In heavy mining, quarrying, cement manufacturing, and material handling applications, equipment components face continuous gouging, scraping, and sliding abrasion. Hardox 400 and Hardox 450 are the two most prominent quenched and tempered abrasion-resistant (AR) steels globally. While separated by an apparent difference of just 50 Brinell hardness points, their mechanical performance, service longevity, and fabrication behaviors differ significantly.
Wear life does not scale linearly with hardness—it scales exponentially under abrasive sliding conditions. Hardox 450 provides an average of 50% longer wear life than Hardox 400 in pure sliding abrasion:
Delivers a nominal hardness of 400 HBW (range 370–430 HBW). Outstanding bendability, weldability, and structural strength.
Delivers a nominal hardness of 450 HBW (range 425–475 HBW). The industry benchmark for dump truck bodies and excavator buckets.
| Property | Hardox 400 | Hardox 450 |
|---|---|---|
| Brinell Hardness (HBW) | 370 – 430 HBW | 425 – 475 HBW |
| Carbon (C) % max | 0.32% | 0.26% (Modern low-carbon metallurgy) |
| Typical Carbon Equivalent (CET) | 0.28 – 0.38 | 0.29 – 0.37 |
| Charpy-V Impact Energy (-40°C) | 45 Joules (33 ft-lbs) | 40 Joules (30 ft-lbs) |
| Minimum Punch Radius (Bending) | 3.0 x Plate Thickness (t) | 4.0 x Plate Thickness (t) |
Because Hardox 450 has roughly 20% higher yield strength and greater wear endurance than Hardox 400, engineers designing tipper truck bodies and concrete mixer drums frequently substitute an 8 mm Hardox 400 plate with a 6 mm Hardox 450 plate. This 25% weight reduction cuts empty vehicle tare weight, boosts payload capacity, and reduces diesel consumption over hundreds of thousands of haul cycles.
Yes. Both grades can be welded to standard mild or high-strength steel using standard unalloyed or low-alloy GMAW/SMAW consumables (e.g. AWS E7018 or ER70S-6). Preheating is generally not required for plate thicknesses under 20 mm, provided ambient temperature is above 5°C and low-hydrogen practices are maintained.
Hardox 400 and 450 are quenched and tempered martensitic steels. Exposure to temperatures exceeding 250°C (482°F) will temper the microstructure, permanently reducing hardness and wear resistance. For high-temperature abrasive service (up to 500°C), specialized grades like Hardox HiTemp are required.
Remax Forge supplies genuine, fully certified abrasion-resistant wear plates and boiler quality plates cut to custom profiles with complete mill test certificates.