Pump pipe material for high-wear-resistance concrete pump truck and preparation process

Abstract

The invention discloses a high-wear-resistance pump pipe material for a concrete pump truck, the structural design of a pump pipe for the concrete pump truck adopts a composite pipe design, the thickness of an outer pipe is 2mm, the outer pipe is made of Q345 steel, the thickness of an inner pipe is 3mm, the outer pipe is made of wear-resistant cast iron, and the components of the inner pipe material are ground so as to improve the wear resistance of the pump pipe. The invention further provides a preparation process of the pump pipe for the concrete pump truck based on the pump pipe material, the wear-resistant cast iron for the pump pipe inner pipe is prepared by adopting a vacuum melting method or other clean melting methods, is manufactured by adopting a centrifugal casting method, and further reduces the internal stress by adopting heat treatment; the toughness and other properties of the pump pipe for the concrete pump truck are improved, and the service life of the pump pipe for conveying concrete can be remarkably prolonged.

Description

Technical Field

[0001] The present invention relates to the field of metal materials and heat treatment, and in particular to a method for preparing a pump pipe material for a high-wear-resistant concrete pump truck and a casting and heat treatment process thereof. Background Art

[0002] As a common and important building material, concrete plays an important role in the construction field at home and abroad. As a multifunctional and multi-purpose building material, concrete is widely used in various fields such as residential, commercial buildings, and infrastructure. Concrete pump trucks are an important engineering equipment used to transport concrete from concrete mixer trucks to construction sites and implement pouring construction. The main application areas of concrete pump trucks include house construction, bridge construction, tunnel construction, port terminals, etc. They are indispensable equipment for large infrastructure and livelihood projects. In Hong Kong, China, domestic super pump trucks have been used to pump concrete to a building height of more than 400 meters. During use, due to the rapid movement of concrete in the pump pipe of the concrete pump truck, abrasive wear, corrosive wear and friction wear are caused, causing the internal wear of the pump pipe to be very fast. As long as a pump pipe on the concrete pump truck is worn through and fails, all the pump pipes on the entire vehicle need to be replaced at the same time. This is because the cost of stopping construction and replacing the pump pipe is very high, and it is necessary to ensure that all pump pipes on the concrete pump truck have the same or similar service life. The industry has higher and higher requirements for the service life of the pump pipe of the consumable parts of concrete pump trucks. At present, the failure form of the pump pipe is mainly caused by insufficient wear resistance. The service life of domestic pump pipes is only about 70% of that in developed countries such as Europe, the United States, and Japan. Overall, the research and development of high-wear-resistant pump pipe materials and related heat treatment processes is the main development direction.

[0003] The wear resistance of the pump tube determines its service life, and wear resistance depends on two major factors: hardness and toughness. In order to meet the wear resistance index of the pump tube, the pump tube must first be hardened to a certain hardness to ensure high strength. High strength and hardness can ensure that the pump tube has high wear resistance. However, the hardness index cannot be considered alone, because the higher the hardness of steel and cast iron, the greater its brittleness is often, and high brittleness is prone to accelerated wear, leading to failure. According to the friction and wear theory, wear resistance is proportional to hardness and toughness. In order to increase the life of the pump tube, the hardness and toughness indexes should be improved at the same time. There are two measures taken: one is to improve the hardness and toughness through alloying of components, and to distribute highly wear-resistant second phase particles in the material matrix; the second is to optimize the casting and heat treatment process to ensure the comprehensive mechanical performance index. At the same time, the pump tube is required to have high raw material quality, and the content of impurity elements, looseness, bubbles, cracks, non-metallic inclusions, etc. should be reduced as much as possible, and meet the requirements of relevant enterprise, industry and national standards. Therefore, developing high-quality, long-life concrete pump truck pump pipe materials with independent intellectual property rights has significant economic and social benefits, and is of great significance in theory and engineering.

[0004] Concrete pump trucks have been widely used in infrastructure and livelihood projects and other industries. However, as a major manufacturer and user of concrete pump trucks, my country lacks relevant grades of special materials for concrete pump truck pump pipes. Domestically, 65Mn and other spring steels are commonly used after medium-frequency induction quenching and low-temperature tempering. Generally, the average service life is only about 30,000 cubic meters before they can no longer be used. It is urgent to develop a highly wear-resistant material for concrete pump truck pump pipes so that the average service life can reach more than 100,000 cubic meters, which exceeds the life of similar products in developed countries. According to the above situation, a highly wear-resistant concrete pump truck pump pipe material and casting and heat treatment process have been developed. Summary of the invention

[0005] In order to solve the above-mentioned technical problems of pump pipe wear resistance and service life, the present invention provides a high wear-resistant pump pipe material for concrete pump trucks and a preparation process.

[0006] Firstly, a high wear-resistant pump pipe material for concrete pump truck is provided. The pump pipe structure design of the concrete pump truck adopts a composite pipe design. The outer pipe has a thickness of 2 mm and is made of commercial Q345 steel. The inner pipe has a thickness of 3 mm and is made of wear-resistant cast iron developed by itself. The mass percentage of the components of the inner pipe material is as follows: 3.0wt% to 3.6wt% C; 26.0wt% to 30.0wt% Cr; 1.0wt% to 1.5wt% Mo; 1.0wt% to 1.5wt% Ni; 0.7wt% to 1.3wt% La, Ce; 0.7wt% to 1.3wt% Si; 0.5wt% to 1.0wt% Mn; 0.3wt% to 0.6wt% V; 0.1wt% to 0.3wt% Nb; 0.05wt% to 0.15wt% Ti; ≤0.02wt% P; ≤0.02wt% S; ≤0.05wt% Cu; the balance is Fe.

[0007] Secondly, the present invention also provides a preparation process for a high wear-resistant concrete pump truck pump pipe, comprising vacuum smelting, wherein the vacuum smelting comprises the following steps:

[0008] a) mixing the raw materials according to the mass percentage of the elements of the inner tube material to obtain a mixed powder or a block;

[0009] b) smelting the mixed powder or block in a medium frequency electric furnace using a vacuum smelting method at a smelting temperature of 1500° C.-1550° C.;

[0010] c) after smelting, the inner tube is produced by centrifugal casting, the casting temperature is 1430° C.-1480° C., and the wear-resistant cast iron molten metal gradually solidifies during the centrifugal casting process to obtain the wear-resistant cast iron inner tube;

[0011] d) The obtained wear-resistant cast iron inner tube is subjected to low-temperature tempering at 200° C.×4 h in a heat treatment furnace, air-cooled after heat preservation, and the outer surface is polished and finished after tempering.

[0012] Preferably, the smelting temperature in step b) is 1500°C-1550°C.

[0013] Preferably, the casting temperature in step c) is 1430°C-1480°C.

[0014] Preferably, the heat treatment furnace described in step d) is a trolley type furnace, and low-temperature tempering is performed at 200° C.×4 h, followed by air cooling after heat preservation, and the tempering time shall not be shorter than 4 h.

[0015] Finally, a preparation process for a high wear-resistant concrete pump truck pump pipe can be produced by other clean smelting methods besides vacuum smelting, including medium frequency induction furnace and electric arc furnace, characterized in that:

[0016] S1) after smelting molten steel that meets the chemical composition of wear-resistant cast iron elements for concrete pump truck pump pipes in a furnace according to high-grade high-quality cast iron standards, centrifugal casting is performed;

[0017] S2) subjecting the wear-resistant cast iron inner tube of the concrete pump truck pump pipe obtained by centrifugal casting to low-temperature tempering at 200° C.×4 h, heat preservation and then air cooling;

[0018] S3) grinding and finishing the outer surface of the tempered wear-resistant cast iron inner tube;

[0019] S4) the wear-resistant cast iron inner tube obtained in step S3) is compounded with the outer tube and the inner tube on a special device by using a cold-drawn shrink tube technology to obtain a pump tube for a concrete pump truck;

[0020] S5) After the concrete pump truck pump pipe obtained in step S4) is inspected for performance and found to be qualified, a surface coating process is performed.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The concrete pump truck pump pipe structure of the present invention adopts a composite pipe design. The outer pipe is 2 mm thick and is made of commercial Q345 steel. The inner pipe is 3 mm thick and is made of self-developed wear-resistant cast iron. The content of the inner pipe material components is studied and designed, which significantly improves the strength, hardness, corrosion resistance and wear resistance of the pump pipe material matrix.

[0023] 2. After the above-mentioned casting and heat treatment process, the pump pipe for concrete pump truck involved in the present invention has a hardness of ≥56.5HRC, and its service life in related fields is significantly increased from the original 30,000 cubic meters to more than 100,000 cubic meters. It can be used in various fields such as residential, commercial buildings, and infrastructure. It shows excellent performance during use and significantly extends the service life of the pump pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A process flow chart of the preparation of a pump pipe for a concrete pump truck provided by the present invention;

[0025] Figure 2 This is a table of the mass percentage of the elements of the inner tube material provided by the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] See also Figure 1 - Figure 2 The present invention specifically discloses a high wear-resistant pump pipe material for concrete pump trucks. The pump pipe structure design of the concrete pump truck adopts a composite pipe design. The outer pipe has a thickness of 2 mm and is made of commercial Q345 steel. The inner pipe has a thickness of 3 mm and is made of self-developed wear-resistant cast iron. The mass percentage of the inner pipe material components is: 3.0wt% to 3.6wt% C; 26.0wt% to 30.0wt% Cr; 1.0wt% to 1.5wt% Mo; 1.0wt% to 1.5wt% Ni; 0.7wt% to 1.3wt% La, Ce; 0.7wt% to 1.3wt% Si; 0.5wt% to 1.0wt% Mn; 0.3wt% to 0.6wt% V; 0.1wt% to 0.3wt% Nb; 0.05wt% to 0.15wt% Ti; ≤0.02wt% P; ≤0.02wt% S; ≤0.05wt% Cu; the balance is Fe.

[0028] Among them, an appropriate amount of C element in the wear-resistant cast iron is dissolved in austenite and plays a strengthening and hardening role after quenching into martensite, and forms high-hardness Cr23C6 and Cr7C3 particles with Cr element, which are distributed on the martensite matrix, significantly improving the hardness and wear resistance, and ensuring the strength, hardness and wear resistance of the pump pipe material matrix; the large amount of Cr element added not only generates Cr23C6 and Cr7C3 particles with C element, improving the hardness and wear resistance, but also makes the C curve significantly shift to the right, improving the hardenability; in the centrifugal casting air cooling process, it can be quenched to form a martensitic structure, further improving the strength and hardness, which is beneficial to improving wear resistance, especially the addition of a large amount of Cr element significantly improves the corrosion resistance of the material and improves the corrosion and wear resistance; the addition of Mo element improves the material's ability to resist pitting corrosion and further improves the corrosion and wear resistance.

[0029] In addition, Mo2C and MoC nanoparticles can be formed to further improve strength, hardness and wear resistance. Since the material contains a large number of Cr23C6 and Cr7C3 particles, it is easy to increase the brittleness of the material. Therefore, Ni is added to improve the toughness of the matrix. Adding La and Ce mixed rare earth elements is beneficial to purifying the material and further improving the material performance. Si and Mn elements can effectively play a solid solution strengthening effect and are low in cost. The addition of both is beneficial to strengthening the material matrix. V and Nb elements are mainly used. Adding V, Nb and Ti elements is beneficial to refining the grain size. According to Hall-Petc h formula, grain refinement can improve strength and hardness, while plasticity is also improved simultaneously. Toughness depends on strength and plasticity. When strength and plasticity are improved at the same time, toughness is greatly improved. Refined grains are beneficial to improving material strength and toughness. The added V, Nb, and Ti elements can also precipitate nanoscale VC, NbC, TiC and other second phase strengthening materials that are coherent with the matrix. Due to the large amount of C and alloy elements added, the Ms point is reduced, so that austenite structure still exists in the wear-resistant cast iron structure. Although the hardness of austenite is low, which is not conducive to improving wear resistance, austenite is a soft and tough phase, which is beneficial to reducing brittleness and improving toughness.

[0030] The present invention also provides a preparation process of the wear-resistant cast iron inner tube: vacuum smelting or other clean smelting methods are used for smelting, and centrifugal casting is used for forming. In order to further understand the present invention, the wear-resistant cast iron inner tube provided by the present invention is described in detail below in conjunction with the embodiments, and the protection scope of the present invention is not limited by the following embodiments.

[0031] Embodiment 1:

[0032] (1) Wear-resistant cast iron element content: 3.53wt% C; 29.6wt% Cr; 1.12wt% Mo; 1.25wt% Ni; 0.91wt% La, Ce; 1.18wt% Si; 0.75wt% Mn; 0.51wt% V; 0.18wt% Nb; 0.08wt% Ti; 0.018wt% P; 0.017wt% S; 0.02wt% Cu; the balance is Fe; a mixed powder or block is obtained;

[0033] (2) melting the mixed powder or block obtained in step (1) in a vacuum electric furnace at a smelting temperature of 1500° C. to 1550° C.;

[0034] (3) After smelting, the inner tube is produced by centrifugal casting, the casting temperature is 1430° C.-1480° C., and the wear-resistant cast iron molten metal gradually solidifies during the centrifugal casting process to obtain the wear-resistant cast iron inner tube;

[0035] (4) subjecting the wear-resistant cast iron inner tube obtained in step (3) to low-temperature tempering at 200° C. for 4 h in a trolley furnace, and then air-cooling after heat preservation;

[0036] (5) grinding and finishing the outer surface of the wear-resistant cast iron inner tube obtained in step (4);

[0037] (6) The wear-resistant cast iron inner tube obtained in step (5) is subjected to cold drawing shrinkage technology to compound the outer tube and the inner tube on a special device, and then a pump tube for a concrete pump truck is obtained.

[0038] The wear-resistant cast iron inner tube prepared according to the above method was subjected to hardness testing and the installed life assessment of the pump tube for concrete pump truck was carried out. The results are shown in Table 1.

[0039] Embodiment 2:

[0040] (1) Wear-resistant cast iron element content: 3.17wt% C; 26.3wt% Cr; 1.27wt% Mo; 1.13wt% Ni; 1.08wt% La, Ce; 0.93wt% Si; 0.73wt% Mn; 0.35wt% V; 0.23wt% Nb; 0.09wt% Ti; 0.019wt% P; 0.018wt% S; 0.01wt% Cu; the balance is Fe; a mixed powder or block is obtained;

[0041] (2) melting the mixed powder or block obtained in step (1) in a vacuum electric furnace at a smelting temperature of 1500° C. to 1550° C.;

[0042] (3) After smelting, the inner tube is produced by centrifugal casting, the casting temperature is 1430° C.-1480° C., and the wear-resistant cast iron molten metal gradually solidifies during the centrifugal casting process to obtain the wear-resistant cast iron inner tube;

[0043] (4) subjecting the wear-resistant cast iron inner tube obtained in step (3) to low-temperature tempering at 200° C. for 4 h in a trolley furnace, and then air-cooling after heat preservation;

[0044] (5) grinding and finishing the outer surface of the wear-resistant cast iron inner tube obtained in step (4);

[0045] (6) The wear-resistant cast iron inner tube obtained in step (5) is subjected to cold drawing shrinkage technology to compound the outer tube and the inner tube on a special device, and then a pump tube for a concrete pump truck is obtained.

[0046] The wear-resistant cast iron inner tube prepared according to the above method was subjected to hardness testing and the installed life assessment of the pump tube for concrete pump truck was carried out. The results are shown in Table 1.

[0047] Embodiment 3:

[0048] (1) Wear-resistant cast iron element content: 3.24wt% C; 27.1wt% Cr; 1.23wt% Mo; 1.37wt% Ni; 0.79wt% La, Ce; 1.27wt% Si; 0.83wt% Mn; 0.42wt% V; 0.17wt% Nb; 0.11wt% Ti; 0.018wt% P; 0.018wt% S; 0.01wt% Cu; the balance is Fe; a mixed powder or block is obtained;

[0049] (2) melting the mixed powder or block obtained in step (1) in a vacuum electric furnace at a smelting temperature of 1500° C. to 1550° C.;

[0050] (3) After smelting, the inner tube is produced by centrifugal casting, the casting temperature is 1430° C.-1480° C., and the wear-resistant cast iron molten metal gradually solidifies during the centrifugal casting process to obtain the wear-resistant cast iron inner tube;

[0051] (4) subjecting the wear-resistant cast iron inner tube obtained in step (3) to low-temperature tempering at 200° C. for 4 h in a trolley furnace, and then air-cooling after heat preservation;

[0052] (5) grinding and finishing the outer surface of the wear-resistant cast iron inner tube obtained in step (4);

[0053] (6) The wear-resistant cast iron inner tube obtained in step (5) is subjected to cold drawing shrinkage technology to compound the outer tube and the inner tube on a special device, and then a pump tube for a concrete pump truck is obtained.

[0054] The wear-resistant cast iron inner tube prepared according to the above method was subjected to hardness testing and the installed life assessment of the pump tube for concrete pump truck was carried out. The results are shown in Table 1.

[0055] Embodiment 4:

[0056] (1) Wear-resistant cast iron element content: 3.37wt% C; 27.9wt% Cr; 1.19wt% Mo; 1.35wt% Ni; 1.27wt% La, Ce; 1.13wt% Si; 0.83wt% Mn; 0.43wt% V; 0.19wt% Nb; 0.07wt% Ti; 0.019wt% P; 0.019wt% S; 0.02wt% Cu; the balance is Fe; a mixed powder or block is obtained;

[0057] (2) melting the mixed powder or block obtained in step (1) in a vacuum electric furnace at a smelting temperature of 1500° C. to 1550° C.;

[0058] (3) After smelting, the inner tube is produced by centrifugal casting, the casting temperature is 1430° C.-1480° C., and the wear-resistant cast iron molten metal gradually solidifies during the centrifugal casting process to obtain the wear-resistant cast iron inner tube;

[0059] (4) subjecting the wear-resistant cast iron inner tube obtained in step (3) to low-temperature tempering at 200° C. for 4 h in a trolley furnace, and then air-cooling after heat preservation;

[0060] (5) grinding and finishing the outer surface of the wear-resistant cast iron inner tube obtained in step (4);

[0061] (6) The wear-resistant cast iron inner tube obtained in step (5) is subjected to cold drawing shrinkage technology to compound the outer tube and the inner tube on a special device, and then a pump tube for a concrete pump truck is obtained.

[0062] The wear-resistant cast iron inner tube prepared according to the above method was subjected to hardness testing and the installed life assessment of the pump tube for concrete pump truck was carried out. The results are shown in Table 1.

[0063] Embodiment 5:

[0064] (1) Wear-resistant cast iron element content: 3.48wt% C; 28.7wt% Cr; 1.42wt% Mo; 1.37wt% Ni; 1.04wt% La, Ce; 1.14wt% Si; 0.82wt% Mn; 0.53wt% V; 0.17wt% Nb; 0.06wt% Ti; 0.019wt% P; 0.018wt% S; 0.01wt% Cu; the balance is Fe, to obtain a mixed powder or block;

[0065] (2) melting the mixed powder or block obtained in step (1) in a vacuum electric furnace at a smelting temperature of 1500° C. to 1550° C.;

[0066] (3) After smelting, the inner tube is produced by centrifugal casting, the casting temperature is 1430° C.-1480° C., and the wear-resistant cast iron molten metal gradually solidifies during the centrifugal casting process to obtain the wear-resistant cast iron inner tube;

[0067] (4) subjecting the wear-resistant cast iron inner tube obtained in step (3) to low-temperature tempering at 200° C. for 4 h in a trolley furnace, and then air-cooling after heat preservation;

[0068] (5) The outer surface of the wear-resistant cast iron inner tube obtained in step (4) is polished and finished.

[0069] (6) The wear-resistant cast iron inner tube obtained in step (5) is subjected to cold drawing shrinkage technology to compound the outer tube and the inner tube on a special device, and then a pump tube for a concrete pump truck is obtained.

[0070] The wear-resistant cast iron inner tube prepared according to the above method was subjected to hardness testing and the installed life assessment of the pump tube for concrete pump truck was carried out. The results are shown in Table 1.

[0071] Embodiment 6:

[0072] (1) Wear-resistant cast iron element content: 3.56wt% C; 29.1wt% Cr; 1.27wt% Mo; 1.19wt% Ni; 1.13wt% La, Ce; 1.21wt% Si; 0.81wt% Mn; 0.46wt% V; 0.23wt% Nb; 0.07wt% Ti; 0.018wt% P; 0.019wt% S; 0.01wt% Cu; the balance is Fe, to obtain a mixed powder or block;

[0073] (2) melting the mixed powder or block obtained in step (1) in a vacuum electric furnace at a smelting temperature of 1500° C. to 1550° C.;

[0074] (3) After smelting, the inner tube is produced by centrifugal casting, the casting temperature is 1430° C.-1480° C., and the wear-resistant cast iron molten metal gradually solidifies during the centrifugal casting process to obtain the wear-resistant cast iron inner tube;

[0075] (4) subjecting the wear-resistant cast iron inner tube obtained in step (3) to low-temperature tempering at 200° C. for 4 h in a trolley furnace, and then air-cooling after heat preservation;

[0076] (5) grinding and finishing the outer surface of the wear-resistant cast iron inner tube obtained in step (4);

[0077] (6) The wear-resistant cast iron inner tube obtained in step (5) is subjected to cold drawing shrinkage technology to compound the outer tube and the inner tube on a special device, and then a pump tube for a concrete pump truck is obtained.

[0078] The wear-resistant cast iron inner tube prepared according to the above method was subjected to hardness testing and the installed life assessment of the pump tube for concrete pump truck was carried out. The results are shown in Table 1.

[0079]

[0080] Table 1 Performance test results of concrete pump truck pump pipe prepared in Example

[0081] It can be seen from Table 1 that the pump pipe for concrete pump trucks provided by the present invention has high wear resistance and a service life of more than 100,000 cubic meters, and is suitable for the manufacture of pump pipes for concrete pump trucks.

[0082] In summary, the high wear-resistant concrete pump truck pump pipe material and casting and heat treatment process of the present invention are applied to various fields such as residential, commercial buildings, infrastructure, etc., and show excellent performance during use, significantly extending the service life of the pump pipe. Experiments have shown that the concrete pump truck pump pipe of the present invention has a hardness of ≥56.5HRC after being treated by the above casting and heat treatment process, and its service life in related fields is significantly increased from the original 30,000 cubic meters to more than 100,000 cubic meters.

[0083] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

Claims

1. A highly wear-resistant pump pipe material for a concrete pump truck, characterized in that: The pump pipe structure design for concrete pump trucks adopts a composite pipe design. The outer pipe is 2mm thick and is made of commercial Q345 steel. The inner pipe is 3mm thick and is made of self-developed wear-resistant cast iron. The mass percentage of the inner pipe material components is: 3.0 wt% to 3.6 wt% C; 26.0wt%~30.0wt%Cr; 1.0wt%~1.5wt%Mo; 1.0wt%~1.5wt%Ni; 0.7wt%~1.3wt%La,Ce; 0.7wt%~1.3wt%Si; 0.5wt%~1.0wt%Mn; 0.3wt%~0.6wt%V; 0.1wt%~0.3wt%Nb; 0.05wt%~0.15wt%Ti; ≤0.02wt%P; ≤0.02wt%S; ≤0.05wt%Cu; The balance is Fe.

2. A process for preparing a high wear-resistant concrete pump truck pump pipe as claimed in claim 1, comprising vacuum smelting, characterized in that: The vacuum smelting comprises the following steps: a) mixing the following raw materials to obtain a mixed powder or block, wherein the wear-resistant cast iron element mass percentage is: 3.0wt%-3.6wt% C; 26.0wt%-30.0wt% Cr; 1.0wt%-1.5wt% Mo; 1.0wt%-1.5wt% Ni; 0.7wt%-1.3wt% La, Ce; 0.7wt%-1.3wt% Si; 0.5wt%-1.0wt% Mn; 0.3wt%-0.6wt% V; 0.1wt%-0.3wt% Nb; 0.05wt%-0.15wt% Ti; ≤0.02wt% P; ≤0.02wt% S; ≤0.05wt% Cu; the balance is Fe; b) smelting the mixed powder or block in a medium frequency electric furnace using a vacuum smelting method at a smelting temperature of 1500° C.-1550° C.; c) after smelting, the inner tube is produced by centrifugal casting, the casting temperature is 1430° C.-1480° C., and the wear-resistant cast iron molten metal gradually solidifies during the centrifugal casting process to obtain the wear-resistant cast iron inner tube; d) The obtained wear-resistant cast iron inner tube is subjected to low-temperature tempering at 200°C × 4h in a heat treatment furnace, air-cooled after heat preservation, and polished and finished on the outer surface after tempering.

3. The preparation process of a high wear-resistant concrete pump truck pump pipe according to claim 2, characterized in that: After the wear-resistant cast iron inner tube is made in step c), low-temperature tempering at 200° C.×4 h is performed. Due to the high content of alloy elements, the wear-resistant cast iron has high hardenability. Part of the martensitic structure has been formed during the air cooling process of centrifugal casting. The low-temperature tempering at 200° C.×4 h stabilizes the structure and transforms the quenched martensite into tempered martensite, which is beneficial to reducing the structural stress, reducing the brittleness and improving the toughness. On the other hand, it is also beneficial to reduce the casting thermal stress and reduce the tendency of deformation cracking.

4. The process for preparing a high wear-resistant concrete pump truck pump pipe according to claim 2, characterized in that: In step d), the outer surface is polished and finished to prepare for the subsequent composite manufacturing of the outer tube and the inner tube.

5. The process for preparing a high wear-resistant concrete pump truck pump pipe according to claim 2, characterized in that: After step d), the outer tube and the inner tube are compounded on special equipment using cold-drawn shrink tube technology, and then a pump tube for a concrete pump truck is obtained.

6. According to the preparation process of a highly wear-resistant pump pipe for a concrete pump truck as described in claim 2, after the pump pipe for a concrete pump truck is obtained in subsequent production and tested for performance, a surface coating process is performed, which is used for rust prevention on the one hand and has an aesthetic effect on the other hand.

7. The process for preparing a high wear-resistant concrete pump truck pump pipe according to claim 2, characterized in that: During the compounding and handling process of the concrete pump truck pump pipe described in step d), no surface defects such as scratches are allowed.

8. The preparation process of a high wear-resistant concrete pump truck pump pipe according to claim 2 can be produced by other clean smelting methods besides vacuum smelting, including medium frequency induction furnace and electric arc furnace, characterized in that: S1) The chemical composition of the wear-resistant cast iron element (mass percentage: 3.0wt% to 3.6wt% C; 26.0wt% to 30.0wt% Cr; 1.0wt% ~ 1.5wt% Mo; 1.0wt% ~ 1.5wt% Ni; 0.7wt% ~ 1.3wt% La, Ce; 0.7wt% ~ 1.3wt% Si; 0.5wt% ~ 1.0wt% Mn; 0.3wt% ~ 0.6wt% V; 0.1wt%~0.3wt%Nb; 0.05wt%~0.15wt%Ti; ≤0.02wt% P; ≤0.02wt% S; ≤0.05wt% Cu; the balance is Fe;) molten steel is smelted in a furnace according to high-grade high-quality cast iron standards and then centrifugally cast; S2) subjecting the wear-resistant cast iron inner tube of the concrete pump truck pump pipe obtained by centrifugal casting to low-temperature tempering at 200° C.×4 h, heat preservation and then air cooling; S3) grinding and finishing the outer surface of the tempered wear-resistant cast iron inner tube; S4) the wear-resistant cast iron inner tube obtained in step S3) is compounded with the outer tube and the inner tube on a special device by using a cold-drawn shrink tube technology to obtain a pump tube for a concrete pump truck; S5) After the concrete pump truck pump pipe obtained in step S4) is inspected for performance and found to be qualified, a surface coating process is performed.

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