JPS63112039A - Forging method for turbine blade stock - Google Patents

Abstract

PURPOSE:To prevent the generation of under fill and a burr of an overprotrusion of thickness in each cross section of a profile of a turbine blade, by forming an eccentric bending material in an outlet side by applying a bending for allowing the axis center to run along an edge line for connecting a divide, at the stage of bringing a perform to bending. CONSTITUTION:The center position in case when it has been allowed to be eccentric so as to obtain a condition that the center of a profile corresponding part 2a of a perform is not placed on the center line of the upper and the lower profile forming dies 11, 12, and under fill is not generated in both an outlet side 8 and an inlet side 7 is called a divide 16 of a plastic flow. This divide position can be determined definitely by using a plastic material such as clay, etc. by an experiment. The perform 10 is brought to bending forming so as to run along an edge line 17 for connecting a divide in each cross section a profile forming material 13c with a line, a bending material 18 being eccentric in the outlet side 8 is obtained. Subsequently, the bending material 18 is formed to a forging material before a machine work, in a forming stage of the post stage consisting of torsion forming and finish forming.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improved forging method for manufacturing a turbine blade material having a complex shape by stage forging including free forging and die forging.

(Prior art) Fig. 1 is a perspective view of an example of a turbine blade as a target product;
M2 diagram shows 1,000 diagrams.

Turbine blades are the most important functional components of a steam turbine, and their manufacturing cost accounts for approximately 60% of the entire turbine blade, and their quality greatly affects the performance, reliability, and durability of the turbine. The importance of the F1 node is the same in gas turbines, turbo compressors, etc.

As shown in Figures 1 and 2, the turbine blade (1)
is an integrated profile part (2), plan) 7 ohm (3)
and Atsube (4). Profile section (
2) from the profile root (5) to the profile tip (6)
Turn the screws all the way in. (This is the maximum twist angle between the base and tip of the noke.

The cross-sectional shape perpendicular to the axis of the profile part (2) is made according to the shape of a hydrodynamic airfoil, and has an asymmetrical shape with a complex curve from the fluid inlet side (7) to the outlet side (8), and the profile from the root to the tip. Both the wall thickness and shape have changed significantly.

Such a turbine blade (1) must be sequentially forged in several stages. FIG. 6 shows an example of the conventional molding process order and the shape of the molded product at that stage. The starting material (9) is preformed material, profile molded CBI
The product is made into a turbine blade (1) through twist forming (0, machining (G)).For those that pursue higher dimensional accuracy, twist forming (after finishing forming (G) after 0) is performed.
In addition, products with good forgeability may be subjected to finishing forming (g) directly after preforming (2) without profile forming or twist forming, and then subjected to machining. In the figure, (2a) shows the part of the preformed product which becomes the profile part (2).

It is a stepped round bar that is axially symmetrical about the origin (0) of the Y axis, or a stepped square bar that has a rectangular cross section that is mirror symmetrical to the Y axis. When this preformed material αQ is formed into a profile molding opening) or a final molding (g), the profile part (2) has a complex asymmetrical shape, so as shown in FIG. The part (2b
) is an unfitness without meat and a va with too much meat! 19
This is because the plastic flow resistance toward the fluid outlet side is large due to the difference in wall thickness of the profile, resulting in an unsuitable flow on this side.

(Means, functions and embodiments for solving the problems) The present invention has been made in order to solve the above-mentioned problems of the prior art. Preformed material
The axis position of the profile corresponding part (2a) of O is the Y axis, Y
Eccentrically move the shaft toward its origin (0) and toward the lower end (8).

Therefore, after preforming, the preform material α1 is bent using a bending die to bend the shaft core.

That is, in the method for forging a turbine blade material of the present invention, the starting material is forged into a preformed material in the preforming step, and then the preformed material is bent and formed so that its axis is aligned with the turbine blade. In order to prevent unsightliness and excessive protrusion in each cross-section of the profile, the bent material is bent along the ridgeline connecting the watersheds to create a bent material eccentric to the outlet side, and then the bent material is profile-formed, twisted, and finished. It is characterized in that it is made into a forged material before being machined in the forming stage of the post-process consisting of forming.

Hereinafter, the present invention will be specifically explained with reference to FIGS. 5, 6, and 7.

Figure 5 (a) shows a case where the center of the profile corresponding part (2a) of the preformed material α0 is placed on the center line of the upper and lower profile molding molds αη@, and the profiled material (15A) has no part on the outlet side (8). Mukai is born. Figure 5 (b) shows the preliminary shape α
When the corresponding part (2a) of the profile of O is placed largely off to the exit side (8), the unfitness (141 occurs on the inlet side (7)). Entrance side (
7) In the case where the preformed material αO is placed at the intermediate position as mentioned above so that both of them should occur, the position of the center of the profile corresponding part (2a) of the preformed material at this time is hereinafter referred to as the watershed QG of plastic flow. It is called.

The watershed position can be determined through experiments using plastic materials such as clay. It can also be determined by plastic mechanics analysis such as FEM.

FIG. 6(c) shows a profile molded material obtained by the method of the present invention, and when the watershed α arcs in each cross section of this profile molded material (150) are connected with a line, this line deviates from the center line of the blade. Hereinafter, this line will be referred to as the ridge line ση of plastic flow.
It is called. In the present invention, i- is the preformed material αQ of FIG. 6(A).
The corresponding part (2a) of the profile is bent and formed along the ridgeline 0η to obtain a bending-formed material (7) whose ridgeline α force shown in FIG. 6(b) matches that of FIG. 6(/1).

FIG. 7 shows an example of a process sequence for forming a turbine blade material according to the present invention. Steps equivalent to the prior art process of FIG. 3 are designated by the same reference numerals.

In the present invention, after the preforming (3), the above-mentioned axial bending C
Add the step F) and then proceed to profile forming (8). The subsequent steps are the same as before.

There are various methods of plastic mechanics analysis, one example of which is shown below.

That is, a method is adopted in which the blade is appropriately divided in the longitudinal direction, each cross section is divided into rectangular modules, and the slab method is applied to each module and added. Stress, forming force calculation formula,
The stress distribution, forming force, and thrust are determined from the stress calculation formula, and the product blade shape is changed by the reverse step method, and the midplane position is moved in stages to minimize damage to equipment and molds caused by unbalanced forces. Along with this, the shape of the wasteland is determined.

This calculation requires a short computer calculation time, and at the same time the watershed ridgeline is also known. (Effects of the Invention) According to the method of the present invention, turbine blade materials with complex shapes can be relatively easily sized under optimal forging conditions. Can be forged and formed with high precision.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an example of a turbine blade as a target product;
Figure 2 is a plan view of the same, and Figure 6 is the conventional molding process sequence.
Figure 4 is a cross-sectional view showing a defective profile forming state of the prior art; Figure 5 (A) is a cross-sectional view of a profile forming state where misdirection occurs on the exit side; FIG. 5(b) is a sectional view of the profile forming state in which misalignment occurs on the inlet side, FIG. 5(b) is a sectional view of the profile forming state of the present invention in which no misalignment occurs, and FIG. is a side view of a preformed material, FIG. 6(B) is a side view of a bending material in the process of the present invention, FIG. 6(C) is a side view of a profiled material according to the present invention, and FIG. 7 is a side view of the method of the present invention. FIG. 2 is a block diagram showing an example of the order of molding steps according to FIG. (1) - Turbine 1 node, (2) - Profile part, (2a) (2b') - Profile corresponding part, (3) - Platform, (4) Φ root, (5
)・ΦProfile root, (6)・Profile tip, (
7)...Inlet side, (8)ψ/Outlet side, (9)...Starting material, QO...Preformed material J (B)...Upper mold, @...Lower mold, Q3 (15A) (13B )(130)...Profile molding material, α徨...unsuitable, αυ...baIJ, IN...
watershed, a... ridgeline, (to)... bending material, (5)
... Preforming, (Bl... Profile forming, (0... Twisting forming, (to)... Machining, ■)... Finish forming, (1
? 5... Bending forming, (3) (■... Coordinates, (0)... Origin, (... Maximum torsion angle 0 drawing engraving (no change in content) Product 5 drawing (in (wa) 1, 2a (c) Written amendment to the procedures for calculation 6 and illustrations 7 (on February 2, 1985, 1, case description 1988 patent application No. 25734)
No. 9 No. 2, Title of the invention: Method for forging turbine blade material 3, Relationship with the case of the person making the amendment Patent Representative: Fuyuhiko Maki 4, Agent 650 6, Drawing subject to amendment (Fig. 5) ) 7. Correction details The above will be corrected as shown in the attached sheet.

Claims (1)

[Claims] The starting material is formed into a preformed material by forging in the preforming stage, and then the preformed material is bent and formed so that its axial center is at a watershed position in each cross section of the turbine blade profile where no underfilling or overhanging occurs. The bent material is bent along the ridgeline connecting the watersheds to create a bent material eccentric to the exit side, and then the bent material is forged before machining in the post-process forming stage consisting of profile forming, twisting forming, and finishing forming. A method for forging a turbine blade material, characterized in that it is made into a molded material.