How Much Stronger is Arc Welding than MIG Welding?

The strength of a weld is influenced by numerous factors such as the materials being welded, the welding technique used, the skill of the welder, and the parameters set during welding. While the strength of a weld can vary based on these factors, there are general differences between arc welding (often referred to as Shielded Metal Arc Welding or SMAW) and metal inert gas (mig) welding (GMAW).

Welding Process

.arc Welding:

Typically involves a consumable electrode that melts and fuses the base metals together, producing strong and high-quality welds. It is especially effective for thicker materials.

MIG Welding:

Uses a continuous wire electrode and an inert gas to shield the weld pool, making it faster and easier to use for thinner materials.

Strength

arc Welding:

Generally produces stronger welds in thicker sections and for certain materials, particularly ferrous metals. Welds from arc welding can achieve good penetration and are less prone to defects.

MIG Welding:

While MIG welding can produce strong welds, they may not always reach the strength of arc welds, especially in thicker materials or under specific conditions. However, MIG welding can produce clean and aesthetically pleasing welds.

Applications

arc Welding:

Commonly used in heavy industry, construction, and repair work where strong joints are critical. It is ideal for heavier and thicker materials.

MIG Welding:

Widely used in manufacturing and automotive repair due to its speed and ease of use. It is more suitable for thinner materials and faster assembly lines.

Material Considerations

While both arc welding and MIG welding can achieve similar tensile strengths, the choice between the techniques often depends on the material being welded. For instance, the ER70S-6 electrode for MIG and TIG welding has a tensile strength of 70,000 PSI, which is comparable to E7018. Guaranteeing a welded joint can withstand the pressure exerted by a small car.

However, there are variations in filler metal strengths; certain sticks can achieve up to 100,000 PSI. The choice of filler metal largely depends on the material being welded.

Preferred Techniques for Specific Applications

For tasks requiring deep penetration in thicker materials, such as municipal piping in the 6GR position, MIG welding is a suitable choice. Stainless steel repair and root passes can also be efficiently handled with MIG welding. For applications involving hot passes and subsequent fills or caps, a higher-strength filler like E7018 can be selected.

It's important to note that different welding techniques may be required for various materials or weld positions. For instance, while short arc welding can be used for most jobs, spray transfer, which requires 100% argon, is necessary for thick materials or aluminum, achieving better penetration and reducing the risk of lack of fusion.

Conclusion

The strength of a weld is highly dependent on the specific job and the material being worked with. Both arc welding and MIG welding can produce strong and durable welds, but the choice between the two should be based on the project's requirements, including material thickness, joint design, and desired properties. Understanding the nuances of each technique will help in selecting the most appropriate method for your welding project.