The manufacturing process of steel road barrier is relatively complex, and the general flow is as follows:

1. Design: The initial stage of metal barrier manufacturing is barrier design. Designers use computer-aided design (CAD) software for the design.

2. Material Selection: After the design is completed, suitable barrier materials need to be selected. Commonly used materials include steel, aluminum, and iron.

3. Cutting: After purchasing materials, they need to be cut into the required sizes and shapes. This can be achieved using different cutting equipment, such as waterjet cutting machines, laser cutting machines, or plasma cutting machines.

4. Forming: The cut materials need to undergo bending, rolling, stamping, and other processing to finally achieve the required dimensions.

5. Welding: After the components are formed, they are joined together to form a complete barrier. Various welding methods are used, including arc welding and gas welding.

6. Finishing: After the barrier is welded, surface treatment is required. This may include sandblasting, painting, or powder coating to protect the metal from wind, rain, and corrosion, and to provide a decorative effect.

7. Quality Control: Metal fences undergo a quality control process before shipment to ensure they are sturdy and flawless.

Generally, the production of metal fences is a time-consuming process involving many different steps, requiring qualified personnel with specialized knowledge and appropriate facilities and equipment.