What are the Types of Weld Joints and Which is the Strongest

For all the years that I’ve been welding, one of the debates that I’ve always heard discussed was which welding joint works the best and which one is the strongest. This is an important discussion because if you use the wrong kind of joint on the wrong project, it can weaken the whole thing. This of course also depends upon the type of welding rod that you’re using and the type of material. You should always select the proper equipment for whatever project you are working on. Having been in woodworking for so many years, welding has become a learned skill so that I can use it in any of the projects that I do.

I don’t typically use all of the types of weld joints. The majority of the time I use a corner joint or a Tee joint to create a particular shape. I am proficient in all the types of joints, it’s something that I have practiced for quite a while and I can tell you that there are one or two that are stronger than the others. However, this can also depend upon your skill level and the material. Done appropriately, most of these joints are sufficiently strong. However, most welders will tell you that a corner or tea joint using a groove to get proper penetration with an arc welder will provide you with the strongest weld. Let’s delve into the different types of joints and take a look at a few of the different welds that you work with.

Butt Weld Joints

Commonly used in a factory environment, this technique is used to attach two pieces of metal. Most commonly this is used to weld pieces such as pipes, flanges, and to build frameworks. Factories use this technique because if you want to create something out of metal without having to weld it, you would have to bend a metal into that shape and reinforce it. This is not cost efficient when it comes to building things like this, so they use Butt welding.

Butt welding is accomplished when you heat up both pieces of metal, applying pressure or doing both. When welding a thin piece of metal, it is possible to maintain penetration. However, if you’re welding a thicker piece of metal you may need to do some edge preparation. There are two kinds of Butt-welding that are used, flash and resistance. Let’s take a look at the two kinds to see if we can get a better understanding of what they are used for.

Resistance Butt Welding

Resistance Butt welding is performed on two pieces of metal by using pressure and heat and then forcing the metals together to create a bond using a preset Force.

Flash Butt Welding

Flash Butt welding is used in machinery to connect metal pieces together that are mismatched in their shape and size. They apply a high voltage current to both pieces and then join them together in a process known as flashing.

What Type of Weld Would I Use

With a butt weld, you will want to use either a TIG welder or a MIG welder due to their ability to connect two pieces together. You can also do this with arc welding, but you should understand the properties of the electrode and the metal being welded. The metal, after all, is what will determine which kind of weld that you need to use.

The following is a list of all the weld’s you can use:

  • U-groove butt weld
  • Bevel-groove butt weld
  • Flare-bevel-groove butt weld
  • Flare-V-groove butt weld
  • Square-groove butt weld
  • V-groove butt weld
  • J-groove butt weld

Corner Weld Joints

Unlike the Butt weld, the corner joint is done at a right angle where two members connect. They create an L shape and are commonly done with three different techniques. Let’s take a look at the different welds and what they’re used for.

Fillet Weld Corner Joint

One of the more common types of a weld is the corner joint which would be used to make things such as box frames, boxes, and other similar projects as those. In this type of weld joint, the two pieces the material meet in the corner leaving the ends exposed and the weld is used to create the corner and connect the two pieces.

Closed Weld Corner Joint

This type of weld is used for lighter materials when high strength is not required. One piece of metal will butt up to the other peace and create a right angle. Oxy-acetylene welding will be used to weld the overlapping edge and create the meltdown. With this type of joint, there will be little or no filler metal used. If it is going to be used in a heavier section, they will create a bevel or a groove that will allow penetration to the root of the joint.

Open Weld Corner Joint

If you’re going to be welding heavier plates or sheets, this will probably be the type of weld you want to use. The plates are positioned with a small opening in an L shape and the weld is used to fill in the corner. This creates a stronger heavier weld. Depending upon how heavy the pieces are, you may also want to weld them from the inside of the corner creating an even stronger weld.

What Type of Weld Would I Use?

About 75% of all corner welds are done with an arc welder. However, they can be performed by many different types of Welds.

The following is a list of the welds that you can use with a corner joint:

  • Spot weld
  • Edge weld
  • Fillet weld
  • V-groove weld
  • Corner-flange weld
  • Square-groove weld or butt weld
  • J-groove weld
  • U-groove weld
  • Bevel-groove weld
  • Flare-V-groove weld

Tee Weld Joints

Tee weld joints are also a very popular way of connecting two pieces. This type of joint is created when two pieces intersect with each other at a 90-degree angle. The first piece butts up to the second piece in the center of the plate giving a T look to the piece. This is a type of Fillet weld and can be used when attaching things such as tubes or pipes to a base plate. With this type of weld, you always want to take extra care to ensure that there is the right amount of penetration into the roof of the connecting plate.

What Type of Weld Would I Use

While this is one of the more common types of well joint there are a few different techniques that you can use to join them together depending upon the strength and look that you’re trying to achieve.

The welds that can be used for the Tee joint are as follows:

  • Plug weld
  • Melt-through weld
  • Fillet weld
  • J-groove weld
  • Bevel-groove weld
  • Flare-bevel-groove weld
  • Slot weld

Lap weld joint

This type of joint is used to join two pieces of metal together with different thicknesses. The joint is formed when the two pieces of metal are placed on top of each other in an overlapping pattern. You then weld along one or both edges according to how strong you would like the joint. With lap joints like other weld joints, it is important to design the joint correctly. For instance, if the load is going to be distributed towards the center of the weld, you want to make sure that both edges are welded and not just one so that it will provide that extra strength and load-bearing ability.

What Type of Weld Would I Use

There are a few different welds that you can use with a lap joint. The most important part of designing a lap joint is the position of the overlapping metals. For instance, you never want the depth of overlap to be less than the width or the joint will be weaker.

Having said that, here are a few of the standard welds for use with this type of joint:

  • Slot weld
  • J-groove weld
  • Plug weld
  • Flare-bevel-groove weld
  • Bevel-groove weld
  • Spot weld

Edge Joints

This type of weld is literally just like it sounds. The Edge joints consist of two pieces of material lined up next to each other and the weld is applied along the edge of both. This weld is typically used in sheet metal parts that are made to go in a location and be welded along the same edge to keep them in place. These parts may have flanged edges to make it easier to line up the pieces and apply the weld. A filling metal may be used to add strength to the weld for the heavier applications. This is done to completely fuse or melt the edges together and reinforce the plate.

What Type of Weld Would I Use

With this type of joint, there are a few different welds that can be used to make the union of these two plates a bit stronger.

The welds include the following:

  • Bevel-groove weld
  • Square-groove weld or butt weld
  • J-groove weld
  • V-groove weld
  • Edge-flange weld
  • U-groove weld
  • Corner-flange weld

Types of Welds

Spot Weld

This type of weld uses multiple separate welds to hold the pieces together. Generally, the Spot weld is used to hold something in place while finishing the permanent weld.

Fillet Weld

Simply known as a lap, corner or tee weld, this technique is used to join two metal pieces that are at an angle or perpendicular. The weld needs to make good penetration into the medal in order for it to have a strong joint.

V-groove Weld

The V groove weld uses two angled pits in the metal that allows the weld to penetrate into the metal and create a stronger bond. If you look at the pieces in cross-section when you put them together, the two angles create a V shape and it runs the length of the weld. The grooved welds tend to make a stronger bond because they give the welder more penetration to start with.

Square-groove Weld or Butt Weld

This type of weld uses an electrical current or heat and pressure to fuse two pieces of metal together. If the joint is not properly prepared or designed, the weld will not penetrate correctly and the joint will be weaker than it is supposed to be.

U-groove Weld

The U Groove weld is very similar to the V groove with the exception that the sides of a groove are not straight. The U-groove weld is arched so when you put the pieces together the cross-section looks like a U. This is done to allow for even better penetration than the v-groove weld gets.

Bevel-groove Weld

The Bevel Groove weld starts with a straight angle on one of the pieces but not on the other. It is almost literally a half of a V groove weld. This weld is used to attach smaller pieces to bigger pieces and allows for better penetration into the peace being placed against the bigger piece.

Flare-V-groove Weld

The Flare-V–groove weld is used to attach two flanges together. You would position the flanges so that there is a V in the center. Then you want to run a weld down the valley in the V. This will effectively penetrate both sides sufficiently to bind them together.

J-groove Weld

The J-Groove weld is effectively half of a U Groove. If you look at the cross section of it, it will look like a J in shape. While the one section is left flat, the weld can penetrate into the surface of that section. It also has a pathway to penetrate into the other piece which allows for a little too strong of a bond in the weld joint.

Corner-flange Weld

This type of weld is used to attach flanges near the end of a piece of metal. They put the edge of the planes up to the edge of the metal and apply weld down the seam to hold it in place. With this type of weld,  you want to be sure that you’re using the appropriate equipment for the metal that you are welding. If you don’t, you will not get proper penetration and the weld will be weak.

Edge Weld

This type of weld is used to join two flat pieces of metal. These pieces can be different thicknesses or even different sizes as long as the edges that you are welding are compatible. This welding process lines up the edges and runs a bead of weld down the crease in the middle effectively attaching the two pieces. With this type of weld, it is also very important that you are using the proper equipment. Not getting proper penetration into the metal will cause a weak weld joint.

A Welder’s Injuries

Most people don’t think about how dangerous that welding can actually be. With all that heat and electricity flowing, welding can be a very serious operation. A few of the things that can happen are burns, shocks, electrocutions or flying debris. Most people know how to protect themselves against all of these problems because when you’re trained as a welder, the safety precautions are heavily drilled into you. The problem is that some beginners or novice users may not know the safety precautions or even have the proper equipment. Let’s take a look at it a couple of the things that can cause you a problem and possibly even send you to the hospital.

Depending on the severity of the burn, it is important that you clean the area with cold water. If you notice blisters or charring, then seek the help of a medical professional. However, if it is a mild burn you can treat the area with witch hazel or aloe vera to soothe the skin and aid with pain relief. If your eyes are affected, it may be what they call welders eye or arc eye. This condition is akin to a sunburn except for it is on the cornea in the eye. The cornea will typically heal itself within a few days. Shocks can also lead to burns depending upon the severity. Typically a shock is milder and will not lead to the more serious complications, however, if there are other complications from the shock, seek medical help immediately.

In Conclusion

Even though I have been welding for years and I knew that there were certain welds and joints that were stronger than others, I had never really thought about the differences. While writing this article, I have come across so much information on welds and joints that hopefully it will help me and you in the future. For right now though, make sure that you are using the proper welder with the right material. Follow some of the guidelines that I’ve outlined above and it should help you with designing and welding a proper weld joint. Once you get used to the process, it will become second nature to you.

Remember to keep a well stocked First Aid kit handy in case of injury. This should be an important piece of equipment for any shop. If there is any other information you are seeking, do a search of your own and see what you come up with. Just make sure that whatever you are working on, that you are safe doing it. For now, let’s get back to work and see what we can come with for our next project, happy welding.

Comments

  1. Thanks for sharing these all types of weld joints. I think there are many of other joints which are useful for welding when it is works in the Air Conditioning and also it helps to improve the energy.

  2. well, that was a lot of hard work. I had a lot of confusion about several issues, and you definitely cleared a lot.

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