Coil Coating Line (CCL)
( Continuous Coating Line)

This is facilities manufacturing cold-rolled products of highest value added, such as color steel sheets which are produced by coating galvanized iron (GI) , electronic galvanized iron (EGI) , cold rolled iron (CR) , aluminum (AL) and stainless (SUS) with coating materials of various color, and then, hardening in oven, and lamination steel sheet which are made by attaching various lamination films.
1. Degreasing and chromate-treating GI EGI CR AL
2. Primer coating, Dry in oven, Cooling
3. Top coating, Dry in oven, Cooling
4. Leveling, Attaching protective films
General Description
1. Entry Section
No. 1 and No. 2 Coil Skid & Coil Car
No. 1 and No. 2 Payoff Reel
No. 1 and No. 2 Pinch Roll with Coil Opener
Threading Conveyor
Entry Shear
Deflector Roll
Stitchener
No. 3 Pinch Roll
No. 1 Steering Roll
Entry Hydraulic Unit
2. Accumulator
Entry Accumulator
Exit Accumulator
3. Steering Unit
No. 2 Steering Roll & CPC
No. 3 Steering Roll & CPC
4. Cleaning Section
Entry Roll
Degreaser & Squeeze Roll
Brush Scrubber & Squeeze Roll
No. 1, No. 2 Hot Water Rinse & Squeeze Roll
Chemical Tank & Squeeze Roll
Dryer
5. Coating Section
Coater
6. Oven
Oven
Cooler
Cooling Roll
7. Tension Bridle Roll
Tension Bridle Roll
8. Exit Section
No. 4 Steering Roll
Exit Shear
EPC Unit & Deflector Roll
Tension Reel
Belt Wrapper
Exit Coil Car
Exit Coil Skid
Exit Hydraulic Power Unit
9. Electrical Equipment
Electrical control panels
Operators panels
Control and automation of the line
PLC control

Coil Coating Line (CCL)
( Continuous Coating Line)
This is facilities manufacturing cold-rolled products of highest value added, such as color steel sheets which are produced by coating galvanized iron (GI) , electronic galvanized iron (EGI) , cold rolled iron (CR) , aluminum (AL) and stainless (SUS) with coating materials of various color, and then, hardening in oven, and lamination steel sheet which are made by attaching various lamination films.
1. Degreasing and chromate-treating GI EGI CR AL
2. Primer coating, Dry in oven, Cooling
3. Top coating, Dry in oven, Cooling
4. Leveling, Attaching protective films
General Description
1. Entry Section
No. 1 and No. 2 Coil Skid & Coil Car
No. 1 and No. 2 Payoff Reel
No. 1 and No. 2 Pinch Roll with Coil Opener
Threading Conveyor
Entry Shear
Deflector Roll
Stitchener
No. 3 Pinch Roll
No. 1 Steering Roll
Entry Hydraulic Unit
2. Accumulator
Entry Accumulator
Exit Accumulator
3. Steering Unit
No. 2 Steering Roll & CPC
No. 3 Steering Roll & CPC
4. Cleaning Section
Entry Roll
Degreaser & Squeeze Roll
Brush Scrubber & Squeeze Roll
No. 1, No. 2 Hot Water Rinse & Squeeze Roll
Chemical Tank & Squeeze Roll
Dryer
5. Coating Section
Coater
6. Oven
Oven
Cooler
Cooling Roll
7. Tension Bridle Roll
Tension Bridle Roll
8. Exit Section
No. 4 Steering Roll
Exit Shear
EPC Unit & Deflector Roll
Tension Reel
Belt Wrapper
Exit Coil Car
Exit Coil Skid
Exit Hydraulic Power Unit
9. Electrical Equipment
Electrical control panels
Operators panels
Control and automation of the line
PLC control Read More..

Paints & Lacquers

The choice of a paint system depends on a number of key factors including aesthetic appearance (shade, gloss, roughness), mechanical properties (abrasion resistance, scratch resistance, impact resistance, formability), durability (color and gloss retention, weathering resistance, corrosion resistance), environmental impact and

cost.

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Inspection & Tests in Colour coating Line

Inspection & Tests methods in Colour Coating

On line:

Liquid paint in the troughs

Appearance of the wet film

Appearance of the dry film

Thickness

Laboratory tests:

Adherence

Crack resistance

Hardness

Abrasion resistance

Bending

Deep-drawing

Dry film thickness

Gloss

Conformity of colour

All controls are followed up statistically

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Colour Coating Line

Definition

Coil coating is a high performance technique of continuous application of an organic coating (paint or film) on metal strip (aluminium or steel) on a coil coating line, before the material gets its final shape.

Coil Coating Process

The metal substrate steel is delivered in coil form from the rolling mills i.e .Cold Rolled steel. The coil can be galvanized in galvanizing line. Coils weight varies from 5-6 tonnes for Aluminium and up to 20 tonnes for steel.

The coil is positioned at the beginning of the line, and then unwound at a constant speed, passing through the various pre-treatment and coating processes before being recoiled.

Two strip accumulators found at the beginning and the end of the line enable the work to be continuous, allowing new coils to be added (and finished coils removed) by a metal stitching process without having to slow down or stop the line.

The following steps take place on a modern coating line:

(1)Mechanical stitching of the strip to its predecessor
(2)Cleaning the strip
(3)Power brushing
(4)Surface treatment by chemical conversion
(5)Drying the strip
(6)Application of primer on one or both sides
(7)Passage through the first curing oven (between 15 to 60 seconds)
(8)Cooling down the strip
(9)Coating the finish on one or both sides
(10)Passage through the second curing oven (between 15 to 60 seconds)
(11)Cooling down to room temperature
(12)Rewinding of the coated coil.

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Why use duplex stainless steel?

By Carl Smith, Contributing Writer
February 13, 2007

Duplex stainless steel is among various metals used in corrosion-resistant applications. This article presents an overview of the material's properties, advantages, and disadvantages and compares it to other materials suitable for corrosion-prone environments. It also discusses welding and forming duplex.

Duplex stainless steel was introduced to the U.S. welding industry in the early '90s when metallurgists, some of the most knowledgeable people in the worldwide welding industry, presented the concept to the electric power industry in Columbus, Ohio, near the American Electric Power headquarters. A consortium comprising several companies collected the information for the presentation. L. Van Nassau, H. Meelker, and J. Hilkes from Norweld of the Netherlands performed extensive research relating to welding duplex materials. Dr. Damian Kotecki from Lincoln Electric and Dr. Trevor Gooch (now deceased), a private consultant from the United Kingdom, were the keynote speakers at the initial seminar. The primary focus was on welding the duplex material, but the development of usage areas for the material was equally well-depicted.

The information was so well-presented to the fabricators, engineering firms, and individual consultants in attendance that it created an immediate response for usage in many industrial areas. Industries represented at the seminar included electric power companies, chemical producers, petroleum processors, welding engineers, transportation equipment manufacturers, and welding supply organizations.

What Is Duplex Stainless?

The word duplex is based on the concept of austenite and ferrite formulated in the same material. The user may require a briefing about the material's composition, but in general, the most important aspect is what it will do in use. Fabricators really are not interested in chemical composition or phase diagrams. They want to know a material's advantages and disadvantages and how difficult or easy it is to fabricate. Metallurgists are interested in the material's composition and the end usage. They may be able to investigate the mechanical, physical, and chemical properties and discover advantages or disadvantages for a particular application.

The following information is intended to provide a useful, but not highly technical, characterization of duplex and superduplex stainless steels' usefulness, advantages, disadvantages, and fabrication ease.

Relative Cost Factors

A possible cost reduction almost always spikes interest in any material. If it is possible to retain quality and reduce material cost, even more interest is spiked. Duplex is cost-effective in more than one way. The material costs less than many other materials used in a corrosive atmosphere. When compared to 300 series stainless steel, the cost reduction is realized in a different manner. Duplex's yield strength is double that of the 300 series stainless steel. This factor allows the use of a thinner material to support a like load.

The cost of fabricating duplex usually is lower than for other materials because of its comparative ease of machining and welding. When high-nickel alloys are welded, small stringer beads and low heat input are recommended. This is not the case with duplex. Higher heat input and a slight weave bead are recommended for this material. The ferrite content causes the welding to be less intimidating than when welding hig- nickel alloys. This factor alone saves significant weld time.

Duplex's machining rate of travel is similar to that of 316 stainless steel with high-speed steel tooling, and duplex requires fewer machining labor hours than high-nickel alloys. Welding wire and gas costs are less with duplex, except when the corrosive atmosphere is extreme. In the case of severe corrosion and the possibility of stress corrosion cracking, it is necessary to use ERNiCrMo-3 wire, which is much more expensive (around $30 per pound) than ER2209 (around $11 per pound), which is the matching filler wire.

Forming duplex is not complicated. The material can be bent and rolled by almost the same methods as 50,000-PSI-yield- strength material. Conventional rolls and dies are sufficient for forming most shapes, which eliminates the added cost of purchasing special rolls and dies. The only significant requirement is that the dies and rolls must have a hardness of at least 34 Rockwell C to prevent carbon impregnation.

Advantages in Performance

There is no such thing as an all-purpose material for corrosion resistance, just as there is not just one corrosion type. Duplex alloys are in a class with several other materials for various types of corrosion resistance. Some of the corrosive environments listed below depict these differences. There are many more types of corrosive conditions but these are some for which stainless and nickel alloys are suitable.

Environment	Problem	Poor	Good	Best
Chlorides	Pitting, crevice corrosion	300 Series SS	Duplex alloys 317LXN®	Alloy 276 AL6XN®
Chlorides/Halides	Stress corrosion cracking	300 Series SS	Duplex alloys	Alloy 600/625 AL6XN®
Hydrochloric Acid	Pitting, crevice corrosion	Titanium, Duplex, 20 Cb-3	Alloy 22, 276	Zirconium, Tantalum
Hydrofluoric Acid	Pitting, crevice corrosion	Duplex Alloys	Silver, Gold	Copper, Alloy 400
Sulfuric Acid	Pitting, crevice corrosion	Copper-Nickel (MONEL®) Alloy 601	20 Cb-3	Alloy 622 HASTELLOY® C-22
General Acidic Attack	Critical Pitting	300 Series SS	317LNMo Duplex Alloys	Alloy 25-6 Mo Alloy 625

® AL6XN and 317LXN are Trademarks of Allegheny Ludlum Steel. ® MONEL and HASTELLOY are trademarks of Allegheny Ludlum Steel. ® Nitronic is a trademark of U.S. Steel.

As the table shows, some alloys outperform duplex alloys in many environments. Duplex is better than the 300 series in nearly every category. The consideration in the case of chlorides and halides must include costs.

Duplex alloys are nearly equal in strength to the C276 and AL6XN alloys. The pitting and crevice corrosion resistance of C276 and AL6XN are only slightly superior to the duplex alloys'. The corrosion rate for duplex is 23 mil/year; AL6XN is 17 mil/year. (Boiling NaOH, 290 degrees F for 48 hours.) Duplex alloys are much more readily available than higher-nickel alloys.

The elements that provide the strength and corrosion resistance in duplex are much more common than those found in some high-nickel alloys. For instance C276 contains tungsten. Carpenter 20Cb contains columbium and tantalum. The 625 alloy contains columbium, tantalum, cobalt, and titanium. Chromium, nickel, molybdenum, and nitrogen are common elements that provide the strength and corrosion resistance in the duplex alloys. The nitrogen is used in much the same way as it is used to protect the surface of Nitronic® 30.

Disadvantages

Welding duplex alloys is not particularly difficult, but the heat input and interpass temperature must be controlled to maintain the ferrite-austenite balance. Otherwise, the advantages of using the duplex material will be sacrificed. The time spent at 1,300 degrees F to 1,800 degrees F must be controlled. The heat-affected zone (HAZ) time-at-temperature is critical in controlling the intermetallic phases.

If the matching filler wires or electrodes (ER2209 or E2209) are used to join the material, there is a slight disadvantage versus using the more expensive ERNiCrMo-3 or ENiCrMo-3 welding materials in the area of crevice corrosion. The nickel content of E2209 and ER2209 is in the range of only 7 percent to 9 percent, while the nickel content of ERNiCrMo-3 and ENiCrMo-3 is 56 percent to 58 percent. The addition of columbium and niobium limits the carbide precipitation in the HAZ. This cost is worthwhile, but it slightly diminishes the duplex's cost advantage.

Another disadvantage is in the rolling and bending process. Duplex's tensile and yield strength and the work-hardening tendency cause springback and sometimes re-forming. This is not always the case, but is common in materials thicker than 3/4 in.

There are advantages and disadvantages with all materials, as well as specific methods to overcome the disadvantages. Overall, the advantages of duplex materials make themna great addition to the ever-growing compilation of materials. Using these alloys in the power generation field has proven to be valuable for the scrubber fabrication.

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Waste gas incinerator
Drying chamber of colour coated sheets

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Colour coating line

Inside the Colour Coating line

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Here one can write any information regarding Colour Coting Line...its very interesting and useful as its all about sharing your knowledge..so please try it Read More..