thermexweld exothermic welding user and inspector’s guide “ the good-the bad-the ugly” what is...
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ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
“The Good-The Bad-The Ugly”
What is acceptable?What went wrong?
How to correct.
• What went wrong?– Is it OK?OR– Must it be cut out
and redone?
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• ThermexWELD Exothermic
Joint :
•IS permanent•IS electrically continuous
•IS metallurgically fused.
•WILL carry more currentthan the conductors•WILL NOT loosen•WILL NOT fuse
•Uses PORTABLE TOOLSrequiring no outside power
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
• Section Through an “X” connection:– Showing the full
metallurgical fusion of the conductors.
• Lets look at some practical cases:– What went wrong?– Is it OK?OR– Must it be cut out
and redone?
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Mould Closure:
– Some wire strands displaced from the conductor has prevented the mould closing properly.
– This can happen on both vertically split or horizontally split moulds.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
• Tee weld remade– Note strands
neatly held.– Weld clean.– Weld nicely
formed.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Straight Connection Type
SS1– Weld not formed on the
top.– Cable strands exposed.– Correction:
• Too LITTLE Weld Metal used.….OR
• Weld metal leaked from mould.
• Use CORRECT SIZE as given on Mould Tag.
• NOT ACCEPTABLE as all wire strands are not welded. Remake weld.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide • Straight Connection
Type SS1– Weld fully formed.– Excess metal in the
riser.
– Correction:• Too LARGE a Weld
Metal.• Use CORRECT SIZE as
given on Mould Tag.• ACCEPTABLE as all wire
strands are welded.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Straight Connection
Type SS1– Weld fully formed.– Slight surface slag.
– Correction:• ACCEPTED• Nil required.• Acceptable surface slag
up to 1 mm deep.• Tip: Check that disc is
correctly seated and not dislodged when weld metal is added to crucible.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Guide for
ACCEPT/REJECT:– Correct weld form.– Small riser– Clean– No conductor
exposed– ACCEPTABLE
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Guide for
ACCEPT/REJECT:– Correct weld form.– Tall riser– Clean– No conductor
exposed– ACCEPTABLE
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Guide for
ACCEPT/REJECT:– Correct weld form– No riser– Clean– No conductor
exposed– ACCEPTABLE
minimum level
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Guide for
ACCEPT/REJECT:– Incorrect weld
form– No riser– Clean– Conductor
exposed– REJECT
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• MOULD TAG• Shows:
– ThermexWELD Mould Code
– Weld metal Size– Cable Run– Cable Tap– Gap
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Straight Connection
Type SS1– Weld fully formed.– Dark surface indicates
presence of oil in cable.– Slight surface porosity.
(probably internal porosity as well)
– Correction:• Nil required.• ACCEPTABLE.• Tip: Clean cable with
solvent for next joint.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Tee Connection Type
SS2– Weld not fully formed.– Leak to sides of weld.– Slag present in top of
weld.– Wires not all welded.– Correction:
• Mould not correctly closed, wire in mould parting line OR
• incorrect mould clamp adjustment.
• Check Mould Clamp adjustment.
• REJECT.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Mould Clamp
Adjustment:– Check mould
closure.– Check Mould
handle closing pressure:
• Too tight – loosen off.
• Too loose – tighten---
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
• Mould Handle adjustment continued:– Withdraw the R
Clip in the mechanism.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Mould Handle
adjustment continued:– Screw the adjusting
screw out 1 turn to make the closing “firmer”.
OR– 1 turn in to make the
closing “softer”.– CHECK
• Re-assemble and check mould closure.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
• Mould Clamp adjustment continued:– After adjustment
re-check the handle pressure – a “firm click” to close.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Mould Condition:
– New mould.• Crucible well
defined shape.• Well defined disc
seat.• Note well defined
weld cavity.• Cable holes round.• New mould with
correct care will make 75 to 80 connections.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Mould Condition:• Used/Old mould.
– Crucible worn.– Eroded disc seat.– Chipped and eroded
weld cavity.– Cable holes worn.– Not properly cleaned
after each weld.– Recommendation:
• Replace mould.• Tip: Follow cleaning
procedures with crucible scraper and soft brush in weld cavity.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
• Good appearance:– Why does the
weld appear to be “sleeved” at the ends?
– Acceptable, all welds are like this!-----see next slide.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Tee connection on
steel rod shows the sleeve effect:– Hot metal has
fused the rods in the centre of the joint and cooler metals flows to the side.
– Acceptable weld.
No fusion at ends.Fully fused at rods.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide
• Weld Type SS3– Well formed.– Fully fused.– No porosity.– All welds should
be like this!
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Earth Rod
Connection:– Use the T-241
clamp supplied in the Kit on ALL earth rod connections.
– This clamps holds the mould in place during the welding/exothermic reaction.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide– ThermexWELD
Exothermic products are designed to work as a system and they may not necessarily be compatible with other manufacturer’s products.
– Use ALL the correct tools.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• Weld Metal Size
on the tag MUST match the Weld Metal Size on the Box and on the Container.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• ThermexWELD
Exothermically Welded Joints:– Can be used on:– Copper to Copper– Copper to Steel– Copper to Copper
Jacket Earth Rods– Copper to Pipes– Etc.
ThermexWELD Exothermic WeldingUser and Inspector’s
Guide• For full training instructions see
the ThermexWELD “TRAINING GUIDE”.
• See website www.lectrotech.co.za for a full catalogue.