Stainless Steel 1.3960-ST (Solution annealed)
Heat-treated state · default condition
EN 1.3960
Standard supply condition for all corrosion service — dissolves carbides/sigma and restores full intergranular corrosion resistance.
Values for the ST condition
Other 1.3960 tempers and conditions
1.3960 is listed in 4 conditions; see the grade overview at 1.3960.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
STDefaultThis page Solution annealed | Standard supply condition for all corrosion service — dissolves carbides/sigma and restores full intergranular corrosion resistance. | 275 | 550 | 45 | 155 HB | — |
solution treated and hot isostatically pressed | Choose for pressure-retaining or fatigue-critical castings where shrinkage microporosity must be closed. | 285 | 570 | 50 | 158 HB | 2.2 % IACS |
Spheroidize annealed | Only for non-corrosive structural or ornamental use — carbide/sigma networks reduce ductility and intergranular corrosion resistance. | 290 | 520 | 28 | 170 HB | 2.1 % IACS |
centrifugally cast (ASTM A451/A452 practice), solution treated | Tubular/ring parts: denser, finer-grained wall with higher strength than static castings. | 300 | 585 | 42 | 165 HB | 2.2 % IACS |
What is 1.3960-ST?
1.3960-ST is 1.3960 heat treated to ST — standard supply condition for all corrosion service — dissolves carbides/sigma and restores full intergranular corrosion resistance. 1.3960-ST has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 195 GPa (28.3 Msi). 1.3960-ST has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 81% of stainless steel grades. It melts at 1,385°C (2,525 °F).
Advantages
- Readily welded — 80/100, better than 80% of stainless steel grades
- Good corrosion resistance — 74/100, better than 78% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
Limitations
- Hard to polish — 60/100, worse than 80% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
- Low strength — 275 MPa (39.9 ksi), worse than 77% of stainless steel grades
1.3960-ST properties
Typical room-temperature values for 1.3960-ST; 13 are specific to this condition. Other listed values are 1.3960 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.3960-ST has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 81% of stainless steel grades. It melts at 1,385°C (2,525 °F).
Mechanical16
1.3960-ST has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
1.3960-ST is rated for continuous service to 700°C (1,292 °F). It conducts heat at 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 80% of stainless steel grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
1.3960-ST conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (74/100), better than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.3960-ST takes about 55 MJ of energy and emits 5.2 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
1.3960-ST's machinability is fair (38/100, better than 63% of stainless steel grades); weldability very good (80/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.3960-ST
Is 1.3960 easy to machine?
Gummy and work-hardening: use rigid setups, sharp positive-rake carbide, heavy positive feed to cut under the hardened skin, 60–110 m/min with flood coolant.
Can 1.3960 be welded?
Very good weldability with GTAW/SMAW using 317L/ER317L (or overalloyed 309LMo for dissimilar joints); no preheat, interpass <150 °C, and re-solution-treat critical corrosion parts after major weld repair.
Can 1.3960 be formed, bent or molded?
Supplied as sand, investment or centrifugal castings — control gating/risering for the wide freezing range and hold 3–12 % ferrite (FN) to limit hot cracking; not a cold-forming grade.
What surface finishes work on 1.3960?
Pickle and passivate (ASTM A967 / A380) after grinding or weld repair; electropolishing gives the best pitting resistance — no anodizing.
1.3960 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 |
|---|---|---|
| Cextra-low carbon for intergranular corrosion resistance | ≤ 0.03 | 0.02 |
| Si≤1.0 % in EN GX2CrNiMoN grade | ≤ 1.5 | 1 |
| Mn | ≤ 1.5 | 1 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.04 | 0.02 |
| CrASTM CG3M 18.0–21.0; EN 17.0–19.0 | 17 – 21 | 18.5 |
| NiASTM CG3M 9.0–13.0; EN grade ~12.5–14.5 | 9 – 14.5 | 13 |
| Modrives pitting resistance (PREN ≈ 30–36) | 3 – 4 | 3.3 |
| Nnitrogen alloyed in the EN GX2CrNiMoN version; optional in ASTM CG3M | 0.1 – 0.2 | 0.15 |
| Fe | balance | — |
1.3960-ST — frequently asked
What is 1.3960-ST used for?
1.3960-ST is typically used for chemical process pumps, valve bodies and marine fittings. In short: cast 317L pitting resistance; weldable without post-anneal; step up from CF3M.
What is the yield strength of 1.3960-ST?
1.3960-ST has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 77% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.3960-ST easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Gummy and work-hardening: use rigid setups, sharp positive-rake carbide, heavy positive feed to cut under the hardened skin, 60–110 m/min with flood coolant.
Can 1.3960-ST be welded?
Yes — weldability is rated very good (80/100). Very good weldability with GTAW/SMAW using 317L/ER317L (or overalloyed 309LMo for dissimilar joints); no preheat, interpass <150 °C, and re-solution-treat critical corrosion parts after major weld repair.
What surface finishes work on 1.3960-ST?
Pickle and passivate (ASTM A967 / A380) after grinding or weld repair; electropolishing gives the best pitting resistance — no anodizing.
Can 1.3960-ST be formed, bent or molded?
Supplied as sand, investment or centrifugal castings — control gating/risering for the wide freezing range and hold 3–12 % ferrite (FN) to limit hot cracking; not a cold-forming grade.
What is the maximum service temperature of 1.3960-ST?
1.3960-ST 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 1.3960-ST and 1.3960 CENT-ST?
ST is the default condition — standard supply condition for all corrosion service — dissolves carbides/sigma and restores full intergranular corrosion resistance. CENT-ST: tubular/ring parts: denser, finer-grained wall with higher strength than static castings. Yield strength is 275 MPa in ST versus 300 MPa in CENT-ST.
Sources
- ASTM A743/A743M — Castings, Iron-Chromium-Nickel, Corrosion Resistant (grade CG3M) — ASTM International (2019)
- EN 10283 — Corrosion resistant steel castings — CEN (2010)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Steel Founders' Society of America / ACI cast stainless steel property data — SFSA (2015)
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.