Steel A335 P22 · heat-treated state
Steel A335 P22 Q&T
Properties of the Q&T condition, compared with the other A335 P22 tempers.
Pick liquid quenching plus tempering at 675 °C or above for heavy forgings, valve bodies and hydrocracker shells; uniform tempered bainite gives 500 MPa yield but machinability drops to 44.
What is A335 P22 Q&T?
A335 P22 Q&T is A335 P22 heat treated to Q&T — pick liquid quenching plus tempering at 675 °C or above for heavy forgings, valve bodies and hydrocracker shells; uniform tempered bainite gives 500 MPa yield but machinability drops to 44. A335 P22 Q&T has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 63% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi). A335 P22 Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). HR is the default condition FabDigit quotes; Q&T is available on request or by drawing note.
Advantages
- High service temperature — 580°C (1,076 °F), better than 97% of steel grades
- Tough — resists crack growth — 140 MPa·√m (127.4 ksi·√in), better than 94% of steel grades
A335 P22 Q&T properties
Typical room-temperature values for A335 P22 Q&T — 16 properties are specific to this condition; the rest are grade-level values shared by every A335 P22 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
A335 P22 Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical15
A335 P22 Q&T has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 63% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A335 P22 Q&T is rated for continuous service to 580°C (1,076 °F). It conducts heat at 37 W/m·K (21.4 BTU/hr·ft·°F), worse than 70% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
A335 P22 Q&T conducts electricity at 7.8 % IACS, worse than 58% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of A335 P22 Q&T takes about 33 MJ of energy and emits 2.4 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 30%.
Manufacturability7
A335 P22 Q&T's machinability is fair (44/100, worse than 71% of steel grades); weldability fair (50/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other A335 P22 tempers and conditions
A335 P22 is also supplied in 4 other conditions. The full side-by-side table is on the A335 P22 overview.
- HRDefaultIntermediate hot rolled or hot extruded state only: ASTM A335 requires final delivery annealed or normalised and tempered, so use it for tube blanks and further processing.350 MPa yield · 165 HB
- Q&TPick liquid quenching plus tempering at 675 °C or above for heavy forgings, valve bodies and hydrocracker shells; uniform tempered bainite gives 500 MPa yield but machinability drops to 44.500 MPa yield · 19 HRC
- NormalizedUse after austenitizing at 900–950 °C and air cooling to refine grain and reach 420 MPa yield; hardness climbs to 185 HB with high residual stress, so most piping is tempered afterwards.420 MPa yield · 185 HB
- N&TSpecify normalizing at 900–950 °C plus tempering at not less than 677 °C for thick-wall main steam pipe and headers: 360 MPa yield, 580 °C service, best creep-toughness balance.360 MPa yield · 160 HB
- AnnealedChoose the full or isothermal annealed pipe when field bending and welding matter most: 140 HB and the best formability, at only 310 MPa yield and 490 MPa tensile.310 MPa yield · 140 HB
Working with A335 P22 Q&T
Is A335 P22 easy to machine?
Annealed P22 cuts much like annealed 4140, about 55–60 % of AISI 1212; use coated carbide at moderate speed with a healthy feed, and watch for work hardening and built-up edge at depth.
Can A335 P22 be welded?
Weld by GTAW or SMAW with matching Cr-Mo consumables (ER90S-B3, E9015-B3); preheat 200–250 °C, hold interpass below 350 °C, and apply 700–760 °C post-weld hydrogen-release and stress-relief heat treatment to prevent hydrogen cracking and a hard, brittle HAZ.
Can A335 P22 be formed, bent or molded?
Prefer hot bending and forming at 900–1000 °C, then re-normalize and temper; cold bending requires large bend radii followed by a stress-relief cycle.
What surface finishes work on A335 P22?
Not anodizable; shot blast and apply high-temperature heat-resistant coating, aluminizing or diffusion coating, or zinc plating for low-temperature duty, to control atmospheric and flue-gas side oxidation.
A335 P22 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 |
|---|---|---|
| C | 0.05 – 0.15 | 0.11 |
| Mn | 0.3 – 0.6 | 0.45 |
| Si | ≤ 0.5 | 0.25 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.03 | 0.01 |
| Cr | 1.9 – 2.6 | 2.25 |
| Mo | 0.87 – 1.13 | 1 |
| Fe | balance | — |
A335 P22 Q&T — frequently asked
What is A335 P22 Q&T used for?
A335 P22 Q&T is typically used for main steam piping, superheater and reheater headers, boiler header stubs and tube connections, hydrocracker and hydrotreater piping, hot petrochemical process pipework and fired heater and reformer coils. In short: workhorse boiler pipe.
What is the yield strength of A335 P22 Q&T?
A335 P22 Q&T has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 63% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A335 P22 Q&T easy to machine?
Not especially — machinability is rated fair (44/100, worse than 71% of steel grades). Annealed P22 cuts much like annealed 4140, about 55–60 % of AISI 1212; use coated carbide at moderate speed with a healthy feed, and watch for work hardening and built-up edge at depth.
Can A335 P22 Q&T be welded?
With care — weldability is rated fair (50/100). Weld by GTAW or SMAW with matching Cr-Mo consumables (ER90S-B3, E9015-B3); preheat 200–250 °C, hold interpass below 350 °C, and apply 700–760 °C post-weld hydrogen-release and stress-relief heat treatment to prevent hydrogen cracking and a hard, brittle HAZ.
What surface finishes work on A335 P22 Q&T?
Not anodizable; shot blast and apply high-temperature heat-resistant coating, aluminizing or diffusion coating, or zinc plating for low-temperature duty, to control atmospheric and flue-gas side oxidation.
Can A335 P22 Q&T be formed, bent or molded?
Prefer hot bending and forming at 900–1000 °C, then re-normalize and temper; cold bending requires large bend radii followed by a stress-relief cycle.
What is the maximum service temperature of A335 P22 Q&T?
A335 P22 Q&T is rated for continuous use to about 580°C (1,076 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in A335 P22 Q&T?
Yes — A335 P22 Q&T is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service — ASTM International (2023)
- ASME BPVC Section II Part D — Materials, Properties (Metric) — ASME (2023)
- GB/T 5310 (12Cr2MoG / 10CrMo910) — SAC (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- API RP 941 — Steels for Hydrogen Service at Elevated Temperatures — API (2016)
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.