Seo welding Tips :Shielding Gases for MIG Welding

Gases are an important part of MIG welding. In fact, they’re the source of the craft’s name: Metal Inert Gas welding. Technically speaking, inert gases are what make MIG welding what it is.

Why Inert Gases?

In short, the role of inert gases is to protect the weld from oxidation. Inert gases and gas mixtures, called “shielding gases” when used for MIG welding, are comprised of elements (in a gaseous state) that aren’t reactive to the elements in the welding wire or the metal(s) being welded. The shielding gas is pumped through the welding gun during welding. It comes through the tip of the gun, completely surrounding both the welding wire and the arc, thereby shielding them from the reactive elements in the air.

Specifically, shielding gases protect the wire electrode and base metals from oxygen, an element that is abundant in the air and problematic for welding. Oxygen is highly reactive with metals, especially commonly welded metals, and it’s even more reactive at the high heat generated by the welding process. When oxygen reacts with the base metals and/or the wire electrode, the resulting oxidation can form anything from a slight film or rusty discoloration to a porous, lumpy, ruined weld joint.

Common Shielding Gases

The four most common gases used in a shielding gas mixture are argon, helium, carbon dioxide, and (surprise!) oxygen. Each gas has its own use, and each comes with benefits and drawbacks for MIG welding, depending on the metals being welded.

Argon must be used without being combined with other elements when welding a non-ferrous (sometimes referred to as “exotic”) materials such as aluminum, magnesium, copper, and titanium. Otherwise, it is commonly mixed with a small portion of carbon dioxide. A mixture high in argon and low in carbon dioxide will often provide a good mixture of arc stability, reduced splatter, narrower penetration, and greater puddle control, all of which make this a potentially good gas mixture for welders looking for a more aesthetically pleasing weld joint that doesn’t require much cleanup.

Helium, like pure argon, is used with non-ferrous metals, as well as stainless steel. Its weld penetration is deep and wide, which makes it ideal for working with thicker materials. Helium is often combined with argon, and the ratio of helium to argon determines the thickness vs. thinness and the depth of the weld penetration. Helium produces a very hot weld, which makes for a relatively fast welding speed, but helium is also relatively expensive.

Carbon dioxide is a reactive gas - not an inert gas - and it is the only reactive gas that can be used for MIG welding without being mixed with at least one other inert gas. It provides a deep weld penetration, which is very useful when welding thicker materials, but it also produces a lot of spatter, requiring more cleanup. Pure carbon dioxide is the least expensive of the common shielding gases, making it a more attractive option for welders working with a tight budget.

Oxygen is, as previously discussed, also a reactive gas. When included in shielding gas mixtures, it’s a small percentage of the mixture. A small amount of oxygen in the gas mixture is beneficial only to certain types of base metals - carbon, low alloy, and stainless steel. In welds with these materials, oxygen can contribute to deeper weld penetration, arc stability, and puddle control. It will still contribute to oxidation in the weld, however, so it has limited applications and should not be used with more reactive metals.

Choosing the Right Shielding Gas

The decision about which shielding gas to use can be as easy or as complicated as the welder wants it to be. The easiest way to choose a shielding gas is to refer to the welding wire’s manufacturer recommendations. Additionally, many MIG welder manufacturers include helpful charts with their welders, and the internet is full of shielding gas selection charts as well. These charts can be a good starting point. Input from a welding supply store or an experienced welder can provide a more dynamic source of input.

Generally, charts and manufacturer recommendations will offer input based on the nature of the weld that the shielding gas options will provide. Cost, however, will likely play a part in discussions with other welders, and this can be an important factor in the decision process.

Seo For :Welding Electrodes

Electrodes are a necessity in welding. Molten metal becomes brittle or has other negative qualities when exposed to air as it absorbs nitrogen and oxygen. Slag covers protect the molten metal during welding from the surrounding atmosphere. The slag cover is usually obtained from the coating of the electrode.

Electrode usability is determined by the coating's composition. The composition of the deposited weld metal and the electrode specification also helps to determine usability. These are important factors to consider when using electrodes.

Electrode coatings are carefully formulated using principles of physics, metallurgy, and chemistry. The coating is very useful as it stabilizes the arc, protects the metal, and improves the weld. The coating improves the weld by minimizing spatter, providing a smooth weld surface that has even edges, making a welding arc that is stable, allowing penetration control, providing a strong and tough coating, easier removal of slag, and an improved deposition rate. All of these factors play an important part in quality welds.

Metal-arc electrodes are grouped as heavy coated or shielded arc electrodes and thinly coated or bare electrodes. In arc welding, covered electrodes are the most popular kind. What kind of electrode is used in a welding job is determined by the properties that are required. These properties are high tensile strength, ductility, corrosion resistance, the base metal, weld position, and the polarity and current required.

Electrodes that are used for welding low alloy and mild steels might have six to twelve ingredients in their coatings. These ingredients include cellulose that provides a gas shield and metal carbonates that will adjust the slag. Titanium dioxide is often included which helps to make slag that is quick freezing but highly fluid. Other ingredients may be ferromanganese, clays, gums, and calcium fluoride. The metals used could be nickel, chromium, or molybdenum and iron or manganese oxide is also often used.

Light coated electrodes are electrodes that have a light coating applied to the surface by brushing, spraying, dipping, washing, wiping, or tumbling. The arc steam's characteristics are improved by the coatings. The coatings reduce or dissolve impurities, makes the molten metal flow and become more uniform, and increases the arc's stability. Some light coatings will create a slag.

Shield arc or heavy coated electrodes have coatings that are applied by extrusion or dipping. There are three general kinds: mineral coatings, cellulose coatings, and a combination of the two. Cellulose coatings provide a gaseous zone around the arc and weld zone to protect it. Mineral coatings create a slag deposit. These kinds of electrodes are used for welding cast iron, steels, and hard surfacing. These coatings increase arc stability, produce a reducing gas shield that surrounds the arc, and reduce impurities that can impair the weld deposit. The electrodes form a slag that solidifies slowly, holds heat, and lets the underlying metal to solidify slowly. This lets impurities float to the surface.

Direct current electrodes are to be used with reverse polarity, straight polarity, or both. Nearly all can be used with alternating current. Reverse polarity usually provides more penetration than straight polarity. Alternating current electrodes are coated electrodes used with alternating or direct current. This type of electrode is preferred in restricted areas or with high currents that are required for thick sections. It is often used in atomic hydrogen welding.

Electrodes come in many varieties and the kind you choose will depend on the area you are working in, the job itself, and the metals that you are using. The wrong kind of electrode can ruin your weld and force you to start all over again. Using the proper one will enable you to work faster, smarter, and have welds that are strong and durable.

Welding In Wet Condition

It’s just bound to happen.

At some point in the course of your welding practice, whether you’re a seasoned professional welder or a home-based project welder, you’re going to encounter wet conditions on a job site or during a project.

As welding safety issues go, properly handling moisture and wet conditions is beyond important because most welding machines (everything but oxyacetylene gas welders) are driven by electricity – and electricity kills! BAM! – one good strong jolt, your heart stops, and that’s all she wrote. And as everyone knows (or should know): water and electricity don’t mix. So the importance of avoiding water or moisture of any kind while you’re welding cannot be stressed enough.

But, as I referenced at the outset of this post, what happens when you encounter moisture from a host of potential sources, or when you’re faced with inclement weather (rain, thunder storms and the like) while welding in the field?

The following is a list of important tips to help keep you safe and alive when you’re welding in wet conditions.

Sweat from Perspiration

Welding is heat intensive hard work – in a word, it’s hot. And combine tSweathat with working outside in summer heat or an overheated welding shop, and you’re going to sweat – there’s just no two ways about it.

Perspiration can adversely affect you in a number of ways:

Gloves

One of the biggest sweat related problems is the perspiration that accumulates in your gloves as you’re welding. Keep in mind, an arc welding electrode is always live, i.e. charged with an active electrical current. If your gloves become saturated with sweat and you touch the electrode you’ve been welding with – WATCH OUT! You’re going to receive a serious jolt.

"If you're working with damp gloves you'll likely feel tingling due to your body becoming part of the electrical path." -- Welding Questions "101" from www.arc-welding-and-beyond.com

Clothing

Just as with your gloves, your clothing can become saturated with perspiration, and if a part of your body sheathed in sweat soaked clothing comes into contact with a live electrode – WHAM-O! You’ll be hit with the same size jolt as you would if you were to touch a live electrode with your sweaty gloves.

Boots

You should always be wearing proper welding boots (for a myriad of important safety reasons beyond moisture related issues) because welding boots have rubber soles, which act as a ground. Being grounded helps minimize the adverse effects of electricity, should you happen to receive a jolt while you’re welding.

If, however, your boots are wet (due to perspiration or because it’s raining and you walked through a puddle) the ground effect of your rubber soled welding boots are negated, because moisture conducts electricity, essentially amplifying the electricity traveling through your body.

In short, always be sure that your gloves, clothing and boots stay dry! If any of the articles of clothing you’re wearing should happen to become wet (for whatever reason) – stop welding – and don’t begin again until you’re completely dry. Rain and Other Inclement Weather

Inclement weather, including thunderstorms and tornado, present a host of issues that can wreak havoc with outdoor or construction site welding projects.

To begin with, basic common sense dictates you shouldn’t be outside in a thunderstorm – if you think the electrical charge from a welding machine packs a whalup, you better hold on to your shorts because a bolt of lightning will literally blow you away.

Additionally, the wind accompanying most storms (thunder or otherwise) can blow away your shield gas, making your welding arc unstable and compromising the integrity of your weld.

Tornados are the same story as thunderstorms – you should be underground, not on a job site, that is unless you want to end up like Dorothy in the Wizard of Oz (just pray Aunt Em’s house doesn’t end up on you). And just as with more generic storms, the wind and other weather related elements symptomatic of a Tornado can blow away your shielding gas and create a host of problems with your welding process.

Getting down to the stated issue at hand, welding in the rain is a big no-no. There are really no circumstances which make welding outdoors or in an open air setting while it’s raining acceptable. Operating a welding machine in the rain is a surefire recipe for death by electrocution.

If you’re in the middle of a welding project when rain hits, immediately discontinue your project, turn off all welding equipment and do your best to get the machine out of the rain or at least covered by a tarp (or whatever you can come up with). Furthermore, do not resume work until the storm has completely broken, and you’re certain all welding equipment is dry.