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Process for applying internal compressive stresses in a shaft, in particular in shaft chamferings

A technology of internal stress and grooves, applied in the field of shaft grooves, can solve the problems of reduced service life and reduced durability, and achieve the effect of preventing the reduction of durability

Inactive Publication Date: 2009-06-17
SIEMENS AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the influence of this aggressive medium, the durability of the substrate is significantly reduced
However, a reduction in the durability of the base material such as a shaft in a low-pressure section turbine also disadvantageously reduces the service life of said shaft

Method used

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  • Process for applying internal compressive stresses in a shaft, in particular in shaft chamferings

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Embodiment Construction

[0018] figure 1 A section of a shaft 1 is shown, which is designed as a stepped shaft with successive steps 2 with different diameters D1 to D4 with respect to the central axis X, of which four are shown as an example rung 2. The illustrated exemplary shaft 1 is part of a low-pressure part turbine of a fluid machine, such as a steam turbine. The shaft 1 is produced, for example, from a material having cold ductile properties, such as 2-3.5-NiCrMoV steel for the production of ND shafts. However, the shaft can of course also be produced from other materials or combinations of materials.

[0019] A diameter transition region 3 or groove region is arranged in each case between two adjacent steps 2 . The diameter transition region 3 is slightly arched or convex with respect to the center axis X in the direction of the center axis X with a radius R.

[0020] In order to properly adjust the pressure internal stress of -100 to -400 MPa on the shaft surface, especially in the diame...

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Abstract

The invention relates to a method of introducing compressive residual stresses into shaft notches of a shaft which is configured as a stepped shaft having successive stages having a different diameter. Diameter transitions or notch regions are located between each two adjacent stages. The diameter transitions or notch regions are quenched in a controlled manner as part of a heat treatment of the shaft.

Description

technical field [0001] The invention relates to a method for introducing a pressure internal stress into a shaft groove of a shaft, which is configured as a stepped shaft with successive steps having different diameters, wherein each adjacent Diameter transition regions or groove regions are arranged between the steps of the . Background technique [0002] Such shafts are known and are used, for example, in fluid machines with a low-pressure part (ND), such as steam turbines, so these shafts can also be referred to as ND shafts. The shaft supports rotor blades which, together with associated guide vanes, form a cascade through which a flow medium, such as steam, flows. [0003] Especially in the low-pressure part of fluid machines there are shafts made of base materials with cold ductile properties, for example 2-3.5-NiCrMoV steel is used for the production of ND shafts. [0004] The flow medium fraction acts as a corrosive medium on components of the turbomachine, for exa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/28B23P25/00
CPCC21D9/28
Inventor M·布兰德尔T·-U·克恩C·里克特
Owner SIEMENS AG