What material is ASTM A479 xm-19?
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What is ASTM A479 XM-19?
ASTM A479 XM-19, also known as Nitronic 50 or UNS S20910, is a high-strength austenitic stainless steel with excellent corrosion resistance. It is supplied under ASTM A479 when used in pressure vessel and pressure piping applications.
Material Overview:
UNS Designation: S20910
Standard: ASTM A479 (for pressure-containing parts like pressure vessels and piping)
Common Trade Names: Nitronic 50®, XM-19
Type: Austenitic stainless steel (non-magnetic in annealed condition)
ASTM A479 XM-19 Chemical Composition (Typical):
| Element | Content (%) |
|---|---|
| Chromium (Cr) | 20.5–23.5 |
| Nickel (Ni) | 11.5–13.5 |
| Manganese (Mn) | 4.0–6.0 |
| Molybdenum (Mo) | 1.5–3.0 |
| Nitrogen (N) | 0.20–0.40 |
| Carbon (C) | ≤ 0.06 |
| Iron (Fe) | Balance |
Mechanical Properties of XM-19 (Typical Values)
| Property | Annealed Condition | Cold Worked Condition |
|---|---|---|
| Tensile Strength (MPa / ksi) | 690 MPa / 100 ksi | Up to 1035 MPa / 150 ksi |
| Yield Strength (0.2% offset) | 379 MPa / 55 ksi | Up to 724 MPa / 105 ksi |
| Elongation | ≥ 35% | ≥ 20% |
| Hardness (Rockwell B) | ≤ 95 HRB | Up to 35 HRC (cold-worked) |
| Modulus of Elasticity | ~193 GPa | - |
What standards cover XM-19 material?
ASTM A479 – for pressure vessel bars and forgings
ASTM A276 – for general-purpose stainless steel bars
UNS S20910 – unified number system designation
ASME SA479 – pressure equipment use in ASME code systems
Is XM-19 stronger than 316 or 304 stainless steel?
Yes. XM-19 provides approximately double the yield strength of 304 or 316 in the annealed condition, and even higher when cold worked.
Is XM-19 magnetic?
No. XM-19 is non-magnetic, even after cold working-unlike many other high-strength stainless steels.
Can XM-19 be welded?
Yes. XM-19 has good weldability using standard austenitic stainless welding procedures. However, low heat input and post-weld cleaning are recommended to maintain corrosion resistance.
How does XM-19 perform in seawater?
XM-19 has superior pitting and crevice corrosion resistance compared to 316L, making it well-suited for marine and saltwater environments.
