Heat Resistant Cylinder Neutral Glass Tube For Pharmaceutical Glass Vials

Used For Pharmaceutical Glass Vials Neutral Glass Tube

The size and distribution of the permanent stress caused by the thermal process in each part of the product will not be uniform, therefore, it will affect the strength of the glass product, and even break by itself due to stress concentration. Annealing can eliminate harmful tension inside the glass and prevent new stress from being generated. During annealing, heat the glass product or keep it to the annealing temperature after thermoforming, so that the original stress is relaxed and eliminated, and then slowly cooled to below the strain temperature. After the glass has completely entered the state of rigid body, the temperature difference between the inner and outer layers only produces temporary stress .

Purpose is to eliminate permanent stresses in the glass products and structural imbalances. Glass is a poor conductor of heat. After molding, the inner surface layer and the temperature difference in the cooling process there. When the inner surface layer solidification viscous, the temperature difference is present, but there is stress relaxation. When the surface layer cooled to room temperature, this temperature difference will appear. Inner continued cooling shrinkage, tensile stress hampered by the surface, while the surface compressive stress, is permanent.