Stainless Steel ZG40Cr25Ni12Si2 Aged
Heat-treated state
ASTM HH
Aged = aged / service-exposed
Reference condition for design of parts that have seen long exposure at 650–900 °C — strength stays high but room-temperature ductility collapses.
Values for the Aged condition
Other ZG40Cr25Ni12Si2 tempers and conditions
ZG40Cr25Ni12Si2 is listed in 4 conditions; see the grade overview at ZG40Cr25Ni12Si2.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed 1050–1150 °C, water quenched | Choose when maximum room-temperature ductility/impact toughness or machining before service is required; dissolves grain-boundary carbide network. | 280 | 590 | 26 | 170 HB | 1.9 % IACS |
FDefault As fabricated | Standard supply condition for furnace hardware; HH is normally used as-cast because service temperature itself homogenizes the structure. | 310 | 600 | 18 | 185 HB | 1.9 % IACS |
Centrifugally cast tube/ring | Pick for radiant tubes, rolls and rings — columnar centrifugal structure gives sounder walls and somewhat higher strength than static sand casting. | 330 | 640 | 15 | 195 HB | 1.9 % IACS |
AgedThis page Aged / service-exposed | Reference condition for design of parts that have seen long exposure at 650–900 °C — strength stays high but room-temperature ductility collapses. | 380 | 620 | 4 | 19 HRC | 2 % IACS |
What is ZG40Cr25Ni12Si2 Aged?
ZG40Cr25Ni12Si2 Aged is ZG40Cr25Ni12Si2 heat treated to Aged — reference condition for design of parts that have seen long exposure at 650–900 °C — strength stays high but room-temperature ductility collapses. ZG40Cr25Ni12Si2 Aged has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 4% and the elastic modulus is 190 GPa (27.6 Msi). ZG40Cr25Ni12Si2 Aged has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,370°C (2,498 °F). F is the default condition FabDigit quotes; Aged is available on request or by drawing note.
Advantages
- High service temperature — 1,050°C (1,922 °F), better than 91% of stainless steel grades
Limitations
- Limited ductility — 4%, worse than 100% of stainless steel grades
- Limited formability — 3/100, worse than 100% of stainless steel grades
- Difficult to weld — 15/100, worse than 98% of stainless steel grades
- Hard to polish — 45/100, worse than 96% of stainless steel grades
- Difficult to machine — 22/100, worse than 95% of stainless steel grades
ZG40Cr25Ni12Si2 Aged properties
Typical room-temperature values for ZG40Cr25Ni12Si2 Aged; 23 are specific to this condition. Other listed values are ZG40Cr25Ni12Si2 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ZG40Cr25Ni12Si2 Aged has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical15
ZG40Cr25Ni12Si2 Aged has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 4% and the elastic modulus is 190 GPa (27.6 Msi).
Thermal6
ZG40Cr25Ni12Si2 Aged is rated for continuous service to 1,050°C (1,922 °F). It conducts heat at 15.5 W/m·K (8.96 BTU/hr·ft·°F), better than 53% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
ZG40Cr25Ni12Si2 Aged conducts electricity at 2 % IACS, worse than 77% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of ZG40Cr25Ni12Si2 Aged takes about 52 MJ of energy and emits 4.8 kg of CO₂ — less than 76% of stainless steel grades. Typical recycled content is 75%.
Manufacturability7
ZG40Cr25Ni12Si2 Aged's machinability is poor (22/100, worse than 95% of stainless steel grades); weldability poor (15/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZG40Cr25Ni12Si2 Aged
Is ZG40Cr25Ni12Si2 easy to machine?
Machine in the solution-annealed state where possible; use rigid setups, positive-rake carbide (C2/K20 or coated), low speed 15–30 m/min and heavy positive feed to cut under the work-hardened layer, with abundant coolant.
Can ZG40Cr25Ni12Si2 be welded?
Weldable by SMAW/GTAW/FCAW with 25Cr-12Ni (E309/ER309) or over-alloyed 25Cr-20Ni filler; preheat 150–250 °C for heavy or service-aged sections, keep interpass low, and re-solution-treat aged parts before repair welding to avoid σ-phase cracking.
Can ZG40Cr25Ni12Si2 be formed, bent or molded?
Cast only — sand, shell or investment casting with generous risers and chills; no cold forming, and hot straightening must be done above ~1000 °C followed by fast cooling.
What surface finishes work on ZG40Cr25Ni12Si2?
Shot blast and pickle/passivate to remove casting scale; not anodizable, and mechanical polishing is limited by coarse dendritic grains and carbides — a protective in-service Cr₂O₃/SiO₂ scale forms naturally on first heating.
ZG40Cr25Ni12Si2 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 |
|---|---|---|
| Chigh carbon for creep/carbide strengthening | 0.3 – 0.5 | 0.4 |
| Siimproves scaling resistance | 1 – 2.5 | 1.8 |
| Mn | ≤ 2 | 1 |
| Pimpurity | ≤ 0.04 | — |
| Simpurity | ≤ 0.03 | — |
| Cr | 24 – 27 | 25.5 |
| Ni | 11 – 14 | 12.5 |
| Moresidual, restricted | ≤ 0.5 | — |
| Fe | balance | — |
ZG40Cr25Ni12Si2 Aged — frequently asked
What is ZG40Cr25Ni12Si2 Aged used for?
ZG40Cr25Ni12Si2 Aged is typically used for furnace grates, heat-treatment fixtures, burner components and high-temperature process castings. In short: ASTM HH equivalent; lower-nickel heat-resistant casting; stronger than HK.
What is the yield strength of ZG40Cr25Ni12Si2 Aged?
ZG40Cr25Ni12Si2 Aged has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 52% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is ZG40Cr25Ni12Si2 Aged easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% of stainless steel grades). Machine in the solution-annealed state where possible; use rigid setups, positive-rake carbide (C2/K20 or coated), low speed 15–30 m/min and heavy positive feed to cut under the work-hardened layer, with abundant coolant.
Can ZG40Cr25Ni12Si2 Aged be welded?
Not readily — weldability is rated poor (15/100). Weldable by SMAW/GTAW/FCAW with 25Cr-12Ni (E309/ER309) or over-alloyed 25Cr-20Ni filler; preheat 150–250 °C for heavy or service-aged sections, keep interpass low, and re-solution-treat aged parts before repair welding to avoid σ-phase cracking.
What surface finishes work on ZG40Cr25Ni12Si2 Aged?
Shot blast and pickle/passivate to remove casting scale; not anodizable, and mechanical polishing is limited by coarse dendritic grains and carbides — a protective in-service Cr₂O₃/SiO₂ scale forms naturally on first heating.
Can ZG40Cr25Ni12Si2 Aged be formed, bent or molded?
Cast only — sand, shell or investment casting with generous risers and chills; no cold forming, and hot straightening must be done above ~1000 °C followed by fast cooling.
What is the maximum service temperature of ZG40Cr25Ni12Si2 Aged?
ZG40Cr25Ni12Si2 Aged is rated for continuous use to about 1,050°C (1,922 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZG40Cr25Ni12Si2-F and ZG40Cr25Ni12Si2 Aged?
F is the default condition — standard supply condition for furnace hardware; HH is normally used as-cast because service temperature itself homogenizes the structure. Aged: reference condition for design of parts that have seen long exposure at 650–900 °C — strength stays high but room-temperature ductility collapses. Yield strength is 310 MPa in F versus 380 MPa in Aged.
Sources
- ASTM A297/A297M — Steel Castings, Iron-Chromium and Iron-Chromium-Nickel, Heat Resistant, for General Application (Grade HH) — ASTM International (2020)
- ASTM A608/A608M — Centrifugally Cast Iron-Chromium-Nickel High-Alloy Tubing for Pressure Application at High Temperatures — ASTM International (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Heat-Resistant Castings) — ASM International (1990)
- Steel Castings Handbook, High Alloy Data Sheets — Heat Series — Steel Founders' Society of America (2004)
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.