Super Alloy Nitronic 50 (UNS S20910)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Forging
     Annealing
     Hardening
Other Designations
Applications

Introduction

Nitronic 50 alloy is an austenitic, nitrogen strengthened steel that has corrosion resistance superior to grade 316 and 317 stainless steels. It has very good mechanical properties at both sub-zero and elevated temperatures. The alloy is capable of retaining low magnetic permeability even after exposure to sub-zero temperatures or severe cold working conditions.

In addition, the alloy has excellent resistance to sulfide stress cracking and intergranular attack. It can be readily fabricated, and it is considerably stronger than the conventional 300 series stainless steels.

The following datasheet will provide an overview of nitronic 50 alloy.

Chemical Composition

The chemical composition of nitronic 50 alloy 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
Nitrogen, N 0.2-0.4
Niobium, Nb 0.1-0.3
Vanadium, V 0.1-0.3
Carbon, C 0.06
Sulfur, S 0.03
Iron, Fe Balance

Physical Properties

The following table shows the physical properties of nitronic 50 alloy.

Properties Metric Imperial
Density 7.89 g/cm3 0.285 lb/in3

Mechanical Properties

The mechanical properties of nitronic 50 alloy are displayed in the following table.

Properties Metric Imperial
Tensile strength at break ≥ 689 MPa ≥ 100000 psi
Yield strength ≥ 379 MPa ≥ 55000 psi
Elongation at break ≥ 35% ≥ 35%

Thermal Properties

The thermal properties of nitronic 50 alloy are given in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (@25.6-93.3°C/78-200°F) 16.2 µm/m°C 9 µin/in°F

Fabrication and Heat Treatment

Machinability

Machining nitronic 32 alloy requires slow speeds, positive feeds and abundant resulfurized lubricant.

Forming

Nitronic 32 alloy can be formed using all common forming techniques.

Welding

Nitronic 32 alloy can be welded using all welding techniques such as gas tungsten arc, gas metal arc and submerged arc welding. Pre-heating is not required for this alloy.

Forging

Nitronic 32 alloy is forged at 1093°C (2000°F) and then heated to 1177°C (2150°F).

Annealing

Nitronic 32 alloy is annealed at 1038 to 1121°C (1900 to 2050°F) and quenched in water or air.

Hardening

The alloy can be hardened through cold working.

Other Designations

Other designations that are equivalent to nitronic 50 alloy include the following:

ASTM A182 (XM-19) ASTM A269 (XM-19) ASTM A412 (XM-19)
ASTM A193 (B8R, B8RA) ASTM A276 ASTM A479 (XM-19)
ASTM A194 (B8R, B8RA) ASTM A312 (XM-19) ASTM A580 (XM-19)
ASTM A240 (XM-19) ASTM A336 (XM-19) ASTM A813 (TP XM-19)
ASTM A249 (XM-19) ASTM A403 (XM-19) DIN 1.3964

Applications

The following are the list of applications of nitronic 50 alloy:

  • Fasteners
  • Marine hardware
  • Boat shafting
  • Pumps and valves

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