A low-spatter high-speed drawn welding wire steel wire rod and its preparation method

Abstract

The present invention provides a low-spatter, high-speed drawn welding steel wire rod and a preparation method thereof. During the preparation process of the welding steel wire rod, the wire drawing temperature is controlled to be 870-905°C; the temperature of the intermediate wire rod exiting the Stelmor cooling line is ≤600°C; and the temperature of the welding steel wire rod exiting the coil conveying line is ≥350°C. The low-spatter, high-speed drawn welding steel wire rod prepared by the aforementioned preparation method has an Fe2SiO4 layer in its oxide scale having a thickness of less than 9% of the total oxide scale thickness, and a FeO layer having a thickness of more than 40% of the total oxide scale thickness. The total oxide scale thickness of the welding steel wire rod is 10-15μm. The present invention improves the drawing speed of the welding steel wire rod while ensuring its welding performance.

Description

Technical Field

[0001] The present invention relates to the technical field of welding wire steel, and in particular to a low-splash, high-speed drawn welding wire steel wire rod and a preparation method thereof. Background Art

[0002] Gas shielded welding wire is typically drawn from 5.5mm diameter wire rod. Faced with increasingly fierce industry competition and production cost pressures, wire manufacturers urgently need to increase wire drawing speeds during processing to improve production efficiency. Currently, conventional drawing speeds for gas shielded welding wire steel on the market range from 12-20 m / s, with some emerging production lines capable of exceeding 30 m / s. This, in turn, places higher standards and requirements on the performance of the wire rod, particularly those related to drawing speed.

[0003] The preparation method of welding steel wire rod generally includes the following steps: rolling and spinning the continuous cast steel billet to obtain an intermediate wire rod with a diameter of 5.5 mm, and then the intermediate wire rod enters the Stelmor cooling line for cooling. After the intermediate wire rod exits the Stelmor cooling line, it enters the coiling area. After coiling, it is output through the coiling conveyor line to obtain the finished wire rod, that is, the welding steel wire rod. Plastic toughness is the key factor that determines whether the welding steel wire rod is suitable for the high-speed drawing production line. In order to improve the drawing performance of the welding steel wire rod, the conventional practice in the industry is to reduce the cooling rate of the intermediate wire rod after rolling, thereby reducing the strength of the welding steel wire rod and improving the plastic toughness of the welding steel wire rod. However, while reducing the cooling rate, the oxide scale structure of the welding steel wire rod finally obtained will change significantly, making the oxide scale difficult to remove, the surface blackened after copper plating, and the spatter larger, which seriously affects the welding process performance. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that it is difficult to increase the wire rod drawing speed while ensuring its welding performance.

[0005] To this end, a method for preparing low-splash, high-speed drawn welding wire steel wire rod is provided. During the preparation process of the welding wire steel wire rod, the wire drawing temperature is controlled to be 870-905°C; the temperature of the intermediate wire rod leaving the Stelmor cooling line is ≤600°C; and the temperature of the welding wire steel wire rod leaving the coil transport line is ≥350°C.

[0006] Optionally, the Stelmore cooling line includes ten cooling sections. During the cooling process, all fans of the Stelmore cooling line are kept closed, the heat preservation covers of the first cooling section and the second cooling section are opened, and the heat preservation covers of the remaining cooling sections are closed.

[0007] In the Stelmor cooling line, the temperature of the intermediate wire rod when entering the third cooling section is ≥780℃; the roller speed of the Stelmor cooling line is 0.1-0.13m / s.

[0008] Optionally, in the Stelmor cooling line, the cooling rate of the intermediate wire rod in the ferrite phase transformation zone is controlled to be 0.6-0.9°C / s.

[0009] The welding steel wire rod prepared by the above-mentioned method for preparing low-splash high-speed drawn welding steel wire rod has an Fe2SiO4 layer thickness in the oxide scale of the welding steel wire rod that is less than 9% of the total oxide scale thickness, and an FeO layer thickness that is more than 40% of the total oxide scale thickness. The total oxide scale thickness of the welding steel wire rod is 10-15 μm.

[0010] Optionally, the welding wire steel wire rod contains impurity elements Al < 0.004% and Ca ≤ 0.0008% by weight.

[0011] Furthermore, the welding wire steel wire rod comprises, by weight percentage, C 0.05-0.08%, Si 0.6-0.9%, Mn 1.4-1.6%, Al < 0.004%, Ca ≤ 0.0008%, and the balance is Fe and other inevitable impurities.

[0012] Optionally, the maximum inclusion size of the welding steel wire rod is ≤15μm.

[0013] Optionally, the tensile strength of the welding steel wire rod is ≤520MPa, and the cross-sectional shrinkage rate is ≥85%.

[0014] Optionally, the volume ratio of ferrite in the structure of the welding steel wire rod is ≥70%, the volume ratio of martensite-austenite is ≤5%, and the grain size of the welding steel wire rod is ≥9 levels.

[0015] The above scheme is described in detail as follows:

[0016] 1. The inventors have found that the thicker the oxide scale of the welding wire steel wire rod, the easier it is to peel off the oxide scale. However, easy peeling does not mean easy to peel off cleanly. The silicon content of the gas shielded welding wire is relatively high. Under certain cooling conditions, the thickness of the innermost layer Fe2SiO4 of the oxide scale and the degree of pitting corrosion on the substrate surface increase with the increase of the total thickness of the oxide scale. In addition, the thicker the FeO layer adjacent to Fe2SiO4, the easier it is to drive the Fe2SiO4 layer to fall off. Therefore, whether the oxide scale is easy to peel off cleanly is determined by the total thickness of the oxide scale, the thickness of the innermost layer Fe2SiO4 and the thickness of the FeO layer. Therefore, the present invention clearly provides a detailed explanation of the three points of the oxide scale structure: the total thickness of the oxide scale, the thickness of the innermost layer Fe2SiO4 and the thickness of the FeO layer.

[0017] 2. In addition to affecting the wire breakage rate during drawing, the size of inclusions also plays a vital role in welding spatter. The present invention provides an appropriate definition of the size of inclusions;

[0018] 3. The technical proposal clarifies the two key impurity elements (Ca and Al) that affect welding spatter and their contents.

[0019] The technical solution of the present invention has the following advantages:

[0020] 1. The present invention provides a method for preparing low-spatter, high-speed drawn welding steel wire rod. The method comprises controlling the wire drawing temperature to 870-905°C during the wire drawing process; maintaining the intermediate wire rod temperature at ≤600°C upon exiting the Stelmor cooling line; and maintaining the wire rod temperature at ≥350°C upon exiting the coil conveyor line. Controlling the wire drawing temperature and cooling process allows for control of the structure of the wire rod oxide scale, making it easier to remove and preventing increased spatter during welding. This increases the drawing speed of the resulting wire rod while maintaining weldability.

[0021] 2. The present invention provides a low-spatter, high-speed drawn welding steel wire rod, wherein the welding steel wire rod has a tensile strength of ≤520 MPa, a cross-sectional reduction rate of ≥85%, a ferrite ratio of ≥70%, an MA (martensite-austenite) structure ratio of ≤5%, a grain size of ≥9, a maximum inclusion size of ≤15 μm, a thickness of the Fe2SiO4 layer in the oxide scale of less than 9% of the total oxide scale thickness, a thickness of the FeO layer of more than 40% of the total oxide scale thickness, and a total oxide scale thickness of 10-15 μm. The welding steel wire rod can be adapted to a welding wire production line with a drawing speed of up to 30 m / s, a wire breakage rate of ≤0.09 times / ton, does not turn black after copper plating, and has a spatter rate of ≤2.8%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is the metallographic structure diagram of the low-splash high-speed drawn welding steel wire rod prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0025] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0026] Example 1

[0027] This embodiment provides a method for preparing a low-spatter, high-speed drawn welding wire steel wire rod, comprising the following steps:

[0028] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 870°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0029] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.12 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first cooling section and the second cooling section are opened, and the insulation covers of the remaining eight cooling sections are closed. The temperature of the intermediate wire rod entering the third cooling section is 785°C, the cooling rate of the ferrite phase transformation zone is 0.8°C / s, and the temperature of the intermediate wire rod leaving the Stelmor cooling line is 565°C.

[0030] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is maintained at 360°C when it exits the insulation corridor.

[0031] Example 2

[0032] This embodiment provides a method for preparing a low-spatter, high-speed drawn welding wire steel wire rod, comprising the following steps:

[0033] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 880°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0034] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.11 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first cooling section and the second cooling section are opened, and the insulation covers of the remaining eight cooling sections are closed. The temperature of the intermediate wire rod entering the third cooling section is 797°C, the cooling rate of the ferrite phase transformation zone is 0.7°C / s, and the temperature of the intermediate wire rod leaving the Stelmor cooling line is 560°C.

[0035] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is maintained at 350°C when it exits the insulation corridor.

[0036] Example 3

[0037] This embodiment provides a method for preparing a low-spatter, high-speed drawn welding wire steel wire rod, comprising the following steps:

[0038] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 905°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0039] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.1 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first cooling section and the second cooling section are opened, and the insulation covers of the remaining eight cooling sections are closed. The temperature of the intermediate wire rod entering the third cooling section is 780°C, the cooling rate of the ferrite phase transformation zone is 0.6°C / s, and the temperature of the intermediate wire rod leaving the Stelmor cooling line is 580°C.

[0040] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is maintained at 370°C when it exits the insulation corridor.

[0041] Example 4

[0042] This embodiment provides a method for preparing a low-spatter, high-speed drawn welding wire steel wire rod, comprising the following steps:

[0043] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 905°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0044] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.13 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first cooling section and the second cooling section are opened, and the insulation covers of the remaining eight cooling sections are closed. The temperature of the intermediate wire rod entering the third cooling section is 890°C, the cooling rate of the ferrite phase transformation zone is 0.9°C / s, and the temperature of the intermediate wire rod leaving the Stelmor cooling line is 600°C.

[0045] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is 395°C when it exits the insulation corridor.

[0046] Example 5

[0047] This embodiment provides a method for preparing a low-spatter, high-speed drawn welding wire steel wire rod, comprising the following steps:

[0048] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 875°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0049] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.12 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first cooling section and the second cooling section are opened, and the insulation covers of the remaining eight cooling sections are closed. The temperature of the intermediate wire rod entering the third cooling section is 800°C, the cooling rate of the ferrite phase transformation zone is 0.7°C / s, and the temperature of the intermediate wire rod leaving the Stelmor cooling line is 570°C.

[0050] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is maintained at 380°C when it exits the insulation corridor.

[0051] Example 6

[0052] This embodiment provides a method for preparing a low-spatter, high-speed drawn welding wire steel wire rod, comprising the following steps:

[0053] A continuous cast steel billet with a cross section of 140×140 mm, the composition of which is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 900°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0054] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.12 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first cooling section and the second cooling section are opened, and the insulation covers of the remaining eight cooling sections are closed. The temperature of the intermediate wire rod entering the third cooling section is 790°C, the cooling rate of the ferrite phase transformation zone is 0.8°C / s, and the temperature of the intermediate wire rod leaving the Stelmor cooling line is 590°C.

[0055] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is greater than 385°C when it exits the insulation corridor.

[0056] Comparative Example 1

[0057] This comparative example provides a method for preparing a low-spatter, high-speed drawn welding steel wire rod, comprising the following steps:

[0058] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 930°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0059] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.12 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first and second cooling sections are opened, and the insulation covers of the remaining cooling sections are closed. The temperature of the wire rod entering the third cooling section is 850°C, the cooling rate of the ferrite phase transformation zone is 0.8°C / s, and the temperature of the wire rod leaving the Stelmor cooling line is 660°C.

[0060] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is kept at 420°C when it exits the insulation corridor.

[0061] Comparative Example 2

[0062] This comparative example provides a method for preparing a low-spatter, high-speed drawn welding steel wire rod, comprising the following steps:

[0063] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 870°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0064] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.12 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first four cooling sections are all opened, and the insulation covers of the remaining six cooling sections are all closed. The temperature of the intermediate wire rod entering the fifth cooling section is 708°C, the cooling rate of the ferrite phase transformation zone is 1.4°C / s, and the temperature out of the Stelmor cooling line is 480°C.

[0065] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is maintained at 310°C when it exits the insulation corridor.

[0066] Comparative Example 3

[0067] This comparative example provides a method for preparing a low-spatter, high-speed drawn welding steel wire rod, comprising the following steps:

[0068] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 860°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0069] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.12 m / s, all fans of the Stelmor cooling line are kept closed, and all insulation covers are closed. The temperature of the intermediate wire rod entering the first cooling section is 820°C, the cooling rate of the ferrite phase transformation zone is 0.5°C / s, and the temperature of the intermediate wire rod exiting the Stelmor cooling line is 630°C.

[0070] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is maintained at 390°C when it exits the insulation corridor.

[0071] Comparative Example 4

[0072] This comparative example provides a method for preparing a low-spatter, high-speed drawn welding steel wire rod, comprising the following steps:

[0073] A continuous cast steel billet with a cross section of 140×140 mm, whose composition is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 870°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0074] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.13 m / s, and all fans of the Stelmor cooling line are kept closed. The insulation covers of the first and second cooling sections are opened, and the insulation covers of the remaining eight cooling sections are closed. The temperature of the intermediate wire rod entering the third cooling section is 790°C, the cooling rate of the ferrite phase transformation zone is 0.8 / s, and the temperature of the intermediate wire rod leaving the Stelmor cooling line is 580°C.

[0075] After exiting the Steyr cooling line, the wire rod enters the coiling area, where it is hung on a C-shaped hook and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. No insulation corridors are built above or on both sides of the coiling area and the coil conveyor line. A temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hook to 0.5m / s, the temperature of the welding wire steel wire rod is 150°C when it exits the insulation corridor.

[0076] Comparative Example 5

[0077] This comparative example provides a method for preparing a low-spatter, high-speed drawn welding steel wire rod, comprising the following steps:

[0078] A continuous cast steel billet with a cross section of 140×140 mm, the composition of which is shown in Table 1, was obtained. The continuous cast steel billet was heated to 1060°C for rolling and then spun at 900°C to obtain an intermediate wire rod with a diameter of 5.5 mm.

[0079] The intermediate wire rod is cooled in a Stelmor cooling line, which includes ten cooling sections. During the cooling process, the roller speed of the Stelmor cooling line is set to 0.16 m / s, all fans of the Stelmor cooling line are kept closed, and all insulation covers are opened. The cooling rate of the intermediate wire rod in the ferrite phase transformation zone is 2.2°C / s, and the temperature out of the Stelmor cooling line is 350°C.

[0080] After exiting the Steyr cooling line, the intermediate wire rod enters the coiling area, where it is hung on C-shaped hooks and transported through the coil conveyor line to obtain the finished wire rod, namely the welding wire steel wire rod. Insulated corridors are constructed above and on both sides of the coiling area and the coil conveyor line, and a temperature gauge is installed at the end of the coil conveyor line. By controlling the transport speed of the C-shaped hooks to 0.5m / s, the temperature of the welding wire steel wire rod is kept at 210°C when it exits the insulation corridor.

[0081] Table 1

[0082]

[0083] Test Example 1

[0084] The oxide scale structure of the low-splash high-speed drawn welding steel wire rod prepared in each embodiment and comparative example was tested for thickness by scanning electron microscopy. The oxide scale included Fe2SiO4 layer, FeO layer, Fe3O4 layer and Fe2O3 layer from the inside to the outside. The thickness of the oxide scale, Fe2SiO4 layer and FeO layer are shown in Table 2.

[0085] Test Example 2

[0086] The size of the largest inclusions in the low-spatter high-speed drawn welding wire steel wire rods prepared in each embodiment and comparative example was tested using a Zeiss field emission scanning electron microscope. The test results are shown in Table 2.

[0087] Table 2

[0088]

[0089] Test Example 3

[0090] The tensile strength and cross-sectional reduction rate of the low-spatter high-speed drawn welding steel wire rods prepared in each embodiment and comparative example were tested using a 5kN electronic universal material testing machine. The test results are shown in Table 3.

[0091] Test Example 4

[0092] The metallographic characteristics of the low-spatter high-speed drawn welding wire steel wire rods prepared in each embodiment and comparative example were performed using an optical microscope, the grain size levels were recorded, and the volume ratios of ferrite and martensite-austenite (MA) in the wire rod structure were calculated. Figure 1 TABLE 3 Metallographic structure of the low-spatter high-speed drawn welding wire steel wire rod prepared in Example 1. Other test results are shown in Table 3.

[0093] Table 3

[0094]

[0095] Test Example 5

[0096] The low-sputter, high-speed drawn welding wire steel wire rod prepared in each embodiment and comparative example was drawn into a gas shielded welding wire with a diameter of 1.2 mm. Carbon dioxide gas shielded welding was performed on a flat plate with a welding current of 300±30 A, a voltage of 29±2 V, and a welding heat input of 13 kJ / cm. After welding, metal spatter particles around the weld were collected and the weight A (kg) was measured. The welding material consumed during the welding process was B (kg). The spatter rate was calculated using the formula = A / B*100%. The test results are shown in Table 4.

[0097] Test Example 6

[0098] The drawing performance of the low-splash, high-speed drawn welding steel wire rods prepared in each embodiment and comparative example was tested. The wire rods were not annealed or heat treated before drawing, but were directly pickled. The wire rods were then roughly drawn to a wire rod diameter of 2.45 mm and then finely drawn to a wire rod diameter of 1.2 mm. During the drawing process, the number of breaks in drawing 10 tons of wire rods was counted, and the wire breakage rate was calculated. The test results are shown in Table 4.

[0099] Table 4

[0100]

[0101] The welding wire steel wire rod prepared in Examples 1-6 has a tensile strength of ≤520 MPa, a cross-sectional shrinkage rate of ≥85%, can adapt to a welding wire production line with a drawing speed of up to 30 m / s, a wire breakage rate of ≤0.09 times / ton, does not turn black after copper plating, and a spatter rate of ≤2.8%.

[0102] The wire rods prepared in Comparative Examples 1 and 2 had low spatter rates, but high wire breakage rates during high-speed drawing. The wire rods prepared in Comparative Example 3 had low wire breakage rates, but high spatter rates. The wire rods prepared in Comparative Examples 4 and 5 had high wire breakage rates and high spatter rates.

[0103] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a low-spatter high-speed drawn welding wire steel wire rod, characterized in that: During the preparation of welding wire steel wire rod, the wire drawing temperature is controlled at 870-905℃; the temperature of the intermediate wire rod leaving the Stelmor cooling line is ≤600℃; the temperature of the welding wire steel wire rod leaving the coil conveying line is ≥350℃; The Stelmor cooling line includes ten cooling sections. During the cooling process, all fans of the Stelmor cooling line are kept closed, the heat insulation covers of the first cooling section and the second cooling section are opened, and the heat insulation covers of the remaining cooling sections are closed. In the Stelmor cooling line, the temperature of the intermediate wire rod entering the third cooling section is ≥780°C; the roller speed of the Stelmor cooling line is 0.1-0.13m / s; In the Stelmor cooling line, the cooling rate of the intermediate wire rod in the ferrite phase transformation zone is controlled to be 0.6-0.9℃ / s.

2. The welding steel wire rod prepared by the method for preparing a low-spatter high-speed drawn welding steel wire rod according to claim 1 is characterized in that: The thickness of the Fe2SiO4 layer in the oxide scale of the welding wire steel wire rod is less than 9% of the total oxide scale thickness, the thickness of the FeO layer is more than 40% of the total oxide scale thickness, and the total oxide scale thickness of the welding wire steel wire rod is 10-15 μm.

3. The welding steel wire rod according to claim 2, characterized in that: Calculated by weight percentage, the impurity elements Al in the welding wire steel wire rod are less than 0.004% and Ca is less than or equal to 0.0008%.

4. The welding steel wire rod according to claim 2 or 3, characterized in that: The maximum inclusion size of the welding wire steel wire rod is ≤15μm.

5. The welding steel wire rod according to claim 2, characterized in that: The tensile strength of the welding wire steel wire rod is ≤520MPa, and the cross-sectional shrinkage rate is ≥85%.

6. The welding steel wire rod according to claim 2, characterized in that: The volume ratio of ferrite in the structure of the welding wire steel wire rod is ≥70%, the volume ratio of martensite-austenite is ≤5%, and the grain size of the welding wire steel wire rod is ≥9 levels.

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