Being a welder, you might not be familiar with the term ‘burnback’ and the impact it has on the welding operation. But this is a crucial process that keeps welders and the worksites safe.
Burnback happens in GMAW (gas metal arc welding) when the electrode does not separate from the contact tip, leading to a short circuit. In other words, it is electric current discharging through the molten electrode material and the contact tip. According to statistics, burnback accounts for up to 45% of welding feedability problems and causes each hour welding down-time.
Let us look closely at what is burnback in welding and how it affects welding operations.
What is Burnback in Welding?
Burnback, also known as arc blow, is a welding phenomenon that can cause weld quality problems.It occurs when an arc is “sucked back” towards the weld pool during a welding process. This can result in porosity, undercut, lack of fusion, and other problems. Burnback can be caused by several factors, including current, magnetic fields, and polarity.
Understanding the Causes of Burnback
There are several causes of burnback in welding. These include:- Current: The arc can be “sucked back” towards the weld pool due to the current in the welding process. This can be caused by an imbalance in the voltage being used or a lack of control over the arc.
- Magnetic fields: This phenomenon occurs when there is an imbalance in the magnetic fields created by both electrodes. When this happens, the arc can be “attracted” back to the weld pool.
- Polarity: The polarity of the welding process can also cause burnback. If the welding process is set up incorrectly, the current can be reversed and cause the arc to move back towards the weld pool.
Reducing the Risk of Burnback
There are several steps that can be taken to reduce the risk of burnback in a welding operation.These include:
- Ensuring the correct voltage: This can help reduce the imbalance in the voltage and ensure that the arc is controlled.
- Controlling the magnet fields: Ensuring that the magnetic fields created by both electrodes is balanced.
- Checking the polarity: This will ensure that the current is not reversed, which can lead to burnback.