Steel is a popular construction material because it’s flexible, durable, low-maintenance, corrosion-resistant, and sustainable. These properties make steel a highly attractive choice for both residential and industrial applications. However, compared to aluminum and other types of metal, steel doesn’t dissipate heat as effectively. Too much heat or improper welding practices can increase its susceptibility to corrosion.
To improve the quality of your welding results, here are some tips and tricks you can use:
- Preparing The Metal
Clean the surface of the metal before you start welding. Cleaning removes surface contaminants that may compromise the quality of the weld. Stainless steel, in particular, is susceptible to chromium buildup. A high chromium content can lead to excessive hardening—which, in turn, may increase the probability of cracking and distortion in the metal.
Hydrogen is another contaminant that can destroy welds. Unfortunately, it’s also present everywhere—in water, rust, dirt, and paint. If it gets left behind during the weld, it can compromise the weld. If the steel is crack-sensitive or if there’s residual stress, hydrogen may even cause the metal to crack hours or days after you finish welding.
To prepare the metal surface and get rid of these weld contaminants, use a wire brush to remove grease, paint, oil, and dirt. An acetone wipe may also help you remove tape residue, paint, and other coatings.
- Welding Steel To Other Metals
Some projects may require you to weld steel to other types of metal like aluminum. Is it possible to connect steel and aluminum? The answer is both yes and no. Welding aluminum to steel is extremely difficult, but it’s possible.
Aluminum’s melting point is 1220 degrees Fahrenheit, while steel’s melting point is 2498 degrees Fahrenheit. When the two metals are melted together, intermetallic compounds inevitably form. These compounds are crystallized structures that are very brittle. Any steel structure directly welded to an aluminum component will be fragile and prone to breakage at the weld bead.
To ensure structural integrity, you can do one of the two methods below:
- Using a bimetallic transition insert: As the name implies, a bimetallic insert is a material made of two types of metal. You weld the steel structure directly to the part of the insert made of steel and the aluminum structure into the part made of aluminum. However, this process can be quite expensive as it involves producing a custom-built insert.
- Dip coating: For small businesses looking to save some money, they’d usually opt for dip coating. This process involves dipping the steel structure into aluminum so the latter can coat it. The aluminum coating will prevent the formation of intermetallic compounds during the welding.
Although these two methods are the most common welding techniques, there are plenty of other ways you can use to connect two different types of metal. These include using mechanical fasteners, brazing, bonding, and aluminizing.
- Preventing Welds From Cracking Or Warping
Below are some of the common reasons welds crack or warp:
- Concave, hollow, or undersized beads were formed. The width of welds should exceed their height, and they should also always be curved outward or convex.
- The metal wasn’t adequately cleaned before the welding, causing hydrogen cracking.
- You didn’t preheat before the welding, especially when the steel structure or component has a high alloy or carbon content.
- You didn’t fill craters at the end of the welding process.
- You were welding stainless steel, but you failed to use low heat.
Make sure to avoid the causes enumerated above to reduce the chances of cracking or warping. As much as possible, you should also weld in short bursts of three to four seconds, giving the steel enough time to cool off.
- Controlling Angle, Power, And Heat
Ensure that your torch is at least 15-20 degrees into the direction you’re pushing the weld to ensure visibility and easy access to the filler material. Don’t use too much power right at the onset. Start with the lowest setting, or at least the power setting that you have no problem sustaining. This should give you enough leeway to produce the right puddle technique.
You should also pay attention to the color of the weld. If it’s golden or salmon-colored, then the heat you’re applying is just right. If it’s dark gray, you’re using too much heat, and there’s a possibility that the material might warp.
Use the tips above to create a strong and solid weld. At the same time, remember that the post-weld process is just as important as the steps you take before and during welding. Create a flat and smooth surface by using a welding hammer to chip off any slag. Next, use a grinding wheel and move it along the weld to press the beads down into the metal. And finally, wax or spray on some clear acrylic coating to prevent corrosion.