What is the primary difference between high-speed steel (HSS) and carbide cutting tools?

What is the primary difference between high-speed steel (HSS) and carbide cutting tools?

• A. Carbide is cheaper and easier to sharpen than HSS.
• B. Carbide is harder and holds an edge longer but is more brittle; HSS is tougher and resharpenable but wears faster.
• C. HSS is harder and holds an edge longer but is more brittle; Carbide is tougher and resharpenable but wears faster.
• D. HSS is softer but resists heat better; Carbide is brittle.

Answer: (B)

The main idea is comparing the inherent material properties that affect cutting performance: hardness, edge retention, toughness, and how easily the tool can be sharpened. Carbide tools are much harder than high-speed steel, so they stay sharp longer and can cut at higher speeds with less wear. But that same hardness makes them brittle, so they’re more prone to chipping if they’re struck or subjected to interrupted cuts, and sharpening them isn’t something you do with ordinary shop tools. High-speed steel is tougher and more ductile, so it resists shock and can be re-sharpened easily, but it wears faster at high speeds and temperatures because it doesn’t hold an edge as long. That’s why the best description is that carbide is harder and holds an edge longer but is more brittle; high-speed steel is tougher and resharpenable but wears faster. The other statements are flawed because they either misstate which material is harder or tougher, or they claim heat resistance or sharpening ease that doesn’t match these materials.

The main idea is comparing the inherent material properties that affect cutting performance: hardness, edge retention, toughness, and how easily the tool can be sharpened. Carbide tools are much harder than high-speed steel, so they stay sharp longer and can cut at higher speeds with less wear. But that same hardness makes them brittle, so they’re more prone to chipping if they’re struck or subjected to interrupted cuts, and sharpening them isn’t something you do with ordinary shop tools. High-speed steel is tougher and more ductile, so it resists shock and can be re-sharpened easily, but it wears faster at high speeds and temperatures because it doesn’t hold an edge as long.

That’s why the best description is that carbide is harder and holds an edge longer but is more brittle; high-speed steel is tougher and resharpenable but wears faster. The other statements are flawed because they either misstate which material is harder or tougher, or they claim heat resistance or sharpening ease that doesn’t match these materials.