6061-T6
Solution treated at about 530 °C, quenched in water and aged at about 160 – 175 °C. Standard temper for most forgings.
General-purpose forging alloy
6061 Aluminium Forgings: Rings, Discs, Bars and Blocks
6061 aluminium forgings combine the alloy's good strength, corrosion resistance and weldability with the toughness and grain flow that only forging gives. 6061 is the easiest heat-treatable alloy to forge, so it is the default choice for rings, flanges, discs, blocks and closed-die parts that do not need aerospace 2xxx or 7xxx strength. Metline supplies 6061 forgings in T6 and T652, as-forged or machined, to customers worldwide.
- Alloy
- 6061 (Al-Mg-Si-Cu)
- Tempers
- T6, T652, T4, O
- Forms
- Rings, discs, blocks, bar, die forgings
- Standards
- ASTM B247 · EN 586
Why forge 6061?
6061 forges at about 430 – 480 °C with a wide working window, low flow stress and little tendency to crack, so it fills complex dies and can be ring-rolled into large, thin-walled rings. After forging it is solution treated, quenched and aged to T6 like any other 6061 product.
The reason to forge instead of machining from plate or extruded bar is grain flow. A plate or bar has grains elongated in one direction; when a ring or flange is cut from it, the grain is cut across at many points around the part, and those points become the weak spots for fatigue and stress corrosion. A rolled ring or forged flange has grains running continuously around the circumference or following the contour of the part, which gives more uniform properties, better fatigue life and higher toughness.
Forging also saves material. Cutting a 1,000 mm ring with a 100 mm wall from plate wastes most of the plate; a rolled ring uses a fraction of the metal. For large rings, discs and thick blocks, a forging is frequently the cheaper route even before the performance benefit is counted.
6061 chemical composition (wt %)
Aluminum Association limits, shared by ASTM B247 and EN 573-3 (EN AW-6061). Forging stock is usually cast or extruded billet; the certificate reports the heat analysis.
| Element | Minimum | Maximum |
|---|---|---|
| Silicon (Si) | 0.40 | 0.80 |
| Iron (Fe) | — | 0.70 |
| Copper (Cu) | 0.15 | 0.40 |
| Manganese (Mn) | — | 0.15 |
| Magnesium (Mg) | 0.80 | 1.20 |
| Chromium (Cr) | 0.04 | 0.35 |
| Zinc (Zn) | — | 0.25 |
| Titanium (Ti) | — | 0.15 |
| Others, each / total | — | 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
Mechanical properties of 6061 forgings
Typical values describe what T6 forgings usually achieve along the grain flow. Specified minimums are lower and are what the purchase specification guarantees; ASTM B247 sets them for die forgings, hand forgings and rolled rings by thickness and test direction.
| Condition | Tensile strength | Yield strength (0.2 %) | Elongation | Hardness |
|---|---|---|---|---|
| 6061-T6, typical | 310 MPa / 45 ksi | 276 MPa / 40 ksi | 12 – 17 % | 95 HB |
| 6061-T6 die forging, minimum (longitudinal, ASTM B247) | 262 MPa / 38 ksi | 241 MPa / 35 ksi | 7 % | — |
| 6061-T4, typical | 240 MPa / 35 ksi | 145 MPa / 21 ksi | 22 % | 65 HB |
| 6061-O, typical | 125 MPa / 18 ksi | 55 MPa / 8 ksi | 25 % | 30 HB |
Transverse and short-transverse minimums and the limits for hand forgings and rings vary with thickness; the governing values for your part are stated on the mill certificate.
Physical properties (T6)
- Density
- 2.70 g/cm³
- Modulus of elasticity
- 68.9 GPa
- Thermal conductivity
- 167 W/m·K
- Electrical conductivity
- 43 % IACS
- Coefficient of thermal expansion
- 23.6 µm/m·°C (20 – 100 °C)
- Melting range
- 582 – 652 °C
T6 or T652: choosing the temper
6061-T652
Solution treated, then cold-compressed 1 – 5 % to relieve quench stresses before ageing. Specified for rings, discs and blocks that will be heavily machined, because they stay round and flat.
6061-T4 / T451
Solution treated and naturally aged. Used when the customer will form the part further or age it after machining.
6061-O / F
Annealed or as-forged. Delivered when the customer carries out their own heat treatment.
Thick forgings cool slowly at the centre during quenching, so their core strength is lower than the surface. For sections thicker than about 100 mm, discuss test locations and expected core properties before ordering, or consider rough-machining before heat treatment so the quench is more effective.
Standards and equivalents for 6061 forgings
| Standard / system | Designation or scope |
|---|---|
| ASTM B247 / B247M | Die forgings, hand forgings and rolled ring forgings |
| SAE AMS | AMS 4127 (6061-T6 forgings and rolled rings); AMS-QQ-A-367 (general forgings); AMS 2770 (heat treatment) |
| EN 586-1/-2/-3 | Forgings: delivery conditions, mechanical properties, tolerances (EN AW-6061, EN AW-AlMg1SiCu) |
| UNS / Werkstoff | A96061 / 3.3211 |
| JIS | A6061 forgings to JIS H4140 |
| ISO | AlMg1SiCu |
In Europe 6082 is the more common 6xxx forging alloy and is often accepted where 6061 is named. If your drawing allows either, say so, as this can widen the available supply and shorten lead time.
6061 forging forms and sizes
Rolled rings
Seamless rings with circumferential grain flow for flanges, bearing housings, slewing rings and vacuum chamber frames.
Forged discs
Upset discs and pancakes for wheels, pulleys, wafer chucks and end plates.
Forged blocks
Rectangular hand forgings for mould bases, manifolds and machine components.
Forged bar and shafts
Round and square bar and stepped shafts forged from large ingots.
Closed-die forgings
Near-net parts such as suspension arms, brackets and housings for volume production.
Forged tube and fittings
Hollow forgings, sleeves and fittings.
Typical supply envelope
- Rolled rings
- Outside diameter from about 200 mm to several metres; wall and height to suit
- Discs
- From about 100 mm to over 1,500 mm diameter
- Blocks and bar
- Sections from about 50 mm to several hundred millimetres, lengths to suit
- Delivery condition
- As-forged, rough-machined, or finish-machined to drawing
Feasible sizes depend on shape and specification. Send a drawing and we will confirm the forging route.
Testing and inspection
Typical inspection plan
- Chemistry
- Heat analysis of the forging stock
- Mechanical
- Tensile tests on prolongations or test rings in the specified directions; hardness on each part
- Ultrasonic
- To ASTM B594 or AMS-STD-2154, class as ordered
- Grain flow
- Macro-etch of a sectioned first article for closed-die parts
- Dimensions
- Checked against the forging or machining drawing
- Certification
- EN 10204 3.1; 3.2 with third-party witness on request
Forging tolerances follow EN 586-3 or the agreed forging drawing. For machined parts, agree the machining allowance and datum surfaces early: a forging with too little allowance may not clean up after heat-treatment distortion, while too much allowance wastes the benefit of forging.
Machining, welding and finishing
Machining
Machines cleanly in T6 with sharp carbide tools. T652 forgings distort least when large volumes are removed.
Welding
Weldable by MIG and TIG with ER4043 or ER5356 filler. The heat-affected zone loses part of its T6 strength unless re-heat-treated.
Anodising
Takes clear, coloured and hard anodising well; common on semiconductor and vacuum parts.
Corrosion
Good resistance in industrial and marine atmospheres; anodise or paint for immersion service.
Where 6061 forgings are used
- Semiconductor and vacuum: chamber rings, lids and wafer chucks where clean machining and anodising matter
- Automotive and transport: suspension arms, knuckles, wheels and brackets
- Marine: fittings, flanges and hardware above or near the waterline
- Industrial machinery: pulleys, gear blanks, slewing rings and hydraulic manifolds
- Oil, gas and chemical: flanges, valve bodies and pressure components (with code approval)
- Aerospace ground equipment: fittings and secondary structures
6061 forgings compared with 6082, 2014 and 7075
| Property | 6061-T6 | 6082-T6 | 2014-T6 | 7075-T6 / T73 |
|---|---|---|---|---|
| Typical tensile strength | 310 MPa | 310 – 340 MPa | About 480 MPa | 570 / 505 MPa |
| Forgeability | Excellent | Excellent | Good | Fair |
| Weldability | Good | Good | Poor | Poor |
| Corrosion resistance | Very good | Very good | Low | Low – moderate |
| Relative cost | Low | Low | Medium | High |
Move up to 2014 or 7075 forgings when strength drives the design; see our 7075 forgings page. For the alloy in other wrought forms, see the 6061 alloy guide.
How to order 6061 forgings
- SpecifyDrawing or dimensions, alloy and temper (6061-T6 or T652), specification (ASTM B247, AMS 4127, EN 586), test directions, UT class and quantity.
- ReviewWe propose the forging route, machining allowance and inspection plan.
- First articleFor new closed-die parts, a first article with dimensional and grain-flow results can be supplied.
- DocumentEN 10204 3.1 certificate with chemistry, heat treatment and test results, plus inspection reports.
- ShipProtected and crated for export, shipped EXW, FOB, CIF or DAP.
References and standards
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- EN 586-2 – Aluminium and aluminium alloys: forgings, mechanical properties
- SAE AMS 2770 – Heat Treatment of Wrought Aluminum Alloy Parts
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM Handbook, Vol. 14A – Metalworking: Bulk Forming
6061 aluminium (aluminum) forgings: frequently asked questions
Is a 6061 forging stronger than 6061 plate?
Typical T6 strength is similar, but a forging has better fatigue life, toughness and more uniform properties because its grain follows the part shape. For rings and flanges that difference is significant.
What is the difference between 6061-T6 and T652 forgings?
Both are solution treated and aged. T652 forgings are also compressed 1 – 5 % after quenching to relieve residual stress, so they distort less during machining.
Can 6061 forgings be welded?
Yes, with ER4043 or ER5356 filler by MIG or TIG. Allow for reduced strength in the heat-affected zone, or re-heat-treat the assembly.
When is a rolled ring better than a ring cut from plate?
Generally above about 300 mm diameter, or whenever the ring is fatigue-loaded. The rolled ring uses less metal and has continuous circumferential grain flow.
What specification should I quote for 6061 forgings?
ASTM B247 for general industrial forgings, AMS 4127 or the drawing's AMS specification for aerospace, and EN 586 for European projects. Include test directions and any UT class.
Do you supply machined 6061 forgings?
Yes. Forgings can be supplied as-forged, rough-machined or finish-machined to drawing, with dimensional reports, and shipped worldwide.
Need 6061 forgings?
Send your drawing, temper and specification. We will propose a forging route and quote a delivered price with full certification.
