Super Duplex Stainless Steel Seamless Pipe Overview
Super duplex stainless steel seamless pipes combine a ferritic-austenitic microstructure with high chromium, molybdenum and nitrogen alloying. They are selected for high strength and resistance to pitting, crevice corrosion and chloride-induced stress-corrosion cracking in offshore, marine, desalination and chemical process systems.
| Product range | UNS S32550, S32750, S32760 and S32950 seamless pipes |
|---|---|
| Primary standards | ASTM A790 / ASME SA790; project specifications subject to technical review |
| Manufacturing | Hot piercing or extrusion, cold drawing/pilgering where required, solution annealing, straightening and finishing |
| Typical service | Offshore oil and gas, seawater, desalination, chemical processing, marine and industrial chloride systems |
| Quotation basis | Grade, standard, OD, wall thickness, length or schedule, quantity, testing and delivery requirements |
Super Duplex Pipe Grade Selection
| UNS grade | Alternative designation | Key alloy distinction | Typical selection focus |
|---|---|---|---|
| S32550 | Ferralium 255 / Alloy 255 | Copper-bearing super duplex grade | Acidic chemical and seawater duties |
| S32750 | F53 / Alloy 2507 / EN 1.4410 | High Cr-Mo-N alloying; widely specified grade | Offshore, desalination and chloride service |
| S32760 | F55 / EN 1.4501 | Tungsten- and copper-alloyed grade | Severe offshore, subsea and erosive service |
| S32950 | UNS S32950 | Higher chromium with a leaner molybdenum range | Selected marine and industrial chloride systems |
Standards and Purchase Specification
| Requirement | Information to specify | Why it matters |
|---|---|---|
| Material | UNS grade and governing standard edition | Defines chemistry, mechanical properties and heat-treatment requirements |
| Dimensions | OD × wall thickness × length or NPS × schedule | Controls manufacturing route and dimensional tolerance |
| Service conditions | Temperature, pressure, fluid chemistry and chloride level | Supports technical material review |
| Inspection | MTC, NDT, PMI, corrosion testing or third-party inspection | Defines verification and documentation scope |
| Delivery | Surface, ends, packing, destination and required date | Supports an accurate quotation and delivery plan |
Manufacturing and Quality Documentation
| Stage | Typical control |
|---|---|
| Forming | Hot piercing or extrusion followed by sizing and optional cold working |
| Heat treatment | Solution annealing and rapid cooling according to grade and applicable specification |
| Dimensional inspection | OD, wall thickness, length, straightness, ends and surface condition |
| Integrity testing | Hydrostatic or nondestructive electric test; UT or eddy-current testing when specified |
| Documentation | Material Test Certificate and ordered chemical, mechanical, dimensional and inspection records |
Typical Applications
| Industry | Typical equipment | Engineering consideration |
|---|---|---|
| Offshore oil and gas | Flowlines, risers, manifolds and process piping | High strength, pressure integrity and chloride resistance |
| Desalination | RO piping, seawater intake and brine systems | Resistance to localized corrosion in saline media |
| Chemical processing | Process piping, reactors and heat-transfer systems | Grade selection based on acid chemistry and operating temperature |
| Marine and industrial water | Cooling water, fire mains and high-pressure water systems | Durability in chloride-bearing environments |
Super Duplex Seamless Pipe FAQ
What is a super duplex stainless steel seamless pipe?
It is a pressure-bearing pipe made without a longitudinal weld from a ferritic-austenitic stainless steel grade engineered for high strength and strong resistance to localized corrosion.
Which grades are available in this range?
This series includes UNS S32550, S32750, S32760 and S32950. Selection depends on fluid chemistry, temperature, pressure, required standard and project specifications.
Which standard is commonly used?
ASTM A790 / ASME SA790 is commonly specified. The exact edition, dimensions, heat treatment, tests and supplementary requirements should be stated in the purchase order.
What should I send for a quotation?
Send the UNS grade, standard, OD, wall thickness, length, quantity, delivery condition, inspection requirements and destination. Final availability and compliance are subject to formal technical review.