Steel A532 Class III Type A AC+SR
Heat-treated state
ASTM A532 Class III Type A · GB KmTBCr26
AC+SR = as-cast and stress-relieved
As-cast parts given a subcritical stress-relief to reduce casting-stress cracking in thick or complex sections.
Values for the AC+SR condition
Other A532 Class III Type A tempers and conditions
A532 Class III Type A is listed in 5 conditions; see the grade overview at A532 Class III Type A.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Softened (soft annealed) for machining, 400 HB max | Pick when the casting must be drilled, turned or bored before final hardening; wear resistance in this state is poor. | — | 420 | 0.5 | 41 HRC | — |
Spheroidize annealed | Lowest-cost condition; adequate for many liners and pump parts where as-cast 600 HB minimum is sufficient. | — | 480 | 0 | 60 HRC | — |
AC+SRThis page As-cast and stress-relieved | As-cast parts given a subcritical stress-relief to reduce casting-stress cracking in thick or complex sections. | — | 500 | 0 | 60 HRC | 1.7 % IACS |
HTDefault Hardened | Standard supply condition for demanding abrasion service — maximum matrix martensite and peak hardness (≥600 HB). | — | 550 | 0 | 64 HRC | — |
Hardened and stress-relieved | Choose for thick or impact-loaded wear parts: a subcritical temper trades a few HB for lower residual stress and better crack resistance. | — | 570 | 0 | 62 HRC | 1.9 % IACS |
What is A532 Class III Type A AC+SR?
A532 Class III Type A AC+SR is A532 Class III Type A heat treated to AC+SR — as-cast parts given a subcritical stress-relief to reduce casting-stress cracking in thick or complex sections. A532 Class III Type A AC+SR has a tensile strength of 500 MPa (72.5 ksi), weaker than 80% of steel grades. Elongation at break is 0% and the elastic modulus is 205 GPa (29.7 Msi). A532 Class III Type A AC+SR has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,230°C (2,246 °F). HT is the default condition FabDigit quotes; AC+SR is available on request or by drawing note.
Advantages
- Good corrosion resistance — 38/100, better than 97% of steel grades
- High service temperature — 450°C (842 °F), better than 86% of steel grades
Limitations
- Limited ductility — 0%, worse than 100% of steel grades
- Difficult to machine — 3/100, worse than 100% of steel grades
- Limited formability — 2/100, worse than 100% of steel grades
- Difficult to weld — 8/100, worse than 99% of steel grades
- Low fracture toughness — 24 MPa·√m (21.8 ksi·√in), worse than 98% of steel grades
A532 Class III Type A AC+SR properties
Typical room-temperature values for A532 Class III Type A AC+SR; 21 are specific to this condition. Other listed values are A532 Class III Type A reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A532 Class III Type A AC+SR has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 97% of steel grades. It melts at 1,230°C (2,246 °F).
Mechanical13
A532 Class III Type A AC+SR has a tensile strength of 500 MPa (72.5 ksi), weaker than 80% of steel grades. Elongation at break is 0% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A532 Class III Type A AC+SR is rated for continuous service to 450°C (842 °F). It conducts heat at 19 W/m·K (11 BTU/hr·ft·°F), worse than 97% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical2
A532 Class III Type A AC+SR has an electrical resistivity of 1×10⁻⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (38/100), better than 97% of steel grades.
Sustainability4
Producing a kilogram of A532 Class III Type A AC+SR takes about 28 MJ of energy and emits 2.4 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 65%.
Manufacturability8
A532 Class III Type A AC+SR's machinability is not recommended (3/100, worse than 100% of steel grades); weldability not recommended (8/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A532 Class III Type A AC+SR
Is A532 Class III Type A easy to machine?
In the hardened state only grinding, EDM or CBN/ceramic cutting is practical; do any drilling or turning in the softened (≤400 HB) condition and re-harden afterwards.
Can A532 Class III Type A be welded?
Not a weldable structural material — repair or hardfacing overlay only, with 250–400 °C preheat, austenitic Ni or high-Cr electrodes and slow cooling to limit cracking.
Can A532 Class III Type A be formed, bent or molded?
Sand/shell casting to near-net shape with generous feeders and controlled section change; no forging, rolling or cold forming is possible.
What surface finishes work on A532 Class III Type A?
Normally used bare as a wear face; surfaces are ground or shot-blasted, and non-wear faces can be painted for storage/transport corrosion protection.
A532 Class III Type A 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 | 2 – 3.3 | 2.8 |
| Mn | ≤ 2 | 0.8 |
| Si | ≤ 1.5 | 0.7 |
| Ni | ≤ 1.5 | 0.3 |
| Cr | 23 – 30 | 26 |
| Momax; added for hardenability in heavy sections | ≤ 3 | 1 |
| Cu | ≤ 1.2 | 0.3 |
| P | ≤ 0.1 | 0.04 |
| S | ≤ 0.06 | 0.03 |
| Fe | balance | — |
A532 Class III Type A AC+SR — frequently asked
What is A532 Class III Type A AC+SR used for?
A532 Class III Type A AC+SR is typically used for slurry pumps, mill liners, dredge pump parts and coal pulverizer components. In short: hardest white iron grade; abrasion plus mild corrosion; 600 °C wear service.
What is the tensile strength of A532 Class III Type A AC+SR?
A532 Class III Type A AC+SR has a typical tensile strength of 500 MPa (72.5 ksi) — weaker than 80% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A532 Class III Type A AC+SR easy to machine?
Not especially — machinability is rated not recommended (3/100, worse than 100% of steel grades). In the hardened state only grinding, EDM or CBN/ceramic cutting is practical; do any drilling or turning in the softened (≤400 HB) condition and re-harden afterwards.
Can A532 Class III Type A AC+SR be welded?
Not readily — weldability is rated not recommended (8/100). Not a weldable structural material — repair or hardfacing overlay only, with 250–400 °C preheat, austenitic Ni or high-Cr electrodes and slow cooling to limit cracking.
What surface finishes work on A532 Class III Type A AC+SR?
Normally used bare as a wear face; surfaces are ground or shot-blasted, and non-wear faces can be painted for storage/transport corrosion protection.
Can A532 Class III Type A AC+SR be formed, bent or molded?
Sand/shell casting to near-net shape with generous feeders and controlled section change; no forging, rolling or cold forming is possible.
What is the maximum service temperature of A532 Class III Type A AC+SR?
A532 Class III Type A AC+SR is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM A532/A532M Standard Specification for Abrasion-Resistant Cast Irons — ASTM International (2019)
- GB/T 8263 (KmTBCr26) — SAC (2010)
- EN 12513 Founding — Abrasion resistant cast irons (GX300CrMo15-3 / GX260Cr27) — CEN (2011)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Abrasion-Resistant Cast Irons) — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- High-chrome white iron wear casting datasheets (mill liners, slurry pump parts) — Various foundries (2023)
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.