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When should I choose a high-toughness grade (YG15 / YG20)?

When the part takes impact, shock or thermal cycling — not just abrasion. This is the classic failure pattern: a hard, low-binder grade wears well but chips or cracks when the valve slams, the punch strikes, or the die is loaded unevenly. If your current part fails by chipping or fracture rather than smooth wear, toughness — not hardness — is the problem.

The trade-off: more cobalt binder absorbs impact energy and stops cracks from propagating. You give up some hardness, and the part survives service that would shatter a hard grade:

• YG6 / YG6X — high hardness (HRA 90–91.5), low toughness: chipping, edge breakage
• YG8 — balance for moderate duty (HRA 89.5)
• YG15 / YG20 — lower hardness (HRA 82–87.5), high toughness: survives impact and shock

Choose a high-toughness grade if any of these apply: impact or shock loading (valves slamming shut, punches striking, dies closing under load) · current failure mode is chipping or fracture rather than smooth wear · thermal or mechanical cycling · vibration or misalignment. Typical parts: valve seats and seat rings for high-pressure-drop service (YG15C class), sealing rings, stamping and cold-heading die inserts (YG20 class), special shapes under repeated impact.

Send a drawing or photo with the operating conditions and — if you know it — the current failure mode. That last piece often decides the grade. We'll confirm the grade and quote within 1–2 business days.