Steel A182 F12 Cl.1-SR (Stress relieved)
Heat-treated state
ASTM A182 F12 Cl.1 · UNS K11562
Condition of welded assemblies after mandatory PWHT; hardness of HAZ drops below 225 HV, properties essentially those of the annealed base metal.
Values for the SR condition
Other A182 F12 Cl.1 tempers and conditions
A182 F12 Cl.1 is listed in 3 conditions; see the grade overview at A182 F12 Cl.1.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SRThis page Stress relieved | Condition of welded assemblies after mandatory PWHT; hardness of HAZ drops below 225 HV, properties essentially those of the annealed base metal. | 255 | 450 | 30 | 135 HB | 7.8 % IACS |
AnnealedDefault Annealed (A182 F12 Class 1 as-specified condition) | Standard supply condition for F12 Cl.1 flanges and fittings: full or isothermal anneal, lowest hardness (≤156 HBW), best machinability and toughness. | 265 | 460 | 30 | 140 HB | — |
Normalized and tempered | Pick when higher strength and a finer, more uniform structure are wanted (matches A182 F12 Cl.2 / A335 P12 pipe practice) while keeping creep performance. | 320 | 520 | 26 | 170 HB | — |
What is A182 F12 Cl.1-SR?
A182 F12 Cl.1-SR is A182 F12 Cl.1 heat treated to SR — condition of welded assemblies after mandatory PWHT; hardness of HAZ drops below 225 HV, properties essentially those of the annealed base metal. A182 F12 Cl.1-SR has a yield strength of 255 MPa (37 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 93% of steel grades. Elongation at break is 30% and the elastic modulus is 207 GPa (30 Msi). A182 F12 Cl.1-SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). Annealed is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 155 MPa·√m (141.1 ksi·√in), better than 97% of steel grades
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
- Forms and bends easily — 62/100, better than 78% of steel grades
Limitations
- Low strength — 255 MPa (37 ksi), worse than 93% of steel grades
A182 F12 Cl.1-SR properties
Typical room-temperature values for A182 F12 Cl.1-SR; 22 are specific to this condition. Other listed values are A182 F12 Cl.1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A182 F12 Cl.1-SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
A182 F12 Cl.1-SR has a yield strength of 255 MPa (37 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 93% of steel grades. Elongation at break is 30% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A182 F12 Cl.1-SR is rated for continuous service to 550°C (1,022 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A182 F12 Cl.1-SR conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of A182 F12 Cl.1-SR takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability8
A182 F12 Cl.1-SR's machinability is good (62/100, better than 89% of steel grades); weldability good (62/100); formability good (62/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A182 F12 Cl.1-SR
Is A182 F12 Cl.1 easy to machine?
Machines like annealed 4130-class steel at ~65 % of 1212; use rigid setups, sharp carbide and good coolant to avoid work-hardened skin on threads and flange facings.
Can A182 F12 Cl.1 be welded?
Weldable with matched 1.25Cr-0.5Mo consumables (E8018-B2 / ER80S-B2); preheat 150–250 °C, interpass control and PWHT at ~700–730 °C are required to soften the HAZ and avoid hydrogen cracking.
Can A182 F12 Cl.1 be formed, bent or molded?
Forged hot at 1050–1200 °C with finishing above 900 °C, then annealed or normalized+tempered; cold forming is limited by high yield-to-tensile ratio and springback.
What surface finishes work on A182 F12 Cl.1?
Not anodizable — protect with shop primer, phosphate, zinc/aluminium metallizing, or insulation-jacketing; polished surfaces oxidize quickly and need oiling.
A182 F12 Cl.1 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CClass 1 | 0.05 – 0.15 | 0.11 |
| Mn | 0.3 – 0.61 | 0.45 |
| Si | ≤ 0.5 | 0.25 |
| P | ≤ 0.05 | 0.02 |
| S | ≤ 0.05 | 0.02 |
| Cr | 0.8 – 1.25 | 1 |
| Mo | 0.44 – 0.65 | 0.52 |
| Fe | balance | — |
A182 F12 Cl.1-SR — frequently asked
What is A182 F12 Cl.1-SR used for?
A182 F12 Cl.1-SR is typically used for boiler flanges, pressure vessel nozzles and valve bodies. In short: lower-alloy Cr-Mo forging; good machinability for Cr-Mo; creep service to 550 °C.
What is the yield strength of A182 F12 Cl.1-SR?
A182 F12 Cl.1-SR has a typical yield strength of 255 MPa (37 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 93% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is A182 F12 Cl.1-SR easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machines like annealed 4130-class steel at ~65 % of 1212; use rigid setups, sharp carbide and good coolant to avoid work-hardened skin on threads and flange facings.
Can A182 F12 Cl.1-SR be welded?
Yes — weldability is rated good (62/100). Weldable with matched 1.25Cr-0.5Mo consumables (E8018-B2 / ER80S-B2); preheat 150–250 °C, interpass control and PWHT at ~700–730 °C are required to soften the HAZ and avoid hydrogen cracking.
What surface finishes work on A182 F12 Cl.1-SR?
Not anodizable — protect with shop primer, phosphate, zinc/aluminium metallizing, or insulation-jacketing; polished surfaces oxidize quickly and need oiling.
Can A182 F12 Cl.1-SR be formed, bent or molded?
Forged hot at 1050–1200 °C with finishing above 900 °C, then annealed or normalized+tempered; cold forming is limited by high yield-to-tensile ratio and springback.
What is the maximum service temperature of A182 F12 Cl.1-SR?
A182 F12 Cl.1-SR is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A182 F12 Cl.1 Annealed and A182 F12 Cl.1-SR?
Annealed is the default condition — standard supply condition for F12 Cl.1 flanges and fittings: full or isothermal anneal, lowest hardness (≤156 HBW), best machinability and toughness. SR: condition of welded assemblies after mandatory PWHT; hardness of HAZ drops below 225 HV, properties essentially those of the annealed base metal. Yield strength is 265 MPa in Annealed versus 255 MPa in SR.
Sources
- ASTM A182/A182M — Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Fittings, Valves and Parts — ASTM International (2023)
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service (P12) — ASTM International (2022)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- GB/T 5310 / GB/T 3077 (15CrMo) — SAC (2017)
- API RP 941 — Steels for Hydrogen Service at Elevated Temperatures — API (2016)
- SMM / Mysteel (2025)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.