The Repeatability of Strength of Toughened and Strengthened Clear White Plate Glasses

摘要

At the time this work was carried out a large number of modifications to the toughening furnace had been carried out and a simple assessment was necessary of the variability which might be expected with toughened glasses processed in that furnace. For this assessment 300 specimens of clear white plate glass were toughened in six separate batches, the processing of the batches being at about 3 day intervals so that fresh setting up of the furnace was involved each time. Modules of rupture determinations were carried out on the toughened specimens and an overall co-efficient of variation of 6.9% was considerably lower than that obtained in earlier work. A similar study was carried out for strengthened glass. For both toughned and strengthened glass the batch to batch repeatability was rather low and a recommendation was made that efforts should be made to improve this. (Author)