Steel SC450-SR (Stress relieved)
Heat-treated state
JIS G5101
Sub-critical treatment after welding or heavy machining to reduce distortion; mechanical properties stay close to the prior N/NT condition.
Values for the SR condition
Other SC450 tempers and conditions
SC450 is listed in 6 conditions; see the grade overview at SC450.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Choose when maximum machinability, dimensional stability and lowest residual stress matter more than strength. | 245 | 465 | 26 | 133 HB | — |
As fabricated | Only for non-critical castings; JIS G5101 normally requires heat treatment, so as-cast is used for rough or low-duty parts. | 250 | 480 | 18 | 150 HB | 10 % IACS |
SRThis page Stress relieved | Sub-critical treatment after welding or heavy machining to reduce distortion; mechanical properties stay close to the prior N/NT condition. | 270 | 485 | 25 | 140 HB | 10 % IACS |
NDefault Normalized | The standard stocked condition: refines the as-cast structure and gives the balanced 450 MPa-class strength/ductility JIS G5101 requires. | 275 | 495 | 24 | 145 HB | — |
Normalized and tempered | Pick for pressure-containing or welded castings where residual stress is relieved and impact toughness is more consistent. | 280 | 490 | 25 | 143 HB | — |
Quenched and tempered | Use when higher yield strength and better low-temperature toughness are needed from the same casting chemistry; limited by thin-section hardenability. | 410 | 590 | 21 | 12 HRC | — |
What is SC450-SR?
SC450-SR is SC450 heat treated to SR — sub-critical treatment after welding or heavy machining to reduce distortion; mechanical properties stay close to the prior N/NT condition. SC450-SR has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 485 MPa (70.3 ksi) — weaker than 91% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi). SC450-SR 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). N is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Easy to machine — 64/100, better than 92% of steel grades
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Low strength — 270 MPa (39.2 ksi), worse than 91% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
SC450-SR properties
Typical room-temperature values for SC450-SR; 22 are specific to this condition. Other listed values are SC450 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SC450-SR 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).
Mechanical16
SC450-SR has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 485 MPa (70.3 ksi) — weaker than 91% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SC450-SR is rated for continuous service to 425°C (797 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
SC450-SR conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SC450-SR takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 80%.
Manufacturability8
SC450-SR's machinability is good (64/100, better than 92% of steel grades); weldability very good (80/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SC450-SR
Is SC450 easy to machine?
Machines like normalized 1030–1035 steel at ~65 % of AISI 1212; watch for hard sand/scale skin and take a heavier first cut with coated carbide.
Can SC450 be welded?
Readily welded by SMAW/GMAW/FCAW with E7018-class filler; preheat 100–150 °C for sections over ~25 mm and stress relieve at 600–650 °C for pressure parts.
Can SC450 be formed, bent or molded?
Sand or shell mould casting with generous risering (steel shrinkage ~2 %); heat treat after casting to break up the coarse as-cast structure.
What surface finishes work on SC450?
No anodizing; shot blast then phosphate + paint, zinc-rich primer or hot-dip galvanize for outdoor service; hard chrome or nitriding possible on machined seats.
SC450 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 specified in JIS G5101; typical foundry aim for the 450 MPa class | ≤ 0.4 | 0.32 |
| SiTypical deoxidation practice, not a JIS limit | 0.2 – 0.6 | 0.4 |
| MnTypical foundry range, not a JIS limit | 0.5 – 1 | 0.75 |
| PJIS G5101 specified maximum | ≤ 0.04 | 0.02 |
| SJIS G5101 specified maximum | ≤ 0.04 | 0.02 |
| Fe | balance | — |
SC450-SR — frequently asked
What is SC450-SR used for?
SC450-SR is typically used for pump housings, valve bodies, gear blanks and structural machine parts. In short: JIS equivalent of WCB; balanced strength and weldability; general-purpose cast steel.
What is the yield strength of SC450-SR?
SC450-SR has a typical yield strength of 270 MPa (39.2 ksi) and a tensile strength of 485 MPa (70.3 ksi) — weaker than 91% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is SC450-SR easy to machine?
Reasonably — machinability is rated good (64/100, better than 92% of steel grades). Machines like normalized 1030–1035 steel at ~65 % of AISI 1212; watch for hard sand/scale skin and take a heavier first cut with coated carbide.
Can SC450-SR be welded?
Yes — weldability is rated very good (80/100). Readily welded by SMAW/GMAW/FCAW with E7018-class filler; preheat 100–150 °C for sections over ~25 mm and stress relieve at 600–650 °C for pressure parts.
What surface finishes work on SC450-SR?
No anodizing; shot blast then phosphate + paint, zinc-rich primer or hot-dip galvanize for outdoor service; hard chrome or nitriding possible on machined seats.
Can SC450-SR be formed, bent or molded?
Sand or shell mould casting with generous risering (steel shrinkage ~2 %); heat treat after casting to break up the coarse as-cast structure.
What is the maximum service temperature of SC450-SR?
SC450-SR 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 SC450-N and SC450-QT?
N is the default condition — the standard stocked condition: refines the as-cast structure and gives the balanced 450 MPa-class strength/ductility JIS G5101 requires. QT: use when higher yield strength and better low-temperature toughness are needed from the same casting chemistry; limited by thin-section hardenability. Yield strength is 275 MPa in N versus 410 MPa in QT.
Sources
- JIS G5101 Carbon steel castings — Japanese Standards Association (1991)
- ASTM A216/A216M (WCB, comparable grade) — ASTM International (2018)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol. 15 — Casting — ASM International (2008)
- Machinery's Handbook (machinability ratings) — Industrial Press (2020)
- GB/T 11352 ZG270-500 (equivalent Chinese cast carbon steel) — SAC (2009)
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.