Spot welding of two steel sheets each $$2$$ $$mm$$ thick carried out successfully by passing $$4$$ $$kA$$ of current for $$0.2$$ seconds through the electrodes. The resulting weld nugget formed between the sheets is $$5$$ $$mm$$ in diameter. Assuming cylindrical shape for the nugget, the thickness of the nugget is ______________$$mm.$$

During a $$TIG$$ welding process, the arc current and arc voltage were $$50$$ $$A$$ and $$60$$ $$V,$$ respectively, when the welding speed was $$150$$ $$mm/min.$$ In another process, the $$TIG$$ welding is carried out at a welding speed of $$120mm/min$$ at the same arc welding voltage and heat input to the material so that weld quality remains the same. The welding current (in $$A$$) for this process is

A $$DC$$ welding power source has a linear voltage-current $$(V$$-$$I)$$ characteristic with open circuit voltage of $$80V$$ and a short circuit current of $$300A.$$ For maximum arc power, the current (in Amperes) should be set as _______________

A butt weld joint is developed on steel plates having yield and ultimate tensile strength of $$500$$ $$MPa$$ and $$700$$ $$MPa,$$ respectively. The thickness of the plates is $$8mm$$ and width is $$20mm.$$ Improper selection of welding parameters caused an undercut of $$3mm$$ depth along the weld. The maximum transverse tensile load (in $$kN$$) carrying capacity of the developed weld joint is _________________