Apr 29, 2013 · The combination of a substance or element like wood, iron, gasoline, etc, with oxygen. The process is fundamentally the same whether wood is consumed with fire or iron is turned into rust (iron oxide). In welding the oxygen of the air forms an oxide with the molten metal, thus injuring the quality and strength of the weld. Oxter plate
Dressing is the process used to clear the cutting surface of the grinding wheel of any dull grits and embedded swarf in order to improve the cutting action. Truing is the process employed to bring the wheel to the required geometric shop and also to restore the cutting action of a worn wheel. Question 190.