Svetsaren 1/2007 - Esab

ESAB MMA electrodes for positional
welding of thin stainless pipe and sheet
For the petrochemical, paper and pulp, energy
and food processing industries.
TAPIO HUHTALA, ESAB AB, GOTHENBURG, SWEDEN
ESAB introduces three new rutile
MMA electrodes with excellent
all-positions arc control at very low
welding currents - OK 61.20,
OK 63.20 and OK 67.53. They
have been developed in
co-operation with the
petrochemical and paper and pulp
industry - in response to the
increasing use of thin-walled
stainless pipe and sheet to extend
the lifecycle of installations.
Stable arc at low currents
A stable, soft arc at very low current and
voltage makes them suitable for both up- and
downhill welding of pipes with a wall thickness
in the region of 2 mm. The slag system allows a
long pull-out length, reducing electrode change
time loss.
Low spatter, good slag release and good wetting
minimise time loss in post-weld cleaning.
Corrosion resistance meets the requirements of
demanding environments found in, for example,
the petrochemical and shipbuilding industries.
OK 61.20 – for 1.4307 type austenitic
stainless steels
This electrode complements the wellestablished
OK 61.30 to cover very thin
stainless steel. It has been developed for AISI
304 types of austenitic stainless steel widely
used in applications with a moderate corrosion
resistance requirement.
OK 63.20 – for 1.4404 type austenitic
stainless steels
OK 63.20 is used for 1.4404 type stainless
steels (AISI 316) applied in petrochemical plants
and for marine applications. In line with the
parent material, it is alloyed with molybdenum
to provide enhanced resistance to pitting
corrosion in chloride-containing media, such as
salt water. Another major use is the welding of
AISI 304 type stainless steel for similar
applications, to provide a weld with a
significantly higher corrosion resistance.
OK 67.53 – for 1.4462 type austenitic
stainless steels
OK 67.53 is used for welding austenitic-ferritic
(duplex) 1.4462 stainless steel applied extensively
in the petrochemical and pulp and paper
industry, shipbuilding and offshore construction.
It is particularly suitable for bridging large gaps in
thin-walled material.
• Productive welding
• Reduced post weld cleaning
• Good corrosion resistance
in demanding environments
Examples from the industry.
SMAW provides better economy compared to
GTAW, mainly due to the avoidance of gas
purching, related waiting times, and associated
gas costs. The better welding economy makes
MMA electrodes a popular choice for
applications in thin-walled stainless steel.
YIT and Projektsvets, both located in the
Karlstad region of Sweden, specialise in the
construction, repair and maintenance of paper
and pulp plants, in Scandinavia. ESAB’s new
electrodes for thin-walled stainless steel have
been developed to meet their specific
requirements and have been extensively tested
by both companies under practical conditions.
Both report satisfactory use in pipe shops and
on-site applications.
32 - Svetsaren no. 1 - 2007