1.15 Repair methods
1.15.11 Welding defects
Cracks
The most common types of cracks in aluminium are cracks
caused by heat and/or solidification; the risk of crack formation
increases with increasing solidification.
Cracking in welds is primarily influenced by the composition
of alloys being welded. There is a risk of crack formation with
AlMgSi type aluminium alloys and with AlMg and AlMgMn alloys
with an Mg and/or Si content lower than 2.5%. As a result, these
alloys may only be welded using welding additives made from
alloys with a higher Mg and/or Si content, as these additive
wires increase the residual melt content in the weld pool.
In addition to the use of inappropriate additive materials,
other cause for cracks include excessively shallow craters,
excessively short tack welds or incorrect welding sequences,
resulting in high shrinking stress in the event of sheet
overheating or tension.
Subsequent processes performed on the welds may also
cause the formation of cracks.
For instance, cracks will form around weld beads in the event
of using excessively high weld currents or inappropriate
electrode wires
(Fig. A)
.
Cracks in the end crater are usually caused by inappropriate
finishing treatments
(Fig. B)
.
A
B
Copyright ©
2010
Summary of Contents for 458 Italia
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Page 522: ...Hook 95977564 AS 107564 for lifting the gearbox Page 5 of 5 Specific tooling and equipment ...
Page 586: ...In preparation Page 6 of 6 Engine overhaul Disassembly ...
Page 620: ...Perform the Fuel tank tightness test cycle Page 4 of 4 Fuel level sensor ...
Page 967: ...Refit the wheels D2 01 Page 10 of 10 Stabiliser bars Tie rods ...
Page 1127: ...Refit the wheels D2 01 Page 8 of 8 Wheelhouse ...
Page 1167: ...Prise out and remove the plug 4 Undo the nut 5 Undo the nut 6 Page 32 of 37 Doors ...
Page 1242: ...In the LOWEST position two movements are possible Page 8 of 12 Seats ...
Page 1243: ...In the INTERMEDIATE LOW position three movements are possible Page 9 of 12 Seats ...
Page 1244: ...In the INTERMEDIATE HIGH position three movements are possible Page 10 of 12 Seats ...
Page 1549: ...Reconnect the battery F2 01 Page 5 of 5 Starter motor ...
Page 1721: ...Charge the air conditioning system F5 12 Page 5 of 5 Condenser ...
Page 1740: ...Refit Page 13 of 13 A C unit ...
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