Quard 550

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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 the combination of superior hardness and strength, Quard 550 is an optimal choice for the recycling, mining and quarry industry.

Related Standards

This material data has been provided by NLMK Group.

"Typical" values were obtained via a literature search. "Predicted" values were imputed via artificial intelligence technology. While we have placed significant efforts in ensuring data accuracy, "typical" and "predicted" data should be considered indicative and verified by appropriate material testing. Please do contact us if additional information on the the predicted data method is required.
All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.

Ashby charts




Carbon equivalent (CET)

0.46 [-]

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for thickness 6-30 mm

Carbon equivalent (CEV)

0.68 [-]

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for thickness 6-30 mm

Carbon equivalent note

CEV = C+Mn/6+ (Ni+Cu)/15+ (Cr+Mo+V)/5 and CET = C+(Mn+Mo)/10+Ni/40 +(Cr+Cu)/20




1500 - 3100 mm

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PropertyValueTesting StandardComment


7 %

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Hardness, HBW

520 - 580 [-]

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EN ISO 6506-1

1-2 mm below the plate surface once per heat and 40 tonnes

Tensile strength

1750 MPa

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Yield strength

1575 MPa

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Chemical properties



0.005 %

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0.35 %

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1.1 %

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1.6 %

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0.5 %

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1 %

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0.025 %

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0.8 %

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0.01 %

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Technological properties

Application areas

Quard 550 is mainly recommended for the following applications:

  • linings
  • shrouds
  • cutting edges
  • hammers
  • cutters

  • Chemical composition

    The steel is grain refined.

    Delivery condtion

    Our Quard plates are supplied as standard in the shotblasted and primed condition. In order to maintain a good weldability and laser cutting performance, a low zinc silicate primer is applied. Plates can also be delivered unpainted.

    Heat Treatment

    Quard 550 receives its properties by quenching and when applicable by subsequent tempering. The properties of the delivery condition can not be retained after exposure at service or preheating temperatures above 250 °C. Quard 550 is not intended for any further heat treatment.


    Quard 550 offers good machinability with HSS and HSS-Co alloyed drills. The 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.


    Quard 550 is delivered with a unique combination of excellent flatness, tight thickness tolerances and superior surface finish.

    FLATNESSEN 10029: Class N (standard) & Class S
    THICKNESS tolerance-meets and exceeds EN 10029 Class A
    -tighter tolerances upon request
    Shape, length, width tolerancesmeets EN 10029
    SURFACE propertiesexceeds the usual market standards,EN 10163-2 Class B3


    Ultrasonic testing (UT), is applied to secure the plate from discontinuities like inclusions, cracks and porosity. In thickness from 8 mm and up, all plates are UT tested and controlled against class S2, E2, according to EN 10160.

    Thermal cutting and welding

    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. Subsequent to 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).


    Quard 550 can be welded using any of the conventional welding methods, both as manual or automatic. Welding of Quard 550 is recommended to be performed at ambient temperature not lower than +5°C.

    Subsequent to welding, let the welded parts slowly cool down to room temperature (never accelerate the cooling process of the weld).

    If welding using a heat input of 1.7 kJ/mm, preheating is not required in single plate thickness up to 10 mm. The interpass temperature used should not exceed 225 °C.

    Soft weld consumables, giving low hydrogen weld deposits (<= 5 ml/100g), are recommended. The consumable strength should be as soft as the design and wear mode allows.

    In general, the welding recommendation of Quard 550 should be in the accordance to EN-1011.