Introduction
Nitronic 50® stainless steel is an austenitic stainless steel with a blend of strength and corrosion resistance that is higher than stainless steel grades 316, 316/316L, 317, and 317/317L .
The high strength, corrosion resistance, and low magnetic permeability of this alloy allows it to be used as a material for medical implants.
The following sections will discuss in detail about stainless steel grade NITRONIC® 50 (XM-19).
Chemical Composition
The chemical composition of stainless steel grade NITRONIC® 50 (XM-19) is outlined in the following table.
| Element | Content (%) |
|---|---|
| Chromium, Cr | 20.5-23.5 |
| Nickel, Ni | 11.5-13.5 |
| Manganese, Mn | 4-6 |
| Molybdenum, Mo | 1.5-3 |
| Silicon, Si | 1 max |
| Nitrogen, N | 0.20-0.40 |
| Niobium, Nb | 0.10-0.30 |
| Vanadium, Va | 0.10-0.30 |
| Phosphorous, P | 0.04 max |
| Carbon, C | 0.06 max |
| Sulfur, S | 0.010 max |
Physical Properties
The physical properties of stainless steel grade NITRONIC® 50 (XM-19) are tabulated below.
| Properties | Metric | Imperial |
|---|---|---|
| Density | 7.88 g/cm3 | 0.285 lb/in3 |
Mechanical Properties
The following table shows mechanical properties of stainless steel grade NITRONIC® 50 (XM-19).
| Properties | Metric | Imperial |
|---|---|---|
| Tensile strength | 690 MPa | 100 ksi |
| Yield strength | 380 MPa | 55 ksi |
| Elongation | 35% | 35% |
| Hardness | 293 | 293 |
Other Designations
Other designations that are equivalent to stainless steel grade NITRONIC® 50 (XM-19) include the following:
- AMS 5764
- ASTM A240
- ASTM A276
- ASTM A312
- ASTM A314
- ASTM A403
- ASTM A479
- ASTM F1314
- NACE MR0175/ISO 15156-3
- NACE MR0103
Fabrication and Heat Treatment
Machinability
Stainless steel grade Nitronic® 50 has machinability characteristics that are similar to other austenitic stainless steels; however it requires slower speeds, more power, and higher rigidity due to its high work hardening rate. It is recommended that coated carbide tooling be used.
Forming
Stainless steel grade Nitronic® 50 can be formed using the same methods applied for other austenitic stainless steels. More power for forming and forging is needed for this alloy. Forging can be done at 1177-1204°C (2150-2200°F).
Welding
Welding of stainless steel grade Nitronic® 50 can be performed using traditional joining processes. Recommended filler metal should be Nitronic® 50W (AWS E/ER209).
Caution should be taken while using autogenous, high power density joining processes such as EB or laser welding, due to low FN potential and severe outgassing possibility.
Heat Treatment
Final annealing process performed for several of the applications, is done at 1065°C (1950°F), which is followed by water quenching. In case this material is used in a strongly corrosive environment, annealing should be done at 1121°C (2050°F). This alloy cannot be hardened by heat treatment.
Applications
NITRONIC® 50 (XM-19) is widely used in the following sectors:
- Textile
- Marine
- Nuclear
- Medical
- Fertilizer
- Chemical
- Petroleum
- Petrochemical
- Food processing
- Pulp and Paper
Some of the key products made using NITRONIC® 50 (XM-19) include:
- Tanks
- Valves
- Chains
- Cables
- Fittings
- Fasteners
- Pressure vessels
- Saltwater pumps
- Marine hardware
- Marine pump shafts
- Screens and wire cloths
- Photographic equipment
- Underwater robotic arms
- Positive displacement pumps
