Case: Scana Steel Björneborg

Rapid assistance for Scana Steel Björneborg

When Scana Steel Björneborg ran into difficulties with their hardening process there was a sense of urgency. FUCHS helped out with a record speed oil analysis. It simplified the problem solving and limited the production stoppage at the facility in Värmland, Sweden.

The steel and foundry company, Scana Steel Björneborg, manufactures propeller shafts for customers in the shipping and offshore sectors. Other big markets for forged products – that can weigh nearly 78 tons – are the engineering, oil and gas industries. Several products are oil hardened and are submerged in an 80 cubic metres bath of hardening oil for several hours. But a short time ago the company was affected by overcooking in this process.

“When the 900 degree hot forged product was submerged, the oil suddenly started to foam and it sounded as if a jet aircraft was flying through the facility”, recalls Markus Larsson, Production Manager at Scana Steel Björneborg. “We had to stop immediately to see what was happening.”

Help with the analysis
Markus and his colleagues realised that water had entered the hardening bath and had caused the overcook. But at the same time they needed to carry out a complete analysis and to get a better idea of what the situation was with the hardening oil. An oil sample was sent to FUCHS later the same day.

“We engaged both the lab and our colleagues at R&D”, says Robert Wikman, application engineer at FUCHS. “The oil analysis was completed and the result emailed to Marcus at nine o’clock the same evening. We found water in the oil, but also something else that was strange.”

“The results showed that the viscosity was fine but that the flash point of the hardening oil was way too low, which reduces performance. To this picture one should add the fact that the flash point drops the more that a hardening oil is used, but then the viscosity is degraded at about the same pace – the oil “ages” quite simply. But in this case the link between viscosity and flash point did not correspond.”

“There appeared to be some kind of solvent in the oil that lowered the flash point”, says Robert Wikman. “We suggested that Scana Steel Björneborg should heat the hardening oil and in this way evaporate both the water and the solvent. In addition, we suggested using an additive for the oil because we noticed that several other characteristics had degraded.”

Tighter intervals
After the overcook the oil was temporarily pumped into a cistern. The bath was cleaned and searched for a water leak. When the hardening bath was refilled the contaminants were evaporated off. In addition, Scana Steel Björneborg received an extra delivery of hardening oil to replace the amount lost during the overcook.

“We never found a water leak, but suspect that it was condensation created in the facility that affected the hardening oil,” says Markus Larsson. All in all it took three weeks before oil hardening was in operation again. I am delighted with FUCHS’ efforts and we now send them oil analyses every month to be on the safe side.”