As we all know, carbon fiber is a tow material, according to the size of the tow within the fiber, carbon fiber can be divided into small tow carbon fiber (number of tows ≤ 24K) and large tow carbon fiber (number of tows > 24K), in which the K represents a thousand monofilaments in the tow, for example, the 3K specification carbon fiber means that there are 3,000 monofilaments in each tow, and the 12K carbon fiber means that there are 12, 000 monofilaments in each tow. For example, 3K carbon fiber means 3,000 monofilaments per tow, while 12K carbon fiber means 12,000 monofilaments per tow.
Depending on the precursor source, the diameter of each monofilament in the carbon fiber tow varies, for example, the monofilament diameter of pitch-based carbon fibers is more than 10 μm, while the monofilament diameter of PAN-based carbon fibers is 5-8 μm, with a carbon content of about 95%; for the high-modulus PAN-based carbon fibers, the diameter of the monofilaments can be as low as 4.5 μm, with a high carbon content of more than 99%.
In this paper, the main features and typical applications of carbon fibers of different specifications such as 1K, 2K, 3K, 6K...... are briefly introduced.
1K carbon fiber
1K carbon fiber: it is a very rare fiber, it is lighter than other fibers and very expensive, mostly used for finishing surfaces, most of the companies can't even calculate the stress within the weave, and its approximate line density is 66g/ 1000m.
2K Carbon Fiber
2K Carbon Fiber: It is the rarest carbon fiber on the market and is currently made by no more than 2 carbon fiber producers worldwide. It gives carbon fiber panels perfect stiffness, low weight and good vertical compliance (comfort), but is also very expensive.
3K Carbon Fiber
3K carbon fiber: the most popular and common type of carbon fiber. It gives a classic carbon fiber look to carbon fiber boards. 3K is the workhorse of carbon fiber, it is lightweight, relatively strong and easy to manufacture. 3K has a higher elongation at break and ultimate strength than 6K, 9K or 12K.
Because 3K fiber has smaller tows, it can be used to weave thinner fabrics than 12K and to wind thin tubes with fine filaments. It is used primarily in aerospace, industry, construction, sports, and recreational goods, and has a typical wire density of 198 g/1000m.
6K Carbon Fiber
6K Carbon Fiber: Using 6K is easier to infiltrate and drapes better than 12K. It is used in aerospace, construction reinforcement, automobile modification, etc. The linear density is 396 g/1000m.
12K Carbon Fiber
12K Carbon Fiber: Most carbon fiber manufacturers are likely to use 12K to reduce costs because 12K fabrics are cheaper than other K-count fabrics. 12K is easier to fabricate, less work, and cheaper. It has higher tensile strength, but is not suitable for some structures in bicycles. It is mainly used for military, industrial robotics and scientific equipment, and has a linear density of 800g/1000m.
24K and 48K Carbon Fiber
24K and 48K Carbon Fiber: Industrial grade carbon fiber is predominantly used, so it is mainly used in the manufacture of filters, insulation, workwear sewing, soft furniture and mattress manufacturing.
