Summarize the chain development trend according to the current chain development.

     In terms of raw material transformation, it has the following performance:

1. The annealing of raw materials began to eliminate the backward operation mode of coal smelting furnace, and annealed in a bell furnace protected by nitrogen (or nitrogen-hydrogen mixture) to make the hardness of the material uniform and avoid surface decarburization.

2. The continuous rolling and continuous drawing technologies are becoming mature, and the line speed has been increased from 0.25 m/s to 1--4 m/s.

     3. Pollution treatment technologies such as pickling are also becoming mature.