Alloy Steel F9 Round Bar
➡️ F9 | UNS K90941 | EN 1.7386
➡️ ASTM, EN, JIS & International Standards
➡️ Supply Conditions
➡️ Multiple Diameters & Supply Lengths
➡️ Global Export & International Delivery
Country of Origin:
Europe, Japan, USA
Material Type:
Alloy Steel
UNS Number:
K90941
Wr. No.:
1.7386
MTC Available:
EN 10204 3.1
Product Description for Alloy Steel F9 Round Bar
F9 is the ASTM A182 grade designation for a 9% chromium, 1% molybdenum low-alloy steel, UNS K90941. Bar is supplied to ASTM A182 / A182M with dimensions to ASTM A29 / A29M. The same alloy is P9 in ASTM A335 pipe and Grade 9 in ASTM A387 plate.
Raising chromium to 8-10% takes the alloy well beyond F5 in oxidation and sulphidic corrosion resistance, and lifting molybdenum to 0.90-1.10% improves creep strength. The grade is used continuously in refinery and power plant service to around 650 C, where it resists high-temperature sulphur attack better than any of the leaner chromium-molybdenum steels.
Silicon is deliberately specified at 0.50-1.00%, a range rather than a cap, and it adds materially to oxidation resistance.
Bar is supplied annealed, or normalised and tempered with tempering at 675 C minimum. Hardness is controlled to a mandatory 179-217 HBW range.
At this chromium level the steel air hardens readily, so welding demands preheat and post-weld heat treatment without exception, and heavy sections need care during cooling from any heat treatment.
Bar comes in 10 mm to 300 mm, hot-finished or cold-finished. The steel is ferromagnetic and machines reasonably well when ordered in the annealed condition.
Do not confuse F9 with F91. They differ in far more than the digit, and are not interchangeable.
Hardness sits in a mandatory 179-217 HBW band, noticeably higher at the floor than F5, which reflects the stronger alloy content.
Typical work is refinery heater and piping hardware, valve bodies and stems, flange stock and hot fasteners.
Common Applications of Alloy Steel F9 Round Bar
➡️ Machined shafts, spindles, valve stems, pump sleeves and pins for food, beverage, dairy and pharmaceutical equipment, where the passive chromium oxide film resists both product acids and caustic clean-in-place chemicals.
➡️ Fasteners, studs, bolts, threaded rod and anchor components produced from bar stock, chosen for corrosion resistance combined with the ductility needed for cold heading and thread rolling.
➡️ Chemical, water treatment and general process plant parts such as agitator shafts, flange blanks, nozzles and support components handling water, steam and mildly corrosive media free of significant chlorides.
➡️ Architectural and structural hardware including handrail stanchions, balustrade fittings, tension rods and bollards, where a bright ground or polished bar finish provides both appearance and low maintenance.
International Equivalent Grade for Alloy Steel F9 Round Bar
Standard
Country / Region
Grade
UNS
USA
UNS K90941
ASTM A182 / A182M
USA
Grade F9
ASTM A335 / A335M
USA
Grade P9 (seamless pipe)
ASTM A387 / A387M
USA
Grade 9 (plate)
EN 10216-2
Europe / EU
X11CrMo9-1 (1.7386)
DIN 17175
Europe / EU
1.7386 (X11CrMo9-1)
Technical Specification for Alloy Steel F9 Round Bar
Specification
Value
Unit
Material
Alloy steel
-
Grade
F9 / UNS K90941 / 1.7386
-
Product Form
Round bar / rod
-
Standard
ASTM A182 / A182M Grade F9
-
Diameter
10 - 300 (typical supply range)
mm
Length
3 - 6 (random), or cut to length
m
Manufacturing Process
Hot rolled or forged, annealed or normalised and tempered
-
Production Route
EAF or BOF with ladle refining, continuous cast or ingot
-
Surface Finish
Hot-rolled, rough-turned, peeled, smooth-turned, centreless ground
-
Heat Treatment / Delivery Condition
Annealed at 955 C furnace cooled, or normalised at 955 C and tempered at 675 C minimum
-
Tolerance Standard
ASTM A29 / A29M
-
Density
7.78 (typical)
g/cm3
Melting Range
1425 - 1510 (typical)
C
Thermal Conductivity at 100 C
30.0 (typical)
W/m.K
Coefficient of Thermal Expansion (20-100 C)
11.7 (typical)
um/m.C
Specific Heat (0-100 C)
460 (typical)
J/kg.K
Electrical Resistivity at 20 C
0.55 (typical)
uOhm.m
Modulus of Elasticity at 20 C
200 (typical)
GPa
Magnetic Properties
Ferromagnetic in all conditions
-
Maximum Service Temperature
650 (typical, continuous)
C
Testing / Inspection Standard
ASTM A370 for mechanical testing, ASTM A182 for hardness verification
-
Certification / Inspection Documents
EN 10204 3.1 or 3.2 mill test certificate
-
Technical Specifications
Get the key technical specifications for Alloy Steel F9 Round Bar
Buy to ASTM A182 / A182M as Grade F9, with dimensional tolerance, straightness and surface condition from ASTM A29 / A29M rather than the stainless standard A484.
Delivery is either annealed or normalised and tempered, with tempering at 675 C minimum after normalising from 955 C, the same minimum tempering temperature ASTM A182 sets for F5. Hardness is a mandatory 179-217 HBW range, and the floor of 179 HBW is noticeably higher than F5’s 143 HBW, reflecting the stronger alloy.
At 8-10% chromium the steel air hardens readily. Any cooling from above the transformation temperature will produce martensite in the outer layers of a section, so heat treatment of heavy bar has to be controlled and welding cannot be attempted without preheat of roughly 200-300 C, maintained interpass temperature, and mandatory post-weld heat treatment.
One caution worth repeating at order stage: F9 and F91 are entirely different materials despite the similar designation. F91 is a modern normalised-and-tempered martensitic grade with vanadium, niobium and controlled nitrogen, and it is not a variant of F9. Substituting one for the other has caused serious problems in power plant work.
Chemical Composition for Alloy Steel F9 Round Bar
Element
Symbol
Min
Max
Unit
Carbon
C
-
0.15
%
Manganese
Mn
0.30
0.60
%
Silicon
Si
0.50
1.00
%
Phosphorus
P
-
0.030
%
Sulfur
S
-
0.030
%
Chromium
Cr
8.00
10.00
%
Molybdenum
Mo
0.90
1.10
%
Iron
Fe
Balance
-
%
Chemical Composition
View the chemical composition and applicable material limits for Alloy Steel F9 Round Bar
Chromium at 8.00-10.00% is roughly double the F5 level and it is what the grade is bought for. In hot hydrocarbon streams containing sulphur, corrosion rate falls sharply as chromium rises, and at 9% the improvement over 5% chromium steel is substantial. The same chromium gives good scaling resistance to around 650 C. It still does not make the steel stainless, since a passive film needs roughly 10.5%, so wet service will corrode it.
Molybdenum at 0.90-1.10% carries the creep strength, higher than the 0.44-0.65% in F5. It strengthens the solid solution and forms carbides that resist coarsening during long exposure, which is what keeps the steel from sagging under sustained load at temperature.
Silicon at 0.50-1.00% is specified as a range with a floor, unlike most low-alloy steels where it is simply capped. That deliberate minimum contributes to oxidation resistance and is one of the distinguishing features of the grade.
Carbon is capped at 0.15%, giving strength through carbide formation while keeping the steel weldable with proper preheat.
Manganese at 0.30-0.60% deoxidises and adds hardenability. Phosphorus and sulphur are each limited to 0.030% to protect creep ductility and resistance to temper embrittlement.
Mechanical Properties for Alloy Steel F9 Round Bar
Mechanical Property
Value
Unit
Tensile Strength
585
MPa (minimum)
Yield Strength 0.2% Proof
380
MPa (minimum)
Elongation in 50 mm
20
% (minimum)
Reduction of Area
40
% (minimum)
Hardness
179 - 217
HBW (specified range, mandatory)
Modulus of Elasticity
200
GPa (typical)
Mechanical Properties
Check the key mechanical properties and performance requirements of Alloy Steel F9 Round Bar
These are the ASTM A182 / A182M requirements for Grade F9, tested to ASTM A370. Tensile, proof strength, elongation and reduction of area are minima, while hardness is a mandatory range with a floor as well as a ceiling.
Strength sits clearly above F5, at 585 MPa minimum tensile against 485 MPa and 380 MPa minimum proof strength against 275 MPa. That reflects the higher chromium and molybdenum and the higher minimum tempering temperature.
The 179 HBW floor is the figure to watch on incoming material. Below it the steel has been over-tempered, its carbides have coarsened, and the creep strength it was specified for is compromised, even though a room-temperature tensile test may still pass. The 217 HBW ceiling confirms tempering went far enough for adequate toughness and machinability.
For any service above about 400 C the room-temperature figures are not the design basis. Creep-rupture data and ASME BPVC allowable stresses for the grade govern, and they fall away steeply as temperature climbs towards the 650 C practical ceiling.
ASTM A182 sets no mandatory Charpy requirement for F9, but impact testing at the design temperature is a common supplementary requirement for heavy sections.
Dimension / Sizes for Alloy Steel F9 Round Bar
Dimension / Size
Value
Unit
Diameter
10 - 300
mm
Standard Length
3 - 6 (random / mill lengths)
m
Custom Length
Cut to length available on request
-
Diameter Tolerance
Per ASTM A29 / A29M, varies with size and finish
-
Length Tolerance
Per ASTM A29 / A29M or as agreed at order
-
Straightness Tolerance
Per ASTM A29 / A29M or as agreed at order
-
End Condition
Square cut, chamfered, or as ordered
-
Surface Finish
Hot-rolled, rough-turned, peeled, smooth-turned, centreless ground
-
Available Size Range
10 - 300, larger diameters by forging on enquiry
mm
Cut-to-Length Availability
Available
-
Dimensional Standard
ASTM A29 / A29M
-
Dimensions & Sizes
Explore available diameters, lengths, and dimensional requirements for Alloy Steel F9 Round Bar
Pricing for Alloy Steel F9 Round Bar
Round Bar Prices are generally quoted per kilograms or meters tonnes and can fluctuate with the global raw material and market prices. The final price will depend on a variety of factors, including the grade size, diameter, length, surface finish, the quantity and whether the bars are cut to length or in standard lengths.
For smaller quantities, we can also quote per metre or per piece basis once the required dimensions have been confirmed. Container-loads or orders that are larger in size are typically priced per tonne, based upon the specifications required and the supply conditions.
Please provide your desired dimensions, grades, length number, and end for a current quote including the lead time applicable and details for certification.
Pricing
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Why Choose Us
Euro Steel Bars is an international distributor, stockist and exporter of stainless round steel bars that cover carbon, stainless alloy, special grades. We stock a variety of sizes and grades. We guarantee every order with mill test certificates as well as full quality-assurance documentation. Our name speaks to our roots: European-sourced materials that is backed by the certificates and rigor that buyers from Asia as well as the Gulf and Africa are looking for.
Each bar we deliver is accompanied by EN 10204 3.1 mill test certificates as well as complete documentation of quality, so what you receive corresponds to what’s written in the documents. We carry a selection of sizes and grades ready for transport, and cut length upon the request of customers, which results in quicker lead times, whether you’re ordering just a one-off spec or a complete project tonnage.
We operate an actual wholesale business that is that is supported with an internationally-operated supply chain therefore we are able to serve fabricators sourcing one grade the same way in the same way as an EPC contractor who is placing a large order. Our clients include manufacturers, fabricators EPC construction companies, engineers oil and gas projects as well as construction companies. we design our inventory as well as documentation to show what buyers need to bring projects forward.
Our customers trust us across Qatar, Oman, Bahrain, Kuwait, Jordan, Malaysia, Singapore, Thailand, Taiwan, Turkey, Italy and South Africa. If you’re looking to source an Gulf energy project, or a construction project within Southeast Asia, you get the same quality of certified material, the exact documentation, and the exact delivery procedure.
Frequently Asked Questions
What is Alloy Steel F9 Round Bar?
What is the difference between F9 and F91?
What standard does Alloy Steel F9 Round Bar comply with?
What are the equivalent grades of Alloy Steel F9 Round Bar?
What are the key mechanical properties of Alloy Steel F9 Round Bar?
Why does F9 need a higher tempering temperature than F5?
Can Alloy Steel F9 Round Bar be welded?
What sizes and lengths are available?
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