CN112695151A - Method for obtaining solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and preparation method - Google Patents

Method for obtaining solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and preparation method Download PDF

Info

Publication number
CN112695151A
CN112695151A CN202011502382.XA CN202011502382A CN112695151A CN 112695151 A CN112695151 A CN 112695151A CN 202011502382 A CN202011502382 A CN 202011502382A CN 112695151 A CN112695151 A CN 112695151A
Authority
CN
China
Prior art keywords
nitrogen
stainless steel
austenitic stainless
pressure
solidification
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.)
Granted
Application number
CN202011502382.XA
Other languages
Chinese (zh)
Other versions
CN112695151B (en
Inventor
李花兵
朱红春
冯浩
姜周华
何志禹
毛东升
张树才
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 CN202011502382.XA priority Critical patent/CN112695151B/en
Publication of CN112695151A publication Critical patent/CN112695151A/en
Application granted granted Critical
Publication of CN112695151B publication Critical patent/CN112695151B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/005—Manufacture of stainless steel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D2/00—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass
    • B22D2/006—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass for the temperature of the molten metal
    • 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
    • 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
    • C22C38/02—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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
    • C22C38/44—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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C2300/00—Process aspects
    • C21C2300/06—Modeling of the process, e.g. for control purposes; CII
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Investigating And Analyzing Materials By Characteristic Methods (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

The invention provides a method for acquiring solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and a preparation method, and belongs to the technical field of preparation of high-nitrogen austenitic stainless steel. The acquisition method of the invention refers to the component segregation, the nitrogen solubility and the cooling rate in the pressure induction smelting process, obtains the accurate solidification pressure, and can effectively solve the problems of nitrogen escape and nitrogen pore formation in the solidification process and improve the quality of the high-nitrogen austenitic stainless steel by utilizing the solidification pressure to prepare the high-nitrogen austenitic stainless steel.

Description

Method for obtaining solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and preparation method
Technical Field
The invention relates to the technical field of high-nitrogen austenitic stainless steel smelting, in particular to a method for acquiring solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and a preparation method.
Background
The high-nitrogen austenitic stainless steel has a plurality of unique advantages of high strength, good toughness, no magnetism, good corrosion resistance, good biocompatibility and the like, can be used for preparing basic parts such as retaining rings, armors, non-magnetic drill collars, exhaust valves of automobile engines, cardiovascular supports and the like of military large-scale gas turbines such as aircraft carriers and submarines, has a very wide application prospect, and is one of key materials for upgrading and upgrading basic materials in China.
Nitrogen pressure smelting has hitherto been considered as one of the most promising high nitrogen steel production methods, and is the only production means, especially for the production of high quality austenitic stainless steels with higher nitrogen content (about 1%). Because the solubility of nitrogen in molten steel is limited and the solubility of nitrogen in the solid phase and the liquid phase are greatly different, the defects of nitrogen escape, nitrogen hole formation and the like are easily caused in the preparation process, and the preparation problems of low component hit rate, poor structure performance and the like of high-nitrogen steel are caused. The pressure induction melting is one of important means for preparing the high-nitrogen austenitic stainless steel, and the preparation of higher-grade high-strength high-nitrogen austenitic stainless steel such as P900N, P900NMo, P2000 and the like can be realized. The solidification pressure is one of the key process parameters of the pressurized induction smelting, and is important for nitrogen preservation, nitrogen hole generation inhibition and the like in the solidification process.
For high-nitrogen austenitic stainless steel, the metallurgical reaction temperature is high, so that the pressurizing difficulty is high, and the requirement on smelting equipment is strict. In the process of preparing the high-nitrogen austenitic stainless steel by pressure induction, the equipment loss can be accelerated by the excessively high solidification pressure, the production cost is increased, production accidents are easily induced, and the production safety and the smooth operation are influenced; on the contrary, the solidification pressure is too low, which can not effectively prevent nitrogen from escaping and inhibit nitrogen pores, and even cause direct scrapping of the material, and the preparation of the high-nitrogen austenitic stainless steel with uniform nitrogen components and compact solidification structure and excellent performance is difficult to realize.
Therefore, the method for determining the solidification pressure required by inhibiting nitrogen pore formation in the high-nitrogen austenitic stainless steel prepared by pressure induction is found, the minimum value of the solidification pressure is accurately predicted, and the method is the key for solving the preparation technical problems of nitrogen escape, nitrogen pore formation and the like in the solidification process of the high-nitrogen austenitic stainless steel.
Disclosure of Invention
In view of the above, the present invention aims to provide a method for obtaining a solidification pressure required for preparing a high nitrogen austenitic stainless steel by pressure induction and a preparation method thereof. The high-nitrogen austenitic stainless steel prepared by the solidification pressure obtained by the acquisition method provided by the invention can effectively solve the problems of nitrogen escape and nitrogen pore formation in the solidification process, and the quality of the high-nitrogen austenitic stainless steel is improved.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a method for acquiring solidification pressure required by preparing high-nitrogen austenitic stainless steel by pressure induction, which comprises the following steps of:
obtaining the cooling rate vcMaximum macrosegregation ratio of nitrogen SrmaxNitrogen diffusion coefficient DsNitrogen solute distribution coefficient k, solidus temperature TSAnd liquidus temperature TL；
Obtaining a nitrogen macrosegregation parameter M according to the formula (1)N；
Figure BDA0002843986080000021
Wherein [% N ] is the mass percentage of N element in the high-nitrogen austenitic stainless steel;
the activity of nitrogen element is obtained by the formula (2)
Figure BDA0002843986080000022
Figure BDA0002843986080000023
In the formula:
Figure BDA0002843986080000024
is the interaction coefficient of nitrogen element to nitrogen element;
Figure BDA0002843986080000025
is the first order interaction coefficient of element j to nitrogen element;
Figure BDA0002843986080000026
is the secondary interaction parameter of element j to nitrogen, [% j]The mass percentage of element j in the high-nitrogen austenitic stainless steel is shown;
obtaining the required solidification pressure P of the high-nitrogen austenitic stainless steel through a formula (3)S：
Figure BDA0002843986080000027
In the formula: pθIs at standard atmospheric pressure;
the high-nitrogen austenitic stainless steel comprises the following elements in percentage by mass:
c: less than or equal to 0.2 percent, Mn: 13-20%, Cr: 15-22%, Si: less than or equal to 1 percent, Mo: 0-4.5%, N: 0.7-2%, Ni: 0-4% and the balance Fe.
Preferably, said obtaining a cooling rate vcThe method comprises the following steps:
smelting raw materials with the same components as the high-nitrogen austenitic stainless steel are placed in a pressurized induction furnace for smelting, and then electrolytic aluminum is added to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to 0.8-1.2 MPa, and pouring the smelting solution into a cylindrical casting mold to obtain a high-nitrogen austenitic stainless steel ingot;
measuring the cooling rate during casting, i.e. the cooling rate vc。
Preferably, the step of determining the cooling rate during casting comprises the steps of:
two through holes which vertically penetrate through the side wall of the casting mold are respectively drilled on the outer wall of the cylindrical casting mold at a height of 160mm from the bottom along the circumferential direction, the through holes are respectively a first through hole and a second through hole, the diameter of each through hole is 7mm independently, and the distance between the two through holes is 30mm according to the adjacent edges of the two holes on the outer wall of the casting mold; the first thermocouple and the second thermocouple are arranged in the first through hole and the second through hole, and the radial distances between the temperature points of the first thermocouple and the second thermocouple and the inner wall of the cylindrical casting mold are respectively 10mm and 15 mm;
recording the temperature variation of the molten liquid measured by the first thermocouple and the second thermocouple within a certain time in the solidification process, calculating to obtain a first cooling speed and a second cooling speed, and calculating the average value of the two cooling speeds as the cooling speed vc。
Preferably, the maximum macrosegregation ratio Sr of the obtained nitrogenmaxThe method comprises the following steps:
and (3) longitudinally planing the high-nitrogen austenitic stainless steel ingot, and measuring the content Cs of nitrogen elements at positions 5, 15, 25, 35 and 45mm away from the center by using a nitrogen-oxygen analyzer at the height of 1/2-3/4 of the high-nitrogen austenitic stainless steel ingot, wherein the macrosegregation ratio Sr of the nitrogen elements is CS/C0Wherein, C0The average concentration of the nitrogen element of the ingot; selecting the maximum Sr value as the maximum macrosegregation ratio Sr of nitrogenmax。
Preferably, the nitrogen diffusion coefficient DsCalculated by a DICTRA software module in Thermo-Calc software.
Preferably, the nitrogen solute distribution coefficient k is calculated by an equilibrium solidification model in Thermo-Calc software.
Preferably, the solidus temperature TSAnd liquidus temperature TLCalculated by an equilibrium solidification model in Thermo-Calc.
The invention also provides a method for preparing the high-nitrogen austenitic stainless steel by pressure induction, which comprises the following steps:
smelting a high-nitrogen austenitic stainless steel smelting raw material in a pressurized induction furnace, and then adding electrolytic aluminum for deoxidation to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to a target solidification pressure, and then pouring the smelting liquid into a cylindrical casting mold at a temperature of 1540-1580 ℃; after the pouring is finished, keeping for more than 20 minutes, and then gradually reducing the pressure in the furnace to obtain a high-nitrogen austenitic stainless steel ingot;
the target solidification pressure is the solidification pressure obtained by the acquisition method in the technical scheme.
The acquisition method of the invention refers to the component segregation, the nitrogen solubility and the cooling rate in the pressure induction smelting process, obtains the accurate solidification pressure, and can effectively solve the problems of nitrogen escape and nitrogen pore formation in the solidification process and improve the quality of the high-nitrogen austenitic stainless steel by utilizing the solidification pressure to prepare the high-nitrogen austenitic stainless steel.
Drawings
FIG. 1 is a photograph of a longitudinal section of a high nitrogen austenitic stainless steel obtained in example 1;
FIG. 2 is a photograph of a longitudinal section of the high nitrogen austenitic stainless steel obtained in example 2.
Detailed Description
The invention provides a method for acquiring solidification pressure required by preparing high-nitrogen austenitic stainless steel by pressure induction, which comprises the following steps of:
obtaining the cooling rate vcMaximum macrosegregation ratio of nitrogen SrmaxNitrogen diffusion coefficient DsNitrogen solute distribution coefficient k, solidus temperature TSAnd liquidus temperature TL；
Obtaining a nitrogen macrosegregation parameter M according to the formula (1)N；
Figure BDA0002843986080000041
Wherein [% N ] is the mass percentage of N element in the high-nitrogen austenitic stainless steel;
the activity of nitrogen element is obtained by the formula (2)
Figure BDA0002843986080000042
Figure BDA0002843986080000043
In the formula:
Figure BDA0002843986080000044
is the interaction coefficient of nitrogen element to nitrogen element;
Figure BDA0002843986080000045
is the first order interaction coefficient of element j to nitrogen element;
Figure BDA0002843986080000046
is the secondary interaction parameter of element j to nitrogen, [% j]The mass percentage of element j in the high-nitrogen austenitic stainless steel is shown;
obtaining the required solidification pressure P of the high-nitrogen austenitic stainless steel through a formula (3)S：
Figure BDA0002843986080000047
In the formula: pθIs at standard atmospheric pressure;
the high-nitrogen austenitic stainless steel comprises the following elements in percentage by mass:
c: less than or equal to 0.2 percent, Mn: 13-20%, Cr: 15-22%, Si: less than or equal to 1 percent, Mo: 0-4.5%, N: 0.7-2%, Ni: 0-4% and the balance Fe.
The invention obtains the cooling rate vcMaximum macrosegregation ratio of nitrogen SrmaxNitrogen diffusion coefficient DsNitrogen solute distribution coefficient k, solidus temperature TSAnd liquidus temperature TL；
Obtaining a nitrogen macrosegregation parameter M according to the formula (1)N；
Figure BDA0002843986080000051
Wherein [% N ] is the mass percentage of N element in the high-nitrogen austenitic stainless steel.
In the present invention, the nitrogen diffusion coefficient DsPreferably, the calculation is carried out by a DICTRA soft module in Thermo-Calc software, and specifically comprises the following steps: inputting the element composition of the high-nitrogen austenitic stainless steel into a DICTRA module to obtain a nitrogen diffusion coefficient Ds。
In the invention, the nitrogen solute distribution coefficient k is preferably calculated by a balanced solidification model in Thermo-Calc software, and specifically comprises the following steps: inputting the element composition of the high-nitrogen austenitic stainless steel into a Thermo-Clac software to balance a solidification model, and setting the reference pressure to be 0.1MPa to obtain a nitrogen solute distribution coefficient k.
In the present invention, the solidus temperature TSAnd liquidus temperature TLPreferably, the method is calculated by a balanced solidification model of Thermo-Calc software, and specifically comprises the following steps: inputting the element composition of the high-nitrogen austenite alloy into a balanced solidification model, and setting the reference pressure to be 0.1MPa to obtain the solidus temperature TSAnd liquidus temperature TL。
In the present invention, the obtaining of the cooling rate vcThe method comprises the following steps:
smelting raw materials with the same components as the high-nitrogen austenitic stainless steel are placed in a pressurized induction furnace for smelting, and then electrolytic aluminum is added to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to 0.8-1.2 MPa, and pouring the smelting solution into a cylindrical casting mold to obtain a high-nitrogen austenitic stainless steel ingot;
measuring the cooling rate during casting, i.e. the cooling rate vc。
In the present invention, the determination of the cooling rate during casting preferably comprises the steps of:
two through holes which vertically penetrate through the side wall of the casting mold are respectively drilled on the outer wall of the cylindrical casting mold at a height of 160mm from the bottom along the circumferential direction, the through holes are respectively a first through hole and a second through hole, the diameter of each through hole is 7mm independently, and the distance between the two through holes is 30mm according to the adjacent edges of the two holes on the outer wall of the casting mold; the first thermocouple and the second thermocouple are arranged in the first through hole and the second through hole, and the radial distances between the temperature points of the first thermocouple and the second thermocouple and the inner wall of the cylindrical casting mold are respectively 10mm and 15 mm;
recording the temperature variation of the molten liquid measured by the first thermocouple and the second thermocouple within a certain time in the solidification process, calculating to obtain a first cooling speed and a second cooling speed, and calculating the average value of the two cooling speeds as the cooling speed vc。
In the present invention, the maximum macrosegregation ratio Sr of the obtained nitrogenmaxThe method comprises the following steps:
and (3) longitudinally planing the high-nitrogen austenitic stainless steel ingot, and measuring the content Cs of nitrogen elements at positions 5, 15, 25, 35 and 45mm away from the center by using a nitrogen-oxygen analyzer at the height of 1/2-3/4 of the high-nitrogen austenitic stainless steel ingot, wherein the macrosegregation ratio Sr of the nitrogen elements is CS/C0Wherein, C0The average concentration of the nitrogen element of the ingot; selecting the maximum Sr value as the maximum macrosegregation ratio Sr of nitrogenmax。
The invention obtains the activity of nitrogen element by formula (2)
Figure BDA0002843986080000061
Figure BDA0002843986080000062
In the formula:
Figure BDA0002843986080000063
is nitrogen element to nitrogenThe elemental interaction coefficient;
Figure BDA0002843986080000064
is the first order interaction coefficient of element j to nitrogen element;
Figure BDA0002843986080000065
is the secondary interaction parameter of element j to nitrogen, [% j]Is the mass percentage content of the element j in the high-nitrogen austenitic stainless steel.
In the present invention, the
Figure BDA0002843986080000066
And
Figure BDA0002843986080000067
preferably by consulting a tool book on the basis of the elemental composition of the high nitrogen austenitic stainless steel.
The invention obtains the required solidification pressure P of the high-nitrogen austenitic stainless steel by the formula (3)S：
Figure BDA0002843986080000068
In the formula: pθIs at standard atmospheric pressure.
The invention also provides a method for preparing the high-nitrogen austenitic stainless steel by pressure induction, which comprises the following steps:
smelting a high-nitrogen austenitic stainless steel smelting raw material in a pressurized induction furnace, and then adding electrolytic aluminum for deoxidation to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to a target solidification pressure, and then pouring the smelting liquid into a cylindrical casting mold at a temperature of 1540-1580 ℃; after the pouring is finished, keeping for more than 20 minutes, and then gradually reducing the pressure in the furnace to obtain a high-nitrogen austenitic stainless steel ingot;
the target solidification pressure is the solidification pressure obtained by the acquisition method in the technical scheme.
In the invention, the smelting parameters are preferably consistent with the technical scheme, and are not described again.
The method for obtaining the solidification pressure required for preparing the high nitrogen austenitic stainless steel by pressure induction and the preparation method thereof provided by the present invention will be described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.
The main components of the raw materials for smelting used in examples 1 and 2 of the present invention are shown in Table 1.
TABLE 1 Main ingredient (wt%) of smelting raw material
Figure BDA0002843986080000071
Example 1
The target high-nitrogen austenitic stainless steel is 19Cr14Mn4Mo0.9N, and the component control range and smelting control target are shown in Table 2.
Table 219 Cr14Mn4Mo0.9N component control Range and control target (wt%)
Figure BDA0002843986080000072
The solidification pressure acquisition method comprises the following steps:
(1) according to the target component of the high-nitrogen austenitic stainless steel, calculating the nitrogen diffusion coefficient D in the solid phase by utilizing thermodynamic and kinetic calculation softwaresIs 2.4X 10-9The solute distribution coefficient k of nitrogen in the solidification process is 0.18, and the high-nitrogen austenitic stainless steel has a solid TS1594.18K, liquidus temperature TL1649.27K;
(2) maximum macrosegregation ratio Sr of nitrogenmaxAnd acquisition of cooling rate:
smelting raw materials with the same components as the high-nitrogen austenitic stainless steel are placed in a pressurized induction furnace for smelting, and then electrolytic aluminum is added to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to 0.8-1.2 MPa, and pouring the smelting solution into a cylindrical casting mold to obtain a high-nitrogen austenitic stainless steel ingot;
measuring the cooling rate during casting, i.e. the cooling rate vc。
The method for measuring the cooling speed in the pouring process comprises the following steps:
two through holes which vertically penetrate through the side wall of the casting mold are respectively drilled on the outer wall of the cylindrical casting mold at a height of 160mm from the bottom along the circumferential direction, the through holes are respectively a first through hole and a second through hole, the diameter of each through hole is 7mm independently, and the distance between the two through holes is 30mm according to the adjacent edges of the two holes on the outer wall of the casting mold; the first thermocouple and the second thermocouple are arranged in the first through hole and the second through hole, and the radial distances between the temperature points of the first thermocouple and the second thermocouple and the inner wall of the cylindrical casting mold are respectively 10mm and 15 mm;
recording temperature variation measured by a first thermocouple and a second thermocouple of the smelting liquid within 20min in the solidification process, calculating to obtain a first cooling speed and a second cooling speed, and calculating the average value of the two cooling speeds as the cooling speed vcIs 2K/s.
The maximum macrosegregation ratio Sr of the obtained nitrogenmaxThe method comprises the following steps:
and (3) longitudinally planing the high-nitrogen austenitic stainless steel ingot, and measuring the content Cs of nitrogen elements at positions 5, 15, 25, 35 and 45mm away from the center by using a nitrogen-oxygen analyzer at the height of 1/2-3/4 of the high-nitrogen austenitic stainless steel ingot, wherein the macrosegregation ratio Sr of the nitrogen elements is CS/C0Wherein, C0The average concentration of the nitrogen element of the ingot; selecting the maximum Sr value as the maximum macrosegregation ratio Sr of nitrogenmax1.25；
Calculating nitrogen macrosegregation parameter M by formula (1)N＝1.85；
(3) Determination of the activity of the nitrogen element: calculating the activity of nitrogen element according to the target composition of the steel grade and the nitrogen macrosegregation parameter by the formula (2):
Figure BDA0002843986080000081
(4) determination of the solidification pressure: calculating the required solidification pressure P when the high-nitrogen austenitic stainless steel is solidified through the formula (3)SNot less than 0.99MPa, namely the minimum solidification pressure is 0.99 MPa.
A method for preparing high-nitrogen austenitic stainless steel by pressure induction comprises the following steps:
smelting a high-nitrogen austenitic stainless steel smelting raw material in a pressurized induction furnace, and then adding electrolytic aluminum for deoxidation to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to 1.2MPa, and then pouring the smelting liquid into a cylindrical casting mold at 1540-1580 ℃; after the casting is finished, the casting is kept for more than 20 minutes, and then the pressure in the furnace is gradually reduced to obtain the high-nitrogen austenitic stainless steel ingot.
FIG. 1 is a photograph showing a longitudinal section of the high-nitrogen austenitic stainless steel obtained in this example, and it can be seen from FIG. 1 that the high-nitrogen austenitic stainless steel prepared at a solidification pressure of 1.2MPa has a dense structure without nitrogen pore defects.
The chemical compositions of the obtained high-nitrogen austenitic stainless steel are shown in Table 3
TABLE 3 chemical composition of the finished Steel (wt%)
Figure BDA0002843986080000082
Example 2
The target high-nitrogen austenitic stainless steel is 19Cr18Mn2Mo0.9N, and the component control range and smelting control target are shown in Table 4.
Table 419 Cr18Mn2Mo0.9N component control range and control target (wt%)
Figure BDA0002843986080000091
The solidification pressure acquisition method comprises the following steps:
(1) according to the target component of the high-nitrogen austenitic stainless steel, calculating the nitrogen diffusion coefficient D in the solid phase by utilizing thermodynamic and kinetic calculation softwaresIs 1.6X 10-9The solute distribution coefficient k of nitrogen in the solidification process is 0.18, and the high-nitrogen austenitic stainless steel has a solid TS1587.1K, liquidus temperature TL1630.7K.
(2) Maximum macrosegregation ratio Sr of nitrogenmaxAnd acquisition of cooling rate:
smelting raw materials with the same components as the high-nitrogen austenitic stainless steel are placed in an induction furnace for smelting, and then electrolytic aluminum is added to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to 0.8-1.2 MPa, and pouring the smelting solution into a cylindrical casting mold to obtain a high-nitrogen austenitic stainless steel ingot;
measuring the cooling rate during casting, i.e. the cooling rate vc。
The method for measuring the cooling speed in the pouring process comprises the following steps:
two through holes which vertically penetrate through the side wall of the casting mold are respectively drilled on the outer wall of the cylindrical casting mold at a height of 160mm from the bottom along the circumferential direction, the through holes are respectively a first through hole and a second through hole, the diameter of each through hole is 7mm independently, and the distance between the two through holes is 30mm according to the adjacent edges of the two holes on the outer wall of the casting mold; the first thermocouple and the second thermocouple are arranged in the first through hole and the second through hole, and the radial distances between the temperature points of the first thermocouple and the second thermocouple and the inner wall of the cylindrical casting mold are respectively 10mm and 15 mm;
recording temperature change amounts measured by a first thermocouple and a second thermocouple of the smelting liquid within 20min in the solidification process, calculating to obtain a first cooling speed and a second cooling speed, and calculating the average value of the two cooling speeds as the cooling speed vcIt was 1.5K/s.
The maximum macrosegregation ratio Sr of the obtained nitrogenmaxThe method comprises the following steps:
and (3) longitudinally planing the high-nitrogen austenitic stainless steel ingot, and measuring the content Cs of nitrogen elements at positions 5, 15, 25, 35 and 45mm away from the center by using a nitrogen-oxygen analyzer at the height of 1/2-3/4 of the high-nitrogen austenitic stainless steel ingot, wherein the macrosegregation ratio Sr of the nitrogen elements is CS/C0Wherein, C0To ingot nitrogenThe average concentration of the element; selecting the maximum Sr value as the maximum macrosegregation ratio Sr of nitrogenmaxIs 1.36;
calculating nitrogen macrosegregation parameter M by formula (1)N＝2.07。
(3) Determination of the activity of the nitrogen element: calculating the activity of nitrogen element according to the target composition of the steel grade and the nitrogen macrosegregation parameter by the formula (2):
Figure BDA0002843986080000101
(4) determination of the solidification pressure: calculating the required solidification pressure P when the high-nitrogen austenitic stainless steel is solidified through the formula (3)SNot less than 0.89MPa, namely the minimum solidification pressure is 0.89 MPa.
A method for preparing high-nitrogen austenitic stainless steel by pressure induction comprises the following steps:
smelting a high-nitrogen austenitic stainless steel smelting raw material in a pressurized induction furnace, and then adding electrolytic aluminum for deoxidation to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to 1.0MPa, and then pouring the smelting liquid into a cylindrical casting mold at 1540-1580 ℃; after the casting is finished, the casting is kept for more than 20 minutes, and then the pressure in the furnace is gradually reduced to obtain the high-nitrogen austenitic stainless steel ingot.
FIG. 2 is a photograph showing a longitudinal section of the high nitrogen austenitic stainless steel obtained in the present example, and it can be seen from FIG. 2 that: the ingot prepared under the solidification pressure of 1.0MPa has compact structure and no nitrogen pore defect.
The chemical composition of the obtained high nitrogen austenitic stainless steel is shown in table 5.
TABLE 5 chemical composition of the finished Steel (wt%)
Figure BDA0002843986080000102
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. The method for acquiring the solidification pressure required by the preparation of the high-nitrogen austenitic stainless steel by pressure induction is characterized by comprising the following steps of:
obtaining the cooling rate vcMaximum macrosegregation ratio of nitrogen SrmaxNitrogen diffusion coefficient DsNitrogen solute distribution coefficient k, solidus temperature TSAnd liquidus temperature TL；
Obtaining a nitrogen macrosegregation parameter M according to the formula (1)N；
Figure FDA0002843986070000011
Wherein [% N ] is the mass percentage of N element in the high-nitrogen austenitic stainless steel;
the activity of nitrogen element is obtained by the formula (2)
Figure FDA0002843986070000012
Figure FDA0002843986070000013
In the formula:
Figure FDA0002843986070000014
is the interaction coefficient of nitrogen element to nitrogen element;
Figure FDA0002843986070000015
is the first order interaction coefficient of element j to nitrogen element;
Figure FDA0002843986070000016
is the secondary interaction parameter of element j to nitrogen, [% j]Is highThe mass percentage of the element j in the nitrogen austenitic stainless steel;
obtaining the required solidification pressure P of the high-nitrogen austenitic stainless steel through a formula (3)S：
Figure FDA0002843986070000017
In the formula: pθIs at standard atmospheric pressure;
the high-nitrogen austenitic stainless steel comprises the following elements in percentage by mass:
c: less than or equal to 0.2 percent, Mn: 13-20%, Cr: 15-22%, Si: less than or equal to 1 percent, Mo: 0-4.5%, N: 0.7-2%, Ni: 0-4% and the balance Fe.
2. The method of claim 1, wherein said obtaining a cooling rate vcThe method comprises the following steps:
smelting raw materials with the same components as the high-nitrogen austenitic stainless steel are placed in a pressurized induction furnace for smelting, and then electrolytic aluminum is added to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to 0.8-1.2 MPa, and pouring the smelting solution into a cylindrical casting mold to obtain a high-nitrogen austenitic stainless steel ingot;
measuring the cooling rate during casting, i.e. the cooling rate vc。
3. The method of claim 2, wherein said determining a cooling rate during casting comprises the steps of:
two through holes which vertically penetrate through the side wall of the casting mold are respectively drilled on the outer wall of the cylindrical casting mold at a height of 160mm from the bottom along the circumferential direction, the through holes are respectively a first through hole and a second through hole, the diameter of each through hole is 7mm independently, and the distance between the two through holes is 30mm according to the adjacent edges of the two holes on the outer wall of the casting mold; the first thermocouple and the second thermocouple are arranged in the first through hole and the second through hole, and the radial distances between the temperature points of the first thermocouple and the second thermocouple and the inner wall of the cylindrical casting mold are respectively 10mm and 15 mm;
recording the temperature variation of the molten liquid measured by the first thermocouple and the second thermocouple within a certain time in the solidification process, calculating to obtain a first cooling speed and a second cooling speed, and calculating the average value of the two cooling speeds as the cooling speed vc。
4. The method of claim 2, wherein the maximum macrosegregation ratio Sr of the captured nitrogenmaxThe method comprises the following steps:
and (3) longitudinally planing the high-nitrogen austenitic stainless steel ingot, and measuring the content Cs of nitrogen elements at positions 5, 15, 25, 35 and 45mm away from the center by using a nitrogen-oxygen analyzer at the height of 1/2-3/4 of the high-nitrogen austenitic stainless steel ingot, wherein the macrosegregation ratio Sr of the nitrogen elements is CS/C0Wherein, C0The average concentration of the nitrogen element of the ingot; selecting the maximum Sr value as the maximum macrosegregation ratio Sr of nitrogenmax。
5. The acquisition method according to claim 1, characterised in that said nitrogen diffusion coefficient DsCalculated by a DICTRA software module in Thermo-Calc software.
6. The acquisition method according to claim 1, characterized in that the nitrogen solute distribution coefficient k is calculated by means of an equilibrium solidification model in Thermo-Calc software.
7. The acquisition method according to claim 1, characterized in that said solidus temperature T isSAnd liquidus temperature TLCalculated by an equilibrium solidification model in Thermo-Calc.
8. A method for preparing high-nitrogen austenitic stainless steel by pressure induction is characterized by comprising the following steps:
smelting a high-nitrogen austenitic stainless steel smelting raw material in a pressurized induction furnace, and then adding electrolytic aluminum for deoxidation to obtain a smelting solution; the dosage of the electrolytic aluminum is 1.0-2.0 kg/ton;
filling nitrogen into the pressurized induction furnace to a target solidification pressure, and then pouring the smelting liquid into a cylindrical casting mold at a temperature of 1540-1580 ℃; after the pouring is finished, keeping for more than 20 minutes, and then gradually reducing the pressure in the furnace to obtain a high-nitrogen austenitic stainless steel ingot;
the target solidification pressure is the solidification pressure obtained by the obtaining method of any one of claims 1 to 7.
CN202011502382.XA 2020-12-18 2020-12-18 Method for obtaining solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and preparation method Active CN112695151B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011502382.XA CN112695151B (en) 2020-12-18 2020-12-18 Method for obtaining solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and preparation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011502382.XA CN112695151B (en) 2020-12-18 2020-12-18 Method for obtaining solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and preparation method

Publications (2)

Publication Number Publication Date
CN112695151A true CN112695151A (en) 2021-04-23
CN112695151B CN112695151B (en) 2022-01-25

Family

ID=75508981

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011502382.XA Active CN112695151B (en) 2020-12-18 2020-12-18 Method for obtaining solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and preparation method

Country Status (1)

Country Link
CN (1) CN112695151B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116024398A (en) * 2023-02-24 2023-04-28 东北大学 Determination method for minimum value of solidification pressure for inhibiting nitrogen pores, application of determination method and preparation method of high-nitrogen stainless steel cast ingot

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5798625A (en) * 1980-12-06 1982-06-18 Aichi Steel Works Ltd Nonmagnetic stainless steel and its manufacture
CN101260478A (en) * 2008-04-17 2008-09-10 东北大学 Method for smelting high-nitrogen steel by compression electroslag furnace
CN104862609A (en) * 2015-03-13 2015-08-26 东北大学 Method for pressurized induction smelting of high nitrogen stainless steel through pressure control in stages
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
CN110026541A (en) * 2019-04-15 2019-07-19 中国兵器工业第五九研究所 The vacuum melting of ultra-thin-wall high-air-tightness Al-alloy parts, pressure changeable coagulation forming method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5798625A (en) * 1980-12-06 1982-06-18 Aichi Steel Works Ltd Nonmagnetic stainless steel and its manufacture
CN101260478A (en) * 2008-04-17 2008-09-10 东北大学 Method for smelting high-nitrogen steel by compression electroslag furnace
CN104862609A (en) * 2015-03-13 2015-08-26 东北大学 Method for pressurized induction smelting of high nitrogen stainless steel through pressure control in stages
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
CN110026541A (en) * 2019-04-15 2019-07-19 中国兵器工业第五九研究所 The vacuum melting of ultra-thin-wall high-air-tightness Al-alloy parts, pressure changeable coagulation forming method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116024398A (en) * 2023-02-24 2023-04-28 东北大学 Determination method for minimum value of solidification pressure for inhibiting nitrogen pores, application of determination method and preparation method of high-nitrogen stainless steel cast ingot
CN116024398B (en) * 2023-02-24 2024-08-09 东北大学 Determination method for minimum value of solidification pressure for inhibiting nitrogen pores, application of determination method and preparation method of high-nitrogen stainless steel cast ingot

Also Published As

Publication number Publication date
CN112695151B (en) 2022-01-25

Similar Documents

Publication Publication Date Title
CN103320711B (en) Weldless steel tube and manufacture method thereof
CN104109816B (en) Carburizing alloy steel, and preparation method and application thereof
US20100236670A1 (en) Heavy wall seamless steel pipe for line pipe and a manufacturing method thereof
CN103981445B (en) H13 hot-work die steel production technique
CN108517461B (en) High-performance martensitic stainless steel flange and manufacturing method thereof
CN103350202A (en) Method for manufacturing high-quality SCr420 HB automobile gear steel
CN112695151B (en) Method for obtaining solidification pressure required by preparing high-nitrogen austenitic stainless steel through pressure induction and preparation method
CN103205605A (en) High-temperature-oxidation-resistant casting nickel-based alloy and preparation method thereof
CN109371332A (en) A kind of 16MnCrS5 pinion steel and its production method
CN110643896A (en) Ultra-supercritical high-nitrogen martensite cast steel and preparation method thereof
CN104818426A (en) High-strength microalloyed rare-earth cast steel and preparation method thereof
CN104561829A (en) High-wear-resistant steel for railway frog and manufacturing method thereof
Zhu et al. Effect of pressure on dendrite structure and characteristics of carbides during solidification process of H13 die steel ingot
CN107574362A (en) A kind of antifriction alloy composite ring and its manufacture method, manufacture device
CN104451030A (en) Method for accurately controlling boron content during smelting of boron-containing steel in vacuum induction furnace
CN109355574A (en) A kind of cutter ring alloy of high abrasion high tenacity and preparation method thereof
CN102965589B (en) Mechanical expanding machine pull rod shaft with high fatigue strength and preparation method thereof
CN114635077A (en) Super austenitic stainless steel and preparation method thereof
RU2584315C1 (en) Structural cryogenic austenite high-strength corrosion-resistant, including bioactive media, welded steel and method of processing
CN112733465B (en) Method for acquiring solidification pressure required by pressurizing electroslag remelting high-nitrogen austenitic stainless steel and preparation method
CN109338204A (en) A kind of wear-resisting type cutter ring of disc cutter and preparation method thereof
RU2469117C1 (en) Melting method of carbon-free heat-resistant steel
CN103614631A (en) Rare earth-containing body of perforating gun and preparation method thereof
CN116024398B (en) Determination method for minimum value of solidification pressure for inhibiting nitrogen pores, application of determination method and preparation method of high-nitrogen stainless steel cast ingot
CN104894472B (en) Elevated oxygen level steel and its smelting process

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