Stainless Steel 316C12-AC (Spheroidize annealed)
Heat-treated state
EN 316C12 · ASTM CF8M
Only for non-critical, non-corrosive or purely mechanical castings — grain-boundary carbides leave the part sensitized.
Values for the AC condition
Other 316C12 tempers and conditions
316C12 is listed in 3 conditions; see the grade overview at 316C12.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
STDefault Solution annealed | The standard supply condition for all pressure-retaining and corrosion-service castings; carbides dissolved for maximum intergranular corrosion resistance. | 260 | 530 | 45 | 155 HB | — |
Hot isostatically pressed then solution treated | Choose for fatigue- or leak-critical valve/pump castings where internal microporosity must be closed. | 270 | 550 | 50 | 155 HB | 2.3 % IACS |
ACThis page Spheroidize annealed | Only for non-critical, non-corrosive or purely mechanical castings — grain-boundary carbides leave the part sensitized. | 275 | 540 | 30 | 170 HB | 2.2 % IACS |
What is 316C12-AC?
316C12-AC is 316C12 heat treated to AC — only for non-critical, non-corrosive or purely mechanical castings — grain-boundary carbides leave the part sensitized. 316C12-AC has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 193 GPa (28 Msi). 316C12-AC has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,390°C (2,534 °F). ST is the default condition FabDigit quotes; AC is available on request or by drawing note.
Limitations
- Limited formability — 18/100, worse than 89% of stainless steel grades
- Low strength — 275 MPa (39.9 ksi), worse than 77% of stainless steel grades
316C12-AC properties
Typical room-temperature values for 316C12-AC; 22 are specific to this condition. Other listed values are 316C12 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
316C12-AC has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,390°C (2,534 °F).
Mechanical16
316C12-AC has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
316C12-AC is rated for continuous service to 480°C (896 °F). It conducts heat at 14.5 W/m·K (8.38 BTU/hr·ft·°F), worse than 72% of stainless steel grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
316C12-AC conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 62% of stainless steel grades.
Sustainability4
Producing a kilogram of 316C12-AC takes about 60 MJ of energy and emits 4.2 kg of CO₂ — more than 70% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
316C12-AC's machinability is poor (33/100, worse than 57% of stainless steel grades); weldability good (58/100); formability poor (18/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 316C12-AC
Is 316C12 easy to machine?
Machine like wrought 316: rigid setup, sharp coated carbide, positive rake, heavy feed and 60–120 m/min to cut under the work-hardened skin, plus flood coolant; expect casting-skin sand/oxide on the first pass.
Can 316C12 be welded?
Readily welded with 316L (ER316L/E316L-16) filler using GTAW/SMAW, no preheat, interpass below 150 °C; re-solution treat after major repair welds if intergranular corrosion service is critical.
Can 316C12 be formed, bent or molded?
Sand, investment and centrifugal casting all suitable; allow ~2.0–2.3% shrinkage, use generous risering and chills because the alloy is mushy-freezing and prone to centreline shrinkage.
What surface finishes work on 316C12?
Passivate (ASTM A967 nitric or citric) or electropolish after machining; shot/bead blasting and pickling remove casting scale — never anodise, and avoid carbon-steel contamination on grinding tools.
316C12 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 |
|---|---|---|
| CBS 3100 316C12 low-to-medium carbon cast grade | ≤ 0.07 | 0.05 |
| Si | ≤ 1.5 | 1 |
| Mn | ≤ 2 | 1 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.04 | 0.02 |
| Cr | 16.5 – 18.5 | 17.5 |
| Ni | 10 – 13 | 11 |
| Mogives the chloride pitting advantage over 304C15 | 2 – 3 | 2.5 |
| Febalance; ferrite content typically 8–20 FN | balance | — |
316C12-AC — frequently asked
What is 316C12-AC used for?
316C12-AC is typically used for valve bodies, pump casings, seawater fittings and chemical process castings. In short: mo-bearing cast 316; better chloride pitting than 304C15; lower temp limit than CF8.
What is the yield strength of 316C12-AC?
316C12-AC has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 77% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 316C12-AC easy to machine?
Not especially — machinability is rated poor (33/100, worse than 57% of stainless steel grades). Machine like wrought 316: rigid setup, sharp coated carbide, positive rake, heavy feed and 60–120 m/min to cut under the work-hardened skin, plus flood coolant; expect casting-skin sand/oxide on the first pass.
Can 316C12-AC be welded?
Yes — weldability is rated good (58/100). Readily welded with 316L (ER316L/E316L-16) filler using GTAW/SMAW, no preheat, interpass below 150 °C; re-solution treat after major repair welds if intergranular corrosion service is critical.
What surface finishes work on 316C12-AC?
Passivate (ASTM A967 nitric or citric) or electropolish after machining; shot/bead blasting and pickling remove casting scale — never anodise, and avoid carbon-steel contamination on grinding tools.
Can 316C12-AC be formed, bent or molded?
Sand, investment and centrifugal casting all suitable; allow ~2.0–2.3% shrinkage, use generous risering and chills because the alloy is mushy-freezing and prone to centreline shrinkage.
What is the maximum service temperature of 316C12-AC?
316C12-AC is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 316C12-ST and 316C12-AC?
ST is the default condition — the standard supply condition for all pressure-retaining and corrosion-service castings; carbides dissolved for maximum intergranular corrosion resistance. AC: only for non-critical, non-corrosive or purely mechanical castings — grain-boundary carbides leave the part sensitized. Yield strength is 260 MPa in ST versus 275 MPa in AC.
Sources
- BS 3100 — Steel castings for general engineering purposes (grade 316C12) — BSI (1991)
- ASTM A351/A351M — Castings, Austenitic, for Pressure-Containing Parts (CF8M) — ASTM International (2018)
- EN 10283 — Corrosion resistant steel castings (1.4408 / GX5CrNiMo19-11-2) — CEN (2010)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- SMM / 1688 stainless casting price levels (2025)
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.