4　Finishing Process of Plate

4.1　Finishing Process of Extra-Heavy Plate

4.1.1　The finishing process procedure of extra-heavy plate should include cooling after rolling，surface inspection，grinding，head cutting，tail cutting，trimming，cut-to-length and sample cutting，internal defect detection，flattening，marking，finished product storage and other process steps.

4.1.2　Heat treatment and cut-to-length，sampling，straightening and so on after heat treatment may be done for product varieties and sizes with special requirements，and some products may also be demagnetized.

4.1.3　Incoming material should be steel plate rolled by plate mill.

4.1.4　Production process and equipment shall meet the following requirements:

1　Dedicated cooling bed or table should be provided on production line，disk or walking type cooling bed is preferred.

2　Slow cooling mode and slow cooling time shall be determined according to steel grade，size，chemical composition，smelting and casting process conditions and other factors.

3　Surface inspection of cooled extra-heavy plate shall be done first，then the plate shall be turned over by turn-over machine and defect shall be treated if any.

4　Plate should be cut by the way of automatic flame cutting or plasma cutting.Plasma cutting shall be provided with dust collecting device or the cutting shall be done underwater.

5　Plate with internal quality requirement shall be detected by ultrasonic testing device for detecting internal defect.

6　Steel plate should be flattened by flattener.Carry-over table should be provided before and after the flattener and the flattener press head shall be able to move laterally.

7　Steel plate surface shall be marked.

8　The overall dimensions，upper and lower surfaces，edges，straightness and marking quality of extraheavy plate shall be checked according to technical requirements during its finishing process.

4.1.5　The working system and annual working time of finishing line shall be determined according to the designed output，product varieties，sizes and production process，etc.，which may be different from those of the rolling line.

4.1.6　Process layout shall meet the following requirements:

1　Proper equipment configuration，compact layout，smooth and short process flow and proper buffer storage shall be designed according to such characteristics as diversified product varieties and sizes，small production lot，crossing route of finishing process routes and long processing cycle.

2　The operation of extra-heavy plate finishing should be concentrated in the specific area in plate mill workshop.

3　Plate slow cooling and piling yard shall be provided.