AFNOR XC42H1 Alloy Steel Bar XC42H1 Round Bars XC42H1 Rods

Product Description

AFNOR XC42H1 (WNr. 1.1191 variant) is a high-quality, medium-carbon engineering steel. The "H1" suffix indicates a specific control over hardenability and grain size, often required for precision automotive and mechanical components that undergo induction or flame hardening.

It is essentially a refined version of the standard XC42 (equivalent to C45), offering more predictable results during heat treatment and superior mechanical consistency across different batches.

Technical Profile: AFNOR XC42H1

Chemical Composition (%)

As a medium-carbon "special" steel, XC42H1 balances strength and ductility. The H1 designation ensures that impurities like Phosphorus and Sulfur are kept to a minimum to prevent brittleness.

Mechanical Properties (Condition QT - Quenched & Tempered)

XC42H1 is designed to be heat-treated to achieve high structural strength.

• Tensile Strength ($R_m$): 630 a 850 MPa

• Yield Strength ($R_e$): $\ge 370$ MPa

• Elongation ($A_5$): $\ge 14\%$

• Impact Strength (Charpy V): $\ge 25$ J

• Surface Hardness: Can achieve 55 a 60 HRC after localized induction hardening.

Key Characteristics

• Enhanced Hardenability (H1): The "H1" control means the steel responds more uniformly to quenching. This is critical for parts like gears or shafts where consistent hardness depth is required to prevent premature wear or fatigue.

• High Strength: Offers significantly higher load-bearing capacity than low-carbon grades (like XC18), making it suitable for structural engine and machine parts.

• Induction Hardening: This is the primary reason for choosing XC42H1. It responds exceptionally well to surface hardening, allowing for a hard, wear-resistant outer shell and a shock-absorbing core.

• Machinability: Good machinability in the normalized or annealed state. It is considered the "baseline" for machining among medium-carbon steels.

Common Applications

XC42H1 round bars and rods are utilized for heavy-duty components:

• Power Transmission: Gears, pinions, and splined shafts.

• Engine Components: Crankshafts, connecting rods, and cam followers.

• Tooling: Low-precision hand tools, hammers, and pliers.

• General Machinery: Guide rods, axles, bolts, and heavy-duty spindles.

Global Designations & Equivalents

Heat Treatment Parameters

• Normalizing: $840A \text{C} a 880A \text{C}$ (Air cool).

• Hardening: $820A \text{C} a 860A \text{C}$ (Water or Oil quench).

  • Water quenching is common for simple shapes, but oil is preferred for the H1 grade to minimize the risk of quenching cracks.

• Tempering: $550A \text{C} a 660A \text{C}$ (Adjusted based on target tensile strength).

• Induction Hardening: Localized heating followed by immediate quenching to achieve high surface hardness.