Stainless Steel ZG1Cr18Ni9-ST (Solution annealed)
Heat-treated state · default condition
ASTM CF8
Standard supply condition for pressure-retaining valve and pump castings; carbides dissolved for maximum corrosion resistance and ductility.
Values for the ST condition
Other ZG1Cr18Ni9 tempers and conditions
ZG1Cr18Ni9 is listed in 4 conditions; see the grade overview at ZG1Cr18Ni9.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Cheapest condition for non-pressure, non-corrosive brackets and general hardware; interdendritic carbides reduce corrosion resistance and ductility. | 245 | 480 | 30 | 160 HB | — |
STDefaultThis page Solution annealed | Standard supply condition for pressure-retaining valve and pump castings; carbides dissolved for maximum corrosion resistance and ductility. | 250 | 520 | 55 | 140 HB | — |
Solution annealed then low-temperature stress relieved | Used for thick or weld-repaired castings needing dimensional stability; kept below the sensitization range so corrosion resistance is preserved. | 255 | 515 | 50 | 145 HB | 2.4 % IACS |
Hot isostatically pressed then solution annealed | Choose for high-integrity pressure or cryogenic castings where shrinkage porosity must be closed to raise fatigue life and toughness. | 260 | 545 | 60 | 145 HB | — |
What is ZG1Cr18Ni9-ST?
ZG1Cr18Ni9-ST is ZG1Cr18Ni9 heat treated to ST — standard supply condition for pressure-retaining valve and pump castings; carbides dissolved for maximum corrosion resistance and ductility. ZG1Cr18Ni9-ST has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 193 GPa (28 Msi). ZG1Cr18Ni9-ST has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- Ductile — tolerates forming and impact — 55%, better than 97% of stainless steel grades
- Readily welded — 85/100, better than 87% of stainless steel grades
Limitations
- Low strength — 250 MPa (36.3 ksi), worse than 91% of stainless steel grades
- Hard to polish — 60/100, worse than 80% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
ZG1Cr18Ni9-ST properties
Typical room-temperature values for ZG1Cr18Ni9-ST; 14 are specific to this condition. Other listed values are ZG1Cr18Ni9 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ZG1Cr18Ni9-ST has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
ZG1Cr18Ni9-ST has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
ZG1Cr18Ni9-ST is rated for continuous service to 760°C (1,400 °F). It conducts heat at 16.2 W/m·K (9.36 BTU/hr·ft·°F), better than 64% of stainless steel grades. Thermal expansion is 17.3 µm/m·K (9.61 µin/in·°F).
Electrical3
ZG1Cr18Ni9-ST conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 68% of stainless steel grades.
Sustainability4
Producing a kilogram of ZG1Cr18Ni9-ST takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
ZG1Cr18Ni9-ST's machinability is fair (35/100, better than 51% of stainless steel grades); weldability excellent (85/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZG1Cr18Ni9-ST
Is ZG1Cr18Ni9 easy to machine?
Work-hardens and gums up: use rigid setups, sharp carbide inserts, positive rake, 60–120 m/min, heavy feed and copious coolant; avoid dwelling to prevent glazing.
Can ZG1Cr18Ni9 be welded?
Very good with ER308/E308 (or 308L for repair of low-carbon heats); no preheat, keep interpass low, back-purge and pickle/passivate the weld area.
Can ZG1Cr18Ni9 be formed, bent or molded?
Sand, investment and centrifugal casting all suitable; allow ~2.0–2.3% shrinkage, use generous risers/chills because of long freezing range and hot-tearing tendency.
What surface finishes work on ZG1Cr18Ni9?
Shot blast and pickle (HNO₃-HF) then passivate; electropolishing gives best hygienic finish, plating and painting are rarely needed.
ZG1Cr18Ni9 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 |
|---|---|---|
| CGB old grade sometimes allows ≤0.10 | ≤ 0.08 | 0.06 |
| SiGB/T 2100 often ≤1.50 | ≤ 2 | 1.2 |
| Mn | ≤ 1.5 | 1 |
| P | ≤ 0.04 | 0.03 |
| SGB/T 2100 ZG07Cr19Ni9: S ≤0.030 | ≤ 0.04 | 0.02 |
| Cr | 18 – 21 | 19 |
| Ni | 8 – 11 | 9 |
| Moresidual only; add Mo → CF8M/ZG07Cr19Ni10Mo | ≤ 0.5 | — |
| Fe | balance | — |
ZG1Cr18Ni9-ST — frequently asked
What is ZG1Cr18Ni9-ST used for?
ZG1Cr18Ni9-ST is typically used for valve bodies, pump casings, pipe fittings and general corrosion-resistant castings. In short: baseline cast austenitic; CF8 equivalent; very high cast ductility.
What is the yield strength of ZG1Cr18Ni9-ST?
ZG1Cr18Ni9-ST has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 91% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is ZG1Cr18Ni9-ST easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Work-hardens and gums up: use rigid setups, sharp carbide inserts, positive rake, 60–120 m/min, heavy feed and copious coolant; avoid dwelling to prevent glazing.
Can ZG1Cr18Ni9-ST be welded?
Yes — weldability is rated excellent (85/100). Very good with ER308/E308 (or 308L for repair of low-carbon heats); no preheat, keep interpass low, back-purge and pickle/passivate the weld area.
What surface finishes work on ZG1Cr18Ni9-ST?
Shot blast and pickle (HNO₃-HF) then passivate; electropolishing gives best hygienic finish, plating and painting are rarely needed.
Can ZG1Cr18Ni9-ST be formed, bent or molded?
Sand, investment and centrifugal casting all suitable; allow ~2.0–2.3% shrinkage, use generous risers/chills because of long freezing range and hot-tearing tendency.
What is the maximum service temperature of ZG1Cr18Ni9-ST?
ZG1Cr18Ni9-ST is rated for continuous use to about 760°C (1,400 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZG1Cr18Ni9-ST and ZG1Cr18Ni9-F?
ST is the default condition — standard supply condition for pressure-retaining valve and pump castings; carbides dissolved for maximum corrosion resistance and ductility. F: cheapest condition for non-pressure, non-corrosive brackets and general hardware; interdendritic carbides reduce corrosion resistance and ductility. Yield strength is 250 MPa in ST versus 245 MPa in F.
Sources
- ASTM A351/A351M — Castings, Austenitic, for Pressure-Containing Parts (CF8) — ASTM International (2018)
- ASTM A743/A743M — Castings, Iron-Chromium-Nickel, Corrosion Resistant, General Application — ASTM International (2021)
- GB/T 2100 (ZG07Cr19Ni9) (2017)
- ASM Handbook Vol. 1: Properties and Selection — Cast Stainless Steels — ASM International (1990)
- High-Alloy Data Sheets, Corrosion Resistant Type (CF8) — Steel Founders' Society of America (2004)
- (ZG1Cr18Ni9/CF8 ) (2026)
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.