Stainless Steel ZG40Cr25Ni12Si2
ASTM HH
ZG40Cr25Ni12Si2 is a 25Cr-12Ni heat-resistant cast austenitic stainless steel equivalent to ASTM Grade HH, with silicon added to improve scaling resistance.
Reference datasheet — ZG40Cr25Ni12Si2 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the F condition
ZG40Cr25Ni12Si2 tempers and conditions
ZG40Cr25Ni12Si2 is supplied in 4 conditions, soft to hard. F is the default FabDigit quotes; the values on this page are for it.
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 |
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?
ZG40Cr25Ni12Si2 is a 25Cr-12Ni heat-resistant cast austenitic stainless steel equivalent to ASTM Grade HH, with silicon added to improve scaling resistance. It is specified for furnace grates and heat-treatment fixtures needing oxidation resistance to 1050 °C at lower nickel content than HK, and is available in F, SA, aged and CF conditions. Typical properties are 310 MPa yield, 600 MPa tensile, 18 % elongation and 185 HB. Aged material loses ductility and should be re-solution treated before repair welding; HK (25Cr-20Ni) is the choice when service temperature or carburizing severity is higher. ZG40Cr25Ni12Si2 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). ZG40Cr25Ni12Si2 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 18% and the elastic modulus is 185 GPa (26.8 Msi).
What is ZG40Cr25Ni12Si2 used for?
- furnace grates
- heat-treatment fixtures
- burner components
- high-temperature process castings
Advantages
- High service temperature — 1,050°C (1,922 °F), better than 91% of stainless steel grades
Limitations
- Hard to polish — 45/100, worse than 96% of stainless steel grades
- Limited formability — 10/100, worse than 95% of stainless steel grades
- Low electrical conductivity — 1.9 % IACS, worse than 84% of stainless steel grades
- Limited ductility — 18%, worse than 83% of stainless steel grades
- Difficult to weld — 40/100, worse than 83% of stainless steel grades
ZG40Cr25Ni12Si2 properties
Typical room-temperature values for ZG40Cr25Ni12Si2-F; bars are the position among stainless steel grades.
Physical3
ZG40Cr25Ni12Si2 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 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 18% and the elastic modulus is 185 GPa (26.8 Msi).
Thermal6
ZG40Cr25Ni12Si2 is rated for continuous service to 1,050°C (1,922 °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 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
ZG40Cr25Ni12Si2 conducts electricity at 1.9 % IACS, worse than 84% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 62% of stainless steel grades.
Sustainability4
Producing a kilogram of ZG40Cr25Ni12Si2 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's machinability is poor (28/100, worse than 79% of stainless steel grades); weldability fair (40/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. ZG40Cr25Ni12Si2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZG40Cr25Ni12Si2
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.
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 |
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.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel ZG40Cr25Ni12Si2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- HH
How much does ZG40Cr25Ni12Si2 cost?
ZG40Cr25Ni12Si2 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
ZG40Cr25Ni12Si2 — frequently asked
What is ZG40Cr25Ni12Si2 used for?
ZG40Cr25Ni12Si2 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?
ZG40Cr25Ni12Si2 has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 63% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is ZG40Cr25Ni12Si2 easy to machine?
Not especially — machinability is rated poor (28/100, worse than 79% 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 be welded?
With care — weldability is rated fair (40/100). 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?
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 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?
ZG40Cr25Ni12Si2 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.
How much does ZG40Cr25Ni12Si2 cost?
ZG40Cr25Ni12Si2 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.