Steel SECC-3
Supply condition
JIS SECC
SECC-3 = 1/4 hard, electro-galvanized
Quarter-hard sheet for flat covers and shear/roll-formed profiles needing more stiffness than standard temper.
Values for the SECC-3 condition
Other SECC tempers and conditions
SECC is listed in 10 conditions; see the grade overview at SECC.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed (soft) temper, electro-galvanized | Softest temper — pick for deep bends, hemming and severe forming where springback must be minimal. | 195 | 290 | 42 | 88 HB | 11 % IACS |
Cold rolled | Uncoated cold-rolled substrate condition — use when the part is painted/plated in-house and the mill zinc layer is not required. | 215 | 300 | 39 | 92 HB | 11 % IACS |
Standard temper, electro-galvanized | Mill standard skin-passed temper — the normal choice for bent chassis parts and painted panels. | 220 | 305 | 38 | 98 HB | 11 % IACS |
Electro-galvanized, no chromate passivation | Bare zinc surface with no passivation — used where the part is immediately painted, adhesive-bonded or must be Cr(VI)-free. | 220 | 305 | 38 | 98 HB | 11 % IACS |
Electro-galvanized with anti-fingerprint (organic/inorganic) top coat | Thin clear anti-fingerprint film over the zinc — used for unpainted visible IT/appliance chassis where handling marks and light humidity must be resisted. | 220 | 305 | 38 | 98 HB | 11 % IACS |
HRDefault Hot rolled | Choose hot-rolled stock when thickness and cost matter more than surface quality; tolerances and finish are coarser, with cold rolling or coating applied in later processing steps. | 240 | 340 | 36 | 105 HB | 11 % IACS |
1/8 hard (temper-rolled), electro-galvanized | Light temper rolling for flatter panels and slightly higher stiffness with moderate bending still possible. | 285 | 350 | 24 | 118 HB | 11 % IACS |
SECC-3This page 1/4 hard, electro-galvanized | Quarter-hard sheet for flat covers and shear/roll-formed profiles needing more stiffness than standard temper. | 340 | 395 | 17 | 133 HB | 11 % IACS |
1/2 hard, electro-galvanized | Half-hard sheet where flatness, dent resistance and higher yield matter and only gentle bends are needed. | 410 | 460 | 10 | 157 HB | 11 % IACS |
Full hard, electro-galvanized | Full-hard as-rolled temper — highest strength and flatness, essentially only for flat blanks, shearing and very light forming. | 540 | 570 | 3 | 185 HB | 11 % IACS |
What is SECC-3?
SECC-3 is SECC supplied in the SECC-3 condition — quarter-hard sheet for flat covers and shear/roll-formed profiles needing more stiffness than standard temper. SECC-3 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 76% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi). SECC-3 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F). HR is the default condition FabDigit quotes; SECC-3 is available on request or by drawing note.
Advantages
- High electrical conductivity — 11 % IACS, better than 98% of steel grades
- Easy to machine — 70/100, better than 96% of steel grades
- Good corrosion resistance — 30/100, better than 95% of steel grades
- Tough — resists crack growth — 140 MPa·√m (127.4 ksi·√in), better than 94% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
Limitations
- Hard to polish — 35/100, worse than 99% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
SECC-3 properties
Typical room-temperature values for SECC-3; 21 are specific to this condition. Other listed values are SECC reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SECC-3 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical16
SECC-3 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 76% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SECC-3 is rated for continuous service to 200°C (392 °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
SECC-3 conducts electricity at 11 % IACS, better than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of SECC-3 takes about 35 MJ of energy and emits 2.5 kg of CO₂ — more than 87% of steel grades. Typical recycled content is 25%.
Manufacturability7
SECC-3's machinability is very good (70/100, better than 96% of steel grades); weldability very good (76/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SECC-3
Is SECC easy to machine?
Soft and gummy — punch, laser or shear rather than mill; use sharp tools, high rake and light feeds to avoid burrs and zinc smearing, and expect coating loss on all cut edges.
Can SECC be welded?
Excellent resistance spot/projection welding (use ~10–20 % higher current and more frequent tip dressing than bare CR); MIG/TIG needs fume extraction and post-weld zinc-rich touch-up because zinc burns off in the heat-affected zone.
Can SECC be formed, bent or molded?
Very good cold formability in A/S tempers — bends to 1T–2T, deep drawing possible in the soft temper; the zinc layer acts as a mild lubricant but heavy draws can flake it, so galling and die pick-up should be checked.
What surface finishes work on SECC?
Take as-supplied chromate or anti-fingerprint finish for indoor use; phosphate grade or a light alkaline clean plus conversion coat for powder coating; touch up cut edges, welds and drilled holes with zinc-rich primer for humid service.
SECC 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 |
|---|---|---|
| CSPCC base per JIS G3141 | ≤ 0.15 | 0.06 |
| Mn | ≤ 0.6 | 0.3 |
| P | ≤ 0.1 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Zn coatingElectroplated zinc, ≥99 % Zn; typical coating mass 20/20 g/m² per side (≈2.8 µm), range 8–40 g/m² per JIS G3313 designations E8–E40 | — | — |
| Febase steel | balance | — |
SECC-3 — frequently asked
What is SECC-3 used for?
SECC-3 is typically used for industrial enclosures, computer and server chassis, electrical cabinets and panels, appliance side and back panels, mounting brackets and trays and rack-mount hardware. In short: electro-galvanized commercial coil.
What is the yield strength of SECC-3?
SECC-3 has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is SECC-3 easy to machine?
Yes — machinability is rated very good (70/100, better than 96% of steel grades). Soft and gummy — punch, laser or shear rather than mill; use sharp tools, high rake and light feeds to avoid burrs and zinc smearing, and expect coating loss on all cut edges.
Can SECC-3 be welded?
Yes — weldability is rated very good (76/100). Excellent resistance spot/projection welding (use ~10–20 % higher current and more frequent tip dressing than bare CR); MIG/TIG needs fume extraction and post-weld zinc-rich touch-up because zinc burns off in the heat-affected zone.
What surface finishes work on SECC-3?
Take as-supplied chromate or anti-fingerprint finish for indoor use; phosphate grade or a light alkaline clean plus conversion coat for powder coating; touch up cut edges, welds and drilled holes with zinc-rich primer for humid service.
Can SECC-3 be formed, bent or molded?
Very good cold formability in A/S tempers — bends to 1T–2T, deep drawing possible in the soft temper; the zinc layer acts as a mild lubricant but heavy draws can flake it, so galling and die pick-up should be checked.
What is the maximum service temperature of SECC-3?
SECC-3 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SECC-HR and SECC-1?
HR is the default condition — choose hot-rolled stock when thickness and cost matter more than surface quality; tolerances and finish are coarser, with cold rolling or coating applied in later processing steps. SECC-1: full-hard as-rolled temper — highest strength and flatness, essentially only for flat blanks, shearing and very light forming. Yield strength is 240 MPa in HR versus 540 MPa in SECC-1.
Can FabDigit make parts in SECC-3?
Yes — SECC-3 is available for sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- JIS G 3313 — Electrolytic zinc-coated steel sheet and strip — JSA (2021)
- JIS G 3141 — Cold-reduced carbon steel sheet and strip (SPCC base) — JSA (2021)
- GB/T 15675 / GB/T 5213 equivalents for — SAC (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials (zinc coatings) — ASM International (2005)
- Electro-galvanized coil (SECC/SECC-N/SECC-AF) product data — Nippon Steel / POSCO / Baosteel (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.