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Introduction Terminology Processes Benefits Coatings and Lubricants Applications Steps to Manufacture Coatings and Lubricants Material Characteristics
Cold Forming terms: Cold Heading:
cold forming process in which the force of the punch must exceed the material’s elastic limit to cause plastic flow
elastic limit = yield strength
forging operation without the heat
Cold Forming Terminology
Cold Forming terms: Cold Extrusion
decreasing the diameter of the blank by pushing it through a smaller hole
reduces size without yield loss
Cold Forming: generic term describing the combination of
cold heading with cold extrusion
Cold Forming Terminology
Applications: Cold forming machines - by the
number of dies and blows for example:
1 Die/2 blow
2 Die/3 blow
2 Die/4 blow
Open Extrusion Trap Extrusion
30% area reduction 75% area reduction
• Examples using trap extrusion and open extrusion.
7 Station Cold Forming Process
Fig : 1 Cut off to specified length
7 Station Cold Forming Process
Fig 2 : Squring
7 Station Cold Forming Process
Fig 3 : Impact Extruction
7 Station Cold Forming Process
Fig 4 : 2nd Blow Extrusion
7 Station Cold Forming Process
Fig 5 : Backward Extruction
7 Station Cold Forming Process
Fig : 6 Forward Extrusion
7 Station Cold Forming Process
Fig 7 : Finishing Blow
Advantages of Cold Forming Design Versatility
High strength parts from non-heat-treatable alloys
Most cost effective way vs. milling, machining, hobbing and chemical etching
High production rates Metallurgical Effects
Grain flow Improves strength, hardness, toughness &
fatigue resistance Material Savings
Benefits of Cold Forming
Automotive brake parts ball joints & steering parts starter pinions oxygen sensors constant velocity joints manifold bolts engine valves
Appliance Industry gears fasteners for assembly
Applications for Cold Formed Parts
Construction, Off-road equipment bolts, nuts screws – tapping, window,
roofing, deck transmission gears similar parts for automotive
Aerospace rivets, fuselage engine bolts fasteners - landing gear,
interior
Applications for Cold Formed Parts
Raw Material
HeatTreatment
SurfaceTreatment
Cold Forming
FormedPart
Metal Removal
HeatTreatment
Metal Removal
Finishedpart
Process Chain of Cold Forming
Coatings Uses
prevent metal to metal contact with tooling, galling act as a carrier for machine lubricants
Types precoat lime copper plating zinc phosphate molybdenum disulfide oxalate
Coatings and Lubricants
Lubricants Types
soaps calcium stearate sodium stearate
drawing oils Metal-removing coolants
oil emulsion synthetics
Coatings and Lubricants
Since cold working is done at room temperature or low temperature , no oxidation and scaling of the work material occurs
This results in reduced material loss. Thin gauge sheet can be made by cold
working(forming) Since higher force are required, High capacity and
costly machines are needed for cold working. Severe stresses are set up in material during the
cold working.
Process Lubricant
Hot Rolling Water
Drawing
Pre-coat: phosphate, lime, oxalateLubricants:
Soaps, Oils
Cold Forming Oils
Thread rollingMetal removal coolant:Emulsion, Solution, Oil
Cutting/slottingMetal removal coolant:
Emulsion, Solution
Coatings and Lubricants