Our DIN933 S32750 Super Duplex Bolts are built to ASTM A193 standards, using S32750 super duplex material with a strong chemical mix: 24-26% chromium, 6-8% nickel, 3-4% molybdenum, and 0.18-0.22% nitrogen. This combo gives them a tensile strength of 800-1000 MPa-way stronger than regular duplex bolts-and makes them hold up incredibly well against rust in tough spots like saltwater or chemical tanks.
We put them through a 6% ferric chloride test (following ASTM G48 Method C) at 50°C, and they didn't show any pitting even after 300 hours. That's why they're a go-to for offshore rigs, desalination plants, or any place where both strength and resistance to corrosion are musts. For wholesalers, this means you can stock one type of bolt that handles a bunch of tough jobs, so you don't have to keep as many different kinds on hand.
We offer two finishes: pickled (per ASTM A380) to boost corrosion resistance by creating a 7-9μm protective layer, and oiled (with a light mineral coating) to keep threads in good shape during storage. The pickled finish makes them 40% more resistant to pitting than untreated bolts in chloride tests.
Our threading is spot-on: UNC threads (ASME B1.1) have a tolerance of ±0.015mm, so they fit nuts perfectly. We can also make custom lengths (10mm to 300mm) with ±0.3mm tolerance, using cold heading machines that don't weaken the metal. Every bolt gets a hardness check (Rockwell C 28-35, per ASTM E18) before shipping to make sure they're consistent.
As a Chinese manufacturer with 10 years supplying EU and US offshore industries, we run 7 dedicated production lines-including 3 high-precision CNC machines-with an annual capacity of 3,200 tons. Our raw material goes through vacuum degassing to keep impurities low, with oxygen content under 15ppm, checked by our in-house OES machine (accurate to 0.001%).
We keep 500-600 tons in stock at our Ningbo warehouse, covering sizes from ¼" to 2½" in diameter and lengths from 1" to 12". Inventory updates twice a day on our website, and FOB Ningbo shipments for in-stock bolts leave within 6 days-helping you keep your customers' projects on track.
We are a reputable wholesale manufacturer and solemnly promise to provide the following guarantees for your DIN933 S32750 Super Duplex Bolts order:
First, Quality Guarantee: Any bolts that do not meet the DIN933 S32750 Super Duplex Bolts standard will be replaced free of charge, at no cost to you.
Second, Fast Delivery: We maintain a year-round inventory of commonly used sizes (M8-M30) of DIN933 S32750 Super Duplex Bolts.
Third, Production Transparency: We can provide production capacity reports and factory audit videos upon request, allowing you to showcase our manufacturing capabilities to your clients.
Fourth, 24/7 Support: We will assign a dedicated account manager to provide you with professional support for your DIN933 S32750 Super Duplex Bolts order. Please feel free to contact us if you need assistance with technical specifications, order updates, or any other matters.
Super Duplex Stainless Steel S32750 (UNS S32750; also known as 2507, DIN 1.4410)
Chemical Composition
Cr: 24.0-26.0%, Ni: 6.0-8.0%, Mo: 3.0-4.0%, N: 0.18-0.22%, C: ≤0.03%, Mn: ≤1.0%, Si: ≤0.8%, P: ≤0.03%, S: ≤0.02%, Cu: ≤0.5%
Mechanical Properties
Tensile Strength: ≥800 MPa
Yield Strength: ≥550 MPa
Hardness: ≤310 HB (Brinell); ≤32 HRC
Elongation: ≥15%
Corrosion Resistance
Excellent resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC) in high-chloride environments (e.g., seawater, acidic brines). Pitting Resistance Equivalent (PREN) ≥40, outperforming standard duplex (2205) and austenitic steels (316).
Temperature Range
Service temperature: -50°C to 300°C (ideal for high-pressure, harsh industrial and offshore settings).
Magnetic Property
Magnetic (duplex microstructure: ~50% ferrite + ~50% austenite)
Hexagonal (hex) head (6-sided, standard for wrench tightening)
Thread Type
Partial thread (threaded from the end up to a specified length, leaving a smooth shank under the head) or full thread (optional, based on application)
Thread Standards
Metric Coarse (ISO), UNC (Unified National Coarse), UNF (Unified National Fine)
Metric Sizes (M)
M6 to M64 (common: M8, M10, M12, M16, M20, M24, M30)
Imperial Sizes
1/4" to 2-1/2" (common: 3/8", 1/2", 5/8", 3/4", 1")
Length Range
20 mm to 1000 mm (metric); 1" to 40" (imperial)
Standards Compliance
ASTM A193 B8S, ASME SA193, ISO 898-1, DIN 931 (partial thread), DIN 933 (full thread)
Key Applications
Offshore oil and gas: wellheads, subsea pipelines, valve assemblies
Chemical processing: high-pressure reactors, chloride-based fluid systems
Desalination plants: brine handling equipment
Marine engineering: shipboard systems, offshore platforms
Surface Finish
Pickled, passivated, or polished (to maximize corrosion resistance and minimize contamination)
Frequently Asked Questions
Q: What materials do your products mainly include?
A: Our products mainly include carbon steel, stainless steel, and alloy steel, with a focus on pipes, flanges, and fittings.
Q: How long does it take to produce a custom order with special specifications?
A: It usually takes 25-30 days, depending on the complexity of the design. We'll confirm the exact lead time after evaluating your requirements.
Q: Can you provide a detailed product catalog?
A: Sure, we'll send you a digital catalog with specifications, prices, and photos via email. Just let us know your specific needs.
Contact now
