Preparation method of NM300TP wear-resistant steel and NM300TP wear-resistant steel

Abstract

The invention discloses a preparation method of NM300TP wear-resistant steel and the NM300TP wear-resistant steel. The method comprises the steps that a rolled NM300TP steel coil sequentially passes through a first pickling bath to a fifth pickling bath at the pickling speed of 20 m / min to 100 m / min to be subjected to pickling, a pickled steel strip is prepared, the NM300TP steel coil comprises, by mass, 0.10%-0.16% of C, 1.0%-1.5% of Si, 1.5%-2.0% of Mn, smaller than or equal to 0.020% of P, smaller than or equal to 0.005% of S, 0.4%-0.6% of Als, smaller than or equal to 0.030% of Ti and the balance Fe and other inevitable impurities, the temperature of an acid solution for pickling is 60 DEG C to 100 DEG C, and the pickling time is 2-3 h; the acid concentration of pickling is 30 g / L-300 g / L, and the surface of the NM300TP steel coil comprises oxidized scale; and the acid-washed steel strip is rinsed, squeezed and dried, the NM300TP wear-resistant steel is prepared, and the pressure of a squeezing roller ranges from 0.1 MPa to 0.8 MPa. According to the method, the red oxide gray on the surface of the NM300TP wear-resistant steel is removed, the surface quality of the NM300TP wear-resistant steel is improved, and meanwhile, the production efficiency of the NM300TP wear-resistant steel is considered.

Description

Technical Field

[0001] The present application belongs to the technical field of wear-resistant steel preparation, and specifically relates to a preparation method of NM300TP wear-resistant steel and NM300TP wear-resistant steel. Background Art

[0002] NM300TP is a wear-resistant steel with a dual-phase structure of ferrite and martensite, which can be used to make the tank body of a concrete mixer truck. It has good processing performance and rolling performance, and can meet the design and manufacturing of concrete mixing tank bodies.

[0003] The traditional concrete mixer truck tank body is made of 500MPa high-strength steel with a thickness of 6mm, and the tank body weighs 2.7 tons; when the tank body material is upgraded to NM300TP wear-resistant steel with a tensile strength of 1100MPa, after equivalent substitution, the thickness only needs to be 4mm, which can reduce the weight by about 33%, and the upgraded tank body weighs less than 2 tons. With the requirements of GB / T26408-2020 "Concrete Mixer Truck", concrete mixer trucks are upgraded and improved in the direction of lightweight, intelligent, safe, durable, comfortable and environmentally friendly, and the requirements for vehicle load, lightweight and fuel consumption are constantly increasing.

[0004] Due to its composition, the surface of NM300TP wear-resistant steel turns red and is prone to oxidation and dust accumulation, which interferes with the intelligent identification of mixer truck manufacturers and causes production interruptions on the automated production line. The fallen red oxide ash has an adverse impact on the environment and does not meet the requirements of environmental protection and green development. Therefore, it is urgent to solve the surface quality problem of NM300TP. Summary of the invention

[0005] In view of this, the present application provides a preparation method of NM300TP wear-resistant steel and NM300TP wear-resistant steel, aiming to provide a method for removing red oxide ash on the surface of NM300TP wear-resistant steel, improve the surface quality of NM300TP wear-resistant steel, and take into account the production efficiency of NM300TP wear-resistant steel.

[0006] In a first aspect, an embodiment of the present application provides a method for preparing NM300TP wear-resistant steel, comprising:

[0007] The rolled NM300TP steel coil is sequentially passed through a 1# pickling tank to a 5# pickling tank at a speed of 20 m / min-100 m / min for pickling to obtain a pickled steel strip, wherein the NM300TP steel coil includes the following chemical elements by mass percentage: C: 0.10%-0.16%, Si: 1.0%-1.5%, Mn: 1.5%-2.0%, P≤0.020%, S≤0.005%, Als: 0.4%-0.6%, Ti≤0.030%, and the balance is Fe and other inevitable impurities, the pickling acid solution temperature is 60°C-100°C, the pickling acid concentration is 30g / L-300g / L, and the surface of the NM300TP steel coil includes iron oxide scale;

[0008] The pickled steel strip is rinsed, squeezed and dried to obtain NM300TP wear-resistant steel, wherein the squeezing roller pressure is 0.1MPa-0.8MPa.

[0009] According to an embodiment of one aspect of the present application, the acid concentrations in the 1# pickling tank and the 2# pickling tank are 30g / L-100g / L respectively; the acid concentration in the 3# pickling tank is 50g / L-180g / L; the acid concentration in the 4# pickling tank is 50g / L-180g / L; and the acid concentration in the 5# pickling tank is 100g / L-300g / L.

[0010] According to an embodiment of one aspect of the present application, the thickness of the NM300TP steel coil is 2mm-6mm.

[0011] According to an embodiment of one aspect of the present application, the conductivity of the rinsing solution in the rinsing tank is 200 μs / cm-800 μs / cm, and the water temperature of the rinsing solution is 30° C.-90° C.

[0012] According to an embodiment of one aspect of the present application, rinsing includes a 1# rinsing tank, and the pH value of the rinsing liquid in the 1# rinsing tank is 1.5 to 5.0.

[0013] According to an embodiment of one aspect of the present application, rinsing includes rinsing tank #1 to rinsing tank #5.

[0014] According to an embodiment of one aspect of the present application, the pickled steel strip is rinsed at a speed of 20 m / min-100 m / min.

[0015] According to an embodiment of one aspect of the present application, the surface of the NM300TP steel coil includes 10 μm-20 μm of iron oxide scale.

[0016] According to an embodiment of one aspect of the present application, the acid includes hydrochloric acid, and the rinsing water in the 5# rinsing tank meets the following conditions: conductivity is less than 2.5us / cm, pH is 6-8, chloride ions are 0.5-1.5mg / L, sodium ions are 1-10ug / L, and silica is 10-50ug / L.

[0017] In a second aspect, an embodiment of the present application provides a NM300TP wear-resistant steel, which is prepared by the preparation method of the NM300TP wear-resistant steel of the first aspect.

[0018] This application has at least the following beneficial effects:

[0019] The preparation method provided in the present application is that the NM300TP steel coil is pickled in sequence through a 1# pickling tank, a 2# pickling tank, a 3# pickling tank, a 4# pickling tank, and a 5# pickling tank at a pickling speed of 20m / min-100m / min. Since the surface of the NM300TP steel coil includes iron oxide scale, an acid solution with a temperature of 60°C-100°C and an acid concentration of 30g / L-300g / L is used for pickling, which can more thoroughly remove the surface of the NM300TP steel coil including the oxide scale on the basis of taking into account the acid speed; after rinsing, squeezing, and drying, the red iron oxide scale and oxide dust on the surface are washed away to obtain a NM300TP steel coil with a smooth surface and a silver-gray color. After the steel coil in this state is used by the user, no surface treatment is required. The silver-gray steel plate will not interfere with the image recognition system in the automatic control process, and will not generate red oxidized dust. On the basis of taking into account the production efficiency, the surface iron oxide scale of the steel coil is effectively removed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the implementation regulations of this application, the following is a brief introduction to the drawings required for use in the embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 The figure shows the appearance of the steel plate after pickling in Comparative Example 1 of the present application.

[0022] Figure 2 The figure shows the appearance of the wear-resistant steel after pickling of Example 1 of the present application. DETAILED DESCRIPTION

[0023] In order to make the application purpose, technical solution and beneficial technical effect of this application clearer, the application is further described in detail below in conjunction with the embodiments. It should be understood that the implementation regulations described in this specification are only for explaining this application, not for limiting this application.

[0024] For simplicity, the present application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range, and any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unclearly recorded range.

[0025] In the description of the present application, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number, and the “multiple” in “one or more” means two or more than two.

[0026] The above application content of the present application is not intended to describe each disclosed embodiment or each implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided through a series of embodiments, and these implementation regulations can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0027] In a first aspect, an embodiment of the present application provides a method for preparing NM300TP wear-resistant steel, the method comprising:

[0028] The rolled NM300TP steel coil is sequentially passed through a 1# pickling tank to a 5# pickling tank at a speed of 20 m / min-100 m / min for pickling to obtain a pickled steel strip, wherein the NM300TP steel coil includes the following chemical elements by mass percentage: C: 0.10%-0.16%, Si: 1.0%-1.5%, Mn: 1.5%-2.0%, P≤0.020%, S≤0.005%, Als: 0.4%-0.6%, Ti≤0.030%, and the balance is Fe and other inevitable impurities, the pickling acid solution temperature is 60°C-100°C, the pickling acid concentration is 30g / L-300g / L, and the surface of the NM300TP steel coil includes iron oxide scale;

[0029] The pickled steel strip is rinsed, squeezed and dried to obtain NM300TP wear-resistant steel, wherein the squeezing roller pressure is 0.1MPa-0.8MPa.

[0030] Other alloying elements in steel, such as titanium (Ti) and aluminum (Al), make the steel more wear-resistant. However, this type of steel also has a certain impact on the formation of oxides and the surface quality of the steel. The iron in this type of steel is oxidized to produce red oxides, etc.

[0031] According to the embodiment of the present application, there are red iron oxide scale and oxidized dust on the surface of the steel strip after rolling. The pickling passes through the 1# pickling tank to the 5# pickling tank, and an acid solution with a temperature of 60℃-100℃ and an acid concentration of 30g / L-300g / L is used for pickling. The surface of the NM300TP steel coil including the iron oxide scale can be more thoroughly removed while taking into account the acid speed; then the rinsed NM300TP steel coil is passed through a squeezing roller to squeeze out the water, and the squeezing roller pressure is 0.1MPa-0.8MPa to avoid residual moisture on the surface of the steel strip and to avoid oxidation and reddening of the surface of the steel strip again. Finally, the squeezed NM300TP steel coil is hot-air dried to obtain the finished NM300TP wear-resistant steel.

[0032] Iron oxide scale is a red iron oxide substance.

[0033] In some optional embodiments, the properties of the NM300TP steel coil meet the following requirements: yield strength of 550-750 MPa, tensile strength of 1000-1200 MPa, surface Brinell hardness of 270-330 HB, ferrite volume fraction of the steel plate of about 40-60%, and the rest being martensite structure.

[0034] In some optional embodiments, the method further comprises: obtaining molten iron from a blast furnace, and subjecting the molten iron from the blast furnace to converter smelting, RH refining, and continuous casting to obtain NM300TP ingots;

[0035] Secondly, the ingot is heated, rolled, cooled and coiled to obtain a rolled NM300TP steel coil.

[0036] In some optional embodiments, the width of the rolled NM300TP steel coil is 800 mm-2130 mm.

[0037] In some optional embodiments, in order to remove the red oxide on the surface of the steel strip, a suitable acid can be selected to pickle the steel strip, and the acid concentrations in the 1# pickling tank and the 2# pickling tank are 30g / L-100g / L respectively; the acid concentration in the 3# pickling tank is 50g / L-180g / L; the acid concentration in the 4# pickling tank is 50g / L-180g / L; and the acid concentration in the 5# pickling tank is 100g / L-300g / L.

[0038] The type of acid may be sulfuric acid, hydrochloric acid, etc.

[0039] In some optional embodiments, the thickness of the NM300TP steel coil is 2 mm to 6 mm. The thickness of the NM300TP steel coil can be any value among 2 mm, 3 mm, 4 mm, 5 mm, 6 mm or a range thereof.

[0040] In some optional embodiments, in order to remove the acid remaining on the surface of the steel strip, the degree of rinsing is controlled, the conductivity of the rinsing solution is 200 μs / cm-800 μs / cm, and the water temperature of the rinsing solution is 30° C.-90° C.

[0041] In some optional embodiments, rinsing includes a 1# rinsing tank, and the pH value of the rinsing liquid in the 1# rinsing tank is 1.5 to 5.0. Controlling the pH value of the rinsing liquid within the above range has the effect of preventing acid from leaking into the rinsing tank and causing the surface of the steel plate to rust and turn yellow.

[0042] In some optional embodiments, rinsing includes rinsing tank #1 to rinsing tank #5.

[0043] In some optional embodiments, in order to balance production efficiency and match the pickling speed and reduce the red oxide on the surface of the steel strip, the pickled steel strip is rinsed, squeezed and dried at a speed of 20m / min-100m / min to produce NM300TP wear-resistant steel.

[0044] In some optional embodiments, the surface of the NM300TP steel coil includes 10 μm-20 μm of iron oxide scale.

[0045] In some optional embodiments, the iron oxide scale includes, by mass percentage: Fe2O3≤15%, Fe3O4≥85%, and the remainder is steel coil components and unavoidable impurities.

[0046] In some optional embodiments, the acid includes hydrochloric acid, and the rinsing water in the 5# rinsing tank meets the following conditions: conductivity is less than 2.5us / cm, pH is 6-8, chloride ions are 0.5-1.5mg / L, sodium ions are 1-10ug / L, and silica is 10-50ug / L.

[0047] By detecting the salt content contained in the rinsing water, it is possible to prevent the rinsing liquid from becoming acidic and causing the steel plate surface to rust and turn yellow, and the effect of pickling on the steel strip can be further controlled.

[0048] In some optional embodiments, drying includes: drying with hot air, and the hot air temperature is 80°C-150°C.

[0049] In a second aspect, an embodiment of the present application provides a NM300TP wear-resistant steel, which is prepared by the preparation method of the NM300TP wear-resistant steel of the first aspect.

[0050] According to the embodiment of the present application, the NM300TP wear-resistant steel has good surface quality, the red oxide on the surface is removed, and no rust occurs within a certain period of time.

[0051] Example

[0052] The following examples describe the disclosure of the present application in more detail, and these examples are intended for illustrative purposes only, as it will be apparent to those skilled in the art that various modifications and variations may be made within the scope of the disclosure of the present application. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0053] Example 1

[0054] The present application embodiment provides a method for preparing NM300TP wear-resistant steel, the method comprising:

[0055] The rolled NM300TP steel coil is pickled in 1# pickling tank, 2# pickling tank, 3# pickling tank, 4# pickling tank and 5# pickling tank at a pickling speed of 60m / min to obtain a pickled steel strip, wherein the NM300TP steel coil includes the following chemical elements by mass percentage: C: 0.10%-0.16%, Si: 1.0%-1.5%, Mn: 1.5%-2.0%, P≤0.020%, S≤0.005%, Als: 0.4%-0.6%, Ti≤0.030%, and the remainder is Fe and other inevitable impurities. The temperature of the pickling acid solution is 80°C, and the surface of the NM300TP steel coil includes iron oxide scale; the thickness of the NM300TP steel coil is 4mm; the surface of the NM300TP steel coil includes iron oxide scale of 10μm-20μm. The acid includes hydrochloric acid;

[0056] The acid concentrations in the 1# pickling tank and the 2# pickling tank are 50 g / L respectively; the acid concentration in the 3# pickling tank is 100 g / L; the acid concentration in the 4# pickling tank is 150 g / L; and the acid concentration in the 5# pickling tank is 200 g / L.

[0057] The pickled steel strip is rinsed, squeezed and dried at a speed of 40m / min to obtain NM300TP wear-resistant steel, wherein the rinsing includes 1# rinsing tank to 5# rinsing tank; the conductivity of the rinsing solution of 1#-4# rinsing is 500μs / cm, and the water temperature of the rinsing solution is 30℃-90℃; 1# rinsing tank, the pH value of the rinsing solution of 1# rinsing tank is 1.5. The rinsing water in 5# rinsing tank meets the requirements of conductivity less than 2.5us / cm, pH 6-8, chloride ion 0.5-1.5mg / L, sodium ion 1-10ug / L, and silicon dioxide 10-50ug / L. The roller pressure of the squeezed steel strip is 0.6MPa, and hot air is used for drying, and the hot air temperature is 100℃.

[0058] Example 2

[0059] The difference between this embodiment and embodiment 1-1 is that the rolled NM300TP steel coil is pickled at a pickling speed of 80 m / min. The acid concentrations in the 1# pickling tank and the 2# pickling tank are 80 g / L respectively; the acid concentration in the 3# pickling tank is 150 g / L; the acid concentration in the 4# pickling tank is 160 g / L; and the acid concentration in the 5# pickling tank is 150 g / L.

[0060] Example 3

[0061] The difference between this embodiment and embodiment 1-1 is that the rolled NM300TP steel coil is pickled at a pickling speed of 40 m / min. The acid concentrations in the 1# pickling tank and the 2# pickling tank are 40 g / L respectively; the acid concentration in the 3# pickling tank is 80 g / L; the acid concentration in the 4# pickling tank is 100 g / L; and the acid concentration in the 5# pickling tank is 120 g / L.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that the pickling speed of the rolled NM300TP steel coil is 120 m / min.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 1 is that the pickling speed of the rolled NM300TP steel coil is 10 m / min.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 is that the acid concentrations in the 1# pickling tank and the 2# pickling tank are 180 g / L respectively; the acid concentration in the 3# pickling tank is 100 g / L; the acid concentration in the 4# pickling tank is 60 g / L; and the acid concentration in the 5# pickling tank is 50 g / L.

[0068] Comparative Example 4

[0069] The difference between this comparative example and Example 1 is that the temperature of the acid solution is 40°C.

[0070] Comparative Example 5

[0071] The difference between this comparative example and Example 1 is that the conductivity of the rinsing solution is 140 μs / cm.

[0072] Comparative Example 6

[0073] The difference between this comparative example and Example 1 is that no squeezing process is provided.

[0074] Test Section

[0075] The surfaces of the wear-resistant steels prepared in the examples and comparative examples were tested by experienced inspectors to determine the amount of red residue on the surfaces of the wear-resistant steels.

[0076] Yield = Wear-resistant steel quality after drying / NM300TP steel coil quality after rolling

[0077] The pickled and dried wear-resistant steel is placed in a room at room temperature with a humidity of 50%. The time until 50% of the area of ​​the dried wear-resistant steel is rusted is calculated.

[0078] Table 1 Detection structure of the embodiment and the comparative example

[0079]

[0080]

[0081] The above measured performance parameters are taken as average values.

[0082] Figure 1 The figure shows the appearance of the steel plate after pickling in Comparative Example 1 of the present application. Figure 2 The figure shows the appearance of the wear-resistant steel after pickling of Example 1 of the present application. Figure 1 and Figure 2 It can be seen from the comparison that the pickling method of Example 1 more comprehensively removes the red rust on the surface of the steel plate than that of Comparative Example 1.

[0083] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto, and any familiarity with the present technology or replacement should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing NM300TP wear-resistant steel, characterized in that: include: The rolled NM300TP steel coil is sequentially passed through a 1# pickling tank to a 5# pickling tank at a speed of 20 m / min-100 m / min for pickling to obtain a pickled steel strip, wherein the NM300TP steel coil comprises the following chemical elements by mass percentage: C: 0.10%-0.16%, Si: 1.0%-1.5%, Mn: 1.5%-2.0%, P≤0.020%, S≤0.005%, Als: 0.4%-0.6%, Ti≤0.030%, and the remainder is Fe and other inevitable impurities, the pickling acid solution temperature is 60°C-100°C, the pickling acid concentration is 30g / L-300g / L, and the surface of the NM300TP steel coil comprises iron oxide scale; The pickled steel strip is rinsed, squeezed and dried to obtain the NM300TP wear-resistant steel, wherein the squeezing roller pressure is 0.1 MPa-0.8 MPa.

2. The production method according to claim 1, characterized in that The acid concentrations in 1# pickling tank and 2# pickling tank are 30g / L-100g / L respectively; the acid concentration in 3# pickling tank is 50g / L-180g / L; the acid concentration in 4# pickling tank is 50g / L-180g / L; the acid concentration in 5# pickling tank is 100g / L-300g / L.

3. The production method according to claim 1, characterized in that The thickness of the NM300TP steel coil is 2mm-6mm.

4. The production method according to any one of claims 1 to 3, characterized in that The conductivity of the rinsing solution is 200 μs / cm-800 μs / cm, and the water temperature of the rinsing solution is 30° C.-90° C.

5. The production method according to any one of claims 1 to 3, characterized in that: The rinsing includes a 1# rinsing tank, and the pH value of the rinsing liquid in the 1# rinsing tank is 1.5 to 5.

0.

6. The production method according to any one of claims 1 to 3, characterized in that: The rinsing includes 1# rinsing tank to 5# rinsing tank.

7. The production method according to any one of claims 1 to 3, characterized in that: The pickled steel strip is rinsed at a speed of 20m / min-100m / min.

8. The production method according to any one of claims 1 to 3, characterized in that: The surface of the NM300TP steel coil includes iron oxide scale of 10 μm-20 μm.

9. The production method according to any one of claims 1 to 3, characterized in that: The acid includes hydrochloric acid, and the rinsing water in the 5# rinsing tank meets the following conditions: conductivity is less than 2.5us / cm, pH is 6-8, chloride ions are 0.5-1.5mg / L, sodium ions are 1-10ug / L, and silicon dioxide is 10-50ug / L.

10. A NM300TP wear-resistant steel, characterized in that: The steel is prepared by the preparation method of NM300TP wear-resistant steel according to any one of claims 1 to 9.

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