Steel A536 80-55-06-SR (Stress relieved)
Heat-treated state
ASTM A536 80-55-06 · EN EN-GJS-500-7, GGG50 · JIS FCD500 · GB QT500-7
Pick when residual casting/welding stresses must be removed before precision machining, with almost no loss of strength.
Values for the SR condition
Other A536 80-55-06 tempers and conditions
A536 80-55-06 is listed in 5 conditions; see the grade overview at A536 80-55-06.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SRThis page Stress relieved | Pick when residual casting/welding stresses must be removed before precision machining, with almost no loss of strength. | 390 | 565 | 9 | 190 HB | 2.9 % IACS |
AS-CASTDefault ferritic-pearlitic matrix, no post-cast heat treatment | Standard supply condition for 80-55-06 castings: chemistry and cooling rate alone give the 552/379/6 property set. | 400 | 575 | 8 | 195 HB | 2.9 % IACS |
Induction hardened | For wear surfaces (gear teeth, ways, journals): pearlitic matrix transforms to martensite in a shallow case while the core stays tough. | 400 | 575 | 7 | 52 HRC | 2.9 % IACS |
Normalized and tempered | Use to homogenize a mixed matrix in heavy or variable-section castings and raise strength toward the upper end of the grade. | 460 | 680 | 4 | 22 HRC | 2.8 % IACS |
Quenched and tempered | Choose for gears, sprockets and highly loaded parts where a tempered-martensite matrix is needed; ductility drops sharply. | 620 | 850 | 3 | 30 HRC | 2.7 % IACS |
What is A536 80-55-06-SR?
A536 80-55-06-SR is A536 80-55-06 heat treated to SR — pick when residual casting/welding stresses must be removed before precision machining, with almost no loss of strength. A536 80-55-06-SR has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 565 MPa (81.9 ksi) — weaker than 64% of steel grades. Elongation at break is 9% and the elastic modulus is 169 GPa (24.5 Msi). A536 80-55-06-SR has a density of 7.1 g/cm³ (0.257 lb/in³), lighter than 99% of steel grades. It melts at 1,150°C (2,102 °F). AS-CAST is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Easy to machine — 72/100, better than 97% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited formability — 6/100, worse than 98% of steel grades
- Low stiffness — 169 GPa (24.5 Msi), worse than 97% of steel grades
- Low fracture toughness — 33 MPa·√m (30 ksi·√in), worse than 95% of steel grades
- Limited ductility — 9%, worse than 93% of steel grades
- Low electrical conductivity — 2.9 % IACS, worse than 93% of steel grades
A536 80-55-06-SR properties
Typical room-temperature values for A536 80-55-06-SR; 21 are specific to this condition. Other listed values are A536 80-55-06 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A536 80-55-06-SR has a density of 7.1 g/cm³ (0.257 lb/in³), lighter than 99% of steel grades. It melts at 1,150°C (2,102 °F).
Mechanical15
A536 80-55-06-SR has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 565 MPa (81.9 ksi) — weaker than 64% of steel grades. Elongation at break is 9% and the elastic modulus is 169 GPa (24.5 Msi).
Thermal6
A536 80-55-06-SR is rated for continuous service to 350°C (662 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 75% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A536 80-55-06-SR conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of A536 80-55-06-SR takes about 20 MJ of energy and emits 1.9 kg of CO₂ — less than 99% of steel grades. Typical recycled content is 90%.
Manufacturability7
A536 80-55-06-SR's machinability is very good (72/100, better than 97% of steel grades); weldability poor (32/100); formability not recommended (6/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A536 80-55-06-SR
Is A536 80-55-06 easy to machine?
Machines easily with carbide at high feed; graphite gives short chips, but hard carbide edges or chill in thin sections wreck tools — check hardness before finishing.
Can A536 80-55-06 be welded?
Poor weldability: preheat 300–350 °C, NiFe (ENiFe-CI) electrodes, short stringer beads with peening, then stress relieve to avoid a brittle white-iron HAZ.
Can A536 80-55-06 be formed, bent or molded?
Green-sand or shell mould casting with Mg treatment and late inoculation; feed heavy sections and control cooling rate to keep the matrix in the ferritic-pearlitic window.
What surface finishes work on A536 80-55-06?
Not anodizable; protect with shot blast + epoxy/zinc-rich primer, powder coat, phosphate, or hard chrome/nitride on bearing surfaces; polishing is limited by graphite pull-out.
A536 80-55-06 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 |
|---|---|---|
| CASTM A536 does not specify chemistry; typical foundry practice shown | 3.2 – 3.9 | 3.6 |
| Si | 2 – 3 | 2.5 |
| Mnhigher Mn promotes pearlite | 0.15 – 0.6 | 0.35 |
| P | ≤ 0.05 | 0.03 |
| Slow S required for nodulizing | ≤ 0.02 | 0.01 |
| Mgresidual nodulizer | 0.03 – 0.06 | 0.04 |
| Cupearlite stabilizer, optional | 0 – 0.8 | 0.4 |
| Nioptional | 0 – 0.5 | — |
| Fe | balance | — |
A536 80-55-06-SR — frequently asked
What is A536 80-55-06-SR used for?
A536 80-55-06-SR is typically used for crankshafts, pump bodies, pressure valves and gearbox cases. In short: workhorse ductile iron grade; balanced strength and ductility; good machinability at 195 HB.
What is the yield strength of A536 80-55-06-SR?
A536 80-55-06-SR has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 565 MPa (81.9 ksi) — weaker than 64% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A536 80-55-06-SR easy to machine?
Yes — machinability is rated very good (72/100, better than 97% of steel grades). Machines easily with carbide at high feed; graphite gives short chips, but hard carbide edges or chill in thin sections wreck tools — check hardness before finishing.
Can A536 80-55-06-SR be welded?
Not readily — weldability is rated poor (32/100). Poor weldability: preheat 300–350 °C, NiFe (ENiFe-CI) electrodes, short stringer beads with peening, then stress relieve to avoid a brittle white-iron HAZ.
What surface finishes work on A536 80-55-06-SR?
Not anodizable; protect with shot blast + epoxy/zinc-rich primer, powder coat, phosphate, or hard chrome/nitride on bearing surfaces; polishing is limited by graphite pull-out.
Can A536 80-55-06-SR be formed, bent or molded?
Green-sand or shell mould casting with Mg treatment and late inoculation; feed heavy sections and control cooling rate to keep the matrix in the ferritic-pearlitic window.
What is the maximum service temperature of A536 80-55-06-SR?
A536 80-55-06-SR is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A536 80-55-06 AS-CAST and A536 80-55-06-QT?
AS-CAST is the default condition — standard supply condition for 80-55-06 castings: chemistry and cooling rate alone give the 552/379/6 property set. QT: choose for gears, sprockets and highly loaded parts where a tempered-martensite matrix is needed; ductility drops sharply. Yield strength is 400 MPa in AS-CAST versus 620 MPa in QT.
Sources
- ASTM A536 Standard Specification for Ductile Iron Castings — ASTM International (2019)
- EN 1563 Founding — Spheroidal graphite cast irons (EN-GJS-500-7) — CEN (2018)
- GB/T 1348 (QT500-7) — SAC (2019)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels — ASM International (1990)
- Ductile Iron Data for Design Engineers — Ductile Iron Society / Rio Tinto Iron & Titanium (2013)
- Dura-Bar 80-55-06 continuous cast ductile iron — Dura-Bar (Charter Manufacturing) (2022)
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.