Full Penetration Welds – How, When, Why

Last Updated on Apr 17, 2022

Challenges inevitably come up when it concerns the process of welding. You’ll encounter new challenges with each assignment, as well as opportunities to learn and make errors. There is no escaping the fact that welding is a difficult process and requires constant practice in order to perfect the art. Welding a piece of metal requires a variety of techniques. Full penetration is a common occurrence throughout a welder’s career. As a result, you’ll want to brush up on your understanding of this popular weld.

This post will teach you about the full penetration weld and get it done correctly and efficiently in the field. So, let’s get right in!


What is a full penetration weld?

Welding two pieces of metal together with no spaces in between is called full penetration welding. Filler material fills the joint’s roots in this kind of weld. Most metal items with great stress resistance use this technology.

In comparison to partial penetration, the strength of the welded product is stronger when using the complete penetration approach. Thus, metal goods with complete penetration are appropriate for high-stress applications.

It’s better to get a thick weld when the weld penetrates all of the ways through the metal. Beveling and penetrating the weld may be accomplished by the use of several weld passes. However, joints with a thickness of 0.20 inches or higher may be penetrated without the need for a groove bevel.

A thick weld that has been beveled and then filled with many weld passes may be considered a complete or full penetration weld, or a sheet metal joint that is.020′′ thick can be considered a complete or full penetration weld.

More than one megawatt per square meter is required for deep penetration. The stronger metal product is a consequence of the enhanced welding resulting from the beam.

Using butt weld, metal bits are melted to the base metal in a full penetration weld. The base metal’s tensile strength is constant from one joint to the next. Single and double variants of this full penetration joint are available.


How to achieve a full penetration weld?

Welding quality may be affected by a variety of circumstances. The quality of a weld may be affected by a variety of things.

Welding current

The primary determinant of weld penetration is the welding current. The larger the weld current, the more penetration there is. This is not the case with a lower welding current.

The wire feed speed may be used to alter the welding current. That is to say, adjusting the gap between the tip and the metal will change the amount of current flowing.

Welding current and tip-to-metal distance are inversely proportional. The current will diminish as you increase the distance from the work piece. Partial penetration will be the effect of this strategy. Full penetration welding may be achieved by shortening your welding tool’s tip-to-metal distance.

The amount of current used to weld the metal pieces may be altered by adjusting the distance between the tip and the metal. It’s important to keep in mind that welding at a certain distance for an extended length of time is not always recommended. The joint spacing should be varied slightly to avoid burning through if there are any discontinuities in the distance.


The placement of the torch.

The degree of perforation is also affected by the location of the welding flame. It is widely understood that, welding current has a far greater impact on the weld quality than arc travel velocity. Typically, the backhand welding technique is more effective than the forehand welding method in terms of penetration depth.

In comparison to forehand welding, backhand welding often achieves a greater penetration depth. The backhand welding and torch angle of 25 degrees provide the best penetration. Arc instability limits deeper penetration if the torch angle is too high.


Stability of the arc

The stability of the arc during welding is another element that influences the level of weld penetration. Deep penetration requires a steady arc. The greater the arc travel speed, the greater the penetration.

With a faster arc travel speed, you may obtain better penetration. 12-inch per minute (ipm) penetration or 30.5-centimeter per minute (cpm) penetration will be achieved (cpm). The penetration decreases at 7 ipm or 17.8 cpm.

If the arc travel speed is more than 17 ipm or 43.2 ipm, the penetration level will also subsequently be reduced. Increasing the welding speed reduces the time it takes for heat produced by welding to melt the base metal. More filler material deposition in the region with a slower arc speed prevents deeper penetration of the liquid weld roll.


Deposition rate

The wire feed speed has an effect on the deposition rate. To get a certain deposition rate, you may tweak the current and the distance between the tip and the metal.

Low wire-feed rate and high welding current might result from a short tip-to-metal distance. As a result, the rate of deposition will be modest, but penetration will be higher. At lower currents, penetration is higher since less metal is deposited at a voltage level.

Tip-to-metal distances of more than one millimeter are ideal for shallow penetration. Deposition rates will be lower, which leads to weaker welds because of this. Arc force will be cushioned by the high weld metal deposit, thus preventing it from penetrating further into the metal.


Proper welder settings and competence are required for deep-penetrating welds. Starting points for voltage, amperage, WFS, and other parameters are provided by welding charts present in the working space. However, there is no alternative for real-world knowledge and understanding.

Also, the full penetration weld is affected by your method. It’s critical that you get your travel angle and speed just correct. Additionally, the thicker stock should have its edges beveled. As a result, you should put in plenty of practice time and ask for help from more experienced welders.