Cu-Tech Exothermic Welding Inspector`s Guide

Report
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
“The Good-The Bad-The Ugly”
What is acceptable?
What went wrong?
How to correct.
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• What went wrong?
– Is it OK?
OR
– Must it be cut out
and redone?
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• ThermexWELD
Exothermic Joint :
•IS metallurgically fused.
•IS permanent
•IS electrically continuous
•WILL carry more current
than the conductors
•WILL NOT loosen
•WILL NOT fuse
•Uses PORTABLE TOOLS
requiring no outside power
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• Section Through an
“X” connection:
– Showing the full
metallurgical fusion
of the conductors.
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• Lets look at some
practical cases:
– What went wrong?
– Is it OK?
OR
– Must it be cut out
and redone?
ThermexWELD
Exothermic Welding
User 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 Welding
User and Inspector’s Guide
• Tee weld remade
– Note strands neatly
held.
– Weld clean.
– Weld nicely formed.
ThermexWELD
Exothermic Welding
User 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 Welding
User 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 Welding
User 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 Welding
User and Inspector’s Guide
• Guide for
ACCEPT/REJECT:
–
–
–
–
Correct weld form.
Small riser
Clean
No conductor
exposed
– ACCEPTABLE
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• Guide for
ACCEPT/REJECT:
–
–
–
–
Correct weld form.
Tall riser
Clean
No conductor
exposed
– ACCEPTABLE
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• Guide for
ACCEPT/REJECT:
–
–
–
–
Correct weld form
No riser
Clean
No conductor
exposed
– ACCEPTABLE
minimum level
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• Guide for
ACCEPT/REJECT:
–
–
–
–
–
Incorrect weld form
No riser
Clean
Conductor exposed
REJECT
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• MOULD TAG
• Shows:
– ThermexWELD
Mould Code
– Weld metal Size
– Cable Run
– Cable Tap
– Gap
ThermexWELD
Exothermic Welding
User 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 Welding
User 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 Welding
User and Inspector’s Guide
• Mould Clamp
Adjustment:
– Check mould
closure.
– Check Mould handle
closing pressure:
• Too tight – loosen off.
• Too loose – tighten---
ThermexWELD
Exothermic Welding
User and Inspector’s Guide
• Mould Handle
adjustment
continued:
– Withdraw the R Clip
in the mechanism.
ThermexWELD
Exothermic Welding
User 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 Welding
User and Inspector’s Guide
• Mould Clamp
adjustment
continued:
– After adjustment recheck the handle
pressure – a “firm
click” to close.
ThermexWELD
Exothermic Welding
User 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 Welding
User 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 Welding
User 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 Welding
User 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 Welding
User and Inspector’s Guide
• Weld Type SS3
–
–
–
–
Well formed.
Fully fused.
No porosity.
All welds should be
like this!
ThermexWELD
Exothermic Welding
User 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 Welding
User 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 Welding
User 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 Welding
User 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 Welding
User and Inspector’s Guide
• For full training instructions see the
ThermexWELD “TRAINING GUIDE”.
• See website www.lectrotech.co.za for a
full catalogue.

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