The present invention relates to novel method of creating differential roll roughness on work roll surfaces and the work rolls thus produced. The invention particularly relates to a method of creating desired size and shape of lettering_ or logo marking for imparting onto the surface of cold rolled skin passed product.
In the cold rolling mill (CRM) of steel industry, skin passed

rolling process succeeds cold rolling and annealing processes. One of the main purposes of skin pass rolling is to impart the desired surface roughness on the sheet which is termed as "surface texture". Other purposes of skin pass rolling includes elimination of metallurgical defects called "stretcher strains" and minor shape correction of ,the product rolled. Typically, skin pass mill is the last processing unit for the manufacture of "cold rolled close annealed" (CRCA) products in coil form. It has been felt necessary to brand selected CRCA products before they are finally distributed to the market. This branding involves marking the surface of CRCA products by specially designed lettering or logo.
There are conventional methods of marking or branding of a rolled product such as ink jet marking or ink stamping. But these methods of branding the products do not work in the particular situation at the applicant's CRM for more than one reason. It has. therefore been the endeavour of the applciant to invent a methodology by which a permanent impression can be created on the surface of the cold roll sheets.
It is an object of the present invention to provide a new method
of creating a differential roll roughness on work roll surfaces
within in/specific shape and sizes.
Another object of the present invention is to create any size or shape of lettering or logo subject to certain maximum dimensions allowed by the hardware of the texturising machine, whcih can then be imparted to the surface of cold rolled skin passed CRCA coilsduring rolling.
A further object of this invention is to create a permanent
impression on the surface of the cold roll sheets in such a
manner that only the surface roughness is different inside and outside the 1ettering/logo.to enable appearance.
A still further object of the present invention is to produce branded CRCA products from the applicant's cold rolling mill (CRM) for the first time by creating differential roughness roll surface on the work rolls of skin pass mill.
A still another object of the invention is to provide a novel method of writing letters/brand/logo on the surface on the sheets at skin passed mill that does not get earsed due to oiling rubbing and/or smudging.
According to the present invention there is provided a method of creating effective branding or marking of coil surface of cold rolled close annealed (CRCA) products in coil form, which method comprises the following steps -
i) grinding the roll surface,
ii) texturing the roll at logo/lettering portion to
provide on the inside of logo/lettering the required roughness with
the help of electro discharge texturing machine and dielectric as
herein defined,
iii) cleaning the entire roll above the textured portion, iv) marking the logo/lettering on the initial textured portion of the roll, v) texturing the entire roll to provide required roughness unloading
and wrapping the roll,
vi) cleaning unloading and wrapping the roll, vii) sending the ready roll to skin pass mill for logo/lettering marking on
CRCA product.
In the above method, if the logo is found to have been not marked as desired, said roll is returned after cleaning for marking again.
After texturing with normal sequence of operation in the above method of creating effective branding, if the roll is found not desirable after inspection, is returned to step of grinding.
In the above said method, differential roll roughness is created on work roll surfaces in specific shape and sizes.
The lettering and logo size on the roll of predetermined size is imparted onto the surface of cold rolled skin passed CRCA coils.
The new method developed by the inventors is applicable for specially prepared work rolls. When these specially prepared work rolls are used at skin pass mill to roll coils to be branded, the marks on the rolls get transferred onto the surface of the coil creating perfect impression of the lettering or logo due to difference of the roughness between the outside and inside of the lettering or logo which enable the appearance.
Advantage of the present invention over the prior art
a the novel method of the present invention allows effective branding or marking of coils surface of CRCA in coil form directly skinpass mills. This method is especially designed to work effectively under unfavourable harsh conditions of high speeds, oiling and lack of available space which render the conventional methods ineffective.
b. there will be no need to subject the coils to go through additional recoiling processes just to allow marking of the surface by alternative conventional methods,
c. additional capacity of recoiling is not available at CRM to cany out marking of coil surface, particularly belonging to trade and distribution sectors,
d the cost of such additional processing would negate any advantage derived by branding. As per the novel method of the present invention, there will be no additions to the existing cost of manufacturing.
e. the product produced by the novel method of the present invention is not amenable to be copied illegally and/or tampered with.
The present invention and the various steps thereof are illustrated in the flow diagram as shown in the accompanying drawing.
The skin pass mill work roll on which logo marking is required is firstly grinded. After grinding (1) the roll is textured on the portion of roll where the logo/lettering is
required to provide the necessary initial roughness inside the logo lettering by an Electro Discharge Texturing Machine (EDT). On completion of texturing_operation (2) the excess dielectric is wiped out from the roll surface by a wiper. Logo marking/lettering marking on the rolls is carried out by fixturing on the roll barrel by wrapping the roll with a logo protective marking paper on the center of roll barrel with openings to the roll circumference where logo/lettering is required, cleaning the said opening surface area of the roll on providing logo template/stencil under the opening area and spraying an aerosol provided for logo/lettering marking on the template, the chemical of the said aerosol entering into the cut out of stencil to create the exact shape of logo after drying. If the inspection of stepNo.5 is not ok the logo/lettering is removed and cleaned with a special cleaner and step No.4 is followed to remake the logo/lettering. Thereafter the entire roll is textured to provide required roughness outside the logo/lettering. The roll surface is followed by further inspection of roll surface, followed by cleaning, unloading and wrapping and the roll becomes ready for logo/lettering marking on CRCA sheet
The invention described hereinabove is in relation to non limiting embodiments within the scope of the invention as defined by accompanying claims.
WE CLAIM
1. A method of creating effective branding or marking of coil surface of cold rolled close annealed (CRCA) products in coil form, which method comprises the following steps -
i) grinding the roll surface,
ii) texturing the roll at logo/lettering portion to
provide on the inside of logo/lettering the required roughness with the help of electro discharge texturing machine and dielectric as herein defined,
iii) cleaning the entire roll above the textured portion,
iiv) marking the logo/lettering on the initial textured portion of the roll, v) texturing the entire roll to provide required roughness unloading
and wrapping the roll,
vi) cleaning unloading and wrapping the roll, vii) sending the ready roll to skin pass mill for logo/lettering marking on
CRCA product.
2. A method of creating effective branding or marking of coil surface of cold rolled close annealed (CRCA) products in coil form as claimed in Claim 1 wherein after marking the coil with logo if found not ok said roll is returned after cleaning for marking again.
3. A method of creating effecting branding or marking of coil surface of cold rolled close annealed (CRCA) products in coil form as claimed in claim 1 if found
not ok is returned to step of grinding.
.
4. A method creating effective branding or marking of coil surface of cold rolled close annealed (CRCA) products in coil form as claimed in any of the preceding claims wherein differential roll roughness is created as herein defined on work roll surfaces in/within specific shape and sizes.
5. A method of creating effective branding or marking of coil surface of cold rolled close annealed (CRCA) products in coil form as claimed in any of the preceding claims wherein lettering or logo size of predetermined size is imparted onto the surface of cold rolled skin passed CRCA coils, which is visible due to effect of differential roughness between outside and inside of the logo.

6. A method of creating effective branding or marking of coils surface of cold rolled close annealed (CRCA) products in coil form substantially as herein described and as illustrated in the accompanying drawing of complete
specification.
This invention relates to a method of creating effective branding or marking of
coil surface of cold rolled close annealed (CRCA) products in coil form, which
method comprises the following steps -
viii)grinding the roll surface,
ix) texturing the roll at logo/lettering portion to
provide on the inside of logo/lettering the required roughness with
the help of electro discharge texturing machine and dielectric as
herein defined,
x) cleaning the entire roll above the textured portion,
xi) marking the logo/lettering on the initial textured portion of the roll,
xii) texturing the entire roll to provide required roughness unloading
and wrapping the roll,
xiii) cleaning unloading and wrapping the roll,
xiv) sending the ready roll to skin pass mill for logo/lettering marking on
CRCA product.