Lesjöfors, Sweden – One of the requests of firm compression springs for high temperature applications origins from the Lesjöfors sales office in the Netherlands, where the customer wanted to replace disc springs with compression springs in an actuator application for large valves. The compression springs would have to work in an environment of several hundred degrees with high demands of strength and relaxation resistance.
Internal discussions among group companies
To discuss challenges and possible solutions, the Dutch sales manager contacted Stefan Musslinder, the group’s technical manager and Per Davidsson, technical manager at the factory in Lesjöfors, specialized in the manufacture of large, industrial springs. They came up with the idea of producing springs in tool steel, which had never been done before.
Testing and measurements
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 the tool steel and the strength is fairly low in larger dimensions. The great advantages the team anticipated with tool steel led to a decision of starting prototype manufacturing and tests.
Stefan Musslinder comments on the development process:
“We manufactured ten springs in tool steel and did setting tests at temperatures between 200 and 300C. By doing so, we can measure how well the springs’ characteristics withstand high temperatures. The test results are very positive and we look forward to extended tests in longer time-series to investigate long-time relaxation resistance.”
Cost-effective and high quality springs
The potential for tool steel springs is rising and Lesjöfors in Åminnefors, Finland have received similar requests from Asian companies.
“Regularly, we get requests from customers who need springs working close to a furnace or in flow valve for steam for example. Compression springs in tool steel could be a great cost effective alternative in many high temperature applications”, says Per Davidsson.