Alloy steel · UNS K41545 · W.Nr. 1.7362 · 5Cr-½Mo · ASTM A182 F5 / A336 F5 · ASME SA-182 / SA-336
ASTM A182 F5 and A336 F5 forgings
Seamless rolled rings, flanges, tube sheets, valve bodies, discs, shafts, sleeves and round bars, open-die forged to your drawing in F5 (UNS K41545) and supplied annealed or normalized and tempered with an EN 10204 3.1 or 3.2 certificate.
ASTM A182 Grade F5 and ASTM A336 Grade F5 are the forging grades of 5Cr-½Mo alloy steel, UNS K41545: a ferritic chromium-molybdenum steel with 4.00–6.00% chromium, 0.44–0.65% molybdenum and carbon held to 0.15% maximum. The main reason to specify it is resistance to high-temperature sulfidic corrosion in refinery service. Chromium at 4–6% forms a protective sulfide and oxide scale that slows corrosion in a hot sulfur-bearing stream, and molybdenum maintains creep strength at operating temperature. Strength is moderate: F22 and F91 both carry more load above 500 °C. F5 is normally selected where corrosion rather than applied stress governs the design.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The plant forges F5 to customer drawings: seamless rolled rings to 3,000 mm outside diameter, tube sheets and discs to Ø2,500 mm, valve bodies, flanges, shafts, sleeves and bars, in single pieces to 10,000 kg. Parts are heat treated to ASTM A182 or A336, ultrasonically tested and certified to EN 10204 3.1 or 3.2. For a quotation, send a drawing to sales@steelforgepieces.com or call +86 189 2135 9659.
Key data
F5 at a glance
- Grade
- F5. Also written Grade F5, Gr. F5, A182-F5, SA182 F5, SA-336 F5, 5Cr-½Mo
- UNS number
- K41545
- Werkstoff / EN
- 1.7362 (X12CrMo5), nearest European designation
- Alloy family
- Ferritic chromium-molybdenum (chrome-moly) alloy steel; air hardening
- Forging standards
- ASTM A182/A182M F5 and ASME SA-182 F5 (piping components); ASTM A336/A336M F5 and ASME SA-336 F5 (pressure and high-temperature vessel parts)
- Same chemistry, other forms
- Pipe A335 P5 · tube A213 T5 · fittings A234 WP5 · castings A217 C5 · plate A387 Gr. 5 · bolting A193 B5
- Delivery condition
- Annealed, isothermally annealed, or normalized and tempered
- Defining strength
- High-temperature sulfidic corrosion resistance; resistance to high-temperature hydrogen attack
- Flange temperature rating
- To 649 °C (1200 °F) in the ASME B16.5 tables
- ASME Section IX
- P-No. 5A, Group 1. Preheat and PWHT required
- Density
- 7.78 g/cm³ (0.281 lb/in³)
- Certification
- EN 10204 3.1 standard; 3.2 third-party witnessed on request
- Forged by
- Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu Province, China
What F5 is, and when to specify it
Above roughly 260 °C, sulfur compounds in crude and in cracked streams attack steel directly. The corrosion rate depends on the chromium content of the steel and on the sulfur level in the stream. Carbon steel corrodes rapidly in this service. At 1¼Cr (F11) and 2¼Cr (F22) the rate is lower but still significant. At 4–6% chromium the scale becomes protective enough for long-term service, which is why F5 is used in these positions.
Molybdenum at 0.44–0.65% provides solid-solution and carbide strengthening, which keeps useful creep strength into the 500–600 °C range. Without it the part would relax under load at the temperature where its corrosion resistance is needed. Carbon is held to 0.15% maximum for weldability. 5Cr steel is air hardening, and higher carbon raises the hardness of the heat-affected zone and increases the risk of hydrogen cracking.
Strength is the limitation. A182 F5 is accepted at 485 MPa minimum tensile and 275 MPa minimum yield, below F9, F91 and the higher classes of F11 and F22. For the same duty an F5 section comes out thicker than an F22 section.
Specify F5 when
- The stream carries sulfur compounds above about 260 °C: crude and vacuum units, hydrotreater reactor loops, catalytic reformers, coker and FCC circuits.
- A carbon steel, F11 or F22 component in the same position has already thinned or failed by sulfidation.
- The service sits in the hydrogen-partial-pressure and temperature region where API 941 puts 5Cr-½Mo above the plain carbon and low-chrome curves.
- The part must match an existing 5Cr line: A335 P5 pipe, A213 T5 tube, A217 C5 valve castings.
- The design allows a thicker section in return for a lower corrosion allowance.
Specify another grade when
- Creep strength governs the section rather than corrosion. Use F22 Class 3, F9 or F91.
- Service is above about 600 °C under load. F91 (9Cr-1Mo-V) carries far higher allowable stress.
- The stream is aqueous and chloride-bearing rather than hot and sulfidic. A ferritic chrome-moly steel gives no benefit; use a stainless or nickel grade.
- Naphthenic acid corrosion dominates at high total acid number. Chromium alone does not control it; molybdenum-bearing austenitic grades such as 316L or 317L are normally used instead.
- The position is unheated and non-corrosive. Carbon steel A105 or A350 LF2 costs a fraction as much.
Open-die forged product forms in F5
Chemical composition of F5 (UNS K41545)
The limits below are the ASTM A182/A182M Grade F5 requirements in weight percent, with the ASTM A336/A336M, A335 P5 and A213 T5 limits shown alongside where they differ. The highlighted row is the chromium range that separates F5 from the lower-chrome grades.
| Element | ASTM A182 F5 | A335 P5 / A213 T5 | Role in the alloy |
|---|---|---|---|
| Chromium (Cr) | 4.00–6.00 | 4.00–6.00 | Forms the protective scale against high-temperature sulfidic corrosion and oxidation. |
| Molybdenum (Mo) | 0.44–0.65 | 0.45–0.65 | Solid-solution and carbide strengthening; holds creep strength into the 500–600 °C range. |
| Carbon (C) | 0.15 max | 0.15 max | Held low for weldability. F5a is the 0.25% max carbon variant. |
| Manganese (Mn) | 0.30–0.60 | 0.30–0.60 | Deoxidiser; combines with residual sulfur; adds hardenability. |
| Silicon (Si) | 0.50 max | 0.50 max | Deoxidiser; contributes to oxidation resistance of the scale. |
| Nickel (Ni) | 0.50 max | — | Residual. Capped so the steel stays ferritic and temper-embrittlement risk is contained. |
| Phosphorus (P) | 0.030 max | 0.025 max | Residual. Drives temper embrittlement; tighter limits are ordered for long-life hot service. |
| Sulfur (S) | 0.030 max | 0.025 max | Residual. Controlled for through-thickness ductility and weld soundness. |
| Iron (Fe) | balance | balance | Base element. |
Every heat is supplied with a ladle analysis on the mill certificate; product analysis on the finished forging is added on request. Tighter residual limits, such as a J-factor or X-bar restriction for temper-embrittlement control, are quoted where the purchase order calls for them. Composition limits compiled by Jiangyin Jiangnan Metal Co., Ltd. from ASTM A182/A182M, A336/A336M, A335/A335M and A213/A213M; verify against the edition cited on your order.
Mechanical properties of F5 forgings
F5 carries two different sets of acceptance values depending on which specification governs the order. ASTM A182 covers forged piping components and demands the higher strength; ASTM A336 covers forgings for pressure vessels and high-temperature parts and accepts a lower, banded tensile range. Neither set is stricter overall; they are written for different components. State the specification on the purchase order, because the certificate is issued against it.
| Property | ASTM A182 F5 / SA-182 F5 | ASTM A336 F5 / SA-336 F5 |
|---|---|---|
| Tensile strength | 485 MPa (70 ksi) min | 415–585 MPa (60–85 ksi) |
| Yield strength, 0.2% offset | 275 MPa (40 ksi) min | 205 MPa (30 ksi) min |
| Elongation in 50 mm (2 in) | 20% min | 20% min |
| Reduction of area | 35% min | 35% min |
| Hardness | 143–217 HBW | Per specification / purchase order |
| Impact testing | Supplementary requirement | Charpy V-notch per the specification and order |
Acceptance is governed by the table in the edition of the specification cited on the order, and by the mill test certificate issued with the forging. State the required minimums, the test location and orientation, and any impact requirement on the enquiry and they will be confirmed with the quotation.
Behaviour at temperature
Short-term tensile strength falls steadily with temperature, and above roughly 450–500 °C the design is governed by creep and stress rupture rather than by the room-temperature minimums. Do not size a hot F5 component from the 485 MPa figure. Take the allowable stress for the design temperature from ASME BPVC Section II Part D, from ASME B31.3, or from the code that governs the equipment. Where a design needs creep or stress-rupture data at a specific temperature and design life, request it with the enquiry.
Temper embrittlement. Like other Cr-Mo steels, 5Cr-½Mo can lose toughness after long exposure in the approximate 340–590 °C range, with the rate governed by residual phosphorus, tin, antimony and arsenic. For equipment designed for decades of hot service, specify restricted residuals and a J-factor or X-bar limit on the purchase order at the time of enquiry. It cannot be added after the heat is melted.
Physical properties of F5
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.78 g/cm³ | 0.281 lb/in³ |
| Modulus of elasticity | ≈207 GPa | ≈30 × 106 psi |
| Specific heat capacity | ≈470 J/kg·K | ≈0.112 Btu/lb·°F |
| Thermal conductivity, 100 °C | ≈37 W/m·K | ≈21 Btu/h·ft·°F |
| Mean thermal expansion, 20–300 °C | ≈11.6 µm/m·°C | ≈6.4 µin/in·°F |
| Magnetic response | Ferromagnetic | Ferromagnetic |
Nominal values compiled for design screening. Where a physical property enters a design calculation, for example a differential-expansion check on a tube sheet, request the figure in writing against the specific temperature rather than taking it from this table.
Heat treatment and delivery condition
5Cr-½Mo is air hardening. A section left to cool in still air from forging temperature transforms to martensite and arrives hard and brittle, well above the 217 HBW limit. Heat treatment after forging is required by the specification and determines whether the part meets its acceptance values.
| Stage | Typical practice | Purpose |
|---|---|---|
| Post-forge cooling | Cool below 538 °C (1000 °F) before heat treating, as ASTM A182 requires | Completes transformation under control before the austenitizing cycle begins |
| Full anneal | Austenitize near 955 °C (1750 °F), then controlled furnace cool | Softest condition; best machinability; lowest residual stress |
| Isothermal anneal | Austenitize, then hold at the transformation temperature and cool | Uniform structure through heavy sections in a shorter cycle |
| Normalize and temper | Austenitize near 955 °C, air cool, then temper at or above the specification minimum, commonly 675 °C (1250 °F) or higher | Higher and more uniform strength than annealing; the usual condition for pressure parts |
| Holding time | Typically 1 hour per 25 mm of section at temperature, minimum 30 minutes | Ensures the centre of a heavy section reaches temperature |
Furnace charts are recorded for every load and issued with the EN 10204 certificate. Exact austenitizing and tempering temperatures are set against the edition of the specification cited on the order and against any customer procedure supplied with the purchase order. Where a simulated post-weld heat treatment cycle is required on the test material, state the temperature, holding time and number of cycles with the enquiry.
F5 compared with F11, F22, F9 and F91
These five chrome-moly forging grades compete for the same hot refinery and power positions and are routinely substituted for one another on drawings. They are separated by chromium content, which governs corrosion, and by strength at temperature, which governs section thickness.
| Criterion | F5 | F11 Cl.2 | F22 Cl.3 | F9 | F91 |
|---|---|---|---|---|---|
| Nominal type | 5Cr-½Mo | 1¼Cr-½Mo | 2¼Cr-1Mo | 9Cr-1Mo | 9Cr-1Mo-V |
| UNS | K41545 | K11572 | K21590 | K90941 | K90901 |
| Chromium | 4.00–6.00% | 1.00–1.50% | 2.00–2.50% | 8.0–10.0% | 8.0–9.5% |
| Tensile, min | 485 MPa | 485 MPa | 515 MPa | 585 MPa | 620 MPa |
| Yield, min | 275 MPa | 275 MPa | 310 MPa | 380 MPa | 415 MPa |
| Hardness | 143–217 HBW | 143–207 HBW | 156–207 HBW | 179–217 HBW | 190–248 HBW |
| Sulfidation resistance | High | Low | Moderate | Very high | Very high |
| Creep strength | Moderate | Moderate | High | High | Highest |
| ASME P-No. | 5A | 4 | 5A | 5B Gr.1 | 15E Gr.1 |
| Fabrication difficulty | Moderate | Low | Moderate | High | High, narrow PWHT window |
| Choose it when | Hot sulfidic corrosion governs and load is moderate | Mild hot service, cost matters | Hydrogen service and creep strength together | Severe sulfidation above F5 capability | Maximum creep strength above 550 °C |
Where corrosion governs the design, F5 is the economical step up from 2¼Cr. Where applied stress at temperature governs, F22 Class 3 or F91 carries more load in a thinner section. F91 is not a drop-in substitution: it has a narrow PWHT window, strict residual limits and hardness controls that add cost and inspection. Comparison compiled by Jiangyin Jiangnan Metal Co., Ltd. from ASTM A182/A182M; verify against the edition in force before finalising a design.
F5 and F5a: check which grade the drawing means
F5 and F5a share the 5Cr-½Mo chemistry and differ only in carbon content. F5 is the 0.15% maximum carbon grade, UNS K41545. F5a is the 0.25% maximum carbon grade, UNS K42544, accepted at roughly 620 MPa (90 ksi) minimum tensile and 450 MPa (65 ksi) minimum yield with a hardness band of 187–248 HBW. Before 1955 the symbol F5 was assigned to the higher-carbon grade; it was reassigned to the low-carbon grade so that the forging designation would line up with the pipe, tube, bolting and fitting specifications. A legacy drawing that calls for F5 may therefore mean present-day F5a. Check the drawing revision date, and state the UNS number on the order so the requirement is unambiguous on the certificate.
F5 equivalent designations and standards
| System | Designation |
|---|---|
| UNS (USA) | K41545 |
| ASTM forging | A182/A182M Grade F5; A336/A336M Grade F5 |
| ASME forging | SA-182 F5; SA-336 F5 |
| Werkstoff Nr. (Germany) | 1.7362, X12CrMo5 (nearest equivalent) |
| GB (China) | 1Cr5Mo (nearest equivalent) |
| JIS (Japan) | G3203 SFVA F5 series; G3458 STPA 25 (pipe), nearest equivalents |
| Common names | 5Cr-½Mo, 5% chrome moly, Grade 5 chrome moly, Type 502 (obsolete AISI designation) |
| Product form | ASTM | ASME | Grade symbol |
|---|---|---|---|
| Forged piping components: flanges, fittings, valves | A182/A182M | SA-182 | F5 |
| Forgings for pressure and high-temperature parts | A336/A336M | SA-336 | F5 |
| Seamless pipe | A335/A335M | SA-335 | P5 |
| Seamless boiler, superheater and heat-exchanger tube | A213/A213M | SA-213 | T5 |
| Wrought welding fittings | A234/A234M | SA-234 | WP5 |
| Castings for pressure-containing parts | A217/A217M | SA-217 | C5 |
| Plate for pressure vessels | A387/A387M | SA-387 | Grade 5, Class 1 / 2 |
| Bolting for high-temperature service | A193/A193M | SA-193 | Grade B5 |
| Nuts for high-temperature service | A194/A194M | SA-194 | Grade 3 |
A piping class written around 5Cr will normally call A335 P5 pipe, A234 WP5 fittings, A182 F5 flanges and valve forgings, and A217 C5 valve castings, so that the whole line carries the same corrosion resistance. Where a vessel component such as a tube sheet, shell course or channel is forged rather than rolled, A336 F5 is the specification that applies. Jiangyin Jiangnan Metal Co., Ltd. produces the forged items in that list; order to the ASTM or ASME designation and the UNS number together.
F5 forgings we produce
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory. Every item below is forged to the customer’s drawing or dimensional sketch. There is no fixed catalogue, no tooling charge and no minimum order quantity by piece.
Seamless rolled rings
Ring-rolled with no weld seam. Rectangular, profiled and stepped sections for exchanger and vessel work.
Forged flanges
Weld neck, slip-on, blind, long weld neck, orifice, girth flanges and channel covers, to ASME B16.5 / B16.47 or to drawing.
Tube sheets and tube plates
Forged, faced and drilled tube sheets and tube-support plates for fixed, stationary and floating heads, front and rear. Weld-overlay clad on request.
Valve components
Valve bodies, body blocks, bonnets, stems, closures, seat rings and wedges for hot refinery and power service.
Discs, disks and blanks
Upset-forged discs for covers, closures, blind ends and machined blanks.
Shafts and spindles
Straight, stepped and eccentric shafts, hubs and housings.
Sleeves, bushes and bushings
Hollow forged, trepanned or bored, thin or heavy wall. Barrels, casings and cases.
Round bars and hollow bars
Forged and peeled or rough turned, cut to length. Reforging stock to A182 or A336 chemistry.
Nozzles and blocks
Self-reinforced (FVC-type) nozzles, long welding neck nozzle necks, headers, blocks and custom shapes to print.
Cylinders and shells
Hollow forged cylinders, shell courses, casings and pipe sections in heavy wall.
Size and weight capability
| Product form | Dimensional range | Unit weight |
|---|---|---|
| Seamless rolled rings | OD 200–3,000 mm, height to 800 mm | 20–8,000 kg |
| Discs and tube sheets | Ø200–2,500 mm, thickness to 600 mm | 30–10,000 kg |
| Round bars | Ø80–800 mm, length to 6,000 mm | 20–6,000 kg |
| Shafts, sleeves, blocks | to 6,000 mm long | to 10,000 kg |
Machining allowance is normally 6–20 mm per surface depending on section size, unless your drawing states otherwise. Finish-machined parts to print are also supplied. Plant equipment: 1 t, 3 t, 5 t and 9 t open-die forging hammers, a 5,000 t hydraulic press, and 3 m and 6 m seamless ring rolling mills. Sizes outside this envelope are quoted on enquiry.
How we make F5 forgings
- Melt and billet verification 5Cr-½Mo stock is electric-arc melted and ladle refined, with vacuum degassing or electroslag remelting added where the customer specification or the service condition calls for improved cleanliness and reduced segregation. Heat chemistry is confirmed by spectrometer against the A182 or A336 limits before any material is heated.
- Open-die forging The billet is soaked and forged on hydraulic presses and hammers, broadly between 1150 °C and 900 °C, with a controlled reduction ratio that closes porosity and develops a wrought grain flow following the part contour. Rings are rolled seamless on the ring mill.
- Controlled post-forge cooling The forging is cooled below 538 °C (1000 °F) before heat treatment, as ASTM A182 requires. This matters more for 5Cr than for a plain carbon steel, because the grade is air hardening.
- Heat treatment Fully annealed, isothermally annealed, or normalized and tempered to the requirement of the governing specification. Furnace charts are recorded for every load and issued with the certificate.
- Rough or finish machining Turned, bored, drilled and faced to your drawing with an agreed machining allowance, or finish machined to final dimensions. Tube sheets are drilled and, where required, weld-overlay clad.
- Non-destructive testing Ultrasonic examination to EN 10228-3, SEP 1921 or ASTM A388 to your nominated class, with magnetic particle or liquid penetrant examination and dimensional inspection as required.
- Certification and despatch EN 10204 3.1 mill certificate as standard; 3.2 with third-party witness (TÜV, BV, LR, SGS, DNV) on request. Hard stamped, preserved and packed for sea or air freight.
Where F5 forgings are used
| Industry | Components forged in F5 |
|---|---|
| Oil refining | Crude and vacuum unit transfer line flanges and fittings, hydrotreater and hydrocracker reactor loop components, catalytic reformer piping forgings, coker and FCC circuit valve bodies and bonnets |
| Petrochemical | Furnace and heater header forgings, hot-stream valve components, nozzle bodies and self-reinforced nozzles on reactors operating in sulfur-bearing service |
| Shell and tube heat exchangers | Fixed, stationary and floating tube sheets, front and rear head components, girth flanges, channel covers, tube-support plates, cladded and weld-overlay tube sheets |
| Valves and flow control | Valve bodies and body blocks, bonnets, stems, closures, seat rings and wedges for gate, globe, check and control valves in hot refinery lines |
| Power generation | Superheater and reheater header forgings, hot piping flanges and fittings, hanger and support hardware in flue-gas paths |
| Pressure vessels | Forged shell courses, heads, nozzles, hubs and reinforcing pads to ASTM A336 F5 for high-temperature vessels |
| Fired heaters | Return bend and header components, tube supports and hanger hardware in sulfur-bearing flue gas |
| Hydrogen service | Piping and vessel components sitting in the API 941 region where 5Cr-½Mo is required against high-temperature hydrogen attack |
All of these positions combine temperature with sulfur. A carbon steel, 1¼Cr or 2¼Cr component in the same service would need either a large corrosion allowance or replacement during the run. Where the same stream is aqueous and chloride-bearing at lower temperature, a ferritic chrome-moly steel gives no benefit and a stainless or nickel grade should be considered.
Welding and machining F5
Welding
5Cr-½Mo is an air-hardening alloy and the welding procedure has to allow for that. The heat-affected zone transforms to martensite on cooling, and the principal risk is delayed hydrogen cracking.
- Use matching AWS B6 consumables: E8018-B6 covered electrodes for SMAW, ER80S-B6 wire for GTAW and GMAW, with the corresponding B6 flux-wire combination for SAW.
- Preheat before welding. ASME B31.3 calls for a minimum of 175 °C (350 °F) for P-No. 5A material. Heavier sections and higher restraint need more.
- Maintain preheat and control interpass temperature continuously through the joint. Do not let the weld cool to ambient between passes.
- Apply post-weld heat treatment, broadly in the 705–760 °C range with the holding time taken from the governing code. Where PWHT cannot immediately follow, apply a hydrogen bake-out and hold the joint warm.
- Keep consumables dry and baked. Hydrogen from damp flux is the usual root cause of cold cracking in 5Cr welds.
- Where a forging will be welded into a line, tell us at enquiry stage: weld-prep geometry, bevel details and a simulated PWHT cycle on the test material can all be built into the order.
Machining
- In the annealed condition F5 machines like a medium-strength low-alloy steel. The 143–217 HBW range is within normal carbide turning practice.
- The chromium content makes the chip more abrasive than a plain carbon steel; expect shorter tool life than on A105 at the same parameters.
- Order the forging close to net shape where the section is heavy. Removing a large allowance from 5Cr costs more in tooling and time than the extra forged weight saves.
- Rough machining before final heat treatment and finish machining afterwards gives the best dimensional stability on long shafts and large tube sheets.
- Deep-hole drilling on tube sheets is done on the drilling line with the pattern taken from the customer drawing or DXF file.
Testing, inspection and certification
- Chemical analysis. Spectrometric ladle analysis on every heat and, on request, product analysis on the finished forging.
- Mechanical testing. Room-temperature tensile, yield, elongation, reduction of area and hardness as standard; elevated-temperature tensile, stress rupture and Charpy V-notch impact testing to your specification.
- Grain size. Determined per ASTM E112 where the order requires it.
- Ultrasonic testing. EN 10228-3, SEP 1921 Class C/D/E, ASTM A388 or your nominated customer class.
- Surface NDT. Magnetic particle examination per ASTM E709 / ASME V Article 7, or liquid penetrant per ASTM E165 / ASME V Article 6.
- Heat treatment records. Furnace charts for every load, issued with the certificate.
- PMI. Positive material identification on the finished part where the order calls for it.
- Certification. EN 10204 3.1 as standard; EN 10204 3.2 witnessed by TÜV, BV, LR, SGS or DNV on request. Full heat traceability and hard stamping.
- Supplementary requirements. NACE MR0175 / ISO 15156 hardness control, restricted residuals for temper-embrittlement control, and simulated PWHT on test material, where stated on the purchase order.
Frequently asked questions about F5
What is ASTM A182 F5 steel?
ASTM A182 Grade F5 is a ferritic chromium-molybdenum alloy steel forging grade containing 4.00–6.00% chromium and 0.44–0.65% molybdenum with carbon held to 0.15% maximum, registered as UNS K41545 and commonly written 5Cr-½Mo. It is specified for flanges, fittings, valves and pressure parts in high-temperature service, above all in refinery units where sulfur compounds in the process stream attack carbon steel. The chromium forms a protective scale that resists high-temperature sulfidic corrosion, and the molybdenum maintains creep strength at operating temperature.
What is the difference between ASTM A182 F5 and ASTM A336 F5?
The chemistry is the same 5Cr-½Mo composition under UNS K41545, but the two specifications cover different parts and set different acceptance values. ASTM A182/A182M covers forged flanges, fittings, valves and parts for high-temperature piping service, and requires a minimum tensile strength of 485 MPa (70 ksi), a minimum yield of 275 MPa (40 ksi) and a hardness of 143–217 HBW. ASTM A336/A336M covers alloy steel forgings for pressure and high-temperature vessel parts such as shells, tube sheets and heads, and specifies a tensile range of 415–585 MPa (60–85 ksi) with a minimum yield of 205 MPa (30 ksi).
Piping components are normally ordered to A182 and vessel components to A336. State which specification governs on the purchase order, because the certificate is written against it.
What does the F5 designation mean, and how does it differ from F5a?
F5 and F5a are both 5Cr-½Mo, separated by carbon content. F5 is the 0.15% maximum carbon grade, UNS K41545. F5a is the 0.25% maximum carbon grade, UNS K42544, which gives higher strength: roughly 620 MPa (90 ksi) minimum tensile against 485 MPa for F5, with a 187–248 HBW hardness range.
Before 1955 the symbol F5 was assigned to the higher-carbon grade, and it was reassigned to the 0.15% carbon grade so the forging designation would line up with the pipe, tube and bolting specifications. A legacy drawing that calls for F5 may therefore mean present-day F5a, so check the drawing revision date and state the UNS number on the order.
What is the chemical composition of F5 (UNS K41545)?
ASTM A182 Grade F5 is limited to 0.15% maximum carbon, 0.30–0.60% manganese, 0.030% maximum phosphorus, 0.030% maximum sulfur, 0.50% maximum silicon, 0.50% maximum nickel, 4.00–6.00% chromium and 0.44–0.65% molybdenum, balance iron. The related pipe and tube grades ASTM A335 P5 and ASTM A213 T5 hold phosphorus and sulfur to 0.025% maximum and quote molybdenum as 0.45–0.65%.
Jiangyin Jiangnan Metal Co., Ltd. supplies a ladle analysis on every certificate and adds product analysis on the finished forging on request.
What are the mechanical properties of ASTM A182 F5 forgings?
ASTM A182 Grade F5 requires a minimum tensile strength of 485 MPa (70 ksi), a minimum yield strength of 275 MPa (40 ksi), a minimum elongation of 20% in 50 mm, a minimum reduction of area of 35%, and a hardness in the range 143–217 HBW. The hardness is a bounded range rather than a floor because F5 is supplied heat treated and must stay machinable and weldable. Values are demonstrated per heat on the mill test certificate.
How is F5 heat treated?
F5 is supplied fully annealed, isothermally annealed, or normalized and tempered. A typical annealing cycle is austenitizing near 955 °C (1750 °F) followed by a controlled furnace cool; a typical normalize-and-temper cycle is austenitizing in the same range, air cooling, then tempering at or above the minimum stated in the specification, commonly 675 °C (1250 °F) or higher.
ASTM A182 also requires the forging to be cooled below 538 °C (1000 °F) after hot working and before heat treatment. 5Cr-½Mo is air hardening, so uncontrolled cooling from forging temperature leaves untempered martensite and a hardness above the 217 HBW ceiling.
What is the maximum service temperature of F5 forgings?
ASME B16.5 rates 5Cr-½Mo flange material to 649 °C (1200 °F) in its pressure–temperature tables, and the allowable pressure falls steeply as that limit is approached. The practical ceiling for a given part is set by the design code, the applied stress and the design life rather than by the grade alone, because creep governs above roughly 450–500 °C. Take the allowable stress from ASME BPVC Section II Part D or the applicable piping code for the exact temperature rather than from the room-temperature minimums.
Why is F5 specified instead of carbon steel or the 1¼Cr and 2¼Cr grades?
Chromium content governs resistance to high-temperature sulfidic corrosion, the dominant wastage mechanism in crude, vacuum, hydrotreater and catalytic reformer service. At 4–6% chromium, F5 corrodes far more slowly than carbon steel, F11 (1¼Cr) or F22 (2¼Cr) in a hot sulfur-bearing stream, and it sits higher on the API 941 curves for resistance to high-temperature hydrogen attack.
F5 is not chosen for strength: F22 and F91 are considerably stronger at temperature. Specify F5 when corrosion governs the design and F22 or F91 when creep strength governs.
How is F5 welded?
Weld 5Cr-½Mo with matching AWS B6 consumables such as E8018-B6 covered electrodes or ER80S-B6 filler wire, and treat it as an air-hardening alloy. Preheat before welding, typically 175 °C (350 °F) minimum for P-No. 5A material under ASME B31.3, hold the interpass temperature under control, and apply post-weld heat treatment in the region of 705–760 °C, with the exact range and holding time taken from the governing code.
Do not let a 5Cr weld cool to ambient without either PWHT or a hydrogen bake-out; delayed cold cracking is the usual failure mode.
Which pipe, tube, plate and casting grades match F5?
The 5Cr-½Mo family runs across product forms as follows: forgings ASTM A182 F5 and A336 F5; seamless pipe A335 P5; seamless tube A213 T5; welding fittings A234 WP5; castings A217 C5; plate A387 Grade 5; bolting A193 Grade B5; nuts A194 Grade 3. The ASME equivalents carry an SA prefix: SA-182 F5, SA-336 F5, SA-335 P5, SA-213 T5 and SA-217 C5. In the European system the nearest designation is Werkstoff 1.7362, X12CrMo5.
What sizes of F5 forgings can you supply?
Jiangyin Jiangnan Metal Co., Ltd. forges F5 seamless rolled rings from 200 to 3,000 mm outside diameter, discs and tube sheets from Ø200 to Ø2,500 mm and up to 600 mm thick, round bars from Ø80 to Ø800 mm and up to 6,000 mm long, and shafts, sleeves and blocks up to 6,000 mm long, with single-piece weights up to 10,000 kg.
Open-die forging needs no dies, so one-off and prototype quantities are economic. There is no tooling charge and no minimum order quantity by piece.
What certification is supplied with F5 forgings?
Every F5 forging ships with an EN 10204 3.1 mill test certificate as standard, reporting heat number, ladle chemical analysis, tensile and yield strength, elongation, reduction of area, hardness, the heat treatment record with furnace charts, and ultrasonic test results. EN 10204 3.2 certification witnessed by a third party such as TÜV, BV, LR, SGS or DNV is available on request at the time of order. Full heat traceability and hard stamping are standard.
How long does an F5 forging take to produce?
Lead time depends on billet availability and on the size of the forging. Simple rings, discs and bars from stock material typically run 30–45 days. Parts needing a new melt, electroslag remelting, heavy machining, low-temperature impact testing or third-party witnessed inspection take longer. Send a drawing and a firm date will be confirmed with the quotation.
Who supplies open-die forged ASTM A182 F5 and A336 F5 parts in China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. It forges ASTM A182 F5, ASME SA-182 F5, ASTM A336 F5 and ASME SA-336 F5 (UNS K41545, 5Cr-½Mo) into seamless rolled rings, flanges, tube sheets, valve bodies and bonnets, discs, shafts, sleeves, hollow bars and round bars to customer drawing, and exports worldwide. Enquiries go to sales@steelforgepieces.com or +86 189 2135 9659, and a written quotation normally follows within one working day.
Request a quotation for F5 forgings
Send a drawing, a sketch, or just the dimensions and quantity. We quote open-die forgings in ASTM A182 F5 and ASTM A336 F5 with no tooling charge and no piece minimum.
Useful details if you have them: grade and governing specification (A182 F5, A336 F5, SA-182 F5, SA-336 F5), product form, dimensions with machining allowance, quantity, delivery condition and heat treatment, NDT class, certificate type (EN 10204 3.1 or 3.2), any supplementary requirement such as NACE MR0175 or restricted residuals, and the required delivery date.
Email your drawing for a quote
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
- Business
- Open-die forging factory
- Address
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone / WhatsApp
- +86 189 2135 9659 (0086-189-2135-9659)
- Website
- www.steelforgepieces.com
- Quotation time
- Normally within one working day
Technical summary
ASTM A182 Grade F5 and ASTM A336 Grade F5 (ASME SA-182 F5 and SA-336 F5, UNS K41545, Werkstoff 1.7362) are the forging grades of 5Cr-½Mo ferritic chromium-molybdenum alloy steel, containing 4.00–6.00% chromium and 0.44–0.65% molybdenum with carbon to 0.15% maximum. A182 F5 is accepted at 485 MPa (70 ksi) minimum tensile strength, 275 MPa (40 ksi) minimum yield, 20% minimum elongation, 35% minimum reduction of area and 143–217 HBW; A336 F5 at 415–585 MPa tensile and 205 MPa minimum yield. The grade is specified for high-temperature sulfidic corrosion resistance in refinery and petrochemical service and is rated to 649 °C (1200 °F) in the ASME B16.5 tables. It is supplied annealed or normalized and tempered, is air hardening, and is classified P-No. 5A Group 1 for welding, requiring preheat and post-weld heat treatment. The same chemistry appears as A335 P5 pipe, A213 T5 tube, A234 WP5 fittings, A217 C5 castings, A387 Grade 5 plate and A193 B5 bolting. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges F5 into seamless rolled rings to 3,000 mm outside diameter, tube sheets and discs to Ø2,500 mm, valve bodies, flanges, shafts, sleeves and bars in single pieces to 10,000 kg, ultrasonically tested and certified to EN 10204 3.1 or 3.2. Contact: sales@steelforgepieces.com, +86 189 2135 9659.