CN114657450A - Hypereutectic ultrahigh-chromium cast iron material suitable for fine-particle industrial mines, preparation method and application thereof, and slurry pump overflowing piece - Google Patents
Hypereutectic ultrahigh-chromium cast iron material suitable for fine-particle industrial mines, preparation method and application thereof, and slurry pump overflowing piece Download PDFInfo
- Publication number
- CN114657450A CN114657450A CN202210273831.0A CN202210273831A CN114657450A CN 114657450 A CN114657450 A CN 114657450A CN 202210273831 A CN202210273831 A CN 202210273831A CN 114657450 A CN114657450 A CN 114657450A
- Authority
- CN
- China
- Prior art keywords
- hypereutectic
- cast iron
- chromium cast
- ultrahigh
- casting
- 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.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/06—Cast-iron alloys containing chromium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/02—Sand moulds or like moulds for shaped castings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
-
- 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
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/08—Manufacture of cast-iron
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/28—Normalising
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D5/00—Heat treatments of cast-iron
-
- 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
-
- 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
- C22C33/00—Making ferrous alloys
- C22C33/08—Making cast-iron alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/06—Cast-iron alloys containing chromium
- C22C37/08—Cast-iron alloys containing chromium with nickel
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/10—Cast-iron alloys containing aluminium or silicon
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/02—Selection of particular materials
- F04D29/026—Selection of particular materials especially adapted for liquid pumps
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/004—Dispersions; Precipitations
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- General Engineering & Computer Science (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
The invention provides a hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial and mining, a preparation method, application and a slurry pump overflowing piece, and relates to the field of high chromium cast iron; the material comprises the following chemical components in percentage by mass: 4.0-5.0 wt% of C, 0-1.0 wt% of Si, 1.5-2.5 wt% of Mn, 30-40 wt% of Cr, 0.5wt% of Mo max0.5wt%, 0.5wt% of Cu max0.5wt%, 0.5-1.0 wt% of Ni, 1.0wt% of V max1.0wt%, 0-0.08 wt% of Al, less than or equal to 0.03% of P, less than or equal to 0.025% of S, and the balance of Fe and inevitable impurities; when in preparation, molten steel is smelted firstly; then carrying out modification treatment in the discharging process, and casting tungsten carbide or chromium carbide particles along with the flow; casting into a casting and carrying out heat treatment to obtain the casting; the method disclosed by the invention has simple and convenient production process, and the prepared material can form higher carbide quantity due to higher carbon content and chromium content, so that the wear resistance of the material is greatly improved; when the material is applied to the preparation of the slurry pump overflowing piece, the material has excellent wear resistance, and the service life of the material is obviously prolonged.
Description
Technical Field
The invention relates to the technical field of high-chromium cast iron, in particular to a hypereutectic ultrahigh-chromium cast iron material suitable for fine-grained industrial and mining, a preparation method and application thereof, and a slurry pump overflowing piece.
Background
High-chromium cast iron is an excellent wear-resistant material and is widely applied to industrial production. A great deal of research finds that the wear resistance of the high-chromium cast iron can be obviously improved by improving the volume fraction of carbide in the high-chromium cast iron, and under the background, the development and application of hypereutectic high-chromium cast iron with higher carbon and chromium contents are paid attention. However, the hypereutectic high-chromium cast iron is extremely easy to crack in the casting and using processes due to the large quantity and the large brittleness of carbides, so that the popularization and the application of the hypereutectic high-chromium cast iron are limited.
At present, slurry pump products are widely applied to the industrial fields of mineral separation, electric power, sand production and the like, and the application conditions of the slurry pump products are harsh and complex. The abrasion factors of the overflowing part of the slurry pump are extremely complex, and on one hand, the overflowing part of the slurry pump is subjected to the actions of erosion abrasive abrasion, surface fatigue abrasion and corrosion abrasion; on the other hand, the slurry is affected by the size, shape, hardness of solid particles in the slurry, and the concentration, flow rate, corrosiveness and the like of the medium. In particular, high hardness materials, large particles, non-uniform shapes, and more severe wear. Therefore, the overflowing part fails early, the normal operation of the whole ore dressing system is seriously influenced, and huge loss is caused. Therefore, the method has important practical significance on how to prolong the service life of the slurry pump material.
At present, the flow passage components of domestic and foreign slurry pumps generally adopt BTMCr26And Cr15Mo3And the service life of the overflowing part is short due to insufficient wear resistance of the overflowing part in a mine with severe wear working conditions, which is a bottleneck restricting the development of slurry pumps in the industries. The wear resistance of the material for preparing the flow passage component is improved, and the method has important practical significance for prolonging the service life of the flow passage component and ensuring the running rate of a slurry pump.
Disclosure of Invention
The invention aims to provide a hypereutectic ultrahigh chromium cast iron material suitable for fine-particle industrial mines, a preparation method, application and a slurry pump overflowing piece, wherein the method adopts a special alterant to carry out modification treatment on molten iron in a ladle to refine primary and eutectic carbides, and heavy rare earth elements and the like in the special alterant are enriched on the surface of the primary carbides to refine and spheroidize the primary and eutectic carbides; during the casting process, particles such as tungsten carbide or chromium carbide and the like are added along with the flow to serve as cores for promoting nucleation of primary carbides, so that the nucleation number of the primary carbides is increased, and the solidification of the alloy is greatly accelerated; the prepared hypereutectic ultrahigh chromium cast iron material has good casting performance and excellent wear resistance.
In order to achieve the above purpose, the invention provides the following technical scheme: a hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines comprises the following chemical components in percentage by mass: 4.0-5.0 wt% of C, 0-1.0 wt% of Si, 1.5-2.5 wt% of Mn, 30-40 wt% of Cr, 0.5 wt% of Mo max0.5wt%, 0.5wt% of Cu max0.5wt%, 0-1.0 wt% of Ni, 1.0wt% of V max1.0wt%, 0-0.08 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities.
Further, the hypereutectic ultrahigh chromium cast iron material comprises the following chemical components in percentage by mass: 4.5 to 5.0 wt% of C, 0.3 to 0.8 wt% of Si, 1.5 to 2.0 wt% of Mn, 35 to 40 wt% of Cr, 0.1 to 0.3 wt% of Mo, 0.1 to 0.3 wt% of Cu, 0.5 to 1.0 wt% of Ni, 0.3 to 0.6 wt% of V, 0.03 to 0.06 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities.
Further, the hypereutectic ultrahigh chromium cast iron material comprises the following chemical components in percentage by mass: 4.8 wt% of C, 0.6 wt% of Si, 1.7 wt% of Mn, 36 wt% of Cr, 0.2 wt% of Mo, 0.2 wt% of Cu, 0.8 wt% of Ni, 0.3 wt% of V, 0.04 wt% of Al, less than or equal to 0.025 wt% of P, less than or equal to 0.02 wt% of S, and the balance of Fe and inevitable impurities.
Furthermore, the microstructure of the hypereutectic ultrahigh chromium cast iron material is a structure of a mixture of martensite, primary carbide, eutectic carbide, dispersed precipitated carbide and residual austenite, the hardness of the hypereutectic ultrahigh chromium cast iron material is 61-65 HRC, and the 10 × 55mm unnotched impact toughness is not lower than 2.5J/cm2。
The invention also discloses a preparation method of the hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines, which comprises the following steps of firstly, high-temperature smelting to obtain a material with the following components: 4.0-5.0 wt% of C, 0-1.0 wt% of Si, 1.5-2.5 wt% of Mn, 30-40 wt% of Cr, 0.5 wt% of Mo max0.5wt%, 0.5wt% of Cu max0.5wt%, 0-1.0 wt% of Ni, 1.0 wt% of Vmax1.0 wt%, 0-0.08 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities; then, modifying by using a modifier in the molten iron tapping process of the hypereutectic high-chromium cast iron, and simultaneously adding tungsten carbide particles or chromium carbide with the particle size of max0.5mm along with the molten iron flow during casting; finally, after the molten iron of the hypereutectic high-chromium cast iron is cast into a casting, the hypereutectic high-chromium cast iron material suitable for fine-grained industrial mines is obtained after the heat treatment by adopting the normalizing and low-temperature tempering processes.
Further, the preparation method specifically comprises the following steps:
(1) adding high-quality steel scrap, a low-sulfur recarburizing agent, high-carbon ferrochrome, low-carbon ferrochrome, ferrovanadium and high-carbon ferromanganese into an electric furnace, and heating and smelting to obtain molten iron of hypereutectic high-chromium cast iron;
(2) the smelting temperature is raised to 1480-1530 ℃, and the mixture is discharged and cast; wherein, a special YFB-C5 alterant is adopted for modification treatment in the tapping and casting process, and tungsten carbide or chromium carbide particles with the particle size of max0.5mm are added along with the molten iron flow during casting; the adding amount of the tungsten carbide and the chromium carbide particles is 0.3-0.5% and 0.2-0.3% of the weight of molten iron entering the casting ladle respectively;
(3) adopting a furan resin sand molding process, adopting baozhu sand as sand for molding, and adding furan resin and a curing agent; wherein the mass ratio of the Baozhu sand to the sand iron of the casting is 3-5: 1, the addition amount of furan resin is 1.1-1.2% of the mass of the Baozhu sand, and the addition amount of benzenesulfonic acid is 30-50% of the mass of the resin;
(4) casting the hypereutectic high-chromium cast iron by molten iron at 1380-1450 ℃ to obtain a casting;
(5) opening the casting, cooling to room temperature, and cleaning, including removing risers, flashes and flash;
(6) carrying out heat treatment on the casting in a heat treatment furnace, wherein the heat treatment comprises two procedures of normalizing and low-temperature tempering; wherein the normalizing process comprises the steps of preserving heat for 4-8 hours at 950-1050 ℃, and then taking out of the furnace and cooling to room temperature in air; the low-temperature tempering process comprises the steps of keeping the temperature of 200-250 ℃ for 4-8 hours, and then discharging from a furnace and air cooling to room temperature.
Further, the charging proportion of the materials in the step (1) is 27% of high-quality scrap steel, 58.6% of high-carbon ferrochrome, 10.3% of low-carbon ferrochrome, 2.5% of high-carbon ferromanganese, 0.33% of ferromolybdenum, 0.8% of nickel plate, 0.3% of ferrovanadium and the balance of low-sulfur carburant.
Further, the temperature control process of the casting heat treatment in the step (6) is as follows: when the temperature in the heat treatment furnace is less than 250 ℃, the heating speed is 20-40 ℃/h; when the temperature in the heat treatment furnace is 250-400 ℃, the heating rate is 10-30 ℃/h; when the temperature in the heat treatment furnace is 400-700 ℃, the heating rate is 40-60 ℃/h; when the temperature in the heat treatment furnace exceeds 700 ℃, the heating rate is 50-70 ℃/h.
The invention also discloses application of the hypereutectic ultrahigh chromium cast iron material suitable for fine-particle industrial and mining on the slurry pump overflowing piece.
The invention also provides a technical scheme and discloses the overflowing piece of the slurry pump, which is made of the hypereutectic ultrahigh chromium cast iron material suitable for fine-particle industrial mines.
According to the technical scheme, the technical scheme of the invention has the following beneficial effects:
the invention discloses a hypereutectic ultrahigh chromium cast iron material suitable for fine-particle industrial mines, a preparation method, application and a slurry pump overflowing piece, wherein the preparation method utilizes YFB-C5 special modifier and stream inoculant to refine primary and eutectic carbides, and converts a matrix structure into a microstructure of martensite, primary carbide, eutectic carbide, dispersed precipitated carbide and residual austenite blended by normalizing and low-temperature tempering processes; the prepared hypereutectic ultrahigh chromium cast iron material comprises the following chemical components in percentage by mass: 4.0-5.0 wt% of C, 0-1.0 wt% of Si, 1.5-2.5 wt% of Mn, 30-40 wt% of Cr, 0.5max wt% of Mo, 0.5max wt% of Cu, 0-1.0 wt% of Ni, 1.0max wt% of V, 0-0.08 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities; the hypereutectic high-chromium cast iron slurry pump overflowing piece produced by the method has the advantages of simple and convenient production process, low cost, good castability, excellent wear resistance and long service life.
Compared with the traditional BTMCr, the hypereutectic ultrahigh chromium cast iron material prepared by the invention26And Cr15Mo3The hypereutectic ultrahigh chromium cast iron material with the chemical component structure has higher carbon content and chromium content, can form higher carbide quantity, improves the volume fraction of the carbide, and can effectively improve the wear resistance of the material; the addition of Mo, Ni and Cu elements improves the hardenability of the materialThe special YFB-C5 modifier and the carbide stream inoculant refine primary and eutectic carbides; the normalizing and low-temperature tempering process strengthens the matrix structure of the hypereutectic ultrahigh chromium cast iron material and simultaneously ensures the mechanical property of the material.
It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be considered as part of the inventive subject matter of this disclosure unless such concepts are mutually inconsistent.
The foregoing and other aspects, embodiments and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. Additional aspects of the present invention, such as features and/or advantages of exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of specific embodiments in accordance with the teachings of the present invention.
Drawings
The figures are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a metallographic (100X) structure diagram of a hypereutectic ultra-high chromium cast iron material after final heat treatment in example 1 of the present invention;
FIG. 2 is a metallographic (500X) structure diagram of a hypereutectic ultra-high chromium cast iron material after final heat treatment in example 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without inventive step, are within the scope of protection of the invention. Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.
The use of "first," "second," and similar terms in the description and claims of the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Similarly, the singular forms "a," "an," or "the" do not denote a limitation of quantity, but rather denote the presence of at least one, unless the context clearly dictates otherwise. The terms "comprises," "comprising," or the like, mean that the elements or items listed before "comprises" or "comprising" encompass the features, integers, steps, operations, elements, and/or components listed after "comprising" or "comprising," and do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Based on BTMCr in the prior art26And Cr15Mo3The flow passage piece of the slurry pump made of materials and the like has the technical problems of insufficient wear resistance and short service life in the application process; the invention aims to provide a hypereutectic ultrahigh chromium cast iron material suitable for fine-particle industrial and mining, a preparation method, application and a slurry pump overflowing piece, the material greatly improves the volume fraction of carbide in the material by adding high carbon and high chromium, improves the wear resistance of the material, improves the hardenability of the material by adding Mo, Ni and Cu elements, and refines primary and eutectic carbide by using a special YFB-C5 modifier and a carbide stream inoculant; as the matrix structure of the hypereutectic ultrahigh chromium cast iron material is strengthened by adopting normalizing and low-temperature tempering processes during the preparation of the material, the mechanical property of the material is ensured, and the material has excellent wear resistance and long service life.
The invention discloses a hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial and mining, which comprises the following chemical components in percentage by mass: 4.0-5.0 wt% of C, 0-1.0 wt% of Si, 1.5-2.5 wt% of Mn, 30-40 wt% of Cr, 0.5 wt% of Mo max0.5wt%, 0.5wt% of Cu max0.5wt%, 0-1.0 wt% of Ni, 1.0wt% of V max1.0wt%, 0-0.08 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities.
When the hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines is prepared, firstly, the composition is obtained through high-temperature smelting: 4.0-5.0 wt% of C, 0-1.0 wt% of Si, 1.5-2.5 wt% of Mn, 30-40 wt% of Cr, 0.5 wt% of Mo max, 0.5 wt% of Cu max0.5wt%, 0-1.0 wt% of Ni, 1.0wt% of V max1.0wt%, 0-0.08 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities; then, modifying by using a modifier in the molten iron tapping process of the hypereutectic high-chromium cast iron, and simultaneously adding tungsten carbide particles or chromium carbide with the particle size of max0.5mm along with the molten iron flow during casting; finally, after the molten iron of the hypereutectic high-chromium cast iron is cast into a casting, the hypereutectic high-chromium cast iron material suitable for fine-grained industrial mines is obtained after the heat treatment by adopting the normalizing and low-temperature tempering processes.
When the preparation method is implemented, the preparation method specifically comprises the following steps:
(1) adding high-quality scrap steel, a low-sulfur recarburizing agent, high-carbon ferrochrome, low-carbon ferrochrome, ferromolybdenum, a nickel plate, ferrovanadium and high-carbon ferromanganese into an electric furnace, and heating and smelting according to the charging sequence of the high-quality scrap steel, the low-sulfur recarburizing agent, the high-carbon ferrochrome, the low-carbon ferrochrome, the ferromolybdenum, the nickel plate, the ferrovanadium and the high-carbon ferromanganese to obtain molten iron of hypereutectic high-chromium cast iron; wherein the charging proportion of each material is 27 percent of high-quality scrap steel, 58.6 percent of high-carbon ferrochromium, 10.3 percent of low-carbon ferrochromium, 2.5 percent of high-carbon ferromanganese, 0.33 percent of ferromolybdenum, 0.8 percent of nickel plate, 0.3 percent of ferrovanadium and the balance of low-sulfur carburant.
(2) The smelting temperature is raised to 1480-1530 ℃, and the mixture is discharged and cast; wherein, the special YFB-C5 alterant is adopted for modification treatment in the tapping and casting process, and tungsten carbide or chromium carbide particles with the particle size of max0.5mm are added along with the molten iron flow during casting; the adding amount of the tungsten carbide and the chromium carbide particles is 0.3-0.5% and 0.2-0.3% of the weight of molten iron entering the casting ladle respectively;
(3) adopting a furan resin sand molding process, adopting baozhu sand as sand for molding, and adding furan resin and a curing agent; wherein the mass ratio of the Baozhu sand to the sand iron of the casting is 3-5: 1, the addition amount of furan resin is 1.1-1.2% of the mass of the Baozhu sand, and the addition amount of benzenesulfonic acid is 30-50% of the mass of the resin;
(4) casting the hypereutectic high-chromium cast iron by molten iron at 1380-1450 ℃;
(5) cooling the casting to be lower than 200 ℃, opening the box, cooling to room temperature, and cleaning, wherein the cleaning comprises dead head, flash and flash removal;
(6) carrying out heat treatment on the casting in a heat treatment furnace, wherein the heat treatment comprises two procedures of normalizing and low-temperature tempering; wherein the normalizing process comprises the steps of preserving heat for 4-8 hours at 950-1050 ℃, and then taking out of the furnace and cooling to room temperature in air; the low-temperature tempering process comprises the steps of keeping the temperature of 200-250 ℃ for 4-8 hours, and then discharging from a furnace and air cooling to room temperature. The temperature rise rate is strictly controlled according to different stages in the heat treatment process, so that the problems of cracking and the like of the casting are avoided.
In order to improve the wear resistance of the prepared hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial and mining, the molten iron of the hypereutectic high chromium cast iron smelted in the step (1) can also comprise the following chemical components in percentage by mass: 4.5 to 5.0 wt% of C, 0.3 to 0.8 wt% of Si, 1.5 to 2.0 wt% of Mn, 35 to 40 wt% of Cr, 0.1 to 0.3 wt% of Mo, 0.1 to 0.3 wt% of Cu, 0.5 to 1.0 wt% of Ni, 0.3 to 0.6 wt% of V, 0.03 to 0.06 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025% of S, and the balance of Fe and inevitable impurities; the mass percentages of the chemical components are preferably as follows: 4.7 wt% of C, 0.6 wt% of Si, 1.8 wt% of Mn, 37 wt% of C, 0.25 wt% of Mo, 0.2 wt% of Cu, 0.7 wt% of Ni, 0.5 wt% of V, 0.04 wt% of Al, less than or equal to 0.025 wt% of P, less than or equal to 0.02% of S, and the balance of Fe and inevitable impurities.
The invention discloses a hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines and a preparation method thereof, which are further specifically described in the following with reference to specific embodiments. The following embodiments 1 to 3 are to apply the hypereutectic ultrahigh chromium cast iron material prepared by the method and suitable for fine-grained industrial mines to the preparation of slurry pump overflowing pieces, and to characterize the great improvement of the wear resistance of the material by carrying out wear resistance test on the slurry pump overflowing pieces.
Example 1
530 kg of high-quality scrap steel, 1173 kg of high-carbon ferrochromium, 205 kg of low-carbon ferrochromium, 52 kg of high-carbon ferromanganese, 7 kg of ferromolybdenum, 16 kg of nickel plate and 21 kg of ferrovanadium are sequentially added into a 2-ton intermediate frequency furnace for heating and melting, the molten steel is sampled and analyzed when reaching 1480 ℃, and the components are adjusted according to the detection result; after the components are qualified, heating and deoxidizing, and discharging at 1500 ℃. 6kg of special YFB-C5 alterant is added into the ladle before the ladle is taken out of the furnace. When the temperature in the ladle is measured to 1400 ℃, the casting is cast. Meanwhile, 4kg of carbide particles were flowed during casting.
Example 2
530 kg of high-quality scrap steel, 1110 kg of high-carbon ferrochromium, 260 kg of low-carbon ferrochromium, 52 kg of high-carbon ferromanganese, 7 kg of ferromolybdenum, 16 kg of nickel plate, 21 kg of ferrovanadium and 5kg of carburant are sequentially added into a 2-ton intermediate frequency furnace for heating and melting, the molten steel is sampled and analyzed when reaching 1500 ℃, and the components are adjusted according to the detection result. After the components are qualified, heating and deoxidizing, and discharging at 1510 ℃. 6kg of special YFB-C5 alterant is added into the ladle before the ladle is taken out of the furnace. When the temperature in the ladle was measured to 1390 ℃, the casting was removed. Meanwhile, 4kg of carbide particles were carried along during casting.
Example 3
Sequentially adding 520 kg of high-quality scrap steel, 935 kg of high-carbon ferrochrome, 425 kg of low-carbon ferrochrome, 52 kg of high-carbon ferromanganese, 7 kg of ferromolybdenum, 16 kg of nickel plates, 21 kg of ferrovanadium and 20kg of carburant into a 2-ton intermediate frequency furnace for heating and melting, sampling and analyzing molten steel when the molten steel reaches 1490 ℃, and adjusting components according to a detection result; after the components are qualified, heating and deoxidizing, and discharging from the furnace at 1520 ℃. 6kg of special YFB-C5 alterant is added into the ladle before the ladle is taken out of the furnace. When the temperature in the ladle was measured to 1420 ℃, the casting was removed. Meanwhile, 4kg of carbide particles were flowed during casting.
Opening the casting obtained in the embodiment 1-3 when the casting is cooled to below 200 ℃ in a sand box, wherein the opening is generally carried out 4-8 days after the casting; and continuously cooling to normal temperature, removing a dead head, a flash and a flash, and polishing. The polished casting is treated in a heat treatment furnace, and the treatment process comprises two procedures of normalizing and low-temperature tempering; the normalizing process comprises the steps of preserving heat for 4-8 hours at 950-1050 ℃, and then naturally cooling to room temperature; the low-temperature tempering process is to keep the temperature at 200-250 ℃ for 4-8 h, and then the product is discharged from the furnace and cooled to room temperature by air; the temperature rise rate is strictly controlled according to different stages in the heat treatment process, so that the problems of cracking and the like of the casting are avoided. When the temperature in the heat treatment furnace is less than 250 ℃, controlling the temperature rise speed to be 20-40 ℃/h; when the temperature in the heat treatment furnace is 250-400 ℃, the heating rate is controlled to be 10-30 ℃/h; when the temperature in the heat treatment furnace is 400-700 ℃, the heating rate is controlled to be 40-60 ℃/h; when the temperature in the heat treatment furnace exceeds 700 ℃, the heating rate is controlled to be 50-70 ℃/h.
Examples 1-3 above produced slurry pump flow-through pieces comprised of the above-described hypereutectic ultra high chromium cast iron material suitable for use in fine grained industrial mines, and the results of the chemical composition and hardness values of each slurry pump flow-through piece are shown in table 1.
Table 1 chemical composition and hardness values of flow pieces of slurry pump flow pieces manufactured in examples
The metallographic structure of the slurry pump overflowing piece prepared in the embodiment 1-3 is shown in attached figures 1 and 2; the microstructure of the slurry pump overflowing piece is martensite, primary carbide, eutectic carbide, dispersed precipitated carbide and residual austenite; specifically, the hypereutectic ultrahigh chromium cast iron material for manufacturing the slurry pump overflowing piece is subjected to performance test, the hardness is 61-65 HRC, and the 10 55mm unnotched impact toughness is not lower than 2.5J/cm2。
Slurry erosion and abrasion tests were performed on the slurry pump overflowing pieces prepared in examples 1 to 3 on an erosion and abrasion testing machine, and slurry was sampled from the mine. BTMCr commonly used as material of flow passage member26For comparison, the rotation speed was 1450 r/min. The material state is selected from a heat treatment state, and the wear resistance comparison result is shown in table 2:
TABLE 2 wear Performance comparison
The overflowing piece of the slurry pump prepared in the embodiment 1 is installed and applied, namely applied to a 200NZJC slurry pump of a certain mine; the original manufacturer adopts BTMCr26The overflowing piece has the service life of about 430h, and the overflowing piece of the slurry pump in the embodiment 1 has the service life of 800h, so that the wear resistance is improved by 80%.
The hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines has the excellent performances of high hardness, high carbide content, high wear resistance, high specific price and the like, and is an ideal material for a slurry pump overflowing piece when applied to the slurry pump overflowing piece; the application of the overflow piece of the slurry pump for fine-grained industrial and mining has important profound influence on prolonging the service life of the overflow piece of the slurry pump, ensuring the running rate of the slurry pump and improving the working efficiency.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.
Claims (10)
1. The hypereutectic ultrahigh chromium cast iron material is suitable for fine-grained industrial mines and is characterized by comprising the following chemical components in percentage by mass: 4.0-5.0 wt% of C, 0-1.0 wt% of Si, 1.5-2.5 wt% of Mn, 30-40 wt% of Cr, 0.5 wt% of Mo max, 0.5 wt% of Cu max0.5wt%, 0-1.0 wt% of Ni, 1.0wt% of V max1.08 wt%, 0-0.08 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities.
2. The hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines according to claim 1, wherein the composition of the hypereutectic ultrahigh chromium cast iron material comprises the following chemical components in percentage by mass: 4.5 to 5.0 wt% of C, 0.3 to 0.8 wt% of Si, 1.5 to 2.0 wt% of Mn, 35 to 40 wt% of Cr, 0.1 to 0.3 wt% of Mo, 0.1 to 0.3 wt% of Cu, 0.5 to 1.0 wt% of Ni, 0.3 to 0.6 wt% of V, 0.03 to 0.06 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities.
3. The hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines according to claim 1, wherein the composition of the hypereutectic ultrahigh chromium cast iron material comprises the following chemical components in percentage by mass: 4.8 percent of C, 0.6 percent of Si, 1.7 percent of Mn, 36 percent of Cr, 0.2 percent of Mo, 0.2 percent of Cu, 0.8 percent of Ni0.8 percent of V, 0.3 percent of Al, less than or equal to 0.025 percent of P, less than or equal to 0.02 percent of S, and the balance of Fe and inevitable impurities.
4. The hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines according to claim 1, wherein the microstructure of the hypereutectic ultrahigh chromium cast iron material is a structure of a mixture of martensite, primary carbides, eutectic carbides, dispersed precipitated carbides and retained austenite, the hardness of the hypereutectic ultrahigh chromium cast iron material is 61-65 HRC, and the unnotched impact toughness of 10 x 55mm is not lower than 2.5J/cm2。
5. A preparation method of hypereutectic ultrahigh chromium cast iron material suitable for fine-grained industrial mines according to any one of claims 1 to 4, characterized by firstly obtaining the following composition through high-temperature smelting: 4.0-5.0 wt% of C, 0-1.0 wt% of Si, 1.5-2.5 wt% of Mn, 30-40 wt% of Cr, 0.5 wt% of Mo max, 0.5 wt% of Cu max0.5wt%, 0-1.0 wt% of Ni, 1.0 wt% of V max, 0-0.08 wt% of Al, less than or equal to 0.03 wt% of P, less than or equal to 0.025 wt% of S, and the balance of Fe and inevitable impurities; then, modifying by using a modifier in the molten iron tapping process of the hypereutectic high-chromium cast iron, and simultaneously adding tungsten carbide particles or chromium carbide with the particle size of max0.5mm along with the molten iron flow during casting; finally, after the molten iron of the hypereutectic high-chromium cast iron is cast into a casting, the hypereutectic high-chromium cast iron material suitable for fine-grained industrial mines is obtained after the heat treatment by adopting the normalizing and low-temperature tempering processes.
6. The preparation method of the hypereutectic ultrahigh chromium cast iron material suitable for the fine-grained industrial mines according to claim 5, which comprises the following steps:
(1) adding high-quality steel scrap, a low-sulfur recarburizing agent, high-carbon ferrochrome, low-carbon ferrochrome, ferromolybdenum, a nickel plate, ferrovanadium and high-carbon ferromanganese into an electric furnace, and heating and smelting to obtain molten iron of hypereutectic high-chromium cast iron;
(2) the melting temperature is raised to 1480-1530 ℃, and the mixture is discharged and cast; wherein, the special YFB-C5 alterant is adopted for modification treatment in the tapping and casting process, and tungsten carbide or chromium carbide particles with the particle size of max0.5mm are added along with the molten iron flow during casting; the adding amount of the tungsten carbide and the chromium carbide particles is 0.3-0.5% and 0.2-0.3% of the weight of molten iron entering the casting ladle respectively;
(3) adopting a furan resin sand molding process, adopting baozhu sand as sand for molding, and adding furan resin and a curing agent; wherein the mass ratio of the gem and the casting is 3-5: 1, the addition of furan resin is 1.1-1.2% of the mass of the gem and the mass of the curing agent is 30-50% of the mass of the resin;
(4) casting the hypereutectic high-chromium cast iron by molten iron at 1380-1450 ℃;
(5) opening the casting, cooling to room temperature, and cleaning, including removing risers, flashes and flash;
(6) carrying out heat treatment on the casting in a heat treatment furnace, wherein the heat treatment comprises two procedures of normalizing and low-temperature tempering; wherein the normalizing process comprises the steps of preserving heat for 4-8 hours at 950-1050 ℃, and then taking out of a furnace and cooling the furnace to room temperature by air; the low-temperature tempering process comprises the steps of keeping the temperature of 200-250 ℃ for 4-8 hours, and then discharging from a furnace and air cooling to room temperature.
7. The method for preparing the hypereutectic ultrahigh chromium cast iron material suitable for the fine-grained industrial mines according to claim 6, wherein the feeding proportion of the materials in the step (1) is 27% of high-quality scrap steel, 58.6% of high-carbon ferrochrome, 10.3% of low-carbon ferrochrome, 2.5% of high-carbon ferromanganese, 0.33% of ferromolybdenum, 0.8% of nickel plate, 0.3% of ferrovanadium and the balance of low-sulfur carburant.
8. The preparation method of the hypereutectic ultrahigh chromium cast iron material suitable for the fine-grained industrial mines according to claim 6, wherein the temperature control process of the casting heat treatment in the step (6) is as follows: when the temperature in the heat treatment furnace is less than 250 ℃, the heating speed is 20-40 ℃/h; when the temperature in the heat treatment furnace is 250-400 ℃, the heating rate is 10-30 ℃/h; when the temperature in the heat treatment furnace is 400-700 ℃, the heating rate is 40-60 ℃/h; when the temperature in the heat treatment furnace exceeds 700 ℃, the heating rate is 50-70 ℃/h.
9. The use of the hypereutectic ultra-high chromium cast iron material for fine-grained industrial mines as defined in any one of claims 1 to 4 in the flow piece of a slurry pump.
10. The slurry pump overflowing piece is characterized in that the overflowing piece for the slurry pump is made of the hypereutectic ultrahigh chromium cast iron material suitable for fine-particle industrial mines according to any one of claims 1 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210273831.0A CN114657450A (en) | 2022-03-19 | 2022-03-19 | Hypereutectic ultrahigh-chromium cast iron material suitable for fine-particle industrial mines, preparation method and application thereof, and slurry pump overflowing piece |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210273831.0A CN114657450A (en) | 2022-03-19 | 2022-03-19 | Hypereutectic ultrahigh-chromium cast iron material suitable for fine-particle industrial mines, preparation method and application thereof, and slurry pump overflowing piece |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114657450A true CN114657450A (en) | 2022-06-24 |
Family
ID=82031522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210273831.0A Pending CN114657450A (en) | 2022-03-19 | 2022-03-19 | Hypereutectic ultrahigh-chromium cast iron material suitable for fine-particle industrial mines, preparation method and application thereof, and slurry pump overflowing piece |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114657450A (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1769508A (en) * | 2005-11-10 | 2006-05-10 | 西安交通大学 | Low cost, high-wearability hypereutectic high chromium cast iron and its production method |
| CN101302597A (en) * | 2008-06-05 | 2008-11-12 | 西安交通大学 | Hypereutectic high-chromium white cast iron and preparation thereof |
| CN101392349A (en) * | 2008-11-03 | 2009-03-25 | 河南科技大学 | Super high chromium wear and corrosion resistant cast iron and preparation technology thereof |
| CN102851570A (en) * | 2012-03-14 | 2013-01-02 | 宁波市圣盾机械制造有限公司 | High-carbon high-chromium refining plate casting of defibrator |
| CN102925783A (en) * | 2012-10-09 | 2013-02-13 | 西安交通大学 | Method for preparing hypereutectic high chromium white cast iron |
| CN104651705A (en) * | 2015-02-12 | 2015-05-27 | 北京工业大学 | Wear-resisting hypereutectic high-chromium cast iron and preparation method thereof |
| CN106591689A (en) * | 2016-11-15 | 2017-04-26 | 营口龙辰矿山车辆制造有限公司 | Hypereutectic high-chromium alloy white cast iron chute lining plate and preparation method thereof |
| CN106609334A (en) * | 2017-03-16 | 2017-05-03 | 石家庄铁道大学 | Ultra-high chromium cast iron and preparation method |
| CN107541642A (en) * | 2016-06-27 | 2018-01-05 | 鲍凡凡 | A kind of hypereutectic white iron and its manufacture method |
| CN113025874A (en) * | 2021-03-29 | 2021-06-25 | 北京工业大学 | Hypereutectic high-chromium cast iron and inoculation modification treatment method thereof |
-
2022
- 2022-03-19 CN CN202210273831.0A patent/CN114657450A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1769508A (en) * | 2005-11-10 | 2006-05-10 | 西安交通大学 | Low cost, high-wearability hypereutectic high chromium cast iron and its production method |
| CN101302597A (en) * | 2008-06-05 | 2008-11-12 | 西安交通大学 | Hypereutectic high-chromium white cast iron and preparation thereof |
| CN101392349A (en) * | 2008-11-03 | 2009-03-25 | 河南科技大学 | Super high chromium wear and corrosion resistant cast iron and preparation technology thereof |
| CN102851570A (en) * | 2012-03-14 | 2013-01-02 | 宁波市圣盾机械制造有限公司 | High-carbon high-chromium refining plate casting of defibrator |
| CN102925783A (en) * | 2012-10-09 | 2013-02-13 | 西安交通大学 | Method for preparing hypereutectic high chromium white cast iron |
| CN104651705A (en) * | 2015-02-12 | 2015-05-27 | 北京工业大学 | Wear-resisting hypereutectic high-chromium cast iron and preparation method thereof |
| CN107541642A (en) * | 2016-06-27 | 2018-01-05 | 鲍凡凡 | A kind of hypereutectic white iron and its manufacture method |
| CN106591689A (en) * | 2016-11-15 | 2017-04-26 | 营口龙辰矿山车辆制造有限公司 | Hypereutectic high-chromium alloy white cast iron chute lining plate and preparation method thereof |
| CN106609334A (en) * | 2017-03-16 | 2017-05-03 | 石家庄铁道大学 | Ultra-high chromium cast iron and preparation method |
| CN113025874A (en) * | 2021-03-29 | 2021-06-25 | 北京工业大学 | Hypereutectic high-chromium cast iron and inoculation modification treatment method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113235005B (en) | Cast bainite steel for semi-autogenous mill, preparation method thereof and cast bainite steel lining plate for semi-autogenous mill | |
| CN110079725B (en) | Ultra-high wear-resistant hypereutectic high-chromium cast iron material, and preparation method and application thereof | |
| CN103320720A (en) | Vanadium-containing high-boron high-chromium wear-resistant alloy and preparation method thereof | |
| CN113025874B (en) | Hypereutectic high-chromium cast iron and inoculation modification treatment method thereof | |
| CN112575261B (en) | Composite modified martensitic alloy cast steel | |
| CN111286681A (en) | High-wear-resistance low-cost steel for forging wet grinding balls and preparation method thereof | |
| CN112553521A (en) | Ductile iron bearing seat and preparation method thereof | |
| CN102230123A (en) | Chromium-based modified wear-resistant cast iron and preparation method thereof | |
| CN111378909A (en) | High-toughness high manganese steel lining plate and production process thereof | |
| CN116426827A (en) | Cast complex phase steel material suitable for lining plate of semi-autogenous mill and preparation method thereof | |
| CN114657450A (en) | Hypereutectic ultrahigh-chromium cast iron material suitable for fine-particle industrial mines, preparation method and application thereof, and slurry pump overflowing piece | |
| CN111250666A (en) | Pump case pouring process | |
| CN115261713B (en) | Preparation method of high-hardness high-toughness wear-resistant high-chromium cast iron | |
| CN107841688A (en) | A kind of method of the wear-resisting disintegrating machine cheek plate of lost foam casting medium managese steel | |
| CN112680661B (en) | Alloy steel and preparation method thereof | |
| CN114231851A (en) | Nano carbide reinforced wear-resistant steel and preparation method and application thereof | |
| CN105039833B (en) | Ferrovanadium chromium antifriction alloy and preparation method thereof | |
| CN113337776A (en) | High-wear-resistance high-chromium white cast iron for pump and preparation method thereof | |
| CN113265580A (en) | High-nitrogen high-vanadium high-chromium wear-resistant alloy and preparation method thereof | |
| CN116179932A (en) | Ultrahigh-carbon ultrahigh-chromium cast iron material for industrial and mining use and preparation method thereof | |
| CN111690867B (en) | Alloy cast iron and preparation method thereof | |
| CN1026251C (en) | Medium silicon wear-resistant manganese steel | |
| CN113736947B (en) | Preparation method of nodular cast iron | |
| CN114032474B (en) | Wear-resistant alloy steel and preparation method thereof | |
| CN116516256A (en) | Rare earth modified V-Cr-Mn iron-based wear-resistant alloy material and preparation method thereof |
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 | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20220624 |
|
| RJ01 | Rejection of invention patent application after publication |