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Moisture problem during Electrode Storage

Welding is an important tool for efficient maintenance of plants and quality fabrication in industry. The welding electrode or rod  consists of a metal wire with a baked chemical/mineral coating. The coating of the electrode  holds the key to quality welding. Welding defects caused due to poor quality and weak welding are a nuisance because

 

  • It is unsafe and unreliable
  • Weak welds are dangerous for heavy machinery or large structures
  • It gives a flawed finish

 

Factors effecting the quality of weld

 

     

  • Quality of electrodes-there are different electrodes for different metals,
  • Skill of the person welding the electrode,
  • Electrical contacts -if contact between base metal and clamp is not proper the arc becomes intermittent

 

These are some key elements responsible for the quality of the weld. However  dampness(moisture / humidity) during storage and handling of electrodes is by far the most critical 
factor responsible for quality of weld.  

 

Common moisture problems during Welding Electrode  Storage

 

Moisture wrecks  havoc on the weld. The welding rod consists of a metal core surrounded by a coating of flux. The flux coating controls and improves the welding process. The coating of the electrode  is made of  blends of cellulose, iron powder or low hydrogen and blended with sodium, Titania, potassium and iron oxide. This makes the welding electrode highly hygroscopic and hence  the necessity of proper storage to prevent deterioration of  the coating. Damp electrodes result in a fiery arc, excess splatter of  the weld metal, weld metal at wrong place, weld cracking; making even the most  skilful welder helpless.

 

Common welding defects and problems

 

  • Increased arc voltage
  • Spatter loss (liquid metal expelled from welding process. Spatter leaves behind undesirable dots of metal.)
  • Underbead cracking (which is not directly visible and which may result in premature breaking of  the joint)
  • Poor slag removal
  • Porosity in weld deposit

 

Hydrogen embrittlement: Hydrogen embrittlement is the introduction of  hydrogen in metals during forming and finishing operations. While welding, moisture located at the surface of steel or from filler metal or gas used in welding, dissolves into O2 and H2. While most of the hydrogen from the bead escapes, hydrogen  remains soluble in the region adjacent to the weld. With pressure building  underbead cracking or hydrogen embrittlement follows.

 

In welding of steel, we can minimize underbead cracking by: preheating surface of steels, using low hydrogen electrodes, and allow for a low cooling rate for weld bead to give a chance for hydrogen to escape.

 

Bry-Air increased shelf life of welding electrodes at L&T

 

L&T are leaders in the engineering, technology, construction and manufacturing. Its core businesses are in engineering and construction projects, heavy engineering, power, electrical and electronics, machinery and industrial products, railways, etc.

 

As construction leaders with many awards to its credit, experts at L&T were concerned about the damaging effects of  humidity during electrode storage. Presence of moisture is best avoided in storage rooms it reduces shelf life of welding electrodes and causes welding defects(outlined earlier). A weld  holds the burden of heavy infrastructures and machinery, bridges, flyovers, tall and exquisite buildings, etc. A simple crack in the joint often has far reaching and sometimes even fatal consequences. For superior finish as well as strength and stability, proper storage of electrodes is fundamental. For providing moisture control solutions L&T relied on Bry-Air, a leader in providing dehumidification solutions for over 40 years, world wide. After thorough consideration, Bry-Airgineers arrived at the conclusion that  the most ideal and economical RH for storage of electrodes was 40 ± 5% RH. Bry-Air Compact Desiccant Dehumidifiers were pressed to service. With this welding quality has improved and electrodes also last longer.

 

Bry-Air Dehumidifiers: ensures  longer shelf life of electrodes and eliminates welding defects
Bry-Air Desiccant Dehumidifiers have effectively maintained the exact condition for welding electrode storage not only at L&T but also at Philips, Alsthom Power, Cochin Shipyard, Indian Oxygen, etc. A relative humidity of 40±5% RH at ambient temperature during manufacture, storage prior to packaging, packaging and bulk user storage is essential for retaining the quality of the mineral coating of the welding electrode. Bry-Air's large range of  standard and engineered Dehumidifiers ensure longer shelf life of electrodes.

 

Other key areas where a dehumidification is must

 

  • Bridges Construction
  • Heavy Engineering
  • Metal Fabrication Industry
  • Construction

 

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