Passive Layer Test Pen
A test pin for quickly checking the passive layer on steels after welding. It reacts to free iron ions and shows whether the passive layer is intact.
Physicochemical Mechanism of Action
The test pen contains a chemical reagent that reacts with free iron ions. If the passive layer is intact, there are no free iron ions and the pen remains unchanged. If the passive layer is damaged or missing, the reagent reacts and the pen changes color.
Metallurgical Relevance & Welding Risks
A damaged passive layer can lead to corrosion and reduce the part's service life. The test pen allows for quick checks to ensure the passive layer has been restored.
Workshop Practice & Instructions
Use the test pen after weld post-cleaning. Press the pen on the steel surface and observe the color change. Unchanged pen means an intact passive layer; a color change indicates a damaged or missing layer.