Steel Y12-CH (Carburized and hardened)
Heat-treated state
GB Y12
Select when a machined free-cutting part needs a wear-resistant case (pins, small shafts, bushings); core stays soft and low strength.
Values for the CH condition
Other Y12 tempers and conditions
Y12 is listed in 6 conditions; see the grade overview at Y12.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Use before severe cold forming, heading or when maximum ductility is needed; machining finish is poorer (gummy). | 230 | 400 | 30 | 115 HB | 11 % IACS |
Hot rolled | Cheapest form; pick for larger-diameter bar that will be fully machined or subsequently cold drawn. | 260 | 450 | 26 | 130 HB | — |
Normalized | Pick to homogenise structure and improve toughness of hot-rolled bar before finish machining. | 270 | 440 | 28 | 130 HB | 10.5 % IACS |
CHThis page Carburized and hardened | Select when a machined free-cutting part needs a wear-resistant case (pins, small shafts, bushings); core stays soft and low strength. | 400 | 600 | 12 | 58 HRC | — |
Cold Drawn + Stress Relieved | Choose when long slender turned parts must stay straight after heavy one-side machining. | 420 | 560 | 13 | 170 HB | 10.5 % IACS |
CDDefault Cold drawn | Standard stock condition: bright, close-tolerance bar with the best surface finish and chip control on multi-spindle automatics. | 450 | 590 | 10 | 180 HB | — |
What is Y12-CH?
Y12-CH is Y12 heat treated to CH — select when a machined free-cutting part needs a wear-resistant case (pins, small shafts, bushings); core stays soft and low strength. Y12-CH has a yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 60% of steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi). Y12-CH 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). CD is the default condition FabDigit quotes; CH is available on request or by drawing note.
Advantages
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- High electrical conductivity — 10.5 % IACS, better than 89% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
Y12-CH properties
Typical room-temperature values for Y12-CH; 10 are specific to this condition. Other listed values are Y12 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Y12-CH 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).
Mechanical14
Y12-CH has a yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 60% of steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
Y12-CH 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
Y12-CH conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (8/100), worse than 99% of steel grades.
Sustainability4
Producing a kilogram of Y12-CH takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
Y12-CH's machinability is poor (25/100, worse than 93% of steel grades); weldability not recommended (10/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Y12-CH
Is Y12 easy to machine?
The benchmark free-cutting steel (100 % rating): run high speeds with light feeds, gives short broken chips and bright finish; keep tool nose sharp to avoid smearing the soft ferrite.
Can Y12 be welded?
Not recommended for structural welds — high S and P cause hot cracking and porosity; if unavoidable use low-hydrogen filler, preheat and minimum restraint.
Can Y12 be formed, bent or molded?
Only light cold bending in the rolling direction; transverse bends and cold heading split along sulphide stringers, so anneal or choose a killed low-C grade instead.
What surface finishes work on Y12?
Takes zinc/nickel plating, black oxide and phosphate well after degreasing; polished surfaces can show inclusion pits, and bare bar must be oiled to prevent rust.
Y12 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 |
|---|---|---|
| C | 0.08 – 0.16 | 0.12 |
| Si | 0.15 – 0.35 | 0.25 |
| Mncombines with S to form free-cutting MnS | 0.7 – 1 | 0.85 |
| Sintentional — chip breaker | 0.1 – 0.2 | 0.15 |
| Pintentional — improves surface finish, embrittles ferrite | 0.08 – 0.15 | 0.11 |
| Crresidual | ≤ 0.1 | — |
| Niresidual | ≤ 0.2 | — |
| Curesidual | ≤ 0.2 | — |
| Fe | balance | — |
Y12-CH — frequently asked
What is Y12-CH used for?
Y12-CH is typically used for screw machine parts, small shafts and fittings. In short: 1212-equivalent free-cutting bar; low-carbon screw stock; not for welded assemblies.
What is the yield strength of Y12-CH?
Y12-CH has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is Y12-CH easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). The benchmark free-cutting steel (100 % rating): run high speeds with light feeds, gives short broken chips and bright finish; keep tool nose sharp to avoid smearing the soft ferrite.
Can Y12-CH be welded?
Not readily — weldability is rated not recommended (10/100). Not recommended for structural welds — high S and P cause hot cracking and porosity; if unavoidable use low-hydrogen filler, preheat and minimum restraint.
What surface finishes work on Y12-CH?
Takes zinc/nickel plating, black oxide and phosphate well after degreasing; polished surfaces can show inclusion pits, and bare bar must be oiled to prevent rust.
Can Y12-CH be formed, bent or molded?
Only light cold bending in the rolling direction; transverse bends and cold heading split along sulphide stringers, so anneal or choose a killed low-C grade instead.
What is the maximum service temperature of Y12-CH?
Y12-CH 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 Y12-CD and Y12-A?
CD is the default condition — standard stock condition: bright, close-tolerance bar with the best surface finish and chip control on multi-spindle automatics. A: use before severe cold forming, heading or when maximum ductility is needed; machining finish is poorer (gummy). Yield strength is 450 MPa in CD versus 230 MPa in A.
Sources
- GB/T 699 / ASTM A108 & SAE J403 (1212 comparison) — SAC / ASTM / SAE (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
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.