Buy hardness for the duty, not for the brochure.
What hardness buys — and costs
High hardness extends mold life and holds polish, valuable for optical surfaces and abrasive resins. The cost appears in machining: slower cuts, more tool wear, and often the need for pre-hardened or machined-then-hardened strategies.
The right answer depends on production volume and resin, not on hardness as a status symbol.
Planning the process around it
For high-hardness steels, plan machining before final heat treatment where feasible, budget for electrode and EDM time in detailed areas, and allow realistic delivery schedules.
Discuss duty cycle and resin with your mold base supplier early — the steel choice propagates into every downstream process.
FAQ
Is harder always better for long runs?
For very long runs and abrasive resins, higher hardness usually pays; for short runs, machinability and cost may dominate.
Does polishability track hardness?
Generally higher-hardness, clean steels polish better, but steel cleanliness and structure matter as much as the hardness figure.
Why does delivery time increase with hardness?
Harder steels machine slower and may need heat treatment steps, both of which extend manufacturing time.
All figures above refer to standard product data sheets; final confirmation is subject to written quotation.