ASTM A276 XM-19, also designated UNS S20910, is a nitrogen-strengthened austenitic stainless steel with significant molybdenum and manganese additions. In comparison with conventional grades such as 316 or 316L, XM-19 delivers roughly twice the ambient yield strength and superior resistance to localized corrosion, making it a cost-effective asset for food processing, marine, petrochemical and cryogenic service.
Key Takeaways
Ambient yield strength is nearly twice that of grade 316.
Outstanding corrosion resistance in marine, chemical and chloride-bearing media.
Mechanical properties remain outstanding at cryogenic temperatures.
Supply range: 3.17-350 mm diameter rod, forged, hot rolled, cold drawn or peeled.
Why XM-19 Outperforms Conventional Stainless
Unlike grade 304, which relies mainly on nickel and chromium, the XM-19 composition adds molybdenum and manganese in significant amounts, and nitrogen strengthening boosts both strength and pitting resistance. At ambient temperature the yield strength of XM-19 bar is almost twice that of grade 316, which allows smaller sections for the same design load and reduces component weight in marine and chemical equipment.
Corrosion and Environmental Performance
The mechanical properties and corrosion resistance of XM-19 are rated outstanding even at cryogenic temperatures, which extends its use to LNG and low-temperature chemical processes. The molybdenum-bearing composition resists pitting and crevice corrosion in seawater, and the alloy performs well in the chemical-laden environments of the pulp and paper and textile industries, where process streams range from elevated temperatures to cold service.
Specifications
XM-19 rod is supplied to ASTM A276 and A479, with related standards including GB/T 1220, JIS G4311/G4318 and EN 10088-3. Round bars range from 3.17 mm to 350 mm diameter, with square, flat, hexagon, angle and threaded forms available. Production techniques include forged, hot rolled, cold drawn and peeled, with bright, pickled or black surfaces. Standard lengths are 3000 mm or 6000 mm, or to customer requirement.
Applications
The utility of XM-19 extends beyond food processing and marine industries into petroleum, petrochemical and chemical plants, where process chemicals operate at elevated and cryogenic temperatures. Its combination of corrosion resistance, strength and economical cost makes it a valuable material for pump shafts, valve stems, fasteners and instrumentation components.
Frequently Asked Questions
Q: What is ASTM A276 XM-19?
A nitrogen-strengthened austenitic stainless steel, UNS S20910, with molybdenum and manganese additions for strength and corrosion resistance.
Q: How strong is XM-19 compared with 316?
At ambient temperature its yield strength is almost twice that of grade 316.
Q: Is XM-19 suitable for cryogenic service?
Yes, mechanical properties and corrosion resistance remain outstanding at cryogenic temperatures.
Q: What diameters are available?
Round bars from 3.17 mm to 350 mm, with square, flat, hexagon, angle and threaded forms.
Q: What standards cover XM-19 bar?
ASTM A276 and A479, with GB/T 1220, JIS G4311/G4318 and EN 10088-3 as related standards.
Q: Why is XM-19 more expensive than 304/316?
Higher alloy content and nitrogen strengthening raise cost, but the corrosion resistance and strength justify it in demanding service.
