Which coolant function is essential when cutting steel to prolong tool life?

Which coolant function is essential when cutting steel to prolong tool life?

• A. Increases heat
• B. Lubrication reduces friction
• C. Changes color
• D. Prevents rust completely

Answer: (B)

When cutting steel, the tool edge suffers from heat and wear due to metal-to-metal contact. A coolant’s essential job is to cool and lubricate the workpiece–tool interface. The key benefit here is lubrication reducing friction: a lubricating film between the tool and steel lowers wear, keeps the edge sharper longer, and reduces the heat generated by sliding contact. That direct effect on tool life—less wear and lower temperatures—makes it the most important function among the options. The other choices don’t help tool life in the same way: increasing heat accelerates wear; changing color is irrelevant to performance; and while coolant can help limit rust, it won’t guarantee complete rust prevention and that effect isn’t what mainly prolongs tool life in cutting.

When cutting steel, the tool edge suffers from heat and wear due to metal-to-metal contact. A coolant’s essential job is to cool and lubricate the workpiece–tool interface. The key benefit here is lubrication reducing friction: a lubricating film between the tool and steel lowers wear, keeps the edge sharper longer, and reduces the heat generated by sliding contact. That direct effect on tool life—less wear and lower temperatures—makes it the most important function among the options. The other choices don’t help tool life in the same way: increasing heat accelerates wear; changing color is irrelevant to performance; and while coolant can help limit rust, it won’t guarantee complete rust prevention and that effect isn’t what mainly prolongs tool life in cutting.