The alloys we cast
Wear parts fail in two different ways: they abrade away, or they break. Hardness resists the first and works against the second, so every alloy below is a position on that trade-off. Which one suits you depends on your feed, not on which is hardest.
High chrome white iron
Hard chromium carbides in a martensitic matrix. The default choice for clean, abrasive feed such as limestone, dolomite and river gravel, but brittle where tramp metal appears.
| Grade | Typical composition | Hardness | Suited to |
|---|---|---|---|
| ASTM A532 Cl. II Type B (15Cr-3Mo) | 14–18% Cr, 2.5–3.5% Mo, 2.4–3.0% C | 58–64 HRC | General high-abrasion impact crushing |
| ASTM A532 Cl. II Type D (20Cr-Mo) | 18–23% Cr, 1.5% Mo max, 2.0–3.3% C | 58–63 HRC | Abrasive limestone and secondary duty |
| ASTM A532 Cl. III Type A (25Cr) | 23–30% Cr, 1.5% Mo max, 2.0–3.3% C | 56–62 HRC | Highest abrasion, corrosive or wet feed |
Austenitic manganese steel
Hadfield steel. Leaves the foundry soft at around 220 BHN and work-hardens past 500 BHN at the struck face while the core stays tough. The alloy for impact, rebar and uncrushables.
| Grade | Typical composition | Hardness | Suited to |
|---|---|---|---|
| ASTM A128 Grade A | 1.05–1.35% C, 11.0–14.0% Mn | 200–229 BHN as-cast, 500+ BHN work-hardened | Standard high-impact duty |
| ASTM A128 Grade B-3 | 0.9–1.05% C, 11.5–14.0% Mn | 200–229 BHN as-cast, 500+ BHN work-hardened | Heavier sections, improved toughness |
| ASTM A128 Grade C | 1.05–1.35% C, 11.5–14.0% Mn, 1.5–2.5% Cr | 220–250 BHN as-cast | Where extra initial hardness is needed |
| ASTM A128 Grade E-2 | 0.7–1.3% C, 11.5–14.0% Mn, 1.8–2.1% Mo | 200–229 BHN as-cast | Heavy sections, faster work-hardening |
A manganese casting that arrives already hard has usually not been solution treated correctly. Correctly treated, it is also essentially non-magnetic.
Martensitic and composite grades
Between the two at 45–52 HRC. Where the duty genuinely mixes impact and abrasion, as much recycled concrete work does, a martensitic bar often gives the best result even though it wins neither category outright.
| Grade | Typical composition | Hardness | Suited to |
|---|---|---|---|
| Low-alloy martensitic steel | 0.3–0.5% C, Cr-Ni-Mo alloyed | 45–52 HRC | Mixed impact and abrasion |
| Martensitic / manganese composite | Hard martensitic face, austenitic Mn body | 50 HRC face, tough core | Reinforced concrete and recycling |
Ni-hard, alloy and heat-resistant steel
- Ni-hard white iron (ASTM A532 Class I) 550–650 BHN. Slurry pumps, pulp refiner segments, mill liners and abrasion-dominated duty in mining, cement and paper plants.
- Alloy steel Cr-Ni-Mo alloyed grades for components needing strength and toughness rather than maximum surface hardness.
- Heat-resistant steel Sintering plant grate bars, furnace beams, baffles, kiln end rings and cooler grates that run at temperature rather than under abrasion.
Composition ranges above are quoted against the published standard they belong to. The actual analysis for your heat is issued with the castings.