the rolling process parameters are: high-pressure water phosphorus removal is 18 Mpa, furnace gas air-fuel ratio is 0.62, soaking segment temperature range is 1150℃, 1020℃, finish rolling temperature is 870℃, wire drawing temperature is 820℃, the temperature out of the heat preservation cover is 530℃, and the coil temperature is 450℃;

[0060] Step S7, detecting qualified storage.

[0061] Comparative Example 1

[0062] The difference between the present comparative example and Example 1 is that the step S1 controls the composition of the molten steel by converter end-point control to be: C: 0.06%, P: 0.006%, and the tapping temperature is 1550℃; and the deoxidation alloying control and the refining slagging process control are performed at the time of tapping.

[0063] The step S2 adds a slagging material after entering the LF refining furnace, the composition of the slagging material is lime 8kg / t, fluorite 5kg / t, so that the slag has good fluidity and the basicity R is 2.0; the diffusion deoxidation is performed by using calcium carbide and ferrosilicon powder with a weight percentage of 1:3 in the refining process, and the total addition amount is 2.0kg / t; the C content target is ±0.01%, and the Mn, Ni, Cr, Mo and other element content targets are ±0.02%.

[0064] Step S3, light pressing down and casting billet: the continuous casting machine is used to cast the billet, and the process parameters are: superheat 40℃, casting speed 2.5m / s, secondary cooling system 1.0L / kg, current intensity 400A, frequency 4Hz, and the end electromagnetic stirring parameters are: current intensity 300A, frequency 9Hz; the light pressing down amount is 3.5mm. The light pressing down technology is not used.

[0065] Step S6, wire rod rolling, and the process parameters are: high-pressure water phosphorus removal 16Mpa, furnace gas air-fuel ratio 0.50, soaking segment temperature range 1200℃, 1000℃, finish rolling temperature 950℃, wire rod temperature 850℃, out of the holding cover temperature 580℃, and the coil collecting temperature 500℃.

[0066] Effect comparison:

[0067] Figure 1 The pickling macrographs of the Example 1 and the Comparative Example 1 are detected, wherein (a) is the detection graph of the first flow pickling macrograph of Example 1, (b) is the detection graph of the first flow pickling macrograph of Comparative Example 1, (c) is the detection graph of the second flow pickling macrograph of Example 1, and (d) is the detection graph of the second flow pickling macrograph of Comparative Example 1. It can be seen from the above that the Example 1 is obviously better than the Comparative Example 1. Figure 1 It can be shown that the refining improves the slag amount in the steelmaking process, and the light pressing down technology is used in the continuous casting, which can effectively eliminate the center segregation and center shrinkage hole of the billet. It is not difficult to find that the shrinkage hole of the billet in the Example is obviously smaller than that in the Comparative Example. The shrinkage hole of the billet seriously affects the rolling process of the billet, and the shrinkage hole of the finished wire rod is too large. Due to the influence of the center tension, the core organization is hollow during the processing of the downstream customer due to high-speed drawing, and the wire breaking affects the production rhythm. Therefore, the billet of Example 1 is obviously better than that of the Comparative Example.

[0068] Figure 2The metallographic structure of Example 1 of the present application and Comparative Example 1 is shown in a 500 times enlarged view, and it can be seen from the comparison that, in the steelmaking process, the refining slag amount is increased, the light press-down technology is used in continuous casting, and the low-temperature slow roller way controlled rolling and controlled cooling technology is used in steel rolling, so that the metallographic structure in the example is more uniform, which is ferrite and pearlite structure, and the metallographic structure in the comparative example is ferrite, pearlite and bainite structure; the existence of bainite is not conducive to the drawing of downstream customers, and can increase the risk of wire breakage in drawing of customers, and the subsequent customer trial.

[0069] The same circle tensile strength range is the difference between the highest tensile strength and the lowest tensile strength of 8 samples obtained by cutting a whole circle into 8 samples for mechanical test.

[0070] Table 1: Comparison of mechanical properties of the same circle of Example 1-3 and Comparative Example

[0071]

[0072] Figure 3 The same circle mechanical property curve of Example 1 of the present application is shown in a schematic view, and it can be seen from the comparison that, in the steelmaking process, the refining slag amount is increased, the light press-down technology is used in continuous casting, and the low-temperature slow roller way controlled rolling and controlled cooling technology is used in steel rolling, so that the tensile strength of the same circle of the example is lower, and the average tensile strength is 750 Mpa, and the tensile strength of the comparative example is higher, which is 950 Mpa, it can be seen that the low-temperature slow roller way rolling can obviously improve the mechanical properties of the same circle of the wire rod, and the lower tensile strength is more conducive to drawing, and the user can save the annealing cost.

[0073] The steel wire rods produced in Example 1 and Comparative Example 1 of the present application are applied in actual application, and the welding performance test evaluation is carried out, and the use data obtained is shown in Table 2.

[0074] Table 2: Comparison of application of Example and Comparative Example

[0075]

[0076] It can be seen from the results in Table 2 that the steel wire rod prepared in the present application is easier to draw, and is not easy to break, and does not need annealing process, and the welding test evaluation is good, and the low-temperature impact performance is excellent.

[0077] It should be understood by those skilled in the art that the above discussion of any of the embodiments is only exemplary, and is not intended to imply that the scope of the present application is limited to these examples; the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in detail for the sake of brevity. Any omissions, modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A Cu-containing high-strength high-ductility welding steel wire rod, characterized in that, The steel wire rod comprises the following ingredients by weight percentage: C 0.09-0.12%, Si 0.90-1.00%, Mn 1.65-1.75%, P≤0.010%, S≤0.010%, Cr≤0.10%, Ni 0.80-1.10%, Cu 0.40-0.60%, Mo≤0.05%, Ti≤0.01%, V 0.03-0.08%, B 0.003-0.006%, lanthanum element 0.05-0.08%, neodymium element 0.05-0.09%, and the rest is Fe and inevitable impurities, and the metallographic structure of the steel wire rod is ferrite and pearlite structure, the continuous casting adopts a continuous casting light press-down cast blank, the roller speed is controlled at 0.1 m / s-0.2 m / s in the whole rolling process, a cover is added to the whole heat preservation cover, and all the air coolers of the air cooling line are closed.

2. The method of production of a Cu-bearing high-strength high-ductility welding steel rod according to claim 1, characterized in that, The production method adopts a pyrogenic material process and comprises the following steps: BOF converter, LF furnace refining, VD furnace degassing, continuous casting, steel blank wind pit cooling, shot blasting inspection + grinding, wire rod rolling, and detection; the continuous casting adopts a continuous casting light press-down cast blank, and the pouring process parameters are as follows: superheat 25-35 DEG C, pulling speed 2.3 m / min, secondary cooling system 0.8-1.0 L / kg, current intensity 300-400 A, and frequency 3-4 Hz; the end electromagnetic stirring parameters are as follows: current intensity 250-300 A and frequency 8-10 Hz; the light press-down amount is 3-4 mm, the roller speed is controlled at 0.1 m / s-0.2 m / s in the whole rolling process, the whole heat preservation cover is covered, and all the air coolers of the air cooling line are closed.

3. The method of production of a Cu-bearing high-strength high-ductility welding steel rod according to claim 2, characterized in that, The method of the BOF converter is to carry out steelmaking by adopting an oxygen top-blown converter steelmaking method, and the composition of the molten steel at the end point of the converter is controlled to be as follows: C≤0.05%, P≤0.005%, and the tapping temperature is≥1600 DEG C; the deoxidization alloying control and the refining slagging process control are carried out at the time of tapping.

4. The method of production of a Cu-bearing high-strength high-ductility welding steel rod according to claim 3, characterized in that, The steel is smelted by a double-slag method, the temperature is raised in advance to form slag, light-burned dolomite is used to form slag in combination with calcium oxide, the slag basicity is increased to 2.7, pure aluminum is used for deep deoxidization at the time of tapping, and the dosage is 1.0-2.0 kg / t.

5. The method of production of a Cu-bearing high-strength high-ductility welding steel rod according to claim 2, characterized in that, The slagging material components added in the LF furnace refining are as follows: lime 4-8 kg / t and 0-3 kg / t fluorite, so that the basicity is 2.0-5.0; the calcium carbide and silicon-iron powder are used for diffusion deoxidization in the refining process, the weight percentage is 1:4-5, and the total addition amount is 2.1-2.5 kg / t.

6. The method of production of a Cu-bearing high-strength high-ductility welding steel rod according to claim 2, characterized in that, The VD furnace vacuum degassing controls the gas O≤30 ppm and N≤60 ppm in the steel.

7. The method of production of a Cu-bearing high-strength high-ductility welding steel rod according to claim 2, characterized in that, The pit cooling is carried out at the steel blank temperature of 500-650 DEG C, the pit cooling time is≥48 h, and the out-pit temperature is≤150 DEG C.

8. The method of production of a Cu-bearing high-strength high-ductility welding steel rod according to claim 2, characterized in that, The wire rod rolling parameters are as follows: furnace gas air-fuel ratio 0.54-0.64, soaking section temperature range 1100-1160 DEG C, opening rolling temperature 980-1050 DEG C, final rolling temperature 820-880 DEG C, wire drawing temperature 800-830 DEG C, out-heat preservation cover temperature 470-560 DEG C, and coil collecting temperature 370-480 DEG C.

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