This standard specifies the dimensioning, tolerances and technical requirements of dovetail blade roots and blade root grooves for gas turbine compressor blades. This standard applies to dovetail blade roots and dovetail blade root grooves for gas turbine compressor blades. JB/T 6689-1993 Tolerances and technical requirements for dovetail root grooves for gas turbine compressor blades JB/T6689-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Gas Turbine Compressor
Blade dovetail root, groove, tolerance and technical requirements 1 Subject content and scope of application
JB/T6689—1993
This standard specifies the dimensioning, tolerance and technical requirements of the steam tail blade root and blade root groove of gas turbine compressor blades. This standard applies to dovetail blade root and steam tail blade root groove of gas turbine compressor blades. 2 Reference standards
GB2900.47 Electrical terminology
Gas turbine
3 Terms and symbols
3.1 Terms
3.1.1 Blade root groove
A groove with a certain size and shape that fixes the blade on the wheel (or rotor body) or cylinder (or holding ring). 3.1.2 Steam tail blade root (blade root groove)
The geometric figure of the cross section is approximately a trapezoidal blade root (blade root groove). 3.1.3 Side surface
The plane formed by the two waists of the blade root (blade root groove) cross section trapezoid, and the side surface is the load-bearing surface. 3.1.4 Top surface
The surface formed by the upper base of the blade root (blade root groove) cross section trapezoid. The top surface may be an imaginary curved surface or plane. 3.1.5 Bottom surface
The plane formed by the lower base of the blade root (blade root groove) cross section trapezoid. 3.1.6 Top angle
The angle between the two side surfaces.
3.1.7 Bottom angle
The angle between the bottom surface and the side surface.
3.1.8 Blade root (blade root groove) symmetry plane
The angle bisector of the top angle of the blade root (blade root groove). 3.1.9 Blade root (blade root groove) width plane
The plane used to determine the blade root (blade root groove) width is given in the design. The plane is parallel to the bottom surface and perpendicular to the blade root (blade root groove) symmetry plane. 3.1.10 Bottom surface height
The distance between the bottom surface and the blade root (blade root groove) width plane. 3.1.11 Top surface height
The distance from the intersection of the top surface and the blade root (blade root groove) symmetry plane to the blade root (blade root groove) width plane on the plane perpendicular to the blade root (blade root groove) symmetry plane and the width plane. 3.1.12 Blade root height
The distance from the intersection of the top surface and the blade root (blade root groove) symmetry plane to the bottom surface on the plane perpendicular to the blade root (blade root groove) symmetry plane and the width plane.
Approved by the Ministry of Machinery Industry on June 1, 1993
Implemented on January 1, 1994
3.1.13 Blade root (blade root groove) width
JB/T6689-1993
The distance between the two side surfaces on the blade root (blade root groove width plane. 3.1.14 Bottom surface width
The length of the lower base of the trapezoidal cross section of the blade root (blade root transverse). 3.1.15 Chamfer at bottom corner
The angle between the chamfer plane and the bottom surface.
3.1.16 Chamfer height at bottom corner
The height of the chamfer in the direction perpendicular to the bottom surface.
3.1.17 Transition arc at bottom corner
The transition arc between the bottom surface and the side surface of the blade root groove.||t t||3.1.18 Blade root (blade root groove) neck width
The width of the transition plane between the top surface and the two side surfaces. 3.2 Symbols
The symbols shall be as specified in Table 1.
Blade root (blade root groove) symmetry plane
Blade root (blade root groove) width plane
Bottom surface height
Blade root height
Blade root (blade root groove) width
Bottom surface width
Chamfer at bottom corner
Height of bottom corner
Transition circle arc at bottom corner
Blade root (blade root groove) neck width
3.3 Some terminology diagrams are shown in Figures 1 to 4.
Blade root
Intake edge
Front butterfly
Fried wax surface| |tt||JB/T6689—1993
Figure 1 Blade
Figure 2 Wheel
Figure 3 Dovetail blade root
Rear increase surface
Ipecac
Rear spiral surface
Blade root symmetry surface
Blade root width plane
Benchmark selection
JB/T6689—1993
Figure 4 Dovetail blade root groove
Ipecac symmetry surface
Blade root width plane
The bottom surface of the blade root (blade root groove) is used as the first datum, and the symmetry surface of the blade root (blade root groove) is used as the second datum (Figure 5, Figure 6). Figure 5 Blade root
Figure 6 Blade root groove
5 Dimension, geometric tolerance standard Note and technical requirements JB/T6689-1993
5.1 Dimensions and geometric tolerances
5.1.1 The dimensions and geometric tolerances of the blade root with chamfered sides and bottom surfaces shall be as specified in Figure 7. 5.1.2 The dimensions and geometric tolerances of the blade root groove with arc-shaped smooth transitions between the side and bottom surfaces shall be as specified in Figure 8. Nd
5.1.3 The tolerance values ​​of the blade root width and blade root groove width shall be noted, and the height dimension of the bottom surface of the blade root (blade root groove) is the theoretical calculated dimension. 5.1.4 It is allowed not to mark the flatness requirements of the side. 5.1.5 The parallelism of the two generatrixes intersecting the two side surfaces of the blade root (blade root groove) and the width plane of the blade root (blade root groove), the blade root is represented by F, and the blade root groove is represented by Fc.
JB/T 6689-1993
5.1.6 Symmetry of the neck width to the second reference plane; the blade root is represented by Q, and the blade root groove is represented by Qc. 5.2 Technical requirements
5.2.1 When the gap between the blade root groove width and the blade root width is 0-0.2mm, it is necessary to check the top angle and the bottom angle on both sides; when the gap between the blade root groove width and the blade root width is greater than 0.2mm, it is only necessary to check the top angle and the bottom angle on one side. 5.2.2 The transition parts of the blade root (blade root groove) on each surface shall not have sharp corners and must be transitioned with an arc. 6 Dimension tolerance
6.1 The limit deviation of the size shall be as specified in Table 2
Blade root (blade root groove) width
Neck width
Limit deviation
±10°
Limit deviation
However, the bottom angle tolerance can be determined by the designer according to the assembly structure of the blade root and the blade root. Note: 1) The tolerance of the top angle should be guaranteed.
6.2 The root tolerance is divided into Class 1 and Class 2; Class 1 is used for the gap between the root groove width and the root width is greater than or equal to 0.2mm, and Class 2 is used for the gap between the root groove width and the root width is greater than 0.2mm. Parallelism and symmetry
Parallelism and symmetry shall be as specified in Table 3.
Parallelism
Symmetry
Blade cross
Surface roughness
The surface roughness of the root and the root groove is all 3. The surface roughness shall be specified on the design drawing. 66
JB/T 66891993
Appendix A
Marking example
(reference)
A1 The marking example of the root with the bottom surface of the root and the symmetry plane as the reference is shown in Figure A1. R0.5 All schools
Note; 1) Theoretical calculation size
A2 See Figure A2 for an example of blade root groove marking based on the bottom surface and symmetry plane of the blade root groove.87.9±0.03
Note: 1) Theoretical calculation size
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This standard was proposed by Nanjing Gas Turbine Research Institute. This standard is under the jurisdiction of Nanjing Gas Turbine Research Institute. This standard was drafted by Nanjing Steam Turbine Electric Machine Factory. The main drafters of this standard are Gu Biling and Zhuang Hongshan. A2
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