CN113215478B - Method for improving high-temperature oxidation resistance of super stainless steel - Google Patents

Method for improving high-temperature oxidation resistance of super stainless steel Download PDF

Info

Publication number
CN113215478B
CN113215478B CN202110530117.0A CN202110530117A CN113215478B CN 113215478 B CN113215478 B CN 113215478B CN 202110530117 A CN202110530117 A CN 202110530117A CN 113215478 B CN113215478 B CN 113215478B
Authority
CN
China
Prior art keywords
equal
ingot
percent
less
yttrium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110530117.0A
Other languages
Chinese (zh)
Other versions
CN113215478A (en
Inventor
李花兵
张树才
闻哲健
姜周华
禹江涛
冯浩
张彬彬
杨新宇
朱红春
贺彤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Northeastern University China
Original Assignee
Northeastern University China
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Northeastern University China filed Critical Northeastern University China
Priority to CN202110530117.0A priority Critical patent/CN113215478B/en
Publication of CN113215478A publication Critical patent/CN113215478A/en
Application granted granted Critical
Publication of CN113215478B publication Critical patent/CN113215478B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • C22C33/06—Making ferrous alloys by melting using master alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C30/00—Alloys containing less than 50% by weight of each constituent
    • C22C30/02—Alloys containing less than 50% by weight of each constituent containing copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese

Abstract

The invention belongs to the technical field of super stainless steel, and provides a method for improving high-temperature oxidation resistance of super stainless steel. In the present invention, silicon and yttrium readily react with oxygen to form SiO2And Y2O3，SiO2And Y2O3Can be Cr2O3Provides favorable nucleation sites and promotes fine dense Cr2O3Forming a protective layer, thereby reducing defects in the oxide layer; and fine and dense Cr2O3The formation of the protective layer can effectively improve the protection and adhesion of the oxide layer. In the pre-oxidation, silicon is easily oxidized preferentially to form dense SiO2Layer, blocking diffusion of elements, reducing MoO3Generating; yttrium is easy to be segregated in the grain boundary, so that an obvious potential barrier is formed around the grain boundary, thereby hindering the outward diffusion of large-size Mo atoms and obviously relieving MoO3Volatilization of MoO3Volatilization reduction can obviously reduce the damage effect on the oxide layer, further improve the protection of the oxide layer and effectively block the air nitriding process.

Description

Method for improving high-temperature oxidation resistance of super stainless steel
Technical Field
The invention relates to the technical field of super stainless steel, in particular to a method for improving high-temperature oxidation resistance of super stainless steel.
Background
The super stainless steel is an alloy with alloy content (Cr, Ni, Mo, N and the like) obviously higher than that of common stainless steel, has excellent corrosion resistance and good comprehensive mechanical property in extremely harsh service environments in the fields of petrochemical industry, energy conservation, environmental protection, ocean engineering and the like, and is an ideal material for replacing nickel-based alloy and titanium-based alloy. However, since the super stainless steel has a high content of molybdenum, MoO generated by oxidation of molybdenum is generated during high-temperature homogenization, hot working and heat treatment3The chromium oxide is very volatile, the integrity and the compactness of an oxide layer are damaged, the oxide layer forms a large number of cavities and cracks, the protective effect is lost, the nitrogen in the air is promoted to diffuse into a matrix, and discontinuous Cr is induced2And (4) precipitating N. Cr (chromium) component2The formation of N not only reduces the forming capability of the chromium-rich protective oxide layer, but also can be used as a rapid channel to promote the external diffusion of elements such as chromium, molybdenum and the like and the internal diffusion of oxygen and nitrogen elements. In MoO3Large amount of volatile and air nitriding induced Cr2Under the synergistic effect of N precipitation, the super stainless steel can be catastrophically oxidized, the casting blank grinding loss rate is greatly increased, and the surface quality and the corrosion resistance of the hot-rolled and cold-rolled steel plates are seriously influenced. Therefore, the search for effective suppression of drastic volatilization of molybdenum and air nitriding induced Cr2The measure of N precipitation is necessary to reduce the high-temperature oxidation loss of the super stainless steel.
Disclosure of Invention
In view of the above, the present invention provides a method for improving the high temperature oxidation resistance of super stainless steel. The method provided by the invention can improve the high-temperature oxidation resistance of the super stainless steel.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a method for improving the high-temperature oxidation resistance of super stainless steel, which comprises the following steps:
smelting a super stainless steel raw material to obtain a smelting solution; the vacuum degree of the smelting is less than or equal to 5 Pa;
mixing the smelting liquid with chromium nitride, and carrying out nitrogen alloying to obtain a molten clear liquid; the temperature of the nitrogen alloying is 1520-1550 ℃, the pressure of the nitrogen alloying is 75-85% of the target pressure of continuous bottom blowing, the pressure of the nitrogen alloying is realized by introducing bottom blowing nitrogen, and the flow rate of the bottom blowing nitrogen is 0.25-0.40 Nm3/h；
Mixing the molten clear liquid with the rare earth magnesium alloy, and sequentially carrying out deoxidation and desulfurization and continuous bottom blowing to obtain a smelting liquid; the temperature of deoxidation and desulfurization is 10-20 ℃ lower than that of nitrogen alloying; the time for deoxidation and desulfurization is 3-5 min;
the target pressure of the continuous bottom blowing is 0.03-0.10 MPa, the target pressure of the continuous bottom blowing is realized by continuously blowing nitrogen gas at a flow rate of 0.03-0.15 Nm3The continuous bottom blowing of the nitrogen is carried out for 8-12 min;
mixing the smelting liquid, industrial silicon and nickel-yttrium alloy, and carrying out silicon-yttrium alloying to obtain molten steel; the temperature of the silicon-yttrium alloying is 1520-1550 ℃;
casting the molten steel to obtain a cast ingot;
pre-oxidizing the cast ingot;
the parameters of the pre-oxidation include:
when the mass percentage content of Mo, Cr and N in the ingot is less than or equal to 0.5 (less than or equal to 3.3 Xpercent Mo/% Cr +16 Xpercent N/% Cr) and less than or equal to 1.0, the temperature of pre-oxidation is 1080-1120 ℃;
secondly, when the mass percentages of Mo, Cr and N in the ingot satisfy: the temperature of the pre-oxidation is 1120-1150 ℃ when the temperature is more than or equal to 1.1 (3.3X% Mo/% Cr + 16X% N/% Cr) less than or equal to 1.5; % is the mass percentage of the elements in the ingot;
the pre-oxidation heat preservation time t is calculated by a formula 1:
t is a × d formula 1;
in the formula 1, t is heat preservation time, and the unit is min; the value of a is 0.5-3, and the unit is min/cm; d is the diameter of the ingot in cm.
Preferably, the mass percent of chromium in the chromium nitride is more than or equal to 85 percent, and the mass percent of nitrogen is more than or equal to 10 percent; the addition amount of the chromium nitride is 16.5-52.0 kg/t.
Preferably, the rare earth magnesium alloy comprises the following components in percentage by mass: mg: 15-25%, RE: 30-45% of nickel, and the balance of nickel, wherein the RE comprises one or more of Ce, La and Gd; the addition amount of the rare earth magnesium alloy is 1.0-1.5 kg/t.
Preferably, the mass percent of O in the smelting liquid is less than or equal to 0.0015 percent, and the mass percent of S in the smelting liquid is less than or equal to 0.0010 percent.
Preferably, the mass percentage of yttrium in the nickel-yttrium alloy is 1-4%; the adding amount of the nickel-yttrium alloy is 1-8 kg/t.
Preferably, the purity of the industrial silicon is more than or equal to 99%, and the addition amount of the industrial silicon is 5.5-11.5 kg/t.
Preferably, the casting pressure is 0.10-0.13 MPa.
Preferably, the ingot comprises the following components in percentage by mass: c: less than or equal to 0.03 percent, Cr: 19.5 to 29%, Ni: 5.5-23%, Mo: 3-8%, N: 0.18 to 0.55%, Cu: 0.3-1%, Si: 0.7-1.2%, Mn: 1-4%, P: less than or equal to 0.03%, S: less than or equal to 0.005%, Y: 0.003 to 0.008 percent, and the balance of Fe and inevitable impurity elements;
simultaneously: when the mass percentage of Mo and Cr in the ingot satisfies: when the content of Mo +0.5 x% Cr is more than or equal to 15.5 and less than or equal to 17.5, the mass percentage of Si and Y in the ingot satisfies the following conditions: 1.25 percent (Si + 40X percent Y) to 1.35; when the mass percentage of Mo and Cr in the ingot satisfies: when the mass percentage of Si and Y in the ingot is less than or equal to 20.5 percent (Mo +0.5 x Cr), the mass percentage of Si and Y in the ingot satisfies the following conditions: 0.95 percent to 1.05 percent (Si + 40X percent Y); % is the mass percentage of the elements in the ingot.
The invention provides a lifting super stainless steelA method for the high temperature oxidation resistance of steel comprising the steps of: smelting a super stainless steel raw material to obtain a smelting solution; the vacuum degree of the smelting is less than or equal to 5 Pa; mixing the smelting liquid with chromium nitride, and carrying out nitrogen alloying to obtain a molten clear liquid; the temperature of the nitrogen alloying is 1520-1550 ℃, the pressure of the nitrogen alloying is 75-85% of the target pressure of continuous bottom blowing, the pressure of the nitrogen alloying is realized by introducing bottom blowing nitrogen, and the flow rate of the bottom blowing nitrogen is 0.25-0.40 Nm3H; mixing the molten clear liquid with the rare earth magnesium alloy, and sequentially carrying out deoxidation and desulfurization and continuous bottom blowing to obtain a smelting liquid; the temperature of deoxidation and desulfurization is 10-20 ℃ lower than that of nitrogen alloying; the time for deoxidation and desulfurization is 3-5 min; the target pressure of the continuous bottom blowing is 0.03-0.10 MPa, the target pressure of the continuous bottom blowing is realized by continuously blowing nitrogen gas at a flow rate of 0.03-0.15 Nm3The continuous bottom blowing of the nitrogen is carried out for 8-12 min; mixing the smelting liquid, industrial silicon and nickel-yttrium alloy, and carrying out silicon-yttrium alloying to obtain molten steel; the temperature of the silicon-yttrium alloying is 1520-1550 ℃; casting the molten steel to obtain a cast ingot; pre-oxidizing the cast ingot; the parameters of the pre-oxidation include: when the mass percentage content of Mo, Cr and N in the ingot is less than or equal to 0.5 (less than or equal to 3.3 Xpercent Mo/% Cr +16 Xpercent N/% Cr) and less than or equal to 1.0, the temperature of pre-oxidation is 1080-1120 ℃; secondly, when the mass percentages of Mo, Cr and N in the ingot satisfy: the temperature of the pre-oxidation is 1120-1150 ℃ when the temperature is more than or equal to 1.1 (3.3X% Mo/% Cr + 16X% N/% Cr) less than or equal to 1.5; % is the mass percentage of the elements in the ingot; the pre-oxidation heat preservation time t is calculated by a formula 1: t is a × d formula 1; in the formula 1, t is heat preservation time, and the unit is min; the value of a is 0.5-3, and the unit is min/cm; d is the diameter of the ingot in cm.
The invention adopts industrial silicon and nickel-hundred million alloy to carry out silicon-yttrium alloying, and the silicon and the yttrium react with oxygen most easily to generate SiO2And Y2O3. These preferentially formed SiO2And Y2O3Can be Cr2O3Provide favorable nucleation sites, promote fine densificationCr2O3And forming a protective layer, thereby reducing defects in the oxide layer. In the pre-oxidation process, silicon is easily preferentially oxidized to form dense SiO2Layer, blocking diffusion of elements, reducing MoO3Generating; yttrium is easy to be segregated in the grain boundary, so that an obvious potential barrier is formed around the grain boundary, thereby hindering the outward diffusion of large-size Mo atoms and obviously relieving MoO3And (6) volatilizing. Fine and dense Cr2O3The formation of the protective layer can effectively improve the protection and adhesion of the oxide layer, MoO3The volatilization reduction can obviously reduce the damage effect on the oxide layer, further improve the protection of the oxide layer and effectively block the air nitriding process. In addition, the pre-oxidation can promote the selective oxidation of silicon and yttrium, and further improve the compactness and the adhesion of an oxidation layer. In conclusion, the silicon-yttrium synergistic effect and the preoxidation treatment can effectively improve the protection and adhesion of the oxide layer and inhibit MoO3Large amount of volatile and air nitriding induced Cr2N is separated out, and the high-temperature oxidation resistance of the super stainless steel is obviously improved.
Furthermore, the addition of silicon and yttrium is reasonably set, the precipitation sensitivity of steel is reduced, and harmful secondary phases are prevented from being precipitated; secondly, before silicon-yttrium alloying, the molten clear liquid is deoxidized and desulfurized, the floating of inclusions is promoted by bottom blowing nitrogen, the O, S content in the smelting liquid is reduced, yttrium element is added in combination with the form of nickel-yttrium alloy, the alloying degree of silicon and yttrium is improved to the maximum extent, the yield of silicon-yttrium is respectively up to more than 98% and 70%, and the synergistic antioxidation effect of silicon-yttrium is more favorably exerted.
Furthermore, the proper contents of silicon and yttrium and the pre-oxidation temperature are selected according to the specific components of the super stainless steel, so that the compactness and the adhesiveness of an oxide layer are enhanced, the high-temperature oxidation resistance is improved, the precipitation sensitivity of the steel is reduced, and a large amount of harmful phases are prevented from being precipitated.
Drawings
FIG. 1 is a photograph of the surface topography of example Steel grade No. 1 after oxidation at 1200 ℃ for 2 h;
FIG. 2 is a photograph of the surface morphology of comparative example steel grade No. 5 after oxidation at 1200 ℃ for 2 h;
FIG. 3 is a photograph of the surface topography of example Steel grade No. 2 after oxidation at 1200 ℃ for 2 h;
FIG. 4 is a photograph of the surface morphology of comparative example steel grade No. 6 after oxidation at 1200 ℃ for 2 h;
FIG. 5 is a photograph of the surface topography of example Steel grade No. 3 after oxidation at 1200 ℃ for 2 h;
FIG. 6 is a photograph of the surface morphology of comparative example steel grade No. 7 after oxidation at 1200 ℃ for 2 h;
FIG. 7 is a photograph of the surface topography of example Steel grade No. 4 after oxidation at 1200 ℃ for 2 h;
FIG. 8 is a photograph of the surface morphology of comparative example steel grade No. 8 after oxidation at 1200 ℃ for 2 h.
Detailed Description
The invention provides a method for improving the high-temperature oxidation resistance of super stainless steel, which comprises the following steps:
smelting a super stainless steel raw material to obtain a smelting solution;
mixing the smelting liquid with chromium nitride, and carrying out nitrogen alloying to obtain a molten clear liquid;
mixing the molten clear liquid with the rare earth magnesium alloy, and sequentially carrying out deoxidation and desulfurization and continuous bottom blowing to obtain a smelting liquid;
mixing the smelting liquid, industrial silicon and nickel-yttrium alloy, and carrying out silicon-yttrium alloying to obtain molten steel;
casting the molten steel to obtain a cast ingot;
and pre-oxidizing the cast ingot.
The invention smelts the super stainless steel raw material to obtain the smelting liquid.
In the invention, the pressure of the smelting is less than or equal to 5 Pa. The parameters of the smelting temperature, the smelting time and the like are not particularly limited, and the smelting temperature and the smelting time which are well known to those skilled in the art can be adopted. In the present invention, the melting is preferably performed in a vacuum induction furnace.
After the smelting liquid is obtained, the smelting liquid and chromium nitride are mixed for nitrogen alloying to obtain a molten clear liquid.
In the invention, the mass percentage of chromium in the chromium nitride is preferably not less than 85%, and the mass percentage of nitrogen is preferably not less than 10%. In the invention, the addition amount of the chromium nitride is preferably 16.5-52.0 kg/t, and more preferably 18.0-46.0 kg/t.
In the invention, the pressure of nitrogen alloying is 75-85% of the target pressure of continuous bottom blowing, and is preferably 80%; the target pressure of the continuous bottom blowing is described in detail in the relevant section below. In the present invention, the pressure of the nitrogen alloying is preferably controlled by bottom blowing nitrogen gas; the flow rate of the bottom blowing nitrogen is 0.25-0.40 Nm3H is used as the reference value. In the invention, the temperature of nitrogen alloying is preferably 1520-1550 ℃, more preferably 1528-1543 ℃, and even more preferably 1531-1538 ℃. The time for the nitrogen alloying is not particularly limited, as long as the molten steel system can be melted down.
After obtaining the molten clear liquid, mixing the molten clear liquid with the rare earth magnesium alloy, and sequentially carrying out deoxidation and desulfurization and continuous bottom blowing to obtain the smelting liquid.
In the invention, the rare earth magnesium alloy preferably comprises the following components in percentage by mass: mg: 15-25%, RE: 30-45% of nickel, and the balance of nickel. In the invention, the rare earth magnesium alloy comprises 15-25% by mass of magnesium, more preferably 15.24-24.35%, and still more preferably 18.74-20.36%. In the invention, the rare earth magnesium alloy comprises 30-45% by mass of RE, more preferably 30.8-40.4%, and even more preferably 31.75-35.67%. In the invention, the RE is preferably one or more of Ce, La and Gd, and is particularly preferably Gd, a mixture of Ce and La, a mixture of Ce and Gd, and a mixture of Ce, La and Gd. In the invention, the addition amount of the rare earth magnesium alloy is preferably 1.0-1.5 kg/t, more preferably 1.1-1.4 kg/t, and even more preferably 1.2-1.3 kg/t.
In the invention, the temperature of deoxidation and desulfurization is 10-20 ℃ lower than the temperature of nitrogen alloying, preferably 13-18 ℃ lower, and further preferably 15 ℃ lower; the time for deoxidation and desulfurization is preferably 3-5 min.
In the invention, the target pressure of the continuous bottom blowing is 0.03-0.10 MPa, preferably 0.035-0.1 MPa, and further preferably 0.05-0.08 MPa; the mesh of the continuous bottom blowingThe standard pressure is controlled by continuously blowing nitrogen at the bottom, and the flow rate of the continuously blowing nitrogen at the bottom is 0.03-0.15 Nm3Preferably 0.033 to 0.14 Nm/h3More preferably 0.05 to 0.09 Nm/h3H; the time for continuously blowing the nitrogen at the bottom is preferably 8-12 min.
After the smelting liquid is obtained, the smelting liquid, industrial silicon and nickel-yttrium alloy are mixed for silicon-yttrium alloying to obtain molten steel.
In the present invention, the purity of the industrial silicon is preferably 99% or more. In the invention, the addition amount of the industrial silicon is preferably 5.5-11.5 kg/t, and more preferably 6.5-11.2 kg/t.
In the invention, the mass percentage of yttrium in the nickel-yttrium alloy is preferably 1-4%, more preferably 1.08-3.87%, and even more preferably 1.65-3.23%. In the invention, the addition amount of the nickel-yttrium alloy is preferably 1-8 kg/t, and more preferably 2.0-6.5 kg/t.
In the invention, the temperature of the silicon-yttrium alloying is 1520-1550 ℃, preferably 1526-1545 ℃, and more preferably 1532-1536 ℃. The time for alloying silicon with yttrium is not particularly limited, as long as the molten steel system can be melted down.
In the invention, the mass percent of O in the molten steel is less than or equal to 0.0015 percent, and the mass percent of S in the molten steel is less than or equal to 0.0010 percent.
After molten steel is obtained, the molten steel is cast to obtain cast ingots.
In the invention, the casting pressure is preferably 0.10-0.13 MPa, and more preferably 0.11-0.12 MPa; the casting is preferably carried out under a protective atmosphere, preferably nitrogen. In the present invention, the casting is preferably performed in a vacuum induction furnace.
In the invention, the ingot preferably comprises the following components in percentage by weight:
c: less than or equal to 0.03 percent, Cr: 19.5 to 29%, Ni: 5.5-23%, Mo: 3-8%, N: 0.18 to 0.55%, Cu: 0.3-1%, Si: 0.7-1.2%, Mn: 1-4%, P: less than or equal to 0.03%, S: less than or equal to 0.005%, Y: 0.003 to 0.008 percent, and the balance of Fe and inevitable impurity elements; simultaneously:
when the mass percentage of Mo and Cr in the ingot satisfies: when the content of Mo +0.5 x% Cr is more than or equal to 15.5 and less than or equal to 17.5, the mass percentage of Si and Y in the ingot satisfies the following conditions: 1.25 percent (Si + 40X percent Y) to 1.35; when the mass percentage of Mo and Cr in the ingot satisfies: when the mass percentage of Si and Y in the ingot is less than or equal to 20.5 percent (Mo +0.5 x Cr), the mass percentage of Si and Y in the ingot satisfies the following conditions: 0.95 percent to 1.05 percent (Si + 40X percent Y), and the percent is the mass percent of elements in the ingot.
After the ingot is obtained, the ingot is sequentially pre-oxidized.
In the present invention, the parameters of the pre-oxidation include:
when the mass percentage content of Mo, Cr and N in the ingot is less than or equal to 0.5 (less than or equal to 3.3 Xpercent Mo/% Cr +16 Xpercent N/% Cr) and less than or equal to 1.0, the temperature of pre-oxidation is 1080-1120 ℃; % is the mass percentage of the elements in the ingot.
Secondly, when the mass percentages of Mo, Cr and N in the ingot satisfy: the temperature of the pre-oxidation is 1120-1150 ℃ when the temperature is more than or equal to 1.1 (3.3X% Mo/% Cr + 16X% N/% Cr) less than or equal to 1.5; % is the mass percentage of the elements in the ingot.
In the invention, the pre-oxidation holding time t is calculated by formula 1:
t is a × d formula 1;
in the formula 1, t is heat preservation time, and the unit is min; the value range of a is 0.5-3, and the unit is min/cm; d is the diameter of the ingot in cm.
After the ingot is pre-oxidized, the invention preferably can also perform high-temperature homogenization and thermal processing on the pre-oxidized ingot in sequence.
The parameters of the high temperature homogenization and thermal processing are not particularly limited in the present invention, and those well known to those skilled in the art can be used.
The method for improving the high temperature oxidation resistance of super stainless steel provided by the present invention is described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.
EXAMPLE 1 preparation of super stainless Steel
In the embodiment of the invention, the smelting equipment is a 200kg vacuum induction furnace, the charging amount is 160kg, the smelting steel is four super stainless steels (1# -4 #) with different components, and the main components of the used smelting raw materials are shown in tables 1 and 2.
TABLE 1 Main ingredient of smelting raw materials (wt.%)
Species of Si Cr Ni Mn Mo C S P N Cu Fe
Industrial pure iron 0.006 0.024 0.009 0.022 - 0.0018 0.0032 0.0081 - - 99.90
Electrolytic manganese 0.007 - - 99.80 0.036 0.0330 0.0035 - - 0.019
Metallic chromium 0.17 99.32 - - - 0.006 0.0008 ≤0.003 0.005 - 0.14
Electrolytic nickel 0.0012 - 99.987 0.0005 - 0.0023 - - - - -
Metallic molybdenum 0.0007 - 0.0031 - 99.98 0.001 - 0.001 0.0001 - 0.0045
Industrial silicon 99.37 - - - - - - ≤0.3 - - ≤0.3
Electrolytic copper - - 0.002 - - - 0.0025 0.001 - 99.95 0.0025
Chromium nitride 0.18 86.58 - - - 0.016 0.001 0.005 11.26 - 0.27
Table 2 rare earth magnesium alloy and nickel yttrium alloy main components (wt.%)
Figure BDA0003067289740000081
The method comprises the following specific steps:
(1) material preparation and charging: placing industrial pure iron, metallic chromium, metallic molybdenum, metallic nickel, electrolytic copper and metallic manganese in a crucible of an induction furnace, placing high-purity chromium nitride, rare earth magnesium alloy, industrial silicon and nickel yttrium alloy in a feeding bin, and taking the raw materials used for smelting four-furnace super stainless steel as shown in Table 3;
TABLE 3 raw materials (kg) for smelting 1# -4 # super stainless steel
Figure BDA0003067289740000082
Figure BDA0003067289740000091
(2) Smelting: vacuumizing the induction furnace to below 5Pa, electrifying, heating and starting smelting;
(3) nitrogen alloying, deoxidation and desulfurization and continuous bottom blowing: controlling the temperature T of the molten steel after the furnace charge in the crucible is completely melted1Stabilized at 1520-1550 ℃, nitrogen is filled into the furnace through a ventilation plug at the bottom of the crucible to reach the pressure P1(0.025 to 0.08MPa) and the flow rate is controlled to 0.25 to 0.40Nm3Then adding chromium nitride for further nitrogen alloying; then, the temperature T of the molten steel is controlled2Adding rare earth magnesium alloy to the temperature of 1500-1530 ℃, carrying out deoxidation and desulfurization treatment, and continuously blowing nitrogen from bottom to smelting pressure P after 3-5 min2(0.03-0.10 MPa), the flow rate is controlled to be 0.03-0.15 Nm3The bottom blowing time is controlled to be 8-12 min;
(4) silicon yttrium alloying: after the bottom blowing is finished, controlling the temperature T of the molten steel3Stabilizing at 1520-1550 ℃, and adding industrial silicon and nickel-yttrium alloy into the molten steel to perform silicon-yttrium alloying;
(5) casting: filling nitrogen into the vacuum induction furnace to a casting pressure P3(0.10-0.13 MPa), casting, breaking vacuum after casting, and taking out the cast ingot;
the specific process parameters of the 1# to 4# super stainless steel smelting process are shown in Table 4.
Table 41# to 4# super stainless steel specific smelting process parameters
Figure BDA0003067289740000092
Figure BDA0003067289740000101
Example 2 super stainless Steel composition analysis
The chemical analysis method is used for analyzing the components of the 1# to 8# super stainless steel, and the results are shown in table 5, wherein 1# to 4# are steel grades of the embodiment of the invention, and 5# to 8# are steel grades of the comparative example, namely the commercial super stainless steel with the same grade.
TABLE 51# 8# super stainless steel composition analysis results (wt.%) and
Figure BDA0003067289740000102
Figure BDA0003067289740000111
as can be seen from Table 5, the O, S content of the steel grades of the examples No. 1 to No. 4 of the invention is significantly lower than that of the steel grades of the comparative examples No. 5 to No. 8 of the invention, which shows that the invention realizes the ultra-low oxygen sulfur control of the super stainless steel. In addition, the yield of silicon and yttrium of the steel grade of the embodiment 1# to 4# is very high, the silicon yield is as high as 98.2-99.7%, and the yttrium yield is as high as 71.2-78.8%, which shows that the invention adopts rare earth magnesium alloy for deep deoxidation and desulfurization, and then silicon and nickel yttrium alloy are added for silicon yttrium alloying, so that the problem of burning loss of silicon and yttrium in the smelting process can be obviously reduced, and the yield of the silicon and yttrium can be obviously improved.
Example 3 high temperature Oxidation resistance
Cut out a phi 15cm x 5cm circular sample perpendicularly to the height direction on the ingots of inventive example steel grades 1# to 4# and comparative example steel grades 5# to 8# and each surface was sanded stepwise with sandpaper and then weighed. The 1# to 4# samples were first pre-oxidized, then oxidized at constant temperatures of 1000 ℃ and 1200 ℃ for 2 hours with the 5# to 8# samples, after the experiment was completed, the samples were cooled and weighed, and the weight increase per unit surface area was calculated, and the corresponding pre-oxidation treatment regime and the weight increase per unit surface area oxidation were shown in table 6.
Table 61# 8# super stainless steel high temperature oxidation experimental result
Figure BDA0003067289740000112
Figure BDA0003067289740000121
As can be seen from table 6: the oxidation weight gain of the steel grades of the 1# to 4# embodiments of the invention is obviously lower than that of the corresponding steel grades of the 5# to 8# comparative examples at two temperatures: compared with 5# 8# steel grades, the 1# 4# steel grades respectively reduce the weight gains per unit surface area at 1000 ℃ by 53.15%, 55.36%, 51.02% and 51.98%, and respectively reduce the weight gains per unit surface area at 1200 ℃ by 54.67%, 56.79%, 52.76% and 53.85%. The implementation of the method of the invention can reduce the oxidation burning loss of the super stainless steel by more than one time.
FIGS. 1 to 8 show the surface appearances of example No. 1 to 4 steel grades and comparative example No. 5 to 8 steel grades of the invention after being oxidized for 2 hours at 1200 ℃, and it can be seen from FIGS. 1 to 8 that: the compactness of the oxidation layer of the 1# to 4# steel grade is obviously higher than that of the 5# to 8# steel grade, and the results further show that the method provided by the invention obviously improves the high-temperature oxidation resistance of the super stainless steel.
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.

Claims (8)

1. A method for improving the high-temperature oxidation resistance of super stainless steel comprises the following steps:
smelting a super stainless steel raw material to obtain a smelting solution; the vacuum degree of the smelting is less than or equal to 5 Pa;
mixing the smelting liquid with chromium nitrideMixing, carrying out nitrogen alloying to obtain molten clear liquid; the temperature of the nitrogen alloying is 1520-1550 ℃, the pressure of the nitrogen alloying is 75-85% of the target pressure of continuous bottom blowing, the pressure of the nitrogen alloying is realized by introducing bottom blowing nitrogen, and the flow rate of the bottom blowing nitrogen is 0.25-0.40 Nm3/h；
Mixing the molten clear liquid with the rare earth magnesium alloy, and sequentially carrying out deoxidation and desulfurization and continuous bottom blowing to obtain a smelting liquid; the temperature of deoxidation and desulfurization is 10-20 ℃ lower than that of nitrogen alloying; the time for deoxidation and desulfurization is 3-5 min;
the target pressure of the continuous bottom blowing is 0.03-0.10 MPa, the target pressure of the continuous bottom blowing is realized by continuously blowing nitrogen gas at a flow rate of 0.03-0.15 Nm3The continuous bottom blowing of the nitrogen is carried out for 8-12 min;
mixing the smelting liquid, industrial silicon and nickel-yttrium alloy, and carrying out silicon-yttrium alloying to obtain molten steel; the temperature of the silicon-yttrium alloying is 1520-1550 ℃;
casting the molten steel to obtain a cast ingot;
pre-oxidizing the cast ingot;
the raw materials of the super stainless steel comprise industrial pure iron, metallic chromium, metallic molybdenum, metallic nickel, electrolytic copper and metallic manganese;
the parameters of the pre-oxidation include:
when the mass percentage content of Mo, Cr and N in the ingot is more than or equal to 0.5 (3.3X% Mo/% Cr + 16X% N/% Cr) and less than or equal to 1.0, the pre-oxidation temperature is 1080-1120 ℃;
secondly, when the mass percentages of Mo, Cr and N in the ingot satisfy: when the temperature is more than or equal to 1.1 and less than or equal to (3.3 Xpercent Mo/% Cr +16 Xpercent N/% Cr) and less than or equal to 1.5, the pre-oxidation temperature is 1120-1150 ℃; % is the mass percentage of the elements in the ingot;
the pre-oxidation heat preservation time t is calculated by a formula 1:
t=a×dformula 1;
in the formula 1, t is heat preservation time, and the unit is min;athe value of (a) is 0.5-3, and the unit is min/cm;dis the diameter of the ingot in cm.
2. The method according to claim 1, wherein the mass percent of chromium in the chromium nitride is more than or equal to 85%, and the mass percent of nitrogen is more than or equal to 10%; the addition amount of the chromium nitride is 16.5-52.0 kg/t.
3. The method according to claim 1, wherein the rare earth magnesium alloy comprises the following components in percentage by mass: mg: 15-25%, RE: 30-45% of nickel, and the balance of nickel, wherein the RE comprises one or more of Ce, La and Gd; the addition amount of the rare earth magnesium alloy is 1.0-1.5 kg/t.
4. The method according to claim 1, wherein the mass percentage of O in the smelting liquid is less than or equal to 0.0015%, and the mass percentage of S in the smelting liquid is less than or equal to 0.0010%.
5. The method according to claim 1, wherein the mass percent of yttrium in the nickel-yttrium alloy is 1-4%; the adding amount of the nickel-yttrium alloy is 1-8 kg/t.
6. The method according to claim 1, wherein the purity of the industrial silicon is more than or equal to 99%, and the addition amount of the industrial silicon is 5.5-11.5 kg/t.
7. The method according to claim 1, wherein the casting pressure is 0.10-0.13 MPa.
8. The method of claim 1 or 7, wherein the ingot comprises the following components in percentage by mass: c: less than or equal to 0.03 percent, Cr: 19.5 to 29%, Ni: 5.5-23%, Mo: 3-8%, N: 0.18 to 0.55%, Cu: 0.3-1%, Si: 0.7-1.2%, Mn: 1-4%, P: less than or equal to 0.03%, S: less than or equal to 0.005%, Y: 0.003 to 0.008 percent, and the balance of Fe and inevitable impurity elements;
simultaneously:
when the mass percentage of Mo and Cr in the ingot satisfies: when the content of Mo +0.5 x% Cr is more than or equal to 15.5 and less than or equal to 17.5, the mass percentage of Si and Y in the ingot satisfies the following conditions: 1.25 percent (Si + 40X percent Y) to 1.35; when the mass percentage of Mo and Cr in the ingot satisfies: when the mass percentage of Si and Y in the ingot is less than or equal to 20.5 percent (Mo +0.5 x Cr), the mass percentage of Si and Y in the ingot satisfies the following conditions: 0.95 percent to 1.05 percent (Si + 40X percent Y); % is the mass percentage of the elements in the ingot.
CN202110530117.0A 2021-05-14 2021-05-14 Method for improving high-temperature oxidation resistance of super stainless steel Active CN113215478B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110530117.0A CN113215478B (en) 2021-05-14 2021-05-14 Method for improving high-temperature oxidation resistance of super stainless steel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110530117.0A CN113215478B (en) 2021-05-14 2021-05-14 Method for improving high-temperature oxidation resistance of super stainless steel

Publications (2)

Publication Number Publication Date
CN113215478A CN113215478A (en) 2021-08-06
CN113215478B true CN113215478B (en) 2022-03-04

Family

ID=77092067

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110530117.0A Active CN113215478B (en) 2021-05-14 2021-05-14 Method for improving high-temperature oxidation resistance of super stainless steel

Country Status (1)

Country Link
CN (1) CN113215478B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115058632B (en) * 2022-06-20 2023-05-12 东北大学 Method for improving solidification structure of super austenitic stainless steel

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5302214A (en) * 1990-03-24 1994-04-12 Nisshin Steel Co., Ltd. Heat resisting ferritic stainless steel excellent in low temperature toughness, weldability and heat resistance
EP0818552A2 (en) * 1996-07-13 1998-01-14 Schmidt + Clemens GmbH + Co. Ferritic-austenitic stainless steel casting alloy
CN104379790A (en) * 2012-07-13 2015-02-25 新日铁住金不锈钢株式会社 Ferritic stainless steel sheet and method for producing ferritic stainless steel sheet with oxide coating film having excellent conductivity and adhesion
CN106636858A (en) * 2016-10-24 2017-05-10 江苏星火特钢有限公司 Method for producing high-anticorrosive high-nitrogen super austenitic stainless steel
CN108396223A (en) * 2018-03-29 2018-08-14 东北大学 A kind of super austenitic stainless steel and its alloying component optimum design method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5302214A (en) * 1990-03-24 1994-04-12 Nisshin Steel Co., Ltd. Heat resisting ferritic stainless steel excellent in low temperature toughness, weldability and heat resistance
EP0818552A2 (en) * 1996-07-13 1998-01-14 Schmidt + Clemens GmbH + Co. Ferritic-austenitic stainless steel casting alloy
CN104379790A (en) * 2012-07-13 2015-02-25 新日铁住金不锈钢株式会社 Ferritic stainless steel sheet and method for producing ferritic stainless steel sheet with oxide coating film having excellent conductivity and adhesion
CN106636858A (en) * 2016-10-24 2017-05-10 江苏星火特钢有限公司 Method for producing high-anticorrosive high-nitrogen super austenitic stainless steel
CN108396223A (en) * 2018-03-29 2018-08-14 东北大学 A kind of super austenitic stainless steel and its alloying component optimum design method

Also Published As

Publication number Publication date
CN113215478A (en) 2021-08-06

Similar Documents

Publication Publication Date Title
CN111500917A (en) High-strength and high-toughness medium-entropy high-temperature alloy and preparation method thereof
CN1796587A (en) Orientating silicon steel, manufacturing process and equipment
CN108220748A (en) The manufacturing method of household electrical appliances cold rolling low-carbon glassed steel
CN109112423A (en) Special thick alloy-steel plate of a kind of superior low-temperature toughness and preparation method thereof
CN105624562B (en) Steel for ultra-high-strength sucker rod and production method thereof
CN111394639A (en) Manufacturing method of high-wear-resistance gear steel
CN113774281A (en) 2000 MPa-grade high-ductility high-corrosion-resistance maraging stainless steel and preparation method thereof
CN104264053B (en) The neodymium iron boron production method of pure iron as raw material bar
CN111321348B (en) L-shaped steel of rib plate for LNG ship and manufacturing method thereof
CN109554609B (en) Surface peeling-free austenitic heat-resistant steel and manufacturing method thereof
CN113215478B (en) Method for improving high-temperature oxidation resistance of super stainless steel
CN109680206B (en) High-temperature-resistant iron-chromium-aluminum alloy and preparation method thereof
CN113088761B (en) Ultrahigh-strength corrosion-resistant alloy and manufacturing method thereof
CN112708826B (en) 9% Ni steel suitable for super-thick section improvement type and preparation method thereof
CN103667928B (en) A kind of anti-low temperature brittleness N80 level oil tube steel and manufacture method thereof
CN112831715A (en) Smelting method of ultrahigh manganese steel containing rare earth and having ultrahigh purity
CN114752864B (en) Low-density ultrahigh-strength high-plasticity steel and preparation method and application thereof
CN110172638B (en) High-temperature carburized gear steel and production method thereof
CN108220799A (en) Household electrical appliances cold rolling low-carbon glassed steel
CN114635077A (en) Super austenitic stainless steel and preparation method thereof
CN113774291A (en) Ultra-low carbon high-performance maraging stainless steel and preparation method thereof
CN112063928A (en) High-hardenability and high-carburization rare earth CrMnTi gear steel and preparation method thereof
CN112795836A (en) Method for reducing aluminum nitride inclusions in low-density steel through titanium treatment
WO2024017347A1 (en) Non-oriented electrical steel sheet and manufacturing method therefor
CN115058632B (en) Method for improving solidification structure of super austenitic stainless steel

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant