Meets Your Performance Specs While Improving Total Cost of Ownership
When strength and corrosion-resistance are critical, duplex steel eliminates the tradeoff between 300 and 400 Series stainless. Duplex and super duplex stainless steel combine both properties into a single material—delivering corrosion resistance similar to 300 Series with up to 2X the strength—and Spuncast’s centrifugal casting ensures that performance is consistent, repeatable, and built for real-world applications.
The Real Challenge: Strength and Corrosion-Resistance Rarely Work Together
In many applications, engineers are forced into a compromise. 300 Series stainless steels provide corrosion resistance. 400 Series steels offer strength. But neither does both—and in many cases, materials that resist corrosion fail to maintain shape under load. That tradeoff creates real problems in the field:
- Components deforming or losing shape under pressure
- Premature corrosion in water, chloride, or chemical environments
- Overbuilt designs with unnecessary wall thickness and weight
- Increased maintenance cycles due to fatigue and wear
For a detailed comparison between 300 Series, 400 Series, and duplex stainless, see the FAQ section below.
Why Centrifugally Cast Duplex and Super Duplex Steel Is the Right Choice for Tubing
Centrifugally cast duplex tubing is the right choice for applications where both corrosion resistance and strength are critical—such as offshore and marine systems, oil and gas, water and wastewater treatment, chemical processing, and food processing. The key benefits include:
Higher Strength That Holds Shape Under Load
- Thinner wall designs
- Reduced material usage
- Improved dimensional stability
Corrosion Resistance Built for Harsh Environments
Duplex provides corrosion resistance similar to 300 Series stainless, while centrifugal casting ensures consistent performance in demanding environments.
- Performs in water, chloride, and chemical exposure
- Lower nickel content can stabilize material cost
- Reliable performance across production runs
Custom Tubing Designed to Your Specifications
Centrifugal casting produces near-net tubular shapes tailored to your exact application, eliminating the limitations of off-the-shelf material and giving you access to 200+ alloy options to match your exact performance requirements.
- Exact wall thickness and diameters
- Application-specific alloy selection
- Reduced machining and material waste
Forging-Level Performance Without the Cost and Lead Time
- Dense, high-integrity structure
- Consistent mechanical properties
- More efficient production for tubular components
Value-Added Capabilities for Centrifugally Cast Duplex
Material performance is only part of the equation. How duplex is engineered, processed, and delivered determines whether you achieve predictable results at the lowest total cost of ownership.
Metallurgical Expertise
- Controls melt chemistry and phase balance
- Verifies mechanical properties to specification
- Optimizes microstructure for strength and corrosion resistance
1,000+ Permanent Molds
- Broad OD coverage without new tooling investment
- Faster startup for repeat programs
- Improved consistency across long production runs
Metal Testing, Traceability, and Certification
- In-house chemical and mechanical testing
- Produced to applicable ASTM standards
- Unique heat number for full traceability
Precision Machining
Integrated machining ensures final tolerances align with casting and heat treatment, while high material yield from centrifugal casting (often 70–90% usable) further reduces scrap and improves machining efficiency.
- Turning, boring, and honing for tubular geometries
- Tight ID and OD tolerances
- Near-net hollow shape reduces machining waste vs. solid forms
Heat Treating
- Controls phase balance and mechanical properties
- Supports consistent through-wall performance
- Reduces risk of distortion and variability
Spuncast Shipping Services
- Freight consolidation to reduce overall shipping costs
- Coordinated logistics from melt through final delivery
- Protective packaging and handling to prevent damage in transit
The Big Question
How Does Centrifugal Casting Reduce Total Cost of Ownership for Duplex?
- Higher strength allows thinner walls and reduced material volume
- 70–90% usable material yield reduces scrap and improves machining efficiency
- 95%+ domestic sourcing reduces supply chain risk and improves cost stability
When properly engineered, the combined material and manufacturing advantages of centrifugally cast duplex typically outweigh the base alloy cost.
Learn more about our pricing, including our free shipping for first-time customers!
Duplex Stainless Steel Capabilities and Grades
Spuncast centrifugally casts duplex and super duplex grades that meet industry specifications, with performance engineered to match demanding service conditions.
Typical equivalents include:
- 2205 duplex stainless
- 2507 super duplex stainless
When properly controlled, centrifugally cast duplex can achieve mechanical and corrosion performance equivalent to wrought grades such as 2205 and 2507—ensuring confidence in both design and field performance.
Industry Standards
Spuncast centrifugal cast duplex grades equate to the following industry standards:
| Spuncast Alloys | 1A CD4MCu | 4A CD3MN | CD7MCuN | 1B CD4MCUN | DPX-1B MOD | 5A CE3MN |
|---|---|---|---|---|---|---|
| Similar Alloy | - | 2205 | Ferralium255® | - | - | 2507 |
| Industry Standards | ||||||
|---|---|---|---|---|---|---|
| ASTM Standard | A 890 A 995 | A 890 A 995 | - | A 890 A 995 | - | A 890 A 995 |
| UNS | J93370 | J92500 | S32550 | J93372 | - | J93404 |
| Similar DIN | - | 1.4462 | 1.4507 | - | - | 1.441 |
Chemical Composition
Spuncast centrifugal cast duplex grades are composed of the following chemical specifications:
| Spuncast Alloys | 1A CD4MCu | 4A CD3MN | CD7MCuN | 1B CD4MCUN | DPX-1B MOD | 5A CE3MN |
|---|---|---|---|---|---|---|
| Carbon max | 0.04 | 0.03 | 0.04 | 0.04 | 0.04 | 0.03 |
| Manganese max | 1 | 1.5 | 1.5 | 1 | 1.5 | 1.5 |
| Silicon max | 1 | 1 | 1 | 1 | 1.1 | 1 |
| Phosphorus max | 0.04 | 0.04 | 0.04 | 0.04 | 0.04 | 0.04 |
| Sulfur max | 0.04 | 0.02 | 0.03 | 0.04 | 0.04 | 0.04 |
| Chromium | 24.5-26.5 | 21.0-23.5 | 24.0-27.0 | 24.5-26.5 | 24.5-26.5 | 24.0-26.0 |
| Nickel | 4.75-6.00 | 4.5-6.5 | 4.5-6.5 | 4.7-6.0 | 4.5-6.0 | 6.0-8.0 |
| Molybdenum | 1.75-2.25 | 2.5-3.5 | 2.9-4.0 | 1.7-2.3 | 2.5-4.0 | 4.0-5.0 |
| Other | Cu2.75-3.25 | Cu1.00 max N.10-.30 | Cu 1.5-2.5 N .10-.25 | CU 2.7-3.3 N .10-.25 | Cu 1.3-3.0 N .18-.26 | N .10-.30 |
Mechanical Properties
Spuncast centrifugal cast duplex grades have the following mechanical properties:
| Spuncast Alloys | 1A CD4MCu | 4A CD3MN | CD7MCuN | 1B CD4MCUN | DPX-1B MOD | 5A CE3MN |
|---|---|---|---|---|---|---|
| Tensile (min) - KSI (MPa) | 100(690) | 90(620) | 105(725) | 100(690) | 110(758) | 100(690) |
| Yield (min) - KSI (MPa) | 70(485) | 60(415) | 70(485) | 70(485) | 70(485) | 75(515) |
| Elongation (2" min) | 16% | 25% | 20% | 16% | 20% | 18% |
| Brinell Hardness (10mm - 3000Kg -) Typical Values | 235 typical | 235 typical | 235 typical | 235 typical | 235 typical | 218 typical |
| Density lbs/in | 0.28 | 0.28 | 0.28 | 0.28 | 0.28 | 0.28 |
Industries and Applications
Common industries include:
•
Oil and gas
•
Offshore and marine
•
Water and wastewater treatment
•
Food processing
•
Chemical processing
Typical applications include:
•
Hydraulic cylinders
•
Pressure components
•
Offshore accumulators
•
Pump components
Who We Help
Design Engineers
Manufacturing Engineers
Procurement Teams
Operations Teams
Why Spuncast
With decades of experience in centrifugal casting and a deep understanding of duplex and super duplex stainless steels, Spuncast delivers more than material—we deliver a complete, repeatable solution for demanding tubular applications.
- 50+ years of centrifugal casting experience focused on high-performance alloys
- Proven performance in demanding industries where corrosion and structural failure are not an option
- In-house metallurgy, heat treatment, and machining for full process control
- 1,000+ permanent molds supporting repeatable production and faster lead times
- 95%+ domestic sourcing to reduce supply chain risk and variability
- Full material traceability and quality systems aligned with industry standards
This combination of experience, process control, and supply chain stability ensures that your duplex tubing performs as expected—not just once, but across every production run.
Learn more about our pricing, including our free shipping for first-time customers!
Frequently Asked Questions About Duplex Steel Tubing
Fundamentals
What is duplex stainless steel?
- The corrosion resistance of 300 Series stainless
- The strength of 400 Series stainless
What makes duplex different from other stainless steels?
- Corrosion resistance comparable to 300 Series stainless
- Significantly higher strength — often up to twice that of austenitic grades
Does duplex stainless steel rust?
Under the right conditions, it won’t rust. Like all steels, corrosion is still possible — but duplex is specifically designed to resist:
- Chloride pitting
- Crevice corrosion
- Stress corrosion cracking
It is significantly less susceptible to rust than standard stainless grades when properly applied.
Is duplex stainless steel magnetic?
- Some duplex grades may be slightly magnetic
- Others may not be
Comparisons & Grade Selection
How does duplex stainless steel compare to 300 and 400 Series stainless steels?
Duplex essentially combines the advantages of both:
- From 300 Series: corrosion resistance
- From 400 Series: strength
Compared to 300 Series:
- Much stronger
- Similar corrosion resistance
Compared to 400 Series:
- Much better corrosion resistance
- Slightly higher cost due to alloy content
When should I choose duplex over other stainless steels?
- You need corrosion resistance and strength
- Your current material isn’t holding its shape
- The environment includes water, chlorides, or chemicals
- Failure or downtime is costly
If a 300 Series grade works chemically but lacks strength, duplex is often the right upgrade.
What’s the difference between duplex and super duplex stainless steel?
Super duplex is an enhanced version of duplex with higher alloy content. This typically results in:
- Increased corrosion resistance
- Higher strength
- Better performance in aggressive environments like offshore oil and gas
How does duplex compare to super austenitic stainless steels?
- Strong corrosion resistance
- Much higher strength
Is cast duplex equivalent to wrought grades like 2205 and 2507?
- Wrought = rolled or drawn
- Cast = poured and solidified
How do I determine which duplex grade is right for my application?
- Strength requirements
- Corrosion resistance needs
- Budget
Performance & Operating Limits
What types of environments is duplex stainless steel best suited for?
- Water and wastewater treatment
- Food processing (clean, corrosion-resistant, durable)
- Offshore and marine environments
- Oil and gas and chemical processing
What are the temperature limits of duplex stainless steel?
- It performs well across a wide temperature range
- Performance only begins to decline at very high temperatures
What causes duplex stainless steel to fail in service?
The most common failure mode is fatigue over time. In applications with repeated stress or cycling:
- Small cracks can form
- Over time, those cracks grow
- Eventually, the material fails
In static applications, duplex can last for decades — even generations — without replacement.
Manufacturing & Casting
Can duplex stainless steel be centrifugally cast?
Yes — and it’s one of the most effective ways to produce duplex tubing. Centrifugal casting is ideal for tubular components and allows for consistent material properties and controlled production.
What are the advantages of centrifugal casting for duplex components?
Centrifugal casting offers several advantages:
- Mechanical properties similar to forged material
- Custom sizes and wall thicknesses
- Reduced material waste
- Ability to produce a wide range of duplex grades
- Unlike warehouse stock, parts are made to your exact specifications.
How do you ensure proper phase balance and chemistry control when casting duplex?
Phase balance is controlled through alloy chemistry during melting. By adjusting the composition, manufacturers control:
- Ferrite content
- Strength
- Corrosion resistance
Proper control at this stage ensures consistent, reliable performance in the final product.
Cost & Sourcing Considerations
Is duplex stainless steel more expensive than other stainless steels — and when does it reduce total cost of ownership?
- More expensive than 400 Series stainless (low alloy)
- Comparable to many 300 Series grades
- Sometimes lower cost due to reduced nickel content
- Higher strength allows thinner sections
- Longer lifespan reduces replacement costs
- Improved reliability reduces downtime