The Quard abrasion resistant plates are delivered with hardness of 400 HB (Quard 400), 450 HB (Quard 450) and 500 HB (Quard 500), with thicknesses ranging from 3.2 mm to 64 mm and widths from 1,500 to 3,100 mm.

They are designed for construction and mining equipments (excavators, dump trucks, bulldozers, hoppers, mixers, etc.), as well as for machinery in very demand industries (recycling, agriculture,etc). The use of Quard may result in product lifetime being more than tripled when compared to products made from standard grades of steel.

Description and applications

Quard is a martensitic abrasion resistant steel with an average hardness of 400, 450 and 500 HBW. Due to its versatility in terms of high toughness, good cold formability and excellent weldability, Quard combines outstanding workshop performance and long lasting wear resistance.
Quard is recommended for the following applications:
  • mining and earthmoving machinery;
  • dump truck and car bodies;
  • cement mixer drum bodies;
  • waste bins, trash containers;
  • buckets, knives;
  • feeders, trolleys, screw conveyors.

Dimensions

The following Quard product mix is currently available:
Thickness mm Width
Quard 400
4-50 mm
Quard 450
4-64 mm
1,500–3,100 mm
Quard 500
4-40 mm

Technical Characterstics

Hardness guarantee
Hardness
Quard 400
HBW = 370–430
Quard 450
HBW = 420–480
Quard 500
HBW = 470–530
Brinell hardness test, HBW according to EN ISO 6506-1, is performed 1–2 mm below the plate surface once per heat and 40 tonnes.

Other mechanical properties (typical values)

V-notch impact test (longitudinal at –40°C) Yield strength (MPa) Tensile strength Transverse testing (MPa) Elongation A5 (%)
Quard 400
40 J
1,160
1,300
10
Quard 450
35 J
1,250
1,400
10
Quard 500
30 J
1,500
1,700
8

Chemical Composition

Steel is grain refined
Quard 400

Laddle Analysis,%max
Plate Thickness C Si Mn P S Cr Ni Mo B
4-25.4 mm 0.16 0.60 1.40 0.025 0.010 0.50 0.10 0.25 0.005
25.41–40 mm 0.17 0.60 1.60 0.025 0.010 1.15 0.10 0.30 0.005
40.01–50 mm 0.17 0.60 1.60 0.025 0.010 1.30 0.50 0.50 0.005

Quard 450

Laddle Analysis,%max
Plate Thickness C Si Mn P S Cr Ni Mo B
3.2–20 mm 0.20 0.60 1.40 0.025 0.010 0.20 0.10 0.25 0.005
20.1–40 mm 0.21 0.60 1.60 0.025 0.010 0.75 0.10 0.30 0.005
40.01–64 mm 0.23 0.60 1.60 0.025 0.010 1.30 0.50 0.50 0.005

Quard 500

Laddle Analysis,%max
Plate Thickness C Si Mn P S Cr Ni Mo B
4–40 mm 0.30 0.80 1.60 0.025 0.010 1.00 1.00 0.50 0.005

Carbon equivalent

Carbon equivalent, typical values, %
Plate Thickness CEV(1) CET(2)
Quard 400
4–8 mm 0.36 0.25
8.01–20 mm 0.40 0.28
20.01–25.4 mm 0.45 0.29
25.41–40 mm 0.57 0.33
40.01–50 mm 0.64 0.36
Quard 450
3.2–7.99 mm 0.41 0.30
8–20 mm 0.41 0.32
20.01–40 mm 0.56 0.37
40.01–64 mm 0.64 0.40
Quard 500
4–20 mm 0.57 0.40
20.01–40 mm 0.61 0.43

Tolerances and surface properties

Quard offers a unique combination of excellent flatness, tight thickness tolerances and superior surface finish.
Grade
Feature Quard 400 Quard 450 Quard 500
Flatness EN 10029: class N (standard) and class S
Thickness tolerance Meet and exceed EN 10029
Tighter tolerances upon request
Shape, length, width and thickness tolerances Comply with EN 10029
Surface properties Exceed existing market standards EN 10163-2 Class B3

Heat treatment

Quard 400, Quard 450 and Quard 500 receive their properties through quenching and when applicable with subsequent tempering. For these properties to be retained, Quard plates should not be used in applications requiring heat treatment and service temperatures above 250°C. Quard 400, Quard 450 and Quard 500 is not intended for any additional heat treatment.

Ultrasonic testing

Ultrasonic testing (UT) is used to identify such discontinuities as inclusions, cracks and porosity. In thickness from 8 mm and higher, all plates are UT tested and controlled against class S2, E2 in accordance with EN10160.

General processing guidelines

To obtain optimal processing productivity for Quard 400, Quard 450 and Quard 500, it is essential to use the recommended procedures and tools given below

Thermal cutting

Plasma and flame cutting can be performed without the need for preheating plates in thicknesses up to 20 mm, provided the ambient temperature is above 0°C. After cutting, plates should be cooled down to room temperature. Slow cooling reduces the risk of cut edge cracking. Never use accelerated cooling

Cold forming

Quard grades are well suited for cold forming. The minimum recommended R/t ratios for Quard bending are given in the table below:
Thickness (mm) Transverse
to rolling (R/t) 		Longitudinal
to rolling (R/t)		 Trans. width (W/t) Long. width (W/t)
Quard 400 t < 8.0 2.5 3.0 8 10
8 ≤ t < 20 3.0 4.0 10 10
t ≥ 20.0 4.5 5.0 12 12
Quard 450 t < 8.0 3.5 4.0 10 10
8 ≤ t < 20 4.0 5.0 10 12
t ≥ 20.0 5.0 6.0 10 12
Quard 500 t < 8.0 3.5 4.5 10 12
8 ≤ t < 20 4.5 5.0 12 14
t ≥ 20.0 6.0 7.0 16 18

Welding

Quard shows good weldability due to low carbon equivalent. It can be welded using any conventional welding method,both manual and automatic.

Quard welding is recommended at ambient temperatures not lower tan +5°С.

After welding, the welded parts should be left to cool down to room temperature. Never use accelerated cooling.When welding plates in thicknesses up to 12 mm using a heat input of 1.7 kJ/mm, preheating is not required. Interpass temperatures used should not exceed 225˚C.

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

In general, welding recommendations for Quard plates should comply with EN-1011.

Machining

Quard 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.