As a part of an investigation of mild steel coated electrode, the effect of coating on the specific gravity of the deposited metal was studied. The single V weld of mild steel plates and the all deposited metals were made with A. C. under various conditions using some different kinds of coatings. The specific gravity of the deposited metal was measured and the X-ray test was carried out for comparison. When SiO2 is rich in the coating the specific gravity of deposit is poor, but it is not only

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... ue to the blow holes but also slag inclusions. Farthermore, the specific gravity of the deposited metal is not always decrease deven if the silicate degree of coating is increased. With a coated electrode of lower arc voltage a good specific gravity is gained when suitable welding current is applied. With higher are voltage and excessive welding current, a good specific gravity is not always gained. The gases generated from the coating do not always ecrease the specific gravity of deposited metal, however, it may be different according to the kinds of coatings and properties of gases. It is an algebraic sum of all the properties of coating material, melting point, fluidity etc., which affect to the specific gravity of deposited metal and the conclusion is rather difficult under various influences of many factors.