VAL’s billet casting line comprises of state-of-the- art Wag staff Air Slip casting unit with all associated in-line metal treatment facilities consisting of Dual rod grain refiner unit , Degassing unit and Metal filtration unit. Air slip casting technology together with the installed in-line treatment facilities ensures that products cast through the line meet all internal and surface quality requirements . The casting unit is fed by 2 electrically heated tilting type furnaces. Cast billets are homogenized before they are cut to the required lengths and packed at the sawing facility. At every stage of production there is inspection for physical defects and products meeting the customer requirement are handed over to Logistics for on-ward shipment. Apart from the physical inspection ,the chemical composition and internal properties are also checked in our in-house laboratory which is equipped with latest analytical facilities like ARL 4460 – OES make thermo for chemical composition, Automatic Milling machine make Herzog for sample preparation, Metallography Instruments make Buehler for analysis and sample preparation.

VAL’s casting facility is currently equipped to produce 7’’, 8’’ and 9’’ diameter billets in 6xxx1 &1xxx series alloys.

General Information :

Among the salient features in the production of billets, the following could be mentioned:

Online Liquid metal Treatment :

The on-line refining system ,consists of SNIF PI80 degasser followed by 23x23x2inch dual ceramic foam filtration of 40 PPI .The injection of tiny bubbles of inert gas (Nitrogen) in molten metal and subsequent filtration through a ceramic foam filter (CFF) , ensures high degree of efficiency in hydrogen and inclusion removal from molten aluminium .The combination of these two enables the billet produced suitable for all critical applications.

Casting Technology :

Air-slip casting with dual jet cooling technology not only provides extremely smooth surface finish but also ensures high rate of solidification.

Air-Slip technology increases billet quality providing an extremely smooth surface ,minimum shell zone thickness, uniform fine grain structure and minimum dendritic arm spacing.

Homogenization Process :

Homogenization process of the 6000 alloy series is carried out in Batch type Homogenization system consisting of a heating furnace, and cooling chamber having facility of cooling through both Air and water.

The Batch type homogenizing furnace with tight temperature control facilitates homogenization of different alloys and sizes as per the desired requirement .The temperature is controlled through thyristor based control system which works in PID control ensuring very precise control of temperature with a maximum variation of +/- 10 degree C.

As a result of this, our customers can expect superior extrusions every time; higher extrusion speeds, reduced break-out pressure ,longer die life, more consistent as-extruded surfaces ,better consistent anodizing response and improvement in mechanical properties.

Chemical Composition : All values are expressed in %

table

Metallurgical Characteristics Limits :

Variable

Specification

Reverse segregation

Max.600 µm

Shell Zone

≤ 2.0 mm

Grain Size

< 200µm

Hydrogen Content

≤ 0.20 cm³/100 g of AI

Inclusion content

≤0.20 mm²/Kg AI

Alkalis

≤ 0.0015%each

Phase transformation Beta to Alpha (AL-Fe-Si)

≥ 90%

Phase Size (AL-Fe-Si)

NA

Mg2Si (Dimension)

Size : ≤ 2 µm

Mg2Si (Situation)

Precipitate uniformly distributed in the aluminium matrix and

structure as fine as possible , mostly of Mg2 Si as Beta- prime.

Particles ≥ 5 µm

Less than 10 %

Dimension Tolerance :

Diameters:

Diameter 7 in. (178 mm): +/- 1.0 mm
Diameter 8 in. (203 mm): +/- 1.0 mm
Diameter 9 in. (228 mm): +/- 1.0 mm

Length Tolerance :

Length : The tolerance on length must obey +/- 20 mm.

Bow Tolerance :

The billets obey the maximum bending tolerance of 2mm/m at any point and no more than 10 mm in total length. To measure the bending in all its extension, we use a string or nylon .

Cutting Angle :

The angle formed by the cut face of the billet and the axis of the log is 90º±0.5º

Packing :

packing

Billet Length In mm

No. Of Wooden runners

Number of Straps

5800

3

5

Identification :

10 digit batch no. ,Alloy Code & weight are mentioned on the billet. BAR Code is put in 3 places in a bundle.

packing1

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