阅读说明：本技术 一种铁铬铝合金棒材及其制备方法 (Iron-chromium-aluminum alloy bar and preparation method thereof ) 是由 刘志坚 丘源 陈远星 何坤宏 于 2019-12-12 设计创作，主要内容包括：本发明提供的一种铁铬铝合金棒材及其制备方法,所述铁铬铝合金棒材的制备方法采用真空感应熔炼炉冶炼,原材料熔化后,提升合金熔液温度至1550～1580℃后精炼；精炼末期调整合金熔液温度在1530～1550℃后,浇注成电渣重熔用的电极棒；将电极棒的表面抺涂铝粉混合液并烘烤,经电渣重熔冶炼,熔出的整支合金电渣锭中铝含量均匀；合金电渣锭经表面精整、加热锻造和热轧成直条,再将直条剥皮磨光,制得光亮铁铬铝合金棒料,最后将所述光亮铁铬铝合金棒料经氧化焙烧处理,制备出表面形成一层致密、粗糙的耐高温、耐磨氧化层的铁铬铝合金棒材,解决了铁铬铝合金棒材氧化层易脱落、不耐磨、绝缘性差的难题。(The invention provides an iron-chromium-aluminum alloy bar and a preparation method thereof, the preparation method of the iron-chromium-aluminum alloy bar adopts a vacuum induction smelting furnace to smelt, and after raw materials are melted, the temperature of alloy melt is raised to 1550-1580 ℃ and then the alloy melt is refined; adjusting the temperature of the alloy melt at 1530-1550 ℃ in the last refining stage, and then pouring into an electrode bar for electroslag remelting; coating and baking aluminum powder mixed liquid on the surface of the electrode rod, and carrying out electroslag remelting smelting to obtain a whole alloy electroslag ingot with uniform aluminum content; the alloy electroslag ingot is subjected to surface finishing, heating forging and hot rolling to form a straight strip, the straight strip is peeled and polished to prepare a bright iron-chromium-aluminum alloy bar, and finally the bright iron-chromium-aluminum alloy bar is subjected to oxidation roasting treatment to prepare the iron-chromium-aluminum alloy bar with a compact and rough high-temperature-resistant and wear-resistant oxide layer formed on the surface.)

1. The iron-chromium-aluminum alloy bar is characterized in that an oxide layer is formed on the surface of the iron-chromium-aluminum alloy bar, and the iron-chromium-aluminum alloy bar comprises the following alloy components in percentage by mass, wherein the carbon content is less than or equal to 0.03%, and the chromium content is as follows: 19.5-22%, aluminum: 3-5%, less than or equal to 0.70% of titanium, less than or equal to 0.60% of zirconium, less than or equal to 0.25% of tungsten, less than or equal to 0.30% of molybdenum, less than or equal to 0.25% of vanadium, less than or equal to 0.30% of niobium, and the balance of iron.

2. The preparation method of the iron-chromium-aluminum alloy bar is characterized by comprising the following steps:

s1: the alloy of claim 1, wherein the composition of C is 0.03% or less, Cr is: 19.5-22%, aluminum: 3-5%, less than or equal to 0.70% of titanium, less than or equal to 0.60% of zirconium, less than or equal to 0.25% of tungsten, less than or equal to 0.30% of molybdenum, less than or equal to 0.25% of vanadium, less than or equal to 0.30% of niobium, and the balance of iron, and preparing raw materials according to mass percentage;

s2: smelting by adopting a vacuum induction smelting furnace, putting the raw materials of iron, chromium, carbon, tungsten, molybdenum, vanadium and niobium prepared in the step S1 into a crucible of the vacuum smelting furnace, heating to completely melt the raw materials in the crucible, adding the raw materials of aluminum, titanium and zirconium prepared in the step S1 to smelt, raising the temperature to 1550-1580 ℃, and refining for 25-50 minutes to obtain alloy melt;

s3: adjusting the alloy melt to a pouring temperature at the last stage of refining, and pouring the alloy melt into an electrode bar for electroslag remelting, wherein the pouring temperature is controlled to 1530-1550 ℃;

s4: coating and baking aluminum powder mixed liquid on the surface of the electrode rod, and remelting the electroslag to obtain an alloy electroslag ingot;

s5: after surface finishing, the alloy electroslag ingot is heated, forged and hot-rolled into a straight strip;

s6: peeling and polishing the straight strip to obtain a bright alloy bar;

s7: and carrying out oxidizing roasting treatment on the bright alloy bar to prepare the iron-chromium-aluminum alloy bar.

3. The preparation method of the iron-chromium-aluminum alloy bar according to claim 2, wherein in step S4, the step of coating the aluminum powder mixed solution and baking comprises the steps of:

s41: removing oxide skin on the surface of the electrode rod;

s42: preparing the aluminum powder mixed solution, and uniformly coating the aluminum powder mixed solution on the electrode rod with the scale removed;

s43: and naturally drying the aluminum powder mixed liquid coated on the electrode rod, and baking the electrode rod at the temperature of 100-250 ℃ for 1-3 hours.

4. The preparation method of the iron-chromium-aluminum alloy bar according to claim 2 or 3, wherein the aluminum powder mixed solution is prepared by mixing 0.2-0.4% by mass of industrial aluminum powder and water glass of the electrode bar according to the mass ratio of 1: 10-20, and uniformly mixing and stirring.

5. The method of claim 4, wherein in step S42, the aluminum powder mixture is applied to 1/4-2/5 of the total length of the electrode rod from the end of the electrode rod where electroslag remelting starts.

6. The method for preparing the iron-chromium-aluminum alloy bar according to claim 2, wherein in step S4, argon gas is continuously introduced into the electroslag remelting process, and meanwhile, aluminum particles with the weight percentage of 0.1-0.3% of the electrode bar are added into the electroslag remelting process until the electroslag remelting is finished, so as to prepare the alloy electroslag ingot with uniform aluminum content.

7. The method of claim 6, wherein the aluminum particles are added in two stages during the electroslag remelting process:

the first stage is as follows: adding 25-35% of the aluminum particles in the total mass when the electroslag remelting is normal;

and a second stage: and uniformly adding the rest aluminum particles until the electroslag remelting is finished.

8. The method of claim 2, wherein in step S4, the electroslag remelting utilizes Al as a slag system and mass ratio₂O₃：CaF₂：TiO₂7: 3: 1, the total mass of the slag system is 4-6% of the mass percentage of the electrode rod.

9. The method of claim 2, wherein the hot forging and hot rolling in step S5 includes the steps of:

s51: the forging process comprises the following steps: after the surface of the alloy electroslag ingot is finished, charging and heating to 1150-1200 ℃, and keeping the temperature for 60 minutes; the final forging temperature is more than 850 ℃; forging to form a forging stock, and slowly cooling the forging stock to normal temperature;

s52: the hot rolling process comprises the following steps: after finishing the surface of the forging stock, charging into a furnace and heating to 1100-1150 ℃, wherein the heat preservation time is 50 minutes; the finishing temperature is more than 830 ℃; and after the straight strip is formed by hot rolling, the straight strip is subjected to stack cooling or slow cooling to the normal temperature.

10. The method for preparing the iron-chromium-aluminum alloy bar material as claimed in claim 2, wherein in step S7, the oxidizing roasting treatment is carried out by placing the bright alloy bar material in an atmosphere furnace into which oxygen with a purity of not less than 70% is introduced, wherein the roasting temperature is 1150-1200 ℃, the temperature is kept for 1.5-2 hours, and finally the bright alloy bar material is cooled to normal temperature along with the furnace.

Technical Field

The invention relates to the field of alloy preparation, in particular to an iron-chromium-aluminum alloy bar and a preparation method thereof.

Background

With the technical progress of the automobile and ceramic industries, a large amount of high-temperature resistant alloy materials are required to be used. When in use, the alloy material is required to have stable quality and good consistency at high temperature, and also provides higher requirements for the surface quality of the alloy material. At present, the mode of coating a high-temperature-resistant layer on the surface of high-temperature alloy or metal can meet the requirements. However, the high-temperature alloy has the defects of high price, low surface wear resistance at high temperature and poor insulation. The metal surface coating is very easy to crack and peel at high temperature due to the intrinsic brittleness of the coating material, so that the coating fails, and in severe cases, equipment is damaged and shutdown is caused.

The iron-chromium-aluminum alloy has good oxidation resistance and low price. In the prior art, the main defects of the iron-chromium-aluminum alloy are low high-temperature strength, poor plasticity and toughness and easy brittleness, and after high-temperature use, large crystal grains cause increased brittleness and short service life; meanwhile, if trace rare earth elements are added into the alloy, a smooth oxide film layer is formed on the surface of the alloy, and the alloy is not wear-resistant; if the rare earth element is added too much, cracks can occur during hot working, and even the whole material is scrapped.

The aluminum content in the iron-chromium-aluminum alloy component has a large influence on the material performance, and the following problems can occur in the electroslag remelting process in the material preparation process: the aluminum burning loss is more at the beginning of electroslag remelting, the aluminum content is lower than that at the middle and later stages of electroslag remelting, and the components of alloy materials have deviation, so that the consistency of the alloy properties is poor. In addition, when the iron-chromium-aluminum alloy is roasted in the atmospheric atmosphere, the thickness of an oxide film layer on the surface of the alloy is thin, the surface is smooth, the wear resistance and the insulativity of the alloy are poor, and the production continuity and the product stability are influenced during use.

Disclosure of Invention

In view of the above situation, the invention provides an iron-chromium-aluminum alloy bar and a preparation method thereof, the prepared iron-chromium-aluminum alloy bar can form a compact and rough high-temperature-resistant and wear-resistant oxide layer on the surface, and the problems of easy falling-off of the oxide layer, poor wear resistance and poor insulativity of the iron-chromium-aluminum alloy bar are solved.

In order to achieve the purpose, the invention provides an iron-chromium-aluminum alloy bar, wherein an oxide layer is formed on the surface of the iron-chromium-aluminum alloy bar, and the alloy components of the iron-chromium-aluminum alloy bar are that carbon (C) is less than or equal to 0.03 percent and chromium (Cr): 19.5-22%, aluminum (Al): 3-5%, titanium (Ti) is less than or equal to 0.70%, zirconium (Zr) is less than or equal to 0.60%, tungsten (W) is less than or equal to 0.25%, molybdenum (Mo) is less than or equal to 0.30%, vanadium (V) is less than or equal to 0.25%, niobium (Nb) is less than or equal to 0.30%, and the balance is iron (Fe).

The invention also provides a preparation method of the iron-chromium-aluminum alloy bar, which comprises the following steps:

s1: the alloy of claim 1, wherein the composition of C is 0.03% or less, Cr is: 19.5-22%, aluminum: 3-5%, less than or equal to 0.70% of titanium, less than or equal to 0.60% of zirconium, less than or equal to 0.25% of tungsten, less than or equal to 0.30% of molybdenum, less than or equal to 0.25% of vanadium, less than or equal to 0.30% of niobium, and the balance of iron, and preparing raw materials according to mass percentage;

s2: smelting by adopting a vacuum induction smelting furnace, putting the raw materials of iron, chromium, carbon, tungsten, molybdenum, vanadium and niobium prepared in the step S1 into a crucible of the vacuum smelting furnace, heating to completely melt the raw materials in the crucible, adding the raw materials of aluminum, titanium and zirconium prepared in the step S1 to smelt, raising the temperature to 1550-1580 ℃, and refining for 25-50 minutes to obtain alloy melt;

s3: adjusting the alloy melt to a pouring temperature at the last stage of refining, and pouring the alloy melt into an electrode bar for electroslag remelting, wherein the pouring temperature is controlled to 1530-1550 ℃;

s4: coating and baking aluminum powder mixed liquid on the surface of the electrode rod, and remelting the electroslag to obtain an alloy electroslag ingot;

s5: after surface finishing, the alloy electroslag ingot is heated, forged and hot-rolled into a straight strip;

s6: peeling and polishing the straight strip to obtain a bright alloy bar;

s7: and carrying out oxidizing roasting treatment on the bright alloy bar to prepare the iron-chromium-aluminum alloy bar.

Preferably, in step S4, the step of coating and baking the aluminum powder mixed solution includes:

s41: removing oxide skin on the surface of the electrode rod;

s42: preparing the aluminum powder mixed solution, and uniformly coating the aluminum powder mixed solution on the electrode rod with the scale removed;

s43: and naturally drying the aluminum powder mixed liquid coated on the electrode rod, and baking the electrode rod at the temperature of 100-250 ℃ for 1-3 hours.

Preferably, the aluminum powder mixed solution is 0.2-0.4% of industrial aluminum powder and water glass (Na) by mass percentage of the electrode rod₂SiO₃·9H₂O) according to mass 1: 10-20, and uniformly mixing and stirring.

Further, in step S42, the aluminum powder mixture is applied to 1/4-2/5 of the total length of the electrode rod from the end of the electrode rod where electroslag remelting starts.

Preferably, in step S4, argon gas is continuously introduced into the electroslag remelting process, and meanwhile, aluminum particles with a mass percentage of 0.1 to 0.3% of the electrode rod are added into the electroslag remelting process until the electroslag remelting is finished, so as to prepare the alloy electroslag ingot with uniform aluminum content.

Further, in the electroslag remelting process, the aluminum particles are added in two stages: the first stage is as follows: adding 25-35% of the aluminum particles in the total mass when the electroslag remelting is normal; and a second stage: and uniformly adding the rest aluminum particles until the electroslag remelting is finished.

Preferably, in step S4, the slag system and the mass ratio used in the electroslag remelting process are Al₂O₃：CaF₂：TiO₂7: 3: 1, the total mass of the slag system is 4-6% of the mass percentage of the electrode rod.

Preferably, in step S5, the heating forging and hot rolling includes the steps of:

s51: the forging process comprises the following steps: after the surface of the alloy electroslag ingot is finished, charging and heating to 1150-1200 ℃, and keeping the temperature for 60 minutes; the final forging temperature is more than 850 ℃; forging to form a forging stock, and slowly cooling the forging stock to normal temperature;

s52: the hot rolling process comprises the following steps: after finishing the surface of the forging stock, charging into a furnace and heating to 1100-1150 ℃, wherein the heat preservation time is 50 minutes; the finishing temperature is more than 830 ℃; and after the straight strip is formed by hot rolling, the straight strip is subjected to stack cooling or slow cooling to the normal temperature.

Preferably, in step S7, the oxidizing roasting treatment is to place the bright alloy bar in an atmosphere furnace with oxygen having a purity of not less than 70% to perform oxidizing roasting, the roasting temperature is 1150-1200 ℃, the temperature is kept for 1.5-2 hours, and finally the bright alloy bar is cooled to the normal temperature along with the furnace.

The invention has the beneficial effects that:

the invention provides an iron-chromium-aluminum alloy bar and a preparation method thereof, and the method for preparing the iron-chromium-aluminum alloy bar comprises the following steps: smelting by using a vacuum induction smelting furnace, adding aluminum, titanium and zirconium raw materials after the iron, chromium, carbon, tungsten, molybdenum, vanadium and niobium raw materials are completely melted, raising the temperature of alloy melt to 1550-1580 ℃, and then refining; adjusting the temperature of the alloy melt at 1530-1550 ℃ in the last refining stage, and then pouring into an electrode bar for electroslag remelting; then coating and baking the surface of the electrode rod with aluminum powder mixed liquid, remelting the electroslag to obtain an alloy electroslag ingot, and then performing surface finishing, heating forging and hot rolling to form a straight strip; the method comprises the steps of peeling and polishing a straight bar to obtain a bright alloy bar, and finally carrying out oxidizing roasting treatment on the bright alloy bar to obtain the iron-chromium-aluminum alloy bar with a compact and rough high-temperature-resistant and wear-resistant oxide layer formed on the surface. It has the following advantages:

(1) by adding alloy components such as zirconium, titanium, vanadium, niobium, tungsten, molybdenum and the like into the alloy material, the prepared iron-chromium-aluminum alloy bar can obtain better high-temperature resistance and wear resistance, and the alloy material can be reducedBrittleness of gold bars. Among the components of the alloy, the zirconium element plays the roles of deoxidation, purification and grain refinement, so that the oxide film on the surface of the alloy contains Zr with ceramic characteristics₂The O film is beneficial to enhancing the toughness of the oxide film; ti element promotes the formation of Zr₂O film to slow down Al₂O₃Forming; the vanadium element has strong effect of refining grains, and can improve the strength and toughness of the alloy; the niobium element has the function of refining grains, and when the niobium element is heated to 1100-1200 ℃, the grains can still be prevented from growing; the molybdenum element is beneficial to improving the toughness and the wear resistance of the alloy and improving the heat strength of the alloy; the tungsten element has the function of refining grains, so that the wear resistance and the heat strength of the alloy are improved; particularly, rare earth elements are not added in the invention, because trace rare earth elements are added in the iron-chromium-aluminum alloy bar and the preparation method thereof, although the iron-chromium-aluminum alloy bar is beneficial to hot working, the alloy has the condition of smooth oxide film and poor wear resistance during the subsequent oxidation roasting treatment; if the rare earth element is added too much, cracks and even the whole material is scrapped during hot working.

(2) By adopting a vacuum smelting process, the easily burnt alloy elements such as aluminum, titanium, zirconium and the like can be effectively controlled; after the raw materials of iron, chromium, carbon, tungsten, molybdenum, vanadium and niobium are completely melted, the raw materials of aluminum, titanium and zirconium are added, and the operations of temperature raising and refining and the like are carried out, so that the iron-chromium-aluminum alloy has uniform components and less segregation.

(3) The method comprises the steps of coating an aluminum powder mixed solution on an alloy electrode bar and adding aluminum particles in the electroslag remelting process, so that the aluminum element in the alloy is effectively prevented from being consumed by oxidation, the aluminum content in the obtained whole alloy electroslag ingot is uniform, and the problems that the aluminum content of the front end part of the electroslag in the alloy electroslag ingot is low, the aluminum content difference with the aluminum content of the rear end of the electroslag is large, the material composition deviation is large, and the material performance is inconsistent are solved.

(4) In the electroslag remelting process, oxygen is discharged and blocked in a mode of continuously introducing argon, so that elements easy to burn and damage in the iron-chromium-aluminum alloy are effectively controlled.

(5) The oxidation roasting treatment mode for increasing the oxygen concentration is adopted, the surface of the prepared iron-chromium-aluminum alloy bar has a compact and rough high-temperature-resistant and wear-resistant oxide layer with moderate thickness, the condition that a smooth thin oxide layer is generated when the iron-chromium-aluminum alloy bar is subjected to heat treatment in the atmospheric atmosphere is avoided, and the problems that the oxide layer of the iron-chromium-aluminum alloy bar is easy to fall off, is not wear-resistant and has poor insulativity are solved.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples.