CN109972050B

CN109972050B - Yttrium toughened wear-resistant alloy and casting and heat treatment method thereof

Info

Publication number: CN109972050B
Application number: CN201910403263.XA
Authority: CN
Inventors: 罗丰华; 牟楠; 唐紫薇; 付晓虎; 卢静; 陈亨
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2018-06-08
Filing date: 2019-05-15
Publication date: 2022-01-28
Anticipated expiration: 2039-05-15
Also published as: CN109972050A

Abstract

An yttrium toughened wear-resistant alloy and a casting and heat treatment method thereof are disclosed, wherein the mass percentage of each element of the alloy is Cr: 9.0-13.0, B: 2.6-2.9, C:0.7 to 0.9, Nb: 0.4-0.8, V: 0.4-0.8, Mn content less than 0.3, Y:0.02 to 1.6, S, P: less than or equal to 0.01, and the balance being Fe. Where C, B sums: 3.3 to 3.6; C/Cr mass ratio: 0.06 to 0.08; the sum of Nb and V is 0.5 to 1.0. First prepare Fe-Y₂O₃And pressing Fe-yttrium carbonate or Fe-yttrium nitrate powder into a block, mixing, smelting and modifying the alloy, casting the alloy, and then quenching and tempering, wherein the casting temperature is 1250-1320 ℃. The cast ingot has the integral hardness of HRC 65.4-69.4 and the impact toughness of 12.6-17.1J/cm²The bending strength reaches 1340-1750 MPa.

Description

Yttrium toughened wear-resistant alloy and casting and heat treatment method thereof

Technical Field

The invention belongs to the field of high-hardness wear-resistant cast iron, and relates to an alloy of yttrium modified fine hard phase, supersaturated solid solution and martensite matrix phase wear-resistant corrosion-resistant cast iron and a preparation method of a component thereof, which can be widely used for manufacturing mechanical wear-resistant parts in the industries of electric power, metallurgy, machinery, chemical industry and the like.

Technical Field

Fe-Cr-B-C wear-resistant casting alloy mainly containing Fe₂B or M₂B is a hard phase, has good toughness, high hardness, high corrosion resistance and good smelting-casting manufacturability. Modification treatment is one of effective methods for improving the texture and mechanical properties of Fe-Cr-B-C alloy. The modificator can be classified into strong carbon, nitrogen, sulfide-forming elements such as Ti, V, etc., and strong undercooling elements such as surface active elements Rare Earth (RE), Mg, etc., according to their effects.

The rare earth elements are gathered on a liquid-solid growth interface to limit the growth of crystal grains so as to improve the hardness, strength and wear resistance of the alloy; and the structure is refined, so that the boride is in broken net shape and granular distribution, and the impact toughness is improved. The research shows that: the addition of 0.6% cerium (Ce) to the Fe-Cr-B-C alloy improves the impact toughness by 86.4%. Adding 1.0% (Ce + La) of mixed alterant into Fe-Cr-B alloy, the hardness of the alloy is increased from 52HRC to 70.2HRC, and the impact toughness is increased from 3.36J/cm²Increased to 6.38J/cm²。

The rare earth modification can be a single modification method of rare earth alloy or rare earth wire, or composite modification treatment can be adopted, namely a mixture of elements such as N, Ti, V, Mg, Si and the like and rare earth is used as a modifier. The silicon-magnesium mixed rare earth alterant is most commonly a composite modification method, and researches show that: after the Fe-Cr-B-C alloy is modified by RE-Si-Mg, the impact toughness is improved by 72.2 percent compared with that before modification; after RE-Ti modification and heat treatment, the impact toughness is improved by 1.8 times; by RE-Mg deterioration impactThe toughness is improved by 34.6 percent; after the RE-Ti-N is modified, the net structure is completely disappeared, and the toughness is improved by 133.3%; after RE-Mg-V-Ti modification treatment, the impact toughness reaches 15.6J/cm²(ii) a After RE-Ti-Si-V modification treatment, the impact toughness reaches 12J/cm²The above.

These methods using rare earth modification all have a common difficulty, namely high activity pure rare earth, rare earth alloy or composite rare earth materials. Due to the high activity of the rare earth, the structure and the performance of the alterant or the alloy after the alteration treatment are difficult to control, and the alteration effect is difficult to ensure.

Document 1: LM cathode study-emission principle and present study [ D ]]Beijing university of industry, 2001: pp 44-50. Carbonized La₂O₃Chemical equilibrium of Mo alloy:

3Mo₂C(s)+La₂O₃(s)＝2La(s,l)+3CO(g)+6Mo

due to Mo₂C has much smaller change of free enthalpy of reduction reaction for generating the simple substance La, so that the equilibrium partial pressure of La and CO of reaction products is also 10 orders of magnitude higher. When the temperature is higher than 1673K, namely 1400 ℃, and the CO partial pressure is lower than E-9atm, the reaction formula automatically proceeds to the right, namely, the simple substance La is generated by reduction.

Patent document 2: the prepared wear-resistant alloy has the authorized bulletin number CN 105695884B, the hardness of HRC 66-70 and the impact toughness of 4-9J/cm². The alloy has high hardness, but insufficient impact toughness, low strength index and low bending strength within the range of 346-477 MPa, and limits the application of the alloy to occasions with large external load and impact resistance.

Document 3: the rapid cooling structure and performance of the eutectic Fe-Cr-B-C alloy are cast, wherein 2017, 66(10) are 1053-1056. The fast cooling structure of the cast Fe-Cr-B-C alloy consists of a martensite + retained austenite matrix and (Fe, Cr) continuously distributed in a net shape along grain boundaries₂(B,C)+(Fe,Cr)₂₃(B,C)₆A hard phase. The microhardness of the matrix phase of the rapid cooling structure is 800-880 HV, the microhardness of the hard phase is 1150-1400 HV, the macroscopic hardness is HRC68, and the impact toughness reaches 13.6J/cm²(ii) a And after annealing at 960 ℃ for 2h, the matrix structure is converted into ferriteGranular cementite, hard phase (Fe, Cr)₂(B, C) and (Fe, Cr)₂₃(B,C)₆A little dissolution, the network breaking and new phase (Fe, Cr) in local area₃(B, C), the microhardness of the matrix phase after annealing is 330-400 HV, the hard phase is 850-1250 HV, the macroscopic hardness is reduced to HRC46, and the impact toughness is reduced to 3.4J/cm². The results obtained in document 3 reflect that the hardness of the matrix phase plays a large role in the hardness and impact toughness of such materials; the alloy has the possibility of improving the solid solubility and hardness of a matrix phase by adopting high-temperature solution quenching-low-temperature tempering treatment, and the alloy has the possibility of improving the properties such as impact toughness and the like after heat treatment according to patent document 2.

Disclosure of Invention

The invention aims to provide an yttrium toughened wear-resistant alloy and a casting and heat treatment method thereof. The method employs yttrium oxide (Y)₂O₃) Yttrium nitrate or yttrium carbonate is used as a modifier, carbides and borides in the Fe-Cr-B-C alloy in a high-temperature melting state have thermodynamic conditions for promoting the formation of high-activity Y elements, and Y-containing compounds are formed at C, B, so that the structure of the cast alloy is refined, and the carborides are in a broken net shape and are in granular distribution; after heat treatment, the matrix is nonequilibrium phase such as high-hardness multi-element supersaturated solid solution, martensite, and the like, so that the alloy has good toughness, high hardness and higher strength index.

Due to Y₂O₃Or yttrium nitrate or yttrium carbonate has low density, and the Y element loss caused by floating up along with slag when the yttrium nitrate or yttrium carbonate is directly added into the melt, thereby losing the modification effect, therefore, the Y is adopted in the invention₂O₃And yttrium nitrate or yttrium carbonate powder and iron powder are uniformly mixed, and then are molded into powder pressing blocks, and then are melted together with the Fe-Cr-B-C casting alloy. Y is₂O₃The mass ratio of the yttrium nitrate powder to the iron powder is 1: 4-20, and a mixed briquette of Fe-3.75-15.77 wt.% Y is formed, or the mass ratio of the yttrium nitrate powder to the iron powder is 1: 3-9, and a mixed briquette of Fe-2.32-5.80% Y is formed, or the mass ratio of the yttrium carbonate powder to the iron powder is 1: 3-13, and a mixed briquette of Fe-3.09-10.8 wt.% Y is formed.

Too low Y content will result in too high Fe content and affect the batchingCalculating; when the Y content is too high, green compact formation is difficult. Wherein Y is₂O₃The powder is white amorphous powder with the content of more than 99.0 percent, or yttrium nitrate is a hydrated compound, the content of yttrium nitrate is more than 99.0 percent after drying and dehydration treatment before batching, or yttrium carbonate is a hydrated compound, and the content of yttrium nitrate is more than 99.0 percent after drying and dehydration treatment before batching. The Fe powder is reduced Fe powder or water atomized Fe powder, and the Fe powder can contain alloy elements in the modified cast iron or elements in the impurity range, such as Ni, V, Cr and the like, so as to be subject to the conditions of not influencing briquetting and influencing the batching calculation.

The invention selects the Fe-Cr-B-C alloy with high wear resistance and high corrosion resistance of the patent document 2 as a basic alloy, and then 0.02-1.6% of Y element is added for modification. Forming a multi-element eutectic alloy containing Fe, Cr, B, C, Nb, V, Y and other elements, wherein the mass percentage of each element is Cr: 9.0-13.0, B: 2.6-2.9, C:0.7 to 0.9, Nb: 0.4-0.8, V: 0.4-0.8, Mn content less than 0.3, Y:0.02 to 1.6, S, P: less than or equal to 0.01, and the balance being Fe. Where C, B sums: 3.3 to 3.6; C/Cr content ratio: 0.06 to 0.08; the sum of Nb and V is 0.5 to 1.0.

In patent document 2, for the specific preparation of an alloy, ferrochrome (high carbon, medium carbon, and micro carbon), ferroboron, ferroniobium, ferrovanadium, pure iron, and the like can be used in accordance with the component requirements. The raw materials and their components are listed in table 1.

TABLE 1 raw materials and compositions applicable to the preparation of the alloys of the invention

The raw material components of table 1 are not exclusive, and the specific components are determined by the raw materials that are actually available. Where ferrochrome, metallic chromium, ferroboron, ferroniobium and ferrovanadium provide the Cr, B, Nb and V content of the inventive alloy, high carbon ferrochrome is used to balance the C content. The pure iron comprises electrician pure iron, electromagnetic pure iron or industrial pure iron.

The method specifically comprises the following steps:

(1) y element carrier-powder compact preparation

Fe-Y₂O₃Powder briquetting: using iron powder and Y₂O₃After the powders are mixed evenly, the mixture is pressed into powder briquettes. Y is₂O₃The mass ratio of the powder to the iron powder is 1: 4-20, and Fe-Y of Fe-3.75-15.77 wt.% Y is formed₂O₃Mixed briquettes, or Fe-yttrium nitrate powder briquettes: iron powder and yttrium nitrate powder are uniformly mixed and molded into powder compacts. The mass ratio of the yttrium nitrate powder to the iron powder is 1: 3-9, and Fe-yttrium nitrate mixed briquettes with Fe-2.32-5.80% of Y are formed.

Or Fe-yttrium carbonate powder briquettes: iron powder and yttrium carbonate powder are uniformly mixed and molded into powder compacts. The mass ratio of the yttrium carbonate powder to the iron powder is 1: 3-13, and Fe-yttrium carbonate mixed briquettes with Fe content of 3.09-10.8 wt.% Y are formed.

(2) Alloy proportioning, smelting and modification treatment

Weighing corresponding raw materials according to the component requirement of the Fe-Cr-B-C alloy, and adding 0.02-1.6% of Y element for modification. Firstly Fe-Y₂O₃Or Fe-yttrium nitrate or Fe-yttrium carbonate powder briquettes are placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron are placed in the furnace. The alloy can be prepared by smelting in an induction furnace, a vacuum induction furnace and the like.

The melting temperature is 1500-1660 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1300-1380 ℃, and deoxidizing by using pure aluminum accounting for 0.1-0.15% of the total amount of the ingredients; and keeping the temperature and standing for about 5-10 minutes.

(3) Casting of

The casting temperature range is 1250-1320 ℃, in order to avoid thermal stress cracking, the mold opening temperature is lower than 200 ℃ after casting, and the casting is naturally cooled to the ambient temperature.

The alloy of the invention has deep eutectic composition, and can form non-equilibrium matrix structure, such as amorphous, nanocrystalline or martensite structure, under the condition of common sand mold casting. The alloy melt has good fluidity and can be cast and formed by various methods, such as common sand mold casting or investment casting, lost foam casting, metal mold casting, ceramic mold casting, die casting, centrifugal casting and other special casting methods.

(4) Thermal treatment

And (3) putting the casting into a box furnace for heating, wherein the heating temperature is 950-1060 ℃, and the heat preservation time is 1-4 h. The heating speed is not more than 10 ℃/min.

And after the heat preservation is finished, quickly quenching and cooling the casting in 5-15% of saline water or alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min.

Then tempering at 200-250 ℃ for 2-4 h, and naturally cooling to the ambient temperature.

The iron powder in the step (1) is reduced iron powder with the purity of more than or equal to 98.5 percent and the granularity of 100 meshes or water atomized iron powder with the purity of more than or equal to 99.0 percent and the granularity of 100 meshes or alloy iron powder with equivalent granularity and a small amount of alloy ingredients which do not influence casting. It is also possible to select a powder of smaller particle size, so as to be able to be pressed with green strength that does not affect the preparation of the subsequent charge and burden.

And (2) uniformly mixing the materials in the step (1) into a mixing barrel type mixing material, a V-shaped mixing material or a stirring mixing material to realize substantial uniformity.

The pressed blank in the step (1) is formed by die pressing, the pressing pressure is 100-600 MPa, and the size of the pressed blank is not limited. Cold isostatic pressing methods may also be employed.

Step (2) adding Fe-Y₂O₃The purpose of placing the Fe-yttrium nitrate or Fe-yttrium carbonate powder pressing block at the furnace bottom is as follows: ferrochromium, ferroboron, etc. have a lower melting temperature than pure iron and thus will preferentially melt and infiltrate the Fe-Y in the bottom₂O₃Compacting the powder to gradually melt the pure iron powder and release Y₂O₃Powder particles, or pyrolysis to produce fine Y₂O₃And nitroxides, or pyrolysis to give fine Y₂O₃And CO₂. . Due to Y₂O₃Has a low density of about 5.01g/cm³The melt will gradually float up. At Y₂O₃Process of powder floating up by Fe₃C、Cr₃C₂The isocarbides are reduced to form the active Y element and reacted with C, B to form a catalyst similar to YCrB₄And Y (B, C)₄The compound of (1). By modification of YThe reticular structure and the acicular boride distributed along the crystal disappear, the alloy consists of a primary crystal matrix phase and a eutectic structure, and the eutectic structure is formed by interpenetration of a fine matrix phase and a hard phase, so that the strength and the impact toughness of the alloy are improved.

Y₂O₃The CO gas formed in the powder floating and reaction processes also has the functions of degassing and deslagging, thereby further purifying the melt. Oxynitride and CO₂The floating process is helpful for degassing and deslagging the solution.

If Y is₂O₃Yttrium nitrate or yttrium carbonate powder is easily and quickly floated to the surface of the melt without being prepared into briquettes and placed on the bottom of the furnace, the oxygen content on the surface of the melt is high, and Y is₂O₃Is not easy to be reduced to form active Y, and loses the metamorphic effect.

Said Fe₃C、Cr₃C₂The carbide is formed by the reaction of high carbon ferrochrome and C and Fe element during melting, because of Fe₃C、Cr₃C₂Isocarbides have lower stability at high temperature than Mo₂C and the melting temperature exceeds the 1400 ℃ reaction temperature described in document 1, the partial pressure of CO gas in the melt is also extremely low; since Y has properties similar to those of La, the reduction reaction to form active Y proceeds similarly to document 1. EDS spectroscopy also indicates that the casting alloy phase contains Y element.

And (4) when the quenching temperature is 950-1060 ℃, along with the increase of the quenching temperature, a part of the hard phase is dissolved into the matrix phase, so that the volume fraction of the matrix phase is increased, the content of alloy elements in the matrix phase is also increased, and a martensite structure with higher hardness can be formed after quenching. Thereby ensuring the overall hardness and combination properties.

The structure of cast Fe-Cr-B-C alloy is mainly composed of hard phase (Fe)₂B or M₂B, etc.) and a matrix phase (alpha or martensite phase). The hardness of the alloy depends mainly on the volume ratio of the hard phases, i.e. the higher the hard phase, the greater the hardness of the material. However, the matrix phase has a low strength due to the excessive amount of the hard phase, resulting in a decrease in the overall hardness and insufficient toughness. Thus, in addition to the proportion of hard phase to matrix phase being a determining factor, the matrix phaseIs also important. When the quenching temperature is lower than 950 ℃, a hard phase can be precipitated from the matrix, so that the hardness of the material is reduced, and the impact toughness and the like are reduced. Continuing to raise the quench temperature to 1100 c causes localized overburning in the casting, resulting in a decrease in the toughness of the alloy.

The Y modification method of the invention is not limited to Fe-Cr-B-C alloy, and can also be applied to the smelting modification and refining treatment of other cast iron and steel with higher C content.

The main characteristic of the invention is that Y is directly used₂O₃Yttrium nitrate or yttrium carbonate powder is mixed with iron powder to form powder compact which is used as Y element modified carrier. Utilizing Fe in Fe-Cr-B-C alloy high-temperature melt₃C、Cr₃C₂Reduction of the isocarbides forms the active Y element and reacts with C, B to form a compound similar to YCrB₄And Y (B, C)₄The compound of (2) avoids the appearance of boride net-shaped and needle-shaped structures, promotes the formation of fine eutectic structures, and plays a role in modifying and toughening refined structures. And then through quenching-tempering treatment, the volume fraction, solid solubility and hardness of the matrix phase are increased, so that the coordination relationship between the matrix phase and boron and carbon compounds is improved. After heat treatment, Y is adopted₂O₃The hardness of the cast ingot as a raw material reaches HRC 65.4-68.5, and the impact toughness reaches 13.3-17.1J/cm²The bending strength reaches 1340-1742 MPa, or the hardness of the cast ingot prepared from yttrium nitrate reaches HRC 65.9-69.4, and the impact toughness reaches 12.6-16.6J/cm²The bending strength reaches 1420-1750 MPa, or the hardness of the cast ingot using yttrium carbonate as the raw material reaches HRC 65.8-69.2, and the impact toughness reaches 12.7-16.7J/cm²The bending strength reaches 1462-1740 MPa.

Drawings

FIG. 1 cast structure of example 1 of the invention;

FIG. 2 cast structure of example 9 of the invention;

FIG. 3 cast alloy X-ray diffraction pattern of example 9 of the present invention;

FIG. 4 EDS spectra and composition of matrix phase of casting of example 9 of the invention;

FIG. 5 cast structure of example 17 of the invention.

Detailed Description

The various melting and casting methods of the present invention are not limited by the following examples, and any modifications and variations within the scope of the claims of the present invention are within the scope of the present invention.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium, industrial pure iron, pure iron powder and Y₂O₃Yttrium nitrate, yttrium carbonate powder, pure aluminum and the like are used as raw materials and are prepared into alloy within the composition range required by the invention.

Example 1. iron powder and yttrium carbonate powder were uniformly mixed and then molded into a powder compact. The mass ratio of yttrium carbonate powder to iron powder was approximately 1:3, i.e., an Fe-yttrium carbonate mixed compact of Fe-10.8 wt.% Y was formed. Used as a carrier for rare earth Y modification.

High-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-yttrium carbonate mixed pressing block are selected as raw materials, and the component ranges are as follows: 10.0 wt.% Cr; 2.9 wt.%; 0.7 wt.% C; 0.4 wt.% Nb; 0.2 wt.% V; 1.6 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing the corresponding raw materials according to the required mixture ratio of the components, adopting induction melting and sand mould casting. The method comprises the following specific steps:

putting Fe-yttrium carbonate powder briquettes on the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature was 1650 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1360 ℃, and deoxidizing by using pure aluminum accounting for 0.15 percent of the total amount of the ingredients; the incubation was continued for about 10 minutes. The casting temperature range was 1320 ℃. And opening the mold after casting at a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 950 ℃, and the heat preservation time is 4 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 5% saline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 4h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC67.3, and the impact toughness reachesTo 12.7J/cm²The bending strength reaches 1462 MPa.

FIG. 1 is a drawing of a cast structure of example 1, which is a dark-field phase of a metallographic structure, and an α -Fe matrix phase is black, and other alloy phases are white. As clearly shown in fig. 1, the structure is mainly composed of an Fe primary crystal phase and a eutectic phase, wherein the eutectic phase is a eutectic structure of an Fe phase and boron and carbon compounds, and the structure is very fine.

Example 2. after iron powder and yttrium carbonate powder were mixed uniformly, a powder compact was molded. The mass ratio of yttrium carbonate powder to iron powder was approximately 1:13, i.e., an Fe-yttrium carbonate mixed compact of Fe-3.09 wt.% Y was formed. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, metallic chromium, ferroboron, ferroniobium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: 10.0 wt.% Cr; 2.7 wt.%; 0.7 wt.% C; 0.5 wt.% Nb; y:0.08 wt.%; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After the corresponding raw materials are weighed according to the component requirement, a vacuum induction furnace can be adopted for smelting and water-cooling iron mold casting. The method comprises the following specific steps:

putting Fe-yttrium carbonate powder briquettes on the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium and pure iron. The melting temperature is 1500 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1320 ℃, and deoxidizing by using pure aluminum accounting for 0.1 percent of the total amount of the ingredients; the incubation was continued for about 5 minutes. The casting temperature range was 1260 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1050 ℃, and the heat preservation time is 1 h. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, rapidly quenching and cooling the casting in 15% saline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 250 ℃ for 2h, and naturally cooling to ambient temperature. The integral hardness of the obtained cast ingot reaches HRC69.1, and the impact toughness reaches 13.5J/cm²The bending strength reaches 1530 MPa.

Example 3. iron powder and yttrium carbonate powder were mixed uniformly and molded into a powder compact. The mass ratio of yttrium carbonate powder to iron powder was approximately 1:10, i.e., an Fe-yttrium carbonate mixed compact of Fe-3.93 wt.% Y was formed. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr:10.0 wt.%; b:2.7 wt.%; 0.8wt.% C; 0.6 wt.% Nb; 0.1 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and investment casting, and specifically comprising the following steps:

putting Fe-yttrium carbonate powder briquettes on the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1580 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1320 ℃, and deoxidizing by using pure aluminum accounting for 0.12 percent of the total amount of the ingredients; the incubation was continued for about 8 minutes. The casting temperature range was 1280 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1000 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, rapidly putting the casting into 10% saline water for quenching and cooling. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC66.9, and the impact toughness reaches 16.7J/cm²The bending strength reaches 1610 MPa.

Example 4. iron powder and yttrium carbonate powder were mixed uniformly and molded into a powder compact. The mass ratio of yttrium carbonate powder to iron powder was approximately 1:9, i.e., an Fe-yttrium carbonate mixed compact of Fe-4.32 wt.% Y was formed. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr: 11.0 wt.%; b:2.7 wt.%; 0.7 wt.% C; 0.2 wt.% Nb; 0.4 wt.% V; 0.3 wt.% Y; control of impurity elementsSee table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and sand mold casting, and specifically comprising the following steps:

putting Fe-yttrium carbonate powder briquettes on the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1600 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1340 ℃, and deoxidizing by using pure aluminum accounting for 0.13 percent of the total amount of the ingredients; the incubation was continued for about 9 minutes. The casting temperature range was 1280 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1060 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 5% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 2h, and naturally cooling to ambient temperature. The integral hardness of the obtained cast ingot reaches HRC6.1, and the impact toughness reaches 12.7J/cm²The bending strength reaches 1670 MPa.

Example 5. iron powder and yttrium carbonate powder were uniformly mixed and then molded into a powder compact. The mass ratio of yttrium carbonate powder to iron powder was approximately 1:4, i.e., an Fe-yttrium carbonate mixed compact of Fe-8.64 wt.% Y was formed. Used as a carrier for rare earth Y modification.

High-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-yttrium carbonate mixed pressing block are selected as raw materials, and the component ranges are as follows: cr:10.0 wt.%; b: 2.6 wt.%; c: 0.6 wt.%; nb: 0.3 wt.%; v: 0.1 wt.%; 0.5 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and lost foam casting, and specifically comprising the following steps:

putting Fe-yttrium carbonate powder briquettes on the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1620 ℃; after the melt is completely melted, the power of the electric furnace is reduced, and the melt is meltedAfter the temperature is reduced to 1325 ℃, pure aluminum accounting for 0.12 percent of the total amount of the ingredients is used for deoxidation; the incubation was continued for about 6 minutes. The casting temperature range was 1285 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 980 ℃, and the heat preservation time is 3 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 15% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC69.2, and the impact toughness reaches 14.9J/cm²The bending strength reaches 1482 MPa.

Example 6. iron powder and yttrium carbonate powder were uniformly mixed and then molded into a powder compact. The mass ratio of yttrium carbonate powder to iron powder was approximately 1:5, i.e., an Fe-yttrium carbonate mixed compact of Fe-7.2 wt.% Y was formed. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr:10.0 wt.%; b: 2.6 wt.%; c:0.8 wt.%; nb: 0.8 wt.%; 0.80 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting vacuum induction melting and iron mold casting, and specifically comprising the following steps:

putting Fe-yttrium carbonate powder briquettes on the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1590 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1335 ℃, and deoxidizing by using pure aluminum accounting for 0.14 percent of the total amount of the ingredients; the incubation was continued for about 7 minutes. The casting temperature range was 1290 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1020 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 10% alkaline water. Stirring continuously in the cooling process, and quenching time of more than or equal to 30min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC65.8, and the impact toughness reaches 15.9J/cm²The bending strength reaches 1740 MPa.

Example 7. iron powder and yttrium carbonate powder were uniformly mixed and then molded into a powder compact. The mass ratio of yttrium carbonate powder to iron powder was approximately 1:6, i.e., an Fe-yttrium carbonate mixed compact of Fe-6.17 wt.% Y was formed. Used as a carrier for rare earth Y modification.

High-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-yttrium carbonate mixed pressing block are selected as raw materials, and the component ranges are as follows: cr: 11.0 wt.%; b: 2.6 wt.%; c: 0.9 wt.%; nb:0.2 wt.%; v:0.2 wt.%; 1.0 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After the corresponding raw materials are weighed according to the component requirement, induction melting and lost foam casting can be adopted. The method comprises the following specific steps:

putting Fe-yttrium carbonate powder briquettes on the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1610 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1340 ℃, and deoxidizing by using pure aluminum accounting for 0.13 percent of the total amount of the ingredients; the incubation was continued for about 8 minutes. The casting temperature range was 1270 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1020 ℃, and the heat preservation time is 1 h. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 15% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 4h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC66.9, and the impact toughness reaches 13.5J/cm²The bending strength reaches 1692 MPa.

Example 8. iron powder and yttrium carbonate powder were uniformly mixed and then molded into a powder compact. The mass ratio of yttrium carbonate powder to iron powder was approximately 1:7, i.e., an Fe-yttrium carbonate mixed compact of Fe-5.4 wt.% Y was formed. Used as a carrier for rare earth Y modification.

High-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-yttrium carbonate mixed pressing block are selected as raw materials, and the component ranges are as follows: cr: 13.0 wt.%; b: 2.6 wt.%; c:0.8 wt.%; nb:0.6 wt.%; v:0.4 wt.%; 1.2 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and lost foam casting, and specifically comprising the following steps:

putting Fe-yttrium carbonate powder briquettes on the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1620 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1330 ℃, and deoxidizing by using pure aluminum accounting for 0.12 percent of the total amount of the ingredients; the incubation was continued for about 6 minutes. The casting temperature range was 1270 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 980 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 10% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 2h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC68.1, and the impact toughness reaches 15.7J/cm²The bending strength reaches 1486 MPa.

Example 9. iron powder and yttrium nitrate powder were mixed uniformly and then molded into a powder compact. The mass ratio of yttrium nitrate powder to iron powder was approximately 1:3, i.e., an Fe-yttrium nitrate mixed compact of Fe-5.8 wt.% Y was formed. Used as a carrier for rare earth Y modification.

High-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-yttrium nitrate mixed pressing block are selected as raw materials, and the component ranges are as follows: 10.0 wt.% Cr; 2.9 wt.%; 0.7 wt.% C; 0.4 wt.% Nb; 0.2 wt.% V; 1.0 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing the corresponding raw materials according to the required mixture ratio of the components, adopting induction melting and sand mould casting. The method comprises the following specific steps:

putting the Fe-yttrium nitrate powder briquette at the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1600 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1350 ℃, and deoxidizing by using pure aluminum accounting for 0.15 percent of the total amount of the ingredients; the incubation was continued for about 10 minutes. The casting temperature range was 1300 ℃. And opening the mold after casting at a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 950 ℃, and the heat preservation time is 4 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 5% saline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 4h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC67.5, and the impact toughness reaches 12.6J/cm²The bending strength reaches 1446 MPa.

FIG. 2 is a cast structure diagram of example 2, which is a dark-field phase of a metallographic structure, and the α -Fe matrix phase is black, while the other alloy phases are white. As clearly shown in fig. 2, the structure is mainly composed of an Fe primary crystal phase and a eutectic phase, wherein the eutectic phase is a eutectic structure of an Fe phase and boron and carbon compounds, and the structure is very fine.

(ii) a FIG. 2 is an X-ray diffraction pattern of a cast alloy showing that the alloy matrix is an alpha-Fe phase, the diffraction peak is broad and is broad around 65 degrees, and therefore, the matrix is a martensite phase with a large amount of Cr dissolved in solid, and the carbon and boron compounds are Fe₂B、Fe₃C and Cr₂₃C₆A complex compound based thereon, and shown with Y (B, C)₆The presence of a compound; FIG. 3 is EDS spectrum of matrix phase of cast alloy and analysis result, EDS can only qualitatively analyze components, and result shows that Y element exists in alloy, which shows that Y element exists in alloy₂O₃The Y element is alloyed with the melt to change the quality of the melt.

Example 10. iron powder and yttrium nitrate powder were mixed uniformly and then molded into a powder compact. The mass ratio of yttrium nitrate powder to iron powder was approximately 1:9, i.e., an Fe-yttrium nitrate mixed compact of Fe-2.32 wt.% Y was formed. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, metallic chromium, ferroboron, ferroniobium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: 10.0 wt.% Cr; 2.7 wt.%; 0.7 wt.% C; 0.5 wt.% Nb; 0.05 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After the corresponding raw materials are weighed according to the component requirement, a vacuum induction furnace can be adopted for smelting and water-cooling iron mold casting. The method comprises the following specific steps:

putting the Fe-yttrium nitrate powder briquette on the furnace bottom, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium and pure iron. The melting temperature is 1520 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1300 ℃, and deoxidizing by using pure aluminum accounting for 0.1 percent of the total amount of the ingredients; the incubation was continued for about 5 minutes. The casting temperature range was 1250 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1050 ℃, and the heat preservation time is 1 h. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, rapidly quenching and cooling the casting in 15% saline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 250 ℃ for 2h, and naturally cooling to ambient temperature. The integral hardness of the obtained cast ingot reaches HRC69.3, and the impact toughness reaches 13.4J/cm²The bending strength reaches 1420 MPa.

EXAMPLE 11A powder compact was obtained by uniformly mixing iron powder and yttrium nitrate powder and then molding the mixture. The mass ratio of yttrium nitrate powder to iron powder was approximately 1:7, i.e., an Fe-yttrium nitrate mixed compact of Fe-2.9 wt.% Y was formed. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr:10.0 wt.%; b:2.7 wt.%; 0.8wt.% C; 0.6 wt.% Nb; y:0.08 wt.%; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. Weighing the corresponding raw materials according to the required mixture ratio of the components, and then miningInduction melting and investment casting are used, and the method comprises the following specific steps:

putting the Fe-yttrium nitrate powder briquette at the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1580 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1320 ℃, and deoxidizing by using pure aluminum accounting for 0.12 percent of the total amount of the ingredients; the incubation was continued for about 8 minutes. The casting temperature range was 1280 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1000 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, rapidly putting the casting into 10% saline water for quenching and cooling. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC67.1, and the impact toughness reaches 16.6J/cm²The bending strength reaches 1540 MPa.

Example 12. iron powder and yttrium nitrate powder were mixed uniformly and then molded into a powder compact. The mass ratio of yttrium nitrate powder to iron powder was approximately 1:5, i.e., an Fe-yttrium nitrate mixed compact of Fe-3.87 wt.% Y was formed. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr: 11.0 wt.%; b:2.7 wt.%; 0.7 wt.% C; 0.2 wt.% Nb; 0.4 wt.% V; 0.1 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and sand mold casting, and specifically comprising the following steps:

putting the Fe-yttrium nitrate powder briquette at the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1600 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1340 ℃, and deoxidizing by using pure aluminum accounting for 0.13 percent of the total amount of the ingredients; the incubation was continued for about 9 minutes. The casting temperature range was 1280 ℃. The mold opening temperature is lower than 200 ℃ after castingAnd naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1060 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 5% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 2h, and naturally cooling to ambient temperature. The integral hardness of the obtained cast ingot reaches HRC66.5, and the impact toughness reaches 12.6J/cm²The bending strength reaches 1620 MPa.

EXAMPLE 13 iron powder and yttrium nitrate powder were mixed uniformly and then molded into a powder compact. The mass ratio of yttrium nitrate powder to iron powder was approximately 1:4, i.e., an Fe-yttrium nitrate mixed compact of Fe-4.64 wt.% Y was formed. Used as a carrier for rare earth Y modification.

High-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-yttrium nitrate mixed pressing block are selected as raw materials, and the component ranges are as follows: cr:10.0 wt.%; b: 2.6 wt.%; c: 0.6 wt.%; nb: 0.3 wt.%; v: 0.1 wt.%; 0.2 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and lost foam casting, and specifically comprising the following steps:

putting the Fe-yttrium nitrate powder briquette at the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1600 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1325 ℃, and deoxidizing by using pure aluminum accounting for 0.12 percent of the total amount of the ingredients; the incubation was continued for about 6 minutes. The casting temperature range was 1285 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 980 ℃, and the heat preservation time is 3 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 15% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC69.4, and the impact toughness reaches 14.6J/cm²The bending strength reaches1440MPa。

EXAMPLE 14 iron powder and yttrium nitrate powder were mixed uniformly and then molded into a powder compact. The mass ratio of yttrium nitrate powder to iron powder was approximately 1:8, i.e., an Fe-yttrium nitrate mixed compact of Fe-2.58 wt.% Y was formed. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr:10.0 wt.%; b: 2.6 wt.%; c:0.8 wt.%; nb: 0.8 wt.%; 0.50 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting vacuum induction melting and iron mold casting, and specifically comprising the following steps:

putting the Fe-yttrium nitrate powder briquette at the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1590 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1315 ℃, and deoxidizing by using pure aluminum accounting for 0.14% of the total amount of the ingredients; the incubation was continued for about 7 minutes. The casting temperature range was 1290 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1020 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 10% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC65.9, and the impact toughness reaches 15.7J/cm²The bending strength reaches 1700 MPa.

Example 15. iron powder and yttrium nitrate powder were uniformly mixed and then molded into a powder compact. The mass ratio of yttrium nitrate powder to iron powder was approximately 1:6, i.e., an Fe-yttrium nitrate mixed compact of Fe-3.31 wt.% Y was formed. Used as a carrier for rare earth Y modification.

High-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-yttrium nitrate mixed pressing block are selected as raw materials, and the component ranges are as follows: cr: 11.0 wt.%; b: 2.6 wt.%; c: 0.9 wt.%; nb:0.2 wt.%; v:0.2 wt.%; 0.80 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After the corresponding raw materials are weighed according to the component requirement, induction melting and lost foam casting can be adopted. The method comprises the following specific steps:

putting the Fe-yttrium nitrate powder briquette at the bottom of the furnace, and then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1610 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1340 ℃, and deoxidizing by using pure aluminum accounting for 0.13 percent of the total amount of the ingredients; the incubation was continued for about 8 minutes. The casting temperature range was 1270 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1020 ℃, and the heat preservation time is 1 h. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 15% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 4h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC68.1, and the impact toughness reaches 13.4J/cm²The bending strength reaches 1750 MPa.

EXAMPLE 16 iron powder and yttrium nitrate powder were mixed uniformly and then molded into a powder compact. The mass ratio of yttrium nitrate powder to iron powder was approximately 1:4, i.e., an Fe-yttrium nitrate mixed compact of Fe-4.64 wt.% Y was formed. Used as a carrier for rare earth Y modification.

High-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-yttrium nitrate mixed pressing block are selected as raw materials, and the component ranges are as follows: cr: 13.0 wt.%; b: 2.6 wt.%; c:0.8 wt.%; nb:0.6 wt.%; v:0.4 wt.%; 0.60 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and lost foam casting, and specifically comprising the following steps:

putting the Fe-yttrium nitrate powder briquette on the furnace bottom, and then putting the ferrochrome, the metal chromium,Ferroboron, ferroniobium, ferrovanadium and pure iron. The melting temperature is 1600 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1330 ℃, and deoxidizing by using pure aluminum accounting for 0.12 percent of the total amount of the ingredients; the incubation was continued for about 6 minutes. The casting temperature range was 1270 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 980 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 10% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 2h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC68.5, and the impact toughness reaches 15.8J/cm²The bending strength reaches 1592 MPa.

Example 17 use of iron powder with Y₂O₃After the powders are mixed evenly, the mixture is pressed into powder briquettes. Y is₂O₃The mass ratio of powder to iron powder is approximately 1:4, i.e., Fe-Y forming Fe-15.77 wt.% Y₂O₃And (4) mixing and briquetting. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: 10.0 wt.% Cr; 2.9 wt.%; 0.7 wt.% C; 0.4 wt.% Nb; 0.2 wt.% V; 0.6 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing the corresponding raw materials according to the required mixture ratio of the components, adopting induction melting and sand mould casting. The method comprises the following specific steps:

mixing Fe-Y₂O₃The powder pressing block is placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron are placed in the furnace. The melting temperature is 1660 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1380 ℃, and deoxidizing by using pure aluminum accounting for 0.15 percent of the total amount of the ingredients; the incubation was continued for about 10 minutes. The casting temperature range was 1300 ℃. And opening the mold after casting at a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, and the heating temperature is 950 DEG CThe heat preservation time is 4 h. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 5% saline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 4h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC67.1, and the impact toughness reaches 13.4J/cm²The bending strength reaches 1460 MPa.

FIG. 5 is a drawing of the cast structure of example 17 showing the dark-field phase of the metallographic structure, in which the matrix phase of α -Fe is black and the other alloy phases are white. As clearly shown in fig. 5, the structure is mainly composed of the Fe primary crystal phase and the eutectic phase, wherein the eutectic phase is a eutectic structure of the Fe phase and the boron and carbon compounds, and the structure is very fine.

Example 18 use of iron powder with Y₂O₃After the powders are mixed evenly, the mixture is pressed into powder briquettes. Y is₂O₃The mass ratio of powder to iron powder is approximately 1:20, i.e., Fe-Y forming Fe-3.75 wt.% Y₂O₃And (4) mixing and briquetting. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, metallic chromium, ferroboron, ferroniobium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: 10.0 wt.% Cr; 2.7 wt.%; 0.7 wt.% C; 0.5 wt.% Nb; 0.02 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After the corresponding raw materials are weighed according to the component requirement, a vacuum induction furnace can be adopted for smelting and water-cooling iron mold casting. The method comprises the following specific steps:

mixing Fe-Y₂O₃The powder pressed block is placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium and pure iron are placed in the furnace. The melting temperature is 1560 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1300 ℃, and deoxidizing by using pure aluminum accounting for 0.1 percent of the total amount of the ingredients; the incubation was continued for about 5 minutes. The casting temperature range was 1250 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1050 ℃, and the heat preservation time is 1 h. The heating speed is not more than 10 ℃/min. Heat preservation knotAfter that, the casting is rapidly quenched and cooled in 15% saline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 250 ℃ for 2h, and naturally cooling to ambient temperature. The integral hardness of the obtained cast ingot reaches HRC68.5, and the impact toughness reaches 14.2J/cm²The bending strength reaches 1340 MPa.

Example 19 use of iron powder with Y₂O₃After the powders are mixed evenly, the mixture is pressed into powder briquettes. Y is₂O₃The mass ratio of powder to iron powder is approximately 1:10, i.e., Fe-Y forming Fe-7.17 wt.% Y₂O₃And (4) mixing and briquetting. Used as a carrier for rare earth Y modification.

mixing Fe-Y₂O₃The powder pressing block is placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron are placed in the furnace. The melting temperature is 1580 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1320 ℃, and deoxidizing by using pure aluminum accounting for 0.12 percent of the total amount of the ingredients; the incubation was continued for about 8 minutes. The casting temperature range was 1280 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1000 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, rapidly putting the casting into 10% saline water for quenching and cooling. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC66.5, and the impact toughness reaches 17.1J/cm²The bending strength reaches 1540 MPa.

EXAMPLE 20 iron powder with Y₂O₃Mixing the powders uniformlyAnd then, molding into a powder compact. Y is₂O₃The mass ratio of powder to iron powder is approximately 1:15, i.e., Fe-Y forming Fe-4.93 wt.% Y₂O₃And (4) mixing and briquetting. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr: 11.0 wt.%; b:2.7 wt.%; 0.7 wt.% C; 0.2 wt.% Nb; 0.4 wt.% V; 0.2 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and sand mold casting, and specifically comprising the following steps:

mixing Fe-Y₂O₃The powder pressing block is placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron are placed in the furnace. The melting temperature is 1600 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1340 ℃, and deoxidizing by using pure aluminum accounting for 0.13 percent of the total amount of the ingredients; the incubation was continued for about 9 minutes. The casting temperature range was 1280 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1060 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 5% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 2h, and naturally cooling to ambient temperature. The integral hardness of the obtained cast ingot reaches HRC65.7, and the impact toughness reaches 13.3J/cm²The bending strength reaches 1600 MPa.

Example 21 use of iron powder with Y₂O₃After the powders are mixed evenly, the mixture is pressed into powder briquettes. Y is₂O₃The mass ratio of powder to iron powder is approximately 1:12, i.e., Fe-Y forming Fe-6.06 wt.% Y₂O₃And (4) mixing and briquetting. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-Y₂O₃Mixed briquettes are taken as raw materials to formThe ranges are as follows: cr:10.0 wt.%; b: 2.6 wt.%; c: 0.6 wt.%; nb: 0.3 wt.%; v: 0.1 wt.%; 0.3 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and lost foam casting, and specifically comprising the following steps:

mixing Fe-Y₂O₃The powder pressing block is placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron are placed in the furnace. The melting temperature is 1620 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1325 ℃, and deoxidizing by using pure aluminum accounting for 0.12 percent of the total amount of the ingredients; the incubation was continued for about 6 minutes. The casting temperature range was 1285 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 980 ℃, and the heat preservation time is 3 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 15% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC68.4, and the impact toughness reaches 15.5J/cm²The bending strength reaches 1440 MPa.

EXAMPLE 22 iron powder with Y₂O₃After the powders are mixed evenly, the mixture is pressed into powder briquettes. Y is₂O₃The mass ratio of powder to iron powder is approximately 1:8, i.e., Fe-Y forming Fe-8.76 wt.% Y₂O₃And (4) mixing and briquetting. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr:10.0 wt.%; b: 2.6 wt.%; c:0.8 wt.%; nb: 0.8 wt.%; 0.4 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting vacuum induction melting and iron mold casting, and specifically comprising the following steps:

mixing Fe-Y₂O₃The powder pressing block is placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron are placed in the furnace. The melting temperature is 1590 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1315 ℃, and deoxidizing by using pure aluminum accounting for 0.14% of the total amount of the ingredients; the incubation was continued for about 7 minutes. The casting temperature range was 1290 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1020 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 10% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 220 ℃ for 3h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC65.4, and the impact toughness reaches 16.4J/cm²The bending strength reaches 1626 MPa.

Example 23 use of iron powder with Y₂O₃After the powders are mixed evenly, the mixture is pressed into powder briquettes. Y is₂O₃The mass ratio of powder to iron powder is approximately 1:7, i.e., Fe-Y forming Fe-9.85 wt.% Y₂O₃And (4) mixing and briquetting. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr: 11.0 wt.%; b: 2.6 wt.%; c: 0.9 wt.%; nb:0.2 wt.%; v:0.2 wt.%; 0.5 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After the corresponding raw materials are weighed according to the component requirement, induction melting and lost foam casting can be adopted. The method comprises the following specific steps:

mixing Fe-Y₂O₃The powder pressing block is placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron are placed in the furnace. The melting temperature is 1620 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1350 ℃, and deoxidizing by using pure aluminum accounting for 0.13 percent of the total amount of the ingredients; the incubation was continued for about 8 minutes. The casting temperature range was 1270 ℃. Is cast completelyAnd opening the mold at a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 1020 ℃, and the heat preservation time is 1 h. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 15% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 4h, and naturally cooling to the ambient temperature. The integral hardness of the obtained cast ingot reaches HRC67.3, and the impact toughness reaches 14.0J/cm²The bending strength reaches 1742 MPa.

EXAMPLE 24 iron powder with Y₂O₃After the powders are mixed evenly, the mixture is pressed into powder briquettes. Y is₂O₃The mass ratio of powder to iron powder is approximately 1:6, i.e., Fe-Y forming Fe-11.26 wt.% Y₂O₃And (4) mixing and briquetting. Used as a carrier for rare earth Y modification.

Selecting high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, industrial pure iron and the Fe-Y₂O₃The mixed briquettes are taken as raw materials and have the following component ranges: cr: 13.0 wt.%; b: 2.6 wt.%; c:0.8 wt.%; nb:0.6 wt.%; v:0.4 wt.%; 0.06 wt.% Y; the impurity elements are controlled as shown in Table 2. Small amounts of Al, Mn, N, etc. impurities do not cause radical changes in the properties of the alloy and are therefore not listed in Table 2. After weighing corresponding raw materials according to the component requirement, adopting induction melting and lost foam casting, and specifically comprising the following steps:

mixing Fe-Y₂O₃The powder pressing block is placed at the bottom of the furnace, and then ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron are placed in the furnace. The melting temperature is 1600 ℃; after the materials are completely melted, reducing the power of the electric furnace, reducing the temperature of the melt to 1320 ℃, and deoxidizing by using pure aluminum accounting for 0.12 percent of the total amount of the ingredients; the incubation was continued for about 6 minutes. The casting temperature range was 1260 ℃. And opening the mold after casting to a temperature lower than 200 ℃, and naturally cooling to the ambient temperature. Then the casting is put into a box furnace to be heated, the heating temperature is 980 ℃, and the heat preservation time is 2 hours. The heating speed is not more than 10 ℃/min. And after the heat preservation is finished, quickly quenching and cooling the casting in 10% alkaline water. Stirring continuously in the cooling process, and quenching and cooling time is more than or equal to 30 min. Then tempering at 200 ℃ for 2h, and naturally coolingTo ambient temperature. The integral hardness of the obtained cast ingot reaches HRC67.9, and the impact toughness reaches 16.8J/cm²The bending strength reaches 1512 MPa.

The properties of the cast alloys prepared in the examples were measured as follows:

1. hardness tests were conducted on the cast metals of the examples using an HR-150A Rockwell hardness machine with a load of 150Kg, and an average value was taken after five points were hit and is shown in Table 2.

2. The impact toughness of the cast metals of the examples was tested using a JBS-300B impact tester at a range of 150J, and the average value of five samples was taken and is shown in Table 2.

3. Three-point bending tests were conducted on an electronic universal testing machine for example cast metal materials, with sample dimensions of 2X 5X 50mm rectangular test specimens with a span of 30mm, and the average bending strengths of three identically treated samples are listed in Table 2.

TABLE 2 compositions and hardness, impact toughness and flexural strength of the examples

Claims

1. An yttrium toughened wear-resistant alloy is characterized in that: the mass percentage of each element is Cr: 9.0-13.0, B: 2.6-2.9, C:0.7 to 0.9, Nb: 0.4-0.8, V: 0.4-0.8, Mn content less than 0.3, Y:0.02 to 1.6, S, P: less than or equal to 0.01, and the balance being Fe; wherein C, B comprises the following components in percentage by mass: 3.3 to 3.6; C/Cr mass ratio: 0.06 to 0.08; the total mass percentage of Nb and V is as follows: 0.5 to 1.0; the casting and heat treatment method of the yttrium toughened wear-resistant alloy comprises the following steps:

(1) y-containing powder compact preparation

Using iron powder and Y₂O₃After the powders are mixed evenly, the mixture is molded into powder briquettes Y₂O₃The mass ratio of the powder to the iron powder is 1: 4-20, and Fe is formed-3.75 to 15.77wt.% of Y Fe-Y₂O₃The mixed briquette is used as a carrier for rare earth Y modification; or the mass ratio of the yttrium nitrate powder to the iron powder is 1: 3-9 to form a mixed briquette of Fe-2.32-5.80% Y, or the mass ratio of the yttrium carbonate powder to the iron powder is 1: 3-13 to form a mixed briquette of Fe-3.09-10.8 wt.% Y;

(2) alloy proportioning, smelting and modification treatment

Weighing corresponding raw materials according to the component requirement proportion of the Fe-Cr-B-C alloy, and then adding 0.02-1.6% of Y element for modification: firstly Fe-Y₂O₃Putting a Fe-yttrium carbonate or Fe-yttrium nitrate powder briquette at the bottom of a furnace, then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron, and smelting by adopting an induction furnace to prepare an alloy, wherein the melting temperature is 1500-1660 ℃; then reducing the power of the electric furnace, reducing the temperature of the melt to 1300-1380 ℃, and deoxidizing by using pure aluminum accounting for 0.1-0.15% of the total amount of the ingredients; keeping the temperature and standing for 5-10 minutes;

(3) casting of

The casting temperature range is 1250-1320 ℃, the designed alloy has deep eutectic composition, can form non-equilibrium matrix structure under the condition of common sand mold casting, can be cast and formed by various methods, the mold opening temperature is lower than 200 ℃ after casting, and the alloy is naturally cooled to the ambient temperature in order to avoid thermal stress cracking;

(4) thermal treatment

Putting the casting into a box furnace for heating, heating to 950-1060 ℃, and keeping the temperature for 1-4 h; heating up at a speed of no more than 10 ℃/min, after heat preservation, adding the casting into 5-15% saline water or alkaline water for quenching and cooling, continuously stirring in the cooling process, and quenching and cooling time is no less than 30 min; then tempering at 200-250 ℃ for 2-4 h, and naturally cooling to the ambient temperature;

y for directly using yttrium toughened wear-resistant alloy₂O₃Mixing yttrium nitrate or yttrium carbonate powder with iron powder to form powder compact serving as a Y element modification carrier; utilizing Fe in Fe-Cr-B-C alloy high-temperature melt₃C、Cr₃C₂Reduction of the isocarbides forms the active Y element and reacts with C, B to form a compound similar to YCrB₄And Y (B, C)₄The compound of (a) to (b),avoiding boride net and needle structures, promoting the formation of fine eutectic structures and playing a role in modifying and toughening refined structures; then through quenching-tempering treatment, the volume fraction, solid solubility and hardness of the matrix phase are increased, so that the coordination relationship between the matrix phase and boron and carbon compounds is improved; after heat treatment, Y is adopted₂O₃When the alloy is used as a raw material, the hardness of the cast ingot reaches HRC 65.4-68.5, and the impact toughness reaches 13.3-17.1J/cm²The bending strength reaches 1340 to 1742 MPa; when yttrium nitrate is used as a raw material, the hardness of the cast ingot reaches HRC 65.9-69.4, and the impact toughness reaches 12.6-16.6J/cm²The bending strength reaches 1420-1750 MPa; or when the yttrium carbonate is used as the raw material, the hardness of the cast ingot reaches HRC 65.8-69.2, and the impact toughness reaches 12.7-16.7J/cm²The bending strength reaches 1462-1740 MPa.

2. A method of casting and heat treating a yttrium toughened wear resistant alloy as claimed in claim 1, comprising the steps of:

(1) y-containing powder compact preparation

Using iron powder and Y₂O₃After the powders are mixed evenly, the mixture is molded into powder briquettes Y₂O₃The mass ratio of the powder to the iron powder is 1: 4-20, and Fe-Y of Fe-3.75-15.77 wt.% Y is formed₂O₃The mixed briquette is used as a carrier for rare earth Y modification; or the mass ratio of the yttrium nitrate powder to the iron powder is 1: 3-9 to form a mixed briquette of Fe-2.32-5.80% Y, or the mass ratio of the yttrium carbonate powder to the iron powder is 1: 3-13 to form a mixed briquette of Fe-3.09-10.8 wt.% Y;

(2) alloy proportioning, smelting and modification treatment

Weighing corresponding raw materials according to the component requirement proportion of the Fe-Cr-B-C alloy, and then adding 0.02-1.6% of Y element for modification: firstly Fe-Y₂O₃Putting a Fe-yttrium carbonate or Fe-yttrium nitrate powder briquette at the bottom of a furnace, then putting ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium and pure iron, and smelting by adopting an induction furnace to prepare an alloy, wherein the melting temperature is 1500-1660 ℃; then reducing the power of the electric furnace, reducing the temperature of the melt to 1300-1380 ℃, and deoxidizing by using pure aluminum accounting for 0.1-0.15% of the total amount of the ingredients; keep warm continuously and stand 5 ^ to10 minutes;

(3) casting of

(4) thermal treatment

Putting the casting into a box furnace for heating, heating to 950-1060 ℃, and keeping the temperature for 1-4 h; heating up at a speed of no more than 10 ℃/min, after heat preservation, adding the casting into 5-15% saline water or alkaline water for quenching and cooling, continuously stirring in the cooling process, and quenching and cooling time is no less than 30 min; then tempering at 200-250 ℃ for 2-4 h, and naturally cooling to the ambient temperature.

3. A method of casting and heat treating a yttrium toughened wear resistant alloy as claimed in claim 2, wherein: the iron powder in the step (1) is reduced iron powder with the purity of more than or equal to 98.5 percent and the granularity of 100 meshes, or water atomized iron powder with the purity of more than or equal to 99.0 percent and the granularity of 100 meshes, or alloy iron powder with the granularity of 100 meshes.

4. A method of casting and heat treating a yttrium toughened wear resistant alloy as claimed in claim 2, wherein: and (2) the pressing pressure of the die pressing in the step (1) is 100-600 MPa.