Steel A220 45008-AQT
Heat-treated state · default condition
ASTM A220 45008 · GB KTZ450-06
AQT = graphitized, air quenched and tempered
Default condition: parts are air-quenched from the austenitizing/graphitizing cycle and tempered to hit 45008 property window — best cost/strength balance for automotive and machinery castings.
Values for the AQT condition
Other A220 45008 tempers and conditions
A220 45008 is listed in 3 conditions; see the grade overview at A220 45008.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AQTDefaultThis page Graphitized, air quenched and tempered | Default condition: parts are air-quenched from the austenitizing/graphitizing cycle and tempered to hit 45008 property window — best cost/strength balance for automotive and machinery castings. | 330 | 470 | 10 | 175 HB | 4.7 % IACS |
Induction hardened | Use when wear surfaces (gear teeth, cam faces, bearing journals) need a hard case while the body keeps 45008 strength and ductility; the pearlitic matrix responds well to local hardening. | 330 | 470 | 9 | 55 HRC | 4.7 % IACS |
Oil quenched and tempered to grade 45008 properties | Pick for heavier sections or where a fully tempered martensitic/sorbitic matrix is wanted: slightly higher toughness and more uniform hardness through the wall than air quenching, at higher processing cost and distortion risk. | 345 | 500 | 11 | 183 HB | 4.6 % IACS |
What is A220 45008-AQT?
A220 45008-AQT is A220 45008 heat treated to AQT — default condition: parts are air-quenched from the austenitizing/graphitizing cycle and tempered to hit 45008 property window — best cost/strength balance for automotive and machinery castings. A220 45008-AQT has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 78% of steel grades. Elongation at break is 10% and the elastic modulus is 172 GPa (24.9 Msi). A220 45008-AQT has a density of 7.27 g/cm³ (0.263 lb/in³), lighter than 99% of steel grades. It melts at 1,135°C (2,075 °F).
Advantages
- Low embodied carbon — 1.8 kg CO₂/kg, better than 99% of steel grades
Limitations
- Low stiffness — 172 GPa (24.9 Msi), worse than 96% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
- Low electrical conductivity — 4.7 % IACS, worse than 82% of steel grades
A220 45008-AQT properties
Typical room-temperature values for A220 45008-AQT; 22 are specific to this condition. Other listed values are A220 45008 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A220 45008-AQT has a density of 7.27 g/cm³ (0.263 lb/in³), lighter than 99% of steel grades. It melts at 1,135°C (2,075 °F).
Mechanical16
A220 45008-AQT has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 78% of steel grades. Elongation at break is 10% and the elastic modulus is 172 GPa (24.9 Msi).
Thermal6
A220 45008-AQT is rated for continuous service to 400°C (752 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A220 45008-AQT conducts electricity at 4.7 % IACS, worse than 82% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of A220 45008-AQT takes about 20 MJ of energy and emits 1.8 kg of CO₂ — less than 99% of steel grades. Typical recycled content is 90%.
Manufacturability7
A220 45008-AQT's machinability is good (58/100, better than 75% of steel grades); weldability poor (25/100); formability poor (15/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A220 45008-AQT
Is A220 45008 easy to machine?
Machines like a medium-carbon steel but freer-cutting thanks to temper-carbon nodules; use carbide or coated carbide at moderate speeds, and machine before any selective surface hardening.
Can A220 45008 be welded?
Poor fusion weldability — preheat 300–400 °C, use Ni or NiFe electrodes/braze welding and slow cool, then re-temper; avoid welded joints in load paths where possible.
Can A220 45008 be formed, bent or molded?
Cast as thin-wall white iron in green sand or shell molds (heavy sections resist graphitization), then long graphitizing anneal followed by air/oil quench and temper; limited cold coining and straightening only.
What surface finishes work on A220 45008?
Shot blast to remove anneal scale; protect with paint, phosphate+oil, zinc plating or hot-dip galvanizing (classic for malleable fittings); accepts nitriding/hard chrome for wear duty.
A220 45008 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 |
|---|---|---|
| Ctotal carbon of white-iron base; converts to temper carbon on annealing | 2.2 – 2.9 | 2.5 |
| Si | 0.9 – 1.9 | 1.4 |
| Mnkept higher than ferritic malleable to stabilize pearlite | 0.25 – 1.25 | 0.6 |
| P | ≤ 0.18 | 0.08 |
| S | 0.05 – 0.2 | 0.12 |
| Crheld low to avoid stable carbides | ≤ 0.1 | 0.04 |
| FeASTM A220 does not fix chemistry; composition is at the foundry's option provided mechanical and hardness requirements are met | balance | — |
A220 45008-AQT — frequently asked
What is A220 45008-AQT used for?
A220 45008-AQT is typically used for gears, connecting rods, camshafts and high-strength fittings. In short: stronger than ferritic malleable; free-cutting at 175 HB; surface-hardenable wear parts.
What is the yield strength of A220 45008-AQT?
A220 45008-AQT has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 78% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is A220 45008-AQT easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a medium-carbon steel but freer-cutting thanks to temper-carbon nodules; use carbide or coated carbide at moderate speeds, and machine before any selective surface hardening.
Can A220 45008-AQT be welded?
Not readily — weldability is rated poor (25/100). Poor fusion weldability — preheat 300–400 °C, use Ni or NiFe electrodes/braze welding and slow cool, then re-temper; avoid welded joints in load paths where possible.
What surface finishes work on A220 45008-AQT?
Shot blast to remove anneal scale; protect with paint, phosphate+oil, zinc plating or hot-dip galvanizing (classic for malleable fittings); accepts nitriding/hard chrome for wear duty.
Can A220 45008-AQT be formed, bent or molded?
Cast as thin-wall white iron in green sand or shell molds (heavy sections resist graphitization), then long graphitizing anneal followed by air/oil quench and temper; limited cold coining and straightening only.
What is the maximum service temperature of A220 45008-AQT?
A220 45008-AQT is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A220 45008-AQT and A220 45008-OQT?
AQT is the default condition — default condition: parts are air-quenched from the austenitizing/graphitizing cycle and tempered to hit 45008 property window — best cost/strength balance for automotive and machinery castings. OQT: pick for heavier sections or where a fully tempered martensitic/sorbitic matrix is wanted: slightly higher toughness and more uniform hardness through the wall than air quenching, at higher processing cost and distortion risk. Yield strength is 330 MPa in AQT versus 345 MPa in OQT.
Sources
- ASTM A220/A220M — Standard Specification for Pearlitic Malleable Iron — ASTM International (2018)
- GB/T 9440 (KTZ450-06) (2010)
- JIS G 5705 Malleable iron castings (FCMP450) — JISC (2018)
- ASM Handbook Vol. 1: Properties and Selection — Malleable Iron — ASM International (1990)
- ASM Handbook Vol. 16: Machining — Machinability of Cast Irons — ASM International (1989)
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.