23-01-2013, 01:19 PM
Indian Ordnance Factories
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INTRODUCTION
The Indian Ordnance Factories organization, a family of 41 Ordnance Factories under the aegis of its corporate headquarters Ordnance Factory Board, Kolkata, possesses the unique distinction of over 200 years experience in defence production. It is engaged in production, testing, logistics, research, development and marketing of a comprehensive product range in the area of land, sea and air systems.
These factories can be considered as the force behind armed forces.
Indian Ordnance Factories is the oldest and largest industrial setup which functions under the Department of Defence Production of the Ministry of Defence. The ordnance factories form an integrated base for indigenous production of defence hardware and equipment, with the primary objective of self reliance in equipping the armed forces with state of the art battlefield equipments.
Mission:
Production of state of the art battle field equipments.
Vision:
To equip our armed forces with modern defence and battle field equipments.
To continuously modernize our production facilities.
To train and motivate personnel.
To equip ourselves with technologies through acquisition, synergy and in-house R&D.
To continuously improve quality.
To improve operational efficiency and communications by extensive use of information technology.
To improve highest level of customer satisfaction.
To increase customer base in Defence, Non-Defence and Export markets and establish Global Presence.
ORDNANCE FACTORY KATNI
Ordnance Factory, Katni is situated in Katni district of Madhya Pradesh, located on Mumbai-Jabalpur-Allahabad section of W.C.Railway. Katni falls on National Highway No.7 and is 91 KM from Jabalpur.
The factory is ISO 9001:2000 certified. The factory is basically manufacturer of “Heavy Cartridge Cases”. The raw materials used in the ordnance factory are of non ferrous type i.e. the non ferrous materials are used to prepare the equipments.
The Asia’s first Extrusion Press was installed by Britishers at Ordnance Factory Katni.
NEW MELTING SHOP (NMS)
The NMS section is the first step of Ordnance Factory Katni. Here raw material and scrap are melted mainly in Continuous Casting Plant (C.C.P.) and moulded in form of coil, ingots and billets.
These finished products are then sent to various other sections for further processing to be made into the final finished product.
The sections to which they are sent are- Rolling section, H.C.C. section Extrusion section, Cupping shop etc.
CONTINUOUS CASTING PLANT:
Melting of raw material and scrap done in C.C.P. passing through its various parts is as follows:
MELTING FURNACE:
This is the first part of C.C.P. raw material in form of Cu and Zn along with scrap in the ratio of 7:3 is melted in this electric melting furnace(Ajax Watt Furnace) maintained at a temperature of 1030 degree Celsius controlled by Pyro temperature controller.
Various steps involved during charge pouring into the furnace are-
1. Scrap and metal is poured into furnace in following order.
1. Light Scrap
2. Copper
3. Heavy Scrap
4. Zinc
2. Scrap is put in 3-4 steps.
3. In each step flux (Common salt + Borax) is poured.
4. Common salt and flux is poured in 4:1 ratio.
5. While melting, melt is covered with charcoal to prevent oxidation.
6. Slag is removed immediately after melting.
7. Before half an hour of melting, Zinc should be poured and mixed properly.
ROLLING PROCESS:
When a piece of metal is rolled in between two rolls, the thickness is reduced as a result of the compressive stresses exerted by the rolls and it can be treated as a two-dimensional deformation in the thickness and length directions neglecting the width direction. This is due to the fact that the length of contact between the rolls and workpiece is generally much smaller than the width of the sheet passing through and the undeformed material on both sides of the roll gap is restraining the lateral expansion along the width direction.
PICKLING PROCESS:
The blanks which are formed do not have the required colour and surface finish. To get the required properties we go for pickling process in which the blanks are first dipped in the acid where all the impurities and dust is removed. Then they are washed in cold and hot water. After that they are dipped in corrosion resistant chemical.
COLD ROLLING MILL SECTION:
Cold rolled steel strip is characterized by a cross-sectional reduction of at least 25%. In cold rolling, the deformation takes place through force of the rolls supported by adjustable strip. These support the cold rolling process so that the setting force of the rolls can be reduced.
Depending on the intended use, the strip has to be annealed after cold rolling. This step is done in the above mentioned batch annealing. After the annealing process, the material is rerolled. In this process, the material is deformed with little rolling force and little reduction. Through this, the material obtains a smooth, clean surface with a low surface hardening.
In this section 4 passes of 15mm each are done to obtain final thickness of 6.80mm from 15mm.
HOT ROLLING MILL SECTION:
Processes divide into the following:-
Primary processes reduce a cast material into intermediate shapes, such as slabs, plates, or billets.
Secondary processes further convert these shapes into finished or semi-finished products.
The primary function of the Hot Strip Mill is to reheat semi-finished steel slabs of steel nearly to their melting point, then roll them thinner and longer through 12 successive rolling mill stands driven by motors totaling 77,000 hp, and finally coiling up the lengthened steel sheet for transport to the next process.
The Hot Mill rolls slabs weighing up to 30 tons between 30” and 74”. Steel slab 8 to 9 inches thick and up to 36 feet long is rolled into strip as thin as 1/16 inches and up to a half-mile in length.
Because they are rolled and finished above recrystallization temperature, hot-rolled products have little directionality in their properties and are relatively free of deformation - induced residual stresses.
1. Clamping
The first step is the preparation and clamping of the two halves of the die. Each die half is first cleaned from the previous injection and then lubricated to facilitate the ejection of the next part. Sufficient force must be applied to the die to keep it securely closed while the metal is injected.
2. Injection
The molten metal, which is maintained at a set temperature in the furnace, is next transferred into a chamber where it can be injected into the die. Typical injection pressure ranges from 1,000 to 20,000 psi. This pressure holds the molten metal in the dies during solidification. The injection time is very small in order to prevent early solidification of any one part of the metal.
3. Cooling
The molten metal that is injected into the die will begin to cool and solidify once it enters the die cavity. When the entire cavity is filled and the molten metal solidifies, the final shape of the casting is formed. The die cannot be opened until the cooling time has elapsed and the casting is solidified.
4. Ejection
After the predetermined cooling time has passed, the die halves can be opened and an ejection mechanism can push the casting out of the die cavity. The ejection mechanism must apply some force to eject the part because during cooling the part shrinks and adheres to the die
5. Trimming
During cooling, the material in the channels of the die will solidify attached to the casting. This excess material, along with any flash that has occurred, must be trimmed from the casting either manually via cutting or sawing, or using a trimming press.