Hot-rolled wire rod for blasting lead and production method of hot-rolled wire rod

Abstract

The hot-rolled wire rod for the blasting lead comprises the following chemical components in percentage by mass: 0.03 to 0.06 percent of C, less than or equal to 0.030 percent of Si, 0.20 to 0.30 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S, less than or equal to 0.100 percent of Cr, less than or equal to 0.100 percent of Ni, less than or equal to 0.100 percent of Cu, less than or equal to 0.0070 percent of N and the balance of iron and other inevitable impurities. The invention further relates to a production method of the hot-rolled wire rod for the blasting lead, the production method comprises a smelting process and a rolling process, and the smelting process comprises the steps of KR desulfurization and slagging-off, converter smelting, LF refining and continuous casting. The steel wire rod for the blasting lead produced through the production method is good in mechanical property, the customer drawing machining process performance is excellent and stable, and the manufactured 0.55 mm blasting lead is good in resistivity and conductivity.

Description

Technical Field

[0001] The invention relates to the technical field of hot-rolled wire rod production, and in particular to a hot-rolled wire rod for blasting leads and a production method thereof. Background Art

[0002] BP05 blasting lead steel has strict requirements on the resistance stability of the final product, that is, the resistivity (resistance stability 0.54-0.58Ω / m). BP05 wire rod is drawn directly from φ5.5mm to φ1.9mm, and then drawn directly from 1.9mm to φ0.55mm after annealing. The internal quality requirements are strict. The main factors affecting the resistivity and drawing properties are chemical composition, uniformity of mechanical properties, microstructure and inclusions, so the above factors need to be strictly controlled.

[0003] According to the chemical composition, BP05 wire rod steel for blasting leads belongs to low carbon, low silicon and low manganese steel. It requires low carbon content at the end of converter smelting, high dissolved oxygen content in steel and large fluctuation. Generally, aluminum deoxidizer is used for final deoxidation, which is easy to cause blockage of nozzles and scarring on the surface of continuous casting billets. The reaction between steel slags in smelting production is easy to increase silicon in molten steel, and there is a possibility of excessive silicon content. Unsuitable refining slag system, short soft blowing time, and poor castability of molten steel causing continuous casting slag may all lead to high inclusion content in steel and poor drawing properties.

[0004] High content of harmful inclusions and gases in steel, unsuitable heating and rolling process during steel rolling, resulting in abnormal structure of wire rod due to overcooling, uneven grain size, poor performance of wire rod in the same circle, etc., may cause poor wire rod drawing performance. High content of inclusions and gases in wire rod, and uneven structure may lead to unqualified or unstable resistivity. Summary of the invention

[0005] The object of the present invention is to provide a hot rolled wire rod for blasting lead and a production method thereof, so as to solve the problem that the wire rod has high inclusion and gas content and uneven structure, which may lead to unqualified or unstable resistivity.

[0006] The technical solution adopted by the present invention is:

[0007] A hot-rolled wire rod for blasting lead, the chemical composition and mass percentage of the hot-rolled wire rod for blasting lead are: C: 0.03-0.06%, Si≤0.030%, Mn: 0.20-0.30%, P≤0.020%, S≤0.020%, Cr≤0.100%, Ni≤0.100%, Cu≤0.100%, N≤0.0070%, and the balance is iron and other inevitable impurities.

[0008] Preferably, it includes smelting and rolling processes, and the smelting process flow is: KR desulfurization and slagging - converter smelting - LF refining - continuous casting.

[0009] Preferably, KR desulfurization and slag skimming: all molten iron is subjected to KR desulfurization and slag skimming treatment, and the S content is ≤0.010wt%.

[0010] Preferably, converter smelting: control the ratio of molten iron into the furnace and the type of scrap steel, the mass ratio of molten iron into the furnace is ≥90%; top and bottom combined blowing converter bottom blowing Ar throughout the whole process, the number of supplementary blowing is ≤2 times, bottom blowing Ar before tapping at the converter end, stirring for 1-5min after zero position, adding lime to thicken the end slag before tapping, the amount of lime added is 300kg / furnace (average tapping amount is 125 tons / furnace, and the amount added per ton of steel is about 2.4kg / ton), the tapping port is rounded, the slag is strictly blocked during tapping, the ladle slag thickness is controlled to be ≤50mm, the end carbon is ≤0.050wt%, the end oxygen is 0.0500-0.1000wt%, P≤0.010wt%, S≤0.015wt%, aluminum manganese titanium iron is used for deoxidation, the oxygen of LF incoming steel liquid is ≤0.0100wt%, low carbon ferromanganese is used to match manganese, and the Mn lower limit of 0.20wt% is controlled (the manganese content expected by the dealer is controlled according to the lower limit).

[0011] Preferably, LF refining: controlling the refining cycle to 35-80min, LF refining uses cost-recovery steel or H08 steel casting residue, adding lime and fluorite to make gray-white slag with low reducibility (FeO%≤2wt%, SiO2≤10wt%, binary basicity R 2-5), using aluminum particles, SiC, calcined coal carburizer for diffusion deoxidation, using aluminum manganese titanium iron precipitation deoxidation, controlling the outlet oxygen ≤0.0030%, slagging and refining process, and outlet oxygen determination using an oxygen meter to ensure the deoxidation effect, seamless pure calcium line heavy calcium treatment, avoiding back and forth heating, controlling the heating time and the Ar flow rate of the ladle bottom blowing, and reducing the increase of silicon and nitrogen in the molten steel;

[0012] Use 0.16-0.24kg / ton of aluminum particles, 0.16-0.36kg / ton of silicon carbide SiC75, 0-0.12kg / ton of calcined coal recarburizer, diffusion deoxidation, use aluminum-manganese-titanium-iron precipitation deoxidation, aluminum-manganese-titanium-iron precipitation converter + LF refining usage 1.6-2.9kg / ton, control the refined slag FeO < 2.0wt%, SiO2 ≤ 10wt%, control the outlet oxygen ≤ 0.0030wt%, use an oxygen meter to determine the oxygen at the outlet of slag and refining process to ensure the deoxidation effect, seamless pure calcium line heavy calcium treatment, calcium line usage 0.4-1.0kg / ton, control the heating time within 25min and the ladle bottom blowing Ar flow 30-60L / min, soft blowing time ≥ 15min.

[0013] Preferably, during LF refining, the dust removal pressure is controlled while ensuring that no smoke is emitted, a slight positive pressure of the ladle furnace is ensured to be 20Pa-60Pa, low-carbon manganese is used to adjust manganese, and carbon cored wire is used to fine-tune carbon, the mass percentage of the components meets the requirements of C 0.03-0.05%, Si < 0.03%, Mn 0.20-0.25%, P ≤ 0.015%, S ≤ 0.020%, the first furnace temperature is 1615-1650°C, the continuous casting temperature is 1590-1635°C, seamless pure calcium iron wire is used for heavy calcium treatment, Ca / Al> 0.14, the ladle bottom blowing flow rate is controlled during the smelting process, the bottom blowing flow rate is controlled to be 20-200L / min, the wire feeding speed is 75-85m / min, and the soft blowing is performed for 15min before being hoisted to the continuous casting and pouring steel.

[0014] During LF refining, the dust removal pressure is controlled while ensuring that there is no smoke, the process atmosphere in the LF furnace is guaranteed, low-carbon manganese is used to adjust manganese, and carbon cored wire is used to fine-tune carbon. After the composition is qualified and the temperature is appropriate, seamless pure calcium iron wire is used for heavy calcium treatment (Ca / Al﹥0.14). During the smelting process, the ladle bottom blowing flow rate (the bottom blowing flow rate is controlled at 20-200L / min according to the purpose of the refining stage) and the wire feeding speed (about 80m / min) are properly controlled to avoid back and forth heating of the molten steel.

[0015] Preferably, the gray slag in LF refining includes lime and fluorite, and the gray slag has FeO≤2wt%, SiO2≤10wt%, and binary basicity R is 2-5.

[0016] Preferably, continuous casting: Ar seal for long water nozzle, argon blowing for tundish cover to protect pouring, and electromagnetic stirring of crystallizer; magnesium dry plug rod tundish for continuous casting, protection pouring throughout the pouring process, Ar seal for long water nozzle 130L / min, argon blowing for tundish cover, carbon-free low-silicon covering agent to cover tundish liquid level, H08 special protective slag to cover crystallizer steel liquid level, liquid level of tundish for steel casting not less than 500mm, casting section 165mm×165mm, constant pulling speed target 2.1-2.3m / min, automatic control of crystallizer liquid level, liquid level fluctuation control within ±3mm, crystallizer electromagnetic stirring 380A 3Hz, crystallizer water volume 158-171m 3 / h, the secondary cooling adopts the strong cooling mode.

[0017] Preferably, the rolling process is: heating - rolling - spinning - heat preservation cover - coiling - inspection - bundling - weighing and storage; higher starting rolling temperature, appropriate finishing rolling temperature and spinning temperature to ensure the generation of uniform coarse ferrite and a small amount of pearlite structure.

[0018] Preferably, the rolling process adopts heating furnace heating, the preheating section temperature is 880±50℃, the heating section temperature is 1100±50℃, the soaking section temperature is 1100±50℃, the start rolling temperature is 1000±20℃, the finishing rolling inlet is 930±20℃, the wire laying temperature is 910±20℃, the 2-10# insulation cover is closed, and the 2-10# insulation cover is closed after rolling.

[0019] Beneficial effects of the present invention:

[0020] During the smelting process, the silicon content of molten steel is small, the chemical composition is precisely controlled, the inclusion and gas content in the steel is low, the steel cleanliness is high, the wire rod metallographic structure is uniform and coarse, the performance of the wire rod in the same circle is stable, the wire rod can be drawn well, and the resistivity of the made blasting lead is stable and the conductivity is good.

[0021] All molten iron entering the furnace is subjected to KR desulfurization treatment, which reduces the burden of LF refining and desulfurization, shortens the refining and molten steel heating time, and reduces the silicon increase in molten steel.

[0022] The converter controls the iron liquid ratio to ≥90%, limits the amount of iron blocks used, and strictly prohibits the addition of iron blocks in the later stage of smelting to avoid uneven carbon content at the end.

[0023] Control the number of re-blowing to ≤2 times, adopt the 0 position and post-stirring technology before the converter tapping, promote the CO balance of steel slag, reduce the dissolved oxygen in molten steel, appropriately thicken the terminal slag before tapping, strictly block the slag during tapping, and minimize the slag under tapping, thereby reducing the inclusion content in the steel. Blow Ar at the bottom of the combined-blowing converter throughout the whole process, try to increase the hit rate of the endpoint once, reduce post-blowing, keep the tapping port round, blow Ar at the bottom of the tapping ladle, control the bottom blowing flow to avoid molten steel exposure, and control the nitrogen content of molten steel.

[0024] LF adopts slag return operation, and controls the refined final slag FeO < 2%, SiO2 content ≤ 10% before feeding the calcium line, improves the calcium line recovery rate, and reduces the silicon increase of slag reaction, controls the total heating time of the electrode ≤ 25min (avoiding the back and forth heating of the molten steel) and the bottom blowing flow of the ladle, avoids and reduces the silicon increase of the molten steel.

[0025] During the refining process, the arc slag covers the molten steel surface, controls the dust removal pressure of the refining furnace, ensures the process atmosphere in the LF furnace, controls the calcium feeding speed and the ladle bottom blowing flow rate, and reduces the nitrogen increase in the molten steel.

[0026] The binary basicity R of the refined slag is controlled to be 2-5, the mass content of Al2O3 and the mass content of SiO2 in the refined slag is controlled to be 25-35% and 5-10%, and the soft blowing time is ensured to be ≥15min to promote the full floating and removal of inclusions.

[0027] LF heavy calcium treatment ensures good castability of continuous casting molten steel.

[0028] Continuous casting uses sealing protection measures such as long water nozzle argon sealing, argon blowing on the middle ladle cover, covering agent, and protective slag covering the steel liquid surface to reduce nitrogen increase and secondary oxidation of molten steel. Strong cooling is used for the crystallizer and secondary cooling, and electromagnetic stirring of the crystallizer is used to improve the internal quality of the ingot.

[0029] Control the starting rolling temperature at a higher level to coarsen the austenite grains, control the appropriate finishing rolling temperature to avoid the appearance of bainite and martensite structures, control the wire drawing temperature at a higher level to allow the austenite to decompose at high temperature to generate coarse ferrite and a small amount of pearlite structure, and control the appropriate post-rolling air cooling process to make the wire rod grains uniform and the wire rod passability good.

[0030] The mechanical properties of the wire rod for blasting wire produced by the production method of the present invention are as follows: tensile strength Rm≤370MPa, elongation after fracture A≥35.0%, and cross-sectional shrinkage Z≥70%. The customer's drawing processing technology performance is excellent and stable, and the 0.55mm blasting wire produced has good resistivity and conductivity.

[0031] The wire rod for blasting fuse produced by the production method of the present invention has a tensile strength range of 311-354 MPa, an elongation after fracture of 40-52%, and a cross-sectional shrinkage of 73-81%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a plug rod pulling speed curve of Example 1 of the present invention.

[0033] Figure 2 This is the metallographic structure diagram of the wire rod according to Example 1 of the present invention.

[0034] Figure 3 This is a grain size diagram of the wire rod metallographic structure of Example 1 of the present invention.

[0035] Figure 4 This is a graph showing the thickness of the oxide scale of the wire rod in Example 1 of the present invention.

[0036] Figure 5 This is a diagram of inclusions in the wire rod according to Example 1 of the present invention.

[0037] Figure 6 This is a diagram of the size of inclusions in the wire rod according to Example 1 of the present invention. DETAILED DESCRIPTION

[0038] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0039] Example 1

[0040] KR desulfurization slag

[0041] The molten iron was subjected to KR desulfurization treatment, with the S content being 0.052% by mass before desulfurization and 0.005% by mass after desulfurization.

[0042] Converter smelting

[0043] The molten iron loading is 121.7 tons, scrap steel is 4 tons, the molten iron ratio into the furnace is 96.8%, high-quality scrap steel is used, and no iron blocks are used.

[0044] The top and bottom combined blowing converter is bottom blown with Ar throughout the whole process. The converter smelting end point mass content is: C0.052%, S0.007%, P0.008%, O:0.0444%, T1625℃. In order to avoid excessive carbon, supplementary blowing is performed twice (supplementary oxygen blowing 270m 3 ), end point carbon [C]: 0.031wt%, [O]: 0.0593wt%.

[0045] Before tapping, Ar was blown from the bottom of the converter at position 0 and stirred for 1 minute. The tapping amount was 117.5 tons. Slag was strictly blocked during tapping and the slag thickness in the ladle was controlled to be ≤50mm. 280kg of aluminum-manganese-titanium-iron was used for deoxidation. Low-carbon ferromanganese was used to match manganese, with an addition amount of 243kg. 300kg of lime was added to the tapping ladle.

[0046] LF Refining:

[0047] Refining cycle 45min, return H08 steel casting slag, add 204kg lime and 0kg fluorite to make slag, test the final slag composition Al2O332.06%, FeO 1.05%, CaO 47.9%, SiO2 9.76%, MgO 8.74%, MnO 0.85% binary basicity 4.9. Use 30kg aluminum particles, 20kg SiC75, 0kg calcined coal carburizer for diffusion deoxidation, use 40kg aluminum manganese titanium iron precipitation deoxidation, LF inlet oxygen meter oxygen determination 0.0052%, outlet oxygen determination 0.0013%, feed seamless pure calcium line 450m heavy calcium treatment, calcium feeding line speed 82m / min, molten steel Ca / Al 0.19. The refining process controls the heating time to be 12 minutes, the Ar flow rate of the ladle bottom blowing during the refining process is 80-200L / min, the ladle is hoisted to the continuous casting and pouring steel for 15 minutes, and the Ar flow rate of the ladle bottom blowing during the soft blowing process is 45L / min. The first furnace temperature is 1615℃, and the continuous casting temperature is 1590℃.

[0048] The ladle furnace of the LF refining process has a slight positive pressure of 40Pa-60Pa, and no low-carbon manganese 0kg and carbon cored wire are added. The outgoing composition of LF is C 0.037%, Si 0.014%, Mn 0.216%, P 0.008%, and S 0.006%.

[0049] Continuous Casting

[0050] The composition and mass percentage of the continuous casting tundish are C 0.04%, Si 0.014%, Mn 0.22%, P 0.008%, S 0.006%, Cr 0.015%, Ni 0.011%, Cu 0.009%, and N 0.0030%.

[0051] The continuous casting uses a magnesium dry plug rod tundish, and the pouring is protected throughout the pouring process (Ar seal 130L / min for the long water nozzle, argon blowing on the tundish cover, carbon-free low-silicon covering agent covering the tundish liquid level, H08 special protective slag covering the crystallizer steel liquid level). The normal pouring tundish liquid level shall not be lower than 500mm, the pouring section is 165mm×165mm, the tundish molten steel superheat is 31℃, the constant pulling speed is 2.1m / min, the crystallizer liquid level is automatically controlled, the liquid level fluctuation is controlled at ±3mm, the crystallizer electromagnetic stirring is 380A3Hz, and the crystallizer water volume is 158-171m 3 / h, the secondary cooling adopts the strong cooling mode.

[0052] Heating furnace heating and rolling

[0053] The temperature of the preheating section of the heating furnace is 920℃, the temperature of the heating section is 1127℃, the temperature of the soaking section is 1130℃, the rolling start temperature is 1011℃, the finishing rolling entrance is 930-940℃, the wire laying temperature is 910℃, and the air cooling insulation cover is fully opened after rolling.

[0054] Results and analysis:

[0055] (1) The continuous casting molten steel has good castability and the plug rod pulling speed curve is stable. Figure 1 .

[0056] (2) The surface quality of the continuous casting billet is good, without defects such as central shrinkage cavity, cracks, scars, pores, etc.

[0057] (3) The wire rod is cooled evenly, the appearance of the wire rod is blue, the performance of the wire rod is good, there is no obvious fluctuation in the tensile strength, and the iron sheet falls off in large pieces when stretched.

[0058] (4) The cross-section has a uniform structure at the edge, with some coarse grains in the center, with a grain size of 6.5-8.0. The grain size is 38-52 microns. Figure 2 and Figure 3 .

[0059] (5) The thickness of the iron oxide scale is about 45 microns, which is relatively thick overall. Figure 4 .

[0060] (6) The diameter of the inclusions detected in the steel is between 13-26 μm, and the rating is DS class 1.5, see Figure 5 and Figure 6 .

[0061] The mechanical properties of rolled Φ6.5mm wire rod, tensile strength, resistivity and conductivity are shown in Table 1:

[0062] Table 1

[0063]

[0064] Example 2

[0065] KR desulfurization slag

[0066] The molten iron was subjected to KR desulfurization treatment. The sulfur content of the molten iron before desulfurization was 0.061% and the sulfur content after KR desulfurization was 0.001%.

[0067] Converter smelting

[0068] The molten iron loading is 122 tons, scrap steel is 9.18 tons, the molten iron ratio is 93%, high-quality scrap steel is used, and no iron blocks are used.

[0069] The top and bottom combined blowing converter is bottom blown with Ar throughout the whole process. The final mass content of converter smelting is C0.027%, S0.006%, P0.008%, O:0.0889%, T1642℃. Before tapping, Ar is blown at the bottom of the converter at position 0 and stirring is performed for 5 minutes. The tapping amount is 124.5 tons. Slag is strictly blocked during tapping. The slag thickness of the ladle is controlled to be ≤50mm. 320kg of aluminum-manganese-titanium-iron is used for deoxidation. Low-carbon ferromanganese is used to match manganese, with an addition amount of 165kg. 300kg of lime is added to the tapping ladle.

[0070] The composition and mass percentage of the ladle after argon are C: 0.027%, Si: 0.010%, Mn: 0.15%, S: 0.0056%, P: 0.008%.

[0071] LF Refining

[0072] Refining cycle 43min, pouring residual slag of recovered steel, adding 98kg lime and 49kg fluorite to make slag, testing final slag composition Al2O326.81%, FeO 0.48%, CaO 52.13%, SiO2 10.4%, MgO 7.94%, MnO 0.25% binary basicity 5.0. Use 20kg aluminum particles, 40kg SiC75, 10kg calcined coal carburizer for diffusion deoxidation, use 48kg aluminum manganese titanium iron for precipitation deoxidation, LF inlet oxygen meter determines oxygen 0.0078%, outlet oxygen 0.0011%, feed seamless pure calcium line 400m heavy calcium treatment, calcium feeding line speed 85m / min, molten steel Ca / Al 0.20. The refining process controls the heating time to 8 minutes, the refining process ladle bottom blowing Ar flow rate 100-200L / min, soft blowing 15 minutes ladle hanging to continuous casting steel, soft blowing process ladle bottom blowing Ar flow rate 50L / min. The first furnace temperature is 1650℃, continuous casting temperature is 1635℃.

[0073] During the LF refining process, the ladle furnace has a slight positive pressure of 40Pa-50Pa, and 72kg of medium carbon manganese and 0kg of carbon cored wire are added. The outgoing composition of LF is C 0.0297%, Si 0.018%, Mn 0.216%, P 0.008%, and S 0.006%.

[0074] Continuous Casting

[0075] The composition and mass percentage of the molten steel in the continuous casting ladle are C: 0.030%, Si: 0.018%, Mn: 0.22%, S: 0.006%, P: 0.008%, Cr 0.012%, Ni 0.010%, Cu 0.008%, and N 0.0029%.

[0076] A magnesium dry material plug rod tundish is used, and the pouring is protected throughout the pouring process (Ar seal of the long water nozzle is 130L / min, argon is blown on the tundish cover, the carbon-free and low-silicon covering agent covers the tundish liquid level, and the H08 special protective slag covers the crystallizer steel liquid level). The liquid level of the tundish for normal steel pouring shall not be lower than 500mm, the pouring section is 165mm×165mm, the superheat of the molten steel in the tundish is 37℃, the constant pulling speed is 2.2m / min, the crystallizer liquid level is automatically controlled, the liquid level fluctuation is controlled at ±3mm, the crystallizer electromagnetic stirring is 380A3Hz, the crystallizer water volume is 158-171m3 / h, the secondary cooling adopts the strong cooling mode (1# water meter), the low shrinkage cavity of the ingot is 0-0.5 level, and the quality is good.

[0077] Heating furnace heating and rolling

[0078] The preheating section temperature of the heating furnace is 890-920℃, the heating section temperature is 1110-1130℃, the soaking section temperature is 1070-1092℃, the starting rolling temperature is 986-1012℃, the finishing rolling entrance temperature is 914-932℃, the wire laying temperature is 899-912℃, and the 2-10# insulation cover is closed after rolling.

[0079] The mechanical properties, resistivity and conductivity of rolled Φ6.5mm wire rod are shown in Table 2:

[0080] Table 2

[0081]

[0082] Example 3

[0083] KR desulfurization slag

[0084] The molten iron is subjected to KR desulfurization treatment, and the mass percentage of sulfur in the molten iron before desulfurization is 0.029%, and the mass percentage after KR desulfurization is 0.010%.

[0085] Converter smelting

[0086] The molten iron loading is 121 tons, scrap steel is 7.18 tons, and the molten iron ratio is 94.4%. High-quality scrap steel is used instead of iron blocks.

[0087] The top and bottom combined blowing converter was bottom blown with Ar throughout the whole process, with one re-blowing. The components and mass percentage of converter smelting end point were C0.047%, S 0.006%, P 0.007%, O:0.0537%, T1619℃, Ar was blown at the bottom of converter at position 0 and stirred for 2min before tapping. The tapping amount was 122.9 tons. Slag was strictly blocked during tapping, and the slag thickness of the ladle was controlled to be ≤50mm. 257kg of aluminum-manganese-titanium-iron was used for deoxidation, low-carbon ferromanganese was used to match manganese, and the addition amount was 220kg. 300kg of lime was added to the tapping ladle.

[0088] The composition and mass percentage of the ladle after argon are C: 0.027%, Si: 0.010%, Mn: 0.15%, S: 0.0056%, P: 0.008%.

[0089] LF Refining

[0090] Refining cycle 48min, pouring residual slag of return steel, adding 0kg lime and 0kg fluorite to make slag, and testing the final slag composition Al2O326.13%, FeO 0.38%, CaO 49.66%, SiO2 10.08%, MgO 7.84%, MnO 0.21%, binary basicity 4.9. Use 30kg aluminum particles, 30kg SiC75, 0kg calcined coal carburizer for diffusion deoxidation, use 20kg aluminum manganese titanium iron precipitation deoxidation, LF in station temperature measurement and oxygen determination 1576℃, O: 0.0007%. Out of the station temperature measurement and oxygen determination 1604℃, O: 0.0012%, feed seamless pure calcium line 350m heavy calcium treatment, calcium feeding line speed 83m / min, molten steel Ca / Al 0.18. The refining process controlled the heating time to be 11 minutes, the refining process ladle bottom blowing Ar flow rate was 100-200L / min, the soft blowing was 15 minutes and the ladle was hoisted to the continuous casting and pouring steel, and the soft blowing process ladle bottom blowing Ar flow rate was 35L / min. The first furnace temperature was 1635℃, and the continuous casting temperature was 1605℃.

[0091] During the LF refining process, the ladle furnace has a slight positive pressure of 40Pa-50Pa to ensure the process atmosphere in the LF furnace. Adding 0kg of medium carbon manganese and 0kg of carbon cored wire, the LF outgoing composition is C 0.053%, Si 0.018%, Mn 0.21%, P 0.007%, S 0.003%.

[0092] Continuous Casting

[0093] The composition and mass percentage of the molten steel in the continuous casting ladle are C: 0.05%, Si: 0.018%, Mn: 0.22%, S: 0.003%, P: 0.007%, Cr 0.010%, Ni 0.009%, Cu 0.008%, and N 0.0035%.

[0094] A magnesium dry material plug rod tundish is used, and the pouring is protected throughout the pouring process (Ar seal of the long water nozzle is 130L / min, argon is blown on the tundish cover, the carbon-free and low-silicon covering agent covers the tundish liquid level, and the H08 special protective slag covers the crystallizer steel liquid level). The liquid level of the tundish for normal steel pouring shall not be lower than 500mm, the pouring section is 165mm×165mm, the superheat of the molten steel in the tundish is 34℃, the constant pulling speed is 2.2m / min, the crystallizer liquid level is automatically controlled, the liquid level fluctuation is controlled at ±3mm, the crystallizer electromagnetic stirring is 380A3Hz, the crystallizer water volume is 160-170m3 / h, the secondary cooling adopts the strong cooling mode (1# water meter), the low shrinkage cavity of the ingot is 0-0.5 level, and the quality is good.

[0095] Heating furnace heating and rolling

[0096] The temperature of the preheating section of the heating furnace is 892-922℃, the temperature of the heating section is 1113-1134℃, the temperature of the soaking section is 1072-1096℃, the starting temperature is 988-1011℃, the finishing entrance is 917-931℃, the wire laying temperature is 900-914℃, and the 2-10# insulation cover is closed after rolling.

[0097] The mechanical properties of rolled Φ6.5mm wire rod, tensile strength, resistivity and conductivity are shown in Table 3:

[0098] Table 3

[0099]

[0100] Example 4

[0101] KR desulfurization slag

[0102] The molten iron is subjected to KR desulfurization treatment. The mass percentage of sulfur in the molten iron before desulfurization is 0.042%, and the mass percentage after KR desulfurization is 0.005%.

[0103] Converter smelting

[0104] The molten iron loading is 120 tons, scrap steel is 7.3 tons, and the molten iron ratio is 94.3%. High-quality scrap steel is used instead of iron blocks.

[0105] The top and bottom combined blowing converter was bottom blown with Ar throughout the whole process, with one re-blowing. The components and mass percentage of converter smelting end point were C0.034%, S 0.006%, P 0.007%, O:0.0678%, T1618℃. Ar was blown at the bottom of converter at position 0 and stirred for 2 minutes before tapping. The tapping amount was 123.6 tons. Slag was strictly blocked during tapping, and the slag thickness of the ladle was controlled to be ≤50mm. 267kg of aluminum-manganese-titanium-iron was used for deoxidation, low-carbon ferromanganese was used to match manganese, and the addition amount was 225kg. 300kg of lime was added to the tapping ladle.

[0106] The composition and mass percentage of the ladle after argon are C: 0.036%, Si: 0.022%, Mn: 0.19%, S: 0.0056%, P: 0.007%.

[0107] LF Refining

[0108] Refining cycle 58min, return the steel grade to pour the remaining slag, add 200kg lime, 50kg fluorite to make slag, the final slag composition is tested Al2O3 29.06%, FeO 0.38%, CaO 46.49%, SiO2, 10.45%, MgO 7.85%, MnO 0.21%

[0109] Binary basicity is 4.45. 20kg aluminum particles, 15kg SiC75, and 10kg calcined coal carburizer are used for diffusion deoxidation, and 30kg aluminum manganese titanium iron is used for precipitation deoxidation. The temperature of LF entering the station is 1566℃, O: 0.0013%. The temperature of the exit is 1595℃, O: 0.0028%, and the seamless pure calcium line is fed with 350m heavy calcium treatment, the calcium feeding line speed is 80m / min, and the molten steel Ca / Al is 0.17. The refining process controls the heating time to 13min, the refining process ladle bottom blowing Ar flow rate is 100-200L / min, the soft blowing 15min ladle is hoisted to the continuous casting and pouring steel, and the soft blowing process ladle bottom blowing Ar flow rate is 45L / min. The first furnace temperature is 1625℃, and the continuous casting temperature is 1625℃.

[0110] During the LF refining process, the ladle furnace has a slight positive pressure of 40Pa-60Pa to ensure the process atmosphere in the LF furnace. Add 60kg of medium carbon manganese and 0kg of carbon cored wire, and the LF outgoing composition is C 0.038%, Si 0.028%, Mn 0.23%, P 0.007%, S 0.003%.

[0111] Continuous Casting

[0112] The composition and mass percentage of the molten steel in the continuous casting ladle are C: 0.04%, Si: 0.03%, Mn: 0.23%, S: 0.003%, P: 0.007%, Cr 0.010%, Ni 0.007%, Cu 0.009%, and N 0.0037%.

[0113] A magnesium dry material plug rod tundish is used, and the pouring is protected throughout the pouring process (Ar seal of the long water nozzle is 130L / min, argon is blown on the tundish cover, the carbon-free and low-silicon covering agent covers the tundish liquid level, and the H08 special protective slag covers the crystallizer steel liquid level). The liquid level of the tundish for normal steel pouring shall not be lower than 500mm, the pouring section is 165mm×165mm, the superheat of the molten steel in the tundish is 34℃, the constant pulling speed is 2.2m / min, the crystallizer liquid level is automatically controlled, the liquid level fluctuation is controlled at ±3mm, the crystallizer electromagnetic stirring is 380A3Hz, the crystallizer water volume is 160-170m3 / h, the secondary cooling adopts the strong cooling mode (1# water meter), the low shrinkage cavity of the ingot is 0-0.5 level, and the quality is good.

[0114] Heating furnace heating and rolling

[0115] The temperature of the preheating section of the heating furnace is 891-925℃, the temperature of the heating section is 1114-1134℃, the temperature of the soaking section is 1076-1097℃, the starting rolling temperature is 989-1010℃, the finishing rolling entrance is 919-931℃, the wire laying temperature is 900-915℃, and the 2-10# insulation cover is closed after rolling.

[0116] The mechanical properties and tensile strength of rolled Φ6.5mm wire rod are shown in Table 4:

[0117] Table 4

[0118]

[0119] Example 5

[0120] KR desulfurization slag

[0121] The molten iron is subjected to KR desulfurization treatment. The mass percentage of sulfur in the molten iron before desulfurization is 0.049%, and the mass percentage after KR desulfurization is 0.007%.

[0122] Converter smelting

[0123] The molten iron loading is 119 tons, scrap steel is 7.3 tons, and the molten iron ratio is 94.2%. High-quality scrap steel is used instead of iron blocks.

[0124] The top and bottom combined blowing converter was bottom blown with Ar throughout the whole process, with 2 re-blowings. The final composition and mass percentage of converter smelting were C0.036%, S 0.008%, P 0.009%, O:0.0640%, T1620℃. Ar was blown at the bottom of converter at position 0 and stirred for 2 minutes before tapping. The tapping amount was 120.9 tons. Slag was strictly blocked during tapping, and the slag thickness of the ladle was controlled to be ≤50mm. 257kg of aluminum-manganese-titanium-iron was used for deoxidation, low-carbon ferromanganese was used to match manganese, with an addition amount of 210kg, and 300kg of lime was added to the tapping ladle.

[0125] The composition of the ladle after argon is C: 0.038%, Si: 0.012%, Mn: 0.19%, S: 0.007%, P: 0.009%.

[0126] LF Refining

[0127] Refining cycle 44min, pouring residual slag of recovered steel, adding 150kg lime and 50kg fluorite to make slag, testing the final slag composition Al2O3 27.69%, FeO 0.38%, CaO 48.4%, SiO2 10.86%, MgO 7.54%, MnO 0.31%, binary basicity 4.45. Use 30kg aluminum particles, 20kg SiC75, 0kg calcined coal carburizer for diffusion deoxidation, use 20kg aluminum manganese titanium iron for precipitation deoxidation, LF in-station temperature measurement and oxygen determination 1576℃, O: 0.0019%. Out-station temperature measurement and oxygen determination 1591℃, O: 0.0022%, feed seamless pure calcium line 350m heavy calcium treatment, calcium feeding line speed 83m / min, molten steel Ca / Al 0.16. The refining process controlled the heating time to be 11 minutes, the refining process ladle bottom blowing Ar flow rate was 100-200L / min, the soft blowing was 15 minutes and the ladle was hoisted to the continuous casting and pouring steel, and the soft blowing process ladle bottom blowing Ar flow rate was 45L / min. The first furnace temperature was 1645℃, and the continuous casting temperature was 1615℃.

[0128] During the LF refining process, the ladle furnace has a slight positive pressure of 40Pa-50Pa to ensure the process atmosphere in the LF furnace. Adding 16kg of medium carbon manganese and 0kg of carbon cored wire, the LF outgoing composition is C 0.041%, Si 0.018%, Mn 0.20%, P 0.009%, S 0.007%.

[0129] Continuous Casting

[0130] The composition and mass percentage of the molten steel in the continuous casting ladle are C: 0.04%, Si: 0.02%, Mn: 0.22%, S: 0.005%, P: 0.008%, Cr 0.010%, Ni 0.009%, Cu 0.008%, and N 0.0033%.

[0131] A magnesium dry material plug rod tundish is used, and the pouring is protected throughout the pouring process (Ar seal of the long water nozzle is 130L / min, argon is blown on the tundish cover, the carbon-free and low-silicon covering agent covers the tundish liquid level, and the H08 special protective slag covers the crystallizer steel liquid level). The liquid level of the tundish for normal steel pouring shall not be lower than 500mm, the pouring section is 165mm×165mm, the superheat of the molten steel in the tundish is 34℃, the constant pulling speed is 2.2m / min, the crystallizer liquid level is automatically controlled, the liquid level fluctuation is controlled at ±3mm, the crystallizer electromagnetic stirring is 380A3Hz, the crystallizer water volume is 160-170m3 / h, the secondary cooling adopts the strong cooling mode (1# water meter), the low shrinkage cavity of the ingot is 0-0.5 level, and the quality is good.

[0132] Heating furnace heating and rolling

[0133] The temperature of the preheating section of the heating furnace is 892-919℃, the temperature of the heating section is 1115-1134℃, the temperature of the soaking section is 1073-1097℃, the starting rolling temperature is 989-1011℃, the finishing rolling entrance is 918-930℃, the wire laying temperature is 902-914℃, and the 2-10# insulation cover is closed after rolling.

[0134] The mechanical properties of rolled Φ6.5mm wire rod, tensile strength, resistivity and conductivity are shown in Table 5:

[0135] Table 5

[0136]

[0137] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A hot rolled wire rod for blasting wire, characterized in that: The chemical composition and mass percentage of the hot-rolled wire rod for blasting fuse are: C: 0.03-0.06%, Si≤0.030%, Mn: 0.20-0.30%, P≤0.020%, S≤0.020%, Cr≤0.100%, Ni≤0.100%, Cu≤0.100%, N≤0.0070%, and the remainder is iron and other inevitable impurities.

2. The method for producing a hot-rolled wire rod for a blasting lead according to claim 1, characterized in that: Including smelting and rolling processes, the smelting process flow is: KR desulfurization slag - converter smelting - LF refining - continuous casting.

3. The method for producing hot-rolled wire rod for blasting lead according to claim 2, characterized in that: KR desulfurization and slag removal: All molten iron is subjected to KR desulfurization and slag removal treatment, and the S content is ≤0.010wt%.

4. The method for producing hot-rolled wire rod for blasting wire according to claim 2, characterized in that: Converter smelting: control the ratio of molten iron and the type of scrap steel entering the furnace, and the mass ratio of molten iron entering the furnace shall be ≥90%; Ar shall be blown from the bottom of the top and bottom combined blowing converter throughout the whole process, and the number of supplementary blowing shall be ≤2 times; Ar shall be blown from the bottom of the converter before tapping at the end of the converter, and stirring shall be carried out for 1-5 minutes after zeroing; lime shall be added to thicken the end slag before tapping, and the amount of lime added shall be 300kg / furnace; the tapping port shall be rounded, and slag shall be strictly blocked during tapping; the thickness of the ladle slag shall be controlled to be ≤50mm, the end carbon shall be ≤0.050wt%, the end oxygen shall be 0.0500-0.1000wt%, P≤0.010wt%, S≤0.015wt%, and aluminum-manganese-titanium-iron shall be used for deoxidation; the oxygen of molten steel entering the LF station shall be ≤0.0100wt%; low-carbon ferromanganese shall be used to match manganese, and the Mn lower limit of 0.20wt% shall be controlled.

5. The method for producing hot-rolled wire rod for blasting lead according to claim 2, characterized in that: LF refining: control the refining cycle to 35-80min, use the cost-recovery steel or H08 steel casting slag for LF refining, add lime and fluorite to make gray slag when entering the station, use 0.16-0.24kg / ton of aluminum particles, 0.16-0.36kg / ton of silicon carbide SiC75, 0-0.12kg / ton of calcined coal recarburizer, diffusion deoxidation, use aluminum-manganese-titanium-iron precipitation deoxidation, aluminum-manganese-titanium-iron precipitation converter + LF refining usage 1.6-2.9kg / ton, control the refining slag FeO <2.0wt%, SiO2 ≤10wt%, control the outlet oxygen ≤0.0030wt%, use an oxygen meter to determine the oxygen at the outlet of the slag and refining process to ensure the deoxidation effect, seamless pure calcium line heavy calcium treatment, calcium line dosage 0.4-1.0kg / ton, control the heating time within 25min and the ladle bottom blowing Ar flow 30-60L / min, soft blowing time ≥15min.

6. The method for producing hot-rolled wire rod for blasting lead according to claim 5, characterized in that: During LF refining, the dust removal pressure is controlled without smoke, and the ladle furnace is guaranteed to have a slight positive pressure of 20Pa-60Pa. Low-carbon manganese is used to adjust manganese, and carbon cored wire is used to fine-tune carbon. The mass percentage of the components meets the requirements of C 0.03-0.05%, Si<0.03%, Mn 0.20-0.25%, P≤0.015%, S≤0.020%. The first furnace temperature is 1615-1650℃, and the continuous casting temperature is 1590-1635℃. Seamless pure calcium iron wire is used for heavy calcium treatment, Ca / Al﹥0.

14. The bottom blowing flow of the ladle is controlled during the smelting process, and the bottom blowing flow is controlled at 20-200L / min and the wire feeding speed is 75-85m / min. Soft blowing is performed for 15min before hanging to the continuous casting and pouring steel.

7. The method for producing hot-rolled wire rod for blasting lead according to claim 5, characterized in that: The gray slag in LF refining includes lime and fluorite, and the gray slag has FeO≤2wt%, SiO2≤10wt%, and binary basicity R is 2-5.

8. The method for producing hot-rolled wire rod for blasting wire according to claim 2, characterized in that: Continuous casting: Ar seal for long shroud, argon blowing for tundish cover to protect pouring, and electromagnetic stirring for crystallizer; magnesium dry plug rod tundish is used for continuous casting, and the whole casting process is protected. Ar seal for long shroud is 130L / min, argon blowing for tundish cover, carbon-free low-silicon covering agent covers the tundish liquid level, H08 special protective slag covers the crystallizer steel liquid level, the tundish liquid level for steel casting is not less than 500mm, the casting section is 165mm×165mm, the constant pulling speed target is 2.1-2.3m / min, the crystallizer liquid level is automatically controlled, the liquid level fluctuation is controlled at ±3mm, the crystallizer electromagnetic stirring is 380A 3Hz, and the crystallizer water volume is 158-171m 3 / h, the secondary cooling adopts the strong cooling mode.

9. The method for producing hot-rolled wire rod for blasting lead according to claim 2, characterized in that: The rolling process is: heating - rolling - spinning - insulation cover - coiling - inspection - bundling - weighing and storage.

10. The method for producing hot-rolled wire rod for blasting wire according to claim 9, characterized in that: The rolling process adopts heating furnace heating, the preheating section temperature is 880±50℃, the heating section temperature is 1100±50℃, the soaking section temperature is 1100±50℃, the starting rolling temperature is 1000±20℃, the finishing rolling inlet is 930±20℃, the wire laying temperature is 910±20℃, and the 2-10# insulation cover is closed after rolling.

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