An eddy-current method for crack growth or propagation measurement and experimental investigation of the characteristics of crack velocity
✍ Scribed by Chao-Tsien Tang; Ya-Peng Shen
- Publisher
- Elsevier Science
- Year
- 1982
- Tongue
- English
- Weight
- 94 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0013-7944
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✦ Synopsis
In this paper the general approximate method is used for calculating the stress intensity factor of the 9th grade disk of 31-25-2 type steam turbine with a radial crack in the corner of the key-slot and the fracture toughness of the material of the disk 34CrNi3Mo steel is determined. The K,< obtained from the large specimen is 496 kg/mm3" and that obtained from the .I,, of the small specimen is within 504 kg/mm3'* + 5%. Both the single-specimen method and the resistance curve method are used in Ji, determination.
According to K, of the disk with a crack at the key-slot and the K,, of the material of the disk, the critical length of the crack at the key-slot of the 9th grade disk of 31-25-2 type steam turbine is found to be equal to 63.5 mm while the critical length of the crack measured from the fracture section of a similar disk is 65-70mm. The good coincidence shows that the results of the calculation and the experiment are credible.