A kind of NM450F high toughness mine car carriage wear-resistant steel plate for polar low temperature-60 ℃ and its production method

Abstract

The application discloses a kind of polar low temperature-60 ℃ NM450F high toughness mine car carriage wear-resistant steel plate, it is characterized by: the chemical composition of the steel plate is as follows by weight percentage C:0.19-0.21%, Si:0.35-0.45%, Mn:1.10-1.20%, P:≤0.020%, S:≤0.005%, Cr:0.20-0.35%, Mo:0.10-0.20%, B:0.0008-0.0015%, Ce:0.0012-0.0020%, the balance is Fe and inevitable impurities.It also discloses its production method.The application obtains high toughness mine car carriage wear-resistant steel plate by low temperature component design and corresponding rolling, heat treatment process cooperation, has high low temperature toughness, high strength, high hardness, guarantees the safe working performance of low temperature mine car, and prolongs the service life of mine car bottom plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of low-temperature wear-resistant steel, in particular to a high-toughness wear-resistant steel plate for mine carriages used in polar low-temperature environments (-60℃) with a thickness of 20-30 mm and a production method thereof. BACKGROUND

[0002] Mining and energy development and construction in polar cold regions cannot be carried out without low-temperature mining vehicles and transport vehicles that can adapt to the harsh service environment of polar cold regions. Although traditional wear-resistant steel plates have high strength, high hardness and good wear resistance, their low-temperature toughness is poor and they are prone to failure in low-temperature environments, causing losses to users. Therefore, wear-resistant steel with high strength and high low-temperature toughness is of great significance to the development of polar cold regions and has a high market development and promotion value. With the surface hardness guaranteed, the high low-temperature toughness can ensure that the mine carriages will not easily crack and be damaged due to extremely low temperatures during the mining and loading process, and the wear resistance of the wear-resistant steel carriage at extremely low temperatures is improved, ensuring the safe working performance of the low-temperature mining vehicle and prolonging the service life of the mine vehicle bottom plate.

[0003] The application with the application publication number CN 110184532 A discloses a wear-resistant steel plate with excellent -60℃ ultra-low temperature impact toughness and a production method thereof. The chemical components contain, by weight wt%, C: 0.12-0.20%, Si: 0.10-0.40%, Mn: 0.8-1.30%, Nb: 0.010-0.040%, V: 0.020-0.050%, Ti: ≤0.010%, Al: 0.04-0.08%, Ni: ≤0.1%, Cu: ≤0.1%, Cr: 0.20-0.60%, Mo: 0.30-0.80%, B: 0.001-0.005%, Ca: ≤0.0015%, P: ≤0.010%, S: ≤0.0015%, O: ≤0.0015%, N: ≤0.0035%, H: ≤0.0002%, and satisfy 0.16≤(Mn+Mo) / 10+Cr / 20≤0.26, S+P+O+N+H≤0.015%, the balance being Fe and unavoidable impurity elements. The process steps are: smelting -> secondary refining -> vacuum degassing -> continuous casting -> slow cooling treatment of the cast blank -> heating -> rolling -> quenching -> stress relief correction. The present application has economical components, simple process, and the steel plate has fine lath martensite structure and excellent comprehensive mechanical properties, meeting the use requirements of the low-temperature wear-resistant steel plate in the domestic and foreign large-scale mechanical industry. The difference between the present application and the above-mentioned application is that the component design is obviously different, the component design of the present application does not contain Ni, Cu, Nb, V and other noble metals, the component design of the present application has lower alloy cost and has obvious cost advantage. Moreover, the steel plate of the present application has more excellent performance.

[0004] The invention with publication number CN 109811260 A discloses a wear-resistant steel plate for extremely cold regions and a manufacturing method. The chemical composition in mass percentage is: C: 0.18%-0.23%, Si: 0.20%-0.50%, Mn: 1.0%-1.50%, P≤0.010%, S≤0.002%, Cr: 0.10%-0.30%, Mo: 0.10%-0.30%, Ni: 0.30%-0.8%, Ti: 0.008%-0.030%, Nb: 0.012%-0.040%, B: 0.0008%-0.0025%, and the rest is Fe and inevitable impurities. The invention adopts a medium-high carbon and alloying composition design, and a method of auxiliary rolling and offline heat treatment, so that the obtained steel plate has a wear-resistant steel with a Brinell hardness of 450HBW level, and a low temperature impact toughness of ≥34J at-60℃. The difference between the invention and the above-mentioned invention is first in the composition design, which does not contain Ni, Nb and other noble metals. The composition design of the invention has lower alloy cost and obvious cost advantage. The performance of the invention is obviously different from the above-mentioned invention. The steel plate structure of the invention is obviously different from the above-mentioned invention. The thickness range of the invention is also different from the above-mentioned invention.

[0005] The invention with publication number CN 116103478 A discloses a preparation method of low-stress high-toughness thin-gauge wear-resistant steel. The method produces low-stress high-toughness thin-gauge wear-resistant steel plate through specific component design combined with offline heat treatment. The specific component design uses laterite nickel ore instead of nickel alloy to produce high-toughness wear-resistant steel, and controls the nickel content to be 0.50-2.00wt.%. After hot rolling, the steel plate is coiled, flattened, and then offline heat treated. The offline heat treatment adopts roll pressing type constraint quenching and low temperature tempering through hot air flue gas circulation heating. The method simplifies the production process, reduces the production cost, and improves the strength and toughness of the wear-resistant steel and the formability. The low-stress high-toughness thin-gauge wear-resistant steel is produced, the steel plate hardness is 360-500HB, the tensile strength is 1100-1650MPa, the elongation is 11%-15%, the steel plate residual stress is below 100MPa, and the impact toughness at-60℃ can reach above 50J / cm 2. The difference between the invention and the above-mentioned invention is first in the composition design, which is obviously different. The C and Mn contents are obviously different, and the invention does not contain noble metal Ni. The composition design of the invention has much lower alloy cost than the above-mentioned invention, and has obvious cost advantage. The thickness range of the steel plate produced by the invention is also different from the above-mentioned invention. SUMMARY

[0006] The purpose of the present application is to provide a polar low temperature -60℃ NM450F high toughness mine car carriage wear-resistant steel plate and its production method, through low temperature component design and corresponding rolling, heat treatment process, the polar low temperature (-60℃) high toughness mine car carriage wear-resistant steel plate with thickness of 20-30mm is obtained, which has high low temperature toughness, high strength and high hardness, ensures the safe working performance of low temperature mine car, and prolongs the service life of mine car bottom plate.

[0007] To solve the above technical problems, the present application adopts the following technical scheme:

[0008] The polar low temperature -60℃ NM450F high toughness mine car carriage wear-resistant steel plate of the present application has the following chemical composition by weight percentage: C: 0.19-0.21%, Si: 0.35-0.45%, Mn: 1.10-1.20%, P: ≤0.020%, S: ≤0.005%, Cr: 0.20-0.35%, Mo: 0.10-0.20%, B: 0.0008-0.0015%, Ce: 0.0012-0.0020%, and the balance is Fe and inevitable impurities.

[0009] Further, the chemical composition of the steel plate has the following weight percentage: C: 0.207%, Si: 0.37%, Mn: 1.17%, P: 0.013%, S: 0.003%, Cr: 0.33%, Mo: 0.18%, B: 0.0014%, Ce: 0.0019%, and the balance is Fe and inevitable impurities.

[0010] Further, the chemical composition of the steel plate has the following weight percentage: C: 0.198%, Si: 0.42%, Mn: 1.15%, P: 0.012%, S: 0.002%, Cr: 0.28%, Mo: 0.16%, B: 0.0010%, Ce: 0.0016%, and the balance is Fe and inevitable impurities.

[0011] Further, the chemical composition of the steel plate has the following weight percentage: C: 0.192%, Si: 0.42%, Mn: 1.11%, P: 0.015%, S: 0.003%, Cr: 0.22%, Mo: 0.13%, B: 0.0008%, Ce: 0.0012%, and the balance is Fe and inevitable impurities.

[0012] A production method of a polar low temperature -60℃ NM450F high toughness mine car carriage wear-resistant steel plate, comprising the following steps:

[0013] 1) Smelting

[0014] The molten iron is pretreated by desulfurization, low-sulfur scrap steel is added in the converter smelting process, the tapping temperature of the converter is required to be ≥1620℃, the molten steel composition is required to reach the requirements in the LF refining process, and the white slag formation time is required to be ensured, the vacuum treatment time of the RH furnace is ≥20min, and the molten steel after vacuum treatment is required to reach: H≤2.0ppm, N≤70ppm;

[0015] 2), continuous casting

[0016] The continuous casting process adopts protective casting, and the casting process requires that the casting speed be kept stable, the casting speed be selected in the range of 0.80-1.2m / min, and then the casting speed be kept constant as much as possible. After the continuous casting billet is cut off and discharged, it is required to be stacked and slowly cooled, and the stacking position should be avoided to be at the air port position of the warehouse area;

[0017] 3), heating and rolling

[0018] The continuous casting billet heating furnace discharge temperature range is 1150±20℃, the steel plate rolling adopts two-stage rolling, the finish rolling temperature is selected to be 800-830℃, and the rolling is rapidly cooled to 670-720℃;

[0019] 4), heat treatment process

[0020] The steel plate adopts a quenching and tempering heat treatment process, wherein:

[0021] Quenching process: quenching holding temperature 880±10℃, quenching holding time 10-20min;

[0022] Tempering process: tempering holding temperature 180±10℃, tempering holding time 30-60min, and then the tempered billet is discharged and slowly cooled.

[0023] Further, the continuous casting billet rolling heating furnace discharge temperature is 1165℃, the billet rolling adopts two-stage rolling, the finish rolling temperature is 837℃, and the rolling is rapidly cooled to 716℃; the quenching process is: quenching holding temperature 889℃, holding for 20min, and then quenching; the tempering process is: tempering holding temperature 172℃, holding for 55min, and then the billet is discharged and slowly cooled, so that the steel plate is obtained.

[0024] Further, the continuous casting billet rolling heating furnace discharge temperature is 1151℃, the billet rolling adopts two-stage rolling, the finish rolling temperature is 827℃, and the rolling is rapidly cooled to 695℃; the quenching process is: quenching holding temperature 878℃, holding for 16min, and then quenching; the tempering process is: tempering holding temperature 179℃, holding for 45min, and then the billet is discharged and slowly cooled, so that the steel plate is obtained.

[0025] Further, the heating furnace out-furnace temperature of the continuous casting slab rolling is 1135℃, the slab rolling adopts two-stage rolling, the finish rolling temperature is 815℃, and the slab is rapidly cooled to 673℃ after rolling; the quenching process is that the quenching holding temperature is 872℃, and the quenching is carried out after holding for 12min; the tempering process is that the tempering holding temperature is 188℃, and the furnace is discharged after holding for 35min and slow cooling, so that the steel plate is obtained.

[0026] Compared with the prior art, the present application has the beneficial technical effects:

[0027] The present application develops a NM450 grade wear-resistant steel plate with high impact toughness at-60℃, which can work normally at-60℃ extremely low ambient temperature. The wear-resistant steel has low cost and excellent cost performance. BRIEF DESCRIPTION OF DRAWINGS

[0028] The present application will be further described below in combination with the description of the accompanying drawings.

[0029] Figure 1 The metallographic structure of the steel plate of Example 1;

[0030] Figure 2 The metallographic structure of the steel plate of Example 2;

[0031] Figure 3 The metallographic structure of the steel plate of Example 3. DETAILED DESCRIPTION

[0032] As Figure 1 shown in the figure, a NM450F high-toughness wear-resistant steel plate for polar low temperature-60℃ mine car carriage

[0033] The present application aims to provide a NM450F high-toughness wear-resistant steel plate for polar low temperature(-60℃) mine car carriage and a production method thereof. Through reasonable component design and simple production process, the NM450F wear-resistant steel plate for mine car bottom plate with high low-temperature impact toughness, high hardness and high strength can be obtained.

[0034] The production method of the wear-resistant steel comprises the following steps:

[0035] 1. Smelting

[0036] Desulfurized pretreated molten iron is adopted for smelting. Low-sulfur scrap steel is added in the converter smelting process, and the tapping temperature of the converter is required to be ≥1620℃. The LF refining is required to ensure that the molten steel composition meets the requirements, and the white slag formation time is required to be ensured. The vacuum treatment time of the RH furnace is ≥20min, and the molten steel after vacuum treatment is required to meet: H≤2.0ppm, N≤70ppm.

[0037] 2. Continuous casting

[0038] The continuous casting process should adopt protective casting, and the casting process requires that the casting speed should be kept stable, and the casting speed should be selected in the range of 0.80-1.2 m / min, and then the casting speed should be kept constant. After the continuous casting billet is cut off and discharged, it should be stacked and slowly cooled, and the stacking position should be avoided to be located at the air outlet position of the warehouse area.

[0039] 3. Heating and rolling

[0040] The discharge temperature of the continuous casting billet heating furnace is in the range of 1150±20℃. The rolling of the steel plate adopts two-stage rolling, and the finish rolling temperature is selected to be 800-830℃, and the rolling is rapidly cooled to 670-720℃.

[0041] 4. Heat treatment process

[0042] The steel plate adopts the heat treatment process of quenching and tempering.

[0043] Quenching process: the quenching holding temperature is 880±10℃, and the quenching holding time is 10-20 min.

[0044] Tempering process: the tempering holding temperature is 180±10℃, and the tempering holding time is 30-60 min, and then the steel plate is discharged and stacked and slowly cooled.

[0045] Example 1

[0046] The chemical composition of the steel plate of Example 1 is shown in Table 1. The discharge temperature of the heating furnace for the continuous casting slab rolling is 1165℃. The rolling of the slab adopts two-stage rolling, and the finish rolling temperature is 837℃, and the rolling is rapidly cooled to 716℃. The quenching process: the quenching holding temperature is 889℃, and the holding time is 20 min. The tempering process: the tempering holding temperature is 172℃, and the holding time is 55 min, and then the steel plate is discharged and slowly cooled. Thus, the steel plate is obtained. The mechanical properties of the steel plate are shown in Table 2, and the metallographic structure of the steel plate is shown in Figure 1 .

[0047] Example 2

[0048] The chemical composition of the steel plate of Example 3 is shown in Table 1. The discharge temperature of the heating furnace for the continuous casting slab rolling is 1151℃. The rolling of the slab adopts two-stage rolling, and the finish rolling temperature is 827℃, and the rolling is rapidly cooled to 695℃. The quenching process: the quenching holding temperature is 878℃, and the holding time is 16 min. The tempering process: the tempering holding temperature is 179℃, and the holding time is 45 min, and then the steel plate is discharged and slowly cooled. Thus, the steel plate is obtained. The mechanical properties of the steel plate are shown in Table 2, and the metallographic structure of the steel plate is shown in Figure 1 .

[0049] Example 3

[0050] The chemical composition of the steel sheet of Example 3 is shown in Table 1. The heating furnace exit temperature of the continuous casting slab was 1135°C. The slab was rolled by two-stage rolling, and the finish rolling temperature was 815°C, and the rapid cooling after rolling was to 673°C. The quenching process was: quenching at 872°C for 12 minutes. The tempering process was: tempering at 188°C for 35 minutes, and then slow cooling after furnace exit. Thus the steel sheet was obtained. The mechanical properties of the steel sheet are shown in Table 2, and the microstructure of the steel sheet is shown in Figure 1

[0051] Table 1: Chemical composition of the steel sheet (wt%)

[0052]

[0053] Table 2: Properties of the steel sheet

[0054]

[0055] The above-described examples are merely preferred modes of the present application, and are not intended to limit the scope of the present application. Various modifications and improvements to the technical solutions of the present application made by those of ordinary skill in the art without departing from the design spirit of the present application shall fall within the scope of protection of the present application as defined by the claims.​

Claims

1. A NM450F high-toughness wear-resistant steel plate for a mine car body for polar low temperature -60℃, characterized in that: The chemical composition of the steel plate is C: 0.19-0.21%, Si: 0.35-0.45%, Mn: 1.10-1.20%, P: ≤0.020%, S: ≤0.005%, Cr: 0.20~0.35%, Mo: 0.10-0.20%, B: 0.0008-0.0015%, Ce: 0.0012~0.0020%, and the balance is Fe and inevitable impurities; The production method comprises the following steps: 1) smelting The molten iron is subjected to desulfurization pretreatment and smelting, low-sulfur scrap steel is added in the converter smelting process, the tapping temperature of the converter is required to be ≥1620℃, the molten steel composition is required to reach the requirements in the LF refining, and the white slag formation time is required to be guaranteed, the vacuum treatment time of the RH furnace is ≥20min, and the molten steel after vacuum treatment is required to reach: H≤2.0ppm, N≤70ppm; 2) continuous casting The continuous casting process adopts protective casting, the casting process requires that the casting speed be kept stable, the casting speed in the casting process is selected in the range of 0.80~1.2m / min, and then the casting speed is kept constant as much as possible, and the continuous casting blank is stacked and slowly cooled after cutting and offline, and the stacking position should avoid the position of the air port in the warehouse area; 3) heating and rolling The continuous casting blank heating furnace has an outlet temperature in the range of 1150±20℃, the steel plate is rolled by two-stage rolling, the finish rolling temperature is selected to be 800~830℃, and the steel plate is rapidly cooled to 670-720℃ after rolling; 4) heat treatment process The steel plate adopts a quenching and tempering heat treatment process, wherein: Quenching process: quenching holding temperature 880±10℃, quenching holding time 10~20min; Tempering process: tempering holding temperature 180±10℃, tempering holding time 30~60min, and then the steel plate is stacked and slowly cooled after the tempering furnace is discharged.

2. The NM450F high-toughness abrasion-resistant steel plate for a mine car body for polar low temperature -60℃ according to claim 1, characterized in that: The chemical composition of the steel plate is C: 0.207%, Si: 0.37%, Mn: 1.17%, P: 0.013%, S: 0.003%, Cr: 0.33%, Mo: 0.18%, B: 0.0014%, Ce: 0.0019%, and the balance is Fe and inevitable impurities.

3. The NM450F high-toughness abrasion-resistant steel plate for a mine car body for polar low temperature -60℃ according to claim 1, characterized in that: The chemical composition of the steel plate is C: 0.198%, Si: 0.42%, Mn: 1.15%, P: 0.012%, S: 0.002%, Cr: 0.28%, Mo: 0.16%, B: 0.0010%, Ce: 0.0016%, and the balance is Fe and inevitable impurities.

4. The NM450F high-toughness abrasion-resistant steel plate for a mine car body for polar low temperature -60℃ according to claim 1, characterized in that: The chemical composition of the steel plate is C: 0.192%, Si: 0.42%, Mn: 1.11%, P: 0.015%, S: 0.003%, Cr: 0.22%, Mo: 0.13%, B: 0.0008%, Ce: 0.0012%, and the balance is Fe and inevitable impurities.

5. The NM450F high-toughness abrasion-resistant steel plate for a mine car body for polar low temperature -60℃ according to claim 1, characterized in that: The heating furnace out-furnace temperature of the continuous casting slab rolling is 1151℃, the slab rolling adopts two-stage rolling, the finish rolling temperature is 827℃, and the rolling is rapidly cooled to 695℃; the quenching process is that the quenching holding temperature is 878℃, and the slab is quenched after holding for 16 minutes; the tempering process is that the tempering holding temperature is 179℃, and the slab is out-furnace and slowly cooled after holding for 45 minutes, so that the steel plate is obtained.

6. The NM450F high-toughness abrasion-resistant steel plate for a mine car body for polar low temperature -60℃ according to claim 1, characterized in that: The heating furnace out-furnace temperature of the continuous casting slab rolling is 1135℃, the slab rolling adopts two-stage rolling, the finish rolling temperature is 815℃, and the rolling is rapidly cooled to 673℃; the quenching process is that the quenching holding temperature is 872℃, and the slab is quenched after holding for 12 minutes; the tempering process is that the tempering holding temperature is 188℃, and the slab is out-furnace and slowly cooled after holding for 35 minutes, so that the steel plate is obtained.

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