CN114480945A - Method for producing quenched and tempered wear-resistant steel plate NM400 with thickness less than 30mm by using online waste heat - Google Patents
Method for producing quenched and tempered wear-resistant steel plate NM400 with thickness less than 30mm by using online waste heat Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 84
- 239000010959 steel Substances 0.000 title claims abstract description 84
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 24
- 239000002918 waste heat Substances 0.000 title claims abstract description 15
- 238000000034 method Methods 0.000 claims abstract description 59
- 230000008569 process Effects 0.000 claims abstract description 45
- 238000010438 heat treatment Methods 0.000 claims abstract description 39
- 238000001816 cooling Methods 0.000 claims abstract description 37
- 238000005096 rolling process Methods 0.000 claims abstract description 34
- 238000005496 tempering Methods 0.000 claims abstract description 19
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 17
- 239000000126 substance Substances 0.000 claims abstract description 11
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 9
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 9
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 6
- 239000002893 slag Substances 0.000 claims description 49
- 238000007670 refining Methods 0.000 claims description 34
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 24
- 238000009749 continuous casting Methods 0.000 claims description 19
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- 238000010079 rubber tapping Methods 0.000 claims description 16
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 14
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 14
- 239000004571 lime Substances 0.000 claims description 14
- 229910052742 iron Inorganic materials 0.000 claims description 12
- 238000003723 Smelting Methods 0.000 claims description 10
- 239000010936 titanium Substances 0.000 claims description 10
- 229910052796 boron Inorganic materials 0.000 claims description 9
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 8
- 229910052681 coesite Inorganic materials 0.000 claims description 8
- 229910052906 cristobalite Inorganic materials 0.000 claims description 8
- 239000000377 silicon dioxide Substances 0.000 claims description 8
- 238000010583 slow cooling Methods 0.000 claims description 8
- 229910052682 stishovite Inorganic materials 0.000 claims description 8
- 229910052719 titanium Inorganic materials 0.000 claims description 8
- 229910052905 tridymite Inorganic materials 0.000 claims description 8
- 238000005266 casting Methods 0.000 claims description 7
- 239000003607 modifier Substances 0.000 claims description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 5
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 5
- 239000011575 calcium Substances 0.000 claims description 5
- 229910052791 calcium Inorganic materials 0.000 claims description 5
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 4
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 4
- 229910001309 Ferromolybdenum Inorganic materials 0.000 claims description 4
- 238000005275 alloying Methods 0.000 claims description 4
- 229910052786 argon Inorganic materials 0.000 claims description 4
- 238000007664 blowing Methods 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 238000006477 desulfuration reaction Methods 0.000 claims description 4
- 230000023556 desulfurization Effects 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 4
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 4
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 4
- 230000007246 mechanism Effects 0.000 claims description 4
- 238000002360 preparation method Methods 0.000 claims description 4
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- 238000010791 quenching Methods 0.000 abstract description 11
- 230000000171 quenching effect Effects 0.000 abstract description 11
- 229910001566 austenite Inorganic materials 0.000 abstract description 2
- 238000009847 ladle furnace Methods 0.000 description 7
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- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
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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
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
-
- 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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Abstract
A method for producing a quenched and tempered wear-resistant steel plate NM400 with the thickness of less than 30mm by using online waste heat is characterized in that online quenching is carried out by using the waste heat after rolling on a medium plate production line, and tempering is carried out by using an offline heat treatment furnace, wherein the tempering temperature is 450-plus-500 ℃, and the tempering time is 1.8Tmin (T is the thickness of the steel plate). The method utilizes on-line waste heat quenching to replace the process of quenching the steel plate after the steel plate is heated from room temperature to an austenite region in an off-line heat treatment furnace, thereby greatly reducing the heat treatment cost for producing the quenched and tempered wear-resistant steel plate. By means of the design of chemical components, the martensite structure is obtained by cooling to below 400 ℃ at a cooling rate of 10-15 ℃/s. The NM400 steel grade comprises the following chemical components in percentage by mass: c: 0.22 to 0.26%, Si: 0.4-0.6%, Mn: 1.3-1.55%, P is less than or equal to 0.020%, S is less than or equal to 0.007%, Mo: 0.3-0.45%, Cr: 0.8-0.95%, Al: 0.01-0.035%, 0.001-0.005% of B, less than or equal to 0.04% of Ti, and the balance of Fe and inevitable impurities.
Description
Technical Field
The invention relates to the technical field of wear-resistant steel production, in particular to a method for producing a quenched and tempered wear-resistant steel plate NM400 with the thickness of less than 30mm by using online waste heat.
Background
NM400 is a high-strength wear-resistant steel plate, has quite high mechanical strength, has 3 to 5 times of mechanical properties of common low-alloy steel plates, and can remarkably improve the wear resistance of relevant parts of machinery, thereby prolonging the service life of the machinery and reducing the production cost of enterprises. The steel plate is mainly used for processing and manufacturing wear-resistant wearing parts for mines and various engineering machinery.
The NM400 steel produced by the current industry generally adopts off-line production, namely, after the steel plate is rolled, quenching and tempering are finished in a heat treatment process. The method needs special quenching equipment, is complex in process, high in production cost and high in energy consumption, and is not beneficial to achieving the purposes of energy conservation and emission reduction in the steel industry. In addition, the wear-resistant steel produced by the method has the problem of poor impact deformation resistance, so that a production method which is more environment-friendly and energy-saving and can maintain excellent mechanical properties of the NM400 wear-resistant steel plate is urgently needed.
Disclosure of Invention
The invention discloses a method for producing a quenched and tempered wear-resistant steel plate NM400 with the thickness of less than 30mm by using on-line waste heat, which directly uses the rolled waste heat to finish quenching on line and only finishes tempering in a heat treatment stage so as to realize delivery of a quenched and tempered state and reduce the production cost.
The method for producing the quenched and tempered wear-resistant steel plate NM400 with the thickness of less than 30mm by using online waste heat is characterized by comprising the following steps of: smelting in a converter, refining in an LF (ladle furnace), continuous casting of a plate blank, heating of the plate blank, rolling, cooling, heat treatment, sampling detection, identification and warehousing;
in the converter smelting process, high-quality molten iron subjected to KR desulfurization treatment is added into molten iron fed into a converter, medium-carbon ferromanganese is added into the converter smelting process, the control terminal point P is less than or equal to 0.015 percent, Als is 0.03-0.05 percent, a slag blocking cone and a slag blocking plug are adopted for double-slag-blocking tapping, the slag thickness is less than or equal to 50mm, ferromolybdenum, ferrochrome, steel sand aluminum and lime are added during tapping for deoxidation and alloying, and the tapping temperature is as follows: 1630 and 1680 ℃.
In the LF furnace refining process, a large amount of slag is refined by using a steel slag modifier, refining slag and lime, slag is picked and observed in the refining process, the addition amount of the lime is adjusted according to slag conditions, the white slag is kept for more than or equal to 18min, and the alkalinity is controlled to be 5-7; and feeding a titanium wire, a boron wire and a calcium wire in sequence at the later stage of refining, introducing argon for soft blowing and stirring, and controlling the tapping temperature to 1575-1585 ℃.
The slab continuous casting process is characterized in that the whole process is protected for casting, a water cooling system adopts a weak water cooling mechanism, the cut continuous casting slab enters a slow cooling pit for slow cooling for 48 hours at a drawing speed of 0.8-1.0m/min, and the specification of the continuous casting blank is as follows: the thickness is 220mm, the width is 1240-1580 mm, and the length is 2000-2700 mm; the chemical components and the contents of the continuous casting billet are as follows: c: 0.22 to 0.26%, Si: 0.4-0.6%, Mn: 1.3-1.55%, P is less than or equal to 0.020%, S is less than or equal to 0.007%, Mo: 0.3-0.45%, Cr: 0.8-0.95%, Als: 0.01-0.035%, B0.001-0.005%, Ti less than or equal to 0.04%, and the balance of Fe and inevitable impurities;
in the slab heating process, the heating furnace adopts a three-section type heating system: the heating period is 1000-1100 ℃, the heating period is 1200-1220 ℃, the soaking period is 1180-1200 ℃, and the in-furnace time is 4.5-5.0 h.
The rolling procedure adopts a TMCP (thermal mechanical control processing) process for rolling, wherein the initial rolling temperature of the billet in the first stage is 1120-1150 ℃, the thickness to be cooled is 2-3 times of the thickness of the finished product, the initial rolling temperature in the second stage is 860-930 ℃, and the final rolling temperature is 800-820 ℃; the thickness dimension precision of the steel plate is realized by strictly controlling the service quantity of the rolling rolls, the rolling in the middle service period of the rolls is ensured, and the control range of the precision of the matched rolls is 0-0.4 mm; three secondary high-pressure water descaling and cooling control are adopted and respectively distributed to the second pass after the steel is rotated in the first stage, the first pass is rolled in the second stage, and the last but one third pass is rolled in the last stage, so that the large-thickness iron scale on the surface of the steel plate is effectively eliminated;
in the cooling procedure, water cooling is adopted, and the ratio of the water feeding amount to the water discharging amount is controlled to be about 1: 1.3; the roller speed is 0.8-1.2m/s, the initial cooling temperature is 780-800 ℃, the cooling speed is 10-15 ℃/s, and the final cooling temperature is 350-400 ℃;
the heat treatment process adopts a continuous roller hearth type heat treatment furnace for on-line tempering, and the tempering temperature is as follows: 450 ℃ plus 500 ℃ and the tempering time is 1.8Tmin (T steel plate thickness).
Further, in the LF refining process, the steel slag modifier mainly comprises the following components: al (Al)2O3：15%-25%，Al ：40%-45%，MgO：＜5%，SiO2: less than 5 percent, the steel slag modified preparation comprises the following components in percentage by weight: 1.0-1.3 kg per ton steel.
Further, in the LF refining process, the refining slag mainly comprises the following components: al (Al)2O3：1%-2%，CaO：45%-55%，SiO2：18%-22%，MgO：20-25%，Fe2O3: 0.5 to 1.0 percent, and the addition amount of the refining slag is as follows: 1.8-2.2 kg per ton steel.
The quenched and tempered wear-resistant steel plate NM400 with the thickness of less than 30mm produced by the method comprises the following chemical components in percentage by mass: 0.22 to 0.26%, Si: 0.4-0.6%, Mn: 1.3-1.55%, P is less than or equal to 0.020%, S is less than or equal to 0.007%, Mo: 0.3-0.45%, Cr: 0.8-0.95%, Al: 0.01-0.035%, 0.001-0.005% of B, less than or equal to 0.04% of Ti, and the balance of Fe and inevitable impurities.
The mechanical property parameters of the quenched and tempered wear-resistant steel plate NM400 are as follows: the tensile strength is more than or equal to 1200MPa, the elongation is more than or equal to 13, the Hardness (HV) is more than or equal to 400, and the metallographic structure is tempered martensite.
The invention has the beneficial effects that:
1. the production process flow is simplified. Starting from the characteristics of the material, the production process is scientifically designed, the on-line waste heat after rolling is fully utilized, the composition design, the rolling process design and the cooling process design are fully combined on the basis of the phase change theory, the on-line quenching room-temperature structure is realized to be martensite, the off-line tempering is utilized, the structure in a quenching and tempering state is finally realized, and the performance of the product is met.
2. The production cost is reduced. The on-line quenching is implemented by using the waste heat after rolling, the heat energy of the on-line waste heat is fully utilized, the heat treatment process of off-line heating to an austenite region for quenching is avoided, the energy is saved, and the production cost is reduced.
3. The delivery cycle is shortened. By adopting the method, the delivery cycle of the quenched and tempered wear-resistant steel plate can be shortened by 7-10 days, so that time surplus is created for downstream users; meanwhile, the quenching process in the heat treatment is reduced, the transportation cost of the steel plate in the heat treatment process is reduced, and the production cost is further reduced.
Drawings
FIG. 1 is a metallographic structure picture of a quenched and tempered wear-resistant NM400 steel plate obtained in example 1;
fig. 2 is a metallographic structure picture of the quenched and tempered wear-resistant NM400 steel plate obtained in example 2.
Detailed Description
The invention is further described with reference to the following figures and detailed description.
Example 1
The quenched and tempered wear-resistant steel plate NM400 with the thickness of 30mm comprises the following chemical components in percentage by mass: c: 0.23%, Si: 0.55%, Mn: 1.42%, P: 0.01%, S: 0.004%, Mo: 0.4%, Cr: 0.88%, Al: 0.024%, B:0.0024%, Ti: 0.017% and the balance of Fe and inevitable impurities. As shown in FIG. 1, the metallographic structure of the steel sheet was tempered martensite, and the steel sheet had a uniform grain distribution and no mixed crystals or segregation.
The production method of the quenched and tempered wear-resistant steel plate NM400 with the thickness of 30mm comprises the following steps:
(1) the converter smelting process is characterized in that high-quality molten iron subjected to KR desulphurization treatment is added into molten iron fed into the converter, medium-carbon ferromanganese is added into the converter smelting process, the control end point P is less than or equal to 0.015 percent, Als (acid soluble aluminum) is 0.04 percent, double-slag-stopping tapping is carried out by adopting a slag stopping cone and a slag stopping plug, and slag thickness is as follows: 40mm, adding ferromolybdenum, ferrochromium, steel grit aluminum and lime for deoxidation and alloying during tapping, wherein the tapping temperature is as follows: 1680 deg.C.
(2) An LF furnace refining process, wherein 1.3kg/t steel of a steel slag modifying agent, 2.2kg/t steel of refining slag and lime are adopted for large-slag-quantity slagging refining, slag is picked up and observed in the refining process, the addition of the lime is adjusted according to the slag condition, the white slag is kept for 25min, and the alkalinity is controlled to be 7; and (3) feeding about 50m of titanium wire, about 30m of boron wire and about 70m of calcium wire in sequence at the later stage of refining, introducing argon for soft blowing and stirring, and controlling the tapping temperature at 1575 ℃.
The steel slag modified preparation mainly comprises the following components: al (Al)2O3：15%-25%，Al ：40%-45%，MgO：＜5%，SiO2：＜5%；
The refining slag comprises the following main components: al (Al)2O3：1%-2%，CaO：45%-55%，SiO2：18%-22%，MgO：20-25%，Fe2O3：0.5%-1.0%；
The steel slag modifier, the refining slag and the lime are added to adjust the alkalinity of molten steel in a refining furnace so as to realize the aims of desulfurization, dephosphorization and deoxidation.
(3) A slab continuous casting process, wherein the continuous casting adopts special casting powder (SiO)2：30%-35%，CaO：30%-35%，MgO：2%-5%，Al2O3：4%-8%，Na2O: 8% -14%) and protecting the casting in the whole process, wherein a water cooling system adopts a weak water cooling mechanism, the continuous casting blank enters a slow cooling pit for slow cooling for 48h after being cut, the drawing speed is 0.8m/min, and the specification of the continuous casting blank is as follows: the thickness is 220mm, the width is 1580mm, and the length is 2700 mm; the chemical components and the contents of the obtained continuous casting billet are as follows: c: 0.23%, Si: 0.55%, Mn: 1.42%, P: 0.01%, S: 0.004%, Mo: 0.4%, Cr: 0.88%, Al: 0.024%, B:0.0024%, Ti: 0.017% and the balance of Fe and inevitable impurities.
(4) A slab heating procedure, wherein the heating furnace adopts a three-section type heating system: the first heating stage is 1100 ℃, the second heating stage is 1220 ℃, the soaking stage is 1200 ℃, and the furnace time is 4.5 h.
(5) Rolling, namely rolling by adopting a TMCP (thermal mechanical control processing) process, wherein the initial rolling temperature of a billet in one stage is 1150 ℃, the thickness to be cooled is 90mm, the initial rolling temperature of the billet in the second stage is 930 ℃, and the final rolling temperature is 820 ℃; the thickness dimension precision of the steel plate is realized by strictly controlling the service quantity of the rolling rolls, the rolling in the middle service period of the rolls is ensured, and the control range of the precision of the matched rolls is 0.2 mm; three secondary high-pressure water descaling and cooling control are adopted and respectively distributed to the second pass after the steel is rotated in the first stage, the first pass is rolled in the second stage, and the last but one third pass is rolled in the last stage, so that the large-thickness iron scale on the surface of the steel plate is effectively eliminated;
(6) a cooling process, in which water cooling is carried out on line, and the ratio of the water feeding amount to the water discharging amount is controlled to be 1: 1.3; the roller speed is 0.8m/s, the start cooling temperature is 800 ℃, the cooling speed is 10 ℃/s, and the final cooling temperature is 400 ℃;
(7) a heat treatment process, wherein a continuous roller hearth type heat treatment furnace is adopted for online tempering, and the tempering temperature is as follows: tempering at 500 deg.C for 54 min.
Example 2
As shown in fig. 2, the quenched and tempered wear-resistant steel plate NM400 with the thickness of 18mm comprises the following chemical components in percentage by mass: c: 0.23%, Si: 0.54%, Mn: 1.43%, P: 0.012%, S: 0.003%, Mo: 0.41%, Cr: 0.86%, Al: 0.025%, B:0.0021%, Ti: 0.016%, and the balance of Fe and inevitable impurities. As shown in FIG. 2, the metallographic structure of the steel sheet was tempered martensite, and the steel sheet had a uniform grain distribution and no mixed crystals or segregation.
The production method of the quenched and tempered wear-resistant steel plate NM400 with the thickness of 18mm comprises the following steps:
(1) the converter smelting process is characterized in that high-quality molten iron subjected to KR desulphurization treatment is added into molten iron fed into the converter, medium-carbon ferromanganese is added into the converter smelting process, the control end point P is less than or equal to 0.015 percent, Als (acid soluble aluminum) is 0.03 percent, double-slag-stopping tapping is carried out by adopting a slag stopping cone and a slag stopping plug, and slag thickness is as follows: 50mm, adding ferromolybdenum, ferrochromium, steel grit aluminum and lime for deoxidation and alloying during tapping, wherein the tapping temperature is as follows: 1630 deg.C.
(2) An LF furnace refining process, wherein large-slag-quantity slagging refining is carried out by adopting 1.0kg/t steel of a steel slag modifying agent, 1.8kg/t steel of refining slag and lime, slag is picked up and observed in the refining process, the addition of the lime is adjusted according to slag conditions, the white slag is kept for 18min, and the alkalinity is controlled at 5; and (3) feeding titanium wires of about 50m, boron wires of about 30m and calcium wires of about 70m in sequence at the later stage of refining, introducing argon for soft blowing and stirring to adjust titanium and calcium components in molten steel, carrying out boron microalloying, and controlling the tapping temperature at 1580 ℃.
The steel slag modified preparation mainly comprises the following components: al (Al)2O3：15%-25%，Al ：40%-45%，MgO：＜5%，SiO2：＜5%；
The refining slag comprises the following main components: al (Al)2O3：1%-2%，CaO：45%-55%，SiO2：18%-22%，MgO：20-25%，Fe2O3：0.5%-1.0%；
The steel slag modifier, the refining slag and the lime are added to adjust the alkalinity of molten steel in a refining furnace so as to realize the aims of desulfurization, dephosphorization and deoxidation.
(3) A slab continuous casting process, wherein the continuous casting adopts special casting powder (SiO)2：30%-35%，CaO：30%-35%，MgO：2%-5%，Al2O3：4%-8%，Na2O: 8% -14%) and protecting the casting in the whole process, wherein a water cooling system adopts a weak water cooling mechanism, the continuous casting blank enters a slow cooling pit for slow cooling for 48h after being cut, the drawing speed is 1.0m/min, and the specification of the continuous casting blank is as follows: the thickness is 220mm, the width is 1240mm, and the length is 2000 mm; the chemical components and the contents of the obtained continuous casting billet are as follows: c: 0.23%, Si: 0.54%, Mn: 1.43%, P: 0.012%, S: 0.003%, Mo: 0.41%, Cr: 0.86%, Al: 0.025%, B:0.0021%, Ti: 0.016%, and the balance of Fe and inevitable impurities.
(4) A slab heating procedure, wherein the heating furnace adopts a three-section type heating system: the first heating stage is 1000 ℃, the second heating stage is 1200 ℃, the soaking stage is 1180 ℃, and the furnace time is 5 hours.
(5) Rolling, namely rolling by adopting a TMCP (thermal mechanical control processing) process, wherein the initial rolling temperature of a billet in the first stage is 1120 ℃, the thickness to be cooled is 54mm, the initial rolling temperature of the second stage is 900 ℃, and the final rolling temperature is 820 ℃; the thickness dimension precision of the steel plate is realized by strictly controlling the service quantity of the rolling rolls, the rolling in the middle service period of the rolls is ensured, and the control range of the precision of the matched rolls is 0.2 mm; three secondary high-pressure water descaling and cooling control are adopted and respectively distributed to the second pass after the steel is rotated in the first stage, the first pass is rolled in the second stage, and the last but one third pass is rolled in the last stage, so that the large-thickness iron scale on the surface of the steel plate is effectively eliminated;
(6) a cooling process, in which water cooling is carried out on line, and the ratio of the water feeding amount to the water discharging amount is controlled to be 1: 1.3; the roller speed is 1m/s, the start cooling temperature is 780 ℃, the cooling speed is 15 ℃/s, and the final cooling temperature is 350 ℃;
(7) a heat treatment process, wherein a continuous roller hearth type heat treatment furnace is adopted for online tempering, and the tempering temperature is as follows: tempering at 450 deg.c for 32.4 min.
Table 1 chemical components obtained in examples 1 to 2 after sampling and testing;
table 2 mechanical property parameters obtained after sampling and testing in examples 1-2;
as can be seen from the data in the table 2, the NM400 quenched and tempered wear-resistant steel plate produced by the invention has excellent comprehensive mechanical properties, and has the advantages of tensile strength of more than or equal to 1200MPa, elongation of more than or equal to 13 and Hardness (HV) of more than or equal to 400. The steel plate produced by the method has stable performance and can realize industrial application.
Claims (5)
1. The method for producing the quenched and tempered wear-resistant steel plate NM400 with the thickness of less than 30mm by using online waste heat is characterized by comprising the following steps of: smelting in a converter, refining in an LF furnace, continuously casting a plate blank, heating the plate blank, rolling, cooling, thermally treating, sampling, detecting, marking and warehousing;
in the converter smelting process, high-quality molten iron subjected to KR method desulfurization treatment is added into molten iron fed into a converter, medium-carbon ferromanganese is added in the converter smelting process, the control end point P is less than or equal to 0.015 percent, Als is 0.03-0.05 percent, double-slag-blocking tapping is performed by adopting a slag-blocking cone and a slag-blocking plug, the slag thickness is less than or equal to 50mm, ferromolybdenum, ferrochromium, steel sand aluminum and lime are added during tapping for deoxidation and alloying, and the tapping temperature is as follows: 1630 ℃ and 1680 ℃;
in the LF furnace refining process, a large amount of slag is refined by using a steel slag modifier, refining slag and lime, slag is picked and observed in the refining process, the addition amount of the lime is adjusted according to slag conditions, the white slag is kept for more than or equal to 18min, and the alkalinity is controlled to be 5-7; feeding a titanium wire, a boron wire and a calcium wire in sequence at the later stage of refining, introducing argon for soft blowing and stirring, and controlling the tapping temperature to 1575-1585 ℃;
the slab continuous casting process is characterized in that the whole process is protected for casting, a water cooling system adopts a weak water cooling mechanism, the cut continuous casting slab enters a slow cooling pit for slow cooling for 48 hours at a drawing speed of 0.8-1.0m/min, and the specification of the continuous casting blank is as follows: the thickness is 220mm, the width is 1240-1580 mm, and the length is 2000-2700 mm; the chemical components and the contents of the continuous casting billet are as follows: c: 0.22 to 0.26%, Si: 0.4-0.6%, Mn: 1.3-1.55%, P is less than or equal to 0.020%, S is less than or equal to 0.007%, Mo: 0.3-0.45%, Cr: 0.8-0.95%, Als: 0.01-0.035%, B0.001-0.005%, Ti less than or equal to 0.04%, and the balance of Fe and inevitable impurities;
in the slab heating process, the heating furnace adopts a three-section type heating system: heating the first section at 1100 ℃ for 1000-;
the rolling procedure adopts a TMCP (thermal mechanical control processing) process for rolling, wherein the initial rolling temperature of the billet in the first stage is 1120-1150 ℃, the thickness to be cooled is 2-3 times of the thickness of the finished product, the initial rolling temperature in the second stage is 860-930 ℃, and the final rolling temperature is 800-820 ℃; the thickness dimension precision of the steel plate is realized by strictly controlling the service quantity of the rolling rolls, the rolling in the middle service period of the rolls is ensured, and the control range of the precision of the matched rolls is 0-0.4 mm; three secondary high-pressure water descaling and cooling control are adopted and respectively distributed to the second pass after the steel is rotated in the first stage, the first pass is rolled in the second stage, and the last but one third pass is rolled in the last stage, so that the large-thickness iron scale on the surface of the steel plate is effectively eliminated;
in the cooling procedure, water cooling is adopted, and the ratio of the water feeding amount to the water discharging amount is controlled to be about 1: 1.3; the roller speed is 0.8-1.2m/s, the start cooling temperature is 780-800 ℃, the cooling speed is 10-15 ℃/s, and the final cooling temperature is 350-400 ℃;
the heat treatment process adopts a continuous roller hearth type heat treatment furnace for on-line tempering, and the tempering temperature is as follows: 450 ℃ and 500 ℃, and the tempering time is 1.8Tmin, wherein T is the thickness of the steel plate.
2. The method for producing the quenched and tempered wear-resistant steel plate NM400 with the thickness of less than 30mm by using the on-line waste heat according to claim 1The steel slag modifier is characterized in that in the LF refining process, the steel slag modifier mainly comprises the following components: al (Al)2O3：15%-25%，Al ：40%-45%，MgO：＜5%，SiO2: less than 5 percent, the steel slag modified preparation comprises the following components in percentage by weight: 1.0-1.3 kg per ton steel.
3. The method for producing the NM400 quenched and tempered wear-resistant steel plate with the thickness of 30mm or less by using the on-line waste heat as claimed in claim 1, wherein in the LF refining process, the refining slag mainly comprises the following components: al (Al)2O3：1%-2%，CaO：45%-55%，SiO2：18%-22%，MgO：20-25%，Fe2O3: 0.5 to 1.0 percent, and the addition amount of the refining slag is as follows: 1.8-2.2 kg per ton steel.
4. An NM400 hardened and tempered wear-resistant steel plate with a thickness of 30mm or less produced by the method of any one of claims 1 to 3, wherein the NM400 hardened and tempered wear-resistant steel plate has a chemical composition of C: 0.22 to 0.26%, Si: 0.4-0.6%, Mn: 1.3-1.55%, P is less than or equal to 0.020%, S is less than or equal to 0.007%, Mo: 0.3-0.45%, Cr: 0.8-0.95%, Al: 0.01-0.035%, 0.001-0.005% of B, less than or equal to 0.04% of Ti, and the balance of Fe and inevitable impurities.
5. The NM400 of the quenched and tempered wear-resistant steel plate with the thickness of 30mm below according to claim 4, wherein the mechanical property parameters of the quenched and tempered wear-resistant steel plate NM400 are as follows: the tensile strength is more than or equal to 1200MPa, the elongation is more than or equal to 13, the Hardness (HV) is more than or equal to 400, and the metallographic structure is tempered martensite.
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| CN115896621A (en) * | 2022-11-18 | 2023-04-04 | 江阴兴澄特种钢铁有限公司 | Thin-specification high-quality plate-shaped NM400 steel plate produced by adopting online quenching process and manufacturing method thereof |
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| CN102943213A (en) * | 2012-11-28 | 2013-02-27 | 钢铁研究总院 | Abrasion-resistant steel for low-alloy ultra-high strength engineering machine and preparation method thereof |
| CN103205627A (en) * | 2013-03-28 | 2013-07-17 | 宝山钢铁股份有限公司 | Low-alloy high-performance wear-resistant steel plate and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102943213A (en) * | 2012-11-28 | 2013-02-27 | 钢铁研究总院 | Abrasion-resistant steel for low-alloy ultra-high strength engineering machine and preparation method thereof |
| CN103205627A (en) * | 2013-03-28 | 2013-07-17 | 宝山钢铁股份有限公司 | Low-alloy high-performance wear-resistant steel plate and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115896621A (en) * | 2022-11-18 | 2023-04-04 | 江阴兴澄特种钢铁有限公司 | Thin-specification high-quality plate-shaped NM400 steel plate produced by adopting online quenching process and manufacturing method thereof |
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