| 摘要 |
A weld temperature distribution indicator, for non-destructive testing of welded polyethylene pipes, comprises an alternating arrangement of color and/or melt transformation materials on an indicator support. A weld indicator, for displaying temperature distributions during the thermographic non-destructive testing of electrically welded sleeve connections of polyethylene pipes, comprises a combination of color and/or melt transformation materials applied in their color change and/or melting temperature order in an alternating grating or linear arrangement on an indicator support so as to provide, on heating the electric welding sleeve, colored isotherms or a stepped color arrangement contrasting with the color of the indicator support. The indicator support consists of foil, paper or fleece and its indicator coating is covered preferably with a sealed transparent protective layer. |
