Ceramic slurry is used in making the molds for

In welding process, penetration is increased by

Continuous rails for Indian railways are welded by ........ Welding process.

A resistance welder is rated at $$50$$ $$kVA,$$ at $$50\% $$ duty cycle. Secondary voltage is always constant at $$25$$ volts. If a job requires $$1500$$Amps current, determine the maximum welding time in a total cycle time of $$30$$$$secs$$.