Steel SS400 Annealed
Temper
JIS SS400
Used for deep-drawn or severely bent parts and for stress relief of weldments; lowest hardness, poorest surface-finish machining behaviour.
Values for the Annealed condition
Other SS400 tempers and conditions
SS400 is listed in 4 conditions; see the grade overview at SS400.
- Annealed
- Normalized
- HR
- CR
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedThis page subcritical/full anneal for maximum ductility | Used for deep-drawn or severely bent parts and for stress relief of weldments; lowest hardness, poorest surface-finish machining behaviour. | 250 | 420 | 33 | 110 HB | 11 % IACS |
880–920 °C air cool (grain refinement of thick plate) | Occasionally ordered for thick plate or after heavy forming/flame cutting to refine grain and even out toughness; strength stays in the SS400 band. | 270 | 440 | 30 | 120 HB | 10.8 % IACS |
HRDefault Hot rolled | Default stock condition for plate, bar, angle and structural sections; cheapest, mill-scale surface, dimensional tolerances loose. | 280 | 450 | 26 | 125 HB | — |
Cold rolled | Pick when a bright scale-free surface, tight thickness/diameter tolerance and higher yield are needed; ductility and bendability are reduced. | 380 | 500 | 16 | 150 HB | — |
What is SS400 Annealed?
SS400 Annealed is SS400 in the Annealed temper — used for deep-drawn or severely bent parts and for stress relief of weldments; lowest hardness, poorest surface-finish machining behaviour. SS400 Annealed has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 94% of steel grades. Elongation at break is 33% and the elastic modulus is 205 GPa (29.7 Msi). SS400 Annealed 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). HR is the default condition FabDigit quotes; Annealed is available on request or by drawing note.
Advantages
- Conducts heat well — 52 W/m·K (30 BTU/hr·ft·°F), better than 98% of steel grades
- High electrical conductivity — 11 % IACS, better than 98% of steel grades
- Forms and bends easily — 88/100, better than 98% of steel grades
- Ductile — tolerates forming and impact — 33%, better than 96% of steel grades
- Readily welded — 93/100, better than 95% of steel grades
Limitations
- Low strength — 250 MPa (36.3 ksi), worse than 94% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
SS400 Annealed properties
Typical room-temperature values for SS400 Annealed; 22 are specific to this condition. Other listed values are SS400 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SS400 Annealed 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
SS400 Annealed has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 94% of steel grades. Elongation at break is 33% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SS400 Annealed is rated for continuous service to 350°C (662 °F). It conducts heat at 52 W/m·K (30 BTU/hr·ft·°F), better than 98% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
SS400 Annealed conducts electricity at 11 % IACS, better than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of SS400 Annealed takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
SS400 Annealed's machinability is good (58/100, better than 75% of steel grades); weldability excellent (93/100); formability excellent (88/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SS400 Annealed
Is SS400 easy to machine?
Cuts easily but gummy: use sharp positive-rake tooling, 100–200 m/min carbide, generous coolant and chip breakers to avoid built-up edge and stringy chips.
Can SS400 be welded?
Excellent weldability by SMAW/GMAW/FCAW/SAW with E7018 or ER70S-6; no preheat needed below roughly 25 mm section at room temperature — strip zinc back on galvanized stock and ventilate.
Can SS400 be formed, bent or molded?
Hot-rolled sheet bends readily to ~1.5×t inside radius (2–3×t for cold-rolled or galvanized); roll, press-brake and stamp cold, hot-form above 900 °C for heavy sections.
What surface finishes work on SS400?
Not anodizable — remove mill scale by shot blast or pickling, then paint, phosphate+oil, zinc plate, hot-dip galvanize or powder coat; bare steel rusts within days indoors if humid.
SS400 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 by JIS G3101 for SS400; mills typically 0.10–0.25 % | ≈ 0.17 | 0.17 |
| Sinot specified; typically ≤0.35 % | ≈ 0.2 | 0.2 |
| Mnnot specified; typically 0.30–0.80 % | ≈ 0.55 | 0.55 |
| PJIS G3101 limit (0.050 max) | ≤ 0.05 | 0.02 |
| SJIS G3101 limit (0.050 max) | ≤ 0.05 | 0.02 |
| Fe | balance | — |
SS400 Annealed — frequently asked
What is SS400 Annealed used for?
SS400 Annealed is typically used for welded structures, bridges and building frames. In short: workhorse Japanese mild plate.
What is the yield strength of SS400 Annealed?
SS400 Annealed has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 94% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SS400 Annealed easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Cuts easily but gummy: use sharp positive-rake tooling, 100–200 m/min carbide, generous coolant and chip breakers to avoid built-up edge and stringy chips.
Can SS400 Annealed be welded?
Yes — weldability is rated excellent (93/100). Excellent weldability by SMAW/GMAW/FCAW/SAW with E7018 or ER70S-6; no preheat needed below roughly 25 mm section at room temperature — strip zinc back on galvanized stock and ventilate.
What surface finishes work on SS400 Annealed?
Not anodizable — remove mill scale by shot blast or pickling, then paint, phosphate+oil, zinc plate, hot-dip galvanize or powder coat; bare steel rusts within days indoors if humid.
Can SS400 Annealed be formed, bent or molded?
Hot-rolled sheet bends readily to ~1.5×t inside radius (2–3×t for cold-rolled or galvanized); roll, press-brake and stamp cold, hot-form above 900 °C for heavy sections.
What is the maximum service temperature of SS400 Annealed?
SS400 Annealed is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SS400-HR and SS400-CR?
HR is the default condition — default stock condition for plate, bar, angle and structural sections; cheapest, mill-scale surface, dimensional tolerances loose. CR: pick when a bright scale-free surface, tight thickness/diameter tolerance and higher yield are needed; ductility and bendability are reduced. Yield strength is 280 MPa in HR versus 380 MPa in CR.
Can FabDigit make parts in SS400 Annealed?
Yes — SS400 Annealed is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- JIS G3101 — Rolled steels for general structure — Japanese Standards Association (2020)
- GB/T 700 — Carbon structural steels (Q235B comparison) — SAC (2006)
- ASTM A36/A36M — Carbon structural steel — ASTM (2019)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, 31st ed. (machinability ratings) — Industrial Press (2020)
- worldsteel LCI data for hot-rolled coil and plate — World Steel Association (2022)
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.