coil and cut sheet handling and protection -paresh shah, jsw

7/27/2019 Coil and Cut Sheet Handling and Protection -Paresh Shah, JSW

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Coil & Cut Sheet Handling

and ProtectionMr Paresh Shah, DGM, JSW Steel



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(Layer 1) – Top coat in various colours

(Layer 2) – Suitable Primer

(Layer 3) - Pretreatments.

(Layer 4) – Zinc or Al-Zn coating

(Layer 5) - steel sheet

(Layer 6) Back coat

Introduction

Configuration of Prepainted material



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Topics covered

Handling of Material – In Plant

Transportation

Handling and Preservation at Warehouse

Handling and Preservation at Job site

Care to be taken during Forming and installation

–

Dos and Don'ts



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Handling of Material at Plant



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Handling of Material

Care taken at plants:

Packet lifted with Woolen felt only

to avoid damage to edges.



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Coil handled with C-Hook

padded with Woolen felt.

The floor should be flat &

clean.




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In the plant, Padding on

hooks and other handling

devices helps to avoid damage

on edges.

Cushioning materials like

feltboard and polyurethane

protect coils while they are

moved, placed in inventory or

shipped.




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Material stored in dry and good ventilated shed




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Coil kept on Rubber pads to avoid dent on outer wraps




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Always keep the material in a dry, shaded and good ventilated area.

Do not keep the material under direct sunlight and open area.

Do not keep the material on wet floor (water, rain, etc.).

If not required for immediate use, provide cover to protect the material

If Sheets become wet during storage, it should be separated without

delay & surface moisture removed with clean cloth. The steel sheets

then be stacked so that air circulation completes the drying process.




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Good Storage conditions can eliminate the followings:

Moisture penetrating between the Sheets.

Moisture or water penetrates between the Sheets through the wooden

pallets.

Wet storage staining.

White rust.

Paint peel off.




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What is White rust & How it is caused?

White rust is a complex, hydrated zinc carbonate/zinc hydroxide. It is a corrosion

product of zinc which is formed under specific conditions of exposer.

The most common causes of white rust are :

Ingress of water, due to rain water between the adjacent surfaces in a stack of

galvanized or pre painted steel or sheets or within windings in a coil during either

transportation or storage.

Condensation within a coil or sheets due to rapid changes in temperature,

Condensation from the drying out of new buildings or laying & drying out of wet

concrete.

Prolonged , adverse storage or inadequate protection during transportation allowing

considerable water ingress between stacked coils or sheets results into some time

red rust also .



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Transportation



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Transportation

Transport driver should check material must be covered with

double tarpaulin.

Other goods should not be transported with pre painted material.

Ensure no water seepage during transportation.

Ensure there should be no hole on the floor of truck to avoid water

seepage.

Truck platform should be flat



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GI coils and Packets:

Coils and packet have to be kept on the wooden Block on Floor

Proper Lashing to be done

Never allow a coil to contact the floor directly.

Transportation



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BGL, PPGI and PPGL Coils :

These products have to be Kept on the truck with vertical packing (Eye to

sky) to avoid transit rubbing marks on the surface.

Truck needs to be covered with tarpaulin to avoid any water seepage during

transportation.

Transportation



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Warehouse



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Storage of coated steel product at Warehouse

Following care needs to be taken for the coated steel product to

avoid any damage to the coating

Avoid the water seepage inside the packed coils and packets.

Material is to be kept on the Dry surface to avoid moisture contact.

Packed coil and packets are to be store and stacked properly in a closed

shade to protect the material from the rain water.



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Stacking of material

Coils should remain packaged to prevent rust till further processing

Partially processed coils should be repacked for future use

Coils should not be allowed to butt-up against safety rails or walls

or floor plates

Metal-on-metal contact should be avoided whenever possible.

Coil/sheet stock should be stored in dry conditions.

The floor should be free of debris.

Minimize coil stacking, but when required

Band clips should not reside between touching coils

Felt strip padding should be placed between coils

Narrower coils should be stacked on wider coils

Highter weight coils should be stack on heavier coils



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Coils should be stacked with sufficient

distance in between for SAFE material handling

Coils should not be stored in open yard

Stacking of material



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Recommendations :

Ensure the material condition is OK during unloading of the material.

If any deviation is observed, same should be recorded in L.R. copy.

Ensure there should be no damage to the goods during unloading

(woollen felt, Rubber coated C-Hook etc. can be used)

Do not slide sheet on rough surface or over each other.

For personal safety and to protect the surface finish, wear Clean, Dry

Hand Gloves.

Rotated on a first-in/first-out basis

Organized to minimize unnecessary coil/sheet movement

Arranged so coils can be easily reached in the order you plan to use

them



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Stack Corrosion

Water is a necessary perquisite for corrosion of stored pre painted panels

Water or water vapor may penetrate between panels or coil wraps due to

capillary action

Ambient humidity and temperature cycles will also promote water intrusion into

stored panel bundles through condensation.

Besides water, two other important factors that contribute to the corrosion of

stored pre painted panels are temperature and exposure time. Corrosion willaccelerate with increased temperature. Given enough time, panel bundles

will eventually become wet and storage corrosion may occur under

most job site panels.

Storage/ stack corrosion can be prevented by:

Reducing site storage time.

Decreasing water contact.

Moderating temperature extremes



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Material Kept on soil - no flooring

To be avoided



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To be avoided

Material Kept in open condition



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To be avoided

Improper Material handling causes fold mark / scratches on the sheets



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To be avoided

Inadequate warehouse building



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Handling of Material at Job Site

H dli f t i l t J b Sit



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Handling of material at Job Site

Material should be stored in covered condition

Material to be kept slightly above the ground by using wooden

rubber plank.

Do not slide sheet on rough surface or over each other.

Contact with water / mud should be strictly avoided

For personal safety and to protect the surface finish, wear Clean,

Dry Hand Gloves.

After Erection / Assembling, Guard film should be removed

immediately.




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When lifting bundles with a forklift,

forks must be a sufficiently apart to

avoid buckling of the sheets.

Do not transport open bundles.

Forklift arms should be padded

If Coil is handled with Hydra, nylon

slings should be used with sufficient

padding on the edges.





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Panels in bundles should be lifted at their center of gravity.

When lifting bundles with a crane, a spreader bar and nylon

straps should be used. Never use wire rope slings.

Individual panels should be lifted vertically by the seam.

If the panel is over 10 feet long, lift it with two or more peopleon one side to prevent buckling

Do not pick up the Panel by the ends.




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Actual on-site photos



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Material should not be stored in open and wet condition

AVOID – Storage of material in mud water



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Material should be protected from water – During storage as well

as during forming at site

AVOID - Stacking of material in mud



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AVOID – Dirt accumulation on the sheets

Material should be stored in covered and dry condition



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AVOID – water entrapment in the packet

Water entered in

the packet



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Iron fines from drilling, saw cut chips & fasteners lying

can cause rust stains.

Leaving debris on the sheets may lead to such type defects. Sweep

swarf from roof after finishing installation

AVOID – leaving Debris on the sheet



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Proper Fastener Installation procedures to be followed



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For Bare and Prepainted Galvalume products, direct contact with

cement foundations is not recommended.

Accelerated corrosion can occur due to the lime contained in the

cement.

AVOID - Contact with Cement



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Metal debris from sawing, drilling and other construction processes should

be removed during installation. Otherwise, the metal filings will red rust on

the surfaces where they were deposited. Red rust of the metal filings may

cause stain or discoloration on the surface of the panel whether it is bare or

painted and cause appearance issues.

AVOID – Metal Filings



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AVOID – Dirt Accumulation on the sheet

Two types of dirt accumulate on buildings: dry soil and greasy or organic

residues.

The dry dirt, by itself, washes off with rain or high-pressure water spray.

Greasy residues do not wash off in rain and hold dry soil and chalk tightly to

the surface.

Guard Film / Lamination



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This water entrapment is because of the capillary actions of the Gap Between

sheets which get entrapped in the packet while stacking / storage.

As the permeability of paint coating increases in intact conditions, this failure /

phenomenon will result.

This is highly restricted for the pre painted products hence not a process

defect. Guard film should be removed immediately after installation

Water can enter through Guard film, which may lead to paint peel

off as shown above.

Guard Films are provided

only for forming

operations and to avoid

handling scratches

Guard Film / Lamination



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Forming Operation

Roll Forming Operations



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For Roll Forming of pre painted material, Rolls should be properly

polished. There should not be any damage on the rolls.

Maintain the roll forming equipment to achieve proper vertical and

horizontal tooling alignment, as well as adequate clearance between the

mating top and bottom spindle rolls to avoid abrading the coating.

Clean the rolls to avoid damage to the paint finish.

Incorporate the appropriate number of roll forming stages to ensure

smooth transitioning of bends.





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Use suitable paint system to maximize performance at bends.

Design the roll former to accommodate the strength of the steel grade.

For example, a higher strength steel may require more roll former stands to

successfully produce a given profile.

Use lower strength steels to allow greater design latitude when making

more complex profiles. eg. - Tile Profile





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Roll damage may lead

to paint peel off during

roll forming

Rolls should be

properly polished to

avoid damage to paint


Roll Damage

Paint peel off

Summary



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Pre painted material consists of various layers of paint system.

This paint system, if used properly can give maximum life span and

best appearance possible.

This is not a metal bonding and susceptible to physical damage if not

handled properly at various stages of operation.

Before installation – store in dry

keep covered

ship in covered condition

handle as per the guide line

onsite protection

Summary

Colour Coating Line Product Range



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Strip thickness : 0.20 - 1.50 mm

Substrate : Galvanized & Galvalume Steel

Strip width : 600 - 1250 mm

Coil ID : 610/508 mm

Coil OD : 1500 mm max.

Weight : 3 - 10 T

Coating material : Polyester, Si-Polyester, Polyurethane,

PVDF, Epoxy

Primer Coating Thickness : Top = 5 μ max

: Bottom = 5 μ max

Top & Back Coat thickness: Top = 25 μ max

: Bottom = 5 μ max

Guard Film : Optional

Colour Coating Line Product Range



THANK YOU

coil and cut sheet handling and protection -paresh shah, jsw

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