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Duracast NH4 | Duracast DC17

Duracast® NH4 Chrome White Iron

Duracast NH4

Duracast NH4 is an abrasion resistant cast white iron with a long history as a high performing, low-cost material in mining applications. NiHard 4 (NH4) owes its excellent wear and impact resistant properties to its alloying additions and microstructure. Duracast NH4 can be cast in blocks, billets, plates and custom shapes.


Duracast NH4 is cast material produced by Bradken foundries with an automated moulding machine allowing high volume, low cost manufacturing. After casting Duracast NH4 is heat treated to maximise its wear and impact resistance.


NH4 belongs to the white cast iron alloys designated by Australian Standard – AS 2027–2007. The major alloying elements, chromium, nickel and silicon, help to give this material its superior properties. A typical chemical composition is given below:

Carbon 3.0%–3.6%
Silicon 1.5%–2.5%
Manganese 0.3%–0.8%
Chromium 8.0%–10.0%
Nickel 4.5%–6.5%

The microstructure of Duracast NH4 is particularly important in providing good wear performance. After casting Duracast NH4 into the desired shape, a heat treatment cycle is used to transform the softer as-cast microstructure into the hard, long-lasting material needed in abrasive applications. This microstructure consists of eutectic M7C3 carbides in a predominately martensitic matrix.

Bulk Properties
Bulk Hardness 600–700 HV50
Carbide Hardness ≥1200 HV0.5
Volume Fraction of Carbides 20%–25%
Density 7750 kg/m3


Duracast NH4 Manufacturing Process
Duracast NH4 Manufacturing Process
Duracast NH4 Microstructure
Duracast NH4 Microstructure
Duracast NH4 Billet Application
Duracast NH4 Billet Application

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