Steel A148
ASTM A148
A general specification for carbon and low-alloy steel castings classified by tensile/yield strength grades (e.g., 80-40, 105-85, 150-125) rather than fixed chemistry, used where strength and toughness matter more than exact composition.
Reference datasheet — A148 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the 90-60 condition
A148 tempers and conditions
A148 is supplied in 12 conditions, soft to hard. 90-60 is the default FabDigit quotes; the values on this page are for it.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Grade 80-40 [550-275] | Lowest-strength A148 class; pick for large weldable structural castings where ductility and cost beat strength. | 320 | 585 | 24 | 150 HB | — |
Grade 80-50 [550-345] | Ductile general-purpose structural class with a higher yield floor than 80-40 at the same tensile level. | 385 | 585 | 24 | 160 HB | — |
90-60Default Grade 90-60 [620-415] | Most commonly ordered A148 class — good balance of strength, ductility and field weldability for general machinery castings. | 455 | 660 | 22 | 180 HB | — |
Grade 105-85 [725-585] | First clearly quench-and-tempered class; use for loaded gear blanks, links and housings needing ~585 MPa yield. | 620 | 760 | 19 | 18 HRC | 43 W/m·K |
Grade 115-95 [795-655] | Mid-strength Q&T class for mining, rail and construction castings carrying high static loads. | 690 | 830 | 16 | 22 HRC | 42 W/m·K |
Grade 130-115 [895-795] | High-strength Q&T low-alloy casting for crane hooks, dipper teeth and heavy-duty gearing. | 830 | 930 | 13 | 27 HRC | 41 W/m·K |
Grade 135-125 [930-860] | High yield-to-tensile class where design is yield-limited and section sizes must stay small. | 895 | 965 | 11 | 29 HRC | 41 W/m·K |
Grade 150-135 [1035-930] | Very high strength Q&T casting for compact, heavily loaded parts; ductility and weldability are limited. | 965 | 1,070 | 9 | 33 HRC | 40 W/m·K |
Grade 160-145 [1105-1000] | Near-top strength class; specify only with tight NDT because notch sensitivity is high. | 1,035 | 1,140 | 8 | 35 HRC | 40 W/m·K |
Grade 165-150 [1140-1035] | Ultra-high-strength structural casting class for hooks, sockets and rigging hardware; requires low-S/P clean steel. | 1,070 | 1,180 | 7 | 37 HRC | 39 W/m·K |
Grade 210-180 [1450-1240] | Special ultra-high-strength class for armor-like and highly loaded compact castings; very low ductility, welding normally prohibited. | 1,310 | 1,500 | 5 | 44 HRC | 38 W/m·K |
Grade 260-210 [1795-1450] | Maximum-strength A148 class; essentially a martensitic casting used only where extreme strength justifies near-zero ductility. | 1,520 | 1,830 | 4 | 51 HRC | 37 W/m·K |
What is A148?
A general specification for carbon and low-alloy steel castings classified by tensile/yield strength grades (e.g., 80-40, 105-85, 150-125) rather than fixed chemistry, used where strength and toughness matter more than exact composition. A148 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). A148 has a yield strength of 455 MPa (66 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 54% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
What is A148 used for?
- mining machinery frames
- construction equipment parts
- railway couplers
- crane hooks
- structural castings
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
A148 properties
Typical room-temperature values for A148-90-60; bars are the position among steel grades.
Physical3
A148 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
A148 has a yield strength of 455 MPa (66 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 54% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A148 is rated for continuous service to 425°C (797 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
A148 conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A148 takes about 27 MJ of energy and emits 2 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 85%.
Manufacturability8
A148's machinability is good (55/100, better than 62% of steel grades); weldability good (60/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. A148 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A148
Is A148 easy to machine?
Machine after heat treatment with rigid setups and carbide tooling; expect abrasive scale/sand at the as-cast skin — take a heavy first cut, and reduce speeds sharply above 300 HB.
Can A148 be welded?
Weldable in the lower classes (80-40 to 105-85) with low-hydrogen consumables, 150–260 °C preheat and post-weld stress relief; above ~130-115 obtain foundry approval and re-temper after welding.
Can A148 be formed, bent or molded?
Sand or shell cast with generous risering and chills — steel's ~2 % solidification shrinkage and low fluidity demand large gates, and all grades need normalizing or Q&T to break up the as-cast dendritic structure.
A148 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 |
|---|---|---|
| CNot fixed by A148 — chosen by the foundry; ≤0.30 % typical when weldability is required | 0.15 – 0.5 | 0.3 |
| Mnmanufacturer's option | 0.5 – 1.6 | 1 |
| Simanufacturer's option | 0.2 – 0.8 | 0.5 |
| PA148 maximum (0.04 max for higher-strength/weldable classes) | ≤ 0.05 | 0.02 |
| SA148 maximum (0.045 max for higher-strength/weldable classes) | ≤ 0.06 | 0.02 |
| Nioptional hardenability addition for 105-85 and stronger classes | 0 – 3.5 | 0.8 |
| Croptional | 0 – 1.5 | 0.6 |
| Mooptional; typical in Q&T classes | 0 – 0.6 | 0.25 |
| Voptional micro-alloy | 0 – 0.12 | 0.04 |
| Fe | balance | — |
What surface finishes work on A148?
No anodizing; shot blast then phosphate plus paint, zinc-rich primer, hot-dip galvanizing or hard chrome on machined bearing surfaces; avoid electroplating of high-strength classes without hydrogen bake-out.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
How much does A148 cost?
A148 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A148 — frequently asked
What is A148 used for?
A148 is typically used for mining machinery frames, construction equipment parts, railway couplers, crane hooks and structural castings. In short: strength-class cast steel spec; widest cast strength range; chemistry left to foundry.
What is the yield strength of A148?
A148 has a typical yield strength of 455 MPa (66 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 54% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is A148 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine after heat treatment with rigid setups and carbide tooling; expect abrasive scale/sand at the as-cast skin — take a heavy first cut, and reduce speeds sharply above 300 HB.
Can A148 be welded?
Yes — weldability is rated good (60/100). Weldable in the lower classes (80-40 to 105-85) with low-hydrogen consumables, 150–260 °C preheat and post-weld stress relief; above ~130-115 obtain foundry approval and re-temper after welding.
What surface finishes work on A148?
No anodizing; shot blast then phosphate plus paint, zinc-rich primer, hot-dip galvanizing or hard chrome on machined bearing surfaces; avoid electroplating of high-strength classes without hydrogen bake-out.
Can A148 be formed, bent or molded?
Sand or shell cast with generous risering and chills — steel's ~2 % solidification shrinkage and low fluidity demand large gates, and all grades need normalizing or Q&T to break up the as-cast dendritic structure.
What is the maximum service temperature of A148?
A148 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A148 90-60 and A148 260-210?
90-60 is the default condition — most commonly ordered A148 class — good balance of strength, ductility and field weldability for general machinery castings. 260-210: maximum-strength A148 class; essentially a martensitic casting used only where extreme strength justifies near-zero ductility. Yield strength is 455 MPa in 90-60 versus 1,520 MPa in 260-210.
How much does A148 cost?
A148 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A148/A148M Standard Specification for Steel Castings, High Strength, for Structural Purposes — ASTM International (2020)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys (Cast Steels) — ASM International (1990)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASTM A370 Standard Test Methods and Definitions for Mechanical Testing of Steel Products (hardness conversions) — ASTM International (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.