Wear-resistant and corrosion-resistant material applied to slurry pump and preparation method of wear-resistant and corrosion-resistant material

Abstract

The invention relates to the technical field of materials, in particular to a wear-resistant and corrosion-resistant material applied to a slurry pump and a preparation method thereof.The wear-resistant and corrosion-resistant material applied to the slurry pump comprises, by mass, 1.5%-2.0% of C, 1.0%-1.4% of Si, 0.5%-1.5% of Mn, 32%-34% of Cr, 1.8%-2.2% of Ni, 1.8%-2.2% of Mo, 1.1%-1.5% of Cu, less than or equal to 0.06% of S, less than or equal to 0.1% of P, 0.1%-0.5% of V, 0.02%-0.1% of PrC2 and the balance Fe. According to the material provided by the invention, the problem of coexistence of corrosion resistance and wear resistance is solved, the alloy containing various metals is adopted to achieve good wear resistance and corrosion resistance effects, the material has practicability in strength, under the condition, electric corrosion in the alloy is inhibited by adding praseodymium carbide, and the service life of the material is prolonged while the performance of the material is not influenced.

Description

Technical Field

[0001] The invention relates to the technical field of slurry pumps, and in particular to a wear-resistant and corrosion-resistant material used in slurry pumps and a preparation method thereof. Background Art

[0002] Slurry pumps are widely used in mining, power plants, dredging, metallurgy, chemicals, building materials, petroleum and other fields for the transportation of materials. Their flow-through parts (impellers, volutes, and guard plates) are constantly subjected to the scouring, corrosion, and impact of the medium. They are conventional consumables, and their service life directly restricts the production efficiency and output of production units. Hydrometallurgy is a scientific technology that uses leaching agents to dissolve the valuable metal components in ores, concentrates, roasted sand and other materials in solutions or precipitate them as new solid phases for metal separation, enrichment and extraction. Relatively cheap sulfuric acid is usually used, and the transportation equipment is affected by corrosion. The commonly used materials for slurry pumps in the hydrometallurgical industry are engineering plastics and stainless steel, which have poor wear resistance and frequent parts replacement, which seriously restricts the production efficiency of enterprises and increases maintenance costs. It is a bottleneck restricting the development of the industry.

[0003] Ordinary slurry pumps can solve the problem of wear resistance and meet the working requirements for alkaline or weakly acidic media. However, for strong acid (PH approximately equal to 1), bidirectional stainless steel or titanium alloy is currently used. These materials meet the requirements of corrosion resistance but are not wear-resistant.

[0004] In the desulfurization industry, corrosion and wear also exist at the same time, but the acidity is much weaker, with a pH value of about 4, and the corrosion is mainly caused by Cl ions. Therefore, it is necessary to explore materials for working conditions where strong acid and wear exist at the same time. Summary of the invention

[0005] Based on this, the present invention proposes a wear-resistant and corrosion-resistant material for a slurry pump and a preparation method thereof, which has good antioxidant and corrosion resistance, and good strength, as well as good economy and environmental friendliness.

[0006] According to a first aspect of the present invention, there is provided a wear-resistant and corrosion-resistant material for a slurry pump, comprising, by mass: C 1.5%-2.0%, Si 1.0%-1.4%, Mn 0.5%-1.5%, Cr 32%-34%, Ni 1.8%-2.2%, Mo 1.8%-2.2%, Cu 1.1%-1.5%, S≤0.06%, P≤0.1%, V 0.1%-0.5%, PrC2 0.02%-0.1%, and the remainder is Fe.

[0007] According to an embodiment of the present invention, the following components are included in percentage by mass: C 1.64%, Si 1.08%, Mn 1.06%, Cr 33.2%, Ni 2.03%, Mo 1.94%, Cu 1.31%, S ≤ 0.06%, P ≤ 0.1%, V 0.3%, PrC 20.05%, and the remainder is Fe.

[0008] According to a second aspect of the present invention, there is provided a method for preparing a wear-resistant and corrosion-resistant material for a slurry pump, characterized in that it comprises the following steps:

[0009] According to the content of the components, the corresponding weight percentage of the charge is weighed, and the high carbon ferrochrome, low carbon ferrochrome, scrap steel, ferromanganese, ferromolybdenum, ferrosilicon, nickel plate, electrolytic copper and ferrovanadium components are added in proportion to prepare 1 ton of charge;

[0010] Put the weighed metal materials into the medium frequency electric furnace for smelting;

[0011] The liquid is deoxidized and taken out of the furnace when the temperature reaches below 1550℃. Before taking out of the furnace, the furnace is inspected, the composition is adjusted, and the liquid alloy is fully deoxidized to obtain the liquid alloy.

[0012] Before taking out of the furnace, praseodymium carbide powder is scattered in the bag, and after taking out of the furnace, the alloy liquid after modification is obtained;

[0013] The ladle is covered with a slag-aggregating agent and slag-beating, the alloy liquid is allowed to stand in the ladle for a few minutes, and then cast into a pre-prepared sand mold. After naturally cooling to below 200°C, it is boxed and heat-treated to become the required corrosion-resistant and wear-resistant alloy cast iron blank.

[0014] According to an embodiment of the present invention, the pouring process controls the vacuum degree to be no less than 0.04 MPa, and the pouring speed to be no less than 1000 kg / min.

[0015] According to an embodiment of the present invention, the pressure holding time after the pouring is not less than 10 minutes, and the vacuum degree is not less than 0.02 MPa.

[0016] According to an embodiment of the present invention, after the casting is cooled to 200° C., the casting is shaken and cooled to room temperature in air.

[0017] According to an embodiment of the present invention, the casting is heated to 850°C in a heat treatment device, kept warm for 3-4 hours, and then air-cooled for normalizing treatment; then heated to 250°C and kept warm for 4 hours, and then air-cooled for tempering treatment.

[0018] According to an embodiment of the present invention, when the furnace temperature of the casting is lower than 350°C in the heat treatment equipment, the temperature is increased at a rate of 30-40°C per hour, and the temperature is increased at a rate of 40-60°C per hour from 350°C to 700°C. The temperature increase rate in the 700°C to 850°C stage is not higher than 80°C per hour.

[0019] According to the embodiment of the present invention, in the smelting process, a neutral furnace can be used to make slag with quicklime to cover the surface of the molten iron, and the heating temperature of the molten iron should be controlled at 1500-1600°C.

[0020] According to an embodiment of the present invention, before the liquid alloy is taken out of the furnace, a suitable modifier may be added into the bag for modification.

[0021] It can be seen from the above technical scheme that the wear-resistant and corrosion-resistant material for slurry pumps and the preparation method thereof provided by the present invention have the following beneficial effects:

[0022] The present invention discloses a wear-resistant and corrosion-resistant material for slurry pumps and a preparation method thereof. The material can meet the application requirements of non-ferrous mine extraction conditions, especially the corrosion requirements. When abrasion and corrosion are simultaneously applied to the flow material of the pump, the weight loss (loss) of the material will greatly exceed the sum of the abrasion and corrosion alone. The corrosion mainly occurs due to electrochemical factors, while the abrasion mainly occurs due to mechanical effects.

[0023] The material provided by the present invention has a production cost that is about 20% higher than that of the conventional materials mentioned above. In the non-ferrous ore processing process, when PH=1, the service life can reach 2100 hours, which is more than 0.4 times higher than that of conventional materials, meeting the requirements of the equipment maintenance cycle and achieving the equipment design requirements.

[0024] By solving the problem of both corrosion resistance and wear resistance, an alloy containing multiple metals is used to achieve good wear resistance and corrosion resistance, and is practical in strength. Under this condition, praseodymium carbide is added to inhibit electrical corrosion in the alloy, thereby extending its life without affecting its performance. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0026] According to a first aspect of the present invention, there is provided a wear-resistant and corrosion-resistant material for a slurry pump, comprising, by mass: C 1.5%-2.0%, Si 1.0%-1.4%, Mn 0.5%-1.5%, Cr 32%-34%, Ni 1.8%-2.2%, Mo 1.8%-2.2%, Cu 1.1%-1.5%, S≤0.06%, P≤0.1%, V 0.1%-0.5%, PrC2 0.02%-0.1%, and the remainder is Fe.

[0027] 1. Pr (praseodymium) is a rare earth element. Adding it to the alloy can improve its oxidation resistance at lower and higher temperatures, making it more stable during processing and easier to store. It can also improve the mechanical properties and corrosion resistance of the material.

[0028] 2. The addition of Si can effectively reduce the melting temperature of the material and improve its fluidity and wettability. As the silicon content increases, a hypoeutectic region will be formed in the alloy, where the melting point of the material will decrease, and it has good fluidity, wettability and corrosion resistance; by adding silicon and praseodymium carbide to the alloy, both the oxidation resistance and the strength of the material can be guaranteed.

[0029] 3. V can improve the strength and toughness of the material. Vanadium is a strong carbide-forming element. The VC carbide formed has high hardness and high melting point, which can improve the wear resistance and corrosion resistance of the alloy, whether it is the corrosion resistance to strong acid or the resistance to hydrogen corrosion under high temperature and high pressure. At the same time, it improves the hardenability and tempering stability, so that fine-grained martensite is obtained after quenching, and the strength and bending strength of the material are improved.

[0030] 4. Cr and Mo ensure the material's resistance to electrochemical corrosion and intergranular corrosion;

[0031] 5. Ni reduces the critical cooling rate of austenite transformation in cast iron, improves the hardenability and hardening properties of the material, and increases the wear resistance of the material; Mo refines the primary austenite grains, a part of which directly combines with C to form high-hardness carbides, and a part of which dissolves into chromium-carbon compounds, which increases the hardness and strength of the carbides, increases the wear resistance of the material, and improves the material properties. The remaining part is solid-dissolved in austenite and transformation products, strongly delaying the ferrite transformation of austenite, shifting the CCT curve to the right, and improving the wear resistance of the material;

[0032] 6. The solid solubility of Cu in Fe decreases sharply with the decrease of temperature. Cu precipitates from the solid solution and plays a strengthening role. The addition of Cu and Mo can improve the hardenability of the material and increase the wear resistance of the material.

[0033] Example 1

[0034] A wear-resistant and corrosion-resistant material for a slurry pump comprises, by mass, 1.64% C, 1.08% Si, 1.06% Mn, 33.2% Cr, 2.03% Ni, 1.94% Mo, 1.31% Cu, 0.06% S≤0.06%, 0.1% P≤0.1%, 0.3% V, 0.05% PrC2, and the balance Fe.

[0035] Example 2

[0036] A wear-resistant and corrosion-resistant material for a slurry pump comprises, by mass, 1.5% C, 1.0% Si, 0.5% Mn, 32% Cr, 1.8% Ni, 1.8% Mo, 1.1% Cu, ≤0.06% S, ≤0.1% P, 0.1% V, 0.02% PrC2, and the balance Fe.

[0037] Example 3

[0038] A wear-resistant and corrosion-resistant material for a slurry pump comprises, by mass percentage, 1.8% C, 1.3% Si, 0.9% Mn, 33% Cr, 2.0% Ni, 2.0% Mo, 1.4% Cu, ≤0.06% S, ≤0.1% P, 0.2% V, 0.06% PrC2, and the balance Fe.

[0039] Example 4

[0040] A wear-resistant and corrosion-resistant material for a slurry pump comprises, by mass percentage, 2.0% C, 1.4% Si, 1.5% Mn, 34% Cr, 2.2% Ni, 2.2% Mo, 1.5% Cu, ≤0.06% S, ≤0.1% P, 0.5% V, 0.1% PrC, and the balance Fe.

[0041] Comparative Example 1

[0042] The wear-resistant and corrosion-resistant materials with existing components are adopted, which include, by mass percentage, C 1.5, Si 1.5, Mn 0.8, Cr 27.7, Ni 1.7, Mo 1.7, Cu 1.4, S ≤ 0.06%, P ≤ 0.1%, and the balance is Fe.

[0043] Experimental example

[0044] The materials obtained in Examples 1-4 and the materials in Comparative Example 1 were tested for relevant indicators, and their corrosion rates were measured using Cl - The results of H2SO4 solution with a content of 60000PPM, 70℃, and pH=2 are as follows:

[0045] Table 1. Performance tests of Examples 1-4 and Comparative Example 1

[0046] Hardness(HRC) Impact value (KV2 / J) Corrosion rate (mm / a) Example 1 41 8.4 0.43 Example 2 43 7.8 0.49 Example 3 43 8.2 0.44 Example 4 43 8.1 0.42 Comparative Example 1 46 7.4 0.72

[0047] The material provided by the present invention has a production cost that is about 20% higher than that of the conventional materials mentioned above. In the non-ferrous ore processing process, when PH=1, the service life can reach 2100 hours, which is more than 0.4 times higher than that of conventional materials, meeting the requirements of the equipment maintenance cycle and achieving the equipment design requirements.

[0048] By solving the problem of both corrosion resistance and wear resistance, an alloy containing multiple metals is used to achieve good wear resistance and corrosion resistance, and is practical in strength. Under this condition, praseodymium carbide is added to inhibit electrical corrosion in the alloy, thereby extending its life without affecting its performance.

[0049] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wear-resistant and corrosion-resistant material for a slurry pump, characterized in that: In terms of mass percentage, it includes: C 1.5%~2.0%, Si 1.0%~1.4%, Mn 0.5%~1.5%, Cr 32%~34%, Ni 1.8%~2.2%, Mo 1.8%~2.2%, Cu 1.1%~1.5%, S≤0.06%, P≤0.1%, V 0.1%~0.5%, PrC20.02%~0.1%, and the balance is Fe.

2. The wear-resistant and corrosion-resistant material for a slurry pump according to claim 1, characterized in that: In terms of mass percentage, it includes: C 1.64%, Si 1.08%, Mn 1.06%, Cr 33.2%, Ni 2.03%, Mo 1.94%, Cu 1.31%, S ≤ 0.06%, P ≤ 0.1%, V 0.3%, PrC2 0.05%, and the balance is Fe.

3. A method for preparing the wear-resistant and corrosion-resistant material for a slurry pump according to claim 1 or 2, characterized in that: The steps include: According to the content of the components, the corresponding weight percentage of the charge is weighed, and the high carbon ferrochrome, low carbon ferrochrome, scrap steel, ferromanganese, ferromolybdenum, ferrosilicon, nickel plate, electrolytic copper and ferrovanadium components are added in proportion to prepare 1 ton of charge; Put the weighed metal materials into the medium frequency electric furnace for smelting; The liquid is deoxidized and taken out of the furnace when the temperature reaches below 1550℃. Before taking out of the furnace, the furnace is inspected, the composition is adjusted, and the liquid alloy is fully deoxidized to obtain the liquid alloy. Before taking out of the furnace, praseodymium carbide powder is scattered in the bag, and after taking out of the furnace, the alloy liquid after modification is obtained; The ladle is covered with a slag-aggregating agent and slag-beating, the alloy liquid is allowed to stand in the ladle for a few minutes, and then cast into a pre-prepared sand mold. After naturally cooling to below 200°C, it is boxed and heat-treated to become the required corrosion-resistant and wear-resistant alloy cast iron blank.

4. The preparation method according to claim 3, characterized in that: The pouring process controls the vacuum degree to be no less than 0.04 MPa, and the pouring speed to be no less than 1000 kg / min.

5. The preparation method according to claim 3, characterized in that: The pressure holding time after pouring is not less than 10 minutes, and the vacuum degree is not less than 0.02MPa.

6. The preparation method according to claim 3, characterized in that: After the casting has cooled to 200°C, shake the oven and cool it to room temperature in air.

7. The preparation method according to claim 3, characterized in that: The casting is heated to 850° C. in a heat treatment furnace, kept at that temperature for 3-4 hours, and then taken out of the furnace for air cooling and normalizing treatment; then the casting is heated to 250° C. and kept at that temperature for 4 hours, and then taken out of the furnace for air cooling and tempering treatment.

8. The preparation method according to claim 7, characterized in that: The casting is heated at a rate of 30-40°C per hour when the furnace temperature is lower than 350°C in the heat treatment equipment, at a rate of 40-50°C per hour from 350°C to 700°C, and at a rate of no more than 80°C per hour in the 700°C to 850°C stage.

9. The preparation method according to claim 3, characterized in that: In the smelting process, a neutral furnace is used to make slag with quicklime to cover the surface of the molten iron. The heating temperature of the molten iron should be controlled at 1500-1600°C.

10. The preparation method according to claim 3, characterized in that: Before the liquid alloy is taken out of the furnace, a suitable modifier can be added into the bag to perform modification.