Versatile Empty Test Tubes Clear Glass Test Tube ODM 1-20ML

Durable and versatile Transparent Glass Tube Pure And Bright

Variety of glass materials, superior performance and good quality, not only can be used as decoration, but also durable and versatile. Glass partitions and car windows must be made of glass. Smooth and flat, pure and bright, all walks of life want it. Glass is now a more popular decoration material, and it is used in architectural interior decoration and outdoor glass curtain walls.

The purpose is to eliminate permanent stress and structural imbalance in glass products. Glass is a poor thermal conductor. After the product is formed, the surface layer and the inner layer will have a temperature difference during the cooling process. When the surface layer is solidified and the inner layer is viscous, the temperature difference exists but the stress relaxation does not exist. This temperature difference occurs when the surface layer is cooled to room temperature. , The inner layer continues to cool down and shrinks, which is hindered by the surface layer to produce tensile stress, and at the same time, the surface layer produces compressive stress, which is permanent. 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 . Because certain performance and functional glasses (such as optical glass, thermometer glass) are within the transition temperature range, the huge viscosity makes the structure particles move slowly, so that its performance cannot reach the equilibrium state consistent with the temperature, and it will balance slowly during use. Produce performance changes, so it must be kept at the annealing temperature for a sufficient time.