Stainless Steel 1.4306 +AT (Solution annealed)
Heat-treated state · default condition
EN 1.4306 · UNS S30403 · AISI/SAE 304L · JIS SUS304L · GB 022Cr19Ni10
Standard stocked condition: maximum ductility, corrosion resistance and weld-decay immunity for plate, tube, bar and heavy-gauge fabrications.
Values for the +AT condition
Other 1.4306 tempers and conditions
1.4306 is listed in 8 conditions; see the grade overview at 1.4306.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ATDefaultThis page Solution annealed | Standard stocked condition: maximum ductility, corrosion resistance and weld-decay immunity for plate, tube, bar and heavy-gauge fabrications. | 260 | 570 | 55 | 150 HB | — |
Cold worked to minimum 700 MPa tensile strength | Light cold-work class for strip and drawn tube/bar needing higher strength while retaining useful ductility for bending. | 430 | 750 | 25 | 22 HRC | — |
Cold drawn | Cold-drawn round/hex bar with better straightness, surface finish and machining behaviour than annealed hot-rolled bar. | 450 | 660 | 30 | 14 HRC | 2.4 % IACS |
Cold worked to minimum 800 MPa tensile strength | Medium cold-work class for springy strip, clamps and structural sections where strength matters more than deep-draw ductility. | 560 | 850 | 16 | 26 HRC | — |
Quarter hard | North-American temper designation for cold-rolled 304L sheet/strip with 515 MPa min yield; use for structural panels and brackets. | 590 | 780 | 14 | 25 HRC | 2.4 % IACS |
Cold worked to minimum 850 MPa tensile strength | Higher cold-work class per EN 10088-2 for thin strip and cold-drawn wire/bar needing high proof strength. | 620 | 900 | 13 | 29 HRC | 2.4 % IACS |
Half hard | Half-hard cold-rolled strip (690 MPa min yield) for flat springs, shims and stiff formed parts with simple bends only. | 760 | 950 | 9 | 32 HRC | 2.4 % IACS |
Cold worked to minimum 1000 MPa tensile strength | Heavily cold-worked thin strip/wire for high-strength springs and straps; very limited bending ability and noticeably magnetic. | 800 | 1,050 | 8 | 34 HRC | 2.4 % IACS |
What is 1.4306 +AT?
1.4306 +AT is 1.4306 heat treated to +AT — standard stocked condition: maximum ductility, corrosion resistance and weld-decay immunity for plate, tube, bar and heavy-gauge fabrications. 1.4306 +AT has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 200 GPa (29 Msi). 1.4306 +AT has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- Readily welded — 95/100, better than 99% of stainless steel grades
- Forms and bends easily — 90/100, better than 98% of stainless steel grades
- Ductile — tolerates forming and impact — 55%, better than 97% of stainless steel grades
- Tough — resists crack growth — 220 MPa·√m (200.2 ksi·√in), better than 97% of stainless steel grades
- Polishes to a fine finish — 85/100, better than 97% of stainless steel grades
Limitations
- Low strength — 260 MPa (37.7 ksi), worse than 84% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
1.4306 +AT properties
Typical room-temperature values for 1.4306 +AT; 17 are specific to this condition. Other listed values are 1.4306 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4306 +AT has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
1.4306 +AT has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4306 +AT is rated for continuous service to 425°C (797 °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
1.4306 +AT conducts electricity at 2.4 % IACS, better than 67% 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 1.4306 +AT takes about 57 MJ of energy and emits 5.5 kg of CO₂ — more than 62% of stainless steel grades. Typical recycled content is 65%.
Manufacturability8
1.4306 +AT's machinability is fair (40/100, better than 72% of stainless steel grades); weldability excellent (95/100); formability excellent (90/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4306 +AT
Is 1.4306 easy to machine?
Gummy and work-hardening: use rigid setups, sharp positive-rake carbide, heavy positive feed to stay under the hardened skin, ~45 % of AISI 1212 speeds and flood coolant.
Can 1.4306 be welded?
Excellent by GTAW/GMAW/SMAW/laser with 308L or 316L filler; low carbon removes any need for post-weld solution annealing, keep interpass ≤150 °C and back-purge for full-penetration root passes.
Can 1.4306 be formed, bent or molded?
Very good deep-drawing and bending (n ≈ 0.45); expect high springback, ~50 % more press force than mild steel, and interstage annealing at 1050 °C + rapid cool for severe draws.
What surface finishes work on 1.4306?
Not anodisable — pickle/passivate to ASTM A967 or electropolish after fabrication; takes No.4 brushed to mirror (No.8) polish readily, and welds should be descaled to restore chloride resistance.
1.4306 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, prevents sensitisation | ≤ 0.03 | 0.02 |
| Si | ≤ 1 | 0.45 |
| Mn | ≤ 2 | 1.4 |
| P | ≤ 0.05 | 0.03 |
| SEN limit; ASTM A240 304L allows 0.030 max | ≤ 0.02 | 0 |
| Cr | 18 – 20 | 18.5 |
| Nihigher Ni than 1.4307 to offset low C | 10 – 12 | 10.5 |
| N | ≤ 0.11 | 0.05 |
| Fe | balance | — |
1.4306 +AT — frequently asked
What is 1.4306 +AT used for?
1.4306 +AT is typically used for welded tanks, pharmaceutical equipment and piping systems. In short: sensitisation-resistant 304; no post-weld anneal needed; poor machinability.
What is the yield strength of 1.4306 +AT?
1.4306 +AT has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 84% of stainless steel grades. Strength varies by condition: see the 8 listed tempers.
Is 1.4306 +AT easy to machine?
Not especially — machinability is rated fair (40/100, better than 72% of stainless steel grades). Gummy and work-hardening: use rigid setups, sharp positive-rake carbide, heavy positive feed to stay under the hardened skin, ~45 % of AISI 1212 speeds and flood coolant.
Can 1.4306 +AT be welded?
Yes — weldability is rated excellent (95/100). Excellent by GTAW/GMAW/SMAW/laser with 308L or 316L filler; low carbon removes any need for post-weld solution annealing, keep interpass ≤150 °C and back-purge for full-penetration root passes.
What surface finishes work on 1.4306 +AT?
Not anodisable — pickle/passivate to ASTM A967 or electropolish after fabrication; takes No.4 brushed to mirror (No.8) polish readily, and welds should be descaled to restore chloride resistance.
Can 1.4306 +AT be formed, bent or molded?
Very good deep-drawing and bending (n ≈ 0.45); expect high springback, ~50 % more press force than mild steel, and interstage annealing at 1050 °C + rapid cool for severe draws.
What is the maximum service temperature of 1.4306 +AT?
1.4306 +AT is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4306 +AT and 1.4306-CD?
+AT is the default condition — standard stocked condition: maximum ductility, corrosion resistance and weld-decay immunity for plate, tube, bar and heavy-gauge fabrications. CD: cold-drawn round/hex bar with better straightness, surface finish and machining behaviour than annealed hot-rolled bar. Yield strength is 260 MPa in +AT versus 450 MPa in CD.
Sources
- EN 10088-1/-2/-3 Stainless steels — technical delivery conditions — CEN (2014)
- ASTM A240/A240M (S30403) plate, sheet and strip — ASTM (2023)
- ASTM A666 annealed or cold-worked austenitic stainless sheet, strip, plate and flat bar — ASTM (2015)
- GB/T 20878 / GB/T 24511 (022Cr19Ni10) — SAC (2007)
- JIS G4304/G4305 (SUS304L) — JSA (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Outokumpu Core 304L/4306 datasheet & Corrosion Handbook — Outokumpu (2023)
- worldstainless / ISSF stainless steel LCI data — ISSF (2021)
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.