AFNOR AF55C35 Alloy Bar AF55C35 Round Bars AF55C35 Rods

Product Description

AFNOR AF55C35 is a French standard (NF A 33-101) high-quality medium-carbon structural steel. It is a specific nomenclature for the widely used C35 grade. The "AF55" prefix typically refers to the minimum tensile strength category (approx.$550\text{ MPa}$) in a normalized state, while "C35" indicates the carbon content (approx.0.35%).

This material is a balanced "all-rounder" used when you need more strength than mild steel but require better ductility and machinability than high-carbon steels like C45.

1. Chemical Composition

AF55C35 is a non-alloy quality steel with a clean chemical profile to ensure consistent response to heat treatment.

2. Mechanical Properties

Performance depends on whether the bars are Normalized (+N) or Quenched and Tempered (+QT).

3. Key Technical Characteristics

• Surface Hardening: AF55C35 is frequently used for induction or flame hardening. It can achieve a surface hardness of approximately 45–52 HRC, making it excellent for wear-resistant components.

• Machinability: Very high. It is favored for precision machining of rods and bars because it results in a high-quality surface finish with predictable tool wear.

• Weldability:Good to Fair. Unlike higher carbon steels, it can be welded relatively easily, though preheating to 150°C is recommended for thicker sections to prevent stress cracking.

• Toughness: Offers superior impact resistance compared to C45, making it better suited for parts that might experience sudden shocks.

4. Global Equivalents

If you are searching for this material internationally, AF55C35 is virtually identical to:

5. Common Applications

AF55C35 round bars and rods are a staple in general mechanical engineering and automotive manufacturing:

• Automotive: Connecting rods, levers, and small-diameter axles.

• Fasteners: Bolts, studs, and nuts requiring medium strength (Property Class 5.8 or 6.8).

• Machinery: Spindles, drive shafts, spacers, and keyed shafts.

• Agriculture: Pivot pins and bushings for tractors and harvesters.

Available Stock Conditions

• Round Bars: Available from 3mm to 400mm in diameter.

• Rods: Often supplied in Cold Drawn or Centerless Ground finishes (h9/h11 tolerances) for direct use in automatic lathes.

• Finish: Black (as-rolled), peeled, or polished.