Steel SK3 Normalized
Heat-treated state
JIS SK3
Used to refine coarse or banded structure before spheroidize annealing/hardening; harder and less machinable than annealed.
Values for the Normalized condition
Other SK3 tempers and conditions
SK3 is listed in 10 conditions; see the grade overview at SK3.
- Annealed
- Normalized
- Cold Drawn
- Cold Rolled Hard
- Q&T 42-46 HRC
- Q&T 48-52 HRC
- Q&T 55-58 HRC
- Q&T 60-63 HRC
- Q&T 63-65 HRC
- As-Quenched
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault spheroidize annealed (soft, as-supplied) | Standard mill-supplied soft condition for machining, blanking and subsequent hardening. | 400 | 670 | 22 | 195 HB | 48 W/m·K |
NormalizedThis page austenitized and air cooled | Used to refine coarse or banded structure before spheroidize annealing/hardening; harder and less machinable than annealed. | 520 | 900 | 10 | 27 HRC | 9 % IACS |
cold drawn/ground bar and drill rod (annealed then drawn) | Precision-size bar and drill rod stock for taps, punches and pins that will be hardened after machining. | 600 | 780 | 10 | 20 HRC | 9.2 % IACS |
work-hardened strip (spring/shim temper) | Hard-rolled high-carbon strip for shims, saw and cutter blanks or springs used without further hardening. | 1,000 | 1,150 | 3 | 39 HRC | 9 % IACS |
Tempered ~500 °C | Highest-toughness tempered condition, used for heavy-shock tools and spring components. | 1,250 | 1,400 | 9 | 44 HRC | 9 % IACS |
Tempered ~400 °C | Impact-loaded tooling (hammers, cold chisels, springs) where toughness outranks wear resistance. | 1,450 | 1,650 | 6 | 50 HRC | 8.8 % IACS |
Tempered ~300 °C | Tougher condition for shear blades, chisels and cold punches subject to impact. | 1,650 | 1,900 | 4 | 56 HRC | 8.5 % IACS |
Tempered ~200 °C | General cutting-tool condition: taps, reamers, punches, woodworking blades — good balance of hardness and chipping resistance. | 1,800 | 2,050 | 2 | 61 HRC | — |
Water quenched, tempered ~150–180 °C | Maximum edge hardness for razors, files, engraving tools and scrapers where toughness is not critical. | 1,900 | 2,200 | 1 | 64 HRC | 40 W/m·K |
water/brine quenched, untempered | Intermediate condition only — maximum hardness but very brittle and residually stressed; must be tempered promptly. | 2,000 | 2,400 | 0 | 65 HRC | 7 % IACS |
What is SK3 Normalized?
SK3 Normalized is SK3 heat treated to Normalized — used to refine coarse or banded structure before spheroidize annealing/hardening; harder and less machinable than annealed. SK3 Normalized has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 67% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi). SK3 Normalized has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,400°C (2,552 °F). Annealed is the default condition FabDigit quotes; Normalized is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to weld — 8/100, worse than 99% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- Difficult to machine — 30/100, worse than 89% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
SK3 Normalized properties
Typical room-temperature values for SK3 Normalized; 22 are specific to this condition. Other listed values are SK3 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SK3 Normalized has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
SK3 Normalized has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 67% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SK3 Normalized is rated for continuous service to 300°C (572 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
SK3 Normalized conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (9/100), worse than 98% of steel grades.
Sustainability4
Producing a kilogram of SK3 Normalized takes about 27 MJ of energy and emits 2.1 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 30%.
Manufacturability7
SK3 Normalized's machinability is poor (30/100, worse than 89% of steel grades); weldability not recommended (8/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SK3 Normalized
Is SK3 easy to machine?
Machine in the spheroidize-annealed condition (~30 % of AISI 1212) with sharp HSS or coated carbide and generous coolant; after hardening only grinding or EDM is practical.
Can SK3 be welded?
Essentially unweldable for structural use — 1.05 % C causes hard brittle HAZ; if repair welding is unavoidable preheat 300–400 °C, use low-hydrogen or Ni filler and temper immediately.
Can SK3 be formed, bent or molded?
Cold blank, bend and coil only in the spheroidized or lightly rolled strip condition with generous bend radii; hot forge 1050–850 °C then slow cool/anneal to avoid network carbide and cracking.
What surface finishes work on SK3?
Takes a fine mirror polish when hardened; no corrosion resistance, so protect with oil, black oxide, phosphate, chrome/nickel plate or nitride — avoid plating/finishing above ~180 °C on low-tempered tools.
SK3 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 G4401 SK3 / SK105 | 1 – 1.1 | 1.05 |
| Si | 0.1 – 0.35 | 0.25 |
| Mn | 0.1 – 0.5 | 0.3 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Curesidual max | ≤ 0.25 | — |
| Niresidual max | ≤ 0.25 | — |
| Crresidual max | ≤ 0.3 | — |
| Fe | balance | — |
SK3 Normalized — frequently asked
What is SK3 Normalized used for?
SK3 Normalized is typically used for taps, dies, hand tools and cutting edges. In short: hardest of the SK grades; water-hardening, unalloyed; edge retention over toughness.
What is the yield strength of SK3 Normalized?
SK3 Normalized has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is SK3 Normalized easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Machine in the spheroidize-annealed condition (~30 % of AISI 1212) with sharp HSS or coated carbide and generous coolant; after hardening only grinding or EDM is practical.
Can SK3 Normalized be welded?
Not readily — weldability is rated not recommended (8/100). Essentially unweldable for structural use — 1.05 % C causes hard brittle HAZ; if repair welding is unavoidable preheat 300–400 °C, use low-hydrogen or Ni filler and temper immediately.
What surface finishes work on SK3 Normalized?
Takes a fine mirror polish when hardened; no corrosion resistance, so protect with oil, black oxide, phosphate, chrome/nickel plate or nitride — avoid plating/finishing above ~180 °C on low-tempered tools.
Can SK3 Normalized be formed, bent or molded?
Cold blank, bend and coil only in the spheroidized or lightly rolled strip condition with generous bend radii; hot forge 1050–850 °C then slow cool/anneal to avoid network carbide and cracking.
What is the maximum service temperature of SK3 Normalized?
SK3 Normalized is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- JIS G 4401 Carbon tool steels (SK105 / former SK3) — JSA (2009)
- ASTM A686 Standard Specification for Carbon Tool Steel (W1) — ASTM (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (Water-hardening tool steels) — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating of Tool Steels — ASM International (1991)
- ASM Handbook Vol.16 — Machining (machinability ratings of tool steels) — ASM International (1989)
- GB/T 1298 (T10A equivalent grade) — SAC (2008)
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.