Product category:
Machinery and Production Equipment
News Release from: Huntingdon Fusion Techniques | Subject: Multi Strike tungsten electrodes
Edited by the Engineeringtalk Editorial
Team on 26 November 2004
Electrodes clean up on orbital welding
operations
Air Products uses Multi Strike tungsten electrodes for its orbital welding applications.
As a leader in the provision of atmospheric gases, process and specialty gases, performance materials and chemical materials, Air Products serves customers in technology, energy, healthcare and industrial markets worldwide It has built leading positions in key growth markets such as semiconductor materials, refinery hydrogen, home healthcare services, natural gas liquefaction and advanced coatings and adhesives and has been a systematic user of Multi Strike tungsten electrodes manufactured by Huntingdon Fusion Techniques for its orbital welding applications
Automated orbital welding is used whenever the quality of the weld joint has the highest priority, a demand which is associated with the aesthetics of the weld, as well as its integrity.
For any user, a uniform, flat and smooth root pass is the main reason for using this process.
For Air Products, high quality pipe welding for the manufacture of clean rooms is a prerequisite.
Air quality in clean rooms is repeatedly filtered to remove dust particles and other impurities that can damage the production of silicon chips, hard disc drives and other technologies such as satellites.
The purity of the air is maintained by controlled gases being delivered into the clean room through stainless steel pipes, which need to have been welded to the highest quality, free of iron dust, to prevent the entry of contaminants.
Air Products uses Multi Strike electrodes for such orbital welding applications.
"Many of the industries we work for require low changes in electrode, as each change in equipment needs to be validated by performing a test piece", says Dave Watson, Quality Engineer at Air Products' office in Wrexham.
"This involves cutting two pieces of pipes, purging it, welding it, cutting it open again and further getting the weld approved before resuming manufacture".
"In addition, we weld with an enclosed weld head to maintain the gas shield, making it difficult to access the tungsten for changing".
"MST electrodes are much longer lasting than standard ones, reducing changes, time and costs and affording us the consistent and high quality welds required in our field".
Multi Strike tungsten resilience is achieved by the choice of dopants used in its manufacture.
Dopants are used to decrease the work function of tungsten.
The most usual, and until now most effective dopant - thoria - lowered tungsten work function to 3.4eV.
Multi Strike electrodes benefit from a considerably lower dopant density, thus improving dopant distribution, enhancing electron emission and enabling electrodes to be activated at only 2.9eV.
This lowered work function increases the usable life of the electrode, while promoting arc stability during welding.
"Orbital welding applications require an accurate arc length, which Multi Strike electrodes provide us with", continues Watson.
A further valuable benefit of Multi Strike electrodes is the noncarcinogenic and environmentally friendly properties of the Multi Strike dopant.
Since health and safety authorities alerted the public about the dangers and effects of the carcinogenic rare earth oxide as found in thoriated TIG welding electrodes, manufacturers have been required to implement and monitor costly and time-consuming health and safety procedures for the storage, grinding, use and disposal of thoriated tungstens.
These include keeping records of the amount of stock in-store and the number of electrodes issued to each welder, instructing on correct and safe usage involving written instructions and verbal presentations, and monitoring each welder.
In addition, thoriated electrodes need to be stored in steel boxes, and the grinding process requires a dedicated grindstone with local dust extraction as well as face masks.
Multi Strike tungsten electrodes present practical advantages and health benefits that cannot be ignored. Request a free brochure from Huntingdon Fusion Techniques ...
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