X8CrMnN19-19 Cr-Mn-N Steel Round Bar

Product Description

X8CrMnN19-19, identified by the Werkstoff number 1.3819, represents the high-performance end of the Chromium-Manganese-Nitrogen austenitic steel family. Often referred to by trade names like Amagnit 3819, this grade is engineered for maximum stability of the austenitic phase, ensuring that the material remains strictly non-magnetic even under the most extreme mechanical or thermal stresses.

1. Chemical Composition

The "19-19" designation signifies a robust balance of Chromium and Manganese, which facilitates the absorption of a very high Nitrogen content.

2. Physical and Mechanical Properties

X8CrMnN19-19 is defined by its high energy absorption and its refusal to become magnetic.

• Absolute Non-Magnetism: It features a magnetic permeability ($\mu$) of $\leq 1.005$. This is significantly lower and more stable than standard 316L, which can become slightly magnetic when welded or cold-formed.

• Yield Strength ($R_{p0.2}$): $\geq 460$ MPa. This high baseline strength is achieved through solid-solution strengthening by Nitrogen.

• Tensile Strength ($R_m$): $850 – 1100$ MPa.

• Ductility: Despite its high strength, it maintains an elongation ($A_5$) of $\geq 30\%$, providing excellent resistance to brittle fracture.

3. Comparison with 1.3816 (X8CrMnN18-18)

While very similar to the "18-18" grade, 1.3819 (19-19) offers a slight boost in:

1. Pitting Resistance: The extra percentage of Chromium enhances its performance in chloride-rich environments.

2. Phase Stability: The 19-19 balance is specifically optimized to prevent the formation of "delta ferrite" during welding, ensuring the weld seam is just as non-magnetic as the base material.

4. Primary Applications for Round Bars

The round bar and rod forms of 1.3819 are essential in high-tech and defense sectors:

• Submarine and Naval Construction: Used for "magnetic silence" components, including specialized drive shafts, hull penetrations, and fasteners that must not trigger magnetic-sensing mines.

• Oil & Gas (Directional Drilling): Non-magnetic housings for Measurement While Drilling (MWD) and Logging While Drilling (LWD) tools. It allows sensors to accurately detect the Earth's magnetic north while surrounded by high-pressure drilling mud.

• Generator Retaining Rings: These bars are forged into rings that secure the rotor windings. They must withstand massive centrifugal forces while remaining magnetically inert to prevent induction heating losses.

• Fusion Energy & Physics: Structural supports for Tokamak reactors and particle accelerators where magnetic fields are measured in Teslas ($T$).

5. Technical Processing Notes

• Work Hardening: Like all Cr-Mn-N steels, 1.3819 hardens rapidly. If a drill bit or lathe tool dwells for even a second without removing material, the surface will become harder than the tool itself.

• Machining Strategy: Use rigid setups with high-torque spindles. Heavy feeds and slow surface speeds are required to "get under" the work-hardened layer created by the previous pass.

• Welding: Standard austenitic fillers can be used, but for critical non-magnetic applications, matching Cr-Mn-N fillers are required to maintain the $\mu \leq 1.005$ rating across the joint.

6. Summary of Standards

• Werkstoff-Nr: 1.3819

• DIN/EN: X8CrMnN19-19

• Industry Class: High-Nitrogen Austenitic (HNA) Steel