Proposal to enhance the heat soak test following EN-14179-1

O.Yousfi, Y.Brechet, P.Donnadieu, A.Kasper, F.Serruys

The alpha to beta phase transition of nickel sulphide was subject to extensive research in the last three years, using new laboratory methods. The specimens contained different proportions of sulphur (different “stoichiometry“) and different iron contamination. It was shown that, depending on composition and temperature, the transformation mechanisms are different. The nickel sulphide type with the slowest transformation rate causes late breaks in HST, and under bad conditions it might survive the test. The deciding finding is that the transformed volume fraction of just this type of nickel sulphide decreases when increasing the temperature above 280°C. Consequently, the conditions of the HST should be modified. The proposal is to limit its temperature to 280°C. This would enhance the safety of the “Heat-Soaked Thermally Toughened Glass”. Additionally, in comparison to today’s conditions, new HST conditions are proposed, mainly the reduction of the maximum temperature to 260±10°C. This new test allows to enhance (actually sufficient) safety and leads to a reduction of the soaking cost, and to less environment pollution due to reduced energy consumption of the HST procedure.

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The Authors

Oussama Yousfi SIMaP, Grenoble Institute of Technology, France • Born January 30^th , 1981 - Tunisia. • Graduated from the engineering school ENSEEG (ENS Electrochimie Electrométallurgie de Grenoble, France). • Currently Ph.D student in materials science at t... Read more