Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Non Destructive Subsurface Crack Detection Technique

IP.com Disclosure Number: IPCOM000052391D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Nikolsky, G: AUTHOR

Abstract

This technique can be used to determine subsurface cracks in metal.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Non Destructive Subsurface Crack Detection Technique

This technique can be used to determine subsurface cracks in metal.

The metal part suspected of failure is first coated with a medium consistency silicone grease, such as MOLYKOTE* Type 33. Then a strip of colesteric liquid crystal is applied over the grease, so the colesteric liquid crystal is held to the metal part in the area of the suspected cracks. Heat is applied to one side of the failing area. Any cracks in the metallic body will create a discontinuity as well as a barrier to the thermal heat transfer. The presence of cracks will create a very narrow rainbow nit-line approximately 1/32 of an inch wide in the area between the application of the heat and the crack. If the metal part were not cracked, the variation in color of the colesteric material would be widely spaced and would move slowly away from the heat source. * Trademark of Dow Corning Corporation.

1