Steel 35NC6 - 1.5815 - 35NiCr6 - FE-PL2102

Alloy Construction Steel: 35NC6

This Nickel-Chrome family steel, sometimes referred to as 35NiCr6 (EN 10083-3) or 35NC6 (AIR 9160/C), is characterized by good mechanical strength, good ductility, and a high aptitude for heat treatment. Its composition, rich in nickel and chromium, provides excellent hardenability and uniform properties, even in thick sections. It is therefore used for demanding applications, notably in the aerospace industry, the automotive sector, and heavy-duty mechanical engineering.

1. Chemical Composition

According to the AIR 9160/C specifications, the carbon content typically ranges between 0.30% and 0.37%. The levels of chromium (0.80% to 1.10%) and nickel (1.20% to 1.60%) directly contribute to the steel’s fatigue resistance and good hardenability. Manganese (0.60% to 0.90%) improves strength and toughness, while silicon (0.10% to 0.40%) plays a role in deoxidation and microstructural stability. Finally, the phosphorus and sulfur contents remain very low (≤ 0.025% and ≤ 0.020%, respectively), which limits undesirable embrittlement.

2. Microstructure

In the as-rolled condition, 35NC6 shows a ferrite-pearlite structure that can include complex chromium and nickel carbides. After quenching and tempering, the structure transforms to gain hardness while preserving a ductile core. This balanced microstructure allows it to effectively withstand impact and fatigue. Surface treatments (such as burnishing, etc.) can further enhance toughness and the service life of parts.

3. Mechanical Properties

As mentioned, this grade of steel is known for its core ductility: it has a yield strength (Rp0.2) exceeding 640 MPa, a maximum tensile strength of 1230 MPa, and an elongation above 12%. Ductile yet highly resistant, it can sustain impacts greater than 600 kJ/m² and offers significant hardness (measured between 222 and 363 HB).

4. Industrial Applications

Critical parts made from this alloy benefit from a longer service life, thereby improving operational safety. Due to its good fatigue resistance, ability to withstand high loads, and structural homogeneity, 35NC6 is employed in the manufacture of crankshafts, transmission shafts, gears, or piston rods. It is thus used in the aerospace industry (under AIR 9160/C), heavy-duty mechanical engineering, and shipbuilding, all sectors that require high reliability.