WO2015043057A1 - 一种非调质钢及其生产工艺 - Google Patents
一种非调质钢及其生产工艺 Download PDFInfo
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- WO2015043057A1 WO2015043057A1 PCT/CN2013/088377 CN2013088377W WO2015043057A1 WO 2015043057 A1 WO2015043057 A1 WO 2015043057A1 CN 2013088377 W CN2013088377 W CN 2013088377W WO 2015043057 A1 WO2015043057 A1 WO 2015043057A1
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/60—Aqueous agents
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
Definitions
- the invention relates to a non-quenched and tempered steel and a production process thereof, and belongs to the field of steel metallurgy technology.
- Non-quenched and tempered steel refers to mechanical structural steel that can meet the performance requirements without quenching and tempering.
- the use of such steel to manufacture parts can eliminate the quenching and tempering heat treatment process, which has the advantages of energy saving, materials and simple process, and can reduce the environment. Pollution, avoid oxidation, decarburization, deformation, cracking.
- Shougang Corporation has proposed a new non-quenched and tempered steel production process, which mainly includes: converter smelting, slag tapping, ladle deoxidation alloying, LF ladle refining, feeding S line, ladle bottom blowing argon to achieve The steps of full protection casting, temperature control of the casting blank, controlled cooling, and rolling, wherein, in the rolling step, the heating temperature is 1100 ⁇ 1180.
- the rolling temperature is 1020 ⁇ 1100.
- C finishing temperature 850 ⁇ 920.
- C the relative deformation is 15 ⁇ 35%, and is cooled to 600 after rolling. After C, slowly cool to room temperature.
- the non-quenched and tempered steel produced by the above process is difficult to ensure the core and surface of the steel in a short time by slow cooling.
- the temperature tends to be uniform, which tends to cause great fluctuations in the strength and toughness of the steel surface and the core, and the mechanical properties are severely uneven.
- the large-scale non-tempered steel is produced by the above process (for example, ⁇ 70 ⁇ ⁇ 145 ⁇ bar)
- the bar The phenomenon of uneven mechanical properties of the surface and the core of the bar is more pronounced.
- the technical problem to be solved by the present invention is to overcome the defects of surface mechanical properties and uneven core force performance of the steel produced by the existing non-quenched and tempered steel production process, thereby providing a non-quenched and tempered steel and a production process thereof. Ensure the surface mechanical properties of the finished product and the uniformity of the core mechanical properties.
- the present invention provides a non-quenched and tempered steel which is composed of the following chemical components: carbon 0.42 ⁇ 0.50, silicon 0.20 ⁇ 0.40, manganese 0.50 ⁇ 1.0, chromium 0.00 ⁇ 0.30, stroke 0.010 ⁇ 0.030, nickel 0.00 ⁇ 0.10, copper 0.00 ⁇ 0.20, brick 0.000 ⁇ 0.025, sulfur 0.00 ⁇ 0.025, and the balance is iron.
- the non-modulated steel of the present invention consists of the following chemical composition: carbon 0.42 ⁇ 0.45, silicon 0.20 ⁇ 0.30, sample 0.50 ⁇ 0.7, chromium 0.00 ⁇ 0.30 0.010 ⁇ 0.030, nickel 0.00 ⁇ 0.10, copper 0.00 ⁇ 0.20, brick 0.000 ⁇ 0.025, sulfur 0.00 ⁇ 0.025, and the balance is iron.
- the non-modulated steel of the present invention consists of the following chemical composition: carbon 0.42 ⁇ 0.47, silicon 0.25 ⁇ 0.35, manganese 0.60 ⁇ 1.0, chromium 0.00 ⁇ 0.30, aluminum 0.010 ⁇ 0.030, nickel 0.00 ⁇ 0.10, copper 0.00 ⁇ 0.20, brick 0.000 ⁇ 0.025, sulfur 0.00 ⁇ 0.025, and the balance is iron.
- the non-modulated steel of the present invention consists of the following chemical composition: carbon 0.45 ⁇ 0.50, silicon 0.25 ⁇ 0.35, manganese 0.60 - 0.9, chromium 0.00 - 0.30 0.010 ⁇ 0.030, nickel 0.00 ⁇ 0.10 , copper 0.00 ⁇ 0.20, brick 0.000 - 0.015, sulfur 0.00 - 0.015, and the balance is iron.
- the invention provides a production process of non-quenched and tempered steel, comprising a cooling step performed at least after the finishing rolling step, in which the alternating weak and weak cooling is used
- the steel is cooled by at least two stages of water penetration so that the core temperature of the steel tends to coincide with the surface temperature for a certain period of time.
- the steel material is subjected to three-stage water-passing cooling, wherein the first stage water-cooling is cooled by strong cooling, and the second stage is cooled by water. Weak cooling is used, and the third section is cooled by water.
- the strength of the cooling is controlled by controlling the degree of opening of the valve of the water-passing cooling device.
- the steel material is lowered by 100 in 4 to 7 seconds after being cooled by water.
- C ⁇ 400. C wait for the steel to return to temperature and then cool down again 50.
- the opening degree of the first stage valve is controlled to be 30% to 40%, and the opening degree of the second stage valve is 20%, and the third stage valve is opened.
- the degree is 30% ⁇ 40% to ensure that the steel surface temperature is lowered by 100 ° C - 400 in 4 ⁇ 7 seconds. C.
- the steel material is cooled and cooled by spray cooling after the steel material is warmed up.
- the steel material is dispersed and placed on a cold bed for air cooling for 10 to 12 minutes.
- the steel materials are stacked and then subjected to leather cooling.
- a finishing rolling step before the cooling step is also included, in which the temperature at which the steel material enters the finishing rolling step is controlled to be ⁇ 950. C, at a steel temperature of 850. C ⁇ 900. Low temperature rolling was carried out under C conditions.
- the smelting step before the finishing rolling step is further included, and the smelting step includes an electric furnace smelting step, a ladle furnace smelting step, and a refining step which are sequentially performed.
- the whole molten iron smelting is adopted in the electric furnace smelting, the end phosphorus content is ⁇ 0.015%, the end carbon content is 0.03% ⁇ 0.10%, and the end point temperature is 1620. C ⁇ 1700. C.
- silicon carbide and ferrosilicon powder are used for deoxidation in the ladle furnace smelting step and/or the refining step.
- the refining time is ensured to be not less than 45 minutes, and the hydrogen content is controlled to be less than 1.5 ppm.
- the production process of the non-quenched and tempered steel provided by the present invention further includes a continuous casting step after the refining step, in which the superheat degree is controlled at 20 to 35 ° C and the pulling speed is controlled at 0.5 m/ Min - 0.6m/ mm.
- the production process of the non-quenched and tempered steel provided by the present invention further includes a heating step after the continuous casting step, in which the slab is placed in a heating furnace for heating, wherein the temperature of the preheating section is controlled at 850 ⁇ 30 .
- the heating section temperature is controlled at 1100 ⁇ 30.
- the temperature of the soaking section is controlled at 1130 ⁇ 30°C, and the total time of the soaking section is not less than 2 hours.
- the present invention provides a process for the production of non-quenched and tempered steel, the process comprising the steps of:
- Electric furnace smelting step providing iron raw material with desired steel composition, using full iron smelting in the electric furnace smelting, the end phosphorus content is ⁇ 0.015%, the end carbon content is 0.03% ⁇ 0.10%, and the end temperature is 1620°C ⁇ 1700 ° C ;
- continuous casting step continuous casting of the steel melt obtained by the refining step, the superheat of the steel melt is controlled at 20 ⁇ 35 ° C, and the pulling speed is controlled at 0.5 m / min ⁇ 0.6 m / min;
- Heating step the slab produced by the continuous casting step is placed in a heating furnace for heating, wherein the temperature of the preheating section is controlled at 850 ⁇ 30. C, the heating section temperature is controlled at 1100 ⁇ 30°C, the soaking section temperature is controlled at 1130 ⁇ 30°C, and the soaking section total time is not less than 2 hours;
- Cooling step wherein the steel material is cooled by at least two stages of water passage in a manner of alternating strong and weak cooling so that the core temperature and the surface temperature tend to coincide during cooling.
- the production process of the non-quenched and tempered steel changes the manner of cooling before the finish rolling in the production of the non-tempered steel in the past, at least after the finishing rolling step, and the cooling method changes the prior art
- the use of a single water-cooled or air-cooled and consistent cooling method alternates between strong cooling and weak cooling. Strong cooling ensures that the surface temperature of the steel is rapidly reduced.
- the weak cooling allows the temperature of the core of the steel to gradually spread to the surface, followed by Strong cold, so that the heat is quickly dissipated, according to actual needs, strong cold and weak cold can be alternated several times, the combination of strong and weak cold water cooling method makes the temperature of the steel core and the temperature of the surface in a short time That is, it tends to be consistent, thereby ensuring the uniformity of the mechanical properties of the steel and improving the production efficiency.
- the steel material is subjected to three stages of water-passing cooling, wherein the first stage water-cooling is cooled by strong cooling, and the second section is cooled by water. Weak cooling is used, and the third section is cooled by water. After the finish rolling, the temperature of the steel is higher.
- the first stage is cooled by water
- the surface temperature of the steel is rapidly lowered. Due to the heat transfer, the heat of the core is gradually transferred to the surface after the surface temperature is lowered.
- a weak cooling method is adopted.
- the heat transfer causes the surface temperature to rise, and the surface is cooled again by the strong cooling method. Thereby, the surface heat is quickly taken away, and at this time, the heat transfer causes the surface temperature and the core temperature to converge, thereby ensuring uniformity of mechanical properties.
- the production process of the non-quenched and tempered steel provided by the present invention, in the cooling step, controlling the strength of the cooling by controlling the degree of opening of the valve of the water-passing cooling device, specifically, controlling the opening degree of the first stage valve to be 30% ⁇ 40%, the second valve opening is 20%, the third valve opening is 30% ⁇ 40%, to ensure that the steel surface temperature is reduced by 100 ° C ⁇ 400 ° C in 4 ⁇ 7 seconds, through Controlling the opening degree of the valve can control the water flow rate, and then control the strength of the water-through cooling.
- the control method is very simple. After the valve is opened for a certain length, the steel is penetrated into the water for water treatment, and the steel is in the process of water penetration. The surface is cooled in all directions to ensure uniformity of surface cooling.
- the production process of the non-quenched and tempered steel provided by the present invention, in the cooling step, after the steel material is returned to the temperature, the steel material is cooled and cooled by means of spray cooling.
- the way of spray cooling is a favorable supplement to water-cooling.
- spray cooling the heat of the core can be further diffused to the surface, which further ensures the consistency of the core and the surface temperature.
- the production process of the non-quenched and tempered steel provided by the present invention, after the cooling and cooling, the steel material is dispersed and placed on a cold bed for air cooling for 10 to 12 minutes. After the spray is cooled, the steel is dispersed and placed on a cold bed for air cooling, which can further supplement the spray cooling, so that the surface heat is further lost.
- the production process of the non-quenched and tempered steel provided by the present invention after the air cooling, the steel materials are stacked and then subjected to leather cooling.
- Leather cooling is a way of slow cooling.
- the steel is stacked and then subjected to leather cooling, after cooling by water cooling, spray cooling and air cooling.
- the surface temperature of the steel is basically consistent with the core temperature. At this time, the cooling rate is lowered by the method of leather cooling, which is beneficial to improve the microstructure of the steel.
- the production process of the non-quenched and tempered steel ensures that the refining time is not less than 45 minutes in the refining step, and the hydrogen content is controlled to be less than 1.5 ppm, and the refining process effectively controls the hydrogen content, which may be more Good to solve the risk of hydrogen cracking in the subsequent steel; more time to make the composition more uniform; give the inclusions more full floating time, effectively solve the problem of inclusion control, making the finished product more pure.
- the superheat degree is strictly controlled at 20 to 35 in the continuous casting step.
- the pulling speed is controlled from 0.5m/min to 0.6m/min.
- the low superheat and continuous drawing speed of continuous casting ensure the quality of the slab.
- the non-quenched and tempered steel provided by the invention has a metallographic structure of 500 times magnification as ferrite and pearlite, and the actual grain size (100 times) is rated as 10 to 11 according to GB/T6394, and the grain size is small.
- Uniform the difference from the core to the edge is not more than 1.5, the mechanical properties of the steel surface and the core are uniform, and the strength and toughness fluctuation from the core to the edge are small, which can effectively avoid the general processing of the surface after the surface processing amount is large.
- the mechanical properties do not meet the shortcomings of the use requirements.
- the difference in hardness from core to edge is less than 30HB, which can effectively avoid the adverse effects on the tool and processing when the hardness changes greatly, and the inclusion content is low and the purity is high.
- the core of the present invention is to improve the quality of the steel by substantially controlling the properties of the steel surface and the core by controlling the rolling and controlling the cooling step after rolling.
- Specific cooling controls include:
- the steel material is cooled by at least two stages of water passage in a manner of alternating strong and weak cooling, so that the core temperature of the steel material tends to coincide with the surface temperature in a specific time, specifically, after the finish rolling
- the steel material is cooled by three stages of water passage, wherein the first section of the water is cooled by strong cooling, the second section is cooled by water, and the third section is cooled by water, and the concrete is cooled by water.
- the degree of valve opening of the device controls the strength of the cooling.
- the strong cooling generally refers to cooling with a cooling rate of ⁇ 7 e C/S
- the weak cooling refers to cooling with a cooling rate of 2-4 ° C/s.
- the cooling control is performed by the above method (especially, water-cooling) to change the manner of cooling before the finish rolling in the production of the conventional non-quenched and tempered steel, at least after the finishing rolling step, and the cooling method is changed.
- a single water-cooling or air-cooling method with uniform strength is used to alternate between strong cooling and weak cooling, and strong cooling can ensure that the surface temperature of the steel is rapidly reduced, and the weak cooling can gradually spread the temperature of the steel core to the surface. Then, the strong cooling is carried out, so that the heat is quickly dissipated. According to the actual needs, the strong cooling and the weak cooling can be alternated several times.
- the combination of strong and weak cooling combined with the water cooling method makes the temperature of the steel core in a short time and The temperature of the surface tends to be uniform, thereby ensuring the uniformity of the mechanical properties of the steel and improving the production efficiency.
- the subsequent joint control of spray cooling, air cooling and leather cooling causes the core temperature to continuously scatter to the surface, and the surface temperature is continuously taken away, and the combination of the above cooling methods makes the cooling rate comparison. It is suitable to use leather cold after air cooling, so that the surface temperature of the steel is consistent with the core temperature, the cooling rate is not too fast, and the comprehensive mechanical properties are improved.
- FIG. 1 is a non-tempered steel produced by the production method of the present invention.
- Figure 2 is a photograph reflecting the grain size of a non-quenched and tempered steel produced by the production method of the present invention
- Fig. 3 is a view showing the condition of inclusions of non-heat treated steel produced by the production method of the present invention.
- the present embodiment provides a production method of non-quenched and tempered steel, which comprises a finish rolling step and a cooling step after finish rolling, wherein, in the finish rolling step, the temperature at which the rod is controlled to enter the finish rolling step is ⁇ 950. C, at bar temperature is 850. C ⁇ 900.
- the water flow rate is controlled by controlling the degree of opening of the valve of the water-passing cooling device, thereby controlling the cooling strength.
- the opening of the first section of the valve is 30% - 40%
- the opening of the second section is 20%
- the opening of the third section is 30% ⁇ 40%, which ensures that the surface temperature of the bar is reduced by 100 in 5 seconds.
- C ⁇ 400 °C after the bar is returned to temperature, the temperature of the bar is lowered by 50 °C ⁇ 100 °C by spray cooling, so that the heat is quickly dissipated, and then the bar is dispersed and placed on a cold bed. Cool in air-cooled mode for 10-12 minutes, and finally the bottom of the cooling bed will cool the bar.
- the production method of the non-quenched and tempered steel for direct cutting of the ordinary quenched and tempered 45 steel in this embodiment is such that the rod is cooled by three stages of water passage, wherein the first section is cooled by water and the second section is watered. The cooling is weakly cooled, and the third section is cooled by water. After the finish rolling, the bar temperature is higher, and the first section is cooled by water, so that the surface temperature of the bar is rapidly lowered. Due to the heat transfer, the core heat is gradually turned to the surface after the surface temperature is lowered.
- the present embodiment provides a method for producing non-quenched and tempered steel, which is a further improvement based on the embodiment 1, and further includes, in relation to the embodiment 1, a smelting step before the finishing rolling step, the smelting step
- the steps include an electric furnace smelting step, a ladle furnace smelting step, and a refining step.
- the electric furnace smelting step the whole iron smelting is adopted, the phosphorus content before tapping is strictly controlled ⁇ 0.015%, the end carbon content is 0.03% ⁇ 0.10%, and the end temperature is 1620°C - 1700°C.
- the electric furnace smelting can be more than the traditional converter smelting. Good control of slag operation.
- the ladle furnace (LF furnace) smelting step silicon carbide and ferrosilicon powder are used for deoxidation, and lime is added to make white slag.
- the white slag is kept for not less than 20 minutes, so that the white slag can completely remove inclusions.
- the refining furnace (VD furnace) smelting step degassing is performed to ensure that the hydrogen content is controlled below 1.5 ppm, and the refining time is not less than 45 minutes.
- the embodiment provides a method for producing non-quenched and tempered steel, which is a further improvement based on the embodiment 2.
- the continuous casting step and the heating step are improved, and the continuous casting step and the heating step are both located. After the refining step, it is before the rolling step and the water cooling step.
- the molten iron in the tundish is introduced into the crystallizer through the intrusive nozzle. It avoids the problem of easy introduction of air when introduced through the traditional nozzle.
- argon gas is blown at the joint of the immersion nozzle and the tundish to prevent air from entering the tundish.
- the superheat degree is strictly controlled at 20 ⁇ 35 °C, and the speed control is controlled. At 0.5m/min ⁇ 0.6m/min, the low superheat and continuous drawing speed of continuous casting ensure the quality of the slab.
- the temperature at which the cut is made during continuous casting is controlled to be ⁇ 820. C. After cutting, the surface of the slab should be inspected manually to ensure that there are no obvious defects.
- the slab is taken at a low magnification to ensure that the slab has no cracks, no shrinkage holes, and the center looseness is no more than 3 grades. This requirement is to ensure subsequent rolling out.
- the preheating section is 850 ⁇ 30°C and the heating section is 1100 ⁇ 30. C, the soaking section is 1130 ⁇ 30. C, to ensure that the total heating period is not less than 2 hours.
- This embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment, which is composed of the following chemical components: carbon 0.42, silicon 0.20, manganese 0.50, chromium 0.30, aluminum 0.010, nickel 0.10, Copper 0.20, phosphorus 0.010, sulfur 0.015, the balance is iron.
- This embodiment provides a non-quenched and tempered steel produced by the production method described in the above Embodiment 1, which is composed of the following chemical components: carbon 0.50, silicon 0.35, manganese 1.0, chromium 0.30, aluminum 0.030, nickel 0.10. , copper 0.20, phosphorus 0.015, sulfur 0.020, the balance is iron.
- Example 6
- This embodiment provides a non-quenched and tempered steel produced by the production method described in the above Embodiment 1, which is composed of the following chemical components: carbon 0.45, silicon 0.30, manganese 0.70, chromium 0.20, aluminum 0.020, nickel 0.05. , copper 0.10, phosphorus 0.010, sulfur 0.025, and the balance is iron.
- the present embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment 2, which is composed of the following chemical components: carbon 0.47, silicon 0.25, Manganese 0.60, chromium 0.30, aluminum 0.010, nickel 0.10, copper 0.20, phosphorus 0.010, sulfur 0.010, and the balance iron.
- the present embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment 2, which is composed of the following chemical components: carbon 0.48, silicon 0.28, manganese 0.8, chromium 0.30, aluminum 0.025, nickel 0.08 , copper 0.10, phosphorus 0.010, sulfur 0.015, and the balance is iron.
- the present embodiment provides a non-quenched and tempered steel produced by the production method described in the above Embodiment 2, which is composed of a chemical composition of the following weight percentage: carbon 0.43, silicon 0.30, manganese 0.55, chromium 0.25, aluminum 0.020, Nickel 0.10, copper 0.20, sulfur 0.012, and the balance is iron.
- Example 10 is composed of a chemical composition of the following weight percentage: carbon 0.43, silicon 0.30, manganese 0.55, chromium 0.25, aluminum 0.020, Nickel 0.10, copper 0.20, sulfur 0.012, and the balance is iron.
- This embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment 3, which is composed of the following chemical components: carbon 0.49, silicon 0.32, manganese 0.92, chromium 0.25, aluminum 0.018, nickel 0.20. , phosphorus 0.025, and the balance is iron.
- the present embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment 3, which is composed of the following chemical components: carbon 0.48, silicon 0.29, manganese 0.70, chromium 0.30, aluminum 0.028, nickel 0.15. , phosphorus 0.010, and the balance is iron.
- the present embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment 3, which is composed of a chemical composition having a weight percentage of carbon 0.50, silicon 0.40, manganese 1.0, chromium 0.30, and aluminum 0.018. Nickel 0.20, phosphorus 0.010, and the balance is iron.
- the present embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment 3, which is composed of the following chemical components: carbon 0.48, silicon 0.30, manganese 0.60, chromium 0.30, aluminum 0.015, phosphorus 0.010 , sulfur 0.010, and the balance is iron.
- Example 14 is composed of the following chemical components: carbon 0.48, silicon 0.30, manganese 0.60, chromium 0.30, aluminum 0.015, phosphorus 0.010 , sulfur 0.010, and the balance is iron.
- This embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment 3, which is composed of the following chemical components: carbon 0.49, silicon 0.28, manganese 0.75, aluminum 0.018, nickel 0.10, phosphorus 0.010. And the balance is iron.
- the present embodiment provides a non-quenched and tempered steel produced by the production method described in the above embodiment 3, which is composed of the following chemical components: carbon 0.47, silicon 0.28, manganese 0.75, aluminum 0.018, nickel 0.10, sulfur 0.010 , phosphorus 0.010, and the balance is iron.
- the metallographic structure of the non-quenched and tempered steel core of the above embodiments 4-15 is magnified and pearlite at 500 times (as shown in Fig. 1), and the actual grain size (100 times), according to GB/
- the T6394 has a rating of 10 to 11 (as shown in Figure 2).
- the grain is fine and uniform.
- the difference from the core to the edge is not more than 1.5.
- the mechanical properties of the steel surface and the core are uniform.
- the toughness fluctuation is very small, which can effectively avoid the shortcomings of the general material after the surface processing amount is large, the mechanical properties can not meet the requirements of use, and the hardness difference from the core to the edge is less than 30HB, which can effectively avoid the tool when the hardness changes greatly.
- the adverse effects of processing, and the inclusion content is low, the purity is high (as shown in Figure 3).
- the mechanical property data of the above Examples 4-15 are shown in Table 1 below.
- Table 1 the yield strength, tensile strength, elongation, and shrinkage ratio of the non-quenched and tempered steel produced by the production method provided by the present invention are shown.
- the comprehensive mechanical properties such as impact absorption work are excellent, and, as can be seen from the performance data in Table 1, the production method provided by the embodiment 3 of the present invention, and the chemical composition of the steel is carbon 0.50, silicon 0.35, manganese 1.0, Chromium 0.30, aluminum 0.018, nickel 0.20, phosphorus 0.010, balance iron, this example has the best overall mechanical properties, ie, the overall mechanical properties of Example 12 are the best.
- This embodiment provides a versatile non-quenched and tempered steel production method, which begins with a smelting step including an electric furnace smelting step, a ladle furnace smelting step, and a refining step.
- a smelting step including an electric furnace smelting step, a ladle furnace smelting step, and a refining step.
- the electric furnace smelting step the whole iron smelting is adopted, the phosphorus content before tapping is strictly controlled ⁇ 0.015%, the end carbon content is 0.03% ⁇ 0.10%, and the end temperature is 1620°C ⁇ 1700°C.
- the electric furnace smelting can be more than the traditional converter smelting. Good control of slag operation.
- the ladle furnace (LF furnace) smelting step silicon carbide and ferrosilicon powder are used for deoxidation, and lime is added to make white slag.
- the white slag is kept for not less than 20 minutes, so that the white slag can completely remove the inclusions.
- Smelting step in refining furnace VD furnace
- degassing is performed to ensure that the hydrogen content is controlled below 1.5 ppm, and the refining time is not less than 45 minutes.
- the continuous casting step is carried out after the refining step.
- the molten iron in the tundish is introduced into the crystallizer through the intrusive nozzle, which avoids the problem of easy introduction of air when introduced through the conventional nozzle, and argon gas is blown at the joint portion of the immersion nozzle and the tundish.
- the superheat is strictly controlled at 20 ⁇ 35 °C, and the pulling speed is controlled at 0.5m/min ⁇ 0.6m/min.
- the low superheat and continuous drawing speed of continuous casting ensure the quality of the casting blank.
- the temperature at which the cut is made during continuous casting is controlled to be ⁇ 820.
- the preheating section is 850 ⁇ 30.
- the soaking section is 1130 ⁇ 30 °C, and the total time of the soaking section is not less than 2 hours.
- a finishing rolling step and a cooling step are performed after the heating step; in the finishing rolling step, the temperature at which the rod is controlled to enter the finishing rolling step is ⁇ 950.
- C, at bar temperature is 850.
- the water flow rate is controlled by controlling the degree of opening of the valve of the water-passing cooling device, thereby controlling the cooling strength.
- the opening degree of the first-stage valve is 30% to 40%
- the second stage The valve opening is 20%
- the third valve opening is 30% ⁇ 40%, which can reduce the surface temperature of the bar by 100% within 5s.
- C ⁇ 400 °C after the bar is returned to temperature, the temperature of the bar is lowered by 50 °C ⁇ 100 °C by spray cooling. The heat is quickly dissipated, and then the bar is dispersed and placed on a cold bed to be cooled by air cooling for 10-12 minutes, and finally the lower bed is cooled by stacking the bar.
- the rod is subjected to three-stage water-cooling, wherein the first stage of water-cooling adopts strong cooling, the second stage of water-cooling adopts weak cooling, and the third section adopts water-cooling. Strong cold.
- the bar temperature is higher, and the first section is cooled by water, so that the surface temperature of the bar is rapidly lowered. Due to the heat transfer, the core heat is gradually turned to the surface after the surface temperature is lowered.
- the weak cooling method in order to transfer the heat of the core to the surface as much as possible, the weak cooling method is adopted in the second stage of water-cooling, so that more time is reserved for heat transfer to the core during the cooling process, after weak cooling, The heat transfer causes the surface temperature to rise, and the surface is quickly cooled by the strong cooling method, so that the surface heat is quickly taken away. At this time, the heat transfer causes the surface temperature and the core temperature to converge, thereby ensuring the mechanical properties. Uniformity.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
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Abstract
Description
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EP13894743.7A EP3050991A4 (en) | 2013-09-26 | 2013-12-03 | Non-quenched and tempered steel and manufacturing method therefor |
US15/023,513 US20160208356A1 (en) | 2013-09-26 | 2013-12-03 | Non quenched and tempered steel and manufacturing process thereof |
JP2016516510A JP2017502165A (ja) | 2013-09-26 | 2013-12-03 | 非調質鋼及びその製造方法 |
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EP (1) | EP3050991A4 (zh) |
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CN113145817A (zh) * | 2020-12-24 | 2021-07-23 | 山东寿光巨能特钢有限公司 | 一种控制含锰钢大圆坯表面微裂纹的方法 |
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CN105855299B (zh) * | 2014-12-22 | 2019-03-15 | 苏州苏信特钢有限公司 | 一种钢的轧制方法及使用该方法获得的钢 |
CN105568134A (zh) * | 2016-01-05 | 2016-05-11 | 江阴兴澄特种钢铁有限公司 | 一种微合金化轿车碳素轮毂轴承用钢及其制造方法 |
CN110964975B (zh) * | 2018-09-28 | 2021-10-26 | 苏州苏信特钢有限公司 | 一种非调质钢及其制备方法和注塑机用拉杆 |
CN111618264B (zh) * | 2020-06-02 | 2021-08-20 | 北京科技大学 | 一种提高铸坯温度均匀性的铸坯冷却方法 |
CN111549287B (zh) * | 2020-06-28 | 2021-08-03 | 宝钢特钢韶关有限公司 | 中碳钢及其生产工艺 |
CN113634594B (zh) * | 2021-07-09 | 2023-03-21 | 包头钢铁(集团)有限责任公司 | 一种汽车车桥管用热轧圆钢的制备方法 |
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JP2017502165A (ja) | 2017-01-19 |
US20160208356A1 (en) | 2016-07-21 |
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