For decades, auto manufacturers have used mild steel in their designs. It’s easily shaped into whatever form is needed. And it’s less expensive than many other metals. But today, car companies are turning to an even stronger, lighter option—high-strength steel.
As the name suggests, high-strength steel is stronger than mild steel, making cars safer. This is especially true of areas of the car that keep the frame from intruding into a passenger during a collision. High-strength steel also gives engineers the ability to shed hundreds of pounds from their finished products for better gas mileage. And as manufacturers work towards meeting the new standards that require vehicles to get at least 35 mpg by the year 2020, you can expect to see even more high-strength steel in their designs.
High-strength steel isn’t just something to think about for the future, though. You need to know how to work with it now, because it has a different heat tolerance than mild steel. And if you use the same method and spot welder on high-strength steel that you use on mild steel, your repairs could actually make a vehicle less safe if it’s in another collision.
There are four things main things that your techs need to understand before they fire up the spot welder and get to work on repairs that involve high-strength steel:
- Type of steel involved. Manufacturers use several kinds of high-strength steel, including Dual Phase (DP) Steel, Transformation-Induced Plasticity (TRIP) Steel, Complex Phase (CP) Steel and Martensitic (MS) Steel. Each has its own unique properties and methods that are crucial in making repairs that safeguard passengers in the event of another collision.
- Type of collision. Different high-strength steels react differently upon impact. Techs need to know how each of those materials behave in order to predict all of the locations and kinds of damage done.
- The right welding equipment. High-strength steel requires resistance spot welding, MIG welding and brazing processes much more than mild steel. The right equipment—like the Chief MI200T spot welder—and the proper training are both absolute necessities.
- The right welding processes. The recommended joint configurations, riveting methods, transfer methods, heat applications, filler materials, wire speeds and voltage settings are all much different than those a tech would use on mild steel.
Without the right knowledge, spot welding equipment and training, your techs could be getting cars out of your shop on schedule—but the strength of their repairs may not hold up in another collision. The potential for serious injury in these situations is high. And the damage it does to your reputation and insurance premiums could last for years.
Get to know high-strength steel and all of the factors and possibilities involved in its repair, because it’s not going anywhere. In fact, you’ll see more and more of it in the coming years.