The operations necessary to produce a desired or specified surface condition. Cleanliness is extremely important in welding applications. Foreign material, oxide, oil or grease must be carefully removed from the surface prior to welding.
Nickel (also cobalt) alloys are embrittled by sulfur, phosphorus, and metals with low melting points such as lead, zinc, and tin. Lead hammers, solders and wheels or belts loaded with these materials are frequent sources of contamination. Detrimental elements are often present in oils, paint, marking crayons, cutting fluids, and shop dirt. When welding nickel (also cobalt) alloys, It is particularly important that adequate attention be given to cleaning before applying heat from any source. Unless proven safe, all foreign mate- rial must be considered harmful in the presence of heat.
