Steel A220 M5003-OQT (Oil-quenched and tempered)
Heat-treated state
ASTM A220 M5003 · JIS FCMP · GB KTZ700-02
Pick when a uniform tempered-martensite matrix and tighter hardness control through the section are wanted for wear parts.
Values for the OQT condition
Other A220 M5003 tempers and conditions
A220 M5003 is listed in 3 conditions; see the grade overview at A220 M5003.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AQTDefault Malleableized, air-quenched and tempered | Standard commercial route for M5003 castings: air quench from the austenitizing hold, then temper to the 179–229 HB band. | 380 | 550 | 4 | 197 HB | — |
Induction hardened | Use when the M5003 core toughness is kept but a hard wear surface (cams, sprocket teeth, journals) is needed. | 380 | 550 | 3 | 52 HRC | 5.5 % IACS |
OQTThis page Oil-quenched and tempered | Pick when a uniform tempered-martensite matrix and tighter hardness control through the section are wanted for wear parts. | 400 | 570 | 3.5 | 15 HRC | 5.4 % IACS |
What is A220 M5003-OQT?
A220 M5003-OQT is A220 M5003 heat treated to OQT — pick when a uniform tempered-martensite matrix and tighter hardness control through the section are wanted for wear parts. A220 M5003-OQT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 60% of steel grades. Elongation at break is 3.5% and the elastic modulus is 172 GPa (24.9 Msi). A220 M5003-OQT has a density of 7.3 g/cm³ (0.264 lb/in³), lighter than 98% of steel grades. It melts at 1,120°C (2,048 °F). AQT is the default condition FabDigit quotes; OQT is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.7 kg CO₂/kg, better than 99% of steel grades
Limitations
- Limited ductility — 3.5%, worse than 98% of steel grades
- Low stiffness — 172 GPa (24.9 Msi), worse than 96% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- Low electrical conductivity — 5.4 % IACS, worse than 81% of steel grades
A220 M5003-OQT properties
Typical room-temperature values for A220 M5003-OQT; 23 are specific to this condition. Other listed values are A220 M5003 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A220 M5003-OQT has a density of 7.3 g/cm³ (0.264 lb/in³), lighter than 98% of steel grades. It melts at 1,120°C (2,048 °F).
Mechanical13
A220 M5003-OQT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 60% of steel grades. Elongation at break is 3.5% and the elastic modulus is 172 GPa (24.9 Msi).
Thermal6
A220 M5003-OQT is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A220 M5003-OQT conducts electricity at 5.4 % IACS, worse than 81% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of A220 M5003-OQT takes about 20 MJ of energy and emits 1.7 kg of CO₂ — less than 99% of steel grades. Typical recycled content is 90%.
Manufacturability7
A220 M5003-OQT's machinability is good (60/100, better than 83% of steel grades); weldability poor (20/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A220 M5003-OQT
Is A220 M5003 easy to machine?
Machines well with carbide or coated carbide at moderate speeds; temper-carbon nodules break chips, but the pearlitic matrix is harder and more abrasive than ferritic malleable — expect ~80 % of AISI 1212 and check for any residual white-iron corners.
Can A220 M5003 be welded?
Poor fusion weldability: preheat 300–400 °C, Ni or NiFe filler, slow cool and re-temper; braze welding or mechanical joining is preferred for production parts.
Can A220 M5003 be formed, bent or molded?
Cast to shape as white iron in green sand/shell moulds with section thickness kept below roughly 25 mm, then malleableized (graphitizing anneal) and quench-tempered; only minor cold straightening/bending of thin lugs is possible.
What surface finishes work on A220 M5003?
Not anodizable; shot blast then paint, phosphate + oil, zinc plate or hot-dip galvanize for corrosion protection; surfaces can be induction hardened for wear.
A220 M5003 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; ASTM A220 controls properties, not chemistry — values are foundry-typical | 2 – 2.9 | 2.45 |
| Si | 0.9 – 1.9 | 1.4 |
| Mnraised in pearlitic grades to stabilize combined carbon | 0.25 – 1.25 | 0.6 |
| S | 0.03 – 0.18 | 0.1 |
| P | ≤ 0.15 | 0.05 |
| Crkept low to avoid stable carbides | ≤ 0.1 | 0.04 |
| Cuoptional pearlite/strength enhancer | ≤ 1 | — |
| Mooptional in heavier sections | ≤ 0.5 | — |
| Fe | balance | — |
A220 M5003-OQT — frequently asked
What is A220 M5003-OQT used for?
A220 M5003-OQT is typically used for gears, connecting rods, camshafts and universal joint yokes. In short: strongest malleable iron grade; wear-resistant pearlitic matrix; induction-hardenable surfaces.
What is the yield strength of A220 M5003-OQT?
A220 M5003-OQT has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is A220 M5003-OQT easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines well with carbide or coated carbide at moderate speeds; temper-carbon nodules break chips, but the pearlitic matrix is harder and more abrasive than ferritic malleable — expect ~80 % of AISI 1212 and check for any residual white-iron corners.
Can A220 M5003-OQT be welded?
Not readily — weldability is rated poor (20/100). Poor fusion weldability: preheat 300–400 °C, Ni or NiFe filler, slow cool and re-temper; braze welding or mechanical joining is preferred for production parts.
What surface finishes work on A220 M5003-OQT?
Not anodizable; shot blast then paint, phosphate + oil, zinc plate or hot-dip galvanize for corrosion protection; surfaces can be induction hardened for wear.
Can A220 M5003-OQT be formed, bent or molded?
Cast to shape as white iron in green sand/shell moulds with section thickness kept below roughly 25 mm, then malleableized (graphitizing anneal) and quench-tempered; only minor cold straightening/bending of thin lugs is possible.
What is the maximum service temperature of A220 M5003-OQT?
A220 M5003-OQT 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 M5003-AQT and A220 M5003-OQT?
AQT is the default condition — standard commercial route for M5003 castings: air quench from the austenitizing hold, then temper to the 179–229 HB band. OQT: pick when a uniform tempered-martensite matrix and tighter hardness control through the section are wanted for wear parts. Yield strength is 380 MPa in AQT versus 400 MPa in OQT.
Sources
- ASTM A220/A220M — Standard Specification for Pearlitic Malleable Iron — ASTM International (2018)
- GB/T 9440 (KTZ pearlitic malleable iron) (2010)
- JIS G 5705 Malleable iron castings (FCMP) — JSA (2000)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (Malleable Iron) — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
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.