阅读说明：本技术 耐蚀无磁钢及其制备方法 (Corrosion-resistant non-magnetic steel and preparation method thereof ) 是由 李佳滨 于 2019-10-17 设计创作，主要内容包括：本发明公开了一种耐蚀无磁钢及其制备方法,该耐蚀无磁钢的化学成分按重量百分数包括：C：0.25%~0.35%,Si≤0.045%,A1：2.0%~2.5%,Mn：22.5%~25%,P≤0.04%,Mo：0.5%~2.0%,Cr：6.0%~10%,Nb≤0.5%,其余为Fe及不可避免杂质,经真空炼熔、底浇模铸与加热轧制制成。上述耐蚀无磁钢,通过添加价格较低的P、Mo与Nb等元素来代替昂贵的Ni元素,实现了制作成本的降低与镍资源的节约,同时P、Mo与Nb对无磁钢都有与Ni一致的抗腐蚀性能,其中P能提高无磁钢抗大气腐蚀的作用,Mo能提高铬系无磁钢的抗晶间腐蚀能力,Nb对铬系无磁钢有细晶强化和弥散强化作用,提高无磁钢抗高温氧化性和耐腐蚀性能,该耐蚀无磁钢实现了高性价比需求与节约镍资源需求。(The invention discloses a corrosion-resistant non-magnetic steel and a preparation method thereof, the chemical components of the corrosion-resistant non-magnetic steel comprise, by weight, 0.25% ~ 0.35.35% of C, less than or equal to 0.045% of Si, 2.0% ~ 2.5.5% of A1, 22.5% ~ 25% of Mn, less than or equal to 0.04% of P, 0.5% of Mo, ~ 2.0.0% of Mo, 6.0% of Cr, ~ 10% of Nb, less than or equal to 0.5% of Nb, and the balance of Fe and unavoidable impurities, and the corrosion-resistant non-magnetic steel is prepared by vacuum melting, bottom casting, die casting and heating rolling, wherein the corrosion-resistant non-magnetic steel is prepared by adding elements such as P, Mo and Nb with lower price to replace expensive Ni elements, so that the manufacturing cost is reduced and the nickel resource is saved, meanwhile, P, Mo and Nb have corrosion resistance consistent with Ni on the non-magnetic steel, wherein P can improve the anti-atmospheric corrosion capability of the chromium non-magnetic steel, Mo can improve the intergranular corrosion resistance capability of the chromium non-magnetic steel, Nb, has fine grain strengthening and high-magnetic steel strengthening and high-temperature strengthening capability, and meets the requirements of the corrosion resistance.)

1. The corrosion-resistant non-magnetic steel is characterized by comprising the following chemical components, by weight, 0.25% ~ 0.35.35% of C, less than or equal to 0.045% of Si, 2.0% ~ 2.5.5% of A1, 22.5% ~ 25% of Mn, less than or equal to 0.04% of P, 0.5% ~ 2.0.0% of Mo, 6.0% ~ 10% of Cr, less than or equal to 0.5% of Nb, and the balance of Fe and inevitable impurities.

2. The corrosion-resistant nonmagnetic steel according to claim 1, wherein the chemical composition of the corrosion-resistant nonmagnetic steel further comprises 0.8% ~ 2.0.0% of Ti.

3. The corrosion-resistant nonmagnetic steel according to claim 2, wherein the chemical composition of the corrosion-resistant nonmagnetic steel comprises, by weight, 0.26% of C ~ 0.31.31%, 0.040% of Si, 2.2% of A1, ~ 2.5.5%, 22.5% of Mn ~ 24.5.5%, 0.04% of P, 0.55% of Mo ~ 2.0.0%, 6.0% of Cr ~ 8.0.0%, 0.45% of Nb, 1.0% of Ti ~ 1.6.6%, and the balance of Fe and inevitable impurities.

4. The corrosion-resistant nonmagnetic steel according to claim 3, wherein the chemical composition of the corrosion-resistant nonmagnetic steel comprises, in weight percent: c: 0.30%, Si: 0.035%, a 1: 2.5%, Mn: 22.5%, P: 0.04%, Mo: 1.8%, Cr: 7.5%, Nb: 0.42%, Ti: 1.4 percent, and the balance of Fe and inevitable impurities.

5. The corrosion-resistant nonmagnetic steel according to claim 1, wherein the yield strength of the corrosion-resistant nonmagnetic steel is 380 to 450 MPa.

6. The corrosion-resistant nonmagnetic steel according to claim 1, wherein the tensile strength of the corrosion-resistant nonmagnetic steel is 620 to 650 MPa.

7. Method for the production of a corrosion resistant nonmagnetic steel according to any of claims 1 to 6, characterized in that it comprises the following steps:

Vacuum smelting: mixing raw materials according to the proportion of each chemical component in the corrosion-resistant non-magnetic steel, and carrying out vacuum melting by using an electric furnace to obtain an ingot;

Bottom pouring die casting: removing an oxide layer on the surface of the ingot after smelting, and melting to form a casting blank;

Heating and rolling, namely rolling the casting blank at the temperature of 1120 ℃ of ~ 1200 ℃ and then cooling the casting blank in air to room temperature to prepare a hot rolled plate.

8. The corrosion-resistant nonmagnetic steel as claimed in claim 7, wherein said step of heating and rolling further comprises a tempering treatment, the temperature of said tempering treatment being 500 ℃ ~ 650 ℃.

9. the corrosion-resistant nonmagnetic steel according to claim 7, wherein in the vacuum melting step, the electric furnace is a vacuum induction melting furnace.

10. the corrosion-resistant nonmagnetic steel according to claim 7, wherein the corrosion-resistant nonmagnetic steel is austenite grains having a grain size of 5 μm ~ 12 μm.

Technical Field

The invention relates to the technical field of steel smelting, in particular to corrosion-resistant non-magnetic steel and a preparation method thereof.

Background

The non-magnetic steel is also called non-magnetic steel and non-magnetic steel, is steel which has no ferromagnetism and can not be magnetized, belongs to austenite of Fe-Mn-Al-C series, has stable structure and excellent mechanical property, and the chemical composition of the non-magnetic steel determines the electromagnetic property. The non-magnetic steel is widely applied to the field of large and medium transformers, electromagnets, precision instruments and other equipment.

However, the non-magnetic steel is easily corroded and worn under the action of factors such as temperature, corrosive medium and mechanics for a long time, and further causes damage to equipment such as transformers and precision instruments. The corrosion resistance of the traditional non-magnetic steel is enhanced by adding alloy elements such as Cr, Ni and Mn, although nickel is an excellent corrosion-resistant material, the manufacturing cost of the non-magnetic steel is high due to the relative shortage and high price of the domestic nickel resources, so that the corrosion-resistant non-magnetic steel with high cost performance and nickel resource saving is urgently needed.

Disclosure of Invention

Therefore, it is necessary to provide a corrosion-resistant non-magnetic steel and a preparation method thereof to solve the problems of easy corrosion and high cost of a corrosion-resistant component nickel.

The chemical components of the corrosion-resistant non-magnetic steel comprise, by weight, 0.25% ~ 0.35.35% of C, less than or equal to 0.045% of Si, 2.0% ~ 2.5.5% of A1, 22.5% ~ 25% of Mn, less than or equal to 0.04% of P, 0.5% ~ 2.0.0% of Mo, 6.0% ~ 10% of Cr, less than or equal to 0.5% of Nb, and the balance of Fe and inevitable impurities.

in one embodiment, the chemical composition of the corrosion-resistant non-magnetic steel further comprises 0.8% ~ 2.0.0% of Ti.

In one embodiment, the chemical components of the corrosion-resistant non-magnetic steel comprise, by weight, 0.26% ~ 0.31.31% of C, less than or equal to 0.040% of Si, 2.2% ~ 2.5.5% of A1, 22.5% ~ 24.5.5% of Mn, less than or equal to 0.04% of P, 0.55% ~ 2.0.0% of Mo, 6.0% ~ 8.0.0% of Cr, less than or equal to 0.45% of Nb, 1.0% ~ 1.6.6% of Ti, and the balance of Fe and inevitable impurities.

In one embodiment, the corrosion-resistant nonmagnetic steel comprises the following chemical components in percentage by weight: c: 0.30%, Si: 0.035%, a 1: 2.5%, Mn: 22.5%, P: 0.04%, Mo: 1.8%, Cr: 7.5%, Nb: 0.42%, Ti: 1.4 percent, and the balance of Fe and inevitable impurities.

In one embodiment, the yield strength of the corrosion-resistant non-magnetic steel is 380MPa to 450 MPa.

In one embodiment, the tensile strength of the corrosion-resistant non-magnetic steel is 620MPa to 650 MPa.

The invention also aims to provide a preparation method of the corrosion-resistant non-magnetic steel.

The purpose is realized by the following technical scheme:

a preparation method of corrosion-resistant nonmagnetic steel comprises the following steps:

Vacuum smelting: mixing raw materials according to the proportion of each chemical component in the corrosion-resistant non-magnetic steel, and carrying out vacuum melting by using an electric furnace to obtain an ingot;

Bottom pouring die casting: removing an oxide layer on the surface of the ingot after smelting, and melting to form a casting blank;

heating and rolling, namely rolling the casting blank at the temperature of 1120 ℃ of ~ 1200 ℃ and then cooling the casting blank in air to room temperature to prepare a hot rolled plate.

In one embodiment, the heating and rolling step further comprises a tempering treatment, and the temperature of the tempering treatment is 500 ℃ ~ 650 ℃.

in one embodiment, in the vacuum melting step, the electric furnace is a vacuum induction melting furnace.

in one embodiment, the corrosion-resistant non-magnetic steel is austenite grains with the grain size of 5 mu m ~ 12 mu m.

According to the corrosion-resistant non-magnetic steel, expensive Ni elements are replaced by adding elements such as P, Mo and Nb with lower price, the manufacturing cost is reduced, nickel resources are saved, P, Mo and Nb have corrosion resistance consistent with that of Ni for the non-magnetic steel, P can improve the atmospheric corrosion resistance of the non-magnetic steel, Mo can improve the intergranular corrosion resistance of chromium-series non-magnetic steel, Nb has fine-grain strengthening and dispersion strengthening effects on the chromium-series non-magnetic steel, the high-temperature oxidation resistance and the corrosion resistance of the non-magnetic steel are improved, and the corrosion-resistant non-magnetic steel meets the requirements of high cost performance and nickel resource saving.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to make the aforementioned objects, features and advantages of the invention more comprehensible. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

The invention provides corrosion-resistant non-magnetic steel, which comprises the following chemical components, by weight, 0.25% ~ 0.35.35% of C, less than or equal to 0.045% of Si, 2.0% ~ 2.5.5% of A1, 22.5% ~ 25% of Mn, less than or equal to 0.04% of P, 0.5% ~ 2.0.0% of Mo, 6.0% ~ 10% of Cr, less than or equal to 0.5% of Nb, and the balance of Fe and inevitable impurities.

Wherein, C (Carbon) has double properties in non-magnetic steel, on one hand, the strength of the corrosion-resistant non-magnetic steel can be ensured, and simultaneously, the corrosion-resistant non-magnetic steel is beneficial to forming and stabilizing austenite structure, on the other hand, because the affinity of Carbon and chromium is very large, the chromium forming carbide with Carbon is more along with the increase of the Carbon content in the corrosion-resistant non-magnetic steel, thereby the corrosion resistance of the corrosion-resistant non-magnetic steel is obviously reduced, in order to ensure that the corrosion-resistant non-magnetic steel has certain strength performance and corrosion resistance performance, the Carbon content is controlled to be 0.25 percent ~ 0.35.35 percent, and is preferably 0.26 percent ~ 0.31.31 percent.

Wherein, Si (Silicon) further plays a role in solid solution strengthening for the corrosion-resistant nonmagnetic steel, can improve the corrosion resistance and the high-temperature oxidation resistance of the corrosion-resistant nonmagnetic steel, and simultaneously, a certain amount of Silicon is added into the corrosion-resistant nonmagnetic steel, so that the resistivity of the corrosion-resistant nonmagnetic steel can be improved, and eddy current is reduced. The present invention controls the silicon content to not more than 0.045%, preferably not more than 0.040%.

The A1 (aluminum) is favorable for solid solution of an austenite structure, prevents carbide from being formed in the corrosion-resistant non-magnetic steel, improves the non-magnetic property of the corrosion-resistant non-magnetic steel, and simultaneously, a proper amount of aluminum is added into the corrosion-resistant non-magnetic steel, formed oxides are dispersed in the steel, thereby preventing the continuous growth of crystal grains when the corrosion-resistant non-magnetic steel is heated, and improving the hardenability and the oxidation resistance of the corrosion-resistant non-magnetic steel, thereby improving the corrosion resistance of the corrosion-resistant non-magnetic steel.

The effect of Mn (Manganese) on the austenite structure is similar to that of Ni, namely the austenite structure of the corrosion-resistant non-magnetic steel can be stabilized, so that the corrosion-resistant non-magnetic steel still has lower relative magnetic conductivity under higher magnetic field intensity, meanwhile, Mn can prevent the continuous growth of crystal grains when the corrosion-resistant non-magnetic steel is heated, and the toughness of the corrosion-resistant non-magnetic steel is not reduced when the corrosion-resistant non-magnetic steel is tempered and brittle, Mn can improve the hardenability of the corrosion-resistant non-magnetic steel, and reduce cracking, twisting, deformation and the like in the production process of the corrosion-resistant non-magnetic steel, and the Mn content is controlled to be 22.5% ~ 25%, preferably 22.5% ~ 24.5.5%.

Among them, P (Phosphorus) is an impurity element in general steel, but the harmfulness of P in austenitic steel is not as remarkable as that in general steel, and Phosphorus has a certain strengthening effect on the corrosion-resistant non-magnetic steel and can improve the anti-atmospheric corrosion effect of the corrosion-resistant non-magnetic steel. The phosphorus content is controlled to be not more than 0.04 percent.

Wherein, Mo (Molybdenum) can solid solution strengthen ferrite, improve the strength and hardness of the corrosion-resistant non-magnetic steel, simultaneously reduce the critical cooling speed of the corrosion-resistant non-magnetic steel, improve the hardenability, heat resistance and high-temperature strength of the corrosion-resistant non-magnetic steel, and improve the corrosion resistance of the corrosion-resistant non-magnetic steel, thereby preventing the corrosion resistance of the corrosion-resistant non-magnetic steel from pitting corrosion in a medium containing chloride ions and an organic acid environment, and the content of the Molybdenum is controlled to be 0.5 percent ~ 2.0.0 percent, preferably 0.55 percent ~ 2.0.0 percent.

Wherein, Cr (Chromium) and Fe form a continuous solid solution, the Cr promotes the surface of the corrosion-resistant non-magnetic steel to form a passive film, the corrosion resistance of the corrosion-resistant non-magnetic steel under a corrosion environment is improved, such as a nitric acid environment, and meanwhile, the Cr can improve the wear resistance and the oxidation resistance of the corrosion-resistant non-magnetic steel, the Cr content is controlled to be 6.0 percent ~ 10 percent, and preferably 6.0 percent ~ 8.0.0 percent.

The invention controls the content of Niobium not more than 0.5 percent, preferably not more than 0.45 percent, in order to further prevent intergranular corrosion, the corrosion-resistant non-magnetic steel is also added with a certain content of Ti (Titanium), the Titanium is a strong deoxidizer of the corrosion-resistant non-magnetic steel, prevents intergranular corrosion, simultaneously can compact the internal structure of the steel, refine grains, reduce aging sensitivity and cold brittleness and improve welding performance, and the content of Titanium in the invention is controlled to be 0.8 percent ~ 2.0.0 percent, preferably 1.0 percent ~ 1.6.6 percent.

The corrosion-resistant non-magnetic steel is austenite crystal grains with the grain size of 5 mu m ~ 12 mu m, expensive Ni elements are replaced by elements such as P, Mo and Nb with lower price, the manufacturing cost is reduced, the nickel resources are saved, meanwhile, P, Mo and Nb have corrosion resistance consistent with that of Ni for the non-magnetic steel, P can improve the atmospheric corrosion resistance of the non-magnetic steel, Mo can improve the intergranular corrosion resistance of chromium-series non-magnetic steel, Nb has the fine grain strengthening and dispersion strengthening effects on the chromium-series non-magnetic steel, the high-temperature oxidation resistance and the corrosion resistance of the non-magnetic steel are improved, and the corrosion-resistant non-magnetic steel meets the requirements of high cost performance and nickel resource saving.

A method for manufacturing a corrosion-resistant nonmagnetic steel according to an embodiment is one of the above corrosion-resistant nonmagnetic steels, and includes the steps of:

Vacuum smelting: mixing the raw materials according to the proportion of each chemical component in the corrosion-resistant non-magnetic steel, and carrying out vacuum melting by using an electric furnace to obtain an ingot. Specifically, the electric furnace is a vacuum induction melting furnace, the iron raw material is melted into molten iron in a melting chamber of the vacuum induction melting furnace, and the molten iron is more than 80m³Introducing inert gas argon into the smelting chamber at flow strength of/h until the pressure in the chamber reaches 0.50Pa ~ 0.70.70 Pa to approach vacuum, removing rust and oil on the surfaces of other raw materials, then sequentially entering the smelting chamber from high to low according to melting points, and obtaining an ingot after melting and refining, wherein the smelting is carried out in a vacuum environment to avoid defects caused by ingot oxidation, such as air holes, slag holes, oxide slag inclusion, black points, pocking marks and the like, and removing impurity elements with steam pressure higher than that of each raw material at the smelting temperature through volatilization, and meanwhile, a certain deoxidizer is added into the smelting chamber to adjust the oxidability of molten steel and further avoid ingot oxidation.

Bottom pouring die casting: and removing an oxide layer on the surface of the ingot after smelting, and melting to form a casting blank. Specifically, the particles of the clamped objects in the molten steel are large and easy to float upwards, the deoxidizer or the impurity particles are oxidized by a small amount of oxygen in the electric furnace to form an oxide layer attached to the surface of the cast ingot, the oxide layer on the surface is removed by a slag scraper before the cast ingot is solidified, and the cast ingot is cast and cooled after being melted by the electric furnace at high temperature to obtain the cast ingot.

The method comprises the following steps of heating and rolling, wherein a casting blank is rolled at the temperature of 1120 ℃ ~ 1200 ℃ and then is cooled in air to room temperature to prepare a hot rolled plate, specifically, the casting blank is subjected to high-temperature heat preservation for 2 ~ 3 hours and then is rolled by a hot rolling mill, the initial rolling temperature is controlled at 1000 ℃ ~ 1120 ℃, the final rolling temperature is controlled at 800 ℃ ~ 950 ℃, the casting blank is subjected to hot rolling and then is tempered for 40 ~ 80 minutes and then is cooled in air to room temperature, the tempering temperature is controlled at 500 ℃ ~ 650 ℃, the deformation and the cracking of the hot rolled plate are easily caused due to the existence of large internal stress of quenched steel, the brittleness of the hot rolled plate can be reduced through the tempering treatment, the internal stress of the hot rolled plate can be eliminated or reduced, and the stability of the hot rolled plate in.

The preparation method of the corrosion-resistant non-magnetic steel has the advantages of simple operation process, easily obtained raw materials and low cost, and is suitable for industrial production.

the following are specific examples: