Trailers carry the largest loads of cargo on the highways and roads, and their steel chassis must be strong enough to handle these loads at all times, no matter what dangerous surprises the open road may have in store. One of the most critical parts of building a trailer is the welding of the joints, as this is a point on the trailer that is more vulnerable to stress than the main steel beams on the chassis.
These days, welding is done by a combination of automated and manual tasks. While there is a lot of helpful technology in the process that can enhance efficiency, it’s important that the technology be understood and properly applied by the fabrication team. Some things to look out for include stress concentrations, imperfections and residual stress, all of which can impact the fatigue resistance on your welding. Here are some welding joint tips for trailer builders.
Use proper filler metal
When welding, it’s important to know what type of filler metal will work best for the job. For starters, the strength of the filler should be matched to the strength of the base alloy. This is standard practice for all welding.
For trailer welding, however, it is possible to use an under-matched filler metal as long as there is a complete understanding of how the weld will be impacted in its location on the trailer. This is possible because welds on a trailer are often in a location that receives less overall stress than required to match the base alloy. Aluminum filler metal 5356 is often used in this instance with the 5XXX- and 6XXX-base aluminum used in trailer building.
Use the right heat input
One thing that can have a major impact on welding strength and overall toughness of the joint is heat input during welding. This is because the high strength of steel used in semi-trailers is particularly sensitive to this. In general, the maximum interpass temperature for high-impact and vulnerable welds is 212 degrees Fahrenheit. It is possible to use higher heat outputs when welding in lower stress areas.
Make a smooth weld
The goal when welding is always to have a smooth weld, and trailer building is no exception. Smooth welds should yield a smooth transition radius and round angle at the weld joint. Defects most likely to occur include undercuts, root defects, cold caps, lack of fusion and cracks.
The technique of inline weaving, or “shuffling,” is often used in trailer building. While it does look good, the technique doesn’t necessarily have an effect on the weld efficiency (when done correctly, of course). The weaving for this technique should be 3 to 4 mm in amplitude—anything larger than that may result in low spots in the weaving or reduce the length of the weld throat.
When you need a trailer built or repaired, it’s important to work with an experienced company that you can trust to get the job done right the first time. For all your trailer repair and welding needs, contact United Diesel Power – Truck Repair today.
Categorised in: Welding Services
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