CN113042545B - Generation control method of disc-screw iron scale with layered structure - Google Patents
Generation control method of disc-screw iron scale with layered structure Download PDFInfo
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- CN113042545B CN113042545B CN202110268802.0A CN202110268802A CN113042545B CN 113042545 B CN113042545 B CN 113042545B CN 202110268802 A CN202110268802 A CN 202110268802A CN 113042545 B CN113042545 B CN 113042545B
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 99
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000005096 rolling process Methods 0.000 claims abstract description 87
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 40
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 34
- 239000010959 steel Substances 0.000 claims abstract description 34
- 238000001816 cooling Methods 0.000 claims abstract description 33
- 238000010438 heat treatment Methods 0.000 claims abstract description 25
- 238000009987 spinning Methods 0.000 claims abstract description 17
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims abstract description 15
- 238000004925 denaturation Methods 0.000 claims abstract description 6
- 230000036425 denaturation Effects 0.000 claims abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 23
- 230000001172 regenerating effect Effects 0.000 claims description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 5
- 238000002791 soaking Methods 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 4
- 230000002035 prolonged effect Effects 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 239000000758 substrate Substances 0.000 abstract description 7
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 abstract 1
- 238000004321 preservation Methods 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 18
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 10
- 241000237858 Gastropoda Species 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 8
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 7
- 239000010931 gold Substances 0.000 description 7
- 229910052737 gold Inorganic materials 0.000 description 7
- 230000003647 oxidation Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 230000006378 damage Effects 0.000 description 5
- 239000000498 cooling water Substances 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 230000032798 delamination Effects 0.000 description 3
- 230000002265 prevention Effects 0.000 description 3
- 241001391944 Commicarpus scandens Species 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
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- 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
-
- 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
- B21B37/46—Roll speed or drive motor control
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B41/00—Guiding, conveying, or accumulating easily-flexible work, e.g. wire, sheet metal bands, in loops or curves; Loop lifters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/004—Heating the product
-
- 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
- C22C38/06—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
- C22C38/18—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
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- 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
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- 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
Abstract
The invention belongs to the technical field of steel rolling, and particularly relates to a generation control method of a spiral iron scale with a layered structure. Heating a billet, and performing rough, medium and pre-finish rolling deformation respectively; controlling the temperature of the finishing mill and the mini mill, and rolling at the mini mill rolling speed; controlling the spinning temperature, turning off the first stelmor fan, turning on the 2 nd to 9 th fans, opening all air cooling line heat preservation covers, prolonging the generation and denaturation time of iron scale at the 950-1000 ℃ temperature section of the spiral shell, and controlling the temperature of the last fan and the speed of each section of the stelmor roller way. The method ensures the mechanical property of the spiral shell, improves the thickness of ferric oxide on the surface of the spiral shell, and has a layered structure of outer Fe layer3O4Layer, inner FeO layer, Fe3O4The total thickness ratio of the layer to the iron scale is 0.28-0.32, the substrate has good adhesion, is not easy to fall off, is continuously and uniformly distributed, and ensures the appearance quality, the service life and the reliability.
Description
Technical Field
The invention belongs to the technical field of steel rolling, and particularly relates to a generation control method of a disc spiral scale with a layered structure, in particular to a method for improving a disc spiral HRB400 scale generation structure through a controlled rolling and controlled cooling production process based on a high-speed disc spiral production line.
Background
The corrosion of high-thread steel bars is a technical problem which is difficult to overcome, and particularly, the phenomenon is commonly existed in the thread steel bars produced by adopting the processes of water passing between rolling and controlled cooling after rolling. The premature destruction of reinforced concrete structures caused by corrosion of the rebar has become a common concern in countries around the world.
The rusting of the steel at normal temperature is the result of oxidation, which can be seen everywhere in real life, and the oxidation speed is very slow in the normal temperature environment, and a thin layer of iron scale can be generated on the surface of the steel when the temperature reaches 200-300 ℃. The oxidation speed is increased along with the continuous increase of the temperature, when the temperature reaches above 950 ℃, the oxidation starts to be vigorously carried out, and when the temperature reaches 1300 ℃, the iron scale starts to melt, and the oxidation speed is more vigorous. The oxidation process being an oxidising gas (O)2、CO2、H2O、SO2Etc.) to chemically react with the surface iron of the steel.
The corrosion of the twisted steel always starts from the transverse rib, the longitudinal rib or the shear fracture and gradually covers the whole surface of the steel. The formation of the scale on the surface of the deformed steel bar is uneven in the length direction, and the specific surface area is large, so that the chemical and electrochemical reactions can be accelerated. FeO has good processing stripping property and substrate adherence, Fe3O4Good compactness and better protection, Fe2O3Is a component of common rust and is easy to further oxidize with water and oxygen in the air to accelerate the rust area and depth of metal, so that the Fe needs to be controlled as much as possible2O3And (4) generating a layer. In order to improve the anti-corrosion capability of the twisted steel produced by adopting the process of water penetration between rolling rooms and controlled cooling after rolling, the rolling process and the controlled cooling process are explored and optimized from the aspects of the overall thickness, the layered structure, the substrate adherence, the continuity and the uniformity of the surface iron oxide scale. The surface oxidized iron sheet with good structure of the twisted steel can greatly improve the service life and reliability of the twisted steel in the processes of outdoor storage, transportation and use. Therefore, a method for controlling the generation of the scale of the disc screw HRB400 with a special structure is needed.
Disclosure of Invention
The invention aims to provide a rolling and cooling control method capable of controlling a disc screw HRB400 iron scale generation structure, which is characterized in that a special surface iron oxide layered structure is obtained by adopting a mini rolling mill high-temperature high-speed rolling control mode, a post-rolling water tank control spinning temperature and a special stelmor cooling control mode, the thickness of the iron scale of the structure reaches 10-20 mu m, and the layered structure is an outer layer of 3-7 mu mFe3O4The layer and the inner layer are 7-15 mu m FeO layers and Fe3O4The ratio of the thickness of the layer to the total thickness of the iron scale is controlled to be 0.28-0.32, the substrate has good adherence, is not easy to fall off and is continuously and uniformly distributed, the rust-resisting period of the spiral shell during outdoor storage and transportation can be ensured to be more than 45 days in rainy days, and the appearance quality, the service life and the reliability are ensured.
In order to achieve the technical purpose, the invention provides a method for controlling the generation of HRB400 scale on a disc screw with a special structure, which comprises the following specific process steps of billet heating, rolling control, spinning and looping, and controlled cooling after rolling:
(1) heating the steel billet in a regenerative heating furnace at the temperature of 730-1220 ℃ for 150-200 min;
(2) after the billet is taken out of the heating furnace, respectively carrying out rough, middle and pre-finish rolling deformation at 910-1080 ℃;
(3) controlling the temperature of the steel billet reaching the finishing mill to be 900-940 ℃ by adjusting the water flow of the water tank;
(4) controlling the temperature of the steel billet reaching the mini rolling mill to be 965-1000 ℃ and the rolling speed of the mini rolling mill to be 35-95 m/s by adjusting the water flow of the water tank;
(5) after rolling, controlling the spinning temperature to 955-1005 ℃ by adjusting the flow of a water tank;
(6) by closing the first stelmor fan, starting the 2 nd to 9 th stelmor fans backwards and opening all the stelmor air-cooling line heat-insulating covers, the generation and modification time of the iron scale of the disc screw HRB400 in the high-temperature section at the temperature of more than 950 ℃ is prolonged as much as possible, the temperature of the last coil screw of the last stelmor fan is ensured to be rapidly reduced to 590 to 630 ℃, the speed of each section of the stelmor roller way is controlled to be 45 to 85m/min, and the speed of the front stelmor roller is less than or equal to 50 m/min.
Further, the steel blank in the step (1) is heated for 45-60 min in a first heating section of a regenerative heating furnace at the temperature of 730-850 ℃, for 45-60 min in a second heating section at the temperature of 950-1050 ℃, and for 60-80 min in a soaking section at the temperature of 1030-1220 ℃.
And (3) after the billet in the step (2) is taken out of the heating furnace, removing the scale on the surface of the billet by starting high-pressure water of 14MPa, wherein the initial rolling temperature of the billet is 910-1080 ℃.
Further, the billet in the step (3) is cooled by opening the cooling water between the racks, so that the rolling temperature of the finishing mill is 900-940 ℃, the high-temperature oxidation temperature atmosphere in the rolling process is ensured, and the rolling temperature of the next mini rolling mill can be conveniently controlled.
Further, the temperature reaching the mini rolling mill is controlled to be 965-1000 ℃, the rolling speed of the mini rolling mill is 35-95 m/s, the high-temperature oxide scale generating atmosphere is controlled, and the denaturation time of the oxide scales at the high-temperature section is prolonged by properly reducing the rolling speed.
Further, step (6) turns off station 1 by 2 × 105The stelmor fan of W further prolongs the generation and denaturation time of the iron scale at the high-temperature section; 2 nd to 9 th stations are started with power of 2 multiplied by 105W Stelmo fan with air quantity opening of 60 to100 percent, setting the speed of each stelmor roller way to be 45-85 m/min, setting the speed of the stelmor rollers in the front three sections to be less than or equal to 50m/min, opening all stelmor air-cooling line heat-preserving covers, reducing the temperature of the spiral shell to 590-630 ℃ after the spiral shell passes through a No. 9 fan, and ensuring that the indexes such as mechanical property and the like are qualified through air cooling and air cooling.
The disc snail HRB400 comprises the following chemical components in percentage by mass: 0.21 to 0.25%, Si: 0.30-0.80%, Mn: 1.25-1.60%, P is less than or equal to 0.045%, S is less than or equal to 0.045%, and Al: 0.000 to 0.005%, Ti: 0.000-0.015%, N: 0.0060-0.0120%, Ceq: 0.45 to 0.54 percent of iron and the balance of inevitable impurities.
The yield strength of the obtained disc spiral HRB400 is 410-470 MPa, other indexes meet the requirements of GB/T1499.2-2018, the thickness of iron oxide on the surface of the disc spiral HRB400 is increased to 10-20 mu m, and the layered structure is that the outer layer is 3-7 mu m Fe3O4The layer and the inner layer are FeO layers of 7-15 mu m and Fe3O4The ratio of the layer thickness to the total thickness of the iron scale is controlled to be 0.28-0.32, the matrix has good adherence, is not easy to fall off and is continuously and uniformly distributed, the anti-rust period of the spiral shell during outdoor storage and transportation can be ensured to be more than 45 days in rainy days, and the appearance quality, the service life and the reliability are ensured.
The invention creates proper process conditions for generating reasonable thickness and structure of the HRB400 scale of the disc screw by adopting a mini rolling mill high-temperature high-speed controlled rolling, a post-rolling water tank controlled spinning temperature and a special Stelmor controlled cooling mode. High-temperature rolling is adopted before a mini rolling mill, high-temperature spinning is realized through water tank adjustment after the mini rolling mill, and the high-temperature oxidation reaction time for generating iron scales on the surface of the disc screw HRB400 is ensured; the stelmor fan moves backwards to be opened, the specific roller speed and the fan air volume are controlled to ensure the specific cooling rate, and a longer high-temperature high-pressure environment is created for the denaturation reaction of the iron scale on the surface of the disc screw HRB 400.
According to the invention, a mini rolling mill is adopted to produce finished products, the rolling speed is controlled to be 35-95 m/s, taking phi 8mm as an example, the rolling speed of the finished products produced by the traditional finishing mill is only 28m/s, the rolling speed of the mini rolling mill can be controlled to be 80m/s, and the mini rolling mill has more advantages in productivity exertion and greater economic benefits. The thickness of iron oxide is improved by simply depending on high-temperature speed reduction rolling of a finished product produced by a traditional finishing mill, a layered structure of the iron oxide is not concerned, and the disc bolt HRB400 which is simply pursuing to improve the thickness of the iron oxide has large brittleness and is easy to fall off due to overlarge thickness or unreasonable structure of the iron oxide in the outdoor stacking, transportation and storage processes, the rust-resisting period generally does not exceed 20 days, the rainy weather generally does not exceed 7 days, and the rust-resisting period of the disc bolt HRB400 with the iron oxide scale with the special structure can still be ensured to be more than 45 days in the rainy weather.
On the basis of high-temperature high-speed rolling and spinning temperature spinning of a mini rolling mill, a special stelmor cooling control mode is adopted, a stelmor fan moves backwards to be started, the specific roller speed and the fan air volume are controlled to ensure the specific cooling rate, a longer high-temperature high-pressure environment is created for the denaturation reaction of iron scale on the surface of the disc screw HRB400, and the disc screw HRB400 has sufficient time and environmental conditions to generate Fe3O4The specific value of the layer thickness to the total thickness of the iron scale is controlled to be 0.28-0.32, and all Stelmor air cooling lines are opened to realize air cooling and air cooling, so that the indexes such as mechanical properties can be guaranteed to be qualified.
Drawings
FIG. 1 is a scale texture map of HRB400 spiral shells produced in example 1.
Fig. 2 is a scale texture map of HRB400 disc snails produced in example 2.
Fig. 3 is a scale texture map of HRB400 disc snails produced in example 3.
Fig. 4 is a scale texture map of HRB400 disc snails produced in comparative example 1.
Fig. 5 is a scale texture map of HRB400 disc snails produced in comparative example 2.
Fig. 6 is a scale texture map of HRB400 disc snails produced in comparative example 3.
Fig. 7 is a scale texture map of HRB400 disc snails produced in comparative example 4.
FIG. 8 is a surface state diagram of HRB400 spiral shell produced in example 1 when stacked outdoors in open air for 45 days.
FIG. 9 is a surface state diagram of an HRB400 spiral shell produced in comparative example 1 when stacked outdoors in the open air for 7 days.
Detailed Description
The invention combines the high-speed disc screw controlled rolling and controlled cooling technology to 160 multiplied by 160mm2The production implementation of the hot-rolled disc screw HRB400 with finished specifications of phi 6.0mm, phi 8.0mm and phi 12.0mm is explained by the continuous casting billet with the section.
Example 1 (Phi 6.0mm spiral HRB400)
1. Heating of steel billets
Rolling blank component C: 0.23%, Si: 0.45%, Mn: 1.38%, P: 0.025%, S: 0.020%, Al: 0.003%, Ti: 0.008%, N: 0.0088%, Ceq: 0.46% and the balance iron and inevitable impurities.
A billet with a section of 160mm multiplied by 160mm is heated for 50min in a regenerative heating furnace in a temperature environment of 750-850 ℃ for the first section, for 50min in a temperature environment of 950-1050 ℃ for the second section, and for 65min in a temperature environment of 1030-1100 ℃ for the soaking section.
2. Controlled rolling
After the steel billet is taken out of the heating furnace, removing the iron scale on the surface of the steel billet by starting high-pressure water with the pressure of 14MPa, wherein the initial rolling temperature of the steel billet is 1030-1055 ℃; the billet passes through cooling water between the opening racks, so that the rolling temperature of the finishing mill is 940 ℃, the temperature reaching the mini rolling mill is controlled at 1000 ℃, and the rolling speed of the mini rolling mill is 95 m/s.
3. Laying-out loop-forming
After finishing rolling, the spinning temperature of the wire rod is controlled at 1005 ℃ by adjusting the flow of the water tank.
4. Controlled cooling after rolling
After spinning and looping, the wire rod is arranged on a stelmor roller way, and the power of the wire rod is 2 multiplied by 10 by turning off a 1 st stelmor fan and turning on 2 nd to 9 th stelmor fans5W stelmor fan with the air flow opening of 2-3 100%, 4-8 70% and 9-60%, the roller speed of each stelmor section is 46m/min, 48m/min, 50m/min, 55m/min, 61m/min, 65m/min, 70m/min, 75m/min, 85m/min, 75m/min, 69m/min and 56m/min, all stelmor air-cooled line heat-insulating covers are opened, the lap joint temperature of the spiral passing through the No. 9 fan is reduced to 615 ℃, and the non-lap joint temperature is reducedWhen the temperature is 595 ℃, the indexes of mechanical property and the like are qualified by air cooling and air cooling, and the yield strength is 438MPa, the tensile strength is 651MPa, and the elongation after fracture is 29.5 percent.
FIG. 1 is a photograph of the iron scale gold at the edge of the disc spiral HRB400 produced in example 1. As can be seen from figure 1, the total thickness of the scale at the edge of the disc spiral HRB400 reaches 12.53 mu m, the delamination is obvious, and the outer layer is 3.68 mu mFe3O4Layer, inner layer is 8.85 mu m FeO layer, Fe3O4The ratio of the thickness of the layer to the total thickness of the iron scale is 0.29, the thickness is uniform and moderate, the iron scale is continuous and free of damage, and the base body adhesion is good.
Example 2 (Phi 8.0mm spiral HRB400)
1. Heating of steel billets
Rolling blank component C: 0.24%, Si: 0.46%, Mn: 1.40%, P: 0.025%, S: 0.020%, Al: 0.005%, Ti: 0.008%, N: 0.0085%, Ceq: 0.47%, and the balance of iron and inevitable impurities.
A billet with a section of 160mm multiplied by 160mm is heated for 50min in a regenerative heating furnace in a temperature environment of 750-850 ℃ for the first section, for 50min in a temperature environment of 950-1050 ℃ for the second section, and for 65min in a temperature environment of 1030-1100 ℃ for the soaking section.
2. Controlled rolling
After the steel billet is taken out of the heating furnace, removing the iron scale on the surface of the steel billet by starting high-pressure water with the pressure of 14MPa, wherein the initial rolling temperature of the steel billet is 1030-1055 ℃; the billet passes through cooling water between the racks, so that the rolling temperature of the finishing mill is 940 ℃, the temperature reaching the mini rolling mill is controlled to be 980 ℃, and the rolling speed of the mini rolling mill is 80 m/s.
3. Laying-out loop-forming
After finishing rolling, the spinning temperature of the wire rod is controlled at 1000 ℃ by adjusting the flow of the water tank.
4. Controlled cooling after rolling
After spinning and looping, the wire rod is arranged on a stelmor roller way, and the power of the wire rod is 2 multiplied by 10 by turning off a 1 st stelmor fan and turning on 2 nd to 9 th stelmor fans5W Stelmor fans with the air volume opening degree of 2-4 stations of 100 percent, 5-8 stations of 80 percent and 9 th station of 70 percent, and the roller speed of each section of Stelmor is 45 m-min, 48m/min, 50m/min, 60m/min, 62m/min, 64m/min, 65m/min, 66m/min, 68m/min, 70m/min, 64m/min and 54m/min, opening all Stelmor air-cooled line heat-insulating covers, reducing the temperature of a lap joint point of a spiral shell to 620 ℃ after the spiral shell passes through a No. 9 fan, reducing the temperature of a non-lap joint point to 596 ℃, ensuring that indexes such as mechanical properties are qualified by air cooling and air cooling, and ensuring that the yield strength is 440MPa, the tensile strength is 656MPa and the elongation after fracture is 30.0%.
FIG. 2 is a photograph of the iron scale gold at the edge of the disc spiral HRB400 produced in example 2. As can be seen from figure 2, the total thickness of the scale at the edge of the disc spiral HRB400 reaches 15.43 mu m, the delamination is obvious, and the outer layer is 5 mu mFe3O4Layer, inner layer is 10.43 mu m FeO layer, Fe3O4The ratio of the thickness of the layer to the total thickness of the iron scale is 0.32, the thickness is uniform and moderate, the iron scale is continuous and free of damage, and the base body adhesion is good.
Example 3 (phi 12.0mm spiral HRB400)
1. Heating of steel billets
Rolling blank component C: 0.22%, Si: 0.47%, Mn: 1.37%, P: 0.025%, S: 0.025%, Al: 0.002%, Ti: 0.005%, N: 0.0080%, Ceq: 0.45 percent.
A billet with a section of 160mm multiplied by 160mm is heated for 50min in a regenerative heating furnace in a temperature environment of 750-850 ℃ for the first section, for 50min in a temperature environment of 950-1050 ℃ for the second section, and for 65min in a temperature environment of 1030-1100 ℃ for the soaking section.
2. Controlled rolling
After the steel billet is taken out of the heating furnace, removing the iron scale on the surface of the steel billet by starting high-pressure water with the pressure of 14MPa, wherein the initial rolling temperature of the steel billet is 1030-1055 ℃; the billet passes through cooling water between the opening racks, so that the rolling temperature of the finishing mill is 940 ℃, the temperature reaching the mini rolling mill is controlled at 950 ℃, and the rolling speed of the mini rolling mill is 35 m/s.
3. Laying-out loop-forming
After finishing rolling, the spinning temperature of the wire rod is controlled at 960 ℃ by adjusting the flow of the water tank.
4. Controlled cooling after rolling
After spinning and looping, the wire rod is on the stelmor roller table by closing the 1 stThe power of the 2 nd to 9 th desk is 2 multiplied by 10 when the Tesla molar fan is started5The W stelmor fan has the air volume opening of 100 percent of the 2 nd to 4 th fan, 90 percent of the 5 th to 8 th fan and 80 percent of the 9 th fan, the roller speeds of all the stelmor sections are respectively 45m/min, 46m/min, 50m/min, 59m/min, 62m/min, 64m/min, 66m/min, 69m/min, 71m/min, 66m/min, 65m/min and 55m/min, all the stelmor air-cooled line heat-insulating covers are opened, the lap joint temperature of a disc screw passing through the No. 9 fan is reduced to 628 ℃, the non-lap joint temperature is reduced to 598 ℃, the mechanical property and other indexes of the disc screw can be guaranteed to be qualified through air cooling and air cooling, the yield strength is 444MPa, the tensile strength is 653MPa, and the elongation after-break is 27.5 percent.
FIG. 3 is a photograph of the iron scale gold at the edge of the disc spiral HRB400 produced in example 3. As can be seen from FIG. 3, the total thickness of the scale at the edge of the disc spiral HRB400 reaches 15.62 μm, the delamination is obvious, and the outer layer is 4.56 μmFe3O4Layer, inner layer is 11.06 mu m FeO layer, Fe3O4The ratio of the thickness of the layer to the total thickness of the iron scale is 0.29, the thickness is uniform and moderate, the iron scale is continuous and free of damage, and the base body adhesion is good.
COMPARATIVE EXAMPLE 1 (Phi 6.0mm spiral HRB400)
Comparative example 1 differs from example 1 mainly in that: the temperature of 1000 ℃ when the billet in the step 2 of the example 1 reaches a mini rolling mill is replaced by 920 ℃, the spinning temperature of a wire rod in the step 3 is replaced by 865 ℃ from 1005 ℃, the fan opening mode in the step 4 is replaced by turning off the 1 st fan and turning on the 2 nd to 9 th Steyr fans, the temperature of the coil screw is reduced to 590 ℃ to 630 ℃ after the coil screw passes through the No. 8 fan, and other conditions are the same as the example 1.
FIG. 4 is a photograph of the edge scale gold phase of HRB400 for the disk spiral produced in comparative example 1. As can be seen from FIG. 4, the total thickness of the scale at the edge of the disc screw HRB400 is only 2.52 μm, the crushing is discontinuous and no obvious layering exists, the substrate has poor adhesion, the substrate is easy to fall off, and the antirust effect is poor.
COMPARATIVE EXAMPLE 2 (Phi 8.0mm spiral HRB400)
Comparative example 2 compared to example 2, the main differences are: the stelmor roller speeds of the first three sections of step 4 of the example 2 are respectively 45m/min, 48m/min and 50m/min and are replaced by 50m/min, 53m/min and 55m/min, and other conditions are the same as the example 2.
FIG. 5 is a photograph of the edge scale gold phase of HRB400 for the disk spiral produced in comparative example 2. As can be seen from FIG. 5, the total thickness of the scale at the edge of the disc spiral HRB400 reaches 7.45 μm, and the outer layer is 3.23 μmFe3O4Layer of Fe3O4The ratio of the thickness of the layer to the total thickness of the iron scale is 0.43, the layering is obvious, but the layer is discontinuous and is easy to break and fall off, and the antirust effect is poor.
COMPARATIVE EXAMPLE 3 (Phi 8.0mm spiral HRB400)
Comparative example 3 compared to example 2, the main differences are: the stelmor roller speeds of the first three sections of step 4 of the example 2 are respectively 45m/min, 48m/min and 50m/min and are replaced by 40m/min, 41m/min and 44m/min, and other conditions are the same as the example 2.
FIG. 6 is a photograph of the edge scale gold phase of HRB400 for the disk spiral produced in comparative example 3. As can be seen from FIG. 6, the total thickness of the scale at the edge of the disc spiral HRB400 reaches 21.27 μm, and the outer layer is locally 3.56 μmFe3O4Layer of Fe3O4The ratio of the thickness of the layer to the total thickness of the iron scale is 0.17, the layering is not obvious, the iron scale is easy to break and fall off, and the antirust effect is poor.
COMPARATIVE EXAMPLE 4 (Phi 12.0mm spiral HRB400)
Comparative example 4 compared to example 3, the main differences are: the step 2 of the example 3 is that the mini rolling mill rolling speed is reduced from 35m/s to 28m/s, and other conditions are the same as the example 1.
FIG. 7 is a photograph of the edge scale gold phase of HRB400 for the disk spiral produced in comparative example 4. As can be seen from FIG. 7, the total thickness of the scale at the edge of the disc spiral HRB400 reaches 16.59 μm, and the outer layer is 5.65 μmFe3O4Layer of Fe3O4The ratio of the layer thickness to the total thickness of the iron scale is 0.34, the layering is obvious, the thickness is uniform, but because of Fe3O4The ratio of the thickness of the layer to the total thickness of the iron scale is more than 0.32, the iron scale has larger brittleness and is easy to damage and fall off, and the good protection and rust prevention effect cannot be achieved.
Fig. 8 shows the surface state of the HRB400 snails produced in example 1 after being stacked outdoors in the open air for 45 days, which has a good rust prevention effect, and is continuously tracked for 45 days, wherein 30 days are rainy days, no obvious rust is observed on the surface of the snails, and the iron oxide scale is bright and complete and has no shedding.
Fig. 9 shows the surface state of the HRB400 whelk produced in comparative example 1 after being stacked outdoors in the open air for only 7 days, which is poor in rust prevention effect and continuously tracked for 7 days, wherein 4 days are rainy days, a large area of rust appears on the surface of the whelk, and the scale becomes reddish brown and a large area of shedding occurs.
The invention adopts a controlled rolling and controlled cooling process, so that the thickness of iron oxide on the surface of the disc spiral HRB400 can be controlled to be 10-20 mu m, and the outer layer is 3-7 mu m Fe3O4The inner layer is a 7-15 mu m FeO layer, is continuously and uniformly distributed, has good substrate adherence, can greatly improve the rust resistance of the spiral HRB400 under different weather conditions in the outdoor stacking, using and warehousing processes, improves the service life and the reliability of the spiral HRB, has the yield strength of 410-470 MPa, and meets the requirements of GB/T1499.2-2018 for other indexes. In addition, high rolling speed can be guaranteed through high-temperature rolling, and the production capacity of equipment can be fully exerted to a certain extent.
The raw materials and equipment used in the invention are common raw materials and equipment in the field if not specified; the methods used in the present invention are conventional in the art unless otherwise specified. The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all modifications of the above embodiments made according to the technical spirit of the present invention are included in the scope of the present invention.
Claims (6)
1. A generation control method of a disc spiral HRB400 iron scale with a layered structure is characterized by comprising the following steps: the method comprises the following steps: heating a steel billet, rolling under control, spinning and looping, and cooling under control after rolling, and the method comprises the following specific steps:
(1) heating the steel billet in a regenerative heating furnace at the temperature of 730-1220 ℃ for 150-200 min;
(2) after the billet is taken out of the heating furnace, respectively carrying out rough, middle and pre-finish rolling deformation at 910-1080 ℃;
(3) controlling the temperature of the steel billet reaching the finishing mill to be 900-940 ℃ by adjusting the water flow of the water tank;
(4) controlling the temperature of the steel billet reaching the mini rolling mill to be 965-1000 ℃ and the rolling speed of the mini rolling mill to be 35-95 m/s by adjusting the water flow of the water tank;
(5) after rolling, controlling the spinning temperature to 955-1005 ℃ by adjusting the flow of a water tank;
(6) by closing the first stelmor fan, starting the 2 nd to 9 th stelmor fans backwards and opening all the stelmor air-cooling line heat-insulating covers, the generation and denaturation time of iron scale of the disc screw HRB400 in a high-temperature section at the temperature of more than 950 ℃ is prolonged, and meanwhile, the temperature of the last coil screw of the last stelmor fan is ensured to be rapidly reduced to 590-630 ℃.
2. The generation control method of a disc spiral HRB400 iron scale with a layered structure as claimed in claim 1, characterized in that: the spiral shell comprises the following chemical components in percentage by mass: 0.21 to 0.25%, Si: 0.30-0.80%, Mn: 1.25-1.60%, P is less than or equal to 0.045%, S is less than or equal to 0.045%, and Al: 0.000 to 0.005%, Ti: 0.000-0.015%, N: 0.0060-0.0120%, Ceq: 0.45 to 0.54 percent of iron and the balance of inevitable impurities.
3. The generation control method of a disc spiral HRB400 iron scale with a layered structure as claimed in claim 1, characterized in that: the steel billet in the step (1) is heated for 45-60 min in a temperature environment of 730-850 ℃ in a first heating section of a regenerative heating furnace, for 45-60 min in a temperature environment of 950-1050 ℃ in a second heating section, and for 60-80 min in a temperature environment of 1030-1220 ℃ in a soaking section.
4. The generation control method of a disc spiral HRB400 iron scale with a layered structure as claimed in claim 1, characterized in that: step (6) close the 1 st station 2X 105W stelmor fan, 2 nd to 9 th fans are started with power of 2 x 105W is the stelmor fan, and the air volume opening is 60-100%.
5. The generation control method of a disc spiral HRB400 iron scale with a layered structure as claimed in claim 1, characterized in that: and (6) setting the speed of each stelmor roller way to be 45-85 m/min, setting the speed of the stelmor rollers in the first three sections to be less than or equal to 50m/min, and opening all stelmor air-cooling line heat-insulating covers.
6. A disk spiral HRB400 having a layered structure obtained by the method of claim 1, wherein: the thickness of the iron oxide on the surface of the obtained disc spiral HRB400 is 10-20 mu m, and the layered structure is 3-7 mu m Fe on the outer layer3O4A layer, an inner layer is a FeO layer of 7-15 μm, Fe3O4The ratio of the thickness of the layer to the total thickness of the iron scale is controlled to be 0.28-0.32; the yield strength of the disc spiral HRB400 is 410-470 MPa.
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