Applying poor welding practice to marine pipes can severely impact on their ability to withstand corrosion, even when ‘stainless alloys’ are involved, warns metallurgist and consultant Dr. Michael Fletcher.
Applying poor welding practice to marine pipes can severely impact on their ability to withstand corrosion, even when ‘stainless alloys’ are involved, warns metallurgist and consultant Dr. Michael Fletcher.
Most industries using stainless steel pipes do so because of their corrosion resistance.
The dairy and food sectors are major users since the end products must be contamination free. Pipe and tube joints inevitably contain crevices and any build-up of contaminants here present a potential problem. Large facilities manufactured by major producers such as Alfa Laval AB in Sweden can contain not metres but kilometres of pipes and joints.
Welding Innovation needed to support increasing Global Demand for Power Generation.
Over 300 nuclear reactors have been proposed of which 136 will be in China, 24 in the USA and 23 in Russia 1. India’s massively delayed nuclear power programme will see a resurrection after Électricité de France (EDF), the world’s biggest electricity company, agreed build six nuclear plants in the country.
FIRE SPRINKLER MAINTENANCE BENEFITS from PIPE FREEZING TECHNOLOGY
Automatic sprinkler systems are used more than any other fixed fire protection system and the global fire sprinkler market is expected to reach $11.04 billion by 2020. The annual market growth is estimated at 9.36% between 2015 and 2020 with over 40 million sprinklers fitted worldwide each year.
Synopsis
During heat treatment surface oxide layers, usually called heat tints, are formed on precipitation-hardening nickel-based alloys like UNS N07718. These oxide layers are composed of elements that have been selectively oxidised from the base metal, principally nickel, chromium and iron.
The same phenomenon has been intensively studied on austenitic stainless steels. It is well known that the region beneath the oxide layer is depleted in one or more of the elements that are involved in the scale formation.
An acronym for Wire Arc Additive Manufacturing, WAAM is one of several prominent 3-D printing techniques where significant advances have been made in the last five years. Already established as an alternative production process in the airframe industry WAAM is now making an impact in other manufacturing sectors.
Already attracting massive investment across the world, a recent estimate of from the International Data Corporation indicates that global spending on 3-D printing will grow to $23.0 billion by 2022. This is an increase of over 23% from 2018. China, the UK and the USA spearhead the drive to exploit the potential for 3-D printing but Australia, India and the rest of Europe are also actively examining applications.
A new facility for the production of 1.25 million tonnes of terepthalic acid (PTA) has been built at the port of Mangalore in the Indian state of Karnataka 1.
The project involved factory fabrication of specialised equipment followed by integration on site. A range of stainless steels were used in manufacture along with titanium and tantalum alloys. The bulk of the fabrication involved welding of tubes and pipes.
A significant part of the project was awarded to a Chennai based customer of Weldwell Speciality Pvt Ltd 2 in Mumbai, a major supplier to the Indian welding industry for over two decades. The customer has a long tradition of specialist fabrication of titanium, tantalum, zirconium and nickel alloys and stainless steels.
Mechanical weld backing methods for overcoming weld skill limitations
For most applications of fusion welded joints, it is unnecessary to go to the trouble and expense of ensuring fully continuous transition of metal between parent materials. The fillet weld and the partial penetration butt weld usually are adequate, employed intelligently, they can meet many structural requirements.
Few would disagree with the fact that making high quality welds demands skill. Most metallurgical obstacles have been overcome through progressive development of filler materials. Contemporary equipment for use in GTAW and GMAW is probably as good as it is likely to get. Of the few difficulties remaining, the production of sound and oxide-free weld underbeads is arguably the most underestimated.
Keeping it Clean
Argweld® Flexible Weld Purging Enclosures® make it possible to weld stainless steels, titanium and other reactive alloys effectively without oxidation & discolouration.
Innovation in Weld Protection
The last fifty years has witnessed unprecedented development in welding technology. Major advances in metallurgy resulted in the introduction of new alloys capable of meeting the increasing demands for high strength performance.
Purging for Tubes and Pipes for Improving your Technique
High quality welds in pipes and tubes can only be assured if the weld underbead is protected from oxidation. The various techniques available through which protection can be given is referred to as purging.
Inert Gas Purging with Orbital Welding - World Pipelines & Global Energy
It is often difficult to meet requirements for quality using manual welding. Orbital welding has become an essential process with many tube and pipe fabrications since modern equipment can be fully automatic and reliable and offers repeatable results.
By P C J Anderson at The Welding Institute - Technical Paper Report Nº 220177193
Performance of TIG Electrodes (incorporating MultiStrike® Tungstens)
The increased use of mechanised and fully automated TIG welding techniques has highlighted the demand for improved performance from the tungsten electrode.
By Dr Michael Fletcher of Delta Consultants
Discussing experience with weld purging on stainless steel pipes.
Few would disagree with the fact that making high quality welds in stainless steel demands skill.
Presention at Kuwait Conference
As we entered the 21st C we were made all too familiar with demands to reduce manufacturing costs. Remaining competitive in what had become a global rather than a national economy became a driving force when examining production methods.