TMT steel bars come with unique properties. The problem is that these properties make it challenging to weld TMT steel bars.
Welding them requires special attention and techniques to ensure structural integrity and safety.
In this blog, we’ll discuss the challenges associated with welding TMT steel bars and provide some valuable tips for achieving successful welds.
Let’s start without further ado.
Challenges in Welding TMT Steel Bars
High Carbon Content
TMT bars typically have a higher carbon content compared to mild steel.
This makes them prone to cracking during welding if not properly managed.
So, that’s a challenge.
Exposure to Heat
Heat gets generated when you weld TMT bars and this can affect the microstructure of TMT bars.
What does this mean?
Well, this leads to changes in their mechanical properties, such as hardness and toughness.
TMT steel bars are all about their strength.
However, improperly welding can make their welded joints brittle, compromising the overall strength of the structure.
TMT steel bars come bundled with surface contaminants like rust, oil, or mill scale. This stuff must be removed or else it can adversely affect the quality of the weld.
So, cleaning the bars before welding is imperative.
Differential Cooling Rates
TMT bars have varying cooling rates due to their different core and surface temperatures, which can lead to distortion and residual stresses in the welded joint.
But, don’t worry. It’s perfectly possible to weld TMT steel bars.
Tips for Welding TMT Steel Bars
Preparation is Key
Clean the surface of TMT bars thoroughly to remove any contaminants using a wire brush, sandpaper, or solvent cleaning.
Preheat if Necessary
Preheating the TMT bars before welding can help reduce the risk of cracking by minimizing the temperature differential between the core and the surface.
Controlled Heat Input
Use the appropriate welding parameters, such as current, voltage, and travel speed, to control the heat input and minimize the The Heat Affected Zone (HAZ).
Use Low-Hydrogen Electrodes
Low hydrogen electrodes (e.g., AWS E7018) are recommended for welding TMT bars as they produce welds with lower hydrogen content, reducing the risk of cracking.
Peening and Post-weld Heat Treatment
Make sure to peen the welded joint or apply post-weld heat treatment after welding.
This can help relieve residual stresses and improve the overall toughness of the weld.
Avoid excessive heat input or prolonged welding times, as this can lead to over-tempering of the TMT bars and degradation of their mechanical properties.
Inspect Welds Carefully
After welding, inspect the welds visually and using non-destructive testing methods like ultrasonic testing to ensure quality and integrity.
Welding TMT steel bars requires careful consideration of their unique properties and challenges. You can follow the tips outlined in this blog and exercise proper welding techniques to ensure strong and reliable welds in TMT structures. If you are still not confident, consult a welding expert to ensure safety and precision.