Comparison Guide
Super Duplex 2507 vs Inconel — Which for Chloride and Sour Service
For chloride-heavy service (subsea, produced water, chloride wellhead), the choice is often between Super Duplex 2507 and Inconel. Both work; the tradeoffs are cost, machinability, and temperature range. This guide covers when to choose which.
Property comparison
| Property | Super Duplex 2507 | Inconel 625 | Inconel 718 (aged) |
|---|---|---|---|
| Yield strength | ~80 ksi | ~60 ksi | ~150 ksi |
| Max service temperature | ~600°F (315°C) | ~1800°F (980°C) | ~1300°F (700°C) |
| Chloride SCC resistance | Excellent | Excellent | Good |
| H2S sour service | Good | Excellent | Good |
| Cost (relative) | 1 | 2–3 | 2–3 |
| Machinability | Moderate (temperature discipline) | Moderate | Difficult (especially aged) |
| Weldability | Good (qualified procedures) | Excellent | Moderate |
When to choose 2507
Chloride service at moderate temperatures (below ~500°F): 2507's corrosion resistance matches Inconel at half the cost. Standard choice for subsea bodies, chloride-heavy produced water handling, marine hardware.
Weld fabrications with qualified 2507 procedures. Structural components where 80 ksi yield is adequate.
When to choose Inconel 625
High-temperature applications above ~500°F: 2507 loses properties; 625 handles up to 1800°F. Standard for high-temperature valves, hot-service piping, exhaust components.
Severe H2S sour service: Inconel 625 has slightly better sour-service resistance than 2507 in the worst environments.
When to choose Inconel 718
High-strength requirements: 718 aged is ~2x stronger than 2507. Downhole tool bodies under high torque, high-pressure structural components. 625 doesn't have the strength.
When cost isn't the primary driver and strength+corrosion combination is needed.
Frequently asked questions
Is Super Duplex 2507 as corrosion-resistant as Inconel 625?
For chloride SCC and pitting, essentially yes — both are excellent. 625 has the edge in extreme high-temperature service. 2507 is roughly half the cost.
Why not always spec Inconel?
Cost. Inconel is 2–3x the price of 2507 per pound. For chloride service at moderate temperatures, 2507 delivers the same corrosion performance at lower cost.
Is 2507 harder to machine than Inconel?
About the same as Inconel 625 — moderate difficulty with temperature discipline. Both easier than aged Inconel 718.
Which is easier to weld?
Inconel 625 is the easiest of the three. 2507 requires qualified procedures. 718 aged requires post-weld heat treatment.