Key Feature

The Premium High-Temperature Nickel-Chromium-Iron Alloy Bar Stock. Exceptional oxidation and carburization resistance up to 1200°C, with superior strength and thermal fatigue resistance in cyclic heating applications.

The workhorse alloy for demanding high-temperature furnace and heat treatment bar applications.

Common Designations

UNS N08330
AISI/SAE 330
ASTM B572 (Nickel-Chromium-Iron Alloy Bars)
EN 1.4886, X15CrNiSi25-21
Werkstoff Nr. 1.4886
Alloy 330

Often categorized as a nickel-iron-chromium alloy rather than a stainless steel due to high nickel content.

Chemical Composition (Typical wt.%)

C: ≤ 0.08
Cr: 17.0 - 20.0Ni: 34.0 - 37.0Si: 0.75 - 1.50
Mn: ≤ 2.00
P: ≤ 0.040
S: ≤ 0.030

High nickel content (34-37%) distinguishes it from standard stainless steels and provides exceptional high-temperature stability.

Mechanical Properties

Tensile Strength: ≥ 550 MPa
Yield Strength: ≥ 240 MPa
Elongation: ≥ 30%
Hardness: ≤ 201 HB
Machinability: 30% of B1112 steel

Good room-temperature properties but designed specifically for elevated temperature performance.

Elevated Temperature Properties

Continuous Service: Up to 1200°C
Intermittent Service: Up to 1150°C
Oxidation Resistance: Excellent up to 1150°C
Carburization Resistance: Excellent
Creep Strength: Good up to 1100°C

Superior to 310S and other stainless steels in high-temperature cyclic applications.

Physical Properties

Density: 8.00 g/cm³
Melting Range: 1370 - 1430 °C
Thermal Expansion: 14.4 × 10⁻⁶/K (20-100°C)
Thermal Conductivity: 12.5 W/m·K (100°C)
Non-magnetic

Lower thermal expansion than standard austenitic stainless steels; beneficial for thermal cycling.

Available Forms

Rounds: 6mm - 200mm diameter
Squares: 6mm - 100mm
Hexagons: 6mm - 75mm
Flats: Various sizes
Billets: For forging applications
Forgings: Custom forged components

Available in sizes suitable for high-temperature component manufacturing.

Surface Conditions

Hot Rolled: Black bar
Cold Drawn: Bright finish
Centerless Ground: Precision ground
Polished: For specific applications
Peeled: Improved surface for machining

High-quality finishes available for precision applications.

Corrosion Resistance

Excellent oxidation and carburization resistance at high temperatures. Good resistance to sulfur-bearing atmospheres, nitriding environments, and thermal shock.

Specifically designed for high-temperature corrosion resistance rather than room-temperature chemical resistance.

Machining Characteristics

• Difficult to machine due to work hardening
• High tool wear• Requires rigid setups• Good chip control with proper techniques
• Surface finish achievable with care

More challenging to machine than standard stainless steels; requires expertise.

Welding Characteristics

Good weldability with proper techniques
Solution annealing after welding recommended
Matching filler metals essential
Heat input control important

Requires similar precautions to other high-temperature alloys.

High-Temperature Strength Retention

At 800°C: ~35% of room temp strength
At 900°C: ~25% of room temp strength
At 1000°C: ~15% of room temp strength

Significant strength retention at high temperatures compared to stainless steels.

Key Standards

ASTM B572 330: Nickel-Chromium-Iron Alloy Bars
AMS 5593 (Aerospace)
EN 10095: Heat-resisting steels
ASME SB572: Code Construction

Specified in both heat-resisting and nickel alloy standards.

Common Applications

• Furnace Components: Radiant tubes, retorts, muffles, furnace rails, hangers
• Heat Treatment Fixtures: Baskets, trays, fixtures, hangers, support rods
• Thermal Processing: Kiln furniture, pyrolysis components, calciner parts
• Petrochemical: Reformer tubes, pyrolysis coils, cracking furnace components
• Power Generation: Boiler components, superheater supports, high-temperature fasteners
• Aerospace: Afterburner components, exhaust system parts
• Glass Manufacturing: Lehr components, mold handling equipment, glass tank parts

Specifically designed for continuous high-temperature operation in demanding environments.