ERW (Electric Resistance Welded) pipe is a type of pipe that is created by welding the two ends of the pipe using electrical resistance.

It typically starts with cold-rolled steel pipe, and each end is heated with resistance to create the weld. The welding process involves compressing the ends of the pipe after they have been adequately heated.

Key features and characteristics of ERW pipes include:

1. Cost Efficiency: ERW welding is relatively cost-effective compared to some other welding methods. This makes it a high-productivity and cost-efficient process.

2. Versatile Applications: ERW pipes find applications in various industries. They are commonly used for basic transportation pipes, structural pipes, flange pipes, and more.

3. Standard Specifications: ERW pipes can be easily manufactured to standard specifications and sizes. This allows for the production of pipes with diverse specifications to meet specific industry or project requirements.

4. Corrosion Resistance and Durability: Depending on the materials used, ERW pipes can exhibit corrosion resistance and durability. This makes them suitable for use in diverse environments. 

5. Diversity of Use: ERW pipes are used in a variety of applications, including water supply,m gas pipelines, structural pipes, machinery, industrial pipes, precision machinery, and more.

ERW pipes are one of the widely used types of pipes due to their high productivity and cost-effectiveness. However, it's essential to consider that, depending on the environment of use or specific project requirements, other welding methods may be more suitable.