Steel SS400 · supply condition · default condition
Steel SS400-HR
Properties of the HR condition, compared with the other SS400 tempers.
Default stock condition for plate, bar, angle and structural sections; cheapest, mill-scale surface, dimensional tolerances loose.
What is SS400-HR?
SS400-HR is SS400 supplied in the HR condition — default stock condition for plate, bar, angle and structural sections; cheapest, mill-scale surface, dimensional tolerances loose. SS400-HR has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 90% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi). SS400-HR 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).
Advantages
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Easy to machine — 65/100, better than 93% of steel grades
- Readily welded — 92/100, better than 93% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- Forms and bends easily — 78/100, better than 91% of steel grades
Limitations
- Low strength — 280 MPa (40.6 ksi), worse than 90% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
SS400-HR properties
Typical room-temperature values for SS400-HR — 12 properties are specific to this condition; the rest are grade-level values shared by every SS400 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
SS400-HR 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-HR has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 90% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SS400-HR is rated for continuous service to 350°C (662 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
SS400-HR conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of SS400-HR 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-HR's machinability is good (65/100, better than 93% of steel grades); weldability excellent (92/100); formability very good (78/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other SS400 tempers and conditions
SS400 is also supplied in 4 other conditions. The full side-by-side table is on the SS400 overview.
- HRDefaultDefault stock condition for plate, bar, angle and structural sections; cheapest, mill-scale surface, dimensional tolerances loose.280 MPa yield · 125 HB
- CRPick when a bright scale-free surface, tight thickness/diameter tolerance and higher yield are needed; ductility and bendability are reduced.380 MPa yield · 150 HB
- GalvanizedChoose for outdoor or damp-service parts that will not be painted; the zinc layer gives sacrificial protection but complicates welding and tight-radius forming.300 MPa yield · 130 HB
- NormalizedOccasionally ordered for thick plate or after heavy forming/flame cutting to refine grain and even out toughness; strength stays in the SS400 band.270 MPa yield · 120 HB
Working with SS400-HR
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-HR — frequently asked
What is SS400-HR used for?
SS400-HR is typically used for welded structures, bridges and building frames. In short: workhorse Japanese mild plate.
What is the yield strength of SS400-HR?
SS400-HR has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 90% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is SS400-HR easy to machine?
Reasonably — machinability is rated good (65/100, better than 93% 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-HR be welded?
Yes — weldability is rated excellent (92/100). 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-HR?
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-HR 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-HR?
SS400-HR 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-HR?
Yes — SS400-HR 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.