Steel A842 Grade 450-N (Normalized)
Heat-treated state
ASTM A842 Grade 450 · EN EN-GJV-450 · GB RuT450 · ISO 16112 JV/450
Used when as-cast section size gives too much free ferrite; normalizing restores/raises pearlite content, strength and hardness at the cost of a little ductility and thermal conductivity.
Values for the N condition
Other A842 Grade 450 tempers and conditions
A842 Grade 450 is listed in 4 conditions; see the grade overview at A842 Grade 450.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress relieved | Pick for large or dimensionally critical castings (engine blocks, machine bases) to remove casting residual stress before finish machining, with only a small strength loss. | 340 | 470 | 1.8 | 20 HRC | 2.2 % IACS |
AS-CASTDefault pearlitic, no heat treatment (ASTM A842 requires Grade 450 as-cast) | Standard supply condition for Grade 450; alloying (Cu/Sn/Mn) gives a ~100 % pearlitic matrix straight from the mold. | 350 | 490 | 1.5 | 22 HRC | 2.2 % IACS |
Induction hardened | Choose when cylinder bores, seats or guideways need local wear resistance; the pearlitic matrix responds well to induction hardening while the bulk keeps as-cast properties. | 350 | 490 | 1.2 | 52 HRC | 2.2 % IACS |
NThis page Normalized | Used when as-cast section size gives too much free ferrite; normalizing restores/raises pearlite content, strength and hardness at the cost of a little ductility and thermal conductivity. | 390 | 530 | 1.2 | 25 HRC | 2.1 % IACS |
What is A842 Grade 450-N?
A842 Grade 450-N is A842 Grade 450 heat treated to N — used when as-cast section size gives too much free ferrite; normalizing restores/raises pearlite content, strength and hardness at the cost of a little ductility and thermal conductivity. A842 Grade 450-N has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 64% of steel grades. Elongation at break is 1.2% and the elastic modulus is 155 GPa (22.5 Msi). A842 Grade 450-N 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). AS-CAST is the default condition FabDigit quotes; N is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited formability — 2/100, worse than 100% of steel grades
- Limited ductility — 1.2%, worse than 99% of steel grades
- Low electrical conductivity — 2.1 % IACS, worse than 99% of steel grades
- Low fracture toughness — 23 MPa·√m (20.9 ksi·√in), worse than 98% of steel grades
- Low stiffness — 155 GPa (22.5 Msi), worse than 97% of steel grades
A842 Grade 450-N properties
Typical room-temperature values for A842 Grade 450-N; 21 are specific to this condition. Other listed values are A842 Grade 450 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A842 Grade 450-N 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).
Mechanical16
A842 Grade 450-N has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 64% of steel grades. Elongation at break is 1.2% and the elastic modulus is 155 GPa (22.5 Msi).
Thermal6
A842 Grade 450-N is rated for continuous service to 400°C (752 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A842 Grade 450-N conducts electricity at 2.1 % IACS, worse than 99% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of A842 Grade 450-N takes about 22 MJ of energy and emits 1.9 kg of CO₂ — less than 99% of steel grades. Typical recycled content is 90%.
Manufacturability7
A842 Grade 450-N's machinability is poor (30/100, worse than 89% of steel grades); weldability poor (20/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A842 Grade 450-N
Is A842 Grade 450 easy to machine?
Machinable but far more abrasive on tools than gray iron — use CBN/ceramic or coated carbide at reduced speed, avoid interrupted dry cuts, and expect the shortest tool life in continuous turning/boring.
Can A842 Grade 450 be welded?
Only repair welding: preheat 300–400 °C, NiFe or Ni electrodes, short stringer beads with peening and slow cooling to avoid a hard, cracked HAZ.
Can A842 Grade 450 be formed, bent or molded?
Green sand or shell molding with tight Mg/Ti and inoculation control (thermal analysis feedback); the compacted-graphite window is narrow so nodularity must be held below ~20 %.
What surface finishes work on A842 Grade 450?
No anodizing; protect with phosphate + oil, e-coat or paint. Nitriding and induction hardening work on the pearlitic matrix; polishing is limited by graphite pull-out.
A842 Grade 450 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 A842 does not fix composition; typical foundry practice | 3.1 – 3.9 | 3.6 |
| Si | 1.8 – 2.8 | 2.3 |
| Mnhigher end promotes pearlite for Grade 450 | 0.2 – 0.8 | 0.5 |
| Cupearlite stabilizer | 0.3 – 1 | 0.7 |
| Snoptional pearlite promoter | 0 – 0.1 | 0.04 |
| Mgresidual; narrow window controls compacted graphite | 0.01 – 0.03 | 0.01 |
| Tianti-nodularizer in some Ti-based processes | 0 – 0.05 | 0.01 |
| P | ≤ 0.06 | 0.03 |
| Smust be low before Mg treatment | ≤ 0.03 | 0.01 |
| Fe | balance | — |
A842 Grade 450-N — frequently asked
What is A842 Grade 450-N used for?
A842 Grade 450-N is typically used for diesel engine blocks, cylinder heads, exhaust manifolds and brake components. In short: between gray and ductile iron; high-output diesel block iron; shortest tool life in family.
What is the yield strength of A842 Grade 450-N?
A842 Grade 450-N has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 64% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A842 Grade 450-N easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Machinable but far more abrasive on tools than gray iron — use CBN/ceramic or coated carbide at reduced speed, avoid interrupted dry cuts, and expect the shortest tool life in continuous turning/boring.
Can A842 Grade 450-N be welded?
Not readily — weldability is rated poor (20/100). Only repair welding: preheat 300–400 °C, NiFe or Ni electrodes, short stringer beads with peening and slow cooling to avoid a hard, cracked HAZ.
What surface finishes work on A842 Grade 450-N?
No anodizing; protect with phosphate + oil, e-coat or paint. Nitriding and induction hardening work on the pearlitic matrix; polishing is limited by graphite pull-out.
Can A842 Grade 450-N be formed, bent or molded?
Green sand or shell molding with tight Mg/Ti and inoculation control (thermal analysis feedback); the compacted-graphite window is narrow so nodularity must be held below ~20 %.
What is the maximum service temperature of A842 Grade 450-N?
A842 Grade 450-N 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 A842 Grade 450 AS-CAST and A842 Grade 450-N?
AS-CAST is the default condition — standard supply condition for Grade 450; alloying (Cu/Sn/Mn) gives a ~100 % pearlitic matrix straight from the mold. N: used when as-cast section size gives too much free ferrite; normalizing restores/raises pearlite content, strength and hardness at the cost of a little ductility and thermal conductivity. Yield strength is 350 MPa in AS-CAST versus 390 MPa in N.
Sources
- ASTM A842-11 Standard Specification for Compacted Graphite Iron Castings — ASTM International (2011)
- EN 16112 Founding — Compacted (vermicular) graphite cast irons — CEN (2011)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Compacted Graphite Iron material data — SinterCast AB (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.