The GATE Grind

GATE 2023 MT – Question 53

Physical Metallurgy · Corrosion · 2 marks · Multiple select

Choose the correct statement(s) in the context of fusion welding of austenitic stainless steel containing about 0.06 wt.% carbon.

  1. Corrosion resistance of heat affected zone is poorer than base material.
  2. Corrosion resistance of heat affected zone is superior than fusion zone.
  3. Corrosion resistance of heat affected zone is same as fusion zone.
  4. Corrosion resistance is same for fusion zone, heat affected zone, and base material.

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Show answer and explanation

Correct answer: (A) Corrosion resistance of heat affected zone is poorer than base material.

Explanation

The heat-affected zone can spend time in the sensitization range, precipitating chromium carbides at grain boundaries and leaving adjacent regions chromium-depleted. Its intergranular corrosion resistance can therefore be poorer than the unaffected base material.

Thus **A**; equality across all regions is not generally justified.