QUARD 550
Abrasion Resistant Steel Plate
1. Steel description and applications
Quard 550 is a martensitic abrasion-resistant steel with an average hardness of 550 HBW. Its very high resistance to abrasive wear makes it ideal where long service life is required. With a combination of superior hardness and strength, Quard 550 is an optimal choice for the recycling, mining and quarry industry.
Recommended applications:
- linings, shrouds
- cutting edges & hammers
- cutters, chutes
- transport/recycling equipment, quarry machinery
2. Technical characteristics
Hardness guarantee (HBW): 520 – 580
Brinell hardness, test HBW, 10 mm ball / 3000 kgf. Measured at ¼ thickness.
Other mechanical properties (typical values)
| Yield Strength (MPa) | Tensile Strength (MPa) | Elongation A5 (%) |
|---|---|---|
| 1575 | 1750 | 7 |
3. Dimensions
Supplied in the following range:
Thickness: 6 – 30 mm | Width: 1500 – 3100 mm
For extensions of the dimensional program please check the website or contact your local representative.
4. Flatness, tolerances & surface properties
| Feature | Norm |
|---|---|
| Flatness | EN 10029 — Class S (Standard) |
| Thickness tolerances | Meets & exceeds EN 10029 Class A; tighter tolerances upon request |
| Shape, length, width tolerances | Meets EN 10029 |
| Surface properties | Exceeds usual market standards; EN 10163-2 Class B3 |
5. Delivery conditions
Plates are supplied as standard in the shotblasted (SA 2.5) and primed condition. To maintain good weldability & laser cutting performance, a low-zinc silicate primer (e.g., Hempel 15 My) is applied (light green). Plates can also be delivered unpainted.
6. Heat treatment
Quard 550 obtains its properties by quenching and, when applicable, by subsequent tempering. Properties in the delivery condition cannot be retained after exposure at service or preheating temperatures above 250 °C. Further heat treatment is not intended.
7. Ultrasonic testing
Ultrasonic testing (UT) is applied to secure the plate from discontinuities like inclusions, cracks and porosity. For thickness from 8 mm and up, all plates are UT-tested and controlled against class S2, E2 according to EN 10160.
8. General processing recommendations
Thermal cutting
Plasma and flame cutting can be performed without the need for preheating in thicknesses up to 20 mm, provided the ambient temperature is above 0 °C. After cutting, let the cut parts slowly cool down to room temperature. A slow cooling rate will reduce the risk of cut-edge cracking (never accelerate the cooling of the parts).
Cold forming (minimum bend radii)
| Thickness (t, mm) | Transverse R/t | Longitudinal R/t | Min. flange width (W/t) | Min. bend width (B/t) |
|---|---|---|---|---|
| t ≤ 8.0 | 3.5 | 4.5 | 12 | 12 |
| 8.1 – 20 | 4.0 | 5.0 | 12 | 12 |
| t ≥ 20 | 5.5 | 6.0 | 12 | 12 |
Bending along rolling direction = longitudinal; across rolling direction = transverse.
Welding
Weld at ambient temperature not lower than +5 °C. Using a heat input of about 1.7 kJ/mm, preheating is not required in single-plate thicknesses up to 10 mm. Interpass temperature should not exceed 225 °C. Use soft weld consumables (low-hydrogen, ≤ 5 ml/100 g). Consumable strength should be as soft as the design and wear mode allows. Follow EN-1011 guidance.
Machining
Quard 550 offers good machinability with HSS and HSS-Co alloyed drills. Feed rate and cutting speed have to be adjusted to the high hardness of the material. Face milling, counter-boring and countersinking are best performed using tools with replaceable cemented-carbide inserts.
Chemical composition — max. ladle analysis (%)
| C | Si | Mn | P | S | Cr | Ni | Mo | B |
|---|---|---|---|---|---|---|---|---|
| 0.35 | 0.80 | 1.60 | 0.025 | 0.010 | 1.10 | 0.10 | 0.50 | 0.005 |
Carbon equivalent (typical values, %)
| Plate thickness | CEV | CET |
|---|---|---|
| 6 – 30 mm | 0.68 | 0.46 |
CEV = C+Mn/6+Cr+Mo+V/5+Ni+Cu/15 | CET = C + (Mn+Mo)/10 + (Cr+Cu)/20 + Ni/40