1.3820 Cr-Mn-N Steel Round Bar,Rods

Product Description

1.3820 is a high-alloyed, non-magnetic austenitic steel designated as X12CrMnN18-11. It is primarily engineered for the electrical and power generation industries, specifically for components that must remain entirely non-magnetic while under high mechanical stress.

While similar to 1.3813, the 1.3820 grade often features a slightly adjusted chemistry to optimize for high-yield strength and stability in large-scale structural applications.

1. Chemical Composition (Typical)

The alloy utilizes high levels of Manganese and Nitrogen to stabilize the austenite phase without the need for high Nickel content.

2. Physical and Mechanical Properties

1.3820 round bars are noted for their consistent performance across extreme environmental conditions.

• Magnetic Permeability: $\mu \leq 1.01$. This grade is effectively "transparent" to magnetic fields, which is essential for preventing energy loss through eddy currents in electrical machinery.

• Yield Strength ($R_{p0.2}$): $\geq 400$ MPa in the solution-annealed condition. This is significantly higher than standard 304 ($1.4301$) or 316 ($1.4401$).

• Tensile Strength ($R_m$): $750 – 950$ MPa.

• Toughness: High notch impact strength even at cryogenic temperatures, ensuring the material does not become brittle.

3. Key Applications

Because 1.3820 effectively eliminates magnetic interference, its round bars and rods are widely used in:

• Power Plants: Retaining rings for generators, where the material must withstand massive centrifugal forces without becoming magnetized.

• Transformer Construction: Clamping bolts, tie rods, and structural supports where magnetic flux would otherwise cause induction heating in carbon steel parts.

• Naval & Defense: Non-magnetic components for sensitive detection equipment and structural parts for specialized vessels.

• Scientific Research: Support frames and vacuum chambers for high-energy physics experiments involving large magnets (e.g., fusion reactors).

4. Comparison: 1.3820 vs. 1.3813

While these two grades are closely related "sister" alloys, 1.3820 is generally preferred when:

• Higher Nitrogen solubility is required to reach slightly higher strength levels.

• Thermal stability during welding or high-temperature processing is a priority for the specific component geometry.

5. Fabrication & Processing Tips

• Machinability: Like most Cr-Mn-N steels, 1.3820 has a very high work-hardening rate. If the cutting tool "dwells" on the surface without cutting, the material will harden instantly. Rigid machines and constant, heavy feeds are mandatory.

• Cold Forming: This grade can be cold-formed to significantly increase its strength (reaching yield strengths over $800$ MPa), all while maintaining its non-magnetic properties.

• Welding: It is weldable using austenitic fillers, but care must be taken to manage the heat input to avoid nitrogen outgassing or the formation of unwanted phases in the heat-affected zone (HAZ).