A quenched and tempered martensitic steel plate specified by surface hardness (typically 400-640 HBW) rather than by yield strength, used wherever sliding or impact abrasion wears a component out.
Armor Steel
High-hardness quenched and tempered plate (typically 480-600 HBW) whose acceptance is a ballistic firing test, not only a hardness and tensile test.
Ballistic Limit (V50)
The impact velocity at which a given projectile has a 50% probability of completely perforating a given plate — the standard statistical measure of ballistic performance.
Bend Radius (R/t)
The minimum inside radius, expressed as a multiple of plate thickness, to which a grade can be cold formed without cracking.
Brinell Hardness (HBW)
The hardness value obtained by pressing a tungsten carbide ball into the steel under a defined load and measuring the indentation, reported in HBW to DIN EN ISO 6506-1.
Carbon Equivalent (CEV)
A single number combining carbon and alloy content that indicates how readily the heat affected zone will harden and therefore how much preheat a weld needs.
EN 10029 Thickness Tolerance
The European standard governing tolerances on thickness, width, length and flatness for hot rolled plate 3 mm and over.
EN 10204 3.1 Certificate
An inspection certificate issued by the manufacturer's independent inspection representative, confirming the delivered plate meets the order against actual test results for that heat.
EN 1522
The European standard for bullet resistance of windows, doors, shutters and blinds, classified FB1 to FB7 plus FSG (no splintering).
Flatness (EN 10029)
The permitted deviation of a plate from a flat plane, classified in EN 10029 by steel type and measuring length — Class N is the normal requirement for cut-to-shape plate.
Gouging Abrasion
High-stress wear in which coarse, sharp material is forced into the surface and ploughs metal away, as in a crusher jaw or a rock-loaded bucket lip.
Heat Affected Zone (HAZ)
The band of parent plate beside a weld or cut that has been heated enough to change its structure and properties without melting.
High Tensile / High Strength Steel (HSLA & Q+T)
Plate specified by minimum yield strength — typically 460 to 900 MPa — used to cut structural weight rather than to resist wear.
Hydrogen Induced Cracking
Delayed cracking in or near a weld caused by dissolved hydrogen, a hard microstructure and residual stress acting together, sometimes appearing days after welding.
Impact Toughness (Charpy V)
The energy in joules absorbed by a notched specimen broken at a stated temperature — the standard measure of a plate's resistance to brittle fracture.
Impact Wear
Wear driven by repeated high-energy impacts rather than sliding contact, where toughness and resistance to cracking matter as much as hardness.
Lamination
A planar internal separation lying parallel to the plate surface, originating from non-metallic inclusions or porosity elongated during rolling.
Liner Life
The service time or tonnage a wear component achieves before replacement — the only commercially meaningful measure of a wear plate's performance.
NIJ 0108.01
The US National Institute of Justice standard for ballistic resistant protective materials, which defines Levels I to IV by projectile, mass and strike velocity.
OEM Contract Manufacturing
Production carried out by an independent mill to the buyer's written specification, chemistry limits and acceptance criteria, released under the buyer's brand.
Payload Gain
The extra paying load a truck or body can carry after heavy mild steel liners are replaced with thinner, harder wear plate.
Plasma & Laser Cutting
Thermal cutting processes used to profile plate, each leaving a narrow hardened and heat affected cut edge.
Preheat Temperature
The minimum temperature a joint is raised to before welding, to slow cooling, let hydrogen diffuse out and avoid a brittle heat affected zone.
Quenched & Tempered (Q+T)
The heat-treatment route in which plate is austenitised, rapidly water quenched to form martensite, then tempered to recover toughness at the target hardness or yield strength.
Roller Quenching
Quenching in which the hot plate is carried between driven rolls that spray water on both faces, cooling and flattening the plate simultaneously.
STANAG 4569
The NATO standardisation agreement defining protection levels for occupants of logistic and light armoured vehicles, Levels 1 to 6 for kinetic energy, artillery and mine threats.
Spalling
The detachment of fragments from the unexposed (back) face of a plate on impact, even where the projectile does not perforate.
Tempering
Reheating quenched plate below the transformation temperature to relieve quench stresses and trade a controlled amount of hardness for toughness.
Ultrasonic Testing (EN 10160)
Volumetric examination of plate for internal discontinuities and lamination, classified in EN 10160 by body and edge quality class (e.g. S0/E0).
Yield Strength (Rp0.2)
The stress at which plate shows 0.2% permanent strain — the design strength used for structural plate.