Grinding abrasives: Aluminium oxide (Al2O3) wheels are chiefly recommended for grinding which of the following materials?

Introduction / Context:
Selecting the proper abrasive is critical for grinding efficiency and surface integrity. Aluminium oxide is the most widely used abrasive for ferrous materials because it fractures in a controlled way and resists chemical reaction with iron at grinding temperatures.

Given Data / Assumptions:

• Abrasive: aluminium oxide (Al2O3).
• Target materials: high speed steel, carbon steel, and wrought iron.
• General-purpose surface or cylindrical grinding conditions.

Concept / Approach:
Aluminium oxide is preferred for steels and wrought iron. Silicon carbide, in contrast, is harder but more brittle and is preferred for non-ferrous metals, hard carbides, and cast iron of certain grades. Therefore, for the list of ferrous materials provided, aluminium oxide is suitable for all.

Step-by-Step Solution:

Verification / Alternative check:
Manufacturer catalogs recommend Al2O3 for tool steels (including HSS), plain carbon steels, and wrought iron products.

Why Other Options Are Wrong:
Limiting the choice to any single listed material understates the broad applicability of aluminium oxide to ferrous metals.

Common Pitfalls:
Confusing aluminium oxide with silicon carbide applications; mixing up the role of grit size with abrasive type.

Final Answer:
All of these