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Tools/mig/induction: Difference between revisions
→Main level 2 induction: think and thin material guidance
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*** Standard sequence for T-joint (alternating directions on opposite sides) and mitered corners. (round the outside, then across the middle)
* Working with thin (1mm) and thick (5mm) materials
** For thinner materials heat control is vital, it's easy to heat the work up enough to cause massive distortion
*** As with all welding good tacking technique can limit this
*** Welding only in very short bursts
*** Building welds up entirely from tacks (on both sides when possible) is an effective option
*** Very high risk of blow-through if you try to seam weld something
*** Changing to a thinner wire will help, if your wire is thinner than your material it's easier to control
*** sMIG helps enormously here, far easier than manual, but make sure you train it properly first
** For thicker materials the challenge is usually getting enough heat into the material
*** For materials up to 5mm or so then single-pass welding is possible but relatively high power levels will be needed
*** The difficult part is getting enough heat into the work to allow the bead to penetrate fully, without dropping out the bottom
*** Thicker wire will help here by allowing you to add more material to the weld pool at a higher rate
*** A wide weave will be needed in order to make sure the puddle melts into both sides correctly without causing under-cut
**** Undercuts are normally caused by too long an arc, too much power, or failing to pause at the edges of the weave
*** An ideal weld will fill the gap and protrude from the surface by 0-3mm, without any sunken areas or under-cuts
** Multi-pass welding
*** For very thick materials (6mm+) is is likely that this welder will struggle to achieve an acceptable single-pass weld, so multiple passes will be needed
*** Multi-pass welding can be done from one or both sides depending on access. Distortion control will be very much easier if it can be done from both sides
*** Bridge blocks are normally used on multi-pass welds
*** The first pass (called the root) focuses on fully closing the gap at the bottom of the weld with complete penetration, and without causing too much distortion
*** Welds must be cleaned (normally with wire wheel) in between passes
*** Subsequent passes (called fill) are made with a normal welding technique to fill up the grove to just below surface. Alternating sides and directions will help reduce distortion
*** Final pass(s) (called the cap) are made with a much wider than normal weave to finish off the surface and to leave it protruding 0-3mm as for other welds.
* Lap joints of dissimilar thickness and dealing with burn-back issues
* Using tip-dip
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