Seamless Super Duplex Stainless Steel Pipes to ASTM A790

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
Production	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 production 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

Production 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.