UPSC Prelims 1996 · General Studies
Question 129: Science and Technology
Which one of the following elements is alloyed with iron to produce steel which can resist high temperatures and also have high hardness and abrasion resistance?
AnswerThe answer is (d).
Tungsten alloyed with iron gives high-speed tool steel that keeps its hardness and resists abrasion at high temperatures, as needed in cutting tools. Chromium mainly adds corrosion resistance and hardness (stainless steel), nickel adds toughness and strength, and aluminium is not the alloying element for such steel. Remember: tungsten - high-speed steel.
Why each option is right or wrong
- (a) Aluminium is not the alloying element for hard heat-resistant tool steel.
- (b) Chromium mainly adds corrosion resistance and hardness, as in stainless steel.
- (c) Nickel adds toughness and strength.
- (d) Right: tungsten gives hardness and abrasion resistance at high temperatures.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1996, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.