SMAW Grade 9/10 oxyacetylene welding.pptx

SMAW Grade 9/10 oxyacetylene welding.pptx

1. Oxy acetylene welding

2. Gas welding performed by burning a combustible gas with air or oxygen: results in a concentrated flame of high temperature purpose of flame is to heat and melt the parent metal and filler rod.

3. Oxy acetylene welding

4. Gas flame correct adjustment of flame is important for reliable work. when oxygen and acetylene are supplied in nearly equal volumes a neutral flame is produced having a maximum temperature of 3200ºC condition of flame is determined by its appearance. neutral flame is desired for most welding operation. When excess of oxygen is used –oxidizing flame. When excess of acetylene is used –carburizing flame.

5. Neutral flame Neutral flame has two definite zones sharp brilliant cone extending a short distance from the tip of torch Outer envelope –bluish in colour . inner cone develops heat and the outer envelope protects the molten metal from oxidation neutral flame is used for welding steel, SS, C.I, Cu, AL, etc.

6. carburizing flame. Percentage of acetylene is more and 3 zones sharply defined inner cone intermediate cone of whitish colour (feather) bluish outer cone the length of intermediate cone is an indication of proportion of excess acetylene in flame. While welding steel ,the presence of more acetylene tend to give the weld a higher carbon content then parent metal ,resulting in a hard and brittle weld.

7. oxidizing flame percentage of oxygen is more have two zones small inner cone which has purple colour outer cone/envelope this flame is used for welding brass metal