DETROIT--A new process for making tubular metal structures from steel and aluminum is being developed by the National Institute of Standards and Technology (NIST) and a coalition of automotive manufacturers and suppliers. Called hot metal gas forming (HMGF), the process could soon replace conventional stamping and tubular hydroforming processes in the automotive industry.

Tubular metal structures offer significant advantages in automobile design. Compared with conventional stamp-and-weld assemblies, tubular metal structures are stronger and use metal more efficiently. They reduce vehicle weight by 5 to 15 percent, and they cost 5 to 10 percent less. They perform better in crash tests, they have better vibration and noise characteristics, and they are more dimensionally stable.

The major drawback of tubular metal structures is that the technology for making them--called hydroforming--has high capital costs, is relatively slow, and imposes significant design restrictions.

HMGF promises to overcome these limitations, cutting processing costs by half and reducing the time to build new tooling by 40 percent. HMGF derives from superplastic forming and hot-blow forming, which are used in the aerospace industry to form aluminum and titanium structures. These technologies are not used in the auto industry because they are slow, expensive and ill-suited to the carbon structure steels used in cars.

Working with a $3 million grant from NIST, the coalition is

  • developing materials and techniques to create special HMGF dies. The dies are coated with a graded ceramic surface to withstand the stresses of the forming process.
  • developing improved steel alloy formulations to work with the HMGF process.
  • developing an intelligent process control technology based on feedback from sensors in the dies.
  • building prototype production systems capable of processing a 300-piece run at a cycle time of 15 seconds per part.
Members of the coalition include Alcoa, Atlas Technologies Inc., Daimler-Chrysler Corp., Erie Press Systems, Ford Motor Co., Lamb Technicon Body & Assembly Systems, and Tower Automotive.

For more information, call Lamb Technicon at 810-749-2351 or visit