Peter SOMMER

Dr. Sommer Werkstofftechnik GmbH

Hellenthalstraße 2 – D-47661 Issum

-Vocational training as a materials tester at Edelstahlwerk Witten

-Studied materials science at the TU Berlin, graduating as a Dipl.-Ing.

-Five years as a research assistant in the Department of Mechanical Engineering/Materials Engineering at the Mercator University Duisburg with doctorate (Dr.-Ing.)

-Seven years Technical Managing Director at Schwing Verfahrenstechnik GmbH (Fluidized bed technology)

October 1988: Foundation of Dr. Sommer Werkstofftechnik GmbH

-2013: Buyout of the former metallography and strength testing laboratory of Böhler Edelstahl, Düsseldorf

-2018: Buyout of the former materials testing laboratory of Schmolz &

Bickenbach, Neuss Auditor for the heat treatment process with 130 audits in the USA, Brazil, China, India, England, Spain, Italy, Finland, France, Austria and Germany

-2012 – 2022: Lectureship at Rhine-Waal University of Applied Sciences, Kleve for the elective subject "Materials Testing and Failure Analysis"

-2018: Appointment as honorary professor

-2018 – 2021: Lectureship at the University of Duisburg for the obligatory subject Materials Science of steels

-2012 Burgdorf award winner

-2015 University Award winner from Rhine-Waal University of Applied Sciences in Kleve

-2012 – 2019: Chairman of the DIN Standards Committee "Requirements for heat treatment plants"

-2017 – 2021: Chairman of the VDI working group "Materials

Technology" of the VDI Lower Rhine district

-2016 – 2022: Member of the Board of Directors of the Heat Treatment and Materials Technology Working Group

Faults Before, During and After Heat Treatment of Steels

Numerous components and the majority of tools obtain their performance properties through specific heat treatment. This requires material-dependent temperature-time-atmosphere cycles, which can lead to very high stresses in the workpieces. Deviations from the best possible selection of heat treatment parameters can prevent further use of these workpieces. Excessive distortion, cracking and undesirable changes in edge composition are just some of the possible heat treatment errors.

However, it is often not realized that even with proper heat treatment, defects can occur that are latent in the workpiece and come to the surface due to the specific heat treatment conditions. For example;

Residual stresses from mechanical processing are released by exceeding the recrystallization temperature. If these residual stresses are unevenly found in the workpiece, the results of the release of these residual stresses will also vary.

- The steels themselves can show a wide variety of imperfections or defects, which also have an effect on the heat treatment.

- Machining in the hard condition following heat treatment requires high precision to avoid cracking or changes in properties. Finally, improper operating conditions can lead to damage when the workpieces are used.

This short list makes it clear that faults can occur before, during and after heat treatment. The possible causes are almost unlimited, especially as several influencing factors can overlap.

The presentation makes it clear that defects in heat-treated components are not always due to a heat treatment fault.