{"id":168,"date":"2026-09-26T02:27:54","date_gmt":"2026-09-26T02:27:54","guid":{"rendered":"https:\/\/lxcomposites.com\/carbon-fiber-types-classification\/"},"modified":"2026-10-19T15:44:17","modified_gmt":"2026-10-19T15:44:17","slug":"carbon-fiber-types-classification","status":"publish","type":"post","link":"https:\/\/lxcomposites.com\/zh_cn\/carbon-fiber-types-classification\/","title":{"rendered":"Carbon Fiber Types & Classification \u2013 Precursor, Tow Size, Grade and Sizing"},"content":{"rendered":"
\"Carbon
Carbon fiber structure detail<\/figcaption><\/figure>\n

Carbon fiber is not one material \u2013 it is a family of materials with very different properties and price points. Understanding the main classification axes helps you avoid over-specifying (paying for aerospace grade you do not need) or under-specifying (getting a part that fails). This article explains how carbon fiber is classified in the industry.<\/p>\n

1. Classification by precursor material<\/h2>\n

PAN-based carbon fiber (polyacrylonitrile): accounts for over 90% of all carbon fiber used today. Best balance of strength, modulus and cost; the default choice for fabrics, prepregs and structural parts.<\/p>\n

Pitch-based carbon fiber: made from petroleum\/coal pitch. Very high modulus and thermal conductivity; used in aerospace thermal management, satellite structures, and specialty tooling \u2013 much more expensive.<\/p>\n

Rayon-based (cellulose) carbon fiber: mostly historical; used in niche ablative and insulation applications.<\/p>\n

2. Classification by tow size (filament count)<\/h2>\n

Tow size is the number of filaments in one bundle, written as 1K, 3K, 6K, 12K, 24K and up to 480K for industrial grades:<\/p>\n

Small tow (1K\u201312K): finer surface, easier weaving, premium quality and price. Typical for aerospace-grade fabrics, cosmetic parts and prepregs.<\/p>\n

Large tow (24K\u2013480K, “industrial tow”): lower cost per kg, coarser texture, used in wind blades, pultrusion, automotive structural parts and chopped fiber for molding compounds.<\/p>\n

Note: modern “large tow” technology has narrowed the gap \u2013 24K\/48K tow is now used in many high-volume automotive parts where 12K was standard a decade ago.<\/p>\n

3. Classification by mechanical grade (strength & modulus)<\/h2>\n

Industry grade terminology is usually benchmarked against the well-known Toray\u00ae series (used globally as a reference, not as our own product claim). LX Composites supplies equivalent-grade fibers:<\/p>\n

Standard modulus \/ T300-grade: tensile strength ~3.5 GPa, modulus ~230 GPa. General-purpose, low cost, fine for most industrial, sports and consumer parts.<\/p>\n

Intermediate modulus-high strength \/ T700-grade: strength ~4.9 GPa, modulus ~230 GPa. The workhorse of the industry \u2013 used in most structural composites, aerospace secondary structures, automotive and sporting goods.<\/p>\n

High strength \/ T800-grade: strength ~5.9 GPa, modulus ~294 GPa. For high-performance aerospace and automotive primary structures.<\/p>\n

High modulus \/ T1100 or M-grade: modulus up to 400 GPa and beyond, lower strain-to-failure. Used in spacecraft, high-end sports (golf shafts, archery), and stiffness-critical applications.<\/p>\n

Practical guidance: most buyers only need T700-grade performance. Specify the tensile strength, tensile modulus and strain at failure in your technical datasheet rather than relying on brand names.<\/p>\n

4. Classification by surface treatment (sizing)<\/h2>\n

Sized (sizing applied): a thin polymer coating on the fiber surface improves bonding with a specific resin (epoxy, nylon, PEEK) and reduces fiber damage during weaving. Always match the sizing to your resin system.<\/p>\n

Unsized: used in specialty processes or where sizing interferes (e.g. some thermoplastic processes); handle with care because fiber damage increases.<\/p>\n

Oxidized\/surface-treated: controlled surface chemistry to improve interfacial adhesion for structural applications.<\/p>\n

5. Classification by product form<\/h2>\n

Continuous tow\/roving: the base product for filament winding, pultrusion, weaving.<\/p>\n

Fabric (woven, unidirectional, multiaxial): for lay-up, infusion, prepreg.<\/p>\n

Prepreg: fiber + resin, ready to mold.<\/p>\n

Chopped fiber \/ milled fiber: for injection molding compounds and additive manufacturing.<\/p>\n

Short fiber thermoplastic pellets: compounded with PP, PA, PEEK etc. for injection molding.<\/p>\n

6. How to specify carbon fiber with your supplier<\/h2>\n

Define: precursor (PAN), tow size (e.g. 12K), grade\/performance (strength and modulus targets, e.g. \u22654.9 GPa \/ \u2265230 GPa), sizing (e.g. epoxy-compatible), and form (tow, fabric, prepreg, chopped).<\/p>\n

Ask for the datasheet and, for critical parts, request a certificate of analysis per batch.<\/p>\n

Compare price per kg of PERFORMANCE (strength\/modulus per kg), not price per kg of fiber alone.<\/p>\n

7. How to order from LX Composites<\/h2>\n

LX Composites supplies carbon fiber woven fabrics, unidirectional fabrics, chopped fiber, and thermoset\/thermoplastic prepregs with equivalent T300\/T700\/T800-grade fibers and custom sizing options. Send us your application and target performance, and we will recommend the most cost-effective grade. Contact us for samples and data sheets.<\/p>\n

Related Reading<\/h2>\n