A high-speed grinding method for single-crystal high-temperature alloy turbine working blades

Abstract

The present invention provides a high-speed grinding method for a single crystal high-temperature alloy turbine blade. According to the minimum high-speed grinding wheel linear speed and the minimum diameter of the grinding wheel, the minimum rotation speed of the grinding wheel shaft is obtained based on the linear speed formula; based on the ratio of the roller to the grinding wheel linear speed and the minimum diameter of the roller shaft, the minimum value of the roller linear speed is obtained, and the minimum rotation speed of the roller is obtained; according to the abrasive parameters and the minimum rotation speed of the grinding wheel shaft, based on the single abrasive grain cutting thickness calculation formula, the initial grinding wheel feed speed is obtained, and multiple tests are carried out based on this and the minimum rotation speed of the roller; the processed single crystal blade is inspected through surface quality detection, the initial grinding wheel feed speed is adjusted, and the final grinding wheel feed speed is obtained. The present application adopts a high-speed grinding process for single crystal blades, and through equipment selection, high-speed grinding wheel selection, processing parameter formulation and surface quality evaluation, the grinding efficiency and surface quality of the single crystal material turbine blade are improved. The grinding efficiency of the present application is improved by more than three times, the occurrence of surface ablation of parts is avoided, and the processing quality of parts is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aeroengine and gas turbine machining, and in particular relates to a high-speed grinding method for single-crystal high-temperature alloy turbine working blades. Background Art

[0002] In the field of aero-engine and gas turbine processing, turbine blades, as core components of the engine turbine rotor, are exposed to harsh environments of high temperature, high pressure, and high speed for a long time, which places high demands on the performance of the blades. Single crystal high-temperature alloys have the advantages of high temperature resistance, corrosion resistance, and good fatigue resistance, and have become the preferred material for new large-thrust engine turbine blades.

[0003] At present, single crystal turbine blades are processed by grinding. At present, the grinding line speed is 18-22m / s, the feed speed is 100-300mm / min, and the grinding efficiency is low, especially in the tenon part of the casting. The tenon part generally adopts a trapezoidal structure, and the processing allowance is large, generally more than 5mm. The processing time of a single blade tenon is about 45min. The existing grinding process is inefficient and cannot meet the processing needs of large quantities of blades. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a method for high-speed grinding of single-crystal high-temperature alloy turbine working blades, thereby improving the grinding efficiency of the single-crystal blades.

[0005] The present invention is achieved through the following technical solutions:

[0006] A high-speed grinding method for a single-crystal high-temperature alloy turbine blade comprises the following steps:

[0007] S1: According to the minimum high-speed grinding wheel linear speed and the minimum diameter of the grinding wheel, the minimum rotation speed of the grinding wheel shaft of the processing equipment is obtained based on the linear speed formula;

[0008] S2: Based on the ratio of the linear speed of the roller and the grinding wheel and the minimum diameter of the roller shaft, the minimum linear speed of the roller is obtained, and the minimum rotation speed of the roller shaft of the processing equipment is obtained;

[0009] S3: Based on the minimum rotation speed of the grinding wheel shaft and the roller shaft, determine the suitable high-speed grinding equipment and grinding wheel; under the initial high-speed grinding wheel linear speed requirement, based on the single abrasive grain cutting thickness calculation formula, keep the processing depth unchanged, increase the feed speed, obtain the initial grinding wheel feed speed, and conduct multiple tests on the parts;

[0010] S4: Inspect the processed parts through surface quality inspection, adjust the grinding wheel linear speed and feed speed, adopt segmented processing method, obtain the final processing parameters, and complete the processing.

[0011] Furthermore, in step S1, the minimum linear speed of the high-speed grinding wheel is 35 m / s, and in step S4, the linear speed of the grinding wheel is adjusted to 40 m / s.

[0012] Furthermore, the linear velocity formula is:

[0013]

[0014] Where n is the rotation speed, R is the radius, and the minimum diameter of the grinding wheel that can be used is 200mm; 60 is the conversion of minutes to seconds, and 1000 is the conversion of meters to millimeters.

[0015] Furthermore, according to the linear speed formula, the minimum rotation speed of the grinding wheel shaft of the processing equipment is 3342 r / min, and the minimum rotation speed of the roller shaft of the processing equipment is 4679 r / min.

[0016] Furthermore, the linear speed ratio of the roller and the grinding wheel is 0.7-0.8.

[0017] Furthermore, the minimum linear velocity of the roller is 24.5 m / s, and the minimum diameter of the roller is 100 mm.

[0018] Furthermore, the segmented processing method is a processing method that uses two stages, a high-speed feed stage and a low-feed stage, under the adjusted grinding wheel linear speed;

[0019] The high-speed feeding stage is to use a high-speed feeding speed to process the first preset depth;

[0020] The low feed stage is a process of machining a second preset depth at a low feed speed.

[0021] Furthermore, the calculation formula for the thickness of a single abrasive grain is:

[0022]

[0023] Among them, a g is the cutting thickness of a single abrasive grain, λ is the effective abrasive grain spacing, Vs is the grinding wheel linear speed, Vw is the workpiece feed speed, a p is the grinding depth and d is the grinding wheel diameter.

[0024] Furthermore, during the grinding process, a flushing pressure of not less than 9 Bar is provided to the roller and the grinding wheel, and a cooling coolant of not less than 12 Bar is provided to the parts.

[0025] Furthermore, the surface quality inspection includes macroscopic and microscopic inspection of the processed surface, the macroscopic inspection includes fluorescent inspection of burns, ripples and cracks, and the microscopic inspection includes surface roughness inspection using optical instruments and surface integrity inspection using electron microscopy.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects:

[0027] The present invention provides a high-speed grinding method for a single-crystal high-temperature alloy turbine blade. According to the minimum high-speed grinding wheel linear speed and the minimum diameter of the grinding wheel, the minimum rotation speed of the grinding wheel shaft of the processing equipment is obtained based on the linear speed formula; based on the ratio of the roller to the linear speed of the grinding wheel and the minimum diameter of the roller shaft, the minimum value of the roller linear speed is obtained, and the minimum rotation speed of the roller shaft of the processing equipment is obtained; based on the minimum rotation speed of the grinding wheel shaft and the roller shaft, suitable high-speed grinding equipment and grinding wheels are determined; under the initial high-speed grinding wheel linear speed requirement, based on the single abrasive grain cutting thickness calculation formula, the processing depth is kept unchanged, and the progress is improved. Feed speed, get the initial grinding wheel feed speed, and conduct multiple tests on the parts; inspect the processed parts through surface quality inspection, adjust the grinding wheel linear speed and feed speed, adopt a segmented processing method, get the final processing parameters, and complete the processing; this application adopts a high-speed grinding process for single crystal blades, and through equipment selection, high-speed grinding wheel selection, processing parameter formulation and surface quality evaluation, the grinding efficiency and surface quality of single crystal material turbine working blades are improved. The grinding efficiency of this application is improved by more than three times, avoiding the occurrence of surface ablation of parts and improving the processing quality of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of high-speed grinding of a single-crystal high-temperature alloy turbine working blade of the present invention;

[0029] Figure 2 A schematic diagram of high-speed grinding of a single-crystal high-temperature alloy turbine working blade according to the present invention;

[0030] Figure 3 A microscopic schematic diagram of grinding a single crystal blade using the existing technology;

[0031] Figure 4 It is a microscopic schematic diagram of grinding a single crystal blade according to the present invention.

[0032] In the figure: 1. roller; 2. grinding wheel; 3. parts; 4. flushing nozzle; 5. cooling nozzle. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 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 should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] The present invention provides a high-speed grinding method for single-crystal high-temperature alloy turbine blades, such as Figure 1 and Figure 2 As shown, the following steps are included:

[0037] S1: According to the minimum high-speed grinding wheel linear speed and the minimum diameter of the grinding wheel, the minimum rotation speed of the grinding wheel shaft of the processing equipment is obtained based on the linear speed formula;

[0038] S2: Based on the ratio of the linear speed of the roller and the grinding wheel and the minimum diameter of the roller shaft, the minimum linear speed of the roller is obtained, and the minimum rotation speed of the roller shaft of the processing equipment is obtained;

[0039] S3: Based on the minimum rotation speed of the grinding wheel shaft and the roller shaft, determine the suitable high-speed grinding equipment and grinding wheel; under the initial high-speed grinding wheel linear speed requirement, based on the single abrasive grain cutting thickness calculation formula, keep the processing depth unchanged, increase the feed speed, obtain the initial grinding wheel feed speed, and conduct multiple tests on part 3;

[0040] S4: The processed part 3 is inspected through surface quality inspection, the grinding wheel linear speed and feed speed are adjusted, a segmented processing method is adopted, the final processing parameters are obtained, and the processing is completed.

[0041] Preferably, the minimum linear speed of the high-speed grinding wheel in step S1 is 35 m / s, and the linear speed of the grinding wheel is adjusted to 40 m / s in step S4.

[0042] Preferably, the linear velocity formula is:

[0043]

[0044] Where n is the rotation speed, R is the radius, and the minimum diameter of the grinding wheel 2 that can be used is 200 mm; 60 is the conversion of minutes to seconds, and 1000 is the conversion of meters to millimeters.

[0045] Furthermore, according to the linear speed formula, the minimum rotation speed of the axis of the grinding wheel 2 of the processing equipment is:

[0046]

[0047] Preferably, the linear speed ratio of the roller 1 and the grinding wheel 2 is 0.7-0.8.

[0048] Preferably, the minimum linear velocity of the roller 1 is 24.5 m / s, and the minimum diameter of the shaft of the roller 1 of the processing equipment is 100 mm.

[0049] Preferably, according to the linear speed formula, the minimum rotational speed of the shaft of the roller 1 of the processing equipment is 4679 r / min.

[0050] Preferably, the calculation formula for the cutting thickness of a single abrasive grain is:

[0051]

[0052] Among them, a g is the cutting thickness of a single abrasive grain, λ is the effective abrasive grain spacing, Vs is the linear speed of the grinding wheel, Vw is the workpiece feed speed, a p is the grinding depth, and d is the diameter of the grinding wheel 2.

[0053] Preferably, the segmented processing method is a processing method using two stages, a high-speed feed stage and a low-feed stage, under the adjusted grinding wheel linear speed;

[0054] The high-speed feeding stage is to use a high-speed feeding speed to process the first preset depth;

[0055] The low feed stage is a low-speed feed stage for processing the second preset depth; it should be noted that the high-speed feed stage will cause damage such as ablation to the surface of the part 3 due to the high speed, while the low feed stage will not cause damage such as ablation, and at the same time, the damage such as ablation in the previous stage will be eliminated, which can improve efficiency and production yield at the same time.

[0056] Preferably, during the grinding process of the part 3 , the flushing nozzle 4 is used to provide a flushing pressure of not less than 9 Bar to the roller 1 and the grinding wheel 2 , and the cooling nozzle 5 is used to provide a cooling coolant of not less than 12 Bar to the part 3 .

[0057] Preferably, the surface quality inspection includes macroscopic and microscopic inspections of the processed surface, the macroscopic inspection includes fluorescent inspections of burns, ripples and cracks, and the microscopic inspection includes surface roughness inspection using optical instruments and surface integrity inspection using electron microscopy.

[0058] Example:

[0059] Take the high-speed grinding of the tenon teeth of a certain type of DD6 single crystal material high-pressure turbine working blade as an example. Since the tenon teeth are not only the positioning surface for the subsequent processing of part 3, ensuring the size of the subsequent processing, but also the assembly and connection part of the turbine rotor, it is the most important part of the entire blade machining, and the processing requirements are the most stringent. The working surface profile is 0.016mm, the roughness is Ra0.8mm, the non-working surface profile is 0.02mm, and the roughness is Ra1.6. The processing content is:

[0060] Select a CNC grinder suitable for high-speed grinding for processing: The maximum speed of the grinding wheel 2 axis of a five-axis CNC grinder is 10000r / min, and the maximum speed of the roller 1 axis is 6000r / min. In the follow-up dressing mode, roller 1 rotates counterclockwise, and grinding wheel 2 rotates clockwise. The ratio of the linear speed of roller 1 to that of grinding wheel 2 is 0.8. The maximum diameter of roller 1 is 130mm. According to the linear speed formula Where n is the rotation speed and R is the radius. Through calculation, it is known that the maximum linear speed that the roller 1 of the five-axis CNC grinder can reach is:

[0061] According to the ratio of the linear speed of roller 1 and grinding wheel 2, that is, Vroll / Vsand=0.8, it can be concluded that the maximum linear speed of grinding wheel 2 is Vsand=Vroll / 0.8=40.82 / 0.8=51.028m / s. The maximum diameter of grinding wheel 2 is 300mm. Generally, grinding wheel 2 is replaced when it is worn to 200mm. The axis speed of grinding wheel 2 can be calculated as:

[0062]

[0063] The speed of the grinding machine meets the requirements of high-speed use. At the same time, the maximum coolant pressure of the equipment is 18bar, which can meet the pressure of the flushing nozzle 4 of not less than 9Bar and the pressure of the cooling nozzle 5 of not less than 12Bar. The flushing pump acts on the dressing process of the roller 1 and the grinding wheel 2, mainly removing the sand generated by the dressing of the grinding wheel 2. The cooling pump acts on the processing surface of the part 3 to reduce the processing temperature and prevent the part 3 from burning.

[0064] Selection of high-speed grinding wheel 2: The domestic new type of grinding wheel 2 abrasive is micro-fine corundum. Compared with ordinary white corundum and mixed corundum abrasives, micro-fine corundum abrasive has the advantages of high strength and good self-sharpening, which can keep the shape of grinding wheel 2 well and is suitable for the grinding of high-temperature alloy turbine blades. At the same time, the safe linear speed of the grinding wheel 2 sintered by this abrasive can reach 50m / s, which meets the requirements of high-speed grinding. The micro-fine corundum abrasive is selected for experimental processing.

[0065] Use efficient processing parameters for processing, increase the linear speed and feed speed of grinding wheel 2, and use segmented processing to improve the processing efficiency of part 3; according to the safety linear speed requirements of grinding equipment and high-speed grinding wheel 2, and according to the single abrasive cutting thickness formula, under the premise of keeping the processing depth unchanged and improving the processing efficiency, the linear speed of grinding wheel 2 is selected to be 40m / s, and the feed speed of part 3 is 600mm / min. After continuous processing attempts on site and monitoring of the equipment processing power, the feed speed can be increased to 1200mm / min while ensuring that the equipment processing power is not more than 15% of the total power; however, due to the poor grindability of DD6 single crystal material parts and sticking of the tool, when the linear speed of grinding wheel 2 is 40m / s and the feed speed is 1200mm / min, when the metallographic inspection of the surface of part 3 is performed, it is found that the surface is ablated, and the ablation depth is not more than 0.01mm, such as Figure 3 As shown; in order to ensure the surface processing quality of part 3, a segmented processing method is adopted, and the grinding wheel 2 is processed by reducing the feed speed, and the feed speed is reduced from 1200mm / min to 200mm / min. The surface of part 3 is subjected to metallographic inspection, and no ablation occurs on the microscopic surface, as shown Figure 4 The specific processing parameters determined are shown in Table 1:

[0066] Table 1

[0067]

[0068] Surface quality inspection: The surfaces of the two test pieces processed with the above high-speed parameters were inspected. Visually, there were no burns or ripples. The processed dimensions were qualified and the fluorescence inspection was qualified. After optical instrument inspection, the surface roughness reached Ra0.527μm. After metallographic inspection, the surface integrity met the requirements, as shown in Table 2.

[0069] Table 2

[0070]

[0071]

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for high-speed grinding of single-crystal high-temperature alloy turbine blades, characterized in that: The following steps are involved: S1: According to the minimum high-speed grinding wheel linear speed and the minimum diameter of the grinding wheel, the minimum rotation speed of the grinding wheel shaft of the processing equipment is obtained based on the linear speed formula; S2: Based on the ratio of the linear speed of the roller and the grinding wheel and the minimum diameter of the roller shaft, the minimum linear speed of the roller is obtained, and the minimum rotation speed of the roller shaft of the processing equipment is obtained; S3: Based on the minimum rotation speed of the grinding wheel shaft and the roller shaft, determine the suitable high-speed grinding equipment and grinding wheel; under the initial high-speed grinding wheel linear speed requirement, based on the single abrasive grain cutting thickness calculation formula, keep the processing depth unchanged, increase the feed speed, obtain the initial grinding wheel feed speed, and conduct multiple tests on the parts; S4: Inspect the processed parts through surface quality inspection, adjust the grinding wheel linear speed and feed speed, adopt segmented processing method, obtain the final processing parameters, and complete the processing; The minimum high-speed grinding wheel linear speed in step S1 is 35 m / s, and the grinding wheel linear speed is adjusted to 40 m / s in step S4; The linear velocity formula is: Where n is the rotation speed, R is the radius, and the minimum diameter of the grinding wheel that can be used is 200mm; 60 is the conversion of minutes to seconds, and 1000 is the conversion of meters to millimeters; According to the linear speed formula, the minimum speed of the grinding wheel shaft of the processing equipment is 3342r / min, and the minimum speed of the roller shaft of the processing equipment is 4679r / min; The linear speed ratio of the roller and the grinding wheel is 0.7-0.8; The minimum linear speed of the roller is 24.5 m / s, and the minimum diameter of the roller is 100 mm; The segmented processing method is a processing method that uses two stages, a high-feed stage and a low-feed stage, under the adjusted grinding wheel linear speed; The high-speed feeding stage is to use a high-speed feeding speed to process the first preset depth; The low feed stage is machining a second preset depth at a low feed speed; The calculation formula for the cutting thickness of a single abrasive grain is: Among them, a g is the cutting thickness of a single abrasive grain, λ is the effective abrasive grain spacing, Vs is the grinding wheel linear speed, Vw is the workpiece feed speed, a p is the grinding depth, d is the grinding wheel diameter; During the grinding process, the roller and grinding wheel are provided with a flushing pressure of not less than 9 Bar, and the parts are provided with cooling liquid of not less than 12 Bar; The surface quality inspection includes macroscopic and microscopic inspection of the processed surface. The macroscopic inspection includes fluorescent inspection of burns, ripples and cracks. The microscopic inspection includes surface roughness inspection using optical instruments and surface integrity inspection using electron microscopy.

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