Tool materials — composition shorthand: In the 18–4–1 high-speed steel designation, identify the correct approximate composition by mass percentage.

Introduction / Context:
High-speed steels (HSS) are denoted by a convenient numeric shorthand indicating key alloy additions that control hot hardness, red hardness, wear resistance, and toughness. Understanding the code helps in selecting tool materials for drilling, milling, and cutting at elevated speeds.

Given Data / Assumptions:

• Designation given: 18–4–1 HSS.
• Order of elements in classic shorthand: tungsten–chromium–vanadium.
• Percentages are approximate mass fractions.

Concept / Approach:
The traditional 18–4–1 series indicates roughly 18% tungsten, 4% chromium, and 1% vanadium in a medium-carbon steel matrix with minor additions (e.g., cobalt in some grades). Tungsten improves hot hardness, chromium contributes to hardenability and oxidation resistance, and vanadium refines carbides for wear resistance.

Step-by-Step Solution:
Map the code: 18 → tungsten ~18%.Next number 4 → chromium ~4%.Final number 1 → vanadium ~1%.Choose the option that lists V 1%, Cr 4%, W 18%.

Verification / Alternative check:
Reference HSS data sheets consistently present the 18–4–1 composition as W ~18%, Cr ~4%, V ~1% with balance iron and carbon.

Why Other Options Are Wrong:
Option (a) inverts vanadium and tungsten; (c) swaps percentages incorrectly; (d) contradicts well-established coding; (e) replaces tungsten with molybdenum, creating a different Mo-HSS family.

Common Pitfalls:
Confusing the order of elements in the shorthand or mixing tungsten-based and molybdenum-based HSS systems.

Final Answer:
vanadium 1%, chromium 4% and tungsten 18%