Stronger Steels Create Joining Challenges - From Design News

Interesting stuff here from one of my favorite sites:

Advanced high-strength steels are moving into the fast lane of automotive applications, thanks to the growing recognition that can help engineers reduce vehicle weight and improve crash worthiness. But the extra strength comes at a price: The strength gains that make these steels so desirable also compel designers and manufacturers to consider new welding techniques.

The reason why largely boils down to the pinchforce required to hold sheets together for in spot welding. Whereas a pinch of 400 pounds will accommodate a typical low-carbon steel, a pinch of 1,400 lbs or more would be needed for the higher strength steels. Dave Anderson, staff manager of the AISI Automotive Technical Panel, says that spot welding can successfully fabricate high-strength steel parts, but the process does require higher heat, pinch pressure, frequency and hold times. Shifting these parameters allows good welds to be made but often with weld cycles that differ from those found in industry today. Lincoln Electric Co., a global supplier of metal welding and cutting systems, is just one of the companies that has recognized the need for all-new welding systems for advanced high strength steels. Veteran Lincoln engineers, like Jim Nicklas, consumable research and development leader for gas metal arc welding (GMAW) products, are part of an ongoing research project to develop next-generation welding systems. Lincoln officials meet with original equipment manufacturers, like Ford Motor Co., and various Tier 1 companies on a weekly basis to explore new approaches to welding high-strength steel.

Read the entire article over at Design News. It's worth the time.