10ml Glass Collection Tube

High-Durability Glass Equipment Transparent Glass Tube​

raw material

Including main raw materials and auxiliary raw materials. The former refers to the introduction of raw materials such as the oxides that form the network structure of the glass, the intermediate oxides and the oxides outside the network; the latter can accelerate the melting of the glass or make it obtain certain necessary properties.

main ingreadient

According to the nature of the introduced oxides, it is divided into acidic oxide raw materials, alkali metal oxide raw materials and alkaline earth metal oxide raw materials.
① Acidic oxide raw materials: raw materials such as SiO2, B2O3, Al2O3, etc. SiO2 is the skeleton of the glass structure in silicate glass. It gives the glass high strength, good chemical stability, heat resistance and low expansion, but it will increase the melting temperature of the glass and increase the viscosity. The cited raw materials of SiO2 are silica sand, sandstone, and quartzite. Adding B2O3 to the glass can reduce the thermal expansion of the glass, increase the refractive index, thermal shock resistance and chemical resistance, reduce the viscosity of the glass when the temperature is higher, and increase the viscosity of the glass when the temperature is lower. The cited raw material for B2O3 is borax or boric acid. Adding Al2O3 to the glass can reduce the tendency of glass to crystallize and enhance the chemical stability, increase the strength, and increase the viscosity of the glass. The cited raw materials are usually feldspar with K2O or Na2O and SiO2, and industrial alumina can also be used. Cangzhou Tianchang Craft Glass Products Factory specializes in the production of various types of high borosilicate glass tubes
② Alkali metal oxide raw materials: raw materials with Na2O and K2O. Adding Na2O and K2O to the glass can reduce the melting temperature and viscosity, but it will make the chemical stability of the glass worse. The cited raw materials are soda ash (Na2CO3) and potash (K2CO3).

It mainly includes the steps of batch preparation, melting, forming, annealing and post-processing.

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.