Karwon Composites supplies pultruded carbon fibre rods across standard and high modulus grades.
Send us the load case and the deflection you can accept, and we will recommend a grade rather than the most expensive one.
The grade of a carbon fibre rod refers to the fibre used to make it. T300 is a general-purpose standard-modulus fibre, T700 is a higher-strength fibre in the same family, and high-modulus grades such as M40J and M55J are far stiffer but more brittle and more expensive. The right grade comes down to whether your part needs strength, stiffness or a balance of the two.
What grade actually means
Two properties get confused often. Tensile strength is how much load the fibre takes before it breaks. Tensile modulus, or stiffness, is how much it resists stretching and bending under load. A high-strength fibre is not automatically a stiff one, and a very stiff fibre is often less tolerant of impact. Grade tells you where a fibre sits on that map. Tow size, such as 3K or 12K, is a separate matter and describes how many filaments are bundled together.
T300: general engineering
T300 is the dependable all-rounder. It offers solid mechanical properties at the lowest cost of the three, which makes it the sensible default for jigs, fixtures, general structural members and industrial parts where you do not need to chase the last few percent of performance.
T700: higher strength
T700 raises tensile strength and strain to failure while staying in the affordable standard-modulus family. It is tougher and more forgiving of impact, which is why it is the popular sweet spot for UAV arms, automotive components, sporting goods and load-bearing rods. If you are unsure between grades, T700 is usually the safe upgrade from T300.
High-modulus grades: maximum stiffness
M40J, M55J and similar high-modulus fibres are chosen when deflection is the enemy. They are much stiffer, so a rod holds its shape under load with minimal bending. That suits precision structures, optical and instrument mounts and high-end aerospace and motorsport parts.
The trade-off is real. High-modulus fibres are more brittle, with lower strain to failure, and they carry a premium price. Use them where stiffness is genuinely critical, not where toughness or cost efficiency matters more.
Matching grade to application
- UAV and drones: T700 for arms and booms that need strength and crash resilience, stepping up to high-modulus only where a long member must not flex.
- Marine: T300 or T700, with extra attention to the resin system and surface finish for a demanding environment.
- Structural and industrial: T300 as the baseline, T700 where loads climb.
Remember that the resin matters as well as the fibre. Standard, high-temperature and toughened epoxy systems behave differently under heat and impact, so the grade is only half the specification.
Sourcing carbon fibre rods in the UAE
Karwon supplies carbon fibre rods across standard and high-modulus grades, with short lead times, and documentation requirements agreed at quotation stage. Tell us your load and your deflection target and we can recommend a grade rather than leaving you to guess.
Start with an enquiry through our contact page.