What's the difference between a semicircular head screw and a large flat head screw?

The difference between a semi-circular head screw and a large flat head screw is actually the difference between the screw heads. Compared with the head of the semi-circular head screw, the head of the large flat head screw is larger and the stress area is larger, so the product is not easy to be damaged at the joint of the screw. As shown in the figure:

Screw is a tool to tighten instruments and parts step by step by using the physical and mathematical principles of circular rotation and friction of the inclined plane of an object. Screw is a general term for fasteners. Screws are indispensable industrial necessities in daily life, such as tiny screws used in cameras, glasses, clocks and watches, electronic products, etc. Universal screws for TV sets, electrical products, musical instruments, furniture, etc. As for projects, buildings and bridges, large screws and nuts are used; Transportation equipment, airplanes, trams, cars, etc. There are both large and small screws. Screw plays an important role in industry. As long as there is industry on the earth, the role of screws will always be important. Screw is the same invention in people's production and life for thousands of years. According to the application field, it is the first invention of mankind.