Composite hardening process method for axially split pump runner

Abstract

The axially split pump at least comprises an upper pump body, a lower pump body and the flow channel arranged on the upper pump body and the lower pump body in a paired mode, the joint face of the upper pump body and the lower pump body is an axially split face, and a stellite cobalt-based alloy surfacing layer with the set thickness B is arranged on the opening edge, located on the axially split face, of the inner wall of the flow channel in a surfacing mode. The stellite cobalt-based alloy surfacing layer at least extends for a set length L along the inner wall of the runner in the direction far away from the middle opening surface; a tungsten carbide hard alloy layer is further sprayed on the inner wall of the flow channel and covers the stellite cobalt-based alloy surfacing layer, and at least a set distance H is formed between the edge of the tungsten carbide hard alloy layer and the middle opening face.

Description

Technical Field

[0001] The invention relates to the technical field of processing flow channels of a centrifugal pump body, in particular to a composite hardening process method for a center-open pump flow channel. Background Art

[0002] The ash water in coal chemical industry contains a lot of acidic components such as hydrogen sulfide and chloride ions, which causes the split centrifugal pumps used to pump such media to wear quickly and severely, have a short service life and high maintenance costs. To this end, we have developed a process combining supersonic spraying of tungsten carbide and Stellite cobalt-based alloy surfacing for pump body processing and manufacturing through process analysis, innovative design, and experimental verification. This not only solves the wear resistance of the flow channel, but also solves the problems of difficult pump body processing and low production efficiency, thereby developing a centrifugal pump body that meets the complex working conditions of customers. Summary of the invention

[0003] The purpose of the present invention is to provide a composite hardening process method for a split-center pump flow channel, which solves the problem in the prior art that the medium in the working conditions of coal chemical users contains a lot of acidic components such as hydrogen sulfide and chloride ions, resulting in severe wear and short service life of the split-center centrifugal pump, and also solves the problem of difficulty in pump body processing and low production efficiency.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a composite hardening process method for a flow channel of a split pump, wherein the split pump comprises at least an upper pump body 1, a lower pump body 2, and a flow channel 5 arranged in pair on the upper pump body 1 and the lower pump body 2, wherein the joint surface between the upper pump body 1 and the lower pump body 2 is a split surface 3, and a Stellite cobalt-based alloy cladding layer 4 of a set thickness B is clad along the inner wall of the flow channel 5 at the mouth of the split surface 3, and the Stellite cobalt-based alloy cladding layer 4 at least extends a set length L along the inner wall of the flow channel 5 away from the split surface 3; a tungsten carbide cemented carbide layer 7 is also sprayed on the inner wall of the flow channel 5, and the tungsten carbide cemented carbide layer 7 covers the Stellite cobalt-based alloy cladding layer 4 and the edge of the tungsten carbide cemented carbide layer 7 is at least a set distance H from the split surface 3.

[0005] Furthermore, the composite hardening process method for opening the pump flow channel in the present invention further includes the following steps: a. The upper pump body 1 and the lower pump body 2 are cast to form the casting blank surface of the flow channel 5 and the middle open surface 3; b. Mechanically process the middle open surface 3 and the inner wall of the flow channel 5, and pre-process the flow channel 5 at the opening position of the middle working surface 3 according to the size required for the surfacing of the Stellite cobalt-based alloy surfacing layer 4 to form a cavity for accommodating the Stellite cobalt-based alloy surfacing layer 4; c. Pre-treating the inner wall of the flow channel 5 to ensure a smooth transition between the inner wall of the flow channel 5 and the cavity and to ensure that the inner wall of the flow channel 5 is smooth and clean; d. surfacing the Stellite cobalt-based alloy at the cavity to form the Stellite cobalt-based alloy surfacing layer 4; e. After the surfacing is completed, an appearance inspection and a liquid penetration test are performed. If the Stellite cobalt-based alloy surfacing layer 4 is qualified, the next step is performed; f. Grinding the Stellite cobalt-based alloy cladding layer 4 so that the surface of the Stellite cobalt-based alloy cladding layer 4 is smoothly connected to the inner wall of the flow channel 5; h. Fixing and installing a shielding plate 6 on the middle open surface 3; i. Spraying a tungsten carbide hard alloy layer 7 onto the inner wall of the flow channel 5; j. The tungsten carbide hard alloy layer 7 formed in step h is at least inspected for the thickness of the sprayed layer, whether there is any leakage, and the uniformity of the sprayed layer. If it is qualified, it will be transferred to the next step; k. Mechanically process the middle open surface 3 to a set size so as to make the end surface of the Stellite cobalt-based alloy cladding layer 4 flush with the middle open surface 3 and coplanar with the middle open surface 3 .

[0006] Furthermore, the thickness B of the Stellite cobalt-based alloy surfacing layer 4 is 1.5-2.5 mm, the length L is 5-7 mm, and the distance H is 1.8-2.2 mm.

[0007] Furthermore, the step c includes the steps of performing repair actions such as grinding or welding and grinding on casting defects such as pits or scars formed in the flow channel 5 during casting, and removing surface oil stains and rust.

[0008] Furthermore, in the step d, the upper pump body 1 or the lower pump body 2 should be preheated to 150°C to 300°C before the surfacing operation of the Stellite cobalt-based alloy surfacing layer 4 is performed, and the interlayer temperature during surfacing is controlled at 200°C to 350°C.

[0009] Furthermore, between step f and step h, the inner wall of the flow channel 5 is subjected to sandblasting roughening treatment.

[0010] Furthermore, the shielding plate 6 at least includes a plate portion 601 for fixedly connecting to the middle open surface 3 and a rib 602 for extending into the flow channel 5 and matching the distance H, and the number of the ribs 602 matches the number of the flow channels 5 .

[0011] Furthermore, between step j and step k, a polishing treatment is also included on the connection portion between the Stellite cobalt-based alloy cladding layer 4 and the tungsten carbide cemented carbide layer 7 to ensure a smooth transition between the connection portion between the Stellite cobalt-based alloy cladding layer 4 and the tungsten carbide cemented carbide layer 7.

[0012] Furthermore, the tungsten carbide hard alloy layer 7 is prepared by supersonic spraying process.

[0013] Beneficial technical effects of the present invention: the composite hardening process method for the flow channel of a split pump provided by the present invention adopts a process combining supersonic spraying of tungsten carbide cemented carbide and surfacing of Stellite cobalt-based alloy. The flow channel adopts spraying of tungsten carbide cemented carbide, and the flow channel mouth adopts surfacing of Stellite cobalt-based alloy, which significantly enhances the anti-scouring ability of the inner wall of the flow channel of the pump body. Under the harsh temperature and complex particle working conditions of petroleum and coal chemical industry, the service life is increased by at least 2.5 times; the hardness of the Stellite cobalt cemented carbide layer surfacing at the flow channel mouth is HRC43~HRC7, which ensures good machinability while maintaining good wear resistance and scouring resistance relative to the base material of the pump body (upper pump body 1, lower pump body 2), significantly reduces the difficulty of mechanical processing, and can use milling technology to efficiently process the split surface to ensure the roughness and flatness of the split surface, thereby ensuring the sealing performance after the pump body is assembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the top view of the lower pump body of the present application; Figure 2 This is a longitudinal section schematic diagram of the upper pump body and the lower pump body of the present application after being combined; Figure 3 This is a schematic diagram of the positions of the flow channel cladding layer, spray layer and shielding plate of the present application; Figure 4 A three-dimensional diagram of the shielding plate structure of the present application; Figure 5 This is a schematic diagram of the shielding plate installation of this application. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0016] See also Figure 1-5, the composite hardening process method of the flow channel of the split pump is now described. The split pump in the composite hardening process method of the flow channel of the split pump at least includes an upper pump body 1, a lower pump body 2, and a flow channel 5 arranged in pair on the upper pump body 1 and the lower pump body 2. The joint surface of the upper pump body 1 and the lower pump body 2 is a split surface 3. A Stellite cobalt-based alloy cladding layer 4 of a set thickness B is clad on the inner wall of the flow channel 5 at the mouth of the split surface 3. The Stellite cobalt-based alloy cladding layer 4 at least extends a set length L along the inner wall of the flow channel 5 away from the split surface 3; a tungsten carbide cemented carbide layer 7 is also sprayed on the inner wall of the flow channel 5, and the tungsten carbide cemented carbide layer 7 covers the Stellite cobalt-based alloy cladding layer 4 and the tungsten carbide cemented carbide layer 7 The edge has at least a set distance H from the center open surface 3. Preferably, the thickness B of the Stellite cobalt-based alloy cladding layer 4 is 1.5~2.5mm, and the length L is 5~7mm; the distance H is 1.8~2.2mm. The further preferred thickness B is 2mm, and the length L is 6mm; the distance H is 2mm. In this way, when the center open surface 3 is finally precisely machined after the spraying operation is completed, there are only the base material and part of the Stellite cobalt-based alloy cladding layer 4 in the machining area, so it can be ensured that the pump body (upper pump body 1, lower pump body 2) has good machining and cutting performance; here, it can be understood that the above-mentioned dimensional parameters allow normal errors within the process range.

[0017] According to the above-mentioned process method of the present application, the flow channel 5 is surface modified and hardened by a process combining supersonic spraying of tungsten carbide and surfacing of Stellite cobalt-based alloy, that is, the flow channel 5 is sprayed with tungsten carbide, and the flow channel mouth is surfacing with Stellite cobalt-based alloy, which significantly enhances the anti-scouring ability of the inner wall of the pump flow channel 5. Under the harsh temperature and complex particle working conditions of petroleum and coal chemical industry, the service life is increased by at least 2.5 times; the hardness of the Stellite cobalt hard alloy layer surfacing at the flow channel mouth is HRC43~HRC47, Compared with the pump body (upper pump body 1, lower pump body 2), the base material ensures good machinability while maintaining good wear resistance and erosion resistance, significantly reducing the difficulty of mechanical processing. The center open surface can be efficiently processed by milling technology. In addition, the supersonic spray flow channel also has the advantages of fast spraying speed, high production efficiency, profiling, and good coating uniformity. Through the reasonable combination of the two methods, the pump body has extremely high processing efficiency during production and manufacturing, and can effectively ensure the roughness and flatness of the center open surface, thereby ensuring the sealing performance after the pump body is assembled.

[0018] Preferably, the composite hardening process method for opening a pump flow channel in the present invention further includes the following steps: a. The upper pump body 1 and the lower pump body 2 are cast to form the casting blank surface of the flow channel 5 and the middle open surface 3; b. Machining the center opening surface 3 and the inner wall of the flow channel 5, and pre-processing the flow channel 5 at the opening position of the center working surface 3 according to the size required for surfacing of the Stellite cobalt-based alloy surfacing layer 4 to form a cavity for accommodating the Stellite cobalt-based alloy surfacing layer 4, so that after surfacing, while ensuring the thickness of the surfacing layer, the impact on the inner wall of the flow channel 5 is effectively reduced, and the subsequent profiling or grinding amount is reduced; c. Pre-treat the inner wall of the flow channel 5 to ensure a smooth transition between the inner wall of the flow channel 5 and the cavity and to make the inner wall of the flow channel 5 smooth and clean, so as to prepare for surfacing the Stellite cobalt-based alloy and ensure the bonding quality between the surfacing layer and the substrate; d. A Stellite cobalt-based alloy is welded on the cavity to form a Stellite cobalt-based alloy weld layer 4. In this embodiment, non-melting electrode manual tungsten inert gas arc welding (GTAW) is used, the nozzle diameter is Φ10 mm, the tungsten electrode material grade is WCe-20, and the diameter is Φ2.4 mm; the welding wire is ERCoCr-B / Col12 cobalt-based alloy welding wire with a specification of Φ3.2 mm, and the hardness is between HV441.0 and HV459.6. After welding, the hardness is HRC43-HRC47, and the average value is HRC45. In this way, while maintaining good wear resistance and corrosion resistance, it also has excellent machining performance; e. After the surfacing is completed, the appearance inspection and liquid penetration test are carried out. If the Stellite cobalt-based alloy surfacing layer 4 is qualified, it is transferred to the next step; f. Grinding the Stellite cobalt-based alloy cladding layer 4 so that the surface of the Stellite cobalt-based alloy cladding layer 4 is smoothly connected to the inner wall of the flow channel 5; h. A shielding plate 6 is fixedly installed on the middle open surface 3. Here, the shielding plate 6 is made of a high-temperature resistant stainless steel plate, so that when the tungsten carbide hard alloy layer 7 is sprayed, the tungsten carbide hard alloy layer 7 can be prevented from being sprayed on the shielding area, so that the tungsten carbide hard alloy layer 7 is formed in the set area; i. Spraying a tungsten carbide hard alloy layer 7 onto the inner wall of the flow channel 5; j. The tungsten carbide hard alloy layer 7 formed in step h is at least inspected for the thickness of the sprayed layer, whether there is any leakage, and the uniformity of the sprayed layer. If it is qualified, it will be transferred to the next step; k. The center open surface 3 is machined to a set size to make the end surface of the Stellite cobalt-based alloy cladding layer 4 flush with the center open surface 3.

[0019] Preferably, step c includes repairing actions such as grinding or repair welding and grinding on casting defects such as pits or scars formed in the flow channel 5 during casting, and the step of removing surface oil and rust; specifically, the convex defects formed in the flow channel 5 due to casting can be repaired by grinding, and the pits can be repaired by repair welding and then grinding. Impurities such as oil and dirt attached to the surface of the upper pump body 1 or the lower pump body 2 can be removed by cleaning and dried; surface rust should be removed, and usually after cleaning and rust removal, the surface cleanliness should reach SA3 level to ensure the bonding strength between the cladding layer and the spray layer and with the substrate.

[0020] Preferably, in step d, the upper pump body 1 or the lower pump body 2 should be preheated to 150°C to 300°C before the surfacing operation of the Stellite cobalt-based alloy surfacing layer 4 is performed, and the interlayer temperature during surfacing is controlled at 200°C to 350°C to ensure the quality of the surfacing layer and avoid surfacing defects such as cracks.

[0021] Preferably, between step f and step h, the inner wall of the flow channel 5 is also roughened by sandblasting, which effectively improves the bonding strength between the tungsten carbide cemented carbide layer 7 and the substrate. It is understandable that the roughening treatment can also be carried out by chemical treatment or electro-roughening in the prior art.

[0022] Preferably, the shielding plate 6 includes at least one plate portion 601 for fixedly connecting to the center opening surface 3 and a rib 602 for extending into the flow channel 5 and matching the distance H. The number of ribs 602 matches the number of flow channels 5. Thus, when spraying 7 layers of tungsten carbide cemented carbide layer, the barrier effect of the ribs 602 and the plate portion 601 can effectively prevent tungsten carbide from being sprayed onto the center opening surface 3 and the Stellite cobalt-based alloy cladding layer 4 within the distance H, so as to ensure the machining performance of the center opening surface 3.

[0023] Preferably, between step j and step k, the method also includes polishing the connecting portion between the Stellite cobalt-based alloy cladding layer 4 and the tungsten carbide cemented carbide layer 7 to ensure a smooth transition between the connecting portion between the Stellite cobalt-based alloy cladding layer 4 and the tungsten carbide cemented carbide layer 7, thereby ensuring smooth flow of the medium in the split center pump when in use, reducing eddy currents and turbulence, and further reducing vibration of the split center pump when in use.

[0024] Preferably, the tungsten carbide cemented carbide layer 7 is prepared by a supersonic spraying process. In this embodiment, WC-Co, WC-Ni, and Ni60-35%WC nanopowder can be used as spraying materials, and Ni60-35%WC nanopowder is further preferably used as the spraying material; in this embodiment, the powder injection speed during supersonic spraying is 1500-2000m / s, the porosity of the formed coating is less than 0.5%, and the bonding strength is 70MPa. It has the advantages of fast spraying speed, high production efficiency, profiling, and good coating uniformity, and can be fully and effectively sprayed on the inner wall of the flow channel 5; the surface hardness of the tungsten carbide cemented carbide layer 7 is 1750HV, the average hardness of the cladding layer is 1200HV, and the wear resistance is 2.5 times higher than that of the substrate.

[0025] It should be noted that, in this article, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0026] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “top” and “bottom” are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0027] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0028] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite hardening process for a flow channel of a split pump, the split pump comprising at least an upper pump body (1), a lower pump body (2), and a flow channel (5) arranged in pairs on the upper pump body (1) and the lower pump body (2), wherein the joint surface of the upper pump body (1) and the lower pump body (2) is a split surface (3), characterized in that: A Stellite cobalt-based alloy cladding layer (4) of a set thickness B is clad on the inner wall of the flow channel (5) at the edge of the middle opening (3), and the Stellite cobalt-based alloy cladding layer (4) extends at least a set length L along the inner wall of the flow channel (5) in a direction away from the middle opening (3); a tungsten carbide cemented carbide layer (7) is also sprayed on the inner wall of the flow channel (5), and the tungsten carbide cemented carbide layer (7) covers the Stellite cobalt-based alloy cladding layer (4) and the edge of the tungsten carbide cemented carbide layer (7) is at least a set distance H from the middle opening (3).

2. The composite hardening process of a split pump flow channel according to claim 1, characterized in that: The following steps are also included: a. The upper pump body (1) and the lower pump body (2) are cast to form the casting blank surface of the flow channel (5) and the middle open surface (3); b. Mechanically processing the middle open surface (3) and the inner wall of the flow channel (5), and pre-processing the flow channel (5) at the opening position of the middle working surface (3) according to the size required for the surfacing of the Stellite cobalt-based alloy surfacing layer (4) to form a cavity for accommodating the Stellite cobalt-based alloy surfacing layer (4); c. Pre-treating the inner wall of the flow channel (5) so that the inner wall of the flow channel (5) and the cavity have a smooth transition and the inner wall of the flow channel (5) is smooth and clean; d. surfacing the Stellite cobalt-based alloy at the cavity to form the Stellite cobalt-based alloy surfacing layer (4); e. After the cladding is completed, an appearance inspection and a liquid penetrant inspection are performed. If the Stellite cobalt-based alloy cladding layer (4) is qualified, the process proceeds to the next step; f. grinding the Stellite cobalt-based alloy cladding layer (4) so ​​that the surface of the Stellite cobalt-based alloy cladding layer (4) is smoothly connected to the inner wall of the flow channel (5); h. Fixing a shielding plate (6) on the middle open surface (3); i. spraying a tungsten carbide hard alloy layer (7) onto the inner wall of the flow channel (5); j. The tungsten carbide hard alloy layer (7) formed in step h is at least inspected for the thickness of the sprayed layer, whether there is any leakage, and the uniformity of the sprayed layer, and if it is qualified, it is transferred to the next step; k. Mechanically process the middle open surface (3) to a set size so as to make the end surface of the Stellite cobalt-based alloy cladding layer (4) flush with the middle open surface (3).

3. The composite hardening process of a split pump flow channel according to claim 1, characterized in that: The thickness B of the Stellite cobalt-based alloy cladding layer (4) is 1.5-2.5 mm, the length L is 5-7 mm, and the distance H is 1.8-2.2 mm.

4. The composite hardening process of a split pump flow channel according to claim 2, characterized in that: The step c comprises the steps of performing repair actions such as grinding or welding and grinding on casting defects such as pits or scars formed in the flow channel (5) during casting, and removing surface oil stains and rust.

5. The composite hardening process of a split pump flow channel according to claim 2, characterized in that: In the step d, the upper pump body (1) or the lower pump body (2) should be preheated to 150°C to 300°C before the surfacing operation of the Stellite cobalt-based alloy surfacing layer (4) is performed, and the interlayer temperature during surfacing is controlled at 200°C to 350°C.

6. The composite hardening process of a split pump flow channel according to claim 2, characterized in that: Between step f and step h, the inner wall of the flow channel (5) is subjected to sandblasting and roughening treatment.

7. The composite hardening process of a split pump flow channel according to claim 2, characterized in that: The shielding plate (6) comprises at least one plate portion (601) for fixedly connecting to the middle open surface (3) and a retaining edge (602) for extending into the flow channel (5) and matching the distance H, wherein the number of the retaining edges (602) matches the number of the flow channels (5).

8. The composite hardening process of a split pump flow channel according to claim 2, characterized in that: Between step j and step k, a polishing treatment is also included on the connection portion between the Stellite cobalt-based alloy cladding layer (4) and the tungsten carbide hard alloy layer (7), so as to achieve a smooth transition between the connection portion between the Stellite cobalt-based alloy cladding layer (4) and the tungsten carbide hard alloy layer (7).

9. A composite hardening process for a split pump flow channel according to any one of claims 1 to 8, characterized in that: The tungsten carbide hard alloy layer (7) is prepared by a supersonic spraying process.

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