Stainless Steel 1.4988-SA
Heat-treated state · default condition
EN 1.4988
SA = solution annealed 1080–1150 °C, rapidly cooled
Standard delivery condition for tube, plate and bar; best ductility and corrosion resistance, creep strength develops in service by fine NbC/VC precipitation.
Values for the SA condition
Other 1.4988 tempers and conditions
1.4988 is listed in 4 conditions; see the grade overview at 1.4988.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefaultThis page Solution annealed 1080–1150 °C, rapidly cooled | Standard delivery condition for tube, plate and bar; best ductility and corrosion resistance, creep strength develops in service by fine NbC/VC precipitation. | 300 | 660 | 38 | 180 HB | 2.2 % IACS |
Hot rolled | Cheapest bar/plate form for parts that will be re-solution-annealed or machined all over; scaled surface and scattered properties. | 320 | 680 | 35 | 195 HB | 2.2 % IACS |
Solution annealed and precipitation aged / stabilised ~700–800 °C | Used for creep-loaded fasteners where in-service carbide precipitation is pre-conditioned to stabilise proof strength and relaxation behaviour. | 400 | 720 | 28 | 17 HRC | 2.2 % IACS |
Cold drawn | Choose for high-temperature bolting and studs needing higher proof strength and better surface/tolerance than annealed bar. | 620 | 850 | 18 | 25 HRC | 2.2 % IACS |
What is 1.4988-SA?
1.4988-SA is 1.4988 heat treated to SA — standard delivery condition for tube, plate and bar; best ductility and corrosion resistance, creep strength develops in service by fine NbC/VC precipitation. 1.4988-SA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 38% and the elastic modulus is 200 GPa (29 Msi). 1.4988-SA has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Advantages
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% of stainless steel grades
1.4988-SA properties
Typical room-temperature values for 1.4988-SA; 23 are specific to this condition. Other listed values are 1.4988 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4988-SA has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical16
1.4988-SA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 38% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4988-SA is rated for continuous service to 700°C (1,292 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 59% of stainless steel grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
1.4988-SA conducts electricity at 2.2 % IACS, worse than 61% 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 1.4988-SA takes about 56 MJ of energy and emits 4.6 kg of CO₂ — more than 59% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
1.4988-SA's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability good (55/100); formability good (60/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4988-SA
Is 1.4988 easy to machine?
Machine like a tough 316 but harder: 15–25 % lower speeds, sharp carbide inserts, heavy positive rake, rigid setup and copious coolant, avoid dwelling to prevent work hardening on Nb/V carbides.
Can 1.4988 be welded?
TIG/MIG/SMAW with matched Nb-bearing or 316L/318 filler, low heat input, interpass < 150 °C; keep dilution low to limit hot cracking, no post-weld anneal usually required but heavily restrained joints benefit from re-solution treatment.
Can 1.4988 be formed, bent or molded?
Cold forms well when annealed but work hardens rapidly — allow springback and interstage annealing at 1080–1150 °C; hot work 1150–900 °C with rapid cooling to avoid sigma/carbide precipitation.
What surface finishes work on 1.4988?
Pickle and passivate after hot work or welding to restore the passive film; electropolish or fine mechanical polish for steam-side surfaces; not anodisable — use as-passivated or aluminised for very high-temperature scaling service.
1.4988 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 |
|---|---|---|
| C | 0.04 – 0.1 | 0.07 |
| Si | 0.3 – 0.6 | 0.45 |
| Mn | ≤ 1.5 | 1 |
| P | ≤ 0.04 | — |
| S | ≤ 0.02 | — |
| Cr | 15.5 – 17.5 | 16.5 |
| Ni | 12.5 – 14.5 | 13.5 |
| Mo | 1.1 – 1.5 | 1.3 |
| Vcarbide former for creep strength | 0.6 – 0.85 | 0.7 |
| NbNb+Ta | 0.75 – 1.25 | 1 |
| Fe | balance | — |
1.4988-SA — frequently asked
What is 1.4988-SA used for?
1.4988-SA is typically used for high-temperature bolts, turbine fasteners and pressure vessel studs. In short: high-temperature bolting grade; nb/V creep strengthening; harder to cut than 316.
What is the yield strength of 1.4988-SA?
1.4988-SA has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 68% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4988-SA easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Machine like a tough 316 but harder: 15–25 % lower speeds, sharp carbide inserts, heavy positive rake, rigid setup and copious coolant, avoid dwelling to prevent work hardening on Nb/V carbides.
Can 1.4988-SA be welded?
Yes — weldability is rated good (55/100). TIG/MIG/SMAW with matched Nb-bearing or 316L/318 filler, low heat input, interpass < 150 °C; keep dilution low to limit hot cracking, no post-weld anneal usually required but heavily restrained joints benefit from re-solution treatment.
What surface finishes work on 1.4988-SA?
Pickle and passivate after hot work or welding to restore the passive film; electropolish or fine mechanical polish for steam-side surfaces; not anodisable — use as-passivated or aluminised for very high-temperature scaling service.
Can 1.4988-SA be formed, bent or molded?
Cold forms well when annealed but work hardens rapidly — allow springback and interstage annealing at 1080–1150 °C; hot work 1150–900 °C with rapid cooling to avoid sigma/carbide precipitation.
What is the maximum service temperature of 1.4988-SA?
1.4988-SA is rated for continuous use to about 700°C (1,292 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4988-SA and 1.4988-CD?
SA is the default condition — standard delivery condition for tube, plate and bar; best ductility and corrosion resistance, creep strength develops in service by fine NbC/VC precipitation. CD: choose for high-temperature bolting and studs needing higher proof strength and better surface/tolerance than annealed bar. Yield strength is 300 MPa in SA versus 620 MPa in CD.
Sources
- EN 10302 — Creep resisting steels, nickel and cobalt alloys — CEN (2008)
- DIN 17459 — Seamless circular tubes of creep-resisting austenitic steels — DIN (1992)
- EN 10088-1 — Stainless steels: list of stainless steels — CEN (2014)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Heat-resisting austenitic stainless bar/tube datasheets (specialty steel producers) — various (2023)
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.