Steel SPHC · supply condition · default condition
Steel SPHC-HR
Properties of the HR condition, compared with the other SPHC tempers.
Default and cheapest form: structural brackets, weldments, tube stock where surface finish and tight tolerance are unimportant.
What is SPHC-HR?
SPHC-HR is SPHC supplied in the HR condition — default and cheapest form: structural brackets, weldments, tube stock where surface finish and tight tolerance are unimportant. SPHC-HR has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 96% of steel grades. Elongation at break is 38% and the elastic modulus is 205 GPa (29.7 Msi). SPHC-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F).
Advantages
- Ductile — tolerates forming and impact — 38%, better than 98% of steel grades
- Conducts heat well — 52 W/m·K (30 BTU/hr·ft·°F), better than 98% of steel grades
- Readily welded — 95/100, better than 97% of steel grades
- Easy to machine — 68/100, better than 95% of steel grades
- Forms and bends easily — 80/100, better than 92% of steel grades
Limitations
- Low strength — 240 MPa (34.8 ksi), worse than 96% of steel grades
- Hard to polish — 40/100, worse than 96% of steel grades
SPHC-HR properties
Typical room-temperature values for SPHC-HR — 10 properties are specific to this condition; the rest are grade-level values shared by every SPHC temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
SPHC-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F).
Mechanical15
SPHC-HR has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 96% of steel grades. Elongation at break is 38% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SPHC-HR is rated for continuous service to 400°C (752 °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
SPHC-HR conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of SPHC-HR takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
SPHC-HR's machinability is good (68/100, better than 95% of steel grades); weldability excellent (95/100); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other SPHC tempers and conditions
SPHC is also supplied in 3 other conditions. The full side-by-side table is on the SPHC overview.
- HRDefaultDefault and cheapest form: structural brackets, weldments, tube stock where surface finish and tight tolerance are unimportant.240 MPa yield · 110 HB
- GalvanizedChoose for outdoor or humid service without painting; zinc gives sacrificial protection but limits welding quality and service temperature.240 MPa yield · 110 HB
- CRChoose for thin gauges, bright smooth surface and tight thickness tolerance in stampings and enclosures (commercially supplied as SPCC-equivalent).215 MPa yield · 105 HB
Working with SPHC-HR
Is SPHC easy to machine?
Free-machining it is not — soft and gummy, so use positive rake, sharp tools, high feed and coolant to avoid built-up edge and burrs; ~68 % of AISI 1212.
Can SPHC be welded?
Excellent for MIG/TIG/spot/resistance welding with ER70S-6 and no preheat; on galvanized material remove or fume-extract the zinc coating.
Can SPHC be formed, bent or molded?
Good cold bending and stamping (bend radius ≈ 1×t for HR, tighter for pickled/CR); allow for coil-to-coil property scatter and mill scale cracking on tight bends.
What surface finishes work on SPHC?
Descale/pickle then phosphate + powder coat, e-coat, paint or zinc/zinc-nickel plate; bare surfaces flash-rust within days and need oiling.
SPHC 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 |
|---|---|---|
| CJIS G3131 SPHC | ≤ 0.15 | 0.08 |
| Mn | ≤ 0.6 | 0.35 |
| P | ≤ 0.05 | 0.02 |
| S | ≤ 0.05 | 0.02 |
| Sinot specified in JIS; typical Al-killed/rimmed practice | ≤ 0.05 | 0.02 |
| Fe | balance | — |
SPHC-HR — frequently asked
What is SPHC-HR used for?
SPHC-HR is typically used for welded frames, heavy equipment panels, brackets and gussets, structural tube and pipe stock, base and mounting plates and chassis members. In short: standard hot-rolled structural.
What is the yield strength of SPHC-HR?
SPHC-HR has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 96% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SPHC-HR easy to machine?
Reasonably — machinability is rated good (68/100, better than 95% of steel grades). Free-machining it is not — soft and gummy, so use positive rake, sharp tools, high feed and coolant to avoid built-up edge and burrs; ~68 % of AISI 1212.
Can SPHC-HR be welded?
Yes — weldability is rated excellent (95/100). Excellent for MIG/TIG/spot/resistance welding with ER70S-6 and no preheat; on galvanized material remove or fume-extract the zinc coating.
What surface finishes work on SPHC-HR?
Descale/pickle then phosphate + powder coat, e-coat, paint or zinc/zinc-nickel plate; bare surfaces flash-rust within days and need oiling.
Can SPHC-HR be formed, bent or molded?
Good cold bending and stamping (bend radius ≈ 1×t for HR, tighter for pickled/CR); allow for coil-to-coil property scatter and mill scale cracking on tight bends.
What is the maximum service temperature of SPHC-HR?
SPHC-HR 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 SPHC-HR and SPHC-CR?
HR is the default condition — default and cheapest form: structural brackets, weldments, tube stock where surface finish and tight tolerance are unimportant. CR: choose for thin gauges, bright smooth surface and tight thickness tolerance in stampings and enclosures (commercially supplied as SPCC-equivalent). Yield strength is 240 MPa in HR versus 215 MPa in CR.
Can FabDigit make parts in SPHC-HR?
Yes — SPHC-HR is available for sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- JIS G 3131 — Hot-rolled mild steel plates, sheets and strip — JISC (2018)
- JIS G 3141 — Cold-reduced carbon steel sheets and strip (SPCC) — JISC (2021)
- JIS G 3302 — Hot-dip zinc-coated steel sheets and coils — JISC (2019)
- GB/T 912 / GB/T 3274 — Hot-rolled carbon structural steel sheet and coil — SAC (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Machinery's Handbook (machinability ratings) — Industrial Press (2020)
- worldsteel LCI data for hot-rolled coil — World Steel Association (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.