CN108425073A - A kind of Si strengthens high hardness wear-resisting alloy and its casting and heat treatment method - Google Patents

Abstract

A kind of Si strengthens high hardness wear-resisting alloy and its casting and heat treatment method, and the content of alloy each element is Cr：9.0~13.0, B：2.6~2.9, C：0.7~0.9, Si：0.6~1.5%, Nb：0.4~0.8, V：0.4~0.8, Mn are less than 0.3, and surplus Fe, C, B total amount is 3.3~3.6；C/Cr content ratios：0.06~0.08；The total amount of Nb, V are 0.5~1.0, first melt other raw materials other than ferrosilicon at 1520~1620 DEG C, are cooled to 1300~1350 DEG C, add fine aluminium deoxidation；1280~1320 DEG C are dropped to after heat preservation, add ferrosilicon, 1250~1300 DEG C of cast alloys, and handle by Q-tempering.65.3~68HRC of alloy rigidity of the present invention, 9.2~12.6J/cm of impact flexibility², 1120~1300MPa of bending strength.

Description

A kind of Si reinforced high hardness wear-resistant alloy and its casting and heat treatment method

technical field

The invention belongs to the field of high-hardness wear-resistant cast iron, and relates to an alloy casting and heat treatment method of wear-resistant and corrosion-resistant cast iron containing ultrafine hard phase, supersaturated solid solution and martensitic matrix phase, which can be widely used in electric power, metallurgy, Manufacture of mechanical wear-resistant parts in machinery, chemical industry and other industries.

technical background

Fe-Cr-BC wear-resistant casting alloy is based on Fe ₂ B or M ₂ B hard phase, which has good toughness, high hardness, high corrosion resistance, good melting and casting process, and has a very wide range of applications. Application prospect.

Patent document 1: Authorized announcement number CN 105695884B, the prepared wear-resistant alloy has a hardness of HRC66-70 and an impact toughness of 4-9J/cm ² . When preparing castings with large size specifications (thickness greater than 30mm) and complex shapes, thermal stress cracks will appear, and there will be uneven hardness distribution. Wear parts such as grinding balls, liners, hammer heads, tooth plates, flow parts, impellers and other wear parts used in large-scale Raymond grinders, ore crushers, slurry pumps, etc., are bulky and complex in shape, so Patent Document 1 The process method used limits the application of this alloy.

The hardness of this type of alloy is high, but the impact toughness is insufficient, the strength index is low, and the bending strength is low, ranging from 346 to 477 MPa, which limits the application of this alloy to some occasions where the external load is large and impact resistance is required.

Document 2: Rapid cooling microstructure and properties of eutectic Fe-Cr-BC alloy, Casting, 2017, 66(10): 1053-1056. The rapidly cooled microstructure of as-cast Fe-Cr-BC alloy consists of martensite + retained austenite matrix and (Fe,Cr) ₂ (B,C)+(Fe,Cr) ₂₃ ( B,C) Composition of ₆ hard phases. The microhardness of the matrix phase of the fast-cooled structure is 800-880HV, the microhardness of the hard phase is 1150-1400HV, the macroscopic hardness is HRC68, and the impact toughness reaches 13.6J/ ^cm2 ; It transforms into ferrite and granular cementite, the hard phases (Fe,Cr) ₂ (B,C) and (Fe,Cr) ₂₃ (B,C) ₆ are dissolved in a small amount, and the network is broken in some areas, and new phases appear (Fe,Cr) ₃ (B,C), the microhardness of the matrix phase after annealing is 330~400HV, the hard phase is 850~1250HV, the macrohardness is reduced to HRC46, and the impact toughness is reduced to 3.4J/cm ² .

The results obtained in Document 2 reflect that the hardness of the matrix phase plays an important role in the hardness and impact toughness of this type of material; compared with Patent Document 1, this type of alloy has the possibility of improving impact toughness and other properties.

Contents of the invention

The object of the present invention is to provide a Si-strengthened high-hardness wear-resistant alloy and its casting and heat treatment method. The alloy uses Fe ₂ B or M ₂ B as the hard phase, and the matrix is a high-hardness multi-component supersaturated alloy strengthened by Si element solid solution. Solid solution, martensite and other non-equilibrium phases have good toughness, high hardness and high strength index, good smelting, casting and heat treatment processability, and have very broad application prospects.

In the invention, the Fe-Cr-B-C alloy with high wear resistance and high corrosion resistance is selected as the basic alloy, and 0.6-1.5% Si element is added. Form a multi-element eutectic alloy containing Fe, Cr, B, C, Nb, V, Si and other elements, the mass percentage of each element is Cr: 9.0~13.0, B: 2.6~2.9, C: 0.7~0.9, Si : 0.6～1.5%, Nb: 0.4～0.8, V: 0.4～0.8, the content of Mn is less than 0.3, S, P: ≤0.01, and the balance is Fe. Among them, the sum of C and B: 3.3-3.6; the content ratio of C/Cr: 0.06-0.08; the sum of Nb and V is 0.5-1.0.

Fe-Si alloy is a traditional electrical steel, its strength and hardness increase rapidly with the increase of Si content, Fe-Si alloy with Si content less than 4.5% is a single ferrite phase, and after more than 4.5%, it will be Ordering occurs, forming a hard and brittle phase of _DO structure. Because there is a large amount of _Fe2B or _M2B in the present invention as a hard phase, the volume ratio of the matrix phase is about 50-60%, and the added Si is mainly dissolved in the matrix phase, so the Si content should be controlled In 0.6 ~ 1.5%, in order to prevent the matrix phase is too hard and brittle.

In general cast iron, Si element is mainly dissolved in the matrix to increase its strength, and has a deoxidation effect during smelting, which improves the solidification characteristics of the alloy, but reduces the toughness of the alloy, and promotes crystallization and grain coarsening. However, in the alloy of the present invention, due to the presence of a large number of borides, the melting point of the alloy is lowered, and the crystallization temperature is low, so that the tendency of grain coarsening is weakened.

Referring to Patent Document 1, in specific preparation of alloys, ferrochrome (high carbon, medium carbon, micro carbon), ferroboron, ferroniobium, ferrovanadium, ferrosilicon and pure iron can be used as ingredients according to the composition requirements. Table 1 lists the raw materials and their components.

Table 1 can be applied to the raw material and composition of preparation invention alloy

The raw material composition in Table 1 is not unique, and the specific composition is determined by the actually available raw materials. Among them, ferrochrome, metal chromium, ferroboron, ferroniobium and ferrovanadium provide the content of Cr, B, Nb and V of the invention alloy, and high carbon ferrochrome is used to balance the C content. The pure iron can be electrical pure iron, electromagnetic pure iron or industrial pure iron.

The grade of ferrosilicon listed in Table 1 is FeSi ₇₅ Al _1.5 , and other grades of ferrosilicon can also be used. Since ferrosilicon is a deoxidizer in the steelmaking industry, when the oxygen content of the melt is high or the temperature is high, Si will be oxidized in large quantities to form slag. The body is deoxidized by aluminum.

The specific melting, casting and heat treatment processes are:

After weighing the corresponding raw materials according to the composition requirements, induction furnaces, vacuum induction furnaces, etc. can be used to smelt and prepare alloys. First melt ferrochromium, metallic chromium, ferroboron, ferro-niobium, ferrovanadium and pure iron at a melting temperature higher than 1540-1620°C to fully melt pure iron and metallic chromium; then reduce the power of the electric furnace to lower the melt temperature to After 1300-1350°C, use 0.1-0.15% of the total amount of pure aluminum for deoxidation; continue to keep warm for about 5-10 minutes, and when the melt temperature is 1280-1320°C, add the weighed ferrosilicon; after it is completely melted , rapid casting alloy, casting temperature range of 1250 ~ 1300 ℃.

Since the designed alloy is a deep eutectic composition, the addition of Si further increases the fluidity, so the melt has very good fluidity, so it can be casted by various methods, such as ordinary sand mold casting , investment casting or lost foam casting.

In order to avoid thermal stress cracking, the mold opening temperature should be lower than 200°C after casting. Allow to cool naturally.

Then put the casting into a box furnace for heating, the heating temperature is 950-1060°C, and the holding time is 1-4h. The heating rate does not exceed 10°C/min.

After the heat preservation is over, quickly put the casting into 5-15% brine or alkaline water for quenching and cooling. Stir continuously during the cooling process, and the quenching cooling time is ≥30min.

Then temper at 200-250°C for 2-4 hours, and cool naturally.

After the above quenching-tempering treatment, the prepared Fe-Cr-Si-BC alloy has a hardness of 65.3-68HRC, an impact toughness of 9.2-12.6J/cm ² , and a bending strength of 1120-1300MPa.

Compared with Patent Document 1, the hardness is slightly reduced, but the impact toughness and bending strength are greatly improved, and can be used to produce wear-resistant castings with large sizes or complex shapes.

The microstructure of cast Fe-Cr-Si-BC alloy is mainly composed of hard phase (Fe ₂ B or M ₂ B, etc.) and matrix phase (α or martensite phase). The hardness of the alloy mainly depends on the volume ratio of the hard phase, that is, the higher the hard phase, the greater the hardness of the material. However, due to too many hard phases, the strength of the matrix phase is low, which will lead to a decrease in the overall hardness and insufficient toughness. Therefore, in addition to the ratio of hard phase to matrix phase being the determining factor, the properties of the matrix phase are also important.

When the alloy is prepared by the method of Patent Document 1, when the size is large, the temperature distribution in the solidification process is not uniform, so that the distribution and properties of the matrix phase are different in different parts of the casting, so it is easy to cause thermal stress cracking and uneven performance. Through reheating, the overall temperature of the casting can be made uniform, and then quenched quickly to obtain a homogeneous and high-hardness casting.

When the quenching temperature is lower than 950°C, the hard phase will precipitate from the matrix, resulting in a decrease in material hardness and impact toughness.

When the quenching temperature is 950-1060°C, as the quenching temperature increases, part of the hard phase dissolves into the matrix phase, which increases the volume fraction of the matrix phase, and at the same time increases the content of alloy elements in the matrix phase. High hardness martensitic structure. Thus ensuring the overall hardness and comprehensive performance.

Continuing to increase the quenching temperature to 1100 °C will cause local overburning in the casting, which will reduce the toughness of the alloy.

The main feature of the invention is that multi-phase eutectic of hard phase and matrix phase is formed through multi-element alloying, and then quenched and tempered. The volume fraction of the matrix phase increases, while the volume fraction of the hard phase decreases. Si element is specially added to solid-solution strengthen the matrix phase with elements such as Cr, B, C, etc., reduce the martensite transformation temperature, and refine the matrix martensite structure, so that the hardness of the matrix phase exceeds the hardness of the ordinary martensite phase, thereby improving The coordination between the hard phase and the matrix phase improves the impact toughness and flexural strength of the alloy.

Description of drawings

Fig. 1 cast metallographic structure of Example 1 of the present invention;

The metallographic structure of Fig. 2 Example 1 of the present invention after quenching-tempering treatment;

Fig. 3 is the X-ray diffraction spectrum of Example 1 of the present invention after quenching-tempering treatment.

Detailed ways

Various smelting methods and casting methods of the present invention are not limited by the following examples, and any improvements and changes within the scope of the claims of the present invention are within the protection scope of the present invention.

High-carbon ferrochrome, micro-carbon ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium, industrial pure iron, ferrosilicon, etc. are selected as raw materials and formulated into alloys within the composition range required by the invention.

Embodiment 1. Select high-carbon ferrochrome, microcarbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, ferrosilicon and industrial pure iron as raw materials, and the composition range is as follows: Cr: 10.0wt.%; B: 2.9wt.% ; C: 0.7wt.%; Si: 0.6wt.%; Nb: 0.4wt.%; V: 0.2wt.%;

After weighing the corresponding raw materials according to the composition requirements, induction melting and sand mold casting are adopted. The specific steps are:

First, high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferro-niobium, ferro-vanadium and industrial pure iron are melted at 1620°C; then the power of the electric furnace is reduced, and the melt temperature is reduced to 1300°C. Deoxidize with 0.15% pure aluminum; continue to keep warm for about 5 minutes, and when the melt temperature is 1320°C, add the weighed ferrosilicon; after it is completely melted, quickly cast the alloy, and the casting temperature range is 1250°C. After casting, the mold opening temperature is lower than 200°C and cooled naturally.

Figure 1 shows the metallographic structure of the as-cast alloy. There are a large number of square matrix phases, and the eutectic structure in which the matrix phase and the hard phase are interspersed. The structure is relatively fine and uniform.

Then put the casting into the box furnace for heating, the heating temperature is 950°C, and the holding time is 4h. The heating rate does not exceed 10°C/min. After the heat preservation is over, quickly quench and cool the casting into 5% brine. Stir continuously during the cooling process, and the quenching cooling time is ≥30min. Then temper at 200°C for 4h and cool naturally.

Figure 2 shows the metallographic structure after quenching and tempering treatment. Compared with Figure 1, the number of matrix phases increases, but it still maintains a fine and uniform structure. Figure 3 is the X-ray diffraction pattern of the alloy in this state, reflecting that the alloy is mainly a martensite matrix phase and a boride hard phase. Due to the fine structure, both the matrix phase and the hard phase have high hardness, and the interface is well bonded, so the alloy exhibits high impact toughness and bending strength while maintaining high hardness.

After the above quenching-tempering treatment, the hardness of the alloy reaches HRC65.3, the impact toughness reaches 12.6J/cm ² , and the bending strength reaches 1300MPa.

Embodiment 2. Select high-carbon ferrochrome, metal chromium, ferroboron, ferroniobium, ferrosilicon and industrial pure iron as raw materials, and the composition range is as follows: Cr: 10.0wt.%; B: 2.7wt.%; Si: 0.9wt.% .%; C: 0.7wt.%; Nb: 0.5wt.%; See Table 2 for the control of impurity elements.

After weighing the corresponding raw materials according to the composition requirements, the vacuum induction furnace can be used for melting and water-cooled iron mold casting. The specific steps are:

First, high-carbon ferrochromium, metallic chromium, ferroboron, ferro-niobium and industrial pure iron are melted at a temperature of 1580°C; then the power of the electric furnace is reduced, and the melt temperature is lowered to 1350°C, and the total amount of ingredients is 0.1% of pure aluminum Deoxidation; continue to keep warm for about 10 minutes, when the melt temperature is 1280°C, add the weighed ferrosilicon; after it is completely melted, quickly cast the alloy, and the casting temperature range is 1300°C. After casting, the mold opening temperature should be lower than 200°C, and it should be cooled naturally.

Then put the casting into the box furnace for heating, the heating temperature is 1050°C, and the holding time is 1h. The heating rate does not exceed 10°C/min. After the heat preservation is over, quickly quench and cool the casting into 15% brine. Stir continuously during the cooling process, and the quenching cooling time is ≥30min. Then temper at 250°C for 2h and cool naturally.

After the above quenching-tempering treatment, the prepared Fe-Cr-Si-BC alloy has a hardness of 66.7HRC, an impact toughness of 11.6J/cm ² , and a bending strength of 1260MPa.

Embodiment 3. Select high-carbon ferrochrome, microcarbon ferrochrome, ferroboron, ferro-niobium, ferrosilicon and industrial pure iron as raw materials, and the composition range is as follows: Cr: 10.0wt.%; B: 2.7wt.%; Si: 1.2wt.%; C: 0.8wt.%; Nb: 0.6wt.%; See Table 2 for the control of impurity elements.

After weighing the corresponding raw materials according to the composition requirements, induction melting and investment casting are adopted. The specific steps are:

First, high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferro-niobium and industrial pure iron are melted at a melting temperature of 1600°C; then the power of the electric furnace is reduced to lower the melt temperature to 1320°C, and the total amount of ingredients is 0.12%. Deoxidize pure aluminum; continue to keep warm for about 8 minutes, and when the melt temperature is 1300°C, add the weighed ferrosilicon; after it is completely melted, quickly cast the alloy, and the casting temperature range is 1280°C. After casting, the mold opening temperature should be lower than 200°C. Allow to cool naturally.

Then put the casting into the box furnace for heating, the heating temperature is 1000°C, and the holding time is 2h. The heating rate does not exceed 10°C/min. After the heat preservation is over, quickly quench and cool the casting into 10% brine. Stir continuously during the cooling process, and the quenching cooling time is ≥30min. Then temper at 220°C for 3h and cool naturally.

After the above quenching-tempering treatment, the prepared Fe-Cr-Si-BC alloy has a hardness of 67.2HRC, an impact toughness of 9.8J/cm ² and a bending strength of 1198MPa.

Embodiment 4. select high-carbon ferrochrome, metal chromium, ferroboron, ferroniobium, ferrovanadium, ferrosilicon and industrial pure iron as raw materials, the composition range is as follows: Cr: 11.0wt.%; B: 2.7wt.%; Si : 1.5wt.%; C: 0.7wt.%; Nb: 0.2wt.%; V: 0.4wt.%; See Table 2 for the control of impurity elements.

After weighing the corresponding raw materials according to the composition requirements, induction melting and sand casting are adopted. The specific steps are:

First, melt high-carbon ferrochromium, metal chromium, ferroboron, ferro-niobium, ferro-vanadium and industrial pure iron at a melting temperature of 1540°C; then reduce the power of the electric furnace to lower the melt temperature to 1300°C, and use a total amount of ingredients of 0.14 % pure aluminum deoxidation; continue to keep warm for about 7 minutes, when the melt temperature is 1280 ℃, add the weighed ferrosilicon; after it is completely melted, quickly cast the alloy, the casting temperature range is 1250 ℃. After casting, the mold opening temperature should be lower than 200°C. Allow to cool naturally.

Then put the casting into the box furnace for heating, the heating temperature is 1060°C, and the holding time is 2h. The heating rate does not exceed 10°C/min. After the heat preservation is over, quickly quench and cool the casting into 5% alkaline water. Stir continuously during the cooling process, and the quenching cooling time is ≥30min. Then temper at 220°C for 2h and cool naturally.

After the above quenching-tempering treatment, the prepared Fe-Cr-Si-BC alloy has a hardness of 68HRC, an impact toughness of 9.2J/cm ² , and a bending strength of 1120MPa.

Embodiment 5. Select high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, ferrosilicon and industrial pure iron as raw materials, and the composition range is as follows: Cr: 10.0wt.%; B: 2.6wt.% ; C: 0.6wt.%; Si: 0.6wt.%; Nb: 0.3wt.%; V: 0.1wt.%;

After weighing the corresponding raw materials according to the composition requirements, induction melting and lost foam casting are adopted. The specific steps are as follows:

First, melt high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferro-niobium, ferro-vanadium, and industrial pure iron at a melting temperature of 1580°C; then reduce the power of the electric furnace to lower the melt temperature to 1320°C, Measure 0.12% pure aluminum for deoxidation; continue to keep warm for about 9 minutes, and when the melt temperature is 1280°C, add the weighed ferrosilicon; after it is completely melted, quickly cast the alloy, and the casting temperature range is 1250°C. After casting, the mold opening temperature should be lower than 200°C. Allow to cool naturally.

Then put the casting into the box furnace for heating, the heating temperature is 980°C, and the holding time is 3h. The heating rate does not exceed 10°C/min. After the heat preservation is over, quickly quench and cool the casting into 15% alkaline water. Stir continuously during the cooling process, and the quenching cooling time is ≥30min. Then temper at 220°C for 3h and cool naturally.

After the above quenching-tempering treatment, the prepared Fe-Cr-Si-BC alloy has a hardness of 66.2HRC, an impact toughness of 12.0J/cm ² , and a bending strength of 1248MPa.

Embodiment 6. Select high-carbon ferrochrome, microcarbon ferrochrome, ferroboron, ferro-niobium, ferrosilicon and industrial pure iron as raw materials, and the composition range is as follows: Cr: 10.0wt.%; B: 2.6wt.%; Si: 0.9wt.%; C: 0.8wt.%; Nb: 0.8wt.%; See Table 2 for impurity element control.

After weighing the corresponding raw materials according to the composition requirements, vacuum induction melting and iron mold casting are adopted. The specific steps are as follows:

First, high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferro-niobium and industrial pure iron are melted at 1600°C; then the power of the electric furnace is reduced, and the melt temperature is lowered to 1350°C, and then 0.15% of the total amount of ingredients is used. Deoxidize pure aluminum; continue to keep warm for about 10 minutes, and when the melt temperature is 1320°C, add the weighed ferrosilicon; after it is completely melted, quickly cast the alloy, and the casting temperature range is 1300°C. After casting, the mold opening temperature should be lower than 200°C. Allow to cool naturally.

Then put the casting into a box furnace for heating, the heating temperature is 1020°C, and the holding time is 2h. The heating rate does not exceed 10°C/min. After the heat preservation is over, quickly quench and cool the casting into 10% alkaline water. Stir continuously during the cooling process, and the quenching cooling time is ≥30min. Then temper at 220°C for 3h and cool naturally.

After the above quenching-tempering treatment, the prepared Fe-Cr-Si-BC alloy has a hardness of 66.8HRC, an impact toughness of 10.8J/cm ² , and a bending strength of 1266MPa.

Embodiment 7. Select high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrovanadium, ferrosilicon and industrial pure iron as raw materials, and the composition range is as follows: Cr: 11.0wt.%; B: 2.6wt.% ; Si: 1.2wt.%; C: 0.9wt.%; Nb: 0.2wt.%; V: 0.2wt.%;

After weighing the corresponding raw materials according to the composition requirements, induction melting and lost foam casting can be used. Specific steps are as follows:

First, high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferro-niobium, ferro-vanadium and industrial pure iron are melted at a melting temperature of 1580°C; then the power of the electric furnace is reduced, and the melt temperature is lowered to 1300°C. Measure 0.10% pure aluminum for deoxidation; continue to keep warm for about 5 minutes, and when the melt temperature is 1280°C, add the weighed ferrosilicon; after it is completely melted, quickly cast the alloy, and the casting temperature range is 1250°C. After casting, the mold opening temperature should be lower than 200°C. Allow to cool naturally.

Then put the casting into a box furnace for heating, the heating temperature is 1020°C, and the holding time is 1h. The heating rate does not exceed 10°C/min. After the heat preservation is over, quickly quench and cool the casting into 15% alkaline water. Stir continuously during the cooling process, and the quenching cooling time is ≥30min. Then temper at 200°C for 4h and cool naturally.

After the above quenching-tempering treatment, the prepared Fe-Cr-Si-BC alloy has a hardness of 67.6HRC, an impact toughness of 10.6J/cm ² , and a bending strength of 1186MPa.

Embodiment 8. Select high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferroniobium, ferrosilicon, ferrovanadium and industrial pure iron as raw materials, and the composition range is as follows: Cr: 13.0wt.%; B: 2.6wt.% ; Si: 1.5wt.%; C: 0.8wt.%; Nb: 0.6wt.%; V: 0.4wt.%;

After weighing the corresponding raw materials according to the composition requirements, induction melting and lost foam casting are adopted. The specific steps are as follows:

First, high-carbon ferrochrome, micro-carbon ferrochrome, ferroboron, ferro-niobium, ferro-vanadium and industrial pure iron are melted at a melting temperature of 1590°C; then the power of the electric furnace is reduced, and the melt temperature is lowered to 1320°C. Measure 0.13% pure aluminum for deoxidation; continue to keep warm for about 7 minutes, and when the melt temperature is 1300°C, add the weighed ferrosilicon; after it is completely melted, quickly cast the alloy, and the casting temperature range is 1280°C. After casting, the mold opening temperature should be lower than 200°C. Allow to cool naturally.

Then put the casting into a box furnace for heating, the heating temperature is 980°C, and the holding time is 2h. The heating rate does not exceed 10°C/min. After the heat preservation is over, quickly quench and cool the casting into 10% alkaline water. Stir continuously during the cooling process, and the quenching cooling time is ≥30min. Then temper at 200°C for 2h and cool naturally.

After the above quenching-tempering treatment, the prepared Fe-Cr-Si-BC alloy has a hardness of 66.9HRC, an impact toughness of 11.6J/cm ² , and a bending strength of 1260MPa.

The cast alloy performance detection prepared by each embodiment is as follows:

1. The HR-150A Rockwell hardness machine is used for the hardness test of the cast metal of the example, the load is 150Kg, and the average value is taken after five points are punched, which are listed in Table 2.

2. The JBS-300B impact testing machine is used to test the impact toughness of the cast metal of the example, the measuring range is 150J, and the average value is taken after five samples are made, which are listed in Table 2.

3. Conduct a three-point bending test on the electronic universal testing machine for cast metal materials in the example. The sample size is a rectangular sample of 2×5×50mm, and the span is 30mm. The average value of the bending strength of three similarly processed samples is listed in Table 2.

Composition and hardness, impact toughness and flexural strength of table 2 embodiment

Claims (3)

1. a kind of Si strengthens high hardness wear-resisting alloy, it is characterised in that：The mass percentage of alloy each element is Cr：9.0~ 13.0 B：2.6~2.9, C：0.7~0.9, Si：0.6~1.5%, Nb：0.4~0.8, V：The content of 0.4~0.8, Mn are less than 0.3, Si content is less than 0.07, S, P：≤ 0.01, surplus Fe, wherein C, B gross mass percentage composition are：3.3~3.6；C/ Cr content ratios：0.06~0.08；The gross mass percentage composition of Nb, V are 0.5~1.0.

2. Si as described in claim 1 strengthens casting and the heat treatment method of high hardness wear-resisting alloy, it is characterised in that including Following steps：After weighing good corresponding raw material according to component requirements proportioning, alloy is prepared using induction furnace melting, first by chromium Then iron, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure iron fusing, 1540~1620 DEG C of fusion temperature reduce furnace power, will melt After temperature is down to 1300~1350 DEG C, with the fine aluminium deoxidation of dispensing total amount 0.1~0.15%；Continue heat preservation about 5~10 minutes, Load weighted ferrosilicon, cast alloys, ranging from 1280~1320 DEG C of cast temperature is added；From setting temperature to 600 DEG C Cooling velocity should be not less than 60 DEG C/min, be realized by placing chill in water cooling, swage or mold.

3. Si as described in claim 1 strengthens the preparation method of high hardness wear-resisting alloy, it is characterised in that：Prepare heavy castings When, casting should release the constraint of mold between 600~800 DEG C.