Hardness of each grade
| Grade | Hardness (HBW) | In short |
|---|---|---|
| Hardox 400 | 370 – 430 | The easiest of the three to bend and machine |
| Hardox 450 | 425 – 475 | The common all-rounder |
| Hardox 500 | 470 – 530 | Longest wear life, least forgiving to bend |
Wear life
Against sliding abrasion, such as sand, ore and gravel moving across the plate, wear life rises with hardness. Moving up a grade either makes a liner last longer at the same thickness or lets you use thinner, lighter plate for the same life.
Under heavy impact, such as large rock dropped from height, toughness matters as much as hardness. The softer grades take a hit with less risk of cracking.
Bending and forming
Harder plate needs a larger bend radius and more press force, and springs back more. Hardox 400 bends tightest and 500 needs the most generous radius. SSAB publishes the minimum bend radius for every grade and thickness.
If the part is bent, tell us the plate thickness and the inside radius so we can confirm the grade suits it.
Cutting, drilling and welding
All three can be cut by plasma, laser, waterjet or oxy-fuel. Thick plate may need preheating before thermal cutting to stop the edges cracking.
Drilling and machining get harder as hardness rises, and carbide tooling is the norm on 500. All three are weldable using low-hydrogen consumables and the preheat SSAB recommends for the thickness.
Which grade for which job
- Parts with tight bends or a lot of drilling and machining: Hardox 400
- Bucket shells, tipper and dump bodies, general liners: Hardox 450
- Chute and hopper liners, cutting edges and wear strips under heavy sliding abrasion: Hardox 450 or 500
- Flat liners that are bolted in rather than bent: Hardox 500 for the longest life
These are typical choices, not rules. The material being handled, the impact and the thickness all play a part. Send us the job and we will suggest a grade, or read more about Hardox plate and our wear plate range.
Hardox is a registered trademark of SSAB.