Alloy Steel C40E Round Bar C40E Bars C40E Rods

Product Description

C40E is a European-standard (EN 10083-2) non-alloy medium-carbon engineering steel. The "E" suffix signifies that the material is produced with controlled maximum limits on impurity elements like phosphorus and sulfur, making it cleaner and more responsive to uniform heat treatment compared to standard commercial carbon steel (such as C40).

It is widely distributed as hot-rolled, bright cold-drawn, or turned round bars and rods for structural and mechanical applications requiring greater strength than mild steel.

Technical Specifications

1. Chemical Composition (EN 10083-2)

Because it is a non-alloy steel, its performance stems from carefully balanced carbon and manganese ratios. The low maximum thresholds for sulfur and phosphorus reduce inclusion clusters, lowering the risk of brittle failure during cyclic load operations.

2. Global Material Equivalents

C40E is easily cross-referenced across international standards with minor composition variances:

• Europe (EN / WNr): C40E / 1.1186 (Replaces older DIN Ck40 designation)

• USA (AISI / SAE): 1040 / 1042

• Germany (DIN): Ck40 / Cm40

• Japan (JIS): S40C

• United Kingdom (BS): 080M40 (En8)

• China (GB/T): 40 Steel

Mechanical Properties (Normalized vs. Quenched & Tempered)

The mechanical performance of C40E depends entirely on its final heat-treated state and the cross-sectional thickness of the round bar.

Typical Applications

C40E round bars strike a versatile balance between structural strength and high machinability, making them highly popular across the automotive, hydraulic, and construction sectors:

• Engine Components: Lightly loaded crankshafts, starter ring gears, and robust connecting rods.

• Transmission Hardware: Splined shafts, structural pins, keys, spacer rings, and low-load counter gears.

• Hydraulics & Pneumatics: Main cylinder rams, piston rods, tie rods, and valve manifolds.

• General Engineering: Heavy-duty studs, machinery levers, brackets, and hand tools.

Processing & Fabrication Notes

Surface Treatment Advantage: C40E is an excellent candidate for induction or flame hardening. If your application requires a tough, shock-absorbing interior paired with a wear-resistant exterior, induction treatment can push the surface layer shell hardness up to 55 HRC.

• Machinability: In its normalized or annealed supply condition, C40E scores exceptionally well for cutting, turning, drilling, and tapping on CNC machinery.

• Welding Limitations: Due to its carbon ceiling reaching up to 0.44%, C40E is moderately difficult to weld compared to mild steel. Preheating the bar stock to $150^\circ\text{C} - 250^\circ\text{C}$ is highly recommended for cross-sections over 15mm to eliminate micro-cracking risks in the heat-affected zone (HAZ).