WO2015043061A1 - 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 PDF

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Publication number
WO2015043061A1
WO2015043061A1 PCT/CN2013/088383 CN2013088383W WO2015043061A1 WO 2015043061 A1 WO2015043061 A1 WO 2015043061A1 CN 2013088383 W CN2013088383 W CN 2013088383W WO 2015043061 A1 WO2015043061 A1 WO 2015043061A1
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Prior art keywords
cooling
quenched
temperature
steel
tempered steel
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PCT/CN2013/088383
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English (en)
French (fr)
Inventor
刘栋林
周旭
徐益峰
周志伟
俞杰
Original Assignee
北大方正集团有限公司
苏州苏信特钢有限公司
江苏苏钢集团有限公司
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Application filed by 北大方正集团有限公司, 苏州苏信特钢有限公司, 江苏苏钢集团有限公司 filed Critical 北大方正集团有限公司
Priority to EP13894442.6A priority Critical patent/EP3050994A4/en
Priority to US15/023,544 priority patent/US20160230247A1/en
Priority to JP2016516505A priority patent/JP2016540881A/ja
Publication of WO2015043061A1 publication Critical patent/WO2015043061A1/zh

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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
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
    • 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
    • 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
    • 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
    • C21D1/62—Quenching devices
    • C21D1/667—Quenching devices for spray quenching
    • 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
    • C21D11/00—Process control or regulation for heat treatments
    • C21D11/005—Process control or regulation for heat treatments for cooling
    • 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
    • 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
    • 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
    • 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
    • C21D8/0231—Warm rolling
    • 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
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
    • 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
    • C21D9/0062—Heat-treating apparatus with a cooling or quenching zone
    • 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
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
    • B21B37/76—Cooling control on the run-out table
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite

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-tempered steel refers to mechanical structural steel that can meet performance requirements without quenching and tempering.
  • the use of such steel to manufacture parts can eliminate the quenching and tempering heat treatment process, and has the advantages of energy saving, materials, and simple process, which can reduce the environment. Pollution, avoid oxidation, decarburization, deformation, cracking.
  • non-tempering non-tempered steel The traditional domestic production of non-tempering non-tempered steel is: electric furnace smelting ⁇ refining ⁇ mold casting ⁇ controlled rolling and cooling.
  • the difficulty of this process in production is: Control of steel properties.
  • most domestic and foreign manufacturers have improved the chemical properties of non-tempered steel to achieve the control of steel properties.
  • studies have shown that it is difficult to achieve non-tempering steel performance requirements simply by component design.
  • 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 Full protection casting, slab temperature control, controlled cooling and rolling steps, wherein in the rolling step, the heating temperature is 1100 ⁇ 1180 ° C, the rolling temperature is 1020 ⁇ 1100 °C, and the finishing temperature is 850 ⁇ 920 °C The relative deformation is 15 ⁇ 35%. After rolling, it is cooled to 600 °C and then slowly cooled to room temperature.
  • Non-tempered steel produced by the above process The slow cooling method is difficult to ensure that the temperature of the core and the surface of the steel tends to be uniform in a short period of time. It is easy to cause the strength and toughness of the steel surface and the core to fluctuate greatly, and the mechanical properties are seriously uneven.
  • quenching and tempering steel for example, ⁇ 70 ⁇ (pl45mm bar)
  • the phenomenon of uneven mechanical properties of the bar surface and the core of the bar is more obvious.
  • the technical problem to be solved by the present invention is to overcome the defects of surface mechanical properties and core force performance unevenness 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 0.35 to 0.47, shoes 0.30 to 0.60, manganese 1.20 to 1.60, chromium 0.00 to 0.30, aluminum 0.010 to 0.030, nickel 0.00. ⁇ 0.10, copper 0.00 ⁇ 0.20, phosphorus 0.000 ⁇ 0.020, sulfur 0.020 ⁇ 0.020, vanadium 0.050 ⁇ 0.250, nitrogen 0.012 ⁇ 0.020, and the balance is iron.
  • the non-modulated steel of the present invention consists of the following chemical composition: carbon 0.45 ⁇ 0.47, silicon 0.30 ⁇ 0.50, manganese 1.30 ⁇ 1.60, chromium 0.00 ⁇ 0.20, aluminum 0.010 ⁇ 0.020, nickel 0.00 ⁇ 0.08 , copper 0.00 ⁇ 0.10, monument 0.000 ⁇ 0.010, sulfur 0.00 ⁇ 0.010, vanadium 0.050 ⁇ 0.250, nitrogen 0.012 ⁇ 0.020, 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 steel material is cooled by at least two stages of water cooling by alternating strong and weak cooling. So that the core temperature of the steel tends to coincide with the surface temperature for a certain period of time.
  • the steel material in the production process of the non-quenched and tempered steel provided by the present invention, in the cooling step, the steel material is cooled by three stages of water passage, wherein the first stage of water cooling is strongly cooled, and the second stage is water cooled. 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 cooling step after the steel material is cooled by water penetration, it is lowered by 100 ° C to 400 ° C in 4 to 7 seconds, after the steel is returned to the temperature. Cool down again from 50 °C to 100 °C.
  • 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 ° C in 4 ⁇ 7 seconds.
  • 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 a cover cooling.
  • the production process of the non-quenched and tempered steel provided by the present invention further includes a finishing rolling step before the cooling step, in which the temperature of the steel material entering the finishing rolling step is controlled to be ⁇ 850° ⁇ , at the steel temperature Low temperature rolling at 850 ° C ⁇ 900 ° C.
  • the production process of the non-quenched and tempered steel provided by the present invention further includes a smelting step before the finishing rolling step, 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 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 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 step In the production process of the non-quenched and tempered steel provided by the present invention, in the ladle furnace smelting step, white slag is formed, and the white slag is maintained for not less than 20 minutes. In the production process of the non-quenched and tempered steel provided by the present invention, in 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.
  • a continuous casting step after the refining step is further included, 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/min.
  • 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 °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.
  • the invention provides a production process of non-quenched and tempered steel, which process comprises the following steps in sequence:
  • Electric furnace smelting step providing molten 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 ;
  • heating step wherein the slab generated 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., and the temperature of the heating section is controlled at 1100 ⁇ 30° C., the soaking section The temperature is controlled at 1130 ⁇ 30°C, and the total time of the soaking section is not less than 2 hours;
  • finishing rolling step wherein the temperature at which the steel material enters the finishing rolling step is ⁇ 850 ° C, and the low temperature rolling is performed at a steel temperature of 850 ° C to 900 ° C;
  • 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 of the steel material and the surface temperature tend to coincide during cooling and 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 is changed in the prior art.
  • the cooling method with single water cooling or air cooling and strong consistency is used to alternate between strong cooling and weak cooling. Strong cooling can ensure the surface temperature of the steel is rapidly reduced.
  • the weak cooling can gradually spread the temperature of the core of the steel to the surface, and then strengthen it.
  • the combination of strong and weak cold water cooling method makes the temperature of the steel core and the surface temperature in a short time Convergence ensures uniformity of mechanical properties of the steel and increases production efficiency.
  • the steel material is subjected to three-stage water-cooling, wherein the first stage of 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 The opening degree of the segment valve is 30% ⁇ 40%, to ensure that the surface temperature of the steel is lowered by 100 ° C ⁇ 400 ° C in 4 ⁇ 7 seconds.
  • the opening degree of the valve the water flow can be controlled, thereby controlling the strong water penetration cooling.
  • the degree of weakness is very simple. After the valve is opened for a certain length, the steel is penetrated into the water for water treatment. When the steel is in the process of water penetration, the surface is cooled in all directions, ensuring 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 method of spray cooling is a favorable supplement for water-cooling.
  • the spray cooling can further diffuse the heat of the core to the surface, which 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 - 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, stacking the steel materials and performing cover cooling.
  • Cover cold is a way of slow cooling.
  • the steel is stacked and then cold-sealed, and cooled by water-cooling, spray cooling and air cooling. After the method, the surface temperature of the steel has reached the same level as the core temperature. At this time, the cooling rate is lowered by the cover cooling method, 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 and the hydrogen content is controlled to be less than 1.5 ppm in the refining step, and the refining process effectively controls the hydrogen content, which may be more Good solution to the risk of hydrogen cracking in subsequent steels; More time is available to make the ingredients more uniform; Give the inclusions more full floating time, effectively solve the problem of inclusion control, and make the finished product more pure.
  • the superheat degree is strictly controlled at 20 ⁇ 35 ° C
  • the pulling speed is controlled at 0.5 m / min ⁇ 0.6 m / min
  • the low superheat of continuous casting ensures the quality of the slab.
  • the non-quenched and tempered steel produced by the production process provided by the invention has a metallographic structure of 500 times and a ferrite and pearlite, and the actual grain size (100 times) is rated as 10 to 11 according to GB/T6394.
  • the grain is fine and uniform, and 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 strength and toughness fluctuation from the core to the edge are small, which can effectively avoid the surface processing of general materials. After the larger, the mechanical properties can not meet the shortcomings of the use requirements.
  • the difference from the core to the edge hardness is less than 30HB, which can effectively avoid the adverse effects on the tool and the processing when the hardness changes greatly, and the inclusion content is low and the purity is better. 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 certain time, specifically, after finish rolling
  • the steel material is cooled by three stages of water passage, wherein the first section is cooled by water and cooled by strong cold, the second section is cooled by water, and the third section is cooled by water, and the concrete is cooled by water.
  • the intensity of the cooling is controlled by controlling the degree of opening of the valve through the water cooling device.
  • the strong cooling generally means cooling with a cooling rate of ⁇ 7 ° C / S; and the weak cooling means cooling with a cooling rate of 2-4 O / S.
  • the cooling control is performed by the above method (especially, water-cooling), and the manner of cooling before the finish rolling in the production of the conventional non-quenched and tempered steel is changed, at least the cooling step is set 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 alternately performed multiple times.
  • the combination of strong and weak cold water cooling means the temperature of the steel core in a short time.
  • 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 hood 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.
  • the cover is cooled, 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.
  • Figure 1 is a metallographic picture of a non-quenched and tempered steel produced by the production method of the present invention at a magnification of 500 times;
  • 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 inclusion of non-tempered steel produced by the production method of the present invention.
  • the embodiment provides a method for producing non-quenched and tempered steel, comprising a finishing rolling step and a cooling step after finishing rolling, wherein in the finishing rolling step, the temperature at which the control bar enters the finishing rolling step is ⁇ 850° ⁇ , low-temperature rolling at a bar temperature of 850 °C ⁇ 900 °C; after rolling, the steel is subjected to three-stage water-cooling through a professionally controllable water-cooling equipment. Cold, the second stage of water cooling uses weak cooling, and the third stage of water cooling uses strong cooling.
  • 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 first section of the valve opening is 30% ⁇ 40%
  • the second section of the valve opening is 20%
  • the third section of the valve opening is 30% ⁇ 40%, to ensure that the bar surface temperature is reduced by 150 ° within 5s C ⁇ 400 °C, after the bar is returned to temperature, the bar is cooled by 50 °C ⁇ 100 °C by spray cooling, so that the heat is quickly dissipated, then the bar is dispersed and placed on a cold bed with air cooling. The method is cooled for 10-12 minutes, and finally the lower cooling bed will cool the bar stacking cover.
  • the production method of the non-quenched and tempered steel of the embodiment is such that the rod is cooled by three stages of water-passing, wherein the first section of the water is cooled by strong cooling, the second section is cooled by water, and the third section is watered. Cool and use strong cold. 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 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. Example 2
  • 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 whole iron smelting is adopted, and the phosphorus content before tapping is strictly controlled.
  • the end carbon content is 0.03% ⁇ 0.10%
  • the end temperature is 1670 °C ⁇ 1700 °C.
  • the electric furnace smelting can better control the slag operation than the traditional converter smelting.
  • 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.
  • degassing is carried out to ensure that the hydrogen content is controlled below 1.5 ppm, and the refining time is not less than 45 minutes.
  • the present embodiment provides a method for producing non-quenched and tempered steel, which is a further improvement based on the embodiment 1 or 2.
  • the continuous casting step and the heating step are improved, the continuous casting step and the heating step Both are located after the refining step and before the rolling step and the water-cooling step.
  • the molten iron in the tundish is introduced into the crystallizer through the intrusive nozzle, thereby avoiding the problem of easy introduction of air when introduced through the conventional nozzle, and argon gas is blown at the joint of the immersion nozzle and the tundish to avoid Air enters the tundish, the superheat is strictly controlled at 23 ⁇ 35 °C, the pulling speed is controlled at 0.5m/min ⁇ 0.6m / min, continuous casting Low superheat and low pulling speed ensure the quality of the slab.
  • the temperature at the cutting after continuous casting is controlled at ⁇ 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 and no shrinkage holes.
  • the looseness is not more than grade 3.
  • the requirement is to ensure the surface of the subsequently rolled bar and the low-quality.
  • the preheating section is 850 ⁇ 30°C, and the heating section is 1100. ⁇ 30 ° C, 1130 ⁇ 30 ° C in the soaking section, to ensure that the total heat period is not less than 2 hours.
  • the metallographic structure of the non-quenched and tempered steel produced by the production method provided by the embodiment is 500 times at a magnification of ferrite and pearlite (shown in FIG. 1), the actual grain size (100 times), according to GB/
  • the T6394 has a rating of about 10 (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 strength and toughness fluctuate from the core to the edge. It 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.
  • the difference from the core to the edge hardness is less than 30HB, which can effectively avoid the tool and processing caused by the hardness change. Adverse effects, and low inclusion content, high purity ( Figure 3).
  • This example provides a non-quenched and tempered steel produced by the method described in Example 1, which consists of the following chemical composition: carbon 0.35, silicon 0.30, manganese 1.60, chromium 0.20, aluminum 0.02, nickel 0.10, copper 0.20, phosphorus 0.015, sulfur 0.02, vanadium 0.05, nitrogen 0.012, and the balance is iron.
  • This embodiment provides a non-quenched and tempered steel produced by the method described in Example 1, which is composed of the following chemical components: carbon 0.47, silicon 0.40, manganese 1.40, chromium 0.10, aluminum 0.030, copper 0.10, phosphorus 0.02, sulfur 0.02, vanadium 0.05, nitrogen 0.020, and the balance is iron.
  • This embodiment provides a non-quenched and tempered steel produced by the method described in Embodiment 1, It consists of the following chemical composition: carbon 0.40, silicon 0.50, manganese 1.50, chromium 0.30, aluminum 0.010, nickel 0.08, copper 0.08, phosphorus 0.01, ⁇ 1 0.025, vanadium 0.15, nitrogen 0.018, and the balance iron.
  • This embodiment provides a non-quenched and tempered steel produced by the method described in Example 2, which is composed of the following chemical components: carbon 0.46, silicon 0.60, manganese 1.20, aluminum 0.025, nickel 0.10, copper 0.20, phosphorus 0.008, sulfur 0.023, vanadium 0.080, nitrogen 0.020, and the balance is iron.
  • This embodiment provides a non-quenched and tempered steel produced by the method described in Example 2, which is composed of the following chemical components: carbon 0.46, silicon 0.55, manganese 1.25, chromium 0.00 to 0.10, aluminum 0.025, nickel 0.05 , copper 0.08, phosphorus 0.010, sulfur 0.10, vanadium 0.080, nitrogen 0.012, and the balance is iron.
  • This embodiment provides a non-quenched and tempered steel produced by the method described in Example 2, which is composed of the following chemical components: carbon 0.38, silicon 0.40, manganese 1.28, chromium 0.08, aluminum 0.015, nickel 0.06, copper. 0.15, phosphorus 0.025, sulfur 0.040, vanadium 0.050, nitrogen 0.019, and the balance is iron.
  • the examples provide a non-quenched and tempered steel produced by the method described in Example 3, which consists of the following chemical composition: carbon 0.39, silicon 0.58, manganese 1.50, chromium 0.15, aluminum 0.025, nickel 0.09, copper 0.16 , phosphorus 0.030, sulfur 0.050, vanadium 0.080, nitrogen 0.019, and the balance is iron.
  • the embodiment provides a non-quenched and tempered steel produced by the method described in Example 3, which is composed of the following chemical composition: carbon 0.47, silicon 0.58, manganese 1.48, chromium 0.25, Aluminum 0.025, nickel 0.09, copper 0.15, sulfur 0.020, vanadium 0.250, nitrogen 0.020, and the balance iron.
  • the embodiment provides a non-quenched and tempered steel produced by the method described in Example 3, which is composed of the following chemical composition: carbon 0.38, silicon 0.58, manganese 1.28, chromium 0.25, aluminum 0.025, nickel 0.08, phosphorus 0.020 Sulfur 0.020, vanadium 0.250, nitrogen 0.015, and the balance is iron.
  • the metallographic structure at a magnification of 500 times of the core is both ferrite and pearlite (as shown in Fig. 1), and the actual grain size (100 times), according to GB
  • the /T6394 rating is 10 ⁇ 11 (as shown in Figure 2), the grain 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, from the core to the edge
  • the strength and toughness fluctuations are 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 low inclusion content, high purity (as shown in Figure 3).
  • the mechanical property data of the above Examples 4-12 are shown in Table 1 below.
  • Table 1 the non-quenched and tempered steel produced by the production method provided by the present invention has yield strength, tensile strength, elongation, and surface shrinkage.
  • the comprehensive mechanical properties such as rate and impact absorption work are excellent, and it can be seen from the performance data in Table 1 that the production method provided by Example 3 of the present invention, and the chemical composition of the steel is carbon 0.47, silicon 0.58, manganese 1.48. , chromium 0.25, aluminum 0.025, nickel 0.09, copper 0.15, sulfur 0.020, vanadium 0.250, nitrogen 0.020, and balance iron, this example has the best overall mechanical properties, ie, the overall mechanical properties of Example 11 are the best.
  • This embodiment provides a versatile non-quenched and tempered steel production method which starts with a smelting step including an electric furnace smelting step, a ladle furnace smelting step, and a refining step which are sequentially performed.
  • a smelting step including an electric furnace smelting step, a ladle furnace smelting step, and a refining step which are sequentially performed.
  • 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 1670°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.
  • the refining furnace (VD furnace) smelting step degassing is carried out 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, avoiding the introduction through the conventional nozzle It is easy to introduce air.
  • argon gas is blown at the joint between the immersion nozzle and the tundish to prevent air from entering the tundish.
  • the superheat is strictly controlled at 23 ⁇ 35 °C, and the pulling speed is controlled at 0.5m/min ⁇ 0.6. m/ min, the low superheat and continuous drawing speed of continuous casting ensure the quality of the slab.
  • the temperature at the cutting after continuous casting is controlled at ⁇ 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 and no shrinkage holes.
  • the looseness is not more than grade 3.
  • the requirement is to ensure the surface of the subsequently rolled bar and the low-quality.
  • the preheating section is 850 ⁇ 30°C. 1100 ⁇ 30°C
  • the soaking section is 1130 ⁇ 30°C
  • the total time of the soaking section is not less than 2 hours.
  • a finishing rolling step and a cooling step are performed; in the finishing rolling step, the temperature at which the bar is controlled to enter the finishing rolling step is ⁇ 850 ° C, and the bar temperature is at 850 ° C to 900 ° C.
  • Low-temperature rolling after rolling, the steel is subjected to three-stage water-cooling through a professionally controllable water-cooling equipment. The first stage of water-cooling uses strong cooling, the second stage of water-cooling uses weak cooling, and the third stage wears cold. Water cooling uses strong cooling.
  • 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 first-stage valve opening degree 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 from 150 °C to 400 °C within 5s.
  • the bar is cooled from 50 °C to 100 °C, so that the heat is quickly dissipated.
  • the bar is dispersed and placed on a cold bed and cooled by air cooling for 10-12 minutes. Finally, the bar is cooled by a superheated cover.
  • 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. Pass, in order to make The heat of the core is transferred to the surface as much as possible, and 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 cooling, and after weak cooling, the heat is transferred to the surface.

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Abstract

一种非调质钢及其生产工艺，所述非调质钢的生产工艺在精轧步骤后设置冷却步骤，强冷和弱冷交替进行冷却，强冷可以保证钢材表面温度迅速减低，弱冷可以使得钢材芯部的温度逐渐扩散到表面，随后再进行强冷，使得热量快速散出，根据实际需要，强冷和弱冷可以交替进行多次，强弱冷相结合的穿水冷却方式使得在较短的时间内钢材芯部的温度和表面的温度趋于一致，从而确保了钢材力学性能的均匀性，且提高了生产效率。

Description

一种非调质钢及其生产工艺 技术领域
本发明涉及一种非调质钢及其生产工艺，属于钢铁冶金技术领 域。
背景技术
目前， 国内机械加工行业切削用棒材多数使用 45、 40Cr及 42CrMo等普通钢， 这些棒材在作为机加工切削用原料时需进行调 质热处理，调质成本高，而且由于调质过程会增加能耗并污染环境， 同时还有一些废品损耗， 不符合现今的节能环保要求。 因此， 不需 要调质处理的可直接切削用非调质钢必将逐步替代普通钢，成为未 来发展趋势。 非调质钢是指不经过调质处理就可以达到性能要求的 机械结构钢， 采用此类钢制造零件， 可省去调质热处理工序， 具有 节省能源、材料、工艺简单等优点，可以减少环境污染、避免氧化、 脱碳、 变形、 开裂。
国内生产易切削非调质钢传统工艺为：电炉冶炼 ~精炼 ~模 铸~控轧控冷。 该种工艺在生产中的难点为： 钢材性能的控制。 现 有国内外生产厂家大多通过改善非调质钢的化学成分来达到对钢 材性能的控制， 然而， 研究证明， 单纯通过成分设计很难使得非调 质钢达到性能上的要求。
为此， 首钢总公司提出了一种新的非调质钢的生产工艺， 主要 包括： 转炉冶炼、 挡渣出钢、 钢包脱氧合金化、 LF钢包精炼、 喂 S 线、 钢包底吹氩以实现全保护浇铸、 铸坯控温、 控冷以及轧制等步 骤，其中，在轧制步骤中，加热温度 1100 ~ 1180°C，开轧温度 1020 ~ 1100 °C， 终轧温度 850 ~ 920 °C， 相对变形量为 15 ~ 35%， 轧后冷 却到 600°C后緩慢冷却到室温。 上述工艺生产的非调质钢， 通过緩 慢冷却方式在短时间内很难保证钢材芯部和表面的温度趋于一致， 很容易导致钢材表面和芯部的强度、 韧性波动很大， 力学性能严重 不均匀，采用上述工艺生产大尺寸非调质钢时（例如 φ70 ~ (pl45mm 棒材） ， 棒材表面和棒材芯部力学性能不均匀的现象更加明显。
发明内容
因此，本发明要解决的技术问题在于克服现有非调质钢生产工 艺生产出的钢材的表面力学性能和芯部力性能不均匀的缺陷，从而 提供一种非调质钢及其生产工艺，确保成品的表面力学性能和芯部 力学性能的均匀性。
为此， 本发明提供一种非调质钢， 其由重量百分比如下的化学 成分组成：碳 0.35 ~ 0.47，鞋 0.30 ~ 0.60，锰 1.20 ~ 1.60，铬 0.00 ~ 0.30， 铝 0.010 ~ 0.030，镍 0.00 ~ 0.10，铜 0.00 ~ 0.20，磷 0.000 ~ 0.020，硫 0.020 ~ 0.020，钒 0.050 ~ 0.250， 氮 0.012 ~ 0.020， 以及余量为铁。
在优选实施方案中，本发明的非调制钢由重量百分比如下的化 学成分组成： 碳 0.45 ~ 0.47，硅 0.30 ~ 0.50，锰 1.30 ~ 1.60，铬 0.00 ~ 0.20 ，铝 0.010 ~ 0.020，镍 0.00 ~ 0.08，铜 0.00 ~ 0.10，碑 0.000 ~ 0.010, 硫 0.00 ~ 0.010，钒 0.050 ~ 0.250,氮 0.012 ~ 0.020,以及余量为铁。
本发明提供一种非调质钢的生产工艺， 包括至少在精轧步骤后 进行的冷却步骤， 在所述冷却步骤中， 采用强弱冷却交替的方式使 所述钢材至少经过两段穿水冷却， 以使得在特定时间内钢材的芯部 温度与表面温度趋于一致。
在本发明提供的非调质钢的生产工艺中， 在所述冷却步骤中， 使所述钢材经过三段穿水冷却， 其中， 第一段穿水冷却采用强冷， 第二段穿水冷却采用弱冷， 第三段穿水冷却采用强冷。
在本发明提供的非调质钢的生产工艺中， 在所述冷却步骤中， 通过控制穿水冷却装置的阀门开启程度控制冷却的强弱。 在本发明提供的非调质钢的生产工艺中， 在所述冷却步骤中， 所述钢材经过穿水冷却后， 在 4 ~ 7秒内降低 100 °C ~ 400 °C， 待钢 材回温后再次降温 50 °C ~ 100°C。
在本发明提供的非调质钢的生产工艺中， 在所述冷却步骤中， 控制第一段阀门开度为 30% ~ 40%， 第二段阀门开度为 20%， 第 三段阀门开度为 30% ~ 40%, 以确保在 4 ~ 7秒使所述钢材表面温 度降低 100°C ~ 400°C。
在本发明提供的非调质钢的生产工艺中， 在所述冷却步骤中， 待钢材回温后采用喷雾冷却的方式对所述钢材进行降温冷却。
在本发明提供的非调质钢的生产工艺中， 在所述降温冷却后， 将所述钢材分散放置到冷床上进行 10 ~ 12分钟的空冷。
在本发明提供的非调质钢的生产工艺中， 在所述空冷后， 将所 述钢材叠放后进行罩冷。
本发明提供的非调质钢的生产工艺，还包括位于冷却步骤前的 精轧步骤， 在所述精轧步骤中， 控制所述钢材进入精轧步骤时的温 度≤850°〇， 在钢材温度处于 850°C ~ 900°C条件下进行低温轧制。
本发明提供的非调质钢的生产工艺，还包括位于精轧步骤之前 的冶炼步骤， 所述冶炼步骤包括依次进行的电炉冶炼步骤、 钢包炉 冶炼步骤以及精炼步骤。
在本发明提供一种非调质钢的生产工艺中，在所述电炉冶炼中 采用全铁水冶炼，终点磷含量≤0.015%，终点碳含量 0.03% ~ 0.10%, 终点温度 1620°C ~ 1700°C。
在本发明提供的非调质钢的生产工艺中，在所述钢包炉冶炼步 骤和 /或所述精炼步骤中采用碳化硅、 硅铁粉脱氧。
在本发明提供的非调质钢的生产工艺中，在所述钢包炉冶炼步 骤中， 造白渣， 并使得白渣保持时间不少于 20分钟。 在本发明提供的非调质钢的生产工艺中， 在精炼步骤中， 确保 精炼时间不少于 45分钟， 将含氢量控制在 1.5ppm以下。
在本发明提供的非调质钢的生产工艺中，还包括位于所述精炼 步骤之后的连铸步骤，在所述连铸步骤中，过热度控制在 20 ~ 35°C， 拉速控制在 0.5m/min ~ 0.6m/ min。
本发明提供的非调质钢的生产工艺，还包括连铸步骤之后的加 热步骤，在所述加热步骤中，将钢坯放入加热炉中进行加热，其中， 预热段温度控制在 850±30°C， 加热段温度控制在 1100±30°C， 均热 段温度控制在 1130±30°C， 均热段总时间不少于 2小时。
本发明提供一种非调质钢的生产工艺，该工艺依次包括如下步 骤：
( 1 ) 电炉冶炼步骤： 提供具有期望的钢组成的铁水原料，在所 述电炉冶炼中采用全铁水冶炼， 终点磷含量≤0.015%， 终点碳含量 0.03% ~ 0.10%, 终点温度 1620°C ~ 1700 °C ;
( 2 )钢包炉冶炼步骤： 其中采用碳化硅、 硅铁粉脱氧， 并且 加入石灰造白渣， 并使得白渣保持时间不少于 20分钟；
( 3 ) 以及精炼步骤： 其中进行脱气处理， 确保精炼时间不少 于 45分钟， 从而将含氢量控制在 1.5ppm以下；
( 4 )连铸步骤： 其中对精炼步骤产生的钢熔体进行连铸， 钢 熔体的过热度控制在 20 ~ 35°C，拉速控制在 0.5m/min ~ 0.6m/ min;
( 5 )加热步骤： 其中将连铸步骤产生的钢坯放入加热炉中进 行加热， 其中， 预热段温度控制在 850±30°C， 加热段温度控制在 1100±30°C , 均热段温度控制在 1130±30°C， 均热段总时间不少于 2 小时；
( 6 )精轧步骤： 其中控制所述钢材进入精轧步骤时的温度 ≤850°C， 在钢材温度处于 850°C ~ 900°C条件下进行低温轧制； 和 ( 7 )冷却步骤： 其中采用强弱冷却交替的方式使所述钢材至 少经过两段穿水冷却， 以使得在冷却冷却过程中钢材的芯部温度与 表面温度趋于一致。
本发明提供的非调质钢的生产工艺具有以下优点：
1.本发明提供的非调质钢的生产工艺， 改变以往非调质钢生产 中在精轧之前进行冷却的方式， 至少在精轧步骤后设置冷却步骤， 并且冷却方式一改现有技术中采用单一水冷或者空冷且强弱一致 的冷却方式， 将强冷和弱冷交替进行， 强冷可以保证钢材表面温度 迅速减低， 弱冷可以使得钢材芯部的温度逐渐扩散到表面， 随后再 进行强冷， 使得热量快速散出， 根据实际需要， 强冷和弱冷可以交 替进行多次， 强弱冷相结合的穿水冷却方式使得在较短的时间内钢 材芯部的温度和表面的温度即趋于一致，从而确保了钢材力学性能 的均匀性， 且提高了生产效率。
2.本发明提供的非调质钢的生产工艺， 在所述冷却步骤中， 使 所述钢材经过三段穿水冷却， 其中， 第一段穿水冷却采用强冷， 第 二段穿水冷却采用弱冷， 第三段穿水冷却采用强冷。 精轧之后的钢 材温度较高， 在第一段穿水冷却时采用强冷的方式， 使得钢材的表 面温度迅速降低， 由于热量的传递作用， 表面温度降低之后， 芯部 热量逐渐向表面传递， 为了使得芯部热量尽可能多的传递到表面， 在第二段穿水冷却中采用弱冷的方式， 弱冷之后， 热传递使得表面 温度有所升高， 再次通过强冷方式快速冷却表面， 从而使得表面热 量被迅速带走， 此时， 热传递使得表面温度和芯部温度趋于一致， 从而确保了力学性能的均匀性。
3.本发明提供的非调质钢的生产工艺， 在所述冷却步骤中， 通 过控制穿水冷却装置的阀门开启程度控制冷却的强弱， 具体地， 控 制第一段阀门开度为 30% ~ 40%， 第二段阀门开度为 20%， 第三 段阀门开度为 30% ~ 40%, 以确保在 4 ~ 7秒使所述钢材表面温度 降低 100°C ~ 400°C，通过控制阀门开启程度可以控制水流量，进而 控制穿水冷却的强弱程度， 该种控制方式非常简便， 在阀门开启一 定长度后， 将钢材穿入水中进行穿水处理， 钢材在穿水过程中， 其 表面被全方位冷却， 确保了表面冷却的均匀性。
4.本发明提供的非调质钢的生产工艺， 在所述冷却步骤中， 待 钢材回温后采用喷雾冷却的方式对所述钢材进行降温冷却。喷雾冷 却的方式是对穿水冷却的有利补充，通过喷雾冷却可以使得芯部的 热量进一步扩散到表面， 更加确保了芯部与表面温度的一致性。
5.本发明提供的非调质钢的生产工艺， 在所述降温冷却后， 将 所述钢材分散放置到冷床上进行 10 - 12分钟的空冷。 在喷雾冷却 后，将钢材分散放置到冷床上进行空冷，可以进一步补充喷雾冷却， 使得表面热量进一步散失。
6.本发明提供的非调质钢的生产工艺， 在所述空冷后， 将所述 钢材叠放后进行罩冷。 罩冷是緩慢冷却的一种方式， 为了避免上述 冷却过程过快而对钢材组织性能造成的不利影响，将所述钢材叠放 后进行罩冷， 在经过穿水冷却、 喷雾冷却以及空冷等冷却方式后， 钢材表面温度与芯部温度已经达到一致， 此时， 采用罩冷的方式， 将冷却速度降下来， 有利于改善钢材的组织性能。
7.本发明提供的非调质钢的生产工艺， 在所述钢包炉冶炼步骤 中， 造白渣， 并使得白渣保持时间不少于 20分钟，严格控制白渣保 持时间， 使得白渣的脱氧、 脱¾以及去除夹杂物的作用更加明显， 有利于提高钢的纯净度。
8.本发明提供的非调质钢的生产工艺， 在精炼步骤中， 确保精 炼时间不少于 45分钟，将含氢量控制在 1.5ppm以下， 该精炼工艺 有效的控制了氢含量， 可以更好的解决后续钢材氢致裂紋的风险； 有更充分的时间使得成分更均匀； 给予夹杂物更充分的上浮时间， 有效的解决夹杂物控制的问题， 使得成品更加纯净。
9.本发明提供的非调质钢的生产工艺， 连铸步骤中， 过热度严 格控制在 20 ~ 35°C， 拉速控制在 0.5m/min ~ 0.6m/ min， 连铸的低 过热度、 低拉速保证了铸坯的质量。
10.本发明提供的生产工艺生产的非调质钢，放大 500倍下的金 相组织为铁素体和珠光体， 实际晶粒度（100倍） ， 按 GB/T6394 评级为 10 ~ 11级， 晶粒细小， 均匀， 从芯部到边缘级差不大于 1.5 级， 钢材表面和芯部的力学性能均匀， 由芯部到边缘的强度、 韧性 波动很小， 可以有效避免一般材料在表面加工量较大后， 力学性能 达不到使用要求的缺点， 由芯部到边缘硬度差小于 30HB, 可以有 效的避免硬度变化大时对刀具、 加工产生的不利影响， 并且夹杂物 含量低， 纯净度较高。
本发明的核心在于通过控制轧制和控制轧制后的冷却步骤使 得钢材表面和芯部的性能大体一致， 从而提高了钢材的品质。 具体 的冷却控制包括：
1 )在精轧之后采用强弱冷却交替的方式使所述钢材至少经过 两段穿水冷却， 以使得在特定时间内钢材的芯部温度与表面温度趋 于一致，具体地，在精轧之后使所述钢材经过三段穿水冷却，其中， 第一段穿水冷却釆用强冷， 第二段穿水冷却采用弱冷， 第三段穿水 冷却采用强冷， 在具体的穿水冷却中， 通过控制穿水冷却装置的阀 门开启程度控制冷却的强弱。 在本发明中， 所述强冷通常指冷却 速度≥7°C/S的冷却；而所述弱冷是指冷却速度为 2-4O/S的冷却。
2 ) 穿水冷却后， 待钢材回温后采用喷雾冷却的方式对所述钢 材进行降温冷却；
3 )在所述降温冷却后，将所述钢材分散放置到冷床上进行 10 ~
-Ί- 12分钟的空冷；
4 )在所述空冷后， 将所述钢材叠放后进行罩冷。
在精轧之后通过上述方式（尤其是穿水冷却）进行冷却控制， 改变以往非调质钢生产中在精轧之前进行冷却的方式，至少在精轧 步骤后设置冷却步骤，并且冷却方式一改现有技术中采用单一水冷 或者空冷且强弱一致的冷却方式， 将强冷和弱冷交替进行， 强冷可 以保证钢材表面温度迅速减低，弱冷可以使得钢材芯部的温度逐渐 扩散到表面，随后再进行强冷，使得热量快速散出，根据实际需要， 强冷和弱冷可以交替进行多次， 强弱冷相结合的穿水冷却方式使得 在较短的时间内钢材芯部的温度和表面的温度即趋于一致，从而确 保了钢材力学性能的均匀性， 且提高了生产效率。 在此基础之上， 后续的喷雾冷却、 空冷以及罩冷方式的联合控制， 使得芯部温度不 断的散向表面， 而表面温度不断的被带走， 并且， 上述冷却方式的 结合使得冷却速度比较适宜， 在空冷之后采用罩冷， 使得钢材表面 温度与芯部温度一致的情况下， 冷却速度不至于过快， 提高了综合 力学性能。
附图说明
为了使本发明的内容更容易被清楚的理解， 下面根据本发明的 具体实施例并结合附图， 对本发明作进一步详细的说明， 其中
图 1是采用本发明的生产方法生产的非调质钢在放大 500倍下 的金相图片；
图 2是反映采用本发明的生产方法生产的非调质钢的晶粒度的 图片；
图 3是反映采用本发明的生产方法生产的非调质钢的夹杂物情 况的图片。
具体实施方式 实施例 1
本实施例提供一种非调质钢的生产方法， 包括精轧步骤以及在 精轧之后的冷却步骤， 其中， 在所述精轧步骤中， 控制棒材进入精 轧步骤时的温度≤850°〇，在棒材温度处于 850 °C ~ 900°C条件下进行 低温轧制； 轧制后通过专业可控的穿水冷却设备对钢材进行三段穿 水冷却， 第一段穿水冷却采用强冷， 第二段穿水冷却采用弱冷， 第 三段穿水冷却采用强冷。
在此， 需要说明的是， 控制穿水冷却强弱的方式有很多， 在本 实施例中， 通过控制穿水冷却装置的阀门开启程度来控制水流量， 以此来控制冷却强弱的目的， 具体地， 第一段阀门开度为 30% ~ 40%, 第二段阀门开度为 20%， 第三段阀门开度为 30% ~ 40%， 可确保 5s内降低棒材表面温度 150°C ~ 400 °C， 之后待棒材回温后 采用喷雾冷却的方式将棒材降温 50 °C ~ 100 °C，使其热量快速散出， 然后将棒材分散开来放置到冷床上采用空冷方式冷却 10-12 分钟， 最后下冷床将棒材叠加罩冷。
本实施例的非调质钢的生产方法，使所述棒材经过三段穿水冷 却， 其中， 笫一段穿水冷却采用强冷， 第二段穿水冷却采用弱冷， 第三段穿水冷却釆用强冷。 精轧之后的棒材温度较高， 在第一段穿 水冷却时采用强冷的方式， 使得棒材的表面温度迅速降低， 由于热 量的传递作用， 表面温度降低之后， 芯部热量逐渐向表面传递， 为 了使得芯部热量尽可能多的传递到表面，在第二段穿水冷却中采用 弱冷方式， 以使得冷却过程中预留较多的时间给芯部进行热传递， 弱冷之后， 热传递使得表面温度有所升高， 再次通过强冷方式快速 冷却表面， 从而使得表面热量被迅速带走， 此时， 热传递使得表面 温度和芯部温度趋于一致， 从而确保了力学性能的均匀性。 实施例 2
本实施例提供一种非调质钢的生产方法，其是在实施例 1基础 之上的进一步改进， 相对于实施例 1来说， 还包括位于精轧步骤之 前的冶炼步骤， 所述冶炼步骤包括依次进行的电炉冶炼步骤、 钢包 炉冶炼步骤以及精炼步骤。
在电炉冶炼步骤中， 采用全铁水冶炼， 严格控制出钢前磷含量
<0.015%,终点碳含量 0.03% ~ 0.10%,终点温度 1670°C ~ 1700 °C， 电炉冶炼较传统的转炉冶炼可以更好的控制下渣操作。
在钢包炉 （LF 炉） 冶炼步骤中， 使用碳化硅、 硅铁粉脱氧， 加入石灰造白渣， 白渣保持时间不少于 20分钟， 以使得白渣能够 较为彻底的清除夹杂物。
在精炼炉 （VD炉） 冶炼步骤中， 进行脱气处理， 确保含氢量 控制在 1.5ppm以下， 确保精炼时间不少于 45分钟。
用 LF炉 +VD炉精炼的优点： 相对于传统的仅用 LF炉精炼来 说， 该精炼工艺有效的控制了氢含量， 可以更好的解决后续棒材氢 至裂紋的风险； 有更充分的时间使得成分更均勾； 给予夹杂物有更 充分的上浮时间， 有效的解决夹杂物控制的问题。
实施例 3
本实施例提供一种非调质钢的生产方法， 其是在实施例 1或 2 基础上的进一步改进， 在本实施例中， 对连铸步骤以及加热步骤进 行改进， 连铸步骤和加热步骤均位于精炼步骤之后， 而又位于轧制 步骤和穿水冷却步骤之前。
连铸步骤中， 通过侵入式水口将中间包中的铁水引入结晶器， 避免了通过传统水口引入时易于引入空气的问题， 另外， 在浸入式 水口与中间包的结合部位吹氩气， 以避免空气进入中间包， 过热度 严格控制在 23 ~ 35°C， 拉速控制在 0.5m/min ~ 0.6m/ min， 连铸的 低过热度、 低拉速保证了铸坯的质量。 连铸后切割时据切处的温度 控制在≤820°C， 切割后， 需人工检查铸坯表面， 确保无明显缺陷， 取铸坯低倍样， 确保铸坯无裂紋， 无缩孔， 中心疏松不大于 3级， 该要求是为了保证后续轧制出的棒材表面与低倍的质量，铸坯检查 合格后，送往加热炉进行加热，预热段 850±30°C，加热段 1100±30°C， 均热段 1130±30°C， 确保均热段总时间不少于 2小时。
采用本实施例提供的生产方法生产出的非调质钢的放大 500倍 下的金相组织为铁素体和珠光体 (图 1所示)，实际晶粒度（ 100倍）， 按 GB/T6394评级为 10级左右（图 2所示） ， 晶粒细小， 均匀， 从芯部到边缘级差不大于 1.5级，钢材表面和芯部的力学性能均匀， 由芯部到边缘的强度、 韧性波动很小， 可以有效避免一般材料在表 面加工量较大后， 力学性能达不到使用要求的缺点， 由芯部到边缘 硬度差小于 30HB, 可以有效的避免硬度变化大时对刀具、 加工产 生的不利影响， 并且夹杂物含量低， 纯净度较高 （图 3所示） 。
实施例 4
本实施例提供一种采用实施例 1所述的方法生产的非调质钢， 其由重量百分比如下的化学成分组成： 碳 0.35，硅 0.30，锰 1.60，铬 0.20，铝 0.02，镍 0.10，铜 0.20，磷 0.015，硫 0.02，钒 0.05， 氮 0.012， 以 及余量为铁。
实施例 5
本实施例提供一种采用实施例 1所述的方法生产的非调质钢， 其由重量百分比如下的化学成分组成： 碳 0.47，硅 0.40，锰 1.40，铬 0.10，铝 0.030，铜 0.10，磷 0.02，硫 0.02，钒 0.05， 氮 0.020， 以及余量为 铁。
实施例 6
本实施例提供一种采用实施例 1所述的方法生产的非调质钢， 其由重量百分比如下的化学成分组成： 碳 0.40，硅 0.50，锰 1.50，铬 0.30，铝 0.010，镍 0.08，铜 0.08，磷 0.01,^1 0.025，钒 0.15， 氮 0.018， 以 及余量为铁。
实施例 7
本实施例提供一种采用实施例 2所述的方法生产的非调质钢， 其由重量百分比如下的化学成分组成： 碳 0.46，硅 0.60，锰 1.20，铝 0.025，镍 0.10，铜 0.20，磷 0.008，硫 0.023，钒 0.080， 氮 0.020， 以及余 量为铁。
实施例 8
本实施例提供一种采用实施例 2所述的方法生产的非调质钢， 其由重量百分比如下的化学成分组成： 碳 0.46，硅 0.55，锰 1.25，铬 0.00 ~ 0.10，铝 0.025，镍 0.05，铜 0.08，磷 0.010，硫 0.10, 钒 0.080， 氮 0.012， 以及余量为铁。
实施例 9
本实施例提供一种采用实施例 2所述的方法生产的非调质钢， 其由重量百分比如下的化学成分组成： 碳 0.38，硅 0.40，锰 1.28，铬 0.08，铝 0.015，镍 0.06，铜 0.15，磷 0.025，硫 0.040， 钒 0.050， 氮 0.019， 以及余量为铁。
实施例 10
实施例提供一种采用实施例 3所述的方法生产的非调质钢， 其 由重量百分比如下的化学成分组成：碳 0.39，硅 0.58，锰 1.50，铬 0.15， 铝 0.025，镍 0.09，铜 0.16，磷 0.030，硫 0.050，钒 0.080, 氮 0.019， 以及 余量为铁。
实施例 11
实施例提供一种采用实施例 3所述的方法生产的非调质钢， 其 由重量百分比如下的化学成分组成：碳 0.47，硅 0.58，锰 1.48，铬 0.25， 铝 0.025，镍 0.09，铜 0.15，硫 0.020，钒 0.250， 氮 0.020， 以及余量为 铁。
实施例 12
实施例提供一种采用实施例 3所述的方法生产的非调质钢， 其 由重量百分比如下的化学成分组成：碳 0.38，硅 0.58，锰 1.28，铬 0.25, 铝 0.025，镍 0.08，磷 0.020，硫 0.020， 钒 0.250， 氮 0.015， 以及余量为 铁。
上述实施例 4-12的非调质钢， 芯部放大 500倍下的金相组织 为都为铁素体和珠光体（如图 1所示） ， 实际晶粒度（100倍） ， 按 GB/T6394评级为 10 ~ 11级（如图 2所示）， 晶粒细小， 均匀， 从芯部到边缘级差都不大于 1.5级， 钢材表面和芯部的力学性能均 匀， 由芯部到边缘的强度、 韧性波动很小， 可以有效避免一般材料 在表面加工量较大后， 力学性能达不到使用要求的缺点， 由芯部到 边缘硬度差小于 30HB, 可以有效的避免硬度变化大时对刀具、 加 工产生的不利影响，并且夹杂物含量低，纯净度较高（如图 3所示）。
上述实施例 4-12的力学性能数据见下表 1，从表 1中可以看出， 采用本发明提供的生产方法生产的非调质钢， 在屈服强度、 抗拉强 度、 延伸率、 面缩率、 冲击吸收功等综合力学性能优良， 并且， 从 表 1中的性能数据可以看出，采用本发明的实施例 3提供的生产方 法， 且钢的化学组成为碳 0.47，硅 0.58，锰 1.48，铬 0.25，铝 0.025，镍 0.09，铜 0.15，硫 0.020, 钒 0.250， 氮 0.020， 以及余量为铁， 这一实 施例的综合力学性能最好， 即实施例 11的综合力学性能最好。
从下表性能数据可以看出，本发明提供的采用上述方法生产的 非调质钢，完全可以替代调质 42CrMo钢直接进行切削加工，并且， 在综合力学性能上更加优良。 表 1 实施例 4-12的力学性能数据
Figure imgf000016_0001
实施例 13
本实施例提供一种通用性的非调质钢生产方法，该方法以冶炼 步骤开始，所述冶炼步骤包括依次进行的电炉冶炼步骤、钢包炉冶炼 步骤以及精炼步骤。 在电炉冶炼步骤中， 采用全铁水冶炼， 严格控 制出钢前磷含量≤0.015%， 终点碳含量 0.03% ~ 0.10%， 终点温度 1670°C - 1700°C , 电炉冶炼较传统的转炉冶炼可以更好的控制下渣 操作。 在钢包炉（LF炉）冶炼步骤中， 使用碳化硅、硅铁粉脱氧， 加入石灰造白渣， 白渣保持时间不少于 20分钟， 以使得白渣能够 较为彻底的清除夹杂物。 在精炼炉 （VD炉） 冶炼步骤中， 进行脱 气处理， 确保含氢量控制在 1.5ppm以下， 确保精炼时间不少于 45 分钟。
用 LF炉 +VD炉精炼的优点： 相对于传统的仅用 LF炉精炼来 说， 该精炼工艺有效的控制了氢含量， 可以更好的解决后续棒材氢 至裂紋的风险； 有更充分的时间使得成分更均句； 给予夹杂物有更 充分的上浮时间， 有效的解决夹杂物控制的问题。
在精炼步骤之后进行连铸步骤。 在所述连铸步骤中， 通过侵入 式水口将中间包中的铁水引入结晶器，避免了通过传统水口引入时 易于引入空气的问题， 另外， 在浸入式水口与中间包的结合部位吹 氩气， 以避免空气进入中间包， 过热度严格控制在 23 ~ 35°C， 拉速 控制在 0.5m/min ~ 0.6m/ min， 连铸的低过热度、 低拉速保证了铸 坯的质量。 连铸后切割时据切处的温度控制在≤820°C， 切割后， 需 人工检查铸坯表面， 确保无明显缺陷， 取铸坯低倍样， 确保铸坯无 裂紋， 无缩孔， 中心疏松不大于 3级， 该要求是为了保证后续轧制 出的棒材表面与低倍的质量， 铸坯检查合格后， 送往加热炉进行加 热步骤，预热段 850±30°C，加热段 1100±30°C，均热段 1130±30°C， 确保均热段总时间不少于 2小时。
在加热步骤之后进行精轧步骤和冷却步骤;， 在所述精轧步骤 中， 控制棒材进入精轧步骤时的温度≤850°C， 在棒材温度处于 850°C ~ 900°C条件下进行低温轧制； 轧制后通过专业可控的穿水冷 却设备对钢材进行三段穿水冷却， 第一段穿水冷却采用强冷， 第二 段穿水冷却采用弱冷， 第三段穿水冷却采用强冷。
在本实施例中，通过控制穿水冷却装置的阀门开启程度来控制 水流量， 以此来控制冷却强弱的目的， 具体地， 第一段阀门开度为 30% ~ 40%, 第二段阀门开度为 20%， 第三段阀门开度为 30% ~ 40%, 可确保 5s内降低棒材表面温度 150 °C ~ 400 °C， 之后待棒材 回温后采用喷雾冷却的方式将棒材降温 50°C ~ 100 °C , 使其热量快 速散出， 然后将棒材分散开来放置到冷床上采用空冷方式冷却 10-12分钟， 最后下冷床将棒材叠加罩冷。
在本实施例的生产方法中， 使所述棒材经过三段穿水冷却， 其 中， 第一段穿水冷却采用强冷， 第二段穿水冷却采用弱冷， 第三段 穿水冷却采用强冷。 精轧之后的棒材温度较高， 在第一段穿水冷却 时采用强冷的方式， 使得棒材的表面温度迅速降低， 由于热量的传 递作用， 表面温度降低之后， 芯部热量逐渐向表面传递， 为了使得 芯部热量尽可能多的传递到表面，在第二段穿水冷却中采用弱冷方 式， 以使得冷却过程中预留较多的时间给芯部进行热传递， 弱冷之 后， 热传递使得表面温度有所升高， 再次通过强冷方式快速冷却表 面， 从而使得表面热量被迅速带走， 此时， 热传递使得表面温度和 芯部温度趋于一致， 从而确保了力学性能的均匀性。 显然， 上述实施例仅是为清楚地说明所作的举例， 而并非对实 施方式的限定。 对于所属领域的普通技术人员来说， 在上述说明的 基础上还可以做出其它不同形式的变化或变动。这里无需也无法对 所有的实施方式予以穷举。 而由此所引伸出的显而易见的变化或变 动仍处于本发明创造的保护范围之中。

Claims

权 利 要 求
1. 一种非调质钢，其包括重量百分比如下的化学成分:碳 0.35 ~ 0.47，硅 0.30 ~ 0.60，锰 1.20 ~ 1.60，铬 0.00 ~ 0.30 ，铝 0.010 ~ 0.030，镍 0.00 ~ 0.10，铜 0.00 ~ 0.20，磚 0.000 ~ 0.030,¾ 0.020 ~ 0.050，钒 0.050 ~ 0.250, 氮 0.012 ~ 0.020， 余量为铁。
2. 根据权利要求 1所述的非调质钢， 其包括重量百分比如下的 化学成分：碳 0.45 ~ 0.47，鞋 0.30 ~ 0.50，锰 1.30 ~ 1.60，铬 0.00 ~ 0.20， 铝 0.010 ~ 0.020，镍 0.00 ~ 0.08，铜 0.00 ~ 0.10，磷 0.000 ~ 0.010，硫 0.02 ~ 0.025，钒 0.050 ~ 0.250, 氮 0.012 ~ 0.020, 余量为铁。
3. 一种生产权利要求 1或 2所述的非调质钢的生产工艺， 包括 至少在精轧步骤后进行的冷却步骤， 其特征在于： 在所述冷却步骤 中， 采用强弱冷却交替的方式使所述钢材至少经过两段穿水冷却， 以使得在特定时间内钢材的芯部温度与表面温度趋于一致。
4. 根据权利要求 3所述的非调质钢的生产工艺， 其特征在于： 在所述冷却步骤中， 使所述钢材经过三段穿水冷却， 其中， 第一段 穿水冷却采用强冷， 第二段穿水冷却采用弱冷， 第三段穿水冷却采 用强冷。
5. 根据权利要求 3或 4所述的非调质钢的生产工艺， 其特征在 于： 在所述冷却步骤中， 通过控制穿水冷却装置的阀门开启程度控 制冷却的强弱。
6. 根据权利要求 3 ~ 5中任一项所述的非调质钢的生产工艺，其 特征在于： 在所述冷却步骤中， 所述钢材经过穿水冷却后， 在 4 ~ 7 秒内降低 100°C ~ 400 °C， 待钢材回温后再次降温 50 °C ~ 100 °C。
7. 根据权利要求 5或 6所述的非调质钢的生产工艺， 其特征在 于： 在所述冷却步骤中， 控制第一段阀门开度为 30% ~ 40%， 第二 段阀门开度为 20%， 第三段阀门开度为 30% ~ 40%， 以确保在 4 ~ 7秒使所述钢材表面温度降低 100 °C ~ 400°C。
8. 根据权利要求 6或 7所述的非调质钢的生产工艺， 其特征在 于： 在所述冷却步骤中， 待钢材回温后采用喷雾冷却的方式对所述 钢材进行降温冷却。
9. 根据权利要求 6 ~ 8中任一项所述的非调质钢的生产工艺，其 特征在于： 在所述降温冷却后， 将所述钢材分散放置到冷床上进行 10 - 12分钟的空冷。
10. 根据权利要求 9所述的非调质钢的生产工艺， 其特征在于： 在所述空冷后， 将所述钢材叠放后进行罩冷。
11. 根据权利要求 3 ~ 12中任一项所述的非调质钢的生产工艺， 其特征在于： 还包括位于冷却步骤前的精轧步骤， 在所述精轧步骤 中， 控制所述钢材进入精轧步骤时的温度≤850" ， 在钢材温度处于 850 °C ~ 900 °C条件下进行低温轧制。
12. 根据权利要求 3 ~ 11中任一项所述的非调质钢的生产工艺， 其特征在于： 还包括位于精轧步骤之前的冶炼步骤， 所述冶炼步骤 包括依次进行的电炉冶炼步骤、 钢包炉冶炼步骤以及精炼步骤。
13. 根据权利要求 12所述的非调质钢的生产工艺，其特征在于： 在所述电炉冶炼中采用全铁水冶炼， 终点磷含量≤0.015%， 终点碳 含量 0.03% ~ 0.10%, 终点温度 1620°C ~ 1700 °C。
14. 根据权利要求 12或 13所述的非调质钢的生产工艺，其特征 在于：在所述钢包炉冶炼步骤和 /或所述精炼步骤中采用碳化硅、硅 铁粉脱氧。
15. 根据权利要求 12 ~ 14中任一项所述的非调质钢的生产工艺， 其特征在于： 在所述钢包炉冶炼步骤中， 造白渣， 并使得白渣保持 时间不少于 20分钟。
16. 根据权利要求 12 ~ 15中任一项所述的非调质钢的生产工艺， 其特征在于： 在精炼步骤中， 确保精炼时间不少于 45分钟， 将含 氢量控制在 1.5ppm以下。
17. 根据权利要求 16所述的非调质钢的生产工艺，其特征在于： 还包括位于所述精炼步骤之后的连铸步骤， 在所述连铸步骤中， 过 热度控制在 20 ~ 35°C， 拉速控制在 0.5m/min ~ 0.6m/ min。
18. 根据权利要求 17所述的非调质钢的生产工艺，其特征在于： 还包括连铸步骤之后的加热步骤， 在所述加热步骤中， 将钢坯放入 加热炉中进行加热， 其中，预热段温度控制在 850±30°C， 加热段温 度控制在 1100±30°C， 均热段温度控制在 1130±30°C， 均热段总时 间不少于 2小时。
19. 一种生产非调质钢的生产工艺， 该工艺依次包括如下步骤：
( 1 ) 电炉冶炼步骤： 提供具有期望的钢组成的铁原料，在所述 电炉冶炼中采用全铁水冶炼， 终点磷含量≤0.015%， 终点碳含量 0.03% ~ 0.10%, 终点温度 1620°C ~ 1700 °C ;
( 2 )钢包炉冶炼步骤： 其中采用碳化硅、 硅铁粉脱氧， 并且 加入石灰造白渣， 并使得白渣保持时间不少于 20分钟；
( 3 ) 以及精炼步骤： 其中进行脱气处理， 确保精炼时间不少 于 45分钟， 从而将含氢量控制在 1.5ppm以下；
( 4 )连铸步骤： 其中对精炼步骤产生的钢熔体进行连铸， 钢 熔体的过热度控制在 20 ~ 35°C，拉速控制在 0.5m/min ~ 0.6m/ min;
( 5 )加热步骤： 其中将连铸步骤产生的钢坯放入加热炉中进 行加热， 其中， 预热段温度控制在 850±30°C， 加热段温度控制在 1100±30°C , 均热段温度控制在 1130±30°C， 均热段总时间不少于 2 小时；
( 6 )精轧步骤： 其中控制所述钢材进入精轧步骤时的温度 ≤850°C， 在钢材温度处于 850°C ~900°C条件下进行低温轧制； 和
(7)冷却步骤： 其中采用强弱冷却交替的方式使所述钢材至 少经过两段穿水冷却， 以使得在冷却过程中钢材的芯部温度与表面 温度趋于一致。
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