S32750 vs S32760: A Comprehensive Comparison of Super Duplex Stainless Steels

2026-04-24

Super duplex stainless steels are essential in harsh industrial environments for their high strength and corrosion resistance. S32750 and S32760, two widely used SDSS grades, share similar foundational properties but differ in alloy design, making them suitable for distinct scenarios.

1. Foundational Similarities

Both S32750 and S32760 have a dual-phase (austenite-ferrite) structure, PREn values exceeding 40, and high mechanical strength (yield strength ≥ 550 MPa), ensuring excellent resistance to chloride stress corrosion cracking. They also have comparable density, thermal conductivity, and processability with proper heat treatment.

2. Core Differences: Alloy Design & Performance

The key distinction lies in alloy composition: S32760 is an optimized version of S32750, enhanced with tungsten (W) and copper (Cu) for better performance in severe corrosive environments.

2.1 Chemical Composition

Both share core elements (Cr: 24.0-26.0%, Ni: 6.0-8.0%, Mo: 3.0-4.0%), but differ in three key aspects: S32760 contains 0.50-1.00% W and 0.50-1.00% Cu (absent in S32750), while S32750 has slightly higher nitrogen (0.24-0.32% vs. 0.20-0.30% for S32760). This makes S32760’s PREn ≥ 42 (vs. S32750’s ≥ 40) with better ductility, while S32750 has marginally higher tensile strength.

2.2 Heat Treatment

S32750 requires solution annealing at 1100°C, while S32760 needs 1080°C. Both require strict ferrite content control (35-60%) to avoid harmful secondary phases.

3. Typical Applications

S32750 suits moderate corrosion scenarios, while S32760 is for severe conditions.

3.1 S32750 (SAF 2507)

A cost-effective choice for: marine engineering (seawater pipes, ≤2000ppm chloride), petrochemicals (sulfur-containing crude pipes, non-strong acid desulfurization towers), water treatment (sewage/sweet water pretreatment pipes), and general industry (heat exchangers, storage tank connections, ≤250°C).

3.2 S32760 (Zeron 100/F55)

Ideal for severe corrosion: chemical industry (acid solution pipes, phenol units), high-end petroleum (deep-sea risers, 2000-3000ppm chloride), environmental protection (FGD absorption towers), and special industries (pharmaceutical chloride pipes, lithium battery fluoride pipes, ≤280°C).

4. Selection Guidelines

Corrosion Environment: S32760 for high chloride (>2000ppm) or strong acid; S32750 for moderate chloride (≤2000ppm) and non-acid media.
Mechanical Needs: S32760 for better ductility/toughness; S32750 for higher tensile strength in static loads.
Cost: S32750 is more budget-friendly; S32760 is pricier due to W/Cu and stricter certification.
Standards: High-end projects (deep-sea oil, FGD) often specify S32760—substitution risks safety issues.