Blade Qualities

Steel grades, hardness and wear patterns

Grade comparison

Wear resistance and impact toughness of blade qualities
Grade Hardness Wear resistance Impact toughness
1.2067 60 HRC 1× 38 J
D2 60 HRC 2× 28 J
M2 64 HRC 2.5× 27 J
M4 64 HRC 3.5× 18 J
ASP 2023 65 HRC 7.5× 38 J
ASP 2053 65 HRC 9× 41 J
Carbide 90 HRA 18× 4 J

Indicative figures. Wear resistance: 1.2067 = 1.

Wear patterns

The standard choice is D2 (1.2379), 58–60 HRC.

Blade edge rounded evenly along its whole length

Evenly rounded, shiny edge

Abrasive wear, the normal wear pattern.

Powder high speed steel ASP 2023, 64–66 HRC.

Blade edge with small chips at irregular intervals

Small chips along the edge

The edge is too hard for the load, or the blade sees impact or vibration.

Lower hardness or a tougher grade.

Blade edge with a large piece broken out

Large chips or a fracture

Foreign object, wrong setting or a loose mounting.

Check the setting and the mounting.

Blade edge with blue and brown temper colours next to it

Edge darkened or blue

Overheating. Blue forms at about 300 °C, and a low-tempered steel has softened by then.

High speed steel M2 (1.3343), 62–65 HRC, or powder steel. They hold their hardness to about 550 °C, low-tempered D2 to about 200 °C.

Blade edge with dark corrosion pits and rust nearby

Corrosion or pitting

Moisture, acidity or cleaning agents.

Stainless grade, 54–58 HRC.

Grades by product

ProductGrades and hardness
Upper knives, shear cuttingASP 2023, ASP 2053, CPM 10V
Lower knives, shear cuttingCemented carbide or powder steel
Crush cutting knivesD2
Core cutting knivesD2, HSS, ASP 2023, ASP 2053
Cross-cutting knivesD2 58–60 HRC, powder steel (ASP 2023, ASP 2053, CPM 10V) 64–66 HRC, cemented carbide
Granulator bladesD2 or powder steel, 56–59 HRC. Also with a carbide edge.
Crusher rotor knives and counter bladesD2 and special steels, 52–59 HRC. Inserts in HSS, ASP or cemented carbide.
Chipper bladesChipper knife steel, 54–58 HRC
Veneer lathe bladesTool steel for softwoods 58–60 HRC, hot work steel for hardwoods 54–58 HRC, HSS edge 64–66 HRC on a tough body
Hammer crusher partsHardox 400, 450, 500 and 600, hardness 400–600 HB

Hardness and composition

GradeDelivery hardnessComposition, weight %Use
Tool steel 1.2067 (102Cr6)58–60 HRCC 1.0 · Cr 1.5When impact is a bigger risk than wear.
D2, 1.2379 (X153CrMoV12)56–64 HRCC 1.55 · Cr 12.0 · Mo 0.7 · V 1.0The standard choice for most cutting work.
High speed steel M2 (HSS), 1.3343 (HS 6-5-2C)62–65 HRCC 0.90 · Cr 4.3 · Mo 5.0 · W 6.5 · V 1.9When the blade runs hot.
High speed steel M4 (HSS), 1.3351 (HS 6-5-4)63–65 HRCC 1.30 · Cr 4.2 · Mo 4.5 · W 5.6 · V 4.0When M2 wears too fast. Grinding is slower.
Powder high speed steel ASP 2023 (HS 6-5-3C)64–66 HRCC 1.28 · Cr 4.0 · Mo 5.0 · W 6.4 · V 3.1Abrasive wear, when D2 is not enough.
Powder high speed steel ASP 2053 (HS 4-3-8)64–66 HRCC 2.48 · Cr 4.2 · Mo 3.1 · W 4.2 · V 8.0Highly abrasive fillers: glass fibre, quartz, grit in recycled material. Grinding is slower.
Stainless steel54–58 HRC–Chemical and food industry, wet environments and exposure to cleaning agents. Moderate wear resistance.
Cemented carbide89–92 HRAWC + CoPure abrasion in a rigid machine, typically the lower knife. Accurate setting, impact-free running.

D2 at different hardnesses

Effect of D2 steel hardness on wear resistance and impact toughness
Hardness Wear resistance Impact toughness
56 HRC 1.0× 68 J
58 HRC 1.1× 43 J
60 HRC 1.15× 28 J
62 HRC 1.2× 20 J
64 HRC 1.3× 14 J
56–58 HRC
Better impact resistance
58–60 HRC
General use
60–64 HRC
Best wear resistance