Alloying effects—role of nickel additions in steels Adding nickel to steel primarily improves which property?

Difficulty: Easy

Correct Answer: corrosion resistance.

Explanation:


Introduction / Context:
Alloying elements profoundly influence the microstructure and properties of steels. Nickel is widely used in structural, stainless, and low-temperature steels. Understanding its dominant effects guides grade selection for corrosive service, cryogenic applications, and general engineering requirements.


Given Data / Assumptions:

  • Nickel additions are at typical alloying levels observed in structural and stainless steels.
  • Comparison is among corrosion resistance, cutting ability, and wear resistance.


Concept / Approach:
Nickel increases toughness, refines grain structure, and improves resistance to corrosion, particularly in combination with chromium in stainless steels. It stabilizes the austenitic phase, enabling good ductility and impact strength at low temperatures. Cutting ability is associated more with high-speed tool steels containing tungsten, molybdenum, vanadium, and cobalt. Wear resistance often correlates with carbides from chromium, vanadium, or high carbon content, not primarily nickel. Therefore, the most direct and characteristic improvement due to nickel is corrosion resistance (and toughness), especially in austenitic stainless steels like 304 and 316.


Step-by-Step Solution:

List typical effects of Ni: corrosion resistance and toughness enhancement.Contrast with cutting ability: dominated by tool steel carbides and cobalt additions.Contrast with wear resistance: improved more by hard carbides and surface treatments.Choose the property most strongly and directly tied to Ni.


Verification / Alternative check:
Materials standards show austenitic stainless steels with significant Ni content offering excellent corrosion resistance. Low alloy Ni steels are chosen for cryogenic and marine environments because of improved corrosion behavior and toughness.


Why Other Options Are Wrong:

  • Cutting ability: not a hallmark of nickel; tool steels rely on other elements.
  • Wear resistance: nickel contributes indirectly via toughness, but primary wear resistance comes from hard phases.
  • All of the above: overstates nickel effects across unrelated properties.


Common Pitfalls:
Assuming an alloying element improves all properties uniformly. Each element has targeted benefits and trade-offs.


Final Answer:
corrosion resistance.

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