A pump truck eyewear plate wear ring

Abstract

The present application relates to a kind of pump truck eyeglass plate wear-resistant ring, the wear-resistant ring is composed of two rings, upper ring is the high-chromium high-tungsten powder metallurgy high-speed steel pressure ring with certain taper, lower ring is high-chromium cast iron ring;The composition of the high-chromium high-tungsten powder metallurgy high-speed steel is: Cr: 18-28%, W: 10-15%, Mo: 8-12%, V: 4-6%, Ce: 0-2.5%, Fe balance (mass fraction %).The present application uses powder metallurgy process near net shape to prepare high-chromium high-tungsten powder metallurgy high-speed steel pressure ring, hardness is as high as 68-70HRC, impact toughness reaches 20-25J / cm 2 Make eyeglass plate wear-resistant ring have high impact resistance and wear resistance, can effectively improve the problem such as the wear resistance of the previous pump truck wear-resistant ring inner wall material surfacing high-chromium cast iron, hard alloy is easy to impact collapse etc.;And the taper structure of upper ring can slow down the degree of impact and wear of the weak place of inner wall periphery, prolong the service life of eyeglass plate wear-resistant ring, reduce the use cost.

Description

Technical Field

[0001] This invention relates to the field of spectacle plate technology for pump trucks, and specifically to a wear-resistant ring for a spectacle plate on a pump truck. Background Technology

[0002] The spectacle plate is a wear-resistant component of a concrete pump truck and a key vulnerable part. It typically has two openings, each connecting to the conveyor bar. During pumping, the spectacle plate and the cutting ring reciprocate in a cutting motion to achieve material suction and delivery. It requires not only good wear resistance but also a certain degree of impact and fatigue resistance. Currently, most spectacle plates in the pumping industry are constructed by brazing a steel billet substrate with cemented carbide, and the inner hole is constructed using high-strength wear-resistant welding material. During pumping, the substrate and the gaps between the brazed sections have poor wear resistance. After wear, the exposed cemented carbide is easily damaged by abrasive impacts. The weld overlay layer in the inner hole is prone to cracking and chipping due to internal stress. Furthermore, the area between the spectacle plate and the cutting ring traps mud and sand, and the outer edge of the inner hole experiences frequent and greater friction and impact forces, making it susceptible to abrasive impacts and wear—currently the weakest point of the spectacle plate.

[0003] High-chromium alloy cast iron with weld overlay has an average hardness of around 62 HRC, exhibiting high wear resistance, good machinability, and low production cost. However, its poor thermal conductivity makes it prone to cracking and chipping during use due to the high internal stress of the weld overlay layer, severely impacting the lifespan of the spectacle plate. On the other hand, cemented carbide can achieve a hardness of over 70 HRC and has excellent wear resistance, but its poor bending strength and toughness make it unable to withstand the strong impact during pumping, also affecting the lifespan of the spectacle plate. Furthermore, cemented carbide is also very expensive. Currently, many technologies are disclosed in the existing technology to improve the wear resistance and reduce the cost of use of wear-resistant rings. However, the materials used for inner hole wear-resistant rings are basically wear-resistant cast iron or hard alloy, with only corresponding improvements in specific structure and process. For example, Chinese patent CN201711480337.7 discloses an impact-resistant spectacle plate and cutting ring for concrete pumps, which has a wear-resistant layer on the wall of the opening formed by wear-resistant material welded to the wall of the opening. CN201810550477.5 discloses a spectacle plate for concrete conveying pumps, in which the wear-resistant sleeve is composed of conical through holes. These structural improvements have solved the wear resistance problem of spectacle plates to a certain extent, and have also improved the service life and reduced the cost to a certain extent. However, there is still much room for improvement. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wear-resistant ring for a pump truck spectacle plate.

[0005] This invention is achieved through the following technical solution:

[0006] A wear-resistant ring for a pump truck spectacle plate is characterized in that the wear-resistant ring consists of two rings, an upper ring and a lower ring. The upper ring is a high-chromium, high-tungsten powder metallurgy high-speed steel pressure ring with a certain taper, and its composition is: Cr: 18-28%, W: 10-15%, Mo: 8-12%, V: 4-6%, Ce: 0-2.5%, and Fe balance; the lower ring is a high-chromium cast iron ring.

[0007] The preparation method of the above-mentioned spectacle plate wear-resistant ring includes the following steps:

[0008] Step 1: Weigh the raw material powders according to the above proportions and mix them.

[0009] Step 2: Place the mixed powder obtained in Step 1 into a ring mold for near-net-shape forming and pressing. The pressing pressure is 300-500 MPa to obtain a compact.

[0010] Step 3: Sinter the pressed blank obtained in Step 2 in a vacuum sintering furnace at a maximum sintering temperature of 1250℃ for 2 hours.

[0011] Step 4: Perform vacuum heat treatment on the sintered billet obtained in Step 3. The quenching process is to hold at 1230℃ for 30 minutes and then air cool. The tempering process is to hold at 560℃ for 1.5 hours and then temper three times.

[0012] Preferably, the lower ring of the spectacle plate wear-resistant ring is prepared by centrifugal casting and has a hardness of 62HRC after heat treatment.

[0013] Preferably, the wear-resistant ring of the spectacle plate adopts a hot-setting followed by cold-setting method; that is, first, an interference fit is made, the spectacle plate is heated, and then a powder metallurgy high-speed steel ring is interference-fitted in. After cooling to room temperature, the high-chromium cast iron ring is cooled to -150°C and interference-fitted into the inner hole of the spectacle plate.

[0014] The wear-resistant ring of the spectacle plate prepared above is made of high-chromium, high-tungsten powder metallurgy high-speed steel pressure ring, with a hardness of up to 68-70 HRC and an impact toughness of 20-25 J / cm. 2 This gives the spectacle plate wear ring high impact resistance and wear resistance, effectively improving the problems of high-chromium cast iron being poorly wear-resistant and hard alloy being prone to impact chipping in the inner wall material of previous pump truck wear rings; in addition, the tapered structure of the upper ring can reduce the impact and wear on the weak parts of the inner wall, extend the service life of the spectacle plate wear ring and reduce the cost of use.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. The upper ring of the spectacle plate wear ring of the present invention is made of high-chromium and high-tungsten powder metallurgy high-speed steel pressure ring, which has high hardness (68-70HRC) and toughness, giving the spectacle plate wear ring high impact resistance and wear resistance. It can effectively improve the problems of high-chromium cast iron overlay, which is not wear-resistant, and hard alloy, which is prone to impact chipping in the inner wall material of the previous pump truck wear ring. In addition, the tapered structure of the upper ring can reduce the impact and wear on the weak parts of the inner wall, extend the service life of the spectacle plate wear ring and reduce the cost of use.

[0017] 2. The wear-resistant ring of the spectacle plate adopts a combination method of hot setting followed by cold setting. This method can avoid the softening of high-speed steel due to overheating during welding, give full play to the advantage of high-chromium cast iron rings that are not prone to cracking, and also avoid phenomena such as the upper ring falling off or shifting due to secondary heating. It has the advantages of low energy consumption and less oxidation.

[0018] 3. Near-net-shape forming pressing can significantly reduce production costs. At the same time, the resulting pressing ring has advantages such as uniform and fine structure, no ledeburite and component segregation, low impurity content, and short process flow. It can effectively solve the problems of high impurity content, high internal stress, and serious pollution in the previous welding process. Attached Figure Description

[0019] Figure 1 The schematic diagram of the wear-resistant ring for the spectacle plate pump truck is shown in the figure. The markings are: Upper ring-1, Lower ring-2, Inner hole-3.

[0020] Figure 2 SEM image of the microstructure of the high-chromium, high-tungsten powder metallurgy high-speed steel pressure ring in Example 1.

[0021] Figure 3 SEM image of the microstructure of the high-chromium, high-tungsten powder metallurgy high-speed steel pressure ring in Example 2.

[0022] Figure 4 SEM image of the microstructure of the high-chromium, high-tungsten powder metallurgy high-speed steel pressure ring in Example 3. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of this invention, the invention will be further described in detail below with reference to the accompanying drawings and specific examples. It should be noted that the following embodiments are only used to more clearly illustrate the technical solution of this invention and should not be used to limit the scope of protection of this invention.

[0024] Example 1

[0025] 1. Mix 20% Cr powder, 12% W powder, 8% Mo powder, 5% V powder, 0.8% Ce powder, and the balance Fe powder;

[0026] 2. Place the mixed powder obtained in step 1 into a ring mold for near-net-shape forming and pressing. The pressing pressure is 400 MPa to obtain a compact.

[0027] 3. The pressed blank obtained in step 2 is sintered in a vacuum sintering furnace at a maximum sintering temperature of 1250℃ for 2 hours.

[0028] 4. The sintered billet obtained in step 3 is subjected to vacuum heat treatment. The quenching process is to hold at 1230℃ for 30 minutes and then air cool. The tempering process is to hold at 560℃ for 1.5 hours and then temper three times.

[0029] Experimental results show that the hardness of high-chromium, high-tungsten powder metallurgy high-speed steel is 68.3 HRC.

[0030] Example 2

[0031] 1. Mix 25% Cr powder, 15% W powder, 10% Mo powder, 5% V powder, and the balance Fe powder;

[0032] 2. Place the mixed powder obtained in step 1 into a ring mold for near-net-shape forming and pressing. The pressing pressure is 450 MPa to obtain a compact.

[0033] 3. The pressed blank obtained in step 2 is sintered in a vacuum sintering furnace at a maximum sintering temperature of 1250℃ for 2 hours.

[0034] 4. The sintered billet obtained in step 3 is subjected to vacuum heat treatment. The quenching process is to hold at 1230℃ for 30 minutes and then air cool. The tempering process is to hold at 560℃ for 1.5 hours and then temper three times.

[0035] Experimental results show that the hardness of high-chromium, high-tungsten powder metallurgy high-speed steel is 68.9 HRC.

[0036] Example 3

[0037] 1. Mix 28% Cr powder, 15% W powder, 8% Mo powder, 4% V powder, 1.2% Ce powder, and the balance Fe powder;

[0038] 2. Place the mixed powder obtained in step 1 into a ring mold for near-net-shape forming and pressing. The pressing pressure is 420 MPa to obtain a compact.

[0039] 3. The pressed blank obtained in step 2 is sintered in a vacuum sintering furnace at a maximum sintering temperature of 1250℃ for 2 hours.

[0040] 4. The sintered billet obtained in step 3 was subjected to vacuum heat treatment. The quenching process involved holding at 1230℃ for 30 minutes and then air cooling, while the tempering process involved holding at 560℃ for 1.5 hours, with the tempering process repeated three times. Experimental results showed that the hardness of the high-chromium, high-tungsten powder metallurgy high-speed steel was 69.8 HRC.

Claims

1. A pump truck eyewear plate wear ring characterized by, The wear-resistant ring is composed of two rings, the upper ring is a high-chromium high-tungsten powder metallurgy high-speed steel press ring with a certain taper, the composition is as follows in percentage by mass: Cr: 18-28%, W: 10-15%, Mo: 8-12%, V: 4-6%, Ce: 0-2.5%, Fe: balance; the lower ring is a high-chromium cast iron ring; the high-chromium high-tungsten powder metallurgy high-speed steel press ring has a hardness of 68-70 HRC and an impact toughness of 20-25 J / cm 2 .

2. The pump temple lens plate wear ring of claim 1, wherein, The preparation method of the upper ring comprises the following steps: Step 1, the raw material powder is weighed according to the component ratio, and mixed; Step 2, the mixed powder obtained in step 1 is placed in a circular ring mold for near-net forming compression, and the compression pressure is 300-500 MPa, to obtain a compact; Step 3, the compact obtained in step 2 is sintered in a vacuum sintering furnace, and the highest sintering temperature is 1250 DEG C, and the sintering time is 2 h; Step 4, the sintered compact obtained in step 3 is subjected to vacuum heat treatment, the quenching process is 1230 DEG C for 30 min air cooling, and the tempering process is 560 DEG C for 1.5 h, and the tempering is performed three times.

3. The pump temple lens plate wear ring of claim 1, wherein, The lower ring is prepared by centrifugal casting, and the hardness after heat treatment is 62 HRC.

4. The pump temple lens plate wear ring of claim 1, wherein, The spectacle plate wear-resistant ring adopts a matching mode of first hot insertion and then cold insertion; that is, first interference fit, heat the spectacle plate, then interference fit and insert the powder metallurgy high-speed steel ring, cool to room temperature, then cool the high-chromium cast iron ring to-150 DEG C, and interference fit and insert into the inner hole of the spectacle plate.

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