Steel H08Mn2E for submerged arc welding wire and preparation method of steel H08Mn2E

Abstract

The invention discloses steel H08Mn2E for a submerged-arc welding wire and a preparation method thereof.The steel for the submerged-arc welding wire mainly comprises, by mass, 0.05%-0.10% of C, smaller than or equal to 0.07% of Si, 1.50%-1.90% of Mn, smaller than or equal to 0.015% of P, smaller than or equal to 0.010% of S and 0.35%-0.45% of Ni, the quality of a wire rod of the steel H08Mn2E for the submerged-arc welding wire is effectively improved, the mechanical property and the steel purity of the wire rod are guaranteed through the low-sulfur-phosphorus high-manganese component design, and the steel quality of the submerged-arc welding wire is improved. And a proper amount of Ni element is added to improve the weld toughness and ensure the weld quality. In the preparation method, crystallizer electromagnetic stirring is adopted for continuous casting, the surface quality of a casting blank is improved, and internal cracks and center defects are reduced; a metallographic structure composed of ferrite and pearlite is obtained through a steel rolling stelmor controlled rolling and controlled cooling process in combination with a slow cooling process; not only is the mechanical property of the H08Mn2E wire rod guaranteed, but also the drawing property of the H08Mn2E wire rod is guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of metallurgy and material technology, and specifically relates to H08Mn2E steel for submerged arc welding wire and a preparation method thereof. Background Art

[0002] H08Mn2E steel for submerged arc welding wire is a low sulfur and phosphorus high manganese welding wire, mainly used for welding structures with higher toughness requirements; it is an ideal welding material for bridges, ships, pressure vessels, engineering machinery and steel structures in high-cold areas; the weld has beautiful shape and excellent slag removal.

[0003] With the continuous expansion of the application scope of automatic welding equipment and the improvement of automatic welding technology, the proportion of large components using submerged arc welding is increasing, and the demand for submerged arc welding wire is rising. Submerged arc welding has a series of characteristics such as high welding production efficiency, stable and reliable welding quality, and good working conditions for operators. It has been widely used and can be applied to many important welding structures. Summary of the invention

[0004] The purpose of the present invention is to produce H08Mn2E steel for submerged arc welding wire by adopting the process route of "converter + LF refining + billet continuous casting + heating furnace heating + controlled rolling and controlled cold rolling + insulation channel", which not only ensures the mechanical properties of H08Mn2E steel for submerged arc welding wire, but also ensures its drawing performance.

[0005] In order to achieve the above-mentioned purpose of the invention, the present invention provides a steel H08Mn2E for submerged arc welding wire, the chemical composition mass content of the steel for submerged arc welding wire is C: 0.05% ~ 0.10%, Si ≤ 0.07%, Mn: 1.50% ~ 1.90%, P ≤ 0.015%, S ≤ 0.010%, Ni: 0.35% ~ 0.45%, and the rest is Fe and other inevitable impurities.

[0006] The reasons for the composition design of the present invention are as follows:

[0007] C: The C content has a great influence on the strength, toughness, plasticity and structure of the weld, and should not be too high or too low. If the C content is too high, the toughness and plasticity of the weld will drop rapidly, and even cause the weld to crack. If the C content is too low, the weld strength will be affected. The C content is controlled at 0.05% to 0.10%.

[0008] Si: Adding a certain amount of Si can calm the weld metal, accelerate the deoxidation process of the molten pool metal, ensure the density of the weld, and also improve the strength of the weld; but excessive Si content is prone to form silicate inclusions and silicon cracks; the Si content is controlled to be ≤0.07%.

[0009] Mn: It is an effective element for strengthening and toughening welds. Mn can refine grains, improve low-temperature impact toughness of welds, and has deoxidation and desulfurization effects. At the same time, the addition of Mn ensures the strength lost due to the decrease in strength caused by carbon reduction; the Mn content is controlled at 1.50% to 1.90%.

[0010] P, S: P and S are harmful elements. Their contents are controlled to improve their purity, so they are required to reach a lower level; P≤0.015%, S≤0.010%.

[0011] Ni: helps to improve the toughness of the weld metal and reduce the ductile-brittle transition temperature; the Ni content is controlled at 0.35% to 0.45%.

[0012] Furthermore, the H08Mn2E steel wire rod for submerged arc welding wire has a tensile strength of 500-520 MPa, an elongation of 35%-40%, a cross-sectional reduction of 75%-80%, and non-metallic inclusions (A+C≤1.5; B+D≤1.5).

[0013] A method for preparing the above-mentioned steel H08Mn2E for submerged arc welding wire, the method comprising the following steps: converter smelting, LF refining, continuous casting, heating, rolling, and heat preservation channel;

[0014] ① Converter smelting: scrap steel accounts for 10% to 15%, molten iron accounts for 85% to 90%; 580 to 600 kg of nickel iron / furnace is added to the oxygen top and bottom double blowing converter together with scrap steel; the tapping temperature is 1680℃ to 1700℃, the tapping end point C is 0.04% to 0.055%, converter double slag smelting, the target one-time pouring P≤0.008%, and slag is strictly prohibited. The amount of auxiliary materials added per ton of steel: active lime 64 to 68 kg / t, dolomite 30 to 36 kg / t. Ladle alloying: lime, pre-deoxidizer and ferroalloy are added for deoxidation and alloying when 1 / 4 to 1 / 3 of the steel is tapped, and the argon blowing time is ≥5 minutes; the target amount of alloy added per ton of steel: metal manganese 15 to 17 kg / t, aluminum wire 1.3 to 1.5 m / t.

[0015] Static argon blowing: Static argon blowing time ≥ 8min, temperature before treatment 1600℃~1630℃, temperature after treatment 1590℃~1615℃, feeding pure calcium cored wire 1.0~1.2kg / t after static argon blowing, feeding wire speed 3m / s.

[0016] ②LF furnace refining: white slag operation is required. Under the condition of ensuring slag fluidity, the slag basicity and oxygen potential in the slag are controlled; the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements; the LF refining time is 60-80 minutes, and the full analysis temperature is 1580℃~1620℃. The amount of auxiliary materials added per ton of steel: active lime 8.2~8.4kg / t, fluorite 140~160kg / furnace, medium manganese 3.1~3.5kg / t, aluminum particles 1.2~1.6kg / t, aluminum wire 1.5~1.9m / t, calcium wire 1.4~1.8m / t, and the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements, and the soft blowing time is ≥12min.

[0017] ③Continuous casting: The crystallizer electromagnetic stirring current is 220-260A, the frequency is 4-6Hz, and the rotation is positive and negative; the terminal electromagnetic stirring current is 230-270A, the frequency is 4-8Hz, and the rotation is continuous. The platform temperature is 1605℃-1615℃, the tundish temperature is 1555℃-1575℃, the superheat is maintained at 25℃-35℃, and the casting speed is 2.2-2.4m / min. The whole process is protected casting, and the crystallizer protection slag uses the square billet low-carbon steel protection slag; the billet cutting adopts a combination of automatic and manual methods.

[0018] ④ Heating process: Use walking beam heating furnace for heating, preheating section 860℃~900℃, heating section 1080℃~1120℃, soaking section 1110℃~1150℃, heating time ≤2.5h.

[0019] ⑤Rolling process: rough rolling temperature 960℃~1000℃; finishing rolling inlet temperature 840℃~880℃; spinning temperature 880℃~920℃; the speed of the head roller of the air-cooled roller is 0.14~0.16m / s, and the speed increase of other sections of the roller is 0~5%.

[0020] ⑥ Insulation channel: The insulation channel maintains a temperature ≥ 60°C. The insulation channel is effectively utilized to ensure the effective release of tissue stress and internal stress, thereby ensuring the performance of the product and the performance requirements of the cleaning rod.

[0021] During the smelting process of the above-mentioned H08Mn2E steel for submerged arc welding wire, in order to make the Si content ≤0.07%, the actual operation adopts oxygen retention operation. At the same time, the Mn content is high (1.50%~1.90%) and the amount of alloy added is large, which increases the difficulty of subsequent dephosphorization and desulfurization; in order to ensure the purity of the molten steel in the later stage of the LF refining furnace, aluminum deoxidation is carried out; the ingot is subjected to the production mode of "controlled rolling and controlled cooling process + insulation channel slow cooling process", which can produce H08Mn2E steel for submerged arc welding wire that meets the requirements of low strength and high toughness.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention can effectively improve the quality of H08Mn2E wire rod for submerged arc welding wire. The low sulfur and phosphorus high manganese component design ensures the mechanical properties of the wire rod and the purity of the steel. An appropriate amount of Ni element is added to improve the toughness of the weld and ensure the quality of the weld. In the preparation method, the continuous casting adopts electromagnetic stirring of the crystallizer to improve the surface quality of the ingot and reduce internal cracks and center defects; the metallographic structure composed of ferrite and pearlite is obtained by the Stelmor controlled rolling and controlled cooling process combined with the slow cooling process; the mechanical properties of the H08Mn2E wire rod are guaranteed, and its drawing performance is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the microstructure diagram of steel H08Mn2E for submerged arc welding wire prepared in Example 1. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with specific examples, but the present invention is not limited in any way. To avoid redundant description, the raw materials in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0026] A steel H08Mn2E for submerged arc welding wire has the following chemical composition mass contents: C: 0.05%-0.10%, Si≤0.07%, Mn: 1.50%-1.90%, P≤0.015%, S≤0.010%, Ni: 0.35%-0.45%, and the rest is Fe and other inevitable impurities.

[0027] A method for preparing the above-mentioned steel H08Mn2E for submerged arc welding wire, the method comprising the following steps: converter smelting, LF refining, continuous casting, heating, rolling, and heat preservation channel;

[0028] ① Converter smelting: scrap steel accounts for 10% to 15%, molten iron accounts for 85% to 90%; ferronickel 580 to 600 kg / furnace is added together with scrap steel; static argon blowing time ≥ 8 min, temperature before treatment 1600℃ to 1630℃, temperature after treatment 1590℃ to 1615℃, pure calcium cored wire 1.0 to 1.2 kg / t is fed after static argon blowing, and wire feeding speed is 3 m / s;

[0029] ②LF refining: white slag operation, refining time 60-80min, full analysis temperature 1580℃~1620℃;

[0030] ③Continuous casting: crystallizer electromagnetic stirring current 220 ~ 260A, frequency 4 ~ 6Hz, forward and reverse; terminal electromagnetic stirring current 230 ~ 270A, frequency 4 ~ 8Hz, continuous rotation;

[0031] ④ Heating process: adopt walking beam heating furnace for heating, preheating section 860℃~900℃, heating section 1080℃~1120℃, soaking section 1110℃~1150℃, heating time ≤2.5h;

[0032] ⑤Rolling process: Rough rolling temperature 960℃~1000℃; Finishing rolling inlet temperature 840℃~880℃; Wire laying temperature 880℃~920℃;

[0033] ⑥Insulation channel: maintain temperature ≥60℃.

[0034] The matters not described in the following embodiments are the same as the description of the above specific implementation methods.

[0035] Example 1

[0036] A steel H08Mn2E for submerged arc welding wire, the main chemical components of the steel for submerged arc welding wire in Example 1 are shown in Table 1.

[0037] Table 1 Chemical composition of steel for submerged arc welding wire

[0038]

[0039]

[0040] Example 1 A method for preparing H08Mn2E steel for submerged arc welding wire comprises the following steps: converter smelting, LF refining, continuous casting, heating, rolling, and heat preservation channel;

[0041] ① Converter smelting: scrap steel accounts for 10%, molten iron accounts for 90%; 580kg / furnace of ferronickel is added to the converter with scrap steel and oxygen top and bottom blowing; tapping temperature is 1680℃, tapping end point C is 0.04%, converter double slag smelting, target one-time pouring P≤0.008%, slag is strictly prohibited. Amount of auxiliary materials added per ton of steel: 64kg / t of active lime, 31kg / t of dolomite. Ladle alloying: lime, pre-deoxidizer and ferroalloy are added for deoxidation and alloying when 1 / 4 to 1 / 3 of the steel is tapped, and the argon blowing time is 5min; target amount of alloy added per ton of steel: 15kg / t of metal manganese, 1.3m / t of aluminum wire.

[0042] Static argon blowing: static argon blowing time is 8 minutes, the temperature before treatment is 1600℃, the temperature after treatment is 1615℃, after static argon blowing, the pure calcium cored wire is fed at 1.0kg / t, and the wire feeding speed is 3m / s.

[0043] ②LF furnace refining: white slag operation is required. Under the condition of ensuring slag fluidity, the slag basicity and oxygen potential in the slag are controlled; the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements; LF refining time is 60 minutes, and the full analysis temperature is 1580℃. The amount of auxiliary materials added per ton of steel: active lime 8.2kg / t, fluorite 140kg / furnace, medium manganese 3.1kg / t, aluminum particles 1.2kg / t, aluminum wire 1.5m / t, calcium wire 1.4m / t, and the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements. The soft blowing time is 12 minutes.

[0044] ③Continuous casting: crystallizer electromagnetic stirring current 220A, frequency 4Hz, forward and reverse; terminal electromagnetic stirring current 230A, frequency 4Hz, continuous rotation. Platform temperature 1605℃, tundish temperature 1555℃, superheat maintained at 25℃, pulling speed 2.2m / min. Full process protection casting, crystallizer protective slag uses square billet low carbon steel protective slag; billet cutting adopts a combination of automatic and manual methods. The results of the low-magnification defect inspection of the billet in Example 1 are shown in Table 2.

[0045] Table 2 Results of macroscopic defects inspection of the ingots in the embodiment

[0046]

[0047] ④ Heating process: Use walking beam heating furnace for heating, preheating section 860℃, heating section 1080℃, soaking section 1110℃, heating time 2.5h.

[0048] ⑤Rolling process: rough rolling temperature 960℃, finishing rolling inlet temperature 840℃, spinning temperature 880℃, air-cooled roller speed: head roller speed 0.14m / s, other roller speed increase 5%; fan is fully closed, insulation cover is fully closed.

[0049] ⑥ Insulation channel: The insulation channel maintains a temperature of 60°C. The insulation channel is effectively utilized to ensure the effective release of tissue stress and internal stress, thereby also ensuring the performance of the product and the requirements of the performance difference of the cleaning rod.

[0050] Example 1 The mechanical properties of the steel H08Mn2E for submerged arc welding wire obtained by the above method are shown in Table 3. The tensile strength of the steel H08Mn2E for submerged arc welding wire is 510MPa, the elongation is 37%, and the cross-sectional shrinkage is 77%; the non-metallic inclusions A+C≤1.5, B+D≤1.5. The microstructure and non-metallic inclusions of the steel H08Mn2E for submerged arc welding wire obtained in Example 1 are shown in Table 4, and the metallographic structure diagram is shown in Figure 1 As shown, its metallographic structure is composed of ferrite (85-90%) + pearlite (10-15%), with ferrite accounting for a high proportion, and the wire rod has good plasticity and toughness.

[0051] Example 2

[0052] A steel H08Mn2E for submerged arc welding wire, the main chemical components of the steel for submerged arc welding wire in Example 2 are shown in Table 1.

[0053] Example 2 A method for preparing H08Mn2E steel for submerged arc welding wire comprises the following steps: converter smelting, LF refining, continuous casting, heating, rolling, and heat preservation channel;

[0054] ① Converter smelting: scrap steel accounts for 12%, molten iron accounts for 88%; 590kg / furnace of ferronickel is added to the converter with scrap steel and oxygen top and bottom blown; tapping temperature is 1690℃, tapping end point C is 0.045%, converter double slag smelting, target one-time pouring P≤0.008%, slag is strictly prohibited. Amount of auxiliary materials added per ton of steel: 65kg / t of active lime, 32kg / t of dolomite. Ladle alloying: lime, pre-deoxidizer and ferroalloy are added for deoxidation and alloying when 1 / 4 to 1 / 3 of the steel is tapped, and the argon blowing time is 6min; target amount of alloy added per ton of steel: 16kg / t of metal manganese, 1.4m / t of aluminum wire.

[0055] Static argon blowing: static argon blowing time is 9 minutes, the temperature before treatment is 1610℃, the temperature after treatment is 1600℃, and the pure calcium cored wire is fed at 1.1kg / t after static argon blowing, and the wire feeding speed is 3m / s.

[0056] ②LF furnace refining: white slag operation is required. Under the condition of ensuring slag fluidity, the slag basicity and oxygen potential in the slag are controlled; the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements; LF refining time is 65 minutes, and the full analysis temperature is 1590℃. The amount of auxiliary materials added per ton of steel: active lime 8.3kg / t, fluorite 150kg / furnace, medium manganese 3.2kg / t, aluminum particles 1.4kg / t, aluminum wire 1.6m / t, calcium wire 1.6m / t, and the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements. The soft blowing time is 14 minutes.

[0057] ③Continuous casting: crystallizer electromagnetic stirring current 240A, frequency 5Hz, forward and reverse; terminal electromagnetic stirring current 240A, frequency 5Hz, continuous rotation. Platform temperature 1610℃, tundish temperature 1560℃, superheat maintained at 28℃, pulling speed 2.3m / min. Full process protection casting, crystallizer protective slag uses square billet low carbon steel protective slag; billet cutting adopts a combination of automatic and manual methods. The results of the low-magnification defect inspection of the billet in Example 2 are shown in Table 2.

[0058] ④ Heating process: Use walking beam heating furnace for heating, preheating section 870℃, heating section 1090℃, soaking section 1120℃, heating time 2.3h.

[0059] ⑤Rolling process: rough rolling temperature 970℃, finishing rolling inlet temperature 850℃, spinning temperature 890℃, air-cooled roller speed: head roller speed 0.15m / s, other roller speed increase 3%; fan is fully closed, insulation cover is fully closed.

[0060] ⑥ Insulation channel: The insulation channel maintains a temperature of 70°C. The insulation channel is effectively utilized to ensure the effective release of tissue stress and internal stress, thereby ensuring the performance of the product and the requirements of the performance difference of the cleaning rod.

[0061] Example 2 The mechanical properties of the steel H08Mn2E for submerged arc welding wire obtained by the above method are shown in Table 3. The steel H08Mn2E for submerged arc welding wire has a tensile strength of 505MPa, an elongation of 40%, and a cross-sectional reduction of 77%; non-metallic inclusions A+C≤1.5, B+D≤1.5. The microstructure and non-metallic inclusions of the steel H08Mn2E for submerged arc welding wire obtained by Example 2 are shown in Table 4.

[0062] Example 3

[0063] A steel H08Mn2E for submerged arc welding wire, the main chemical components by mass content of the steel for submerged arc welding wire in Example 3 are shown in Table 1.

[0064] Example 3 A method for preparing H08Mn2E steel for submerged arc welding wire comprises the following steps: converter smelting, LF refining, continuous casting, heating, rolling, and heat preservation channel;

[0065] ① Converter smelting: scrap steel accounts for 13%, molten iron accounts for 87%; 585kg / furnace of ferronickel is added to the converter with scrap steel and oxygen top and bottom blown; tapping temperature is 1700℃, tapping end point C is 0.050%, converter double slag smelting, target one-time pouring P≤0.008%, slag is strictly prohibited. Amount of auxiliary materials added per ton of steel: 66kg / t of active lime, 33kg / t of dolomite. Ladle alloying: lime, pre-deoxidizer and ferroalloy are added for deoxidation and alloying when 1 / 4 to 1 / 3 of the steel is tapped, and the argon blowing time is 7min; target amount of alloy added per ton of steel: 17kg / t of metal manganese, 1.5m / t of aluminum wire.

[0066] Static argon blowing: static argon blowing time is 10min, temperature before treatment is 1620℃, temperature after treatment is 1610℃, pure calcium cored wire is fed at 1.2kg / t after static argon blowing, and wire feeding speed is 3m / s.

[0067] ②LF furnace refining: white slag operation is required. Under the condition of ensuring slag fluidity, the slag basicity and oxygen potential in the slag are controlled; the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements; LF refining time is 70 minutes, and the full analysis temperature is 1600℃. The amount of auxiliary materials added per ton of steel: active lime 8.4kg / t, fluorite 160kg / furnace, medium manganese 3.3kg / t, aluminum particles 1.5kg / t, aluminum wire 1.8m / t, calcium wire 1.7m / t, and the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements. The soft blowing time is 16 minutes.

[0068] ③Continuous casting: crystallizer electromagnetic stirring current 250A, frequency 6Hz, forward and reverse; terminal electromagnetic stirring current 260A, frequency 7Hz, continuous rotation. Platform temperature 1615℃, tundish temperature 1565℃, superheat maintained at 30℃, pulling speed 2.2m / min. Full process protection casting, crystallizer protective slag uses square billet low carbon steel protective slag; billet cutting adopts a combination of automatic and manual methods. The results of the low-magnification defect inspection of the billet in Example 3 are shown in Table 2.

[0069] ④ Heating process: Use walking beam heating furnace for heating, preheating section 880℃, heating section 1100℃, soaking section 1140℃, heating time 2.1h.

[0070] ⑤Rolling process: rough rolling temperature 990℃, finishing rolling inlet temperature 870℃, spinning temperature 910℃; air-cooled roller speed: head roller speed 0.14m / s, other roller speed increase 1%; fan is fully closed, insulation cover is fully closed.

[0071] ⑥ Insulation channel: The insulation channel maintains a temperature of 80°C. The insulation channel is effectively utilized to ensure the effective release of tissue stress and internal stress, thereby ensuring the performance of the product and the requirements of the performance difference of the cleaning rod.

[0072] Example 3 The mechanical properties of the steel H08Mn2E for submerged arc welding wire obtained by the above method are shown in Table 3. The steel H08Mn2E for submerged arc welding wire has a tensile strength of 508MPa, an elongation of 38%, and a cross-sectional reduction of 75%; non-metallic inclusions A+C≤1.5, B+D≤1.5. The microstructure and non-metallic inclusions of the steel H08Mn2E for submerged arc welding wire obtained in Example 3 are shown in Table 4.

[0073] Example 4

[0074] A steel H08Mn2E for submerged arc welding wire, the main chemical components by mass content of the steel for submerged arc welding wire in Example 4 are shown in Table 1.

[0075] Example 4 A method for preparing H08Mn2E steel for submerged arc welding wire comprises the following steps: converter smelting, LF refining, continuous casting, heating, rolling, and heat preservation channel;

[0076] ① Converter smelting: scrap steel accounts for 15%, molten iron accounts for 85%; 600kg / furnace of ferronickel is added to the converter with scrap steel for oxygen top and bottom blowing; tapping temperature is 1685℃, tapping end point C is 0.055%, converter double slag smelting, target one-time pouring P≤0.008%, slag is strictly prohibited. Amount of auxiliary materials added per ton of steel: 67kg / t of active lime, 34kg / t of dolomite. Ladle alloying: lime, pre-deoxidizer and ferroalloy are added for deoxidation and alloying when 1 / 4 to 1 / 3 of the steel is tapped, and the argon blowing time is 8min; target amount of alloy added per ton of steel: 16kg / t of metal manganese, 1.4m / t of aluminum wire.

[0077] Static argon blowing: static argon blowing time is 11min, temperature before treatment is 1630℃, temperature after treatment is ~1615℃, pure calcium cored wire is fed 1.0kg / t after static argon blowing, and wire feeding speed is 3m / s.

[0078] ②LF furnace refining: white slag operation is required. Under the condition of ensuring slag fluidity, the slag basicity and oxygen potential in the slag are controlled; the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements; LF refining time is 80 minutes, and the full analysis temperature is 1620℃. The amount of auxiliary materials added per ton of steel: active lime 8.3kg / t, fluorite 150kg / furnace, medium manganese 3.4kg / t, aluminum particles 1.6kg / t, aluminum wire 1.9m / t, calcium wire 1.8m / t, and the molten steel is constantly tested and the alloy is fine-tuned to ensure that the molten steel composition meets the standard requirements. The soft blowing time is 18 minutes.

[0079] ③Continuous casting: crystallizer electromagnetic stirring current 260A, frequency 5Hz, forward and reverse; terminal electromagnetic stirring current 270A, frequency 8Hz, continuous rotation. Platform temperature 1608℃, tundish temperature 1575℃, superheat maintained at 35℃, pulling speed 2.4m / min. Full process protection casting, crystallizer protective slag uses square billet low carbon steel protective slag; billet cutting adopts a combination of automatic and manual methods. The results of the low-magnification defect inspection of the billet in Example 4 are shown in Table 2.

[0080] ④ Heating process: Use walking beam heating furnace for heating, preheating section 900℃, heating section 1120℃, soaking section 1150℃, heating time ≤02.0h.

[0081] ⑤Rolling process: rough rolling temperature 1000℃, finishing rolling inlet temperature 880℃, spinning temperature 920℃; air-cooled roller speed: head roller 0.16m / s; fan is fully closed, and insulation cover is fully closed.

[0082] ⑥ Insulation channel: The insulation channel maintains a temperature of 90°C. The insulation channel is effectively utilized to ensure the effective release of tissue stress and internal stress, thereby ensuring the performance of the product and the requirements of the performance difference of the cleaning rod.

[0083] Example 4 The mechanical properties of the steel H08Mn2E for submerged arc welding wire obtained by the above method are shown in Table 3. The steel H08Mn2E for submerged arc welding wire has a tensile strength of 506 MPa, an elongation after fracture of 40%, and a cross-sectional reduction rate of 78%.

[0084] Table 3 Mechanical properties of steel H08Mn2E for submerged arc welding wire obtained in Example

[0085] Tensile strength / MPa Elongation after break / % Sectional shrinkage / % Example 1 510 37 77 Example 2 505 40 77 Example 3 508 38 75 Example 4 506 40 78

[0086] The microstructure and non-metallic inclusions of steel H08Mn2E for submerged arc welding wire obtained in Example 4 are shown in Table 4. The non-metallic inclusions A+C≤1.5 and B+D≤1.5.

[0087] Table 4 Microstructure and non-metallic inclusions of steel for submerged arc welding wire obtained in Example

[0088]

[0089] For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A steel H08Mn2E for submerged arc welding wire, characterized in that: The chemical composition mass content of the steel for submerged arc welding wire is C: 0.05%-0.10%, Si≤0.07%, Mn: 1.50%-1.90%, P≤0.015%, S≤0.010%, Ni: 0.35%-0.45%, and the rest is Fe and other inevitable impurities.

2. The steel H08Mn2E for submerged arc welding wire according to claim 1, characterized in that: The submerged arc welding wire steel H08Mn2E has a tensile strength of 500-520 MPa, an elongation of 35%-40%, and a cross-sectional shrinkage of 75%-80%; and non-metallic inclusions A+C≤1.5, and B+D≤1.

5.

3. A method for preparing the H08Mn2E steel for submerged arc welding wire as claimed in claim 1, characterized in that: The method comprises the following steps: converter smelting, LF refining, continuous casting, heating, rolling, and heat preservation channel; ① Converter smelting: scrap steel accounts for 10% to 15%, molten iron accounts for 85% to 90%; ferronickel 580 to 600 kg / furnace is added together with scrap steel; static argon blowing time ≥ 8 min, temperature before treatment 1600℃ to 1630℃, temperature after treatment 1590℃ to 1615℃, pure calcium cored wire 1.0 to 1.2 kg / t is fed after static argon blowing, and wire feeding speed is 3 m / s; ②LF refining: white slag operation, refining time 60-80min, full analysis temperature 1580℃~1620℃; ③Continuous casting: crystallizer electromagnetic stirring current 220 ~ 260A, frequency 4 ~ 6Hz, forward and reverse; terminal electromagnetic stirring current 230 ~ 270A, frequency 4 ~ 8Hz, continuous rotation; ④ Heating process: adopt walking beam heating furnace for heating, preheating section 860℃~900℃, heating section 1080℃~1120℃, soaking section 1110℃~1150℃, heating time ≤2.5h; ⑤Rolling process: Rough rolling temperature 960℃~1000℃; Finishing rolling inlet temperature 840℃~880℃; Wire laying temperature 880℃~920℃; ⑥Insulation channel: maintain temperature ≥60℃.

4. The preparation method according to claim 3, characterized in that: Step ① The tapping temperature of the converter smelting is 1680° C. to 1700° C., and the tapping end point C is 0.04% to 0.055%; double slag smelting, the target first pouring P is ≤0.008%.

5. The preparation method according to claim 3, characterized in that: In step ①, the amount of auxiliary materials added per ton of steel smelted in the converter is: 64-68 kg / t of active lime and 30-36 kg / t of dolomite; the amount of alloy added per ton of steel is: 15-17 kg / t of metallic manganese and 1.3-1.5 m / t of aluminum wire.

6. The preparation method according to claim 3, characterized in that: The amount of auxiliary materials added per ton of steel in the LF refining in step ② is: 8.2-8.4 kg / t of active lime, 140-160 kg / furnace of fluorite, 3.1-3.5 kg / t of medium manganese, 1.2-1.6 kg / t of aluminum particles, 1.5-1.9 m / t of aluminum wire, and 1.4-1.8 m / t of calcium wire.

7. The preparation method according to claim 3, characterized in that: In step ③, the platform temperature of the continuous casting is 1605°C to 1615°C, the tundish temperature is 1555°C to 1575°C, the superheat is maintained at 25°C to 35°C, and the pulling speed is 2.2 to 2.4 m / min.

8. The preparation method according to claim 3, characterized in that: In step ⑤, the speed of the air-cooled roller in the rolling process is 0.14-0.16 m / s for the head roller and 0-5% for the other rollers.

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