Bevel Weld: What, Diagram, Symbol, Process, Machine, Strength And Several Facts

This article discusses about the topic bevel weld. There are many types of welding processes as well as many types of welds that take place after welding.

These types depend on the configuration of metal sheets that need to be welded. In this article we shall discuss about one of many types of welds that is Bevel Weld. First we shall discuss about what is bevel weld, then we shall discuss in brief about other types of welds as well.

What is bevel weld?

A weld that fills the gap between two metals is called as bevel weld. Bevelling is done before we proceed with welding.

Bevelling is the process of removing some metal at the area where weld is going to take place. The weld is made after bevelling process is complete. The weld is formed in the valleys created after bevelling. Let us discuss more about bevel weld in further sections.

Bevel welding symbol

Different types of welds are shown with different symbols. Bevel weld can be represented by the following symbol

Bevel weld size

Size of bevel weld can be determined by measuring effective throat on groove. The size is written on the symbol itself.

The number written inside the parenthesis is the size of the bevel weld. For example if the number written is ¼ (3/8) then the size of weld is 3/8. If there is no number written inside the brackets then the size of weld can not be any lesser than groove depth.  These numbers are written right beside the groove symbol.

Bevel weld angle

Bevel angle is the angle made by the single plate which bevelled. Included angle is the total angle made by preparing both plates.

For a single bevel weld, the bevel angle is equal to the total angle between the plates or the included angle. This is not the case with single-v groove weld. The bevel angle is written between the groove in the bevel weld symbol.

Bevel weld vs fillet weld

The primary difference between both the welds is the configuration of the plates that are welded.

The table below shows the comparison between bevel weld and fillet weld.

Bevel weld strength

Strength of the welds is determined by looking at the value of stress under which the weld can fail. There are many types of stresses that can break the weld.

These stresses are mainly tensile stress, compressive stress and bending stress. The weld is weakest for the stress which has the least value. Generally the tensile strength of bevel weld is 0.3 times of the tensile strength of the material used for welding.

Bevel weld process

The bevel weld process includes the following steps

• Beveling– The sheets are beveled from the ends where the weld needs to be made. Bevelling means removing some material from the end of the plate where the weld needs to be made. Beveling is done so that the molten metal can seep inside the groove and make the bonds properly.
• Welding– Bevel weld can be made trough many techniques. TIG welding provides the strongest weld.

Types of weld

There are many types of welds made in industry. These welds have different characteristics and are made on the need basis.

The different types of welds are as follows-

• Fillet welds – Fillet welds are used to weld two plates kept at right angle. This weld is triangular in shape and the size of weld is calculated by measuring the throat length. This can be found using Pythagoras Theorem.
• Butt weld or Bevel weld – Bevel welds are used to weld plates from its ends. Some material is scraped out so that molten metal can seep inside the valley produced. This way a stronger bond is made.
• Spot weld – Spot weld is made to join the plates initially such that they do not move. Spot welds are generally made before the actual welding process is started. This is done to keep the plates intact.
• Edge weld – As the name suggests edge welds are made on the edges of plates. The weld takes place along the length of the edge. This way that side of the plate is sealed by the weld.
• Slot weld– The slot weld is made by using a hole on the plate. An elongated hole is made to weld two pieces.

Welding defects

No process is perfectly ideal, some defects are bound to be there. The goal is to make as less defects as possible.

Following are the list of defects that can occur in welding.

• Cracks – Cracks as we all know are sleek openings that happen when the material is stretched more than it can handle. It appears as if the material is torn off. Cracks will propagate if not sealed and it will break the weld if the crack propagates along the entire length.
• Overlap – This is a welding defect in which the molten metal used for welding runs on the surface of the base metal without actually fusing with it.
• Porosity – Porous means something which has pores and gases can pass through it. Porosity in welding means that the weld is left with some pores through which gases enter inside the weld making the weld weaker. For example Oxygen can corrode the metal.
• Undercut – In this defect, the thickness of weld metal is reduced due to which its strength is compromised.
• Slag inclusion – Slags are tiny particles that are non metallic. Slag act as impurities in the weld, because of slag inclusion the weld strength will be compromised.
• Incomplete fusion- Incomplete fusion means the weld metal has not completely bonded with the base metal. This can happen due to lower temperature while welding or insufficient current in the circuit.
• Incomplete penetration – Incomplete penetration happens in groove welds when the weld metal does not penetrate through the entire joint thickness.

Summary

In this article we studied in detail about bevel welds. We realised that beveling makes it easier for the molten metal to seep inside. This makes the bond stronger. The molten metal sits perfectly inside the cavity which when cooled makes a good joint between the plates.