TWI507546B - Austenitic alloy and fabricating method thereof - Google Patents

Description

Vostian iron alloy and its manufacturing method

The present invention relates to an iron-based alloy and a method of producing the same, and more particularly to a Worthfield iron-based alloy and a method of producing the same.

Common Worthfield iron alloys include nickel-based superalloys such as Alloy 800H (Alloy 800H), Alloy A-286 (Alloy A-286), Alloy 825 (Alloy 825) and 300 Series stainless steel (such as 310 stainless steel or 321 stainless steel). )Wait. Since the nickel-based superalloy contains a relatively large amount of nickel, the crystal structure of the nickel-based superalloy is mainly the center center cubic (FCC) of the austenitic structure, which is suitable for high temperature machinery. In the case of nature, such as engine components, turbine engine fasteners, high temperature bearings, furnace covers and other workpieces. Generally, good anti-potential properties are required under stress to prolong the service life of the workpiece, so titanium is often added. For example, alloy 800H generally contains 0.15wt% to 0.6wt% of titanium, which can form a precipitation phase with favorable anti-potential properties at high temperature, such as titanium carbide, titanium nitride and nickel nitride (Ni ₃ Ti). The titanium nitride precipitated phase having a higher nitrogen content is produced in the smelting stage, and the average particle diameter is between 3.0 micrometers and 30 micrometers; and the titanium carbide precipitated phase is precipitated during hot working/heat treatment or high temperature application. The average particle size is from about 0.2 microns to about 3.0 microns. Among them, the precipitation of titanium carbide contributes a lot to the anti-potential properties.

The above nickel-based superalloy may be produced by a fuel furnace melting method, an Electric Arc Furnace (EAF) melting method or a vacuum induction melting (VIM) method or a vacuum arc melting (VAM). Method or the like to obtain a nickel-based superalloy mold ingot or continuous casting billet, and then selectively perform subsequent Argon Oxygen Decarburization (AOD) method, vacuum oxygen decarburization (Vacuum Oxygen Decarburization) , VOD) method, electroslag remelting (ESR) method, vacuum arc remelting (VAR) method and other refining processes. Generally, an alloy containing more than 0.6% by weight of titanium element is usually smelted by a vacuum process such as vacuum induction melting or vacuum arc remelting to prevent oxidation and nitridation during atmospheric melting, so that the titanium content in the alloy is greatly reduced. It can also avoid defects or casting failure of the nickel-based superalloy caused by secondary formation of oxide or excessive nitride in the non-vacuum process. However, the vacuum process equipment is not easy to obtain, and the melting cost is high. Moreover, since the nickel-based superalloy product containing a high titanium content is not easily smelted, the ratio of titanium to carbon is not regulated. The ratio of titanium to carbon in a nickel-based superalloy product containing a high titanium content is generally 4 or more and less than 6.

In view of the above, it is urgent to propose a Worthfield iron-based alloy and a method for producing the same, and a non-vacuum melting method or a vacuum melting method can be used to obtain a Worthfield iron-based alloy having high anti-potential properties.

Accordingly, it is an object of the present invention to provide a Worthfield iron-based alloy having high anti-potential properties.

Another object of the present invention is to provide a method for producing a Worthfield iron-based alloy which can be obtained by using a non-vacuum melting method or a vacuum melting method to obtain a Worthfield iron-based alloy having high anti-potential properties.

According to the above object of the present invention, there is provided a Worthfield iron-based alloy comprising 5 wt% to 75 wt% of iron, 7 wt% to 75 wt% of nickel, 15 wt% to 25 wt% of chromium, 0.065 wt% to 0.15 wt% of carbon From 0.5 wt% to 1.35 wt% of titanium, wherein the weight ratio of titanium to carbon is from 6 to 8.5, and the unavoidable impurities are greater than zero and less than or equal to 2 wt%.

According to an embodiment of the present invention, the Worthfield iron-based alloy has a nickel content of 31% by weight to 32% by weight, a chromium content of 21% by weight of chromium, a carbon content of 0.075% by weight to 0.081% by weight, and a titanium content of 0.59 wt% to 0.61 wt%, wherein the weight ratio of titanium to carbon is 7.5 to 7.8, and the balance is iron and unavoidable impurities, wherein the impurities comprise 0.3 wt% to 0.4 wt% of copper, 0.23 wt% to 0.25 wt% Thereafter, 0.7 wt% of manganese, 0.004 wt% of sulfur, and 0.21 wt% to 0.24 wt% of aluminum.

According to an embodiment of the present invention, the Worthite iron-based alloy precipitates a titanium carbide precipitate having a mean particle diameter of more than 0 and less than 30 nm or a precipitate of nitrogen-containing titanium carbide when used at 500 to 950 degrees Celsius.

According to another object of the present invention, a method of manufacturing a Worthfield iron-based alloy is proposed. In the manufacturing method of the Worth iron-based alloy of one embodiment, the following steps are included. Providing a raw material comprising 5 wt% to 75 wt% of iron, 7 wt% to 75 wt% of nickel, 15 wt% to 25 wt% of chromium, 0.065 wt% to 0.15 wt% of carbon, 0.5 wt% to 1.35 wt% of titanium, wherein Titanium to carbon weight ratio of 6 to 8.5, and greater than zero and less than or equal to 2 wt% is unavoidable Free of impurities. The raw material is subjected to a smelting process to form a Worthfield iron-based alloy.

According to an embodiment of the present invention, the above raw material comprises 31% by weight to 32% by weight of nickel, 21% by weight of chromium, 0.075% by weight to 0.081% by weight of carbon, and 0.59% by weight to 0.61% by weight of titanium, wherein titanium and carbon are used. The weight ratio is 7.5 to 7.8, and the balance is iron and unavoidable impurities, wherein the impurities comprise 0.3 wt% to 0.4 wt% copper, 0.23 wt% to 0.25 wt% niobium, 0.7 wt% manganese, 0.004 wt% Sulfur and 0.21% to 0.24% by weight of aluminum.

According to an embodiment of the invention, the smelting process comprises a vacuum induction melting process and a vacuum oxygen decarburization process.

According to an embodiment of the invention, the smelting process comprises using a non-vacuum electric furnace smelting method and an electroslag remelting method.

According to an embodiment of the invention, the electroslag remelting method further comprises performing a non-vacuum electric furnace smelting method to melt the raw material to form a Worthfield iron-based alloy embryo. The electroslag remelting method is performed to form the Worthite iron alloy embryo into a Worthfield iron alloy, wherein the electroslag remelting method further comprises adding the Worthfield iron alloy embryo and the refining slag to the electroslag remelting furnace. And the refining slag contains 3 wt% to 20 wt% of titanium dioxide.

According to an embodiment of the invention, the composition of the refining slag further comprises carbon difluoride, calcium oxide, magnesium oxide, aluminum oxide, and cerium oxide.

According to an embodiment of the present invention, the Worthite iron-based alloy precipitates a titanium carbide precipitate having a mean particle diameter of more than 0 and less than 30 nm or a precipitate of nitrogen-containing titanium carbide when used at 500 to 950 degrees Celsius.

In the present invention, since the Vostian iron-based alloy utilizes a higher weight ratio of titanium to carbon, the Worthite iron-based alloy is subjected to high temperature application. A titanium carbide precipitate having an average particle diameter of more than 0 and less than 30 nm or a precipitate of nitrogen-containing titanium carbide is produced, thereby increasing the anti-potential denaturation of the Worthfield iron-based alloy. In addition, the manufacturing method of the Worthite iron alloy can be obtained by vacuum induction melting method and vacuum smelting method of vacuum oxygen decarburization method, in order to avoid reduction of titanium component in the Worth iron alloy. The non-vacuum electric furnace melting method and the electroslag remelting method are used in the non-vacuum smelting method, and the refining slag containing titanium dioxide is used in the electroslag remelting furnace process to prevent a large loss of the titanium component during refining.

100‧‧‧ method

110, 120‧‧‧ steps

The above and other objects, features, advantages and embodiments of the present invention will become more <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; A flow chart of the manufacturing method.

Fig. 2A is a graph showing test results of anti-latent denaturation of the Worthite iron-based alloys of Examples 1 and 2 and Comparative Examples under the first test conditions.

Fig. 2B is a graph showing the test results of the anti-potential denaturation of the Vostian iron-based alloys of Examples 1 and 2 and Comparative Examples under the second test conditions.

Fig. 3 is a photograph of a high-resolution transmission electron microscope of the Vostian iron-based alloy of Example 2 of the present invention after the creep test of the first test condition.

The technical content, structural features, achieved goals and effects of the present invention will be described in detail below with reference to embodiments of the present invention.

In an embodiment of the invention, the Vostian iron alloy comprises 5 wt% to 75 wt% iron, 7 wt% to 75 wt% nickel, 15 wt% to 25 wt% chromium, 0.065 wt% to 0.15 wt% carbon, 0.5 wt% to 1.35 wt% titanium, and greater than zero and less than or equal to 2 wt% of unavoidable impurities, wherein the weight ratio of titanium to carbon is 6 to 8.5. In an exemplary embodiment, the Vostian iron-based alloy comprises 31 wt% to 32 wt% nickel, 21 wt% chromium, 0.075 wt% to 0.081 wt% carbon, 0.59 wt% to 0.61 wt% titanium, wherein titanium and carbon The weight ratio is 7.5 to 7.8, and the balance is iron and unavoidable impurities, wherein the impurities comprise 0.3 wt% to 0.4 wt% copper, 0.23 wt% to 0.25 wt% niobium, 0.7 wt% manganese, 0.004 wt%. Sulfur and 0.21% to 0.24% by weight of aluminum.

In one example, the Vostian iron-based alloy includes titanium carbide precipitates having an average particle diameter of more than 0 and less than 30 nanometers or titanium carbide precipitates containing nitrogen (titanium carbide precipitates and nitrogen-containing titanium carbides may also be collectively referred to as Is Ti(C,N)). In an exemplary example, when the Worthfield iron alloy is applied in a high temperature environment, the crystal phase composition of the Worthfield iron alloy will produce titanium carbide precipitates or inclusions having an average particle diameter of more than 0 and less than 30 nm. Nitrogen-based titanium carbide precipitates, these nano-scale titanium carbide precipitates or nitrogen-containing titanium carbide precipitates can block the dislocation slip in the Worthian iron-based alloy, causing the slip of the difference row to produce a partial bend The phenomenon of folding further increases the anti-potential denaturation of the Worth Iron alloy. The above high temperature environment may be from 500 degrees Celsius to 950 degrees Celsius.

Please refer to FIG. 1. FIG. 1 is a flow chart showing a method 100 for manufacturing a Worthfield iron-based alloy according to an embodiment of the present invention. In method 100, step 110 provides a feedstock. The raw material comprises 5 wt% to 75 wt% iron, 7 wt% to 75 wt% nickel, 15 wt% to 25 wt% chromium, 0.065 wt% To 0.15 wt% carbon, 0.5 wt% to 1.35 wt% titanium, and more than zero and less than or equal to 2 wt% of unavoidable impurities, wherein the weight ratio of titanium to carbon is 6 to 8.5. In an exemplary embodiment, the feedstock comprises 31 wt% to 32 wt% nickel, 21 wt% chromium, 0.075 wt% to 0.081 wt% carbon, 0.59 wt% to 0.61 wt% titanium, wherein the weight ratio of titanium to carbon is 7.5. To 7.8, and the balance being iron and unavoidable impurities, wherein the impurities comprise 0.3 wt% to 0.4 wt% copper, 0.23 wt% to 0.25 wt% niobium, 0.7 wt% manganese, 0.004 wt% sulfur, and 0.21 wt%. % to 0.24% by weight of aluminum.

In step 120, the foregoing raw materials are subjected to a melting process to form a Worthfield iron-based alloy. In one example, the smelting process may be a vacuum melting process or a non-vacuum smelting process to produce a Worthfield iron-based alloy. For example, in the case where the vacuum equipment is sufficient, a vacuum apparatus is used to perform a vacuum induction melting method to form a Worthite iron-based alloy embryo, and then a vacuum oxygen decarburization method is used to refine the Vostian iron-based alloy embryo. To form a Worthfield iron alloy. In another example, a non-vacuum device can also be used for the smelting process, such as using a non-vacuum electric furnace smelting method to form a Worthite iron alloy embryo, and then using an electroslag remelting method to refine Worthfield. Iron-based alloy embryos to form a Worth Iron alloy. In the electroslag remelting method, the refining slag is first added to the electroslag remelting furnace, and when the current supplied by the electroslag remelting furnace passes through the slag, heat is generated, thereby melting the Worth iron system which is subsequently added to the electroslag remelting furnace. The alloy embryo can be used as a heat source to melt the Worthfield iron-based alloy embryo to achieve the effect of secondary refining. Among them, when a Worstian iron-based alloy is produced by a non-vacuum method, the titanium component reacts with the atmosphere to oxidize and nitrite, resulting in a decrease in the titanium component of the Worthfield iron-based alloy. Therefore, it can be added in the electroslag remelting method. The refining slag containing 3 wt% to 20 wt% of titanium dioxide is introduced into the electroslag remelting furnace to supplement the lost titanium component. In an exemplary embodiment, the components of the refining slag used may further comprise carbon difluoride, calcium oxide, magnesium oxide, aluminum oxide, and cerium oxide. In addition, in the electroslag remelting method, it is possible to protect with an inert gas such as helium to avoid excessive loss of the titanium component.

In one example, the Worth iron alloy obtained by the method of manufacturing the Worth iron alloy according to the embodiment of the present invention may be subjected to a forging or rolling step to form a desired appearance. The surface condition of the Stone alloy is then subjected to surface treatment steps such as cutting, grinding or peeling to ensure the surface quality of the Worthfield iron alloy. In an exemplary example, the Worthfield iron alloy can be subjected to hot working or cold working methods such as forging, rolling, drawing, and pipe-making to form sheets, coils, rods, wires or pipes, etc. Used in various industrial types.

Several embodiments and a comparative example are exemplified below to demonstrate that the Worthfield iron-based alloy obtained by the method for producing the Worth iron-based alloy according to the embodiment of the present invention not only has a high weight ratio of titanium to carbon, And has high resistance to potential changes.

In Example 1, the raw material was first provided. The raw material comprises 32% by weight of nickel, 21% by weight of chromium, 0.081% by weight of carbon, 0.61% by weight of titanium, and the balance of iron and unavoidable impurities, wherein the weight ratio of titanium to carbon is about 7.5, and the impurity contains 0.3. Bt% copper, 0.23 wt% bismuth, 0.7 wt% manganese, 0.004 wt% sulfur, and 0.24 wt% aluminum. After the raw material is supplied, a vacuum induction melting method is used to form a Worthite iron-based alloy embryo, and then a vacuum oxygen decarburization method is used to refine the Worthfield iron-based alloy embryo to form an implementation. Example 1 of the Worth Iron Alloy.

In Example 2, a raw material was first provided. The raw material comprises 31% by weight of nickel, 21% by weight of chromium, 0.075% by weight of carbon, 0.59% by weight of titanium, and the balance of iron and unavoidable impurities, wherein the weight ratio of titanium to carbon is about 7.8, and the impurity contains 0.4. Wt% copper, 0.25 wt% bismuth, 0.7 wt% manganese, 0.004 wt% sulfur, and 0.21 wt% aluminum. After the raw materials are supplied, the non-vacuum electric furnace smelting method is used to form the Worthite iron-based alloy embryos, and then the electric slag remelting method is used to refine the Worthfield iron-based alloy embryos to form the Worthfield of the second embodiment. Iron alloy. The refining slag used in the electroslag remelting method contains 3 wt% to 20 wt% of titanium dioxide, and the refining slag may contain components of carbon difluoride, calcium oxide, magnesium oxide, aluminum oxide, and cerium oxide.

In the comparative example, the raw material was first supplied. The raw material comprises 32% by weight of nickel, 22% by weight of chromium, 0.052% by weight of carbon, 0.28% by weight of titanium, and the balance of iron and unavoidable impurities, wherein the weight ratio of titanium to carbon is about 5.4, and the impurity contains 0.4. Wt% copper, 0.28 wt% bismuth, 0.7 wt% manganese, 0.005 wt% sulfur, and 0.24 wt% aluminum. After the raw materials are supplied, the non-vacuum electric furnace smelting method is used to form the Worthite iron-based alloy embryos, and then the Vostian iron-based alloy embryos are refined by vacuum oxygen decarburization to form a comparative example of Worthfield. Iron alloy.

The tests for the anti-potential denaturation of the Worth iron-based alloys of Examples 1 and 2 and Comparative Examples were carried out. The test for anti-potential denaturation was carried out under two test conditions. Please refer to FIG. 2A. FIG. 2A is a graph showing the test results of the anti-potential denaturation of the Worthite iron-based alloys of Examples 1 and 2 and the comparative examples under the first test conditions. The first test condition is that the Examples 1 and 2 and the comparative example of Voss The field iron alloy was placed at an ambient temperature of 650 ° C and subjected to a stress of 200 MPa. From the test results, Examples 1 and 2 have superior anti-potential denaturation than the comparative examples. For more precise data, under the first test conditions, the Vostian iron-based alloy of Example 1 had a latent life of 333 hours and an elongation of 32%. The Vostian iron-based alloy of Example 2 had a creep life of 472 hours and an elongation of 33%. The Vostian iron-based alloy of the comparative example has a creep life of only 226 hours and has an elongation of only 24%.

Please refer to FIG. 2B. FIG. 2B is a graph showing the test results of the anti-potential denaturation of the Vostian iron-based alloys of Examples 1 and 2 and Comparative Examples under the second test conditions. The second test condition was that the Worthite iron alloys of Examples 1 and 2 and the comparative examples were placed at an ambient temperature of 705 ° C and subjected to a stress of 200 MPa. It is similar to the first test condition in terms of the experimental result trend, that is, Examples 1 and 2 have superior anti-potential denaturation than the comparative examples. For more precise data, under the second test condition, the Vostian iron-based alloy of Example 1 had a latent life of 17 hours and an elongation of 31%. The Vostian iron-based alloy of Example 2 had a latent life of 28 hours and had an elongation of 32%. The Vostian iron-based alloy of the comparative example has a creep life of only 11 hours and an elongation of 31%.

In order to further confirm that the Worthfield iron-based alloy of the embodiment of the present invention achieves an effect of increasing the anti-potential property by the nano-scale titanium carbide precipitate or the nitrogen-containing titanium carbide precipitate. Please refer to FIG. 3, which is a photograph of a high-resolution transmission electron microscope after the creep test of the first test condition of the Vostian iron-based alloy of Example 2 of the present invention. Wherein, the mark marked as dislocation on the graph is represented as a difference row; the mark marked as ppt. It is expressed as a nano-sized titanium carbide precipitate or a nitrogen-containing titanium carbide precipitate (the precipitate component can be analyzed by an analytical instrument such as a commercially available electron microscope); and the symbol labeled γ is expressed as a Worthite iron system. The γ phase of the substrate of the alloy. As can be seen from Fig. 3, since the precipitates are blocked, the slippage of the difference row is hindered, and the difference is partially bent, so that the precipitates surely enhance the anti-potential denaturation. On the other hand, after analyzing the precipitates having an average particle diameter of about 3 nm to 10 nm by means of selective diffraction, it is possible to obtain cubic octahedrons from the {111} and {100} crystal faces (cubo- The shape of octahedral). The image after two-dimensional Fourier Transform (FT) shows that the precipitate and the substrate are in the crystal orientation of parallel epitaxy. Thereafter, after performing an inverse Fourier Transform (IFT), the interphase interface of the γ phase of the precipitate and the substrate is maintained to maintain a coherent atomic arrangement.

The present invention has been disclosed in the above embodiments, and is not intended to limit the present invention. Any one of ordinary skill in the art to which the present invention pertains can make various changes without departing from the spirit and scope of the invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.

100‧‧‧ method

110, 120‧‧‧ steps

Claims (10)

A Worthfield iron-based alloy comprising: 5 wt% to 75 wt% of iron; 7 wt% to 75 wt% of nickel, but excluding 7 wt% to 30 wt% of nickel; 15 wt% to 25 wt% of chromium; 0.065 wt% to 0.15 Carbon of wt%; 0.5 wt% to 1.35 wt% of titanium, wherein the weight ratio of titanium to carbon is 6 to 8.5; and unavoidable impurities of more than zero and less than or equal to 2 wt%, wherein the Vostian iron system When the alloy is used at a temperature of 500 to 950 degrees Celsius, a titanium carbide precipitate having an average particle diameter of more than 0 and less than 30 nm or a precipitate of nitrogen-containing titanium carbide is precipitated. The Wostian iron-based alloy according to claim 1, wherein the nickel content is 31% by weight to 32% by weight; the chromium content is 21% by weight of chromium; and the carbon content is 0.075% by weight to 0.081% by weight; The content of the titanium is 0.59 wt% to 0.61 wt%, wherein the weight ratio of the titanium to the carbon is 7.5 to 7.8; and the iron and the impurities, wherein the impurities comprise: 0.3 wt% to 0.4 wt% of copper; 0.23 Wt% to 0.25 wt% 矽; 0.7 wt% manganese; 0.004 wt% sulfur; 0.21% by weight to 0.24% by weight of aluminum. The Vostian iron-based alloy according to claim 1, wherein the Worthite iron-based alloy precipitates a titanium carbide precipitate having an average particle diameter of more than 0 and less than 30 nm when used at 650 ° C to 705 ° C. Nitrogen titanium carbide precipitate precipitates. A method for producing a Wolsfield iron-based alloy, comprising: providing a raw material comprising: 5 wt% to 75 wt% of iron; 7 wt% to 75 wt% of nickel, but excluding 7 wt% to 30 wt% of nickel; 15 wt% To 25 wt% chromium; 0.065 wt% to 0.15 wt% carbon; 0.5 wt% to 1.35 wt% titanium, wherein the titanium to carbon weight ratio is 6 to 8.5; and greater than zero and less than or equal to 2 wt% Avoiding impurities; and subjecting the raw material to a smelting process to form the Vostian iron-based alloy, wherein the Worthfield iron-based alloy has an average particle diameter of more than 0 and less than 30 nm when used at 500 to 950 degrees Celsius A titanium carbide precipitate or a nitrogen-containing titanium carbide precipitate. The method for producing a Worthian iron-based alloy according to claim 4, wherein the raw material comprises: 31 wt% to 32 wt% nickel; 21 wt% chromium; 0.075 wt% to 0.081 wt% carbon; 0.59 wt% to 0.61 wt% titanium, wherein the titanium to carbon weight ratio is 7.5 to 7.8; Iron and unavoidable impurities, wherein the impurities comprise: 0.3 wt% to 0.4 wt% copper; 0.23 wt% to 0.25 wt% niobium; 0.7 wt% manganese; 0.004 wt% sulfur; and 0.21 wt% to 0.24 Wt% aluminum. The method for producing a Vostian iron-based alloy according to claim 4, wherein the smelting process comprises a vacuum induction melting method and a vacuum oxygen decarburization method. The method for producing a Worthite iron-based alloy according to claim 4, wherein the smelting process comprises using a non-vacuum electric furnace smelting method and an electroslag remelting method. The method for producing a Vostian iron-based alloy according to claim 7, wherein the smelting process further comprises: performing the non-vacuum electric furnace smelting method to smelt the raw material to form a Wostian iron-based alloy embryo; Performing the electroslag remelting method to form the Vostian iron-based alloy embryo into the Vostian iron-based alloy, wherein the electroslag remelting method further comprises adding the Vostian iron-based alloy embryo and a refining slag In an electroslag remelting furnace, the refining slag comprises 3 wt% to 20 wt% of titanium dioxide. The method for producing a Vostian iron-based alloy according to claim 8, wherein the component of the refining slag further comprises carbon difluoride, calcium oxide, magnesium oxide, aluminum oxide, and cerium oxide. The method for producing a Worthite iron-based alloy according to claim 4, wherein the Worthite iron-based alloy precipitates titanium carbide having an average particle diameter of more than 0 and less than 30 nm when used at 650 ° C to 705 ° C Or nitrogen-containing titanium carbide precipitates.