cold forming.ppt

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Introduction Terminology Processes Benefits Coatings and Lubricants Applications Steps to Manufacture Coatings and Lubricants Material Characteristics

Cold Forming TerminologyCold Forming terms:

Cold Heading: cold

forming process in which the force of the punch must exceed the materials elastic limit to cause plastic flow limit = yield strength operation without the heat

elastic

forging

Cold Forming TerminologyCold Forming terms:

Cold Extrusion decreasing reduces

the diameter of the blank by pushing it through a smaller hole size without yield loss

Cold Forming: generic

term describing the combination of cold heading with cold extrusion

Applications:

Cold forming machines - by the number of dies and blows for

example:

1 Die/2 blow

2 Die/3 blow2 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

Benefits of Cold FormingAdvantages 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

Applications for Cold Formed PartsAutomotive 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 PartsConstruction, 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

Process Chain of Cold Forming

Raw Material

Heat Treatment

Surface Treatment

Cold Forming

Formed Part

Metal Removal

Heat Treatment

Metal Removal

Finished part

Coatings and LubricantsCoatings 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 LubricantsLubricants Types soaps calcium stearate sodium stearate

drawing oils Metal-removing coolants oil emulsion synthetics

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.

Coatings and LubricantsProcessHot Rolling Drawing

LubricantWater Pre-coat: phosphate, lime, oxalate Lubricants: Soaps, Oils

Cold Forming Thread rollingCutting/slotting

OilsMetal removal coolant: Emulsion, Solution, Oil Metal removal coolant: Emulsion, Solution