Stainless Steel ZG40Cr25Ni20Si2 Aged
Heat-treated state
ASTM HK
Aged = service-aged / thermally exposed
Reference condition for remaining-life and repair assessment of tubes and fixtures after thousands of hours in service — hardened and strongly embrittled at room temperature.
Values for the Aged condition
Other ZG40Cr25Ni20Si2 tempers and conditions
ZG40Cr25Ni20Si2 is listed in 3 conditions; see the grade overview at ZG40Cr25Ni20Si2.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed ~1050–1100 °C, rapid cool | Occasionally specified to homogenise the carbide network, relieve casting stresses and slightly improve room-temperature ductility before machining. | 240 | 470 | 15 | 180 HB | 1.9 % IACS |
FDefault As fabricated | Standard supply condition for furnace fixtures, rolls, trays and radiant-tube parts — used directly with no heat treatment. | 250 | 480 | 10 | 190 HB | 1.9 % IACS |
AgedThis page Service-aged / thermally exposed | Reference condition for remaining-life and repair assessment of tubes and fixtures after thousands of hours in service — hardened and strongly embrittled at room temperature. | 300 | 450 | 3 | 20 HRC | 2.1 % IACS |
What is ZG40Cr25Ni20Si2 Aged?
ZG40Cr25Ni20Si2 Aged is ZG40Cr25Ni20Si2 heat treated to Aged — reference condition for remaining-life and repair assessment of tubes and fixtures after thousands of hours in service — hardened and strongly embrittled at room temperature. ZG40Cr25Ni20Si2 Aged has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 3% and the elastic modulus is 190 GPa (27.6 Msi). ZG40Cr25Ni20Si2 Aged has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,350°C (2,462 °F). F is the default condition FabDigit quotes; Aged is available on request or by drawing note.
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% of stainless steel grades
Limitations
- Limited ductility — 3%, worse than 100% of stainless steel grades
- Limited formability — 2/100, worse than 100% of stainless steel grades
- Low fracture toughness — 28 MPa·√m (25.5 ksi·√in), worse than 99% of stainless steel grades
- Difficult to machine — 18/100, worse than 99% of stainless steel grades
- Difficult to weld — 20/100, worse than 95% of stainless steel grades
ZG40Cr25Ni20Si2 Aged properties
Typical room-temperature values for ZG40Cr25Ni20Si2 Aged; 23 are specific to this condition. Other listed values are ZG40Cr25Ni20Si2 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ZG40Cr25Ni20Si2 Aged has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,350°C (2,462 °F).
Mechanical14
ZG40Cr25Ni20Si2 Aged has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 3% and the elastic modulus is 190 GPa (27.6 Msi).
Thermal6
ZG40Cr25Ni20Si2 Aged is rated for continuous service to 1,100°C (2,012 °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 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
ZG40Cr25Ni20Si2 Aged conducts electricity at 2.1 % IACS, worse than 73% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (56/100), worse than 66% of stainless steel grades.
Sustainability4
Producing a kilogram of ZG40Cr25Ni20Si2 Aged takes about 58 MJ of energy and emits 4.6 kg of CO₂ — more than 66% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
ZG40Cr25Ni20Si2 Aged's machinability is poor (18/100, worse than 99% of stainless steel grades); weldability poor (20/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZG40Cr25Ni20Si2 Aged
Is ZG40Cr25Ni20Si2 easy to machine?
Difficult: hard interdendritic carbides and work hardening — use rigid setups, carbide or ceramic inserts, low speed/heavy positive feed, flood coolant, and avoid dwelling.
Can ZG40Cr25Ni20Si2 be welded?
Weld with matching 25Cr-20Ni (ER310/HK) filler, low heat input and interpass control; hot-crack and post-service embrittlement risk means aged parts often need buttering or carbide-removal grinding first.
Can ZG40Cr25Ni20Si2 be formed, bent or molded?
Casting-only grade — sand, investment and centrifugal routes are all standard; provide generous risers because of the wide freezing range and ~2 % shrinkage.
What surface finishes work on ZG40Cr25Ni20Si2?
Shot blast or pickle to remove scale; passivation improves aqueous corrosion resistance; no coating normally used, service-formed Cr₂O₃/SiO₂ scale is the protective layer.
ZG40Cr25Ni20Si2 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 C gives creep strength via carbide network | 0.3 – 0.5 | 0.4 |
| Siboosts scaling resistance | 1 – 2.5 | 1.8 |
| Mn | ≤ 2 | 1 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 24 – 27 | 25.5 |
| Ni | 19 – 22 | 20.5 |
| Moresidual, restricted in some specs | ≤ 0.5 | — |
| Fe | balance | — |
ZG40Cr25Ni20Si2 Aged — frequently asked
What is ZG40Cr25Ni20Si2 Aged used for?
ZG40Cr25Ni20Si2 Aged is typically used for furnace fixtures, radiant tube supports, petrochemical reformer castings and kiln components. In short: ASTM HK equivalent; 1100 °C service ceiling; cast-only heat-resistant grade.
What is the yield strength of ZG40Cr25Ni20Si2 Aged?
ZG40Cr25Ni20Si2 Aged has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 68% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is ZG40Cr25Ni20Si2 Aged easy to machine?
Not especially — machinability is rated poor (18/100, worse than 99% of stainless steel grades). Difficult: hard interdendritic carbides and work hardening — use rigid setups, carbide or ceramic inserts, low speed/heavy positive feed, flood coolant, and avoid dwelling.
Can ZG40Cr25Ni20Si2 Aged be welded?
Not readily — weldability is rated poor (20/100). Weld with matching 25Cr-20Ni (ER310/HK) filler, low heat input and interpass control; hot-crack and post-service embrittlement risk means aged parts often need buttering or carbide-removal grinding first.
What surface finishes work on ZG40Cr25Ni20Si2 Aged?
Shot blast or pickle to remove scale; passivation improves aqueous corrosion resistance; no coating normally used, service-formed Cr₂O₃/SiO₂ scale is the protective layer.
Can ZG40Cr25Ni20Si2 Aged be formed, bent or molded?
Casting-only grade — sand, investment and centrifugal routes are all standard; provide generous risers because of the wide freezing range and ~2 % shrinkage.
What is the maximum service temperature of ZG40Cr25Ni20Si2 Aged?
ZG40Cr25Ni20Si2 Aged is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZG40Cr25Ni20Si2-F and ZG40Cr25Ni20Si2 Aged?
F is the default condition — standard supply condition for furnace fixtures, rolls, trays and radiant-tube parts — used directly with no heat treatment. Aged: reference condition for remaining-life and repair assessment of tubes and fixtures after thousands of hours in service — hardened and strongly embrittled at room temperature. Yield strength is 250 MPa in F versus 300 MPa in Aged.
Sources
- ASTM A297/A297M Steel Castings, Iron-Chromium and Iron-Chromium-Nickel, Heat Resistant (HK) — ASTM (2019)
- ASM Handbook Vol.1 — Heat-Resistant Cast Steels — ASM International (1990)
- ASM Handbook Vol.13 — Corrosion: High-Temperature Oxidation — ASM International (2005)
- SFSA Steel Castings Handbook — heat resistant alloys — 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.