Researchers model new steel tubing for nuclear weapons

Researchers at Sandia National Laboratories recently developed a computer model to improve stainless steel tubing suitable for use in nuclear weapons with the help of the National Nuclear Securirity Administration's Kansas City Plant.

The study came about when researchers realized the steel needed to construct nuclear weapons can became brittle due to its rigidity. Thus, the newly developed modeling softens the steel tubing needed for the weapons, while keeping the strong structure of steel.

This discovery is part of a bigger program for nuclear weapon development, called Predicting Performance Margins. Sandia researchers study the ways microstructures affect the properties of the larger structure of materials through this program.

Sandia's experiments had important implications for softening methods, which include recovery and recrystallizations. These methods first look at the microstructure of heated material, then measure its durability and strength after each heat treatment.

"It was important to model both softening mechanisms because we were seeing microstructures that contained no new recrystallized grains, but which had changed properties from the initial deformed material," Sandia National Laboratories researcher Lisa Deibler said. "By failing to include the effects of recovery, our model couldn't predict why the properties weren't the same as the initial deformed material. Adding in recovery allowed us to account for the changed properties in microstructures with no recrystallization."

Upcoming efforts will explore the development of laser welding, resistance welding and gas tungsten arc welding. The thermal rates vary per method and further research is necessary.