Metallurgical Aspects Of SpatFree 113 :
* The steel contains 0.01% to 0.02% Oxygen. The oxygen content in the weld metal is as much as 0.02% to 0.03%. Excess oxygen has an adverse effect on the mechanical properties of the weld metal (specially impact strength) apart from formation of additional Ferrous Oxide.
* Oxygen content in the weld metal varies with arc length, welding current and the type of shielding employed.The coating of the electrode promotes a shield of slag that is not adequate, even with standard quality of electrode, to have lower level of oxygen in the metal.
* The contact of air with the weld pool may also increase the nitrogen content in the weld metal and that is very harmful. In open arc welding, the weld metal may contain as much as 0.12% to 0.18% of Nitrogen, while the parent metal contains 0.001% to 0.008% of Nitrogen only. The gaseous inclusions bring down the impact strength of the weld metal which in turn causes weld failure.
* The coating of SpatFree 113 helps to remove this problem, in the weld pool. This coating acts as a flux when the arc is formed, developing a film over the weld metal. This film protects this weld pool from the surrounding air, which is by and large very active, thus minimizing the reaction of Nitrogen and oxygen with the surrounding area. This action helps to get a clean and dense weld with improved mechanical and metallurgical properties.
Refinement of Metal :
Apart from protecting the weld pool form the ambient atmosphere, the coating, acting as a flux also partly removes oxygen from the molten metal by de-oxidation. The oxides being lighter than metal formed by de-oxidation of the weld pool floats up and is removed along with the molten slag, SpatFree 113 helps to refine the weld metal and improves the mechanical properties. Slag does not stick to the surface and is easily removed. Deep penetration of weld metal is yet another achievement.