Welder World Blog

Posts Tagged ‘Shielded’

SMAW is commonly referred as shielded metal arc welding. It is also called as Manual Metal Arc (MMA). A consumable electrode which is coated with flux is used to make welds in this type of welding. The electric arc is formed by either using alternating or direct current as a power. This arc is formed between the metal and the electrode to weld. Shielding gas is formed when the flux which was coated on the electrode begins to disintegrate and produce vapors. This gas protects from air contamination too. Here are some basics that a welder ought to know when it comes to arc welding;

Electricity in direct current flows from negative to positive. Direct current is used to produce smooth welding. Electricity passes to and from negative and positive on a sine wave. This results in an irregular passage of current. In turn this results in more spatters.
Reverse polarity is called as Direct Current Electrode Positive (DCEP). Direct Current Electrode Negative (DCEN) is called as straight polarity. Electricity passes with great concentration into the welding rod’s tip to provide just a quarter less that it is capable in DCEP. This gives great incursion. Thick steel pieces can be weld easily with DCEP.

But in DCEN current passes out of the welding rod. There is one third of heat that is concentrated on the rod. This eventually results in less incursive capability. Therefore serves to the best power for thin steel.

There are scores of people who believe that DCEN gives great penetration than DCEP. But with experience you should be able to take sides on your own.

There are a few weld defects that SMAW can cause. They are slag inclusion, undercut and porosity. They are called defects as they weaken the joints where welds are made. Porosity is the holes that appear on the welds. This may be due to gas or steam.

- Slag inclusion happens you don’t chip off the slag. A welder should always get rid of the slag.
- Undercut is the primary mistake that should not happen while welding.
- It is very harmful to weld with exposed skin. Radiations from ultra violet rays can be brutal to your skin. They are capable to blister the cornea of your eyes. Exposing skin while welding leads to skin cancer. The primary reason why heavy welding coats are avoided by welders is because they are uncomfortable. It is not a great reason when compared to the harm that welding can pose on your body.
- Spatter is the molten metal drops that get stuck to the metal all around the place your weld. Spatter will chip off by itself.

Related Shielded Metal Arc Welding Articles

Are you a Canadian Welder? Welder testing is a fact of life for Individuals and Companies working with the structural steel standard: CSA W47.1, Certification of Companies for the Fusion Welding of Steel in Canada today. Whether youre a local welder or a company recruiting welders from outside of Canada, sooner or later you will face the unnecessary stresses related to the world of recruitment, welder training & testing. Here are some reasons why you would want to watch these videos: • No more wasted time and materials • Test Coupons made correctly every time • See and hear the instructions given on test day, well in advance • Welders are mentally and emotionally prepared for test day • Knowledge of the most common failures • Develop fast and cost effective practice techniques • Practicing the Tips and Techniques in this video may help improve overall welding quality. For more information on the videos and test day training visit www.canadianwelder.ca/sales

Learn the basics of shielded arc welding from an arc welding expert in this free DIY video.

Expert: Malcolm MacDonald
Bio: Malcolm MacDonald graduated from Connestoga College in 1968 from the Fitt…