Glass; unworked, in tubes, of fused quartz or other fused silica

HS v2017 Code: 700231

About glass; unworked, in tubes, of fused quartz or other fused silica

HS code 700231 covers the import and export of unworked glass tubes made from fused quartz or other fused silica. This material is highly valued for its exceptional heat resistance, chemical stability, and optical properties, making it a crucial component in a wide range of industries, from electronics and telecommunications to scientific research and high-temperature applications.

Production process

The production of fused quartz or silica glass tubes involves a multi-step process. First, high-purity quartz or silica sand is melted at extremely high temperatures, typically around 2,000°C. The molten material is then drawn into long, continuous tubes using specialized equipment. The tubes are carefully annealed to relieve internal stresses and ensure dimensional stability before being inspected and packaged for distribution.

Production inputs

The primary raw material for this industry is high-purity quartz or silica sand. Manufacturers also require specialized equipment, such as furnaces, drawing machines, and annealing ovens, to facilitate the production process. Additionally, energy sources, such as electricity or natural gas, are essential for maintaining the high temperatures required during melting and drawing.

Production outputs

The glass tubes produced under HS code 700231 are used in a variety of applications, including 701931 Glassware for laboratory, hygienic or pharmaceutical purposes, 854011 Cathode-ray television picture tubes; including video monitor cathode-ray tubes, and 854020 Television camera tubes; image converters and intensifiers; other photo-cathode tubes. These tubes are also used in the production of 701990 Other articles of glass, n.e.s., such as laboratory equipment, scientific instruments, and specialized lighting components.

Revisions to 700231

Classification codes are adjusted frequently. The code may have been revised or replaced between system versions. The table below shows the history (newest to oldest) of the code 700231. The most recent 1 version of this code (700231) is in the HS v2022 system:

This page shows a legacy version of code 700231 ( HS v2017).

Family tree for glass; unworked, in tubes, of fused quartz or other fused silica

    graph LR
    A["<a href='/classifications/hs/v2017/70'>70: Glass and glassware</a>"]
A --> B["<a href='/classifications/hs/v2017/7002'>7002: Glass in balls (other than microspheres of heading no. 7018), rods or tubes, unworked</a>"]
B --> C["<a href='/classifications/hs/v2017/700231'>700231: Glass; unworked, in tubes, of fused quartz or other fused silica</a>"]

    B --> D["<a href='/classifications/hs/v2017/700210'>700210: Glass; unworked, in balls (other than microspheres of heading no. 7018)</a>"]
B --> E["<a href='/classifications/hs/v2017/700220'>700220: Glass; unworked, in rods</a>"]
B --> F["<a href='/classifications/hs/v2017/700232'>700232: Glass; unworked, tubes, of glass having a linear coefficient of expansion not exceeding 5 x 10 (to the minus 6), (or 0.000005) per Kelvin within a temperature range of 0-300 degrees C</a>"]
B --> G["<a href='/classifications/hs/v2017/700239'>700239: Glass; unworked, in tubes, other than of glass having a linear coefficient of expansion not exceeding 5 x 10 (to the minus 6, (or 0.000005) ) per Kelvin within a temperature range of 0-300 degrees C, not fused quartz or other fused silica</a>"]

    

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