Material Group 23.1 ISO/TR 15608 such as EN AW-6061:
Heat treatable aluminium-magnesium–silicon alloys.
EN AW-6061 is a typical alloy in this Al-Mg-Si alloy material group. Generally Al-Mg-Si alloys are precipitation-hardened aluminium alloys. They are commonly available in pre-tempered grades such as 6061-T4/T6 with specified yield strength Rp0,2 > 240 MPa (T6).
The most common temper heat treatment (description in EN 515) for 6061 aluminium is:
T4: Naturally aged to a stable condition
T6: Solution heat treated, quenched and artificially aged
Welding of EN AW-6061 alloy.
Welding of The materials are good weldable with the conventional processes (MIG and TIG). When heat treatable aluminium welded, they lose significant amount of their mechanical properties in the heat affected zone (HAZ). If the base metal being welded is in T4 temper, much of the original strength can be recovered after welding by proper post-ageing. If the base metal is welded in the T6- temper, it can be solution heat treated an aged after welding which will restore it to the T6-temper. However, an post weld heat treating an aging may sous additional problems.
EN AW-6061 alloy , the strength of the original T4 or T6 tempers is reduced in the HAZ due the over-heating. Full re-hardening would require a complete solution heat treatment followed by quenching and artificial aging; as result, the welded assembly will most likely be strongly distorted. Partial re-hardening after weldings is possible up to about 40% of the parent strength.
Therefore, it is recommended,
- to keep the energy input per unit length of weld as small as possible( to reduce width of HAZ)
- to weld AlMgSi alloys in the T4 temper followed by age hardening of the complete assembly (if possible).
Applications for : Piping and high pressure gas storage cylinders. According to EN 602, the use of the EN AW-6061 material is allowed for the contact with food.
Applications of Al-Mg-Alloys such EN AW-6061 alloy
Al-Mg-Alloy EN AW-6061is suitable for the manufacture of pressure vessels and piping in accordance with EN 1392 “Aluminum and aluminum alloys – Wrought and cast products – Particular requirements for products for the fabrication of pressure equipment” see table below.
Table: Weldability and pressurised applications for aluminium alloy material group 23.1 in acc. to EN 1392:
| Material | Condition 1 | Weldability | Application | min./max. Working Temp. |
|---|---|---|---|---|
| EN AW-6060 | T42 T6 T8 | yes | Pressure Vessel, Piping Pressure Vessel, Piping Pressure Vessel, Piping | -273/80 °C -273/160 °C -273/160 °C |
| EN AW-6061 | T4 2 T6 | yes | Pressure Vessel, Piping Pressure Vessel, Piping | -273/80 °C -273/160 °C |
| EN AW-6082 | T4 2 T6 T8 | yes | Pressure Vessel, Piping Pressure Vessel, Piping Pressure Vessel, Piping | -273/80 °C -273/160 °C -273/160 °C |
2 If the materials supplied in this condition are exposed to increased temperatures, they will show an increase in strength properties, but the elongation values will decrease.
Typical materials in group 23.1
| Name / Grade | Number | Standard | Products | Remarks |
|---|---|---|---|---|
| EN AW-AlMgSi EN AW-AlMgSi | EN AW-6060 EN AW-6060 | EN 754 EN 755 | Cold drawn rod/bar and tube Extruded rod/bar, tube | EN 13445-8: No EN 13480-8: Yes |
| EN AW-AlMg1SiCu EN AW-AlMg1SiCu EN AW-AlMg1SiCu | EN AW-6061 EN AW-6061 EN AW-6061 | EN 485 EN 754 EN 755 | Plate, sheet, stripe Cold drawn rod/bar and tube Extruded rod/bar, tube | EN 13445-8: No EN 13480-8: Yes |
| EN AW-AlSi1MgMn EN AW-AlSi1MgMn | EN AW-6082 EN AW-6082 | EN 754 EN 755 | Cold drawn rod/bar and tube Extruded rod/bar, tube | EN 13445-8: No EN 13480-8: No |
| 6061 6061 6061 6061 6061 6061 6061 6061 6061 WP6061 6061 | A96061 A96061 A96061 A96061 A96061 A96061 A96061 A96061 A96061 A96061 A96061 | ASTM B-209 ASTM B-210 ASTM B-211 ASTM B-221 ASTM B-234 ASTM B-241 ASTM B-247 ASTM B-308 ASTM B-345 ASTM B-361 ASTM B-547 | Plate & sheet Smls. tube Bar & rod Bar & rod & shape Smls. tube Smls. pipe & tube Forgings Shape Smls. pipe & tube Fittings Welded tube | ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| 6063 6063 6063 6063 WP6063 | A96063 A96063 A96063 A96063 A96063 | ASTM B-210 ASTM B-211 ASTM B-241 ASTM B-345 ASTM B-361 | Smls. tube Bar & rod Smls. pipe & tube Smls. pipe & tube Fittings | ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC |