The GATE Grind

GATE 2024 MT – Question 49

Manufacturing Processes · Welding and joining · 2 marks · Multiple select

Which of the following statements is/are correct for joining processes?

  1. In soldering and brazing, the filler melts below the melting point of the metals joined.
  2. In tungsten inert gas welding, tungsten is the filler material.
  3. Friction welding is a solid-state joining process.
  4. Thermit welding uses $\mathrm C_2H_2(g)+\tfrac52\mathrm O_2(g)\to2\mathrm{CO}_2(g)+\mathrm H_2O(g)+\text{Heat}\ (\Delta H)$.

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Correct answer: (A) In soldering and brazing, the filler melts below the melting point of the metals joined.; (C) Friction welding is a solid-state joining process.

Explanation

Soldering and brazing melt a lower-melting filler while retaining solid parent metals, so A is true.

Friction welding is a solid-state process, so C is true.

TIG uses nonconsumable tungsten, not tungsten filler; thermit welding uses an aluminothermic oxide reduction rather than acetylene combustion. **A,C**.