Spring specialists in Sweden have recently made prototypes and performed tests on springs in a new, cost effective material that can withstand high temperatures.
A demand for compression springs to suit a large valve actuator application resulted in the need for some development and testing work for Swedish company, Lesjöfors. The springs would have to work in an environment of around 200-250 degrees Celsius with high demands of strength and relaxation resistance.
The traditional materials used for springs working in high temperature applications are made either in stainless steel or super alloys such as Inconel or Nimonic. The disadvantage is that these materials are very costly compared to tool steel and the strength is fairly low in larger dimensions. Apart from temperature, tool steel gave significant advantages.
To overcome this challenge, Lesjöfors manufactured ten springs in tool steel with a weight of about ten kilos each and hardened to 50 Rockwell C. The spring heat resistance was tested using a setting test to solid length at temperatures between 200 and 300 degrees Celsius to measure how well the springs’ characteristics withstood high temperatures.
With a very positive outcome to the tests, the company is now continuing its evaluations to obtain exactly the right steel for springs working in high temperature environments.