JP2019124183A - Process of manufacture of firtree type turbine blade - Google Patents

Abstract

To provide a process of manufacture of firtree type turbine blade.SOLUTION: This invention relates to a process of manufacture for manufacturing in a precision form a firtree type turbine blade made of hammered raw material, said process of manufacture comprises a step for cutting an original raw material constituting the blade to fit a set standard and surface cutting a reference plane, a step of cutting a foot part in set dimension and shape, a step for punching an upper end of the original raw material through a drilling work, fixing the upper end of the original raw material to a machine tool and fixing the cut foot part to a jig; a step for cutting an air foil in set size and shape; a step for cutting a dummy of an upper end left when the air foil cutting is performed; and a step for executing a shot peening for hardening the foot part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of manufacturing a turbine blade, and more particularly to a technique for manufacturing a firm and precise turbine blade of a fir tree type through a forging process.

  In a turbo charger used for a marine engine, a turbine blade adheres to a turbine wheel and rotates.

  The structure of the turbine blade, as is well known, is composed of a foot portion and an airfoil, the foot portion is mounted on the turbine wheel, and the airfoil is by a wing structure twisted at an angle Become.

  Conventionally, turbine blades have been manufactured through a casting process, but the manufacturing process is complicated and there is a problem that the manufacturing period takes a long time, and in particular, materials that are difficult to handle as a casting process are applied It is made to manufacture using a forging material by this.

  As such, in the manufacturing process, although the manufacturing cost and the period have to be taken into consideration, the firm and precise processing should be prioritized prior to that, but the turbine blade using a forged material In the case of manufacturing, there is a need for a manufacturing method that can satisfy such requirements.

  The problem to be solved by the present invention is to provide a method of manufacturing a turbine blade that can manufacture a turbine blade firmly and precisely using a forging material.

  In order to solve the above problems, the present invention is a method of manufacturing a turbine blade in which a foot portion and an airfoil are integrally formed, and a raw material constituting the blade is made to meet a preset standard. The steps of cutting and chamfering the reference surface, cutting the foot portion to a preset size and shape, and drilling the upper end of the raw material by a drilling operation, the machine tool of the raw material The upper end is fixed and the cut foot portion is fixed to a jig, the airfoil is cut to a preset size and shape, and the upper end dummy which remains when the airfoil is cut (dummy) And C.), and performing shot peening for curing the foot portion. It is.

  The method may further include performing a balancing test to measure a positional deviation of weight when the blade rotates after the shot peening.

  Desirably, cutting of the foot portion and the airfoil is performed by performing rough cutting and rough cutting in order.

  According to the above configuration, the foot portion is processed in the raw material state, and the foot portion is fixed to a jig that can take sufficient remaining force, and then it is stable by advancing the airfoil cutting operation, and further efficiency It is possible to manufacture a turbine blade.

It is drawing which shows the turbine blade manufactured by the manufacturing method of this invention. It is drawing which shows the turbine blade manufactured by the manufacturing method of this invention. It is a flowchart explaining the manufacturing method of the turbine blade by the present invention. It is drawing which shows the state which cutting of the foot part completed. It is a figure which shows the state which fixed the upper end and lower end of the raw material prior to the cutting of an airfoil. It is drawing which shows the state which the process completed by 5-axis machine tool. 5 is a drawing showing a turbine blade from which a dummy has been removed.

  It should be noted that the technical terms utilized in the present invention are merely used to describe specific embodiments and are not intended to limit the present invention. In addition, technical terms used in the present invention are interpreted as meaning generally understood by a person of ordinary skill in the art to which the present invention belongs unless it is defined in the present invention to a particularly different meaning. It is not intended to be interpreted as inclusive or to be unduly reduced. In addition, when technical terms used in the present invention are not technical technical terms that can not accurately express the spirit of the present invention, technical terms that can be correctly understood by those skilled in the art. It has to be replaced and understood. Also, the general terms used in the present invention should be interpreted as previously defined or in context, and should not be interpreted as having an overly-reduced meaning.

  Hereinafter, the present invention will be described in detail with reference to the attached drawings.

  1A and 1B show a turbine blade manufactured by the manufacturing method of the present invention.

  The blade 100 is integrally formed with the foot portion 110 and the airfoil 120, but the foot portion 110 has a corrugated surface so as to be coupled to and firmly attached to the turbine wheel. Also, the airfoil 120 has an end tip twisted at an angle to the foot portion 110 connected to the platform.

  FIG. 2 is a flow chart illustrating a method of manufacturing a turbine blade according to the present invention.

  The raw material 10 is cut so as to meet the preset standard, and the reference surface is chamfered (step S21).

  The cut original material 10 has six surfaces, ie, the right and left sides, front and back, and upper and lower surfaces, which are uneven because the surface is uneven, and processed precisely, for example, about 5 mm thicker than the blade standard. The raw material 10 can be cut by triaxial milling.

  After the raw material 10 is cut in accordance with the preset standard, the foot portion 110 and the airfoil 120 are processed into accurate dimensions.

  According to the present invention, after performing the cutting process on the foot portion 110, the cutting process on the airfoil 120 is performed.

  Explaining the reason related to it, if the structure of the turbine blade 100 generates a lot of remaining power when processing the airfoil 120, it is necessary to take a reference point for processing the airfoil 120. is there.

  In other words, when processing the airfoil 120 without taking the reference point, the blade 100 becomes unstable and it is difficult to perform precise processing due to the remaining power generated when the airfoil 120 is processed.

  Therefore, in the raw material 10, after precision processing of the foot portion 110 with a creep feed grinder, a jig 30 capable of taking sufficient remaining force is manufactured, and the jig 30 with respect to the reference point of the foot portion 110 is manufactured. You have to use 30 and hold the raw material 10 with firm power.

  In conclusion, it is more stable and more efficient to process the foot portion 110 first than to process the airfoil 120.

  As shown in FIG. 3, the roughing (rough machining) of the foot portion 110 is performed (step S22).

  For example, it can process by wire EDM cutting (wire EDM cutting), and machining allowances work about +0.8 mm in one side in order to cut once more at the time of precision cutting.

  After machining, if the dimensional inspection result is out of tolerance, a defect may occur during creep feed grinding, so dimensional inspection is performed on the entire portion specified in the dimensional inspection record, and the data is processed after analysis.

  Next, since there is a buildup of about 1 to 2 mm from the finish value dimension by roughing, precise processing is performed on it by creep feed grinding to satisfy the line contour degree tolerance and the surface roughness tolerance (step S23).

  Here, the profile of the foot portion 110 should be enlarged by a factor of 20 so that the tolerance region does not deviate from the upper limit value and the lower limit value.

  When the cutting operation of the foot portion 110 is completed, the airfoil 120 is cut, but before cutting the airfoil 120, the installation operation of the raw material 10 in which the foot portion 110 for precision operation is processed is preceded (Step S24).

  That is, after the foot portion 110 is cut and processed, the airfoil 120 of the turbine blade 100 is cut. For that purpose, it is necessary to fix the upper end and the lower end of the turbine blade 100, and the lower end is processed The foot portion 110 is fixed to the jig 30.

  Referring to FIG. 4, the upper end of the raw material 10 is drilled (12) by a drilling operation to accurately fix the raw material 10 on a 4-axis machine tool (not shown).

  Next, the raw material 10 corresponding to the airfoil 120 is roughly cut with a processing allowance (step S25).

  The machining allowance can be set differently depending on the part. For example, a machining allowance of about 1.5 mm is given for the platform or tip, and a machining allowance of about 0.5 mm for the shank. You can put

  At this time, as described above, the jig 30 is fixed so as not to damage the profile of the foot portion 110 for which the precision cutting operation has been completed.

  When roughing of the airfoil 120 is completed, precision cutting is performed (step S26).

  Precision machining must increase dimensional accuracy and ensure that all standards fall within tolerances, and cuts with a 5-axis machine tool (not shown) for precision machining.

  FIG. 5 shows a state in which machining is completed in the 5-axis machine tool.

  As shown in FIG. 5, after completing the 5-axis precision cutting of the airfoil 120, the upper end dummy 11 left for fixing is cut using a band saw. And finish the part with a grinder (step S27).

  FIG. 6 shows the turbine blade with the dummy 11 removed.

  After the dummy 11 is removed, a shot peening operation is additionally performed to cure the foot portion 110 (step S28).

  That is, since the foot portion 110 of the blade 100 is assembled in alignment with the rotor shaft, a lot of hardness and resistance are required, and thus the shot peening operation is performed. As well known, it refers to a cold working method in which a large number of small steel particles called shot are sprayed at a speed of 20 to 50 cm / sec onto the surface of a workpiece, and the surface on which shot peening has been performed is surface hardened Causes compressive residual stress up to about 0.3 mm of the surface layer.

  After completion of the shot peening operation, to measure compressive residual stress, measure residual stress 100 μm deep from the surface and use X-ray stress analysis method.

  A total of three points are measured, and at all points, the residual stress (MPa) value falls within the preset target range of 400 to 600 MPa.

  Finally, a balancing test is performed to measure the positional deviation of weight when the turbine blade 100 is assembled, assembled and rotated on the rotor shaft (step S29).

  In a rotating body such as a turbine blade, if there is an imbalance, a large centrifugal force is generated on one side, vibration and noise are generated, the shaft is bent, leading to failure.

  The balancing test is carried out at a rotational speed of 400 rpm or more per minute, and the result value must be 580 gmm or less in the wheel part.

  Although the embodiments of the present invention have been mainly described above, it goes without saying that various modifications can be made at the level of those skilled in the art. Accordingly, the scope of the present invention should not be interpreted as being limited to the embodiments described above, but rather by the scope of the claims.

  The method of manufacturing a fartree-type turbine blade of the present invention is effectively applicable to, for example, the technical field related to shipbuilding.

10 Raw Material 11 Dummy 30 Jig 100 Turbine Blade 110 Foot Part 120 Airfoil

Claims (3)

A method of manufacturing a Fartree-type turbine blade, comprising:
Cutting an original material constituting the blade so as to meet a preset standard, and chamfering a reference surface;
Cutting the foot portion to a preset size and shape;
Drilling the upper end of the raw material by a drilling operation, fixing the upper end of the raw material to a machine tool, and fixing the cut foot portion to a jig;
Cutting the airfoil to pre-set dimensions and shapes;
Cutting a top dummy remaining at the time of cutting the airfoil;
Shot peening the foot portion;
Measuring residual stress of a certain depth from the surface of the foot portion, and checking whether residual stress (MPa) values at all points of the foot portion fall within a preset target range A method of manufacturing a turbine blade comprising:   The method for manufacturing a turbine blade according to claim 1, further comprising performing a balancing test to measure a weight position deviation during rotation of the blade after the shot peening.   The method for manufacturing a turbine blade according to claim 1, wherein the preset target range of the residual stress value is 400 to 600 MPa at a depth of 100 μm from the surface.