Material Selection Guide

Choose the right nickel alloy for your operating conditions. Compare high temperature, acid corrosion, and fatigue resistance across different grades.

🔥 High Temperature
💧 Strong Acid
⚙️ Fatigue Resistance

600-800C Service

Intermediate temperature, oxidation resistance

Inconel 601
N06601 | ASTM B168
★★★★★
Inconel 625
N06625 | ASTM B443
★★★★
Alloy 800HT
N08811 | ASTM B409
★★★★
310S Stainless
S31008 | ASTM A240
★★★★★

800-1000C Service

High temperature, creep resistance critical

Inconel 601
Oxidation champion
★★★★★
Haynes 230
N06230 | Creep resistance
★★★★★
Inconel 625
Good balance
★★★★
Alloy 602CA
N06025 | Extreme temp
★★★★★

1000-1200C Service

Extreme temperature applications

Alloy 602CA
Up to 1200C intermittent
★★★★★
Haynes 230
Excellent up to 1150C
★★★★
Inconel 601
Good to 1100C
★★★★
RA330
N08330 | Carburization
★★★★★

Cyclic Temperature

Thermal cycling, thermal fatigue

Inconel 601
Best thermal fatigue
★★★★★
Alloy 800HT
Good cyclic resistance
★★★★
Haynes 230
Low expansion
★★★★

Hydrochloric Acid (HCl)

All concentrations, ambient to 80C

Hastelloy C276
N10276 | Up to 50% HCl
★★★★★
Hastelloy C22
N06022 | Oxidizing HCl
★★★★★
Zirconium 702
R60702 | Hot conc. HCl
★★★★★
Tantalum
All concentrations
★★★★★

Sulfuric Acid (H2SO4)

All concentrations, up to boiling

Hastelloy C276
Dilute to 60% H2SO4
★★★★★
Alloy 20
N08020 | < 60% H2SO4
★★★★★
Inconel 686
N06686 | All concentrations
★★★★★
254 SMO
S31254 | Dilute H2SO4
★★★★

Nitric Acid (HNO3)

Oxidizing acid environment

Alloy 825
N08825 | All concentrations
★★★★★
Inconel 690
N06690 | Conc. HNO3
★★★★★
304L Stainless
S30403 | Good resistance
★★★★

Mixed Acids

HNO3 + H2SO4, HCl + H2SO4

Hastelloy C22
Superior mixed acid
★★★★★
Hastelloy C276
Good versatility
★★★★
Inconel 686
Excellent resistance
★★★★★

High-Cycle Fatigue

> 10^5 cycles, elastic stress range

Inconel 718
N07718 | 1000+ MPa strength
★★★★★
Inconel 625
N06625 | Good fatigue life
★★★★
Monel K500
N05500 | Age hardenable
★★★★

Low-Cycle Fatigue

< 10^5 cycles, plastic strain

Inconel 718
Best LCF resistance
★★★★★
Waspaloy
N07001 | Turbine blades
★★★★★
Inconel 625
Good ductility
★★★★

Thermal Fatigue

Temperature cycling damage

Inconel 601
Best thermal cycling
★★★★★
Haynes 230
Low CTE
★★★★★
Alloy 800HT
Good resistance
★★★★

Corrosion Fatigue

Cyclic stress + corrosive environment

Monel 400
Seawater fatigue
★★★★★
Inconel 625
Good combination
★★★★★
Duplex 2205
High strength + corrosion
★★★★

Material Comparison Matrix

Material High Temp HCl H2SO4 Fatigue Cost
Inconel 625 Good Fair Fair Excellent $$$$$
Inconel 601 Excellent Fair Fair Excellent $$$$
Inconel 718 Good Fair Fair Excellent $$$$
Hastelloy C276 Good Excellent Excellent Good $$$$$$
Hastelloy C22 Good Excellent Excellent Good $$$$$$$
Monel 400 Fair Good Fair Excellent $$$
Alloy 800HT Excellent Fair Fair Good $$$
Duplex 2205 Fair Good Good Good $$

Quick Selection Guide

🔥 High Temperature Applications

  • Reformer tubes: Inconel 601
  • Heat treating baskets: Alloy 601
  • Combustion chambers: Haynes 230
  • Furnace components: RA330, 601
  • Thermal cycling: Inconel 601

💧 Acid Corrosion Applications

  • HCl reactors: C276, Zirconium
  • H2SO4 heat exchangers: C276
  • FGD scrubbers: C276, C22
  • Pickling lines: Alloy 20
  • Mixed acid: C22, C686

⚙️ Fatigue Resistance Applications

  • Turbine blades: Inconel 718
  • Pump shafts: Monel 400, K500
  • Spring materials: Alloy X750
  • Fasteners: Inconel 718
  • Seawater cycling: Monel 400

Need Help Selecting the Right Material?

Send your operating conditions: temperature, acid type/concentration, stress level, cycle frequency

Email: linyuquan@findsteel.cn

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