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White Spots on surface after Annealing and Pickling SS

(oxidising atmosphere) inside to ensure complete fuel combustion.

Biswabasu Roy Chowdhury

2006

After annealing & pickling of cold rolled finished SS white spots of various patterns are observed on surface which are even not removable by means of buffing by 200 grit silicate emery paper.The furnace is continuous LPG fired furnace with 5-12% excess oxygen

2006

The oxidising flames are required not only to ensure complete combustion but to ensure complete removal of oil on CR surface.Adjust at least two of the burners in top and bottom side in 1st section in such way to have long flame with sweeping action on the surface.It should solve the problem. Also check sulfur (Merkapten) content of the LPG.

S.K.Subramanian

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