550HBW quenched and tempered fine grain wear resistant structural
steel plate
550HBW WEAR RESISTANT STEEL is a wear resistant steel with a
nominal hardness of 550 HBW in delivery condition ex works.
550HBW WEAR RESISTANT STEEL is preferentially used by the customers
where very high resistance to wear is required. Examples of
application are extremely stressed parts in earth moving machines,
conveyors, crushers and recycling plants.
Product description
Designation and range of application
550HBW WEAR RESISTANT STEEL can be delivered in thicknesses from 10
mm (0.4 in.) to 51 mm (2 in.) and in widths up to 3 300 mm (130
in.).
Chemical composition
For the ladle analysis, the following limiting values in % are
applicable, max.:
| C | Si | Mn | P | S |
| 0.37 | 0.70 | 1.60 | 0.025 | 0.010 |
Depending on the thickness, the following alloying elements may be
used singly or in combination, max.:
| Mo | Ni | Cu | Cr | V | Nb | B |
| 0.60 | 1.40 | 0.30 | 1.50 | 0.08 | 0.05 | 0.005 |
The steel is fully killed and fine grain treated.
Delivery condition
The plates are water quenched or water quenched and tempered under
controlled conditions.
Mechanical properties in the delivery condition
Hardness
Brinell surface hardness at room temperature: 520 – 580 HBW
Charpy-V impact test on longitudinal specimens (indicative values
for 20 mm plate thickness)
Charpy impact energy: 25 J at -20 °C (-4 °F).
Testing
Brinell surface hardness tested once per heat and 40 t.
Identification of plates
Unless otherwise agreed the marking is carried out via steel stamps
with at least the following information:
- steel grade (550HBW WEAR RESISTANT STEEL)
- heat number
- number of mother plate and individual plate
- the manufacturer’s symbol
- inspection representative’s sign
Processing
The entire processing and application techniques are of fundamental
importance to the reliability of the products made from this steel.
The user should ensure that his design, construction and processing
methods are aligned with the material, correspond to the state of
the art that the fabricator has to comply with and are suitable for
the intended use. The customer is responsible for the selection of
the material. Recommendations regarding job safety in accordance
with national rules should be observed while considering the higher
strength and high hardness.
Cold forming
550HBW WEAR RESISTANT STEEL can be cold formed to only a limited
extend because of its high hardness and strength. In case of such
applications please contact the customer service.
Hot forming / Heat treatment
Since 550HBW WEAR RESISTANT STEEL obtains its hardness by
accelerated cooling from the austenitizing temperature, hot forming
without major hardness loss is only possible if a renewed quenching
treatment is carried out after forming. However, the hardness
achieved by means of such a treatment may differ from that measured
in the delivery condition. This is due to the fact that the cooling
conditions at the fabricator’s works are generally less adequate
than those available during plate production.
The steel can be heated to about 250 °C (482 °F) without any
substantial drop in hardness.
Flame cutting and welding
For flame cutting, the following minimum preheating temperature
should be observed: 175 °C (347 °F) for all thicknesses.
After flame cutting, attention should be paid to a slow cooling,
e.g. by using thermal-blankets. This will reduce the risk of
hydrogen-induced cracking.
When using ferritic filler materials, attention should be paid to
very low hydrogen content and the following preheating temperatures
have to be observed: 150 °C (302 °F) for plate thicknesses up to 15
mm and 200 °C (392 °F) for thicker plates.
When using soft austenitic filler materials, a preheating
temperature of 50 °C (122 °F) is normally sufficient. To avoid a
hardness loss, the preheat and interpass temperature for flame
cutting and welding irrespective of the applied process should not
exceed 250 °C (482 °F).
For manual arc welding, basic coated rods with very low residual
moisture should be used (and dried if necessary according to the
manufacturer’s instructions).
Machining
550HBW WEAR RESISTANT STEEL can be machined by using sharp carbide
tools in spite of its very high hardness. It should be ensured that
adequate heavy machine tools, adequate feed and cutting speeds are
applied.
General technical delivery requirements
Unless otherwise agreed, the general technical delivery
requirements in accordance with EN 10021 apply.
Tolerances
Unless otherwise agreed, the tolerances will be in accordance with
EN 10029, with class A for thickness.
Surface quality
Unless otherwise agreed, the specifications will be in accordance
with EN 10163-2, class A2.
General note
If special requirements, which are not covered in this material
data sheet, are to be met by the steel due to its intended use or
processing, these requirements are to be agreed before placing the
order.
Production process
