CN114686752A - Production method for improving surface quality of Nb-containing non-tempered steel continuous casting square billet - Google Patents
Production method for improving surface quality of Nb-containing non-tempered steel continuous casting square billet Download PDFInfo
- Publication number
- CN114686752A CN114686752A CN202210410194.7A CN202210410194A CN114686752A CN 114686752 A CN114686752 A CN 114686752A CN 202210410194 A CN202210410194 A CN 202210410194A CN 114686752 A CN114686752 A CN 114686752A
- Authority
- CN
- China
- Prior art keywords
- rolling
- continuous casting
- heating
- percent
- surface quality
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 54
- 239000010959 steel Substances 0.000 title claims abstract description 54
- 238000009749 continuous casting Methods 0.000 title claims abstract description 24
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- 238000010438 heat treatment Methods 0.000 claims abstract description 43
- 238000005096 rolling process Methods 0.000 claims abstract description 31
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 20
- 238000007670 refining Methods 0.000 claims abstract description 13
- 229910052742 iron Inorganic materials 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims abstract description 9
- 238000010583 slow cooling Methods 0.000 claims abstract description 6
- 238000009628 steelmaking Methods 0.000 claims abstract description 5
- 239000010955 niobium Substances 0.000 claims description 24
- 238000001816 cooling Methods 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- 229910052758 niobium Inorganic materials 0.000 claims description 12
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 229910052760 oxygen Inorganic materials 0.000 claims description 9
- 239000001301 oxygen Substances 0.000 claims description 9
- 229910052720 vanadium Inorganic materials 0.000 claims description 9
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 9
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 8
- 238000000137 annealing Methods 0.000 claims description 8
- 229910052804 chromium Inorganic materials 0.000 claims description 8
- 239000011651 chromium Substances 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- 238000004321 preservation Methods 0.000 claims description 8
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 7
- 229910052748 manganese Inorganic materials 0.000 claims description 7
- 239000011572 manganese Substances 0.000 claims description 7
- 238000005266 casting Methods 0.000 claims description 6
- 238000005097 cold rolling Methods 0.000 claims description 6
- 238000005098 hot rolling Methods 0.000 claims description 6
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 5
- 239000011574 phosphorus Substances 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 5
- 229910052710 silicon Inorganic materials 0.000 claims description 5
- 239000010703 silicon Substances 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 239000011593 sulfur Substances 0.000 claims description 5
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 4
- 238000007664 blowing Methods 0.000 claims description 4
- 239000003546 flue gas Substances 0.000 claims description 4
- 239000000446 fuel Substances 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 2
- 238000001514 detection method Methods 0.000 abstract 1
- 238000009489 vacuum treatment Methods 0.000 abstract 1
- 239000000463 material Substances 0.000 description 10
- 230000007547 defect Effects 0.000 description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 4
- 238000005242 forging Methods 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 229910052719 titanium Inorganic materials 0.000 description 4
- 239000010936 titanium Substances 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910000617 Mangalloy Inorganic materials 0.000 description 1
- QFGIVKNKFPCKAW-UHFFFAOYSA-N [Mn].[C] Chemical compound [Mn].[C] QFGIVKNKFPCKAW-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- SJKRCWUQJZIWQB-UHFFFAOYSA-N azane;chromium Chemical compound N.[Cr] SJKRCWUQJZIWQB-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- UFGZSIPAQKLCGR-UHFFFAOYSA-N chromium carbide Chemical compound [Cr]#C[Cr]C#[Cr] UFGZSIPAQKLCGR-UHFFFAOYSA-N 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910003470 tongbaite Inorganic materials 0.000 description 1
- 229940088594 vitamin Drugs 0.000 description 1
- 229930003231 vitamin Natural products 0.000 description 1
- 235000013343 vitamin Nutrition 0.000 description 1
- 239000011782 vitamin Substances 0.000 description 1
- 150000003722 vitamin derivatives Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- 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
- C21D1/26—Methods of annealing
-
- 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
-
- 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
-
- 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
- C21D8/0236—Cold 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
- C21D8/02—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
- C21D8/0273—Final recrystallisation annealing
-
- 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
- C22C38/02—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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium 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
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
Landscapes
- 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)
- Metal Rolling (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention belongs to the technical field of steel rolling, and particularly relates to a production method for improving the surface quality of an Nb-containing non-tempered steel continuous casting square billet. The method comprises the following steps: electric furnace steel making → LF refining → VD vacuum treatment → continuous casting → slow cooling → heating → rolling → finishing → detection → warehousing; through strict control of conditions of all the steps, the iron scale on the surface of the obtained steel is obviously reduced, the surface of the steel is light blue, the average thickness of the iron scale is reduced, the surface smoothness is greatly improved, and the surface quality improvement effect is obvious.
Description
Technical Field
The invention belongs to the technical field of steel rolling, and particularly relates to a production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets.
Background
Non-heat treated steel includes non-heat treated steel for hot forging, non-heat treated steel for direct cutting, cold work strengthened non-heat treated steel and high toughness non-heat treated steel. The non-quenched and tempered steel for hot forging is used for hot forging pieces (such as crankshafts, connecting rods and the like), the hot rolled pieces for the non-quenched and tempered steel for direct cutting are directly machined into parts, the cold-work strengthened non-quenched and tempered steel is used for standard parts (such as nuts and the like), and the high-toughness non-quenched and tempered steel is used for parts requiring higher toughness. The mechanical properties of non-quenched and tempered steels depend on the microstructure of the matrix and the strengthening of the precipitated phases.
The non-quenched and tempered steel is prepared by adding vanadium, titanium and niobium microalloying elements on the basis of medium carbon manganese steel, so that the vanadium, titanium and niobium microalloying elements are dissolved in austenite in the heating process, and the solid solubility of the vanadium, titanium and niobium in the austenite is reduced along with cooling. The microalloying elements vanadium, titanium, niobium will precipitate in the form of fine carbides and nitrides in the previously precipitated ferrite and pearlite. These precipitates are in a coherent relationship with the parent phase, and strengthen the steel. The mechanical property of the steel in a hot rolling state, a forging state or a normalizing state reaches or approaches that of the prepared steel, so that the production period is shortened, and the energy is saved.
The increase of waste products caused by poor surface quality can cause cost increase and resource waste, so a method needs to be found to solve the problem and improve the product qualification rate.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets.
The present invention achieves the above-described object by the following technical means.
A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets comprises the following steps: electric furnace steel making → LF refining → VD vacuum processing → continuous casting → slow cooling → heating → rolling → finishing → detecting → warehousing, wherein,
the molten steel is prepared by the following components in percentage by mass: carbon: 0.3 to 0.6 percent; silicon: 0.4-0.6%; manganese: 0.5-1.3%; chromium: 0.03-0.1%; vanadium: 0.05 to 0.15 percent; niobium: 0.005-0.075%; oxygen: 0.02-0.05%; nitrogen: 0.02-0.6%; sulfur: 0.01 to 0.035 percent; phosphorus: 0.03-0.04%, the balance being iron and unavoidable impurities.
The LF refining step comprises the following steps: the LF single-link refining is adopted, the soft blowing time is not less than 15 minutes, the existence of impurities is effectively reduced, and the LF treatment period is more than or equal to 20 minutes.
The continuous casting step comprises: and in the continuous casting process, the pouring is protected in the whole process, the fluctuation of the liquid level of the molten steel and the stability of superheat degree are kept, and a casting blank with stable quality is obtained.
Slowly cooling a casting blank: the temperature of slow cooling entering the pit is more than or equal to 600 ℃, and the temperature of leaving the pit is less than or equal to 200 ℃;
the heating comprises preheating, heating for the first section and heating for the second section: the temperature of the preheating section is less than or equal to 700 ℃, and the time of the preheating section is more than or equal to 125 minutes; the heating section comprises a first heating section and a second heating section, the temperature of the first heating section is 1140-1160 ℃, the temperature of the second heating section is 1100-1180 ℃, the time of the heating section is heating for a first time period and heating for a second time period, and the time of the heating section is controlled to be 100-130 minutes; the air-fuel ratio is set as: the residual oxygen concentration of the flue gas is controlled to be 1% -1.6%, and the air excess coefficient in the first period is controlled to be 0.85-0.95.
The rolling comprises rough rolling, finish rolling and final rolling, wherein the start rolling temperature of the finish rolling is 1000-1070 ℃, and the final rolling temperature range is 900-930 ℃;
annealing temperature after hot rolling is 1000-1050 ℃, and heat preservation time is 10-20 s;
annealing temperature after cold rolling is 1000-1050 ℃, and heat preservation time is 10-20 s; the cold rolling processing technology can obtain uniform and fine grain structures, thereby ensuring that the material has good plasticity; and the surface defects of partial hot rolled plates can be eliminated, and the surface quality is obviously improved.
And the cooling step after rolling adopts an ultra-fast cooling and laminar cooling mode, so that the high-temperature cooling time in the air is shortened.
The steel plate obtained by the rolling method has high surface quality, high surface smoothness, no pitted surface and no water ripple; the depth of any scratch is less than or equal to 0.1mm, and the length is less than or equal to 5 mm.
Carbon: steel can perform solid solution strengthening and is inexpensive, but too high a carbon content causes deterioration in properties such as toughness and weldability.
Silicon: the steel can play roles of deoxidation and strengthening, but the steel surface with too high Si content can generate red iron sheet. When the content of Si is higher, the diameters of pores in the iron sheet are comparedThe scale is large, cracks during air cooling are easy to stop in the middle of the thickness of the scale, the scale stripping performance is poor, and the scale residue is generated during dephosphorization. The residue of iron scale can cause Fe2O3The proportion is higher, so the iron scale is red.
Manganese: the austenitizing element can effectively enlarge an austenite phase region, and can also improve the binding force among crystal grains and improve the strength and toughness of the material. Manganese also plays a role in solid solution strengthening in steel to form a solid solution, so that the hardness and strength of ferrite and austenite in the steel are improved; however, too high manganese content leads to severe center segregation and reduces the toughness of the wheel steel.
Chromium: chromium is an important element for improving the corrosion resistance, and when the content of chromium is too low, the corrosion resistance is poor and the use requirement cannot be met; but when the temperature is too high, the production difficulty is increased, hot rolling roller sticking defects and the like are easily generated, and the surface quality of the material is further reduced;
vanadium: the steel has a plurality of excellent physical properties and chemical properties, is called as metal vitamin, is mostly applied to steel, and increases the strength, toughness and wear resistance of the steel by refining the structure and grains of the steel and increasing the coarsening temperature of the grains.
Niobium: a certain amount of niobium is added to stabilize carbon and nitrogen of the material and refine the structure. Because niobium has much higher affinity with carbon and nitrogen than chromium, niobium preferentially combines with carbon and nitrogen to form uniform and fine NbC or NbN particles, thereby preventing or reducing the formation of chromium carbide and nitride, and improving the intergranular corrosion resistance of the material. The fine NbC or NbN particles can refine the material structure to obtain uniform and fine equiaxed grain structure, thereby improving the strength and plasticity of the material. The fine NbC or NbN particles can reduce or eliminate the generation of plate grain defects on the surface of the material while refining the structure, thereby enabling the surface of the material to become smooth and fine and improving the surface quality.
Oxygen, nitrogen, sulfur, phosphorus: the elements are strictly controlled, and influence the structural performance of the hot rolled coil, so that the burst rate and the micro-crack rate of the steel are increased.
Residual elements: and residual elements are strictly controlled, and the influence of the residual elements on the performance of the steel coil is reduced.
The invention has the beneficial effects that:
the steel surface oxide scale obtained by the method is obviously reduced, the surface is light blue, the average oxide scale thickness is reduced, the surface smoothness is greatly improved, and the surface quality improvement effect is obvious.
Detailed Description
The present invention will be further described with reference to the following specific examples, but the scope of the present invention is not limited thereto.
A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets comprises the following steps: electric furnace steel making → LF refining → VD vacuum processing → continuous casting → slow cooling → heating → rolling → finishing → detecting → warehousing, wherein,
the steel is smelted by an electric furnace, and the molten steel comprises the following components in percentage by mass: carbon: 0.5 percent; silicon: 0.5 percent; manganese: 0.8 percent; chromium: 0.06 percent; vanadium: 0.08 percent; niobium: 0.06 percent; oxygen: 0.03 percent; nitrogen: 0.05 percent; sulfur: 0.025 percent; phosphorus: 0.03%, the remainder being iron and unavoidable impurities.
The LF refining step comprises the following steps: LF single refining is used, soft blowing time is 20 minutes, inclusion existence is effectively reduced, and an LF treatment period is 40 minutes.
The continuous casting step comprises the following steps: and in the continuous casting process, the pouring is protected in the whole process, the fluctuation of the liquid level of the molten steel and the stability of superheat degree are kept, and a casting blank with stable quality is obtained.
Slowly cooling a casting blank: slowly cooling to 700 ℃ of pit entering temperature and 180 ℃ of pit leaving temperature;
the heating comprises preheating, heating for the first section and heating for the second section: the temperature of the preheating section is 500 ℃, and the time of the preheating section is 125 minutes; the heating section comprises a first heating section and a second heating section, the temperature of the first heating section is 1150 ℃, the temperature of the second heating section is 1180 ℃, the time of the heating section is heating for a first period of time and heating for a second period of time, and the time of the heating section is controlled to be 120 minutes; the air-fuel ratio is set as: the residual oxygen concentration of the flue gas is controlled to be 1% -1.6%, and the air excess coefficient in the first period is controlled to be 0.85-0.95.
The rolling comprises rough rolling, finish rolling and final rolling, wherein the start rolling temperature of the finish rolling is 1050 ℃, and the final rolling temperature range is 920 ℃;
the annealing temperature after hot rolling is 1020 ℃, and the heat preservation time is 15 s;
the annealing temperature after cold rolling is 1030 ℃, and the heat preservation time is 20 s; the cold rolling processing technology can obtain uniform and fine grain structures, thereby ensuring that the material has good plasticity; and the surface defects of partial hot rolled plates can be eliminated, and the surface quality is obviously improved.
And the cooling step after rolling adopts an ultra-fast cooling and laminar cooling mode, so that the high-temperature cooling time in the air is shortened.
The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.
Claims (7)
1. A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets comprises the following steps: electric furnace steel making → LF refining → VD vacuum processing → continuous casting → slow cooling → heating → rolling → finishing → detecting → warehousing, which is characterized in that:
the molten steel is prepared by the following components in percentage by mass: carbon: 0.3 to 0.6 percent; silicon: 0.4-0.6%; manganese: 0.5-1.3%; chromium: 0.03-0.1%; vanadium: 0.05 to 0.15 percent; niobium: 0.005-0.075%; oxygen: 0.02-0.05%; nitrogen: 0.02-0.6%; sulfur: 0.01 to 0.035 percent; phosphorus: 0.03-0.04%, the balance being iron and unavoidable impurities;
the LF refining step comprises the following steps: using LF single refining, the soft blowing time is not less than 15 minutes, and the LF treatment period is more than or equal to 20 min;
the continuous casting step comprises: the pouring is protected in the whole process during continuous casting, the liquid level fluctuation and superheat degree of molten steel are kept stable, and a casting blank with stable quality is obtained;
slowly cooling a casting blank: the temperature of slow cooling entering the pit is more than or equal to 600 ℃, and the temperature of leaving the pit is less than or equal to 200 ℃;
the heating comprises a preheating section, a heating section and a heating section: the temperature of the preheating section is less than or equal to 700 ℃, and the time of the preheating section is more than or equal to 125 minutes; the heating section comprises a heating section and a heating section, the temperature of the heating section is 1140-1160 ℃, the temperature of the heating section is 1100-1180 ℃, and the air-fuel ratio is set as follows: the residual oxygen concentration of the flue gas is controlled to be 1% -1.6%, and the air excess coefficient in the first period is controlled to be 0.85-0.95;
the rolling comprises rough rolling, finish rolling and final rolling, wherein the start rolling temperature of the finish rolling is 1000-1070 ℃, and the final rolling temperature range is 900-930 ℃;
annealing temperature after hot rolling is 1000-1050 ℃, and heat preservation time is 10-20 s;
annealing temperature after cold rolling is 1000-1050 ℃, and heat preservation time is 10-20 s;
and the cooling step after rolling adopts an ultra-fast cooling and laminar cooling mode.
2. A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets is characterized by comprising the following steps: in the step of electric furnace steelmaking, the molten steel comprises the following components in percentage by mass: carbon: 0.5 percent; silicon: 0.5 percent; manganese: 0.8 percent; chromium: 0.06 percent; vanadium: 0.08 percent; niobium: 0.06 percent; oxygen: 0.03 percent; nitrogen: 0.05 percent; sulfur: 0.025%; phosphorus: 0.03%, the remainder being iron and unavoidable impurities.
3. A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets is characterized by comprising the following steps: in the LF refining step, the soft blowing time is 20 minutes, and the LF treatment period is 40 min.
4. A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets is characterized by comprising the following steps: in the heating step, the heating period time is the heating period time plus the heating period time, and the heating period time is controlled to be 100-130 minutes.
5. A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets is characterized by comprising the following steps: in the heating step, the concentration of residual oxygen in the flue gas is controlled to be 1.5-1.6%, and the air excess coefficient in the first period is controlled to be 0.90-0.95.
6. A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets is characterized by comprising the following steps: the annealing temperature after hot rolling is 1020 ℃, and the heat preservation time is 15 s.
7. A production method for improving the surface quality of Nb-containing non-tempered steel continuous casting square billets is characterized by comprising the following steps: the annealing temperature after cold rolling is 1030 ℃, and the heat preservation time is 120 s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210410194.7A CN114686752A (en) | 2022-04-19 | 2022-04-19 | Production method for improving surface quality of Nb-containing non-tempered steel continuous casting square billet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210410194.7A CN114686752A (en) | 2022-04-19 | 2022-04-19 | Production method for improving surface quality of Nb-containing non-tempered steel continuous casting square billet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114686752A true CN114686752A (en) | 2022-07-01 |
Family
ID=82143029
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210410194.7A Pending CN114686752A (en) | 2022-04-19 | 2022-04-19 | Production method for improving surface quality of Nb-containing non-tempered steel continuous casting square billet |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114686752A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112718866A (en) * | 2020-12-15 | 2021-04-30 | 宝钢特钢韶关有限公司 | Manufacturing method for improving surface quality of nitrogen-added steel 18CrNiMo7-6 |
| CN113122776A (en) * | 2021-04-21 | 2021-07-16 | 江苏永钢集团有限公司 | High-strength high-toughness medium-and large-diameter non-quenched and tempered steel for direct cutting and production process thereof |
| CN114107814A (en) * | 2021-11-22 | 2022-03-01 | 山东钢铁集团日照有限公司 | 380 MPa-grade thick-specification wheel steel with high surface quality and production method thereof |
-
2022
- 2022-04-19 CN CN202210410194.7A patent/CN114686752A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112718866A (en) * | 2020-12-15 | 2021-04-30 | 宝钢特钢韶关有限公司 | Manufacturing method for improving surface quality of nitrogen-added steel 18CrNiMo7-6 |
| CN113122776A (en) * | 2021-04-21 | 2021-07-16 | 江苏永钢集团有限公司 | High-strength high-toughness medium-and large-diameter non-quenched and tempered steel for direct cutting and production process thereof |
| CN114107814A (en) * | 2021-11-22 | 2022-03-01 | 山东钢铁集团日照有限公司 | 380 MPa-grade thick-specification wheel steel with high surface quality and production method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP4130316A1 (en) | Pre-hardened mirror mold steel plate and manufacturing method therefor | |
| CN111378896B (en) | High-strength weather-resistant steel plate for building bridge and manufacturing method thereof | |
| CN112981239B (en) | Quenched and tempered low-carbon alloy steel and manufacturing method thereof | |
| CN102899460A (en) | Heat treatment method for martensitic stainless steel forging module | |
| CN113637917A (en) | 690 MPa-level ultrahigh-strength extra-thick ship plate steel with excellent low-temperature impact performance and production method thereof | |
| CN112981232B (en) | 12Cr2Mo1VR steel plate with low compression ratio and high flaw detection quality requirement for continuous casting billet finished product and production process thereof | |
| CN114480962B (en) | Steel for 620 MPa-grade coal mine hydraulic support and manufacturing method thereof | |
| CN111549273B (en) | Method for efficiently producing high-quality 590 MPa-grade cold-rolled dual-phase steel | |
| CN111041329B (en) | High-strength high-toughness steel plate for ocean engineering and production method thereof | |
| CN110724875B (en) | Steel plate for railway and manufacturing method for improving yield strength of steel plate | |
| CN110284061B (en) | High-temperature deformation resistant 75Cr1 saw blade steel and production process thereof | |
| CN114752851B (en) | Low-crack-sensitivity steel plate with 960 MPa-level yield strength and manufacturing method thereof | |
| CN114875331B (en) | 610 MPa-grade thick steel plate with excellent core fatigue performance and production method thereof | |
| CN106676418A (en) | Atmosphere corrosion resisting profile steel liquid containing niobium and nitrogen, atmosphere corrosion resisting profile steel and production method of atmosphere corrosion resisting profile steel | |
| CN114686752A (en) | Production method for improving surface quality of Nb-containing non-tempered steel continuous casting square billet | |
| CN115896598A (en) | Production method of high-toughness F690 super-thick steel plate | |
| CN111020362B (en) | Nodular cast iron edging roll suitable for universal mill and manufacturing method thereof | |
| CN114231826A (en) | Production method of Q420qE bridge structural steel plate | |
| CN115747658B (en) | Production method of high-toughness F500 super-thick steel plate | |
| CN115927809B (en) | Production method of high-toughness F550 super-thick steel plate | |
| CN114836683B (en) | High-strength high-toughness low-yield-ratio pipeline steel plate suitable for wet hydrogen sulfide environment and manufacturing method thereof | |
| CN114774804B (en) | 600 HB-grade hot-rolled low-cost wear-resistant steel plate and manufacturing method thereof | |
| CN114086051B (en) | High-strength high-toughness easily-welded nano steel with thickness of 60-120 mm and thickness of 850MPa and preparation method thereof | |
| CN115961129B (en) | Process for improving low-temperature impact performance of high-strength welding structural steel | |
| CN115386802B (en) | Non-quenched and tempered steel for 10.9-grade large-specification wind power bolts and production method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20220701 |
|
| RJ01 | Rejection of invention patent application after publication |