SPECIAL FEATURES OF THE METALLURGY OF LASER WELDING.

The article presents results of investigations into the transfer of carbon, silicon, manganese, and titanium from the parent metal and also of nitrogen and oxygen from the gas phase into the metal of pearlitic and austenitic laser-welded joints and compares them with those obtained with other types of fusion welding. It is shown that the coefficients of pick-up of alloying elements during laser welding of steels in shielding gases are usually lower than for arc welding. The extent of transfer of nitrogen from the gas phase into the weld metal in laser welding of steels is one half to one third that in arc welding in shielding gases. Nitrogen can be used in many cases as the shielding gas in laser welding of steels.