Recycling of discarded steel plates requires leveling treatment to ensure that they can be reused. 

1. Warping and bending: This situation is usually caused by stress imbalance during steel plate processing. This problem requires leveling treatment to eliminate stress application.

2. Uneven and irregular shapes: This problem is usually caused by improper processing and operation. This issue requires leveling and trimming.

3. Groove wear and surface wear: This problem is usually caused by long-term use and friction wear of steel plates, and requires grinding and surface treatment.

The steps for leveling and recycling discarded steel plates are as follows:

1. Use a leveling machine to level the discarded steel plate. This can be done manually or mechanically.

2. Surface cleaning requires grinding and removal of rust or dirt on the surface of discarded steel plates.

3. Classify steel plates and recycle or sell them according to different types of steel plates.

4. Process and process the recycled steel plates to meet different usage needs.

In short, the leveling and recycling of waste steel plates can make a positive contribution to the environment and resources, while also reducing costs and improving economic benefits.