Stainless Steel 1.4878-H (Hardened)
Heat-treated state
EN 1.4878 · UNS S32100 · AISI/SAE 321 · ASTM A240 TP321 · JIS SUS321
Buy this designation when ASME Section VIII/B31.3 elevated-temperature allowables above 540 °C are required; 1.4878 inherently meets the H carbon range.
Values for the H condition
Other 1.4878 tempers and conditions
1.4878 is listed in 7 conditions; see the grade overview at 1.4878.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault solution annealed (1020–1120 °C, rapid cool) | Default stocked condition for plate, sheet, bar, pipe and fittings; maximum ductility and corrosion resistance. | 255 | 600 | 48 | 155 HB | — |
HThis page Hardened | Buy this designation when ASME Section VIII/B31.3 elevated-temperature allowables above 540 °C are required; 1.4878 inherently meets the H carbon range. | 255 | 600 | 45 | 160 HB | 2.4 % IACS |
Stress relieved | Low-temperature relief of cold-work residual stress on formed or machined parts without losing strength or risking sensitization. | 520 | 730 | 30 | 14 HRC | 2.4 % IACS |
Cold drawn | Cold-drawn bar for fasteners and machined parts needing higher yield strength and better surface/tolerance than annealed bar. | 550 | 760 | 28 | 17 HRC | 2.4 % IACS |
Quarter hard | Light temper-rolled sheet for springy brackets and clips still needing moderate bendability. | 570 | 900 | 14 | 25 HRC | 2.4 % IACS |
Half hard | Half-hard strip when high yield strength matters more than forming, e.g. shims and structural clips. | 800 | 1,060 | 10 | 32 HRC | 2.4 % IACS |
Full hard | Maximum-strength thin strip for flat springs and diaphragms; bending only in a limited direction. | 980 | 1,250 | 5 | 38 HRC | 2.4 % IACS |
What is 1.4878-H?
1.4878-H is 1.4878 heat treated to H — buy this designation when ASME Section VIII/B31.3 elevated-temperature allowables above 540 °C are required; 1.4878 inherently meets the H carbon range. 1.4878-H has a yield strength of 255 MPa (37 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 87% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 196 GPa (28.4 Msi). 1.4878-H has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,398°C (2,548 °F). Annealed is the default condition FabDigit quotes; H is available on request or by drawing note.
Advantages
- Readily welded — 85/100, better than 87% of stainless steel grades
- High service temperature — 870°C (1,598 °F), better than 83% of stainless steel grades
- Forms and bends easily — 70/100, better than 79% of stainless steel grades
- Tough — resists crack growth — 190 MPa·√m (172.9 ksi·√in), better than 77% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
Limitations
- Low strength — 255 MPa (37 ksi), worse than 87% of stainless steel grades
1.4878-H properties
Typical room-temperature values for 1.4878-H; 22 are specific to this condition. Other listed values are 1.4878 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4878-H has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,398°C (2,548 °F).
Mechanical16
1.4878-H has a yield strength of 255 MPa (37 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 87% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
1.4878-H is rated for continuous service to 870°C (1,598 °F). It conducts heat at 15.9 W/m·K (9.19 BTU/hr·ft·°F), better than 55% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
1.4878-H conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4878-H takes about 53 MJ of energy and emits 4.5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
1.4878-H's machinability is fair (38/100, better than 63% of stainless steel grades); weldability excellent (85/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4878-H
Is 1.4878 easy to machine?
Gummy and work-hardening like 304 — use rigid setups, positive-rake sharp carbide, heavy constant feed, no dwelling, and generous emulsion or high-pressure coolant; expect ~45 % of AISI 1212 rates.
Can 1.4878 be welded?
Excellent with GTAW/GMAW/SMAW using ER347 or ER321 filler; no post-weld solution anneal needed thanks to Ti stabilization, keep interpass below ~150 °C and avoid high heat input to limit distortion.
Can 1.4878 be formed, bent or molded?
Cold forms, bends, spins and deep draws well but hardens fast — allow 20–40 % more press force than mild steel and interstage anneal at 1020–1080 °C for severe draws; hot work at 1150–900 °C.
What surface finishes work on 1.4878?
Pickle (HNO₃/HF) or passivate per ASTM A967 after welding; electropolish or mechanical polish for hygienic surfaces — Ti carbonitride inclusions can cause faint streaks in mirror finishes; do not anodize.
1.4878 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 |
|---|---|---|
| Chigher C than 1.4541 for creep strength | 0.04 – 0.1 | 0.07 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 2 | 1.2 |
| P | ≤ 0.05 | — |
| S | ≤ 0.02 | — |
| Cr | 17 – 19 | 18 |
| Ni | 9 – 12 | 10.5 |
| Ti≥ 5 × C; stabilizer forming TiC | 0.2 – 0.8 | 0.45 |
| Fe | balance | — |
1.4878-H — frequently asked
What is 1.4878-H used for?
1.4878-H is typically used for exhaust systems, aircraft manifolds, high-temperature piping, expansion bellows and welded pressure vessels. In short: ti-stabilised weld-safe 18-10; 850 °C service temperature; no post-weld anneal needed.
What is the yield strength of 1.4878-H?
1.4878-H has a typical yield strength of 255 MPa (37 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 87% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 1.4878-H easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Gummy and work-hardening like 304 — use rigid setups, positive-rake sharp carbide, heavy constant feed, no dwelling, and generous emulsion or high-pressure coolant; expect ~45 % of AISI 1212 rates.
Can 1.4878-H be welded?
Yes — weldability is rated excellent (85/100). Excellent with GTAW/GMAW/SMAW using ER347 or ER321 filler; no post-weld solution anneal needed thanks to Ti stabilization, keep interpass below ~150 °C and avoid high heat input to limit distortion.
What surface finishes work on 1.4878-H?
Pickle (HNO₃/HF) or passivate per ASTM A967 after welding; electropolish or mechanical polish for hygienic surfaces — Ti carbonitride inclusions can cause faint streaks in mirror finishes; do not anodize.
Can 1.4878-H be formed, bent or molded?
Cold forms, bends, spins and deep draws well but hardens fast — allow 20–40 % more press force than mild steel and interstage anneal at 1020–1080 °C for severe draws; hot work at 1150–900 °C.
What is the maximum service temperature of 1.4878-H?
1.4878-H is rated for continuous use to about 870°C (1,598 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4878 Annealed and 1.4878-FH?
Annealed is the default condition — default stocked condition for plate, sheet, bar, pipe and fittings; maximum ductility and corrosion resistance. FH: maximum-strength thin strip for flat springs and diaphragms; bending only in a limited direction. Yield strength is 255 MPa in Annealed versus 980 MPa in FH.
Sources
- EN 10088-1/-2/-3 Stainless steels — X8CrNiTi18-10 (1.4878) — CEN (2014)
- ASTM A240/A240M — TP321/TP321H plate, sheet and strip — ASTM International (2023)
- ASTM A276 / A312 / A666 — stainless bar, pipe and cold-rolled strip tempers — ASTM International (2022)
- GB/T 20878 / GB/T 4237 — 06Cr18Ni11Ti (321) — SAC (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Outokumpu / Sandvik stainless steel grade datasheets (4878, 321H) — Outokumpu, Alleima (2023)
- SMM / Mysteel — SMM / Mysteel (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.