Stainless Steel 1.4640 A2-70
Certified grade
EN 1.4640
A2-70 = finished fastener, property class A2-70
As-delivered bolts/screws headed from this grade, meeting ISO 3506-1 A2-70 strength requirements.
Values for the A2-70 condition
Other 1.4640 tempers and conditions
1.4640 is listed in 8 conditions; see the grade overview at 1.4640.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Hot-rolled and annealed rod/bar — the feedstock condition supplied to wire drawers and forgers. | 225 | 510 | 55 | 145 HB | — |
ADefault Solution annealed | Default stocked condition: soft, maximum ductility for multi-station cold heading of bolts, screws and rivets. | 240 | 520 | 55 | 150 HB | — |
Cold Rolled, annealed & pickled | Cold-rolled soft strip for deep-drawn and stamped parts where a bright, dimensionally accurate surface is needed. | 255 | 540 | 52 | 155 HB | — |
Cold drawn | Annealed-and-drawn CHQ wire with coating (soap/lime or oxalate) — the normal input for header machines and for as-drawn shafts. | 450 | 620 | 30 | 92 HRB | — |
A2-70This page Finished fastener, property class A2-70 | As-delivered bolts/screws headed from this grade, meeting ISO 3506-1 A2-70 strength requirements. | 480 | 730 | 15 | 21 HRC | 2.4 % IACS |
Quarter hard | Light temper rolling/drawing for springy clips and fasteners needing higher proof load with retained bendability. | 520 | 780 | 20 | 23 HRC | 2.4 % IACS |
Half hard | Medium temper for flat springs, washers and formed strip parts where strength dominates over deep forming. | 720 | 950 | 12 | 30 HRC | 2.4 % IACS |
Full hard | Maximum cold-worked strength for wire forms and springs; bending must be across the rolling/drawing direction. | 950 | 1,150 | 6 | 36 HRC | 2.3 % IACS |
What is 1.4640 A2-70?
1.4640 A2-70 is 1.4640 in a A2-70 certified grade — as-delivered bolts/screws headed from this grade, meeting ISO 3506-1 A2-70 strength requirements. 1.4640 A2-70 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 193 GPa (28 Msi). 1.4640 A2-70 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). A is the default condition FabDigit quotes; A2-70 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
- Easy to machine — 45/100, better than 84% of stainless steel grades
- High strength — 480 MPa (69.6 ksi), better than 75% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- Limited ductility — 15%, worse than 89% of stainless steel grades
- Limited formability — 20/100, worse than 86% of stainless steel grades
1.4640 A2-70 properties
Typical room-temperature values for 1.4640 A2-70; 24 are specific to this condition. Other listed values are 1.4640 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4640 A2-70 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
1.4640 A2-70 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
1.4640 A2-70 is rated for continuous service to 300°C (572 °F). It conducts heat at 16.2 W/m·K (9.36 BTU/hr·ft·°F), better than 64% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
1.4640 A2-70 conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 62% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4640 A2-70 takes about 53 MJ of energy and emits 5.2 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 65%.
Manufacturability7
1.4640 A2-70's machinability is fair (45/100, better than 84% of stainless steel grades); weldability good (55/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4640 A2-70
Is 1.4640 easy to machine?
Gummy and work-hardening like 304 (≈45% of AISI 1212) — use sharp positive-rake carbide, heavy constant feed, no dwelling, and flood coolant; free-machining variants are not available in this Cu grade.
Can 1.4640 be welded?
Weldable by GTAW/GMAW/resistance methods with 308L/347 filler, but the low delta-ferrite and copper content raise hot-cracking risk, so keep heat input low and avoid autogenous welds on heavily restrained joints.
Can 1.4640 be formed, bent or molded?
Outstanding cold formability — designed for 4–6 station cold heading, thread rolling and deep drawing with much lower heading pressure and die wear than 302/304; solution anneal at 1040–1100 °C and water quench between severe operations.
What surface finishes work on 1.4640?
Passivate per ASTM A967 (nitric or citric) after heading; electropolishing and mechanical polishing give a bright finish, and zinc/PTFE or Ni coatings are used only where galling or galvanic isolation is required.
1.4640 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≤0.10 in some national grades | ≤ 0.08 | 0.05 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 2 | 1.2 |
| P | ≤ 0.05 | 0.03 |
| Skept low for cold heading | ≤ 0.03 | 0.01 |
| Cr | 17 – 19 | 18 |
| Ni | 8 – 10 | 9 |
| Cuthe defining addition: lowers work-hardening rate | 3 – 4 | 3.5 |
| Nkept low to aid heading | ≤ 0.05 | 0.03 |
| Fe | balance | — |
1.4640 A2-70 — frequently asked
What is 1.4640 A2-70 used for?
1.4640 A2-70 is typically used for cold-headed screws, rivets and wire fasteners. In short: best-heading 18-8 stainless; copper-lowered work hardening; weld with care only.
What is the yield strength of 1.4640 A2-70?
1.4640 A2-70 has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 75% of stainless steel grades. Strength varies by condition: see the 8 listed tempers.
Is 1.4640 A2-70 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 84% of stainless steel grades). Gummy and work-hardening like 304 (≈45% of AISI 1212) — use sharp positive-rake carbide, heavy constant feed, no dwelling, and flood coolant; free-machining variants are not available in this Cu grade.
Can 1.4640 A2-70 be welded?
Yes — weldability is rated good (55/100). Weldable by GTAW/GMAW/resistance methods with 308L/347 filler, but the low delta-ferrite and copper content raise hot-cracking risk, so keep heat input low and avoid autogenous welds on heavily restrained joints.
What surface finishes work on 1.4640 A2-70?
Passivate per ASTM A967 (nitric or citric) after heading; electropolishing and mechanical polishing give a bright finish, and zinc/PTFE or Ni coatings are used only where galling or galvanic isolation is required.
Can 1.4640 A2-70 be formed, bent or molded?
Outstanding cold formability — designed for 4–6 station cold heading, thread rolling and deep drawing with much lower heading pressure and die wear than 302/304; solution anneal at 1040–1100 °C and water quench between severe operations.
What is the maximum service temperature of 1.4640 A2-70?
1.4640 A2-70 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4640-A and 1.4640-FH?
A is the default condition — default stocked condition: soft, maximum ductility for multi-station cold heading of bolts, screws and rivets. FH: maximum cold-worked strength for wire forms and springs; bending must be across the rolling/drawing direction. Yield strength is 240 MPa in A versus 950 MPa in FH.
Sources
- ASTM A493 — Stainless Steel Wire and Wire Rod for Cold Heading and Cold Forging (XM-7 / S30430) — ASTM International (2023)
- EN 10088-3 — Stainless steels: technical delivery conditions for semi-finished products, bars, rods — CEN (2014)
- ISO 3506-1 — Fasteners: mechanical properties of corrosion-resistant stainless steel fasteners (A2 group) — ISO (2020)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Cold heading quality austenitic wire (302HQ/S30430) product data — Sandvik / Outokumpu (2022)
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.