F44 Super Austenitic Stainless Steel Round Bar S31254 1.4547 Marine ISO 9001

Product Description

Product Description

F44 Super Austenitic Stainless Steel Round Bar (UNS S31254 / 1.4547)

6% Molybdenum super-austenitic grade for seawater, desalination and chemical process service

1. Product Introduction

F44, also designated UNS S31254, EN 1.4547 and widely known by the trade name 254SMO, is a high-alloy super austenitic stainless steel engineered for chloride-rich and acidic environments. Its typical balance of about 20% chromium, 18% nickel, 6% molybdenum and added nitrogen gives a Pitting Resistance Equivalent (PREN) above 42, far beyond that of 316L. This makes F44 the standard choice where ordinary austenitic grades suffer pitting, crevice corrosion or chloride stress cracking. FUSHUN METAL selects the melt chemistry toward the upper half of the chromium and molybdenum range to secure the highest PREN for long service life.

FUSHUN METAL supplies F44 as round bar, flat bar and strip for the most demanding sectors: seawater and ballast systems, reverse-osmosis desalination, chemical processing, pulp bleaching, flue-gas desulfurization (FGD) and offshore oil and gas. FUSHUN METAL melts the grade from selected raw materials and verifies every heat under its ISO 9001 quality system, so buyers receive consistent chemistry, dimension and corrosion performance lot after lot. FUSHUN METAL keeps F44 in stock across the common sizes so delivery lead times stay short for repeat buyers.

At FUSHUN METAL the grade is produced in an electric-arc furnace, refined by AOD and VOD to ultra-low carbon and sulfur, then continuous-cast and hot-rolled under tight thermal schedules. Each solution-annealed bar is verified by ultrasonic testing and positive material identification before release, all within the FUSHUN METAL ISO 9001 management system that covers melting, rolling, heat treatment and final inspection.

2. Equivalent Grade Designations

F44 is listed under several national and international systems. FUSHUN METAL stocks material dual-certified to ASTM and EN so drawings calling any of the codes below are fully interchangeable. This lets procurement teams specify by the standard familiar to their project without changing the underlying alloy.

Standard	Grade / Designation
UNS	S31254
ASTM	A182 F44 (forged), A276 / A479 S31254 (bar)
EN	1.4547 (X1CrNiMoCuN20-18-7)
DIN (W.Nr.)	1.4547 / X1CrNiMoCuN20-18-7
AFNOR (NF)	Z1 CNDU 20.18.06 Az
BS	254 SMO
SS (Sweden)	2378
JIS / GOST	No direct single-grade equivalent

3. Typical Applications

FUSHUN METAL F44 bar is machined and forged into the following service-critical components. The high strength lets designers down-gauge compared with 316L, saving weight and cost in fabricated assemblies.

• Marine & Offshore: seawater pump shafts, ballast water pipes, firewater deluge nozzles, propeller shafts, platform handrails, seawater cooling lines.
• Desalination: SWRO high-pressure piping, evaporator tubes, pump casings, brine heater tubes, heat-exchanger tubes.
• Chemical Processing: chloride process vessels, tall-oil distillation columns, bleaching tanks, heat-exchanger tubes, reactor agitators.
• Pulp & Paper: bleach washers, diffusion washers, bleach tower internals, washer drums.
• Flue-Gas Desulfurization: absorber spray headers, scrubber stages, inlet ducts, demister frames.
• Oil & Gas: manifolds, chokes, valve stems, subsea components, NORSOK M-650 firewater systems.
• General: hydraulic and instrumentation tubing, fasteners, flanges and fittings.

Because F44 keeps good toughness down to cryogenic temperatures and welds with common processes, FUSHUN METAL bars are also chosen for LNG-adjacent and sour-service parts where 316L would be undersized or fail by chloride attack.

4. Supply Forms and Dimensions

FUSHUN METAL rolls and finishes F44 in a wide size range to cover both standard and heavy-engineered requirements. Large diameters up to 500 mm allow FUSHUN METAL to supply near-net-shape blanks that reduce customer machining time and scrap.

• Hot Rolled Round Bar: diameter 6 mm to 500 mm, length up to 12,000 mm (cut to length available).
• Hot Rolled Flat Bar: thickness 3 mm to 60 mm, width 12 mm to 400 mm.
• Strip / Coil: thickness 0.5 mm to 6 mm, width up to 600 mm.
• Forged Blocks & Rings: custom shapes per drawing.

Delivery Condition: Solution annealed (1120-1200 deg C, water quenched) and pickled as standard; bright turned, peeled or ground on request. FUSHUN METAL controls the whole route - EAF melting, AOD/VOD refining, continuous casting, hot rolling, solution annealing, pickling - then releases each heat only after ultrasonic testing and positive material identification (PMI). Diameter tolerance follows ASTM A484 and EN 10060; bars are bundled, strapped and wrapped with VCI paper for export.

Surface Condition: black (as-rolled), pickled (acid cleaned), bright turned or peeled. All finishes are supplied under the FUSHUN METAL ISO 9001 quality system with EN 10204 3.1 mill certificate. FUSHUN METAL records heat number, dimensions and test results so every bar is fully traceable to its melt.

5. Chemical Composition

Typical ladle analysis (weight percent) to ASTM A479 / EN 10088-3 (grade 1.4547). FUSHUN METAL reports the actual heat analysis on every certificate.

Element	C	Si	Mn	P	S	Cr	Ni	Mo	Cu	N
Min	-	-	-	-	-	19.50	17.50	6.00	0.50	0.18
Max	0.020	0.80	1.00	0.030	0.010	20.50	18.50	6.50	1.00	0.22

Iron (Fe) is the balance. PREN = Cr + 3.3 x Mo + 16 x N, typically above 42.

FUSHUN METAL checks the actual composition of every heat with optical emission and XRF spectrometers, confirming the 6% molybdenum and controlled nitrogen that drive the PREN above 42 before any bar is shipped.

6. Mechanical Properties

Room-temperature properties in the solution-annealed condition, per ASTM A182 F44 / A479 S31254. FUSHUN METAL tensile-tests and hardness-checks every batch before shipment.

Property	Minimum	Typical Range
Tensile Strength Rm	650 MPa	680 - 850 MPa
Yield Strength Rp0.2	300 MPa	310 - 450 MPa
Elongation A	35 %	40 - 50 %
Reduction of Area	50 %	55 - 65 %
Hardness (Brinell)	220 HB max	180 - 210 HB
Impact Toughness (RT)	100 J typ.	excellent sub-zero

Heat treatment: solution anneal 1120-1200 deg C then rapid water quench. F44 is not hardenable by heat treatment.

In service F44 also shows strong resistance to fatigue and good impact toughness at sub-zero temperature, and against warm seawater it outlasts 316L by several times - a difference that pays back the material premium over plant lifetime. FUSHUN METAL tensile-tests and hardness-checks every batch, and all values are reported on the mill certificate for client verification.

FUSHUN METAL - ISO 9001 certified manufacturer of super austenitic stainless steel bars, delivering verified F44 (UNS S31254 / 1.4547) with full mill test reports for global marine, desalination and chemical projects.

Detailed Photos