x40MnCrN19/K Cr-Mn-N Steel Round Bar

Product Description

X40MnCrN19 is a high-nitrogen, high-manganese austenitic stainless steel primarily recognized by the Werkstoff number 1.3815. It is often referred to in the industry as P530. This grade is specialized for applications requiring an exceptional combination of yield strength,corrosion resistance, and absolute non-magnetism.

The "/K" suffix usually denotes that the material has been cold-worked (Kaltverformt) to reach specific high-strength mechanical properties, as this alloy does not respond to conventional heat treatment for hardening.

1. Chemical Composition

The "40" in the designation represents a carbon content of approximately $0.40\%$, which is higher than many other Cr-Mn-N grades, contributing to its high strength.

2. Physical and Mechanical Properties

X40MnCrN19/K is engineered to be a "high-strength non-magnetic" workhorse.

• Magnetic Permeability:$\mu \leq 1.005$. It remains strictly non-magnetic even after heavy cold working or impact.

• Yield Strength ($R_{p0.2}$): In the cold-worked condition (/K), yield strengths often exceed 700 – 900 MPa (roughly 4 times higher than standard 316L).

• Tensile Strength ($R_m$): Typically ranges from 900 to 1150 MPa.

• Corrosion Resistance: It offers excellent resistance to Stress Corrosion Cracking (SCC), which is a common failure mode for standard stainless steels in high-pressure, chloride-rich environments.

3. Key Applications

Because of its high fatigue strength and magnetic neutrality, X40MnCrN19 round bars are critical in:

• Oil & Gas (Downhole Drilling): Non-magnetic drill collars and stabilizer bodies. The high strength allows these tools to withstand the massive torque of deep-well drilling, while the non-magnetism allows directional sensors to function.

• Power Generation: Heavy-duty retaining rings for generator rotors.

• Defense & Marine: High-strength, non-magnetic fasteners and structural pins for naval vessels.

• Specialized Machinery: Shafts and bolts in medical or scientific equipment (like particle accelerators) where high mechanical loads and zero magnetic interference coexist.

4. Technical Comparison: X40MnCrN19 vs. X8CrMnN18-18

While both are "18-18" type steels (18% Cr, 18% Mn), the X40 version has significantly higher Carbon content.

1. Strength: X40MnCrN19 generally reaches higher hardness and yield levels than the X8 version.

2. Toughness: The X8 version (lower carbon) typically offers slightly better impact toughness at extremely low temperatures compared to the X40 version.

5. Machining and Processing Notes

• Work Hardening: This material has an extremely high work-hardening rate. It is imperative that the tool is always cutting; any "rubbing" or "dwelling" will create a localized hard spot that can destroy carbide inserts.

• Coolant: Use high-pressure, high-quality sulfur-free cutting oils or synthetic coolants to manage the heat generated during the machining of these high-strength bars.

• Welding: Welding X40MnCrN19 is complex due to the high Carbon and Nitrogen content. It is generally recommended to avoid welding if the high-strength properties of the "/K" condition must be maintained, as the heat will anneal the material and reduce its strength.

6. Industry Standards

• Werkstoff-Nr: 1.3815

• Trade Name: P530 / Amagnit 3815

• Standard: Typically manufactured according to specialized internal mill specs or EN 10088-3 (for general stainless properties).