Steel A48 Class 30
ASTM A48 Class 30 · EN EN-GJL-200, GG20 · JIS FC200 · GB HT200
ASTM A48 Class 30 is a general-purpose flake-graphite gray cast iron (EN-GJL-200, FC200, HT200, GG20, 0.6020) and the baseline grade for uncritical castings.
Reference datasheet — A48 Class 30 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 CLASS30 condition
A48 Class 30 tempers and conditions
A48 Class 30 is supplied in 14 conditions, soft to hard. CLASS30 is the default FabDigit quotes; the values on this page are for it.
- CLASS20
- FERRITIZE-ANN
- CLASS25
- SR
- CLASS30
- FLAME-HARD
- CLASS225
- CLASS35
- CLASS40
- CLASS45
- CLASS325
- CLASS50
- CLASS55
- CLASS60
Compare all 14 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
as-cast, 20 ksi / 150 MPa minimum tensile | Softest, most machinable and most damping grade — pick for thin uncritical covers, weights and counterweights where strength is irrelevant. | 115 | 152 | 0.6 | 156 HB | 55 W/m·K |
Ferritizing annealed (~760–900 °C, softened for machining) | Full ferritizing anneal used when maximum machinability and minimum hardness are needed and strength can be sacrificed. | 120 | 180 | 0.8 | 150 HB | 2.4 % IACS |
as-cast, 25 ksi / 175 MPa minimum tensile | Light-duty castings needing a little more strength than Class 20 while keeping easy machining and high damping. | 130 | 179 | 0.6 | 174 HB | 52 W/m·K |
Stress relieved | Sub-critical stress relief for machine tool bases and precision housings to stabilise dimensions before final machining. | 148 | 215 | 0.5 | 183 HB | 2.2 % IACS |
CLASS30Default as-cast, 30 ksi / 200 MPa minimum tensile | The workhorse general-engineering gray iron: best balance of strength, machinability, damping and cost for housings, bases and pump bodies. | 150 | 214 | 0.6 | 210 HB | 50 W/m·K |
Flame/induction surface hardened (~50 HRC case) | Localised hardening of pearlitic gray iron ways, cams and liner bores for wear resistance with a tough machinable core. | 150 | 220 | 0.3 | 50 HRC | 2 % IACS |
Metric Class 225 | Metric-only intermediate class between 200 and 250 MPa, used when a drawing is written to SI tensile minima. | 165 | 235 | 0.6 | 205 HB | 49 W/m·K |
as-cast, 35 ksi / 250 MPa minimum tensile | Higher-strength pearlitic gray iron for pressure-tight bodies, gearboxes, cylinder blocks and machine slides. | 180 | 252 | 0.5 | 212 HB | 48 W/m·K |
as-cast, 40 ksi / 275 MPa minimum tensile | Common continuous-cast bar and heavy-duty casting grade — good wear surfaces, still readily machinable. | 200 | 293 | 0.5 | 21 HRC | 46 W/m·K |
as-cast, 45 ksi / 300 MPa minimum tensile | High-strength alloyed/inoculated gray iron for loaded machine structures, dies and hydraulic bodies. | 220 | 327 | 0.5 | 24 HRC | 44 W/m·K |
Metric Class 325 | Metric-only class between 300 and 350 MPa for SI-specified high-strength gray iron castings. | 235 | 340 | 0.5 | 25 HRC | 43 W/m·K |
as-cast, 50 ksi / 350 MPa minimum tensile | Alloyed pearlitic gray iron for diesel cylinder blocks/heads, heavy machine tool structures and wear parts. | 250 | 362 | 0.4 | 26 HRC | 42 W/m·K |
as-cast, 55 ksi / 375 MPa minimum tensile | Near-maximum-strength flake iron, only achievable with alloying and controlled section size; specify when ductile iron cannot be used. | 270 | 396 | 0.4 | 29 HRC | 40 W/m·K |
as-cast, 60 ksi / 400 MPa minimum tensile | Highest ASTM A48 class — hard, stiff, alloyed gray iron for high-load, high-wear castings; hardest to machine and most section-sensitive. | 290 | 431 | 0.4 | 32 HRC | 38 W/m·K |
What is A48 Class 30?
ASTM A48 Class 30 is a general-purpose flake-graphite gray cast iron (EN-GJL-200, FC200, HT200, GG20, 0.6020) and the baseline grade for uncritical castings. Engineers choose it for its machinability score of 85, high vibration damping, low cost and 50 W/m·K thermal conductivity in sand, shell and lost-foam castings. Typical values are 214 MPa tensile, 150 MPa yield, 0.6 % elongation, 210 HB, 100 GPa modulus, 7.15 g/cm³ density and 400 °C maximum service temperature. It is effectively non-ductile (formability score 5), poorly weldable (score 30) and has little corrosion resistance (score 15); step up to Class 35/G3500 for strength or to ductile iron where impact loading exists. A48 Class 30 has a density of 7.15 g/cm³ (0.258 lb/in³), lighter than 99% of steel grades. It melts at 1,150°C (2,102 °F). A48 Class 30 has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 214 MPa (31 ksi) — weaker than 100% of steel grades. Elongation at break is 0.6% and the elastic modulus is 100 GPa (14.5 Msi).
What is A48 Class 30 used for?
- machine tool bases
- pipe fittings
- housings
- counterweights
- manifolds
Advantages
- Low embodied carbon — 1.6 kg CO₂/kg, better than 100% of steel grades
- Easy to machine — 85/100, better than 98% of steel grades
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
Limitations
- Low strength — 150 MPa (21.8 ksi), worse than 100% of steel grades
- Low stiffness — 100 GPa (14.5 Msi), worse than 100% of steel grades
- Low fracture toughness — 13 MPa·√m (11.8 ksi·√in), worse than 100% of steel grades
- Limited ductility — 0.6%, worse than 99% of steel grades
- Limited formability — 5/100, worse than 99% of steel grades
A48 Class 30 properties
Typical room-temperature values for A48 Class 30-CLASS30; bars are the position among steel grades.
Physical3
A48 Class 30 has a density of 7.15 g/cm³ (0.258 lb/in³), lighter than 99% of steel grades. It melts at 1,150°C (2,102 °F).
Mechanical15
A48 Class 30 has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 214 MPa (31 ksi) — weaker than 100% of steel grades. Elongation at break is 0.6% and the elastic modulus is 100 GPa (14.5 Msi).
Thermal6
A48 Class 30 is rated for continuous service to 400°C (752 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 11 µm/m·K (6.11 µin/in·°F).
Electrical3
A48 Class 30 conducts electricity at 2.2 % IACS, worse than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of A48 Class 30 takes about 18 MJ of energy and emits 1.6 kg of CO₂ — less than 100% of steel grades. Typical recycled content is 90%.
Manufacturability8
A48 Class 30's machinability is excellent (85/100, better than 98% of steel grades); weldability poor (30/100); formability not recommended (5/100).
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. A48 Class 30 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A48 Class 30
Is A48 Class 30 easy to machine?
Excellent dry machining with carbide or ceramic tools — flake graphite breaks chips and lubricates; watch abrasive casting skin, chilled edges and free graphite dust extraction.
Can A48 Class 30 be welded?
Poor weldability: preheat 200–320 °C, use NiFe/Ni electrodes or braze-weld, peen and slow-cool to avoid martensite and cracking — repair only, not structural joining.
Can A48 Class 30 be formed, bent or molded?
Sand/shell/lost-foam casting only; near-zero cold formability, so plan generous fillets, uniform sections ≥5 mm and consider CE and inoculation for section size.
A48 Class 30 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 A48 specifies no chemistry — tensile strength governs | 3.1 – 3.6 | 3.3 |
| Sitypical foundry practice for Class 30 | 1.8 – 2.4 | 2.1 |
| Mn | 0.5 – 0.9 | 0.7 |
| P | ≤ 0.15 | 0.08 |
| S | ≤ 0.15 | 0.09 |
| Croptional, raises strength/pearlite content | ≤ 0.35 | 0.1 |
| Cuoptional strengthener from scrap charge | ≤ 0.5 | — |
| Fe | balance | — |
What surface finishes work on A48 Class 30?
Shot-blast then paint, phosphate-and-oil or E-coat; can be black-oxided, hard-chromed or electroless-nickel plated, but graphite flakes limit high-gloss polishing and can cause plating pinholes.
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
Equivalent designations
Standards and trade names that resolve to Steel A48 Class 30 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- EN-GJL-200GG200.60200.6015
- GB (China)
- HT200
- JIS
- FC200
How much does A48 Class 30 cost?
A48 Class 30 is a budget-cost steel ($), cheaper than about 90% 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.
A48 Class 30 — frequently asked
What is A48 Class 30 used for?
A48 Class 30 is typically used for machine tool bases, pipe fittings, housings, counterweights and manifolds. In short: best-machining cast iron; high vibration damping; lowest-cost iron casting.
What is the yield strength of A48 Class 30?
A48 Class 30 has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 214 MPa (31 ksi) — weaker than 100% of steel grades. Strength varies by condition: see the 14 listed tempers.
Is A48 Class 30 easy to machine?
Yes — machinability is rated excellent (85/100, better than 98% of steel grades). Excellent dry machining with carbide or ceramic tools — flake graphite breaks chips and lubricates; watch abrasive casting skin, chilled edges and free graphite dust extraction.
Can A48 Class 30 be welded?
Not readily — weldability is rated poor (30/100). Poor weldability: preheat 200–320 °C, use NiFe/Ni electrodes or braze-weld, peen and slow-cool to avoid martensite and cracking — repair only, not structural joining.
What surface finishes work on A48 Class 30?
Shot-blast then paint, phosphate-and-oil or E-coat; can be black-oxided, hard-chromed or electroless-nickel plated, but graphite flakes limit high-gloss polishing and can cause plating pinholes.
Can A48 Class 30 be formed, bent or molded?
Sand/shell/lost-foam casting only; near-zero cold formability, so plan generous fillets, uniform sections ≥5 mm and consider CE and inoculation for section size.
What is the maximum service temperature of A48 Class 30?
A48 Class 30 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 A48 Class 30 CLASS30 and A48 Class 30 CLASS60?
CLASS30 is the default condition — the workhorse general-engineering gray iron: best balance of strength, machinability, damping and cost for housings, bases and pump bodies. CLASS60: highest ASTM A48 class — hard, stiff, alloyed gray iron for high-load, high-wear castings; hardest to machine and most section-sensitive. Yield strength is 150 MPa in CLASS30 versus 290 MPa in CLASS60.
How much does A48 Class 30 cost?
A48 Class 30 is a budget-cost steel ($), cheaper than about 90% 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 A48/A48M — Standard Specification for Gray Iron Castings — ASTM International (2022)
- EN 1561 — Founding: Grey cast irons (EN-GJL-200) — CEN (2011)
- GB/T 9439 — (HT200) — SAC (2010)
- JIS G 5501 — Grey iron castings (FC200) — JISC (1995)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (Gray Iron) — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- Machinery's Handbook, machinability ratings for cast irons — Industrial Press (2020)
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.