XM-19 is a highly alloyed austenitic stainless steel, listed in ASTM A276/A479 as UNS S20910. It is also commonly known as Nitronic® 50, and in our range as Fermonic® 50.
Corrosion resistance
The combination of chromium (20.50-23.50%), increased molybdenum (1.5-3.0%) and raised nitrogen (0.20-0.40%) gives a pitting resistance equivalent number (PREN) above 34. That is comparable with a duplex stainless steel such as Sanmac® 2205 (1.4462), and well beyond standard 3xx grades, where the PREN is around 25. It therefore offers good corrosion resistance.
Applications
Typical uses include oil and gas down-hole equipment, marine pumps, valves, masts, tie-downs, fixtures and fittings, food processing equipment, and pulp and paper valves and fittings. Valve stems are perhaps the most common single application: as an austenitic stainless steel, XM-19 has better impact strength across a wider temperature range than alternative grades, which matters where a stem sees more of a shock loading when actuating a large valve.
Marine fixtures and fittings are the next most common use, thanks to the relative ease of fabrication without compromising corrosion resistance.
Is XM-19 the same as DIN 1.3964?
DIN 1.3964 is frequently referenced alongside XM-19, but the two cannot be considered identical. 1.3964 has an increased molybdenum content (3.0-3.5%) and an associated increase in nickel content (15.0-17.0%) to retain the desirable austenitic microstructure. These additions will improve corrosion performance, but also increase the cost markedly, so 1.3964 lies outside the XM-19 range.
Our two specifications
We offer XM-19 in two specifications: a standard solution-annealed version (Fermonic® 50 - Annealed) and a higher-strength version (Fermonic® 50 - HS). The higher strength comes from a combination of cold working or warm working (rolling at lower temperatures) to impart a degree of strain hardening.