Page 36 - Welding of Aluminium and its Alloys

28 The welding of aluminium and its alloys

Table 2.4 Hot short range and eutectic characteristics

Alloy system Hot short range Eutectic
composition %
Temp. (°C) Composition (%)
Al-Si 0.5 to 1.2 577 12.6
Al-Cu 2.0 to 4.0 548 33
Al-Mn 1.5 to 2.5 658 1.5
Al-Mg 0.5 to 2.5 450 36
Al-Zn 4.0 to 5.0 381 94
Al-Fe 1.0 to 1.5 655 2
Al-Li Not available 596 7.5
Al-Ni Not available 640 5.7

Aluminium silicon

Aluminium copper

Aluminium magnesium
Crack
sensitivity

Aluminium lithium

Aluminium Mg-Si

0 1 2 3 4 5 6

Percentage of alloying element

2.13 Effect of solute concentration on crack sensitivity.

The aluminium alloys all exhibit a peak in sensitivity with a high resis-
tance to hot cracking at both low and high alloy content, as shown in
Fig. 2.13. At low levels of alloy content there is only a small amount of
eutectic present.This results in the liquid film on the grain boundaries being