Common Accidents on the Site of High-speed Steel Rolling and Measures (2)

5. What are the reasons for holding back the steel during rolling?

(1) Defects caused by the billet itself, such as inclusions, delamination, severe bubbles, etc., are rolled to half during the rolling process, causing cracking and holding the steel;

(2) When the speed of the certain intermediate rolling mill is set improperly, the steel rolling state is actually produced. The first half of the rolled piece is maintained by the front rolling mill to maintain tension rolling. When the tail of the rolled piece leaves the front rolling mill, the tension suddenly loses there, causing the holding back of steel;

(3) It is caused by the sudden increase or decrease of the speed of the motor of a rolling mill, which destroys the original continuous rolling relationship;

(4) Due to the sudden breakage of the roll or the severe damage of the guide in the previous passes, the cross-section of the rolled piece is changed and the steel is held.

Measures: ① Strengthen the picking of raw materials, strengthen the inspection of steel rolling, and take timely measures;

② Eliminate excessive tension;

③ Notify electrical treatment;

④ Regularly shut down to check the wear of the rolling guide to avoid holding back the steel.

6. Adjustment of the intermediate rolling mill unit: When adjusting the material type, you must first pay attention to the state of the stacking steel between the two rolling mills, and then adjust the ellipse material type. You must pay attention to whether the input splint is seriously worn.

7. Heavy iron hitting at the outlet of the rough and medium rolling mill:

(1). The front frame round hole material is too full or the input guide wears seriously (With severe scratches).

(2). The material type of this frame is inappropriate and too large.

(3). Change the exit guide.

8. Pre-finishing rolling mill: (1) 14 output is seriously ironed: the incoming material is too large, the amount of reduction is too large; the material shape is wide; the inner wall of the exit guide is not smooth, and the grinding is not good.

(2) 15 input is severely ironed: 14 outlets are worn and the torsion angle is not suitable; 15 inlet guide guard gaps are not suitable or severely worn and cannot support the steel;

(3) 15 input guide roller: the input guide is not installed correctly, and the incoming material hits the single-side guide roller when biting; the guide gap is not suitable, too tight; the guide roller is not cooled.

9. 17, 19 guide guard hit iron:

Measures: The guide gap is small, and press the 16, 18 material to re-find the tension.

10. Pre-finishing rolling leaving tail

Reasons: Tension before continuous finishing (continuous adjustment), the material shape is not good.

Measures: After pressing the material to the standard value, adjust the tension again; the delay time of the looper is not suitable; the height of the looper is not suitable.

11. 3# Shear steel pile

(1) Head pile steel

Reason: cutting head of 3# is too short, bring the head into 7 sets; 3# shear is without the head.

Measures: Lengthen the cutting head of 3# shear.

(2) Steel pile in the middle or tail

Reason: The pre-finishing rolling speed is set too high continuously.

Measures: adjustment to reduce pre-finishing 5 consecutive adjustments.

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