JPS5886903A - Cold rolling method for obtaining steel plate of high cleanness - Google Patents

Abstract

PURPOSE:To produce a cold rolled steel plate of high cleanness by spraying detergent oil, hot water or high pressure washing water to a steel plate to be rolled on the inlet side of the stand in the first stage of tandem cold rolling mill trains. CONSTITUTION:In tandem cold rolling mill trains, nozzles 6 for injecting detergent oil, hot water or high pressure washing water onto the top and bottom surfaces of a steel plate S to be rolled are provided on the inlet side of the No.1 stand. The detergent oil, etc. are injected from the nozzles 6 to wash the iron smudge stuck on the plate S beforehand. Thereafter, rolling mill lubricants are used in the same manner as before from the outlet side of the stand 1 up to the inlet side of the No.4 stand and detergent oil or rolling mill lubricatns of low concns. are used in the same manner as in the prior art on the inlet side of the No.5 stand 5. The cleaned detergent oil, hot water or washing water used for washing on the inlet side of the stand 1 is cyclically used after filtration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention j relates to a cold rolling method for obtaining a highly clean steel plate.

The iron smut remaining in the cold-rolled steel sheet catalyzes the polymerization reaction of the rolling oil remaining in the cold-rolled steel sheet and produces iron soap during annealing of the cold-rolled steel sheet, thereby improving the cleanliness of the cold-rolled steel sheet. significantly decreases

Therefore, hot water (40 to 60°C) has been used in the first stand of a tandem cold rolling mill row for the purpose of blocking off the pickling precoat oil, and in the final stand for cleaning the steel plate surface. Detergent oil or low-concentration rolling oil (1 g or less) is used to roll iron smuts on steel plates at the intermediate stage stand for the purpose of rolling lubrication and cooling, and using rolling oil with excellent annealing properties. In the cold rolling method to remove iron or in the final stand, detergent oil or low-concentration rolling oil is used in the same way as above, and in other stands, rolling oil is used in the same way as above to remove iron on the steel plate. A cold rolling method is used to remove smudges.

It is rare.

For that purpose, the present inventors investigated the adhesion status of iron smear on the steel plate between each stand in the conventional cold rolling method described above, and found that the A considerable amount of iron smear had already adhered to the rolled steel sheet, and the amount was several times the amount of iron smudge remaining on the cold rolled steel sheet at the exit of the 11+1IIL5 stand.

It was also found that the iron smear adhering to the rolled steel plate on the entry side of the first stand was reduced in each stand during rolling, and the degree of reduction was found to be correlated with the rolling reduction rate.

The present invention has been made based on the knowledge obtained from the above investigation, and an example of its implementation will be described below with reference to FIG.

As shown in FIG. 2, for example, lll&lL1 stand 1,
Stand 2 Stand 2, Stand 3 Stand 3, Stand 4 Stand 4-N
Detergent oil (5 to 90%) or hot water (70 to 90%
℃, to 5) or high pressure washing water of 101 or higher (10 to 5
A nozzle 6 for spraying water (0°C) is provided, and iron smudges adhering to the rolled steel plate S are washed in advance with detergent oil, hot water, or high-pressure washing water sprayed from the nozzle 6.

As before, rolling oil is used from the exit side of NQ1 stand 1 to the entry side of stand 4, and detergent oil or low concentration rolling oil is used on the inlet side of N15 stand 5 as before. is used.

In addition, the washed detergent oil, hot water, or washing water used on the inlet side of the stand 1 is filtered to remove iron smudges and other impurities, and then recycled.

Each stand 1゜2.3 when rolled by this method,
When we measured the amount of iron smear on steel plate S every 4.5,
As shown in the curves A, B, and C in Figure 3 (from the inlet side of I'!li stand 1 to the outlet side of N115 stand 5, the amount of iron smearing has been reduced by almost half compared to the conventional one, Therefore, it was possible to obtain a cold-rolled steel sheet with higher cleanliness than before.

In addition, curve A in FIG. 3 is based on detergent oil, curve B is based on high pressure washing water, and curve C is based on hot water.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the amount of iron smear on the steel plate between each stand in the conventional cold rolling method, Fig. 2 is a schematic diagram showing an example of the method of the present invention, and Fig. 3 is the invention of the present invention. It is a graph showing the amount of iron smear on the steel plate between each stand in the method. Applicant: Kawasaki Steel Corporation

Claims (1)

[Claims] When rolling a steel plate to be rolled by a tandem cold rolling mill row, the iron smudges adhering to the rolled steel plate are removed by detergent oil, hot water, or high-pressure washing water on the entry side of the first stand of the rolling mill row. A cold rolling method for obtaining a high-cleanliness steel plate, which is characterized by removal by injection.