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FAQ

Here are some of the most frequently asked questions that our company receives regarding general MIG welding issues.

Q: Does shielding gas affect the quality of the finished weld?

A: For most mild steel applications, CO2 will provide adequate shielding, but when you must have a flatter bead profile, less spatter or better wetting action, you may want to consider adding 75 to 90% argon to your CO2 shielding gas mix.

Why? Argon is essentially inert to the molten weld metal and therefore will not react with the molten weld metal. When CO2 is mixed with Argon, the reactivity of the gas is reduced and the arc becomes more stable. But, Argon is more expensive. In production welding, selecting the perfect shielding gas can be a science of its own. Attributes such as material thickness, welding position, electrode diameter, surface condition, welding procedures and others can affect results.

Q: Are there any other tips you can provide for higher quality MIG welding?

A: Try a smaller diameter wire. Although the most common diameters of welding wire are .035" and .045", a smaller diameter wire usually will make it easier to create a good weld. Try an .025" wire diameter, which is especially useful on thin materials of 1/8" or less. The reason? Most welders tend to make a weld that is too big - leading to potential burnthrough problems. A smaller diameter wire welds more stable at a lower current which gives less arc force and less tendency to burn through. If you keep your weld current lower, you will have a greater chance of success on thinner materials. This is a good recommendation for thinner materials; but be careful using this approach on thicker materials (>3/16") because there may be a risk of lack of fusion. Whenever a change like this is made, always verify the quality of the weld meets its intended application.

Q: How important is a good electrical ground in MIG welding?

 A: In arc welding, an arc is established from the electrode to the workpiece. To do this properly, the arc requires a smooth flow of electricity through the complete electrical circuit, with minimum resistance. If you crimp a garden hose while watering the lawn, the flow at the sprinkler head is much reduced. Beginning welders often make the mistake of attaching the work clamp (or electrical ground) to a painted panel or a rusty surface. Both of these surfaces are electrical insulators and do not allow the welding current to flow properly. The resulting welding arc will be difficult to establish and not very stable. Other telltale signs of an improper electrical connection are a work clamp that is hot to the touch or cables that generate heat. Another key point to consider when attaching the welding ground is to place the welding ground on the piece being welded. Welding current will seek the path of least resistance so if care is not taken to place the welding ground close to the arc, the welding current may find a path unknown to the operator and destroy components unintended to be in the welding circuit.

Q: How important is the Contact Tip in MIG welding?

A: Very important. Make sure the gun tip isn't worn out or that weld spatter is not on the tip near the exit hole. The contact tip in the gun should be perfectly round and just a few thousandths larger than the wire itself. Worn tips are typically oval and can cause an erratic arc from the random electrical connection and physical movement of the wire inside the worn tip. Our contact tips are precisely made from a wear-resistant copper alloy for superior welding performance. If the contact tip enters the molten weld pool, it should be immediately replaced. For most casual welders, a good rule of thumb to assure high quality welding is to change the tip after ever 100 lbs. of wire. Another point to remember about contact tips is that they should always be threaded completely into the gas diffuser and tightened prior to welding to give a smooth flow of welding current.

 

Tel: +86 519 85112412
Fax: +86 519 85112412
E-mail: sales@longwelding.com
Add: Donghua Industrial Park,Hutang Town,Wujin District,Changzhou City,Jiangsu Province,China
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