阅读说明：本技术 一种高铝耐候钢及其制备方法 (High-aluminum weathering steel and preparation method thereof ) 是由 刘日平 唐轶浩 马巍 王飞 张国峰 景勤 马明臻 张新宇 于 2021-09-07 设计创作，主要内容包括：本发明属于合金技术领域,特别涉及一种高铝耐候钢及其制备方法。本发明提供的高铝耐候钢,以质量百分含量计,包括以下元素：Al4～11％、Si0.2～2％、P0.01～0.35％、Cu0.15～0.5％、Cr0.2～1.5％、Ni0.1～5.5％和余量的Fe。在本发明中,Al元素作为耐候钢的强化元素,通过固溶强化的方式溶入耐候钢的基体中,在拉伸时通过阻碍位错运动提升位错运动的阻力,有效提升拉伸强度；同时,Al在耐候钢中的固溶强化作用强,有利于在显著提高耐候钢的强度同时有效细化耐候钢表面的锈层产物。实施例表明,本发明提供的高铝耐候钢具有良好的强度、塑性和优异的耐候性。(The invention belongs to the technical field of alloys, and particularly relates to high-aluminum weathering steel and a preparation method thereof. The high-aluminum weathering steel provided by the invention comprises the following elements in percentage by mass: 4-11% of Al, 0.2-2% of Si, 0.01-0.35% of P, 0.15-0.5% of Cu, 0.2-1.5% of Cr, 0.1-5.5% of Ni and the balance of Fe. In the invention, Al element is taken as a strengthening element of the weathering steel, is dissolved in a matrix of the weathering steel in a solid solution strengthening mode, and improves the resistance of dislocation movement by blocking the dislocation movement during stretching, thereby effectively improving the tensile strength; meanwhile, the Al has strong solid solution strengthening effect in the weathering steel, which is beneficial to effectively refining rust layer products on the surface of the weathering steel while obviously improving the strength of the weathering steel. The embodiment shows that the high-aluminum weathering steel provided by the invention has good strength and plasticity and excellent weather resistance.)

1. The high-aluminum weathering steel is characterized by comprising the following elements in percentage by mass:

4-11% of Al, 0.2-2% of Si, 0.01-0.35% of P, 0.15-0.5% of Cu, 0.2-1.5% of Cr, 0.1-5.5% of Ni and the balance of Fe.

2. The high-aluminum weathering steel according to claim 1, further comprising one or more of the following elements in mass percent:

mn, C, Mo, Ti, Nb and V.

3. The high aluminum weathering steel of claim 1 wherein the structure of the high aluminum weathering steel includes ferrite and/or austenite.

4. The high aluminum weathering steel according to claim 1 or 3 wherein the high aluminum weathering steel has a structure with a width of 10 to 750 μm.

5. The method for preparing the high-aluminum weathering steel according to any of claims 1 to 4, characterized by comprising the steps of:

smelting a raw material of high-aluminum weathering steel and then cooling to obtain an ingot;

and sequentially carrying out preheating, heat preservation and hot rolling on the cast ingot to obtain the high-aluminum weathering steel.

6. The preparation method according to claim 5, wherein the smelting temperature is 2200-2600 ℃.

7. The preparation method according to claim 5, wherein the preheating and heat preservation temperature is 1000-1150 ℃, and the heat preservation time is 20-60 min.

8. The production method according to claim 5, wherein the hot rolling is performed at a start rolling temperature of 1000 to 1150 ℃; the total deformation amount of the hot rolling is 65-70%.

9. The method according to claim 8, wherein the hot rolling is performed for 5 to 6 passes, and the amount of deformation per pass is independently 10 to 14%.

10. The production method according to claim 8 or 9, wherein heat holding is performed between two passes in the hot rolling; the temperature of heat preservation is independently 1000-1150 ℃, and the time is independently 4-6 min.

Technical Field

The invention belongs to the technical field of alloys, and particularly relates to high-aluminum weathering steel and a preparation method thereof.

Background

The weathering steel, i.e. the atmospheric corrosion resistant steel, is a series of low alloy steels between ordinary steel and stainless steel, is made of plain carbon steel with a small amount of corrosion resistant elements such as copper, nickel and the like added, has the characteristics of toughness, ductility, fatigue resistance and the like of high-quality steel, has the characteristics of rust resistance, corrosion resistance, long service life, thinning, consumption reduction and the like of members, and is widely applied to steel structures of railways, vehicles, bridges and the like which are exposed to atmospheric environment for a long time.

With the development of industry, a large amount of greenhouse gas is discharged into the atmosphere, which makes the atmosphere facing the weathering steel more severely corroded. The weather resistance and mechanical property of the traditional weathering steel (such as Q355NH) can not meet the increasingly severe service requirements.

Disclosure of Invention

In view of this, the invention aims to provide high-aluminum weathering steel and a preparation method thereof.

In order to achieve the purpose of the invention, the invention provides the following technical scheme:

the invention provides high-aluminum weathering steel which comprises the following elements in percentage by mass:

4-11% of Al, 0.2-2% of Si, 0.01-0.35% of P, 0.15-0.5% of Cu, 0.2-1.5% of Cr, 0.1-5.5% of Ni and the balance of Fe.

Preferably, the paint also comprises one or more of the following elements in percentage by mass:

mn, C, Mo, Ti, Nb and V.

Preferably, the structure of the high-aluminum weathering steel includes ferrite and/or austenite.

Preferably, the structure width of the high-aluminum weathering steel is 10 to 750 μm.

The invention also provides a preparation method of the high-aluminum weathering steel, which comprises the following steps:

smelting a raw material of high-aluminum weathering steel and then cooling to obtain an ingot;

and sequentially carrying out preheating, heat preservation and hot rolling on the cast ingot to obtain the high-aluminum weathering steel.

Preferably, the smelting temperature is 2200-2600 ℃.

Preferably, the preheating and heat preservation temperature is 1000-1150 ℃, and the heat preservation time is 20-60 min.

Preferably, the initial rolling temperature of the hot rolling is 1000-1150 ℃; the total deformation amount of the hot rolling is 65-70%.

Preferably, the hot rolling passes are 5-6, and the deformation of each pass is 10-14%.

Preferably, heat preservation is carried out between two times in the hot rolling; the temperature of heat preservation is independently 1000-1150 ℃, and the time is independently 4-6 min.

The invention provides high-aluminum weathering steel which comprises the following elements in percentage by mass: 4-11% of Al, 0.2-2% of Si, 0.01-0.35% of P, 0.15-0.5% of Cu, 0.2-1.5% of Cr, 0.1-5.5% of Ni and the balance of Fe. In the invention, Al element is taken as a strengthening element of the weathering steel, is dissolved in a matrix of the weathering steel in a solid solution strengthening mode, and improves the resistance of dislocation movement by blocking the dislocation movement during stretching, thereby effectively improving the tensile strength; meanwhile, the Al has strong solid solution strengthening effect in the weathering steel, so that the strength of the weathering steel is obviously improved, and rust layer products on the surface of the weathering steel are effectively refined; si improves the elasticity of the weathering steel and simultaneously enhances the corrosion resistance of the weathering steel under natural conditions; the P has strong solid solution strengthening effect, is used together with Cu, is beneficial to the enrichment of Cu element in a generated rust layer, and improves the capability of the weathering steel for resisting external erosion, namely improves the atmospheric corrosion resistance of the weathering steel; cu is beneficial to expanding an austenite phase region, and is beneficial to improving the atmospheric corrosion resistance under the synergistic effect with P; cr improves the strength and hardness of the weathering steel; the Ni refines the plasticity and toughness of the weathering steel and improves the corrosion resistance of the weathering steel. In conclusion, under the synergistic coordination of all elements, the high-aluminum weathering steel provided by the invention has the characteristics of high strength and excellent weathering resistance.

Further, Mn has a strong solid solution strengthening effect on the weathering steel, and is beneficial to expanding an austenite phase region by forming austenite, and the austenite has an FCC structure, numerous slip systems and good denaturation capability and is beneficial to improving the plasticity of the weathering steel; c is beneficial to expanding an austenite phase region and improving the strength and hardness of the weathering steel; mo is beneficial to refining the crystal grains of the weathering steel and improving the strength and hardness of the weathering steel; ti is beneficial to reducing the aging sensitivity and cold brittleness of the weathering steel and refining crystal grains; nb is beneficial to improving the strength of the weathering steel; v is beneficial to refining crystal grains and improving the strength and toughness of the weathering steel.

The test result of the embodiment shows that the high-aluminum weathering steel provided by the invention has the advantages that the yield strength is 424.59-521.27 MPa, the tensile strength is 552.26-725.34 MPa, the elongation is 32.43-51.91%, and the high-aluminum weathering steel has good strength and plasticity; the weight of the mixture is increased to 1.20 to 2.81mg/cm in 480h sodium chloride aqueous solution²And has excellent weather resistance.

The invention also provides a preparation method of the high-aluminum weathering steel, which comprises the following steps: smelting a raw material of high-aluminum weathering steel and then cooling to obtain an ingot; and sequentially carrying out preheating, heat preservation and hot rolling on the cast ingot to obtain the high-aluminum weathering steel. In the invention, the crystal grains are refined through violent deformation in the hot rolling process and are elongated along the rolling direction, which is beneficial to effectively improving the mechanical property of the high-aluminum weathering steel on the basis of ensuring the weather resistance. The method provided by the invention is simple, and after hot rolling is finished, subsequent treatments such as annealing and the like are not needed, so that the method is simple and easy to implement.

Drawings

FIG. 1 is a metallographic optical micrograph of a high aluminum weathering steel obtained in example 1;

FIG. 2 is a metallographic optical micrograph of the high aluminum weathering steel obtained in example 2;

FIG. 3 is a metallographic optical micrograph of a high aluminum weathering steel obtained in example 3;

FIG. 4 is a metallographic optical micrograph of a high aluminum weathering steel obtained in example 4;

FIG. 5 is a metallographic optical micrograph of a high aluminum weathering steel obtained in example 5;

fig. 6 is a dimensional diagram of a uniaxial tensile specimen for tensile property testing.

Detailed Description

The invention provides high-aluminum weathering steel which comprises the following elements in percentage by mass:

4-11% of Al, 0.2-2% of Si, 0.01-0.35% of P, 0.15-0.5% of Cu, 0.2-1.5% of Cr, 0.1-5.5% of Ni and the balance of Fe.

In the invention, the high-aluminum weathering steel comprises, by mass, 4-11% of Al, preferably 4.5-10.5%, more preferably 5-10%, and still more preferably 5.5-9.5%. In the invention, Al element is taken as a strengthening element of the weathering steel, is dissolved in a matrix of the weathering steel in a solid solution strengthening mode, and improves the resistance of dislocation movement by blocking the dislocation movement during stretching, thereby effectively improving the tensile strength; meanwhile, the Al has strong solid solution strengthening effect in the weathering steel, and is beneficial to refining rust products on the surface of the weathering steel in an atmospheric corrosion environment.

In the invention, the high-aluminum weathering steel comprises 0.2-2% of Si, preferably 0.22-1.8%, more preferably 0.25-1.6%, and even more preferably 0.3-1.5% by mass. In the invention, Si is beneficial to improving the elasticity of the weathering steel and is also beneficial to enhancing the corrosion resistance of the weathering steel under natural conditions.

In the invention, the high-aluminum weather-resistant steel comprises 0.01-0.35% of P, preferably 0.02-0.32%, more preferably 0.03-0.30%, and even more preferably 0.05-0.25% by mass. In the invention, the P has strong solid solution strengthening effect, is used together with Cu, is beneficial to the enrichment of Cu element in the generated rust layer, and improves the capability of the weathering steel for resisting external erosion, namely the atmospheric corrosion resistance of the weathering steel.

In the invention, the high-aluminum weathering steel comprises, by mass, 0.15-0.5% of Cu, preferably 0.18-0.48%, more preferably 0.2-0.45%, and even more preferably 0.25-0.42%. In the invention, Cu is beneficial to expanding an austenite phase region, and is beneficial to improving the atmospheric corrosion resistance by the synergistic effect with P.

In the invention, the high-aluminum weathering steel comprises 0.2-1.5% of Cr, preferably 0.25-1.4%, more preferably 0.3-1.3%, and even more preferably 0.35-1.2% by mass. In the invention, Cr is beneficial to improving the strength and hardness of the weathering steel.

In the invention, the high-aluminum weathering steel comprises 0.1-5.5% of Ni, preferably 0.5-5.3%, more preferably 1-5.2%, and preferably 2-5% by mass. In the invention, Ni is beneficial to refining the plasticity and toughness of the weathering steel and simultaneously beneficial to improving the corrosion resistance of the weathering steel.

In the present invention, the high aluminum weathering steel preferably further includes one or more of the following elements in mass percent: mn, C, Mo, Ti, Nb and V.

In the present invention, when the high-aluminum weathering steel contains Mn, the high-aluminum weathering steel preferably further contains Mn of more than 0 and 35% by mass, more preferably 2 to 33%, still more preferably 4 to 31%, and further preferably 5 to 30%. In the invention, Mn has stronger solid solution strengthening effect on the weathering steel, and is beneficial to expanding an austenite phase region by forming austenite, and the austenite has an FCC structure, a plurality of slip systems and good denaturation capability, and is beneficial to improving the plasticity of the weathering steel.

In the present invention, when the high-aluminum weathering steel contains C, the high-aluminum weathering steel preferably further contains more than 0 and 0.6% by mass or less of C, more preferably 0.01 to 0.58%, still more preferably 0.03 to 0.55%, and further preferably 0.05 to 0.45%. In the invention, C is beneficial to expanding an austenite phase region and improving the strength and hardness of the weathering steel.

In the present invention, when the high-aluminum weathering steel contains Mo, the high-aluminum weathering steel preferably further contains Mo in an amount of more than 0% and not more than 1.5% by mass, more preferably 0.1 to 1.4%, still more preferably 0.15 to 1.3%, and still more preferably 0.2 to 1%. In the invention, Mo is beneficial to refining the crystal grains of the weathering steel and improving the strength and hardness of the weathering steel.

In the present invention, when the high-aluminum weathering steel contains Ti, the high-aluminum weathering steel preferably further contains more than 0 and 0.15% by mass or less of Ti, more preferably 0.01 to 0.14%, still more preferably 0.02 to 0.13%, and still more preferably 0.03 to 0.12%. In the invention, Ti is beneficial to reducing the aging sensitivity and cold brittleness of the weathering steel and refining crystal grains.

In the present invention, when the high-aluminum weathering steel contains Nb, the high-aluminum weathering steel preferably further contains more than 0 and 0.15% by mass or less of Nb, more preferably 0.01 to 0.14%, still more preferably 0.02 to 0.13%, and still more preferably 0.03 to 0.12%. In the present invention, Nb is advantageous for improving the strength of the weathering steel.

In the present invention, when the high-aluminum weathering steel contains V, the high-aluminum weathering steel preferably further contains V in an amount of greater than 0% and not greater than 0.15%, more preferably 0.01 to 0.14%, still more preferably 0.02 to 0.13%, and still more preferably 0.03 to 0.12% by mass. In the invention, V is beneficial to refining crystal grains and improving the strength and toughness of the weathering steel.

In the invention, the high-aluminum weathering steel comprises the balance of Fe in percentage by mass.

In the present invention, the structure of the high aluminum weathering steel preferably includes ferrite and/or austenite.

In the invention, the width of the structure of the high-aluminum weathering steel is preferably 10 to 750 μm, and more preferably 20 to 700 μm.

The invention also provides a preparation method of the high-aluminum weathering steel, which comprises the following steps:

smelting a raw material of high-aluminum weathering steel and then cooling to obtain an ingot;

and sequentially carrying out preheating, heat preservation and hot rolling on the cast ingot to obtain the high-aluminum weathering steel.

In the present invention, unless otherwise specified, each component in the preparation method is a commercially available product well known to those skilled in the art.

The method comprises the steps of smelting raw materials of the high-aluminum weathering steel and then cooling the smelted raw materials to obtain an ingot.

The specific sources and addition of the raw materials of the high-aluminum weathering steel are not specially limited, so that the high-aluminum weathering steel meeting the chemical component requirements is obtained. Specifically, according to the composition of the actually obtained raw material alloy, the dosage of each raw material alloy is reasonably adjusted, and the components and dosage of the intermediate alloy are matched to obtain the high-aluminum weathering steel meeting the chemical composition. In the present invention, the raw material of the high aluminum weathering steel preferably includes industrial pure iron, pure aluminum, silicon particles, ferrophosphorus, pure copper, chromium particles and pure nickel, and preferably further includes one or more of electrolytic manganese flakes, carbon particles, pure molybdenum, pure titanium, pure niobium and pure vanadium.

In the present invention, the melting is preferably: mixing and melting raw materials of the high-aluminum weathering steel, cooling, turning over the obtained alloy cast ingot, melting, cooling, and repeating for multiple times to obtain the cast ingot.

In the invention, the melting temperature is preferably 2200-2600 ℃, more preferably 2200-2550 ℃, still more preferably 2200-2500 ℃, and further preferably 2200-2400 ℃. In the present invention, the number of times of melting is preferably not less than 6, and more preferably 7 to 9. In the invention, the time for each melting is preferably 2.5-5 min, more preferably 3-4.5 min, and still more preferably 3.5-4 min.

In the present invention, the melting is preferably vacuum arc melting. In the present invention, the melting apparatus is preferably a vacuum arc furnace. In the invention, the vacuum degree of the vacuum arc melting is preferably 0.03-0.06 MPa, and more preferably 0.035-0.055 MPa. In the present invention, the melting is preferably performed under an ionized gas condition. In the present invention, the ionized gas is preferably argon gas. According to the invention, the cavity of the smelting equipment is preferably vacuumized and then ionized gas is introduced. In the present invention, the evacuation is preferably performed to 3X 10^-3～8×10^-3Pa. In the invention, the introduction amount of the ionized gas is based on the usage amount of the ionized gas for electric arc melting. The invention adopts the method of firstly vacuumizing and then introducing the ionized gas, so that the ionized gas can be provided, and simultaneously, the raw material oxidation during smelting can be avoided.

Before smelting, the raw materials of the high-aluminum weathering steel are preferably cleaned. In the present invention, the liquid medium in the washing is preferably absolute ethanol. In the present invention, the cleaning method is preferably ultrasonic cleaning; the ultrasonic cleaning is not particularly limited in the present invention, and may be performed by ultrasonic cleaning known to those skilled in the art.

After washing, the present invention preferably air-dries the resulting cleaning material.

After obtaining the cast ingot, sequentially preheating, preserving heat and hot rolling the cast ingot to obtain the high-aluminum weathering steel.

In the invention, the temperature of preheating and heat preservation is preferably 1000-1150 ℃, more preferably 1015-1135 ℃, and further preferably 1025-1125 ℃; the heat preservation time is preferably 20-60 min, more preferably 25-55 min, and still more preferably 30-50 min. In the invention, the temperature of the preheating and heat preservation is preferably obtained by raising the temperature of room temperature; the heating rate is preferably 5-15 ℃/min, more preferably 7-13 ℃/min, and still more preferably 9-11 ℃/min. In the invention, the preheating and heat-preserving device is preferably a muffle furnace.

In the invention, the initial rolling temperature of the hot rolling is preferably 1000-1150 ℃, more preferably 1015-1135 ℃, and still more preferably 1025-1125 ℃. In the present invention, the total deformation amount of the hot rolling is preferably 65 to 70%, more preferably 65.5 to 79.5%. In the invention, the number of hot rolling passes is preferably 5-6; the amount of deformation per pass is preferably independently 10 to 14%, more preferably 11 to 13%. In the present invention, the rolling reduction per pass in the hot rolling is preferably 1.5 to 2.5mm, more preferably 1.7 to 2.3mm, and still more preferably 1.9 to 2.1 mm. In the present invention, the thickness of the high-aluminum weathering steel plate obtained after hot rolling is preferably 4 to 5mm, more preferably 4.2 to 4.8mm, and still more preferably 4.4 to 4.6 mm. In the present invention, the hot rolling apparatus is preferably a twin roll synchronous rolling mill; in the embodiment of the invention, the hot rolling equipment is preferably a 200-type double-roller synchronous rolling mill.

The present invention preferably maintains the temperature between two passes in the hot rolling. In the invention, the temperature of heat preservation is preferably 1000-1150 ℃, more preferably 1015-1135 ℃, and further preferably 1025-1125 ℃; the time is preferably 4 to 6min independently, and more preferably 4.5 to 5.5 min. In the present invention, the heat-retaining device is preferably a muffle furnace. In the present invention, the alloy ingot undergoes severe extrusion deformation during hot rolling, so that grains are elongated in the rolling direction and a large amount of distortion energy is generated to be stored inside; in the heat preservation process between each hot rolling, the distortion energy is released, so that the recrystallization speed is improved, the crystal grains are refined, and the strength, the plasticity and the toughness of the high-aluminum weathering steel are improved.

In the invention, the combined action of preheating, heat preservation and hot rolling is beneficial to eliminating the internal defect generated by the over-high cooling speed after smelting, refining the grain structure, accumulating a large amount of dislocation in the structure and improving the mechanical property.

In the invention, the high-aluminum weathering steel has good mechanical properties and excellent weather resistance, and meets the use requirements of steel materials for industrial structures.

In order to further illustrate the present invention, the following examples are provided to describe a high aluminum weathering steel and its preparation method in detail, but they should not be construed as limiting the scope of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The high-aluminum weathering steel comprises the following chemical components:

fe-2Mn-5Al-0.3Si-0.05P-0.15Cu-0.15Ni-0.2Cr, namely Mn 2%, Al 5%, Si 0.3%, P0.05%, Cu 0.15%, Ni 0.15%, Cr 0.2%, and the balance of Fe in percentage by mass;

according to the chemical composition of the designed high-aluminum weathering steel, 92g of industrial pure iron, 2g of electrolytic manganese sheets, 5g of pure aluminum, 0.3g of silicon particles, 0.2g of ferrophosphorus, 0.15g of pure copper, 0.15g of pure nickel and 0.2g of chromium particles are immersed in absolute ethyl alcohol, cleaned by ultrasonic waves and dried in the air;

mixing the obtained clean raw materials, placing in a water-cooled copper crucible of a vacuum arc furnace at a vacuum degree of 5 × 10^{- 3}Carrying out vacuum arc melting under the conditions of Pa and argon with the pressure of 0.06MPa, wherein the melting temperature is 2400 ℃, the working current in the melting process is 500A, after each melting is finished, cooling alloy liquid, overturning the obtained alloy ingot, then melting again, melting for 4min each time, carrying out co-melting for 7 times, and cooling to obtain an ingot;

and placing the obtained cast ingot into a muffle furnace, heating to 1050 ℃ at the speed of 10 ℃/min, preserving heat for 30min, taking out, carrying out hot rolling on a 200-type double-roller synchronous rolling mill, wherein the starting rolling temperature of the hot rolling is 1050 ℃, the rolling passes of the hot rolling are 6 times, the reduction of each pass is 2mm, the deformation is 11%, the total deformation is 66%, and preserving heat for 5min at 1050 ℃ in the muffle furnace between the rolling passes of each pass to obtain the high-aluminum weather-resistant steel with the thickness of 4.5 mm.

Example 2

The high-aluminum weathering steel comprises the following chemical components:

fe-8Mn-6.5Al-0.1C-0.3Si-0.05P-0.3Cu-0.5Ni-0.2Cr-0.05Ti, namely Mn 8%, Al 6.5%, C0.1%, Si 0.3%, P0.05%, Cu 0.3%, Ni 0.5%, Cr 0.2%, Ti 0.05% and the balance of Fe in percentage by mass;

according to the chemical components of the designed high-aluminum weathering steel, 83.85g of industrial pure iron, 8g of electrolytic manganese sheets, 6.5 g of pure aluminum, 0.1g of carbon particles, 0.3g of silicon particles, 0.2g of ferrophosphorus, 0.3g of pure copper, 0.5g of pure nickel, 0.2g of chromium particles and 0.05g of pure titanium are immersed in absolute ethyl alcohol, cleaned by ultrasonic waves and dried in the air;

mixing the obtained clean raw materials, placing in a water-cooled copper crucible of a vacuum arc furnace at a vacuum degree of 5 × 10^{- 3}Carrying out vacuum arc melting under the conditions of Pa and argon with the pressure of 0.06MPa, wherein the melting temperature is 2400 ℃, the working current in the melting process is 500A, after each melting is finished, cooling alloy liquid, overturning the obtained alloy ingot, then melting again, melting for 4min each time, carrying out co-melting for 7 times, and cooling to obtain an ingot;

and placing the obtained cast ingot into a muffle furnace, heating to 1050 ℃ at the speed of 10 ℃/min, preserving heat for 30min, taking out, carrying out hot rolling on a 200-type double-roller synchronous rolling mill, wherein the starting rolling temperature of the hot rolling is 1050 ℃, the rolling passes of the hot rolling are 6 times, the reduction of each pass is 2mm, the deformation is 11%, the total deformation is 66%, and preserving heat for 5min at 1050 ℃ in the muffle furnace between the rolling passes of each pass to obtain the high-aluminum weather-resistant steel with the thickness of 4.5 mm.

Example 3

The high-aluminum weathering steel comprises the following chemical components:

fe-15Mn-8Al-0.25C-0.45Si-0.1P-0.35Cu-1Ni-0.5Cr-0.05Ti-0.05Nb, namely, according to the mass percentage, Mn 15%, Al 8%, C0.25%, Si 0.45%, P0.1%, Cu 0.35%, Ni 1%, Cr 0.5%, Ti 0.05%, Nb 0.05%, and the balance of Fe;

according to the chemical composition of the designed high-aluminum weathering steel, 73.95g of industrial pure iron, 15g of electrolytic manganese sheets, 8g of pure aluminum, 0.25g of carbon particles, 0.45g of silicon particles, 0.4g of ferrophosphorus, 0.35g of pure copper, 1g of pure nickel, 0.5g of chromium particles, 0.05g of pure titanium and 0.05g of pure niobium are immersed in absolute ethyl alcohol, cleaned by ultrasonic waves and dried in the air;

mixing the obtained clean raw materials, placing in a water-cooled copper crucible of a vacuum arc furnace at a vacuum degree of 5 × 10^{- 3}Carrying out vacuum arc melting under the conditions of Pa and argon with the pressure of 0.06MPa, wherein the melting temperature is 2400 ℃, the working current in the melting process is 500A, after each melting is finished, cooling alloy liquid, overturning the obtained alloy ingot, then melting again, melting for 4min each time, carrying out co-melting for 7 times, and cooling to obtain an ingot;

and placing the obtained cast ingot into a muffle furnace, heating to 1050 ℃ at the speed of 10 ℃/min, preserving heat for 30min, taking out, carrying out hot rolling on a 200-type double-roller synchronous rolling mill, wherein the starting rolling temperature of the hot rolling is 1050 ℃, the rolling passes of the hot rolling are 6 times, the reduction of each pass is 2mm, the deformation is 11%, the total deformation is 66%, and preserving heat for 5min at 1050 ℃ in the muffle furnace between the rolling passes of each pass to obtain the high-aluminum weather-resistant steel with the thickness of 4.5 mm.

Example 4

The high-aluminum weathering steel comprises the following chemical components:

fe-22Mn-9Al-0.3C-0.45Si-0.15P-0.35Cu-2Ni-0.75Cr-0.1Ti-0.05Nb, namely Mn 22%, Al 9%, C0.3%, Si 0.45%, P0.15%, Cu 0.35%, Ni 2%, Cr 0.75%, Ti 0.1%, Nb 0.05% and the balance of Fe in percentage by mass;

according to the chemical composition of the designed high-aluminum weathering steel, 64.4g of industrial pure iron, 22g of electrolytic manganese sheets, 9g of pure aluminum, 0.3g of carbon particles, 0.45g of silicon particles, 0.6g of ferrophosphorus, 0.35g of pure copper, 2g of pure nickel, 0.75g of chromium particles, 0.1g of pure titanium and 0.05g of pure niobium are immersed in absolute ethyl alcohol, cleaned by ultrasonic waves and dried in the air;

mixing the obtained clean raw materials, placing in a water-cooled copper crucible of a vacuum arc furnace at a vacuum degree of 5 × 10^{- 3}Carrying out vacuum arc melting under the conditions of Pa and argon with the pressure of 0.06MPa, wherein the melting temperature is 2400 ℃, the working current in the melting process is 500A, after each melting is finished, cooling alloy liquid, overturning the obtained alloy ingot, then melting again, melting for 4min each time, carrying out co-melting for 7 times, and cooling to obtain an ingot;

and placing the obtained cast ingot into a muffle furnace, heating to 1050 ℃ at the speed of 10 ℃/min, preserving heat for 30min, taking out, carrying out hot rolling on a 200-type double-roller synchronous rolling mill, wherein the starting rolling temperature of the hot rolling is 1050 ℃, the rolling passes of the hot rolling are 6 times, the reduction of each pass is 2mm, the deformation is 11%, the total deformation is 66%, and preserving heat for 5min at 1050 ℃ in the muffle furnace between the rolling passes of each pass to obtain the high-aluminum weather-resistant steel with the thickness of 4.5 mm.

Example 5

The high-aluminum weathering steel comprises the following chemical components:

fe-32Mn-10Al-0.3C-0.5Si-0.2P-0.4Cu-3Ni-0.75Cr-0.5Mo-0.1Ti-0.1Nb-0.1V, namely Mn 32%, Al 10%, C0.3%, Si 0.5%, P0.2%, Cu 0.4%, Ni 3%, Cr 0.75%, Mo 0.5%, Ti 0.1%, Nb 0.1%, V0.1% and the balance of Fe in percentage by mass;

according to the chemical composition of the designed high-aluminum weathering steel, 51.45g of industrial pure iron, 32g of electrolytic manganese sheets, 10g of pure aluminum, 0.3g of carbon particles, 0.5g of silicon particles, 0.8g of ferrophosphorus, 0.4g of pure copper, 3g of pure nickel, 0.75g of chromium particles, 0.5g of pure molybdenum, 0.1g of pure titanium, 0.1g of pure niobium and 0.1g of pure vanadium are immersed in absolute ethyl alcohol, cleaned by ultrasonic waves and dried in the air;

mixing the obtained clean raw materials, placing in a water-cooled copper crucible of a vacuum arc furnace at a vacuum degree of 5 × 10^{- 3}Carrying out vacuum arc melting under the conditions of Pa and argon with the pressure of 0.06MPa, wherein the melting temperature is 2400 ℃, the working current in the melting process is 500A, after each melting is finished, cooling alloy liquid, overturning the obtained alloy ingot, then melting again, melting for 4min each time, carrying out co-melting for 7 times, and cooling to obtain an ingot;

and placing the obtained cast ingot into a muffle furnace, heating to 1050 ℃ at the speed of 10 ℃/min, preserving heat for 30min, taking out, carrying out hot rolling on a 200-type double-roller synchronous rolling mill, wherein the starting rolling temperature of the hot rolling is 1050 ℃, the rolling passes of the hot rolling are 6 times, the reduction of each pass is 2mm, the deformation is 11%, the total deformation is 66%, and preserving heat for 5min at 1050 ℃ in the muffle furnace between the rolling passes of each pass to obtain the high-aluminum weather-resistant steel with the thickness of 4.5 mm.

Metallographic optical microscopic observation is carried out on the high-aluminum weathering steel obtained in examples 1 to 5, and the obtained metallographic optical fiber graph is shown in fig. 1 to 5, wherein fig. 1 is the metallographic optical microscopic graph of the high-aluminum weathering steel obtained in example 1, fig. 2 is the metallographic optical microscopic graph of the high-aluminum weathering steel obtained in example 2, fig. 3 is the metallographic optical microscopic graph of the high-aluminum weathering steel obtained in example 3, fig. 4 is the metallographic optical microscopic graph of the high-aluminum weathering steel obtained in example 4, and fig. 5 is the metallographic optical microscopic graph of the high-aluminum weathering steel obtained in example 5.

As can be seen from fig. 1 to 5, the high-aluminum weathering steel obtained in example 1 was a pure ferrite structure; the high-aluminum weathering steel obtained in the embodiment 2 and the embodiment 3 has ferrite and austenite structures; the high-aluminum weathering steel obtained in example 4 and example 5 has a pure austenite structure; the structure grain boundary of the high-aluminum weathering steel obtained in the embodiments 1 to 5 is clearly visible, which shows that the high-aluminum weathering steel obtained under the technical scheme provided by the invention does not have the phenomenon of grain boundary blurring caused by overburning.

Comparative example 1

The high-aluminum weathering steel comprises the following chemical components:

fe-1.2Mn-0.1C-0.3Si-0.015P-0.3Cu-0.45Cr-0.3Ni-0.05V-0.05Nb, namely, according to the mass percentage, 1.2 percent of Mn, 0.1 percent of C, 0.3 percent of Si, 0.015 percent of P, 0.3 percent of Cu, 0.45 percent of Cr, 0.3 percent of Ni, 0.05 percent of V, 0.05 percent of Nb and the balance of Fe;

according to the chemical composition of the designed high-aluminum weathering steel, 92g of industrial pure iron, 2g of electrolytic manganese sheets, 5g of pure aluminum, 0.3g of silicon particles, 0.2g of ferrophosphorus, 0.15g of pure copper, 0.15g of pure nickel and 0.2g of chromium particles are immersed in absolute ethyl alcohol, cleaned by ultrasonic waves and dried in the air;

the remaining preparation method was the same as in example 1, to obtain weathering steel.

And (3) carrying out mechanical property test on the high-aluminum weathering steel obtained in the examples 1-5 and the weathering steel obtained in the comparative example 1, wherein the test method comprises the following steps: the weather-resistant steel sheet was cut into a uniaxial tensile specimen in a bone bar shape by wire cutting, and the uniaxial tensile specimen was individually tested in accordance with GBT228-2002, and the dimensional chart of the uniaxial tensile specimen is shown in FIG. 6. During the test, at least 3 uniaxial tensile specimens were cut out of the samples of each example to ensure the reproducibility of the data, and the measurement was carried out using a room-temperature uniaxial tensile test with an Instron5982 Universal Material testing machine (manufacturer: Instron, USA) whose tensile displacement was monitored all the way with an extensometer, the tensile rate being set at 5X 10^-3s^-1. The mechanical property test results of the high-aluminum weathering steel obtained in examples 1-5 and the weathering steel obtained in comparative example 1 are shown in table 1.

TABLE 1 mechanical Property test results of examples 1 to 5 and comparative example 1

As can be seen from the table 1, the high-aluminum weathering steel provided by the invention has the advantages that the yield strength is 424.59-521.27 MPa, the tensile strength is 552.26-725.34 MPa, the elongation is 32.43-51.91%, and the high-aluminum weathering steel has good strength and plasticity; compared with the weathering steel provided by the comparison document 1, the yield strength is improved by 21.57-49.25%, the tensile strength is improved by 0.47-31.96%, the elongation is improved by 21.01-93.69%, and the weathering steel has a more excellent engineering application prospect.

The high-aluminum weathering steel obtained in examples 1-5 and the weathering steel obtained in comparative example 1 were subjected to corrosion resistance tests, and the test methods were: processing the weathering steel into periodic infiltration corrosion samples with the size of 60mm multiplied by 40mm multiplied by 3mm by linear cutting, and cutting 5 samples from each weathering steel plate to ensure the repeatability of the test; the sample is ground to 800# by using sand paper, the surface of the sample is dried by blowing after cleaning, and then a periodic infiltration corrosion test box (FL-65, Wuxi Shuzo and testing apparatus Co., Ltd.) is used for carrying out the periodic infiltration corrosion test in the environment of NaCl solution with the concentration of 3.5 wt% according to GB/T19746-.

TABLE 2 test standards for periodic immersion corrosion testing

TABLE 3 Corrosion resistance test results of examples 1 to 5 and comparative example 1

	Weight gain (mg/cm)2)	Corrosion weight increasing ratio (%)
			Example 1	2.81	18.39
Example 2	2.39	15.64
			Example 3	2.04	13.15
Example 4	1.48	9.69
			Example 5	1.20	7.85
Comparative example 1	15.28	/

As can be seen from Table 3, the weight of the high-aluminum weathering steel provided by the invention is increased by 1.20-2.81 mg/cm in 480h sodium chloride aqueous solution²Comparison with comparative example 1 (weight gain of 15.28 mg/cm)²) Compared with the prior art, the high-aluminum weathering steel provided by the invention has more excellent corrosion resistance.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.