Stock material
The material out of which stampings are made is known as stock materials stampings can be made from metallic or non metalic materials.Metalic materials include ferrous and non ferrous metals.
Ferrous metals
- hot rolled steels
- cold rolled steels
- stainless steels
- spring steels
Non ferrous metal
- copper
- Brass
- bronze
- aluminium
- tin
- zinc etc.
Non metallic materials
- plastic
- rubber
- wood
- cloth
- paper etc.
Stock strip
Stock strips are fed into the tool.They are advanced through the required advance distance at each press stroke for a series of repetitive operations.
Unit stock
Stock materials which are fed individually into the tool for processing are called unit stock.
Piece part
A piece part is a product of a tool.It may be
- a complete product in itself.
- one component of a product.
Ferrous metals
Hot rolled steel sheets
They are used for manufacturing where scaling and discolouration are not objectionable.The surfaces are painted after operation(if required).
Pickled and oiled sheets
Immersing hot rolled in acid solutions results in smooth clean scale free surface.oiling protects the surface against rusting.Pickled and oiled sheets are used in the manufacture of parts for household appliances,automobile parts,toys etc.The sheets can take long lasting painting due to the absence of scales.
medium carbon steels
These are hot rolled steels having 0.4% to 0.5 % carbon.They are hard,tough and resistant to abrasion.
Cold rolled sheets
They have a smooth deoxidised finish.This provides excellent base for paint lacqur or enamel coating.The thickness of the sheet is uniform.They are available in six gades of hardness.
Hard
Hard sheets and strips cannot bend in either direction of the grain without cracks or fracture.Such sheets are used for pproducing flat blanks that require resistance to bending and wear.
Three quarter hard
Three quarter hard strips can be bend to an angle 60 degree from flat only across the grain.
Half hard
Half hard steel strips can be bent to 90degree across the grain.
Quarter hard
This can be bent over flat (180) across right angle along the grain.
Soft
Soft grades of steel can be bent over flat(180 degree) both across and along the grain direction.
Dead soft
This grade of steel is used for severe forming and drawing operations.
Deep drawing steel sheets
They are cold rolled low carbon steels.They are throughly annealed,deoxidised and oiled.Deep drawing sheets are used for difficult drawing,spinning and forming operations.
Silicon steel
Silicon steel is used for electrical laminations.
Stainless steel
They are used where corrosion resistance is a requirement.
Non ferrous metals
Copper and its alloys are widely used as a stock material.They are good conductors of heat electicity and also are highly non-corrosive.
Copper alloys include
Beryllium copper
Red brass
Low brass
Cartridge brass
Yellow brass
Muntz metal
Phospher bronze
Other non ferrous metals used are
- aluminium and aluminium alloys.
- magnesium and magnesium alloys.
Rare metals
Rare metals like zirconium,tantalum,vanadium,tungstun and molybdenum and their alloys are used press working.
Precious metals
Precious alloys like that gold silver,platinum etc are used for manufacturing laboratory equipment and electrical industry.
Clad metals
It consists of a core of one metal and a covering layer of dissimilar metal.
Preparation of stock
In steel mills the metal is formed into large sheets by rolling.The sheets are cut into strips in a sheraing machine.Slitting machines are also used to cut the sheets.