cold forming.ppt

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