Fiberglass, in fact, has nothing to do with steel. Steel is just an adjective, meaning it's as strong as steel. Glass has always given people the impression of being fragile and easily broken. How could it become as strong as steel?
In reinforced concrete, steel is the "bone" and concrete is the "flesh". Fiberglass is also somewhat similar to reinforced concrete: people melt glass and pull it into fine filaments. Glass filaments are very elastic and can be spun into yarn and woven into cloth. By pressing layers of glass cloth or glass fibers together and adding styrene, curing agent, etc. to unsaturated polyester resin, it is cured and molded, resulting in fiberglass (also known as glass-reinforced plastic) with plastic as the "flesh" and glass filaments as the "bone". Commonly used unsaturated polyester resins include phenolic resin, epoxy resin, and silicone resin.
Reinforced concrete combines the excellent plasticity of steel and the strong compression resistance of concrete. Fiberglass follows the same principle. Glass fibers have high strength, low deformation, corrosion resistance, non-flammability, and good electrical insulation, while resins have good plasticity. The composite material made from glass fibers and resins is an excellent composite material.
The mechanical strength of fiberglass can be compared with that of steel, but it's only 1/4 as heavy as steel of the same volume, making it very lightweight. Fiberglass doesn't rust and doesn't conduct electricity, which is something steel can't match.
Fiberglass can be used to make car bodies, small boat hulls, train carriages, building materials, etc. It's light, beautiful, and strong. A fiberglass car body weighs only over 150 kilograms, which can be lifted by two people. As for bicycles with fiberglass bodies, they're even lighter, carried in the hand like a small suitcase. Fiberglass boats don't rust or decay, are lighter than wooden boats, and the boat body can be made into a whole piece without splicing. If there's a break in the car or boat body, just apply some paste-like adhesive resin around it and stick pieces of glass cloth on it like sticking stamps on an envelope. Surf lifesaving boards made of fiberglass are very lightweight.