Andrzej Matuszak

1

Bulk Deformation

Bulk Deformation

Forming

Forming

Część 2

Forging

Forging

Stanisław Erbel, Kazimierz Kuczyński, Zdzisław Marciniak

Obróbka Plastyczna

seria: Techniki Wytwarzania.

PWN Warszawa 1981

Andrzej Matuszak

2

Characteristics of Products Formed

Characteristics of Products Formed

by Forging

by Forging

• Forging

– Produces discrete parts with a variety of

unlimited shapes; Typical properties better
than extrusions;

– Surface finish fair to good; High die and

equipment costs; Moderate to high labor
costs; Moderate to high operator skill

Andrzej Matuszak

3

Open Die Forging and Cogging

Open Die Forging and Cogging

(kucie swobodne, spęczanie wstępne)

(kucie swobodne, spęczanie wstępne)

• Simplest and cheapest
• Also called upsetting or flat-die forging
• Advantages

– Cheap
– Can form a wide variety of simple shapes with

the same dies

• Squares, cylindrical

– Useful for preparing material for other forms

of forging or machining

– Can handle large items (35 tons)

• Disadvantages

– Barreling of shape due to high friction

Andrzej Matuszak

4

Open Die

Forging

Forging and Cogging

Andrzej Matuszak

5

Open Die

Forging

Force

F = Y

f

 r

2

(1 + 2r/3h)

where Y

f

- For



= 0,5; Y

f

= 590 Mpa

is the flow stress of the material



is the coefficient of friction

r

is the radius

h

is the height of the workpiece

Examples

–

Stainless steel workpiece, 150 mm diameter, 100 mm

high reduced with flat dies to 50% of original height.

Coefficient of friction is 0.2

–

Force is 50 MN

Andrzej Matuszak

6

Forging Methods

Forging Methods

*Open Die *Closed Die

*Other

Open-Die Drop Hammer - Steam Hammer

Andrzej Matuszak

7

Forging Methods

Forging Methods

• Upset forging (heading)

– Grip a bar—heat the end—forge into

desired shape

• Product examples

– Bolts
– Engine valves

Andrzej Matuszak

8

Forging Methods

Forging Methods

Impression Die Drop Hammer Forging

Andrzej Matuszak

9

Forging Methods

Forging Methods

Andrzej Matuszak

10

Forging Methods

Forging Methods

• Press Forging

Andrzej Matuszak

11

Forging Process Categories

Forging Process Categories

Hot

Warm

Isothermal

Slug

Preform

Billet

Heading, Coining,

Cogging, Fullering,

Gathering, Hubbing,

Piercing, Roll Forging,

Skew Rolling

(

skośne walcowanie)

Open die,

Impression Die,

Closed Die,

Precision,

Orbital, Swaging

Trimming,

Machining,

Cleaning

Heat

Treating

Preparation

Forging

Subsequent

Operations

In

sp

e

ct

io

n

Cogging – kucie wstępne, Coining –

prasowanie Heading- zakuwanie,

Hubbing - odciskanie Fullering-

wydłużanie,

Andrzej Matuszak

12

Stages in Impression

Stages in Impression

Die Forging

Die Forging

Andrzej Matuszak

13

Stages in the forging of a

Stages in the forging of a

crank shaft

crank shaft

Kucie matrycowe wstępne

Kucie w wykrojach pomocniczych

Kucie matrcowe
końcowe

Okrawanie

Andrzej Matuszak

14

Terminology of Impression

Terminology of Impression

Forging

Forging

Web- środnik, półka środkowa

Flasz– wypływka

Land – pow. styku

Gutter- pojemnik na

wypływkę

Andrzej Matuszak

15

Closed Die Forging Force

Closed Die Forging Force

F = k Y

f

A

where

Y

f

is the flow stress

A

is the area and

k

is a factor given below

Shapes

k

Simple, no flashing

3-5

simple, with flashing

5-8

Complex, with flashing

8-12

Andrzej Matuszak

16

Hot forging Temperatures

Hot forging Temperatures

Material

Temperature

Range (

o

C)

Aluminum alloys

400-550

Magnesium alloys

250-35-

Copper alloys

600-900

Carbon and low alloy steels

850-1150

Stainless steels

1100-1250

Titanium alloys

700-950

Iron based superalloys

1050-1180

Tungsten alloys

1200-1300

Andrzej Matuszak

17

Forging Machines

Forging Machines

-H

-H

ydraulic

ydraulic

Presses

Presses

Andrzej Matuszak

18

Comparison of Forging

Comparison of Forging

Presses

Presses

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19

Characteristics of Forging

Characteristics of Forging

Processes

Processes

Process

Advantages

Limitations

Open die

Cheap dies

limited to simple shapes

Small quantities

Poor tolerances

Wide range of sizes

Low production rates

Good strengths

high skill required

Closed Die

Good utilization of material

High die costs

Better properties

Machining necessary

Good tolerances and accuracy

High rates

Good reproducibility

Precision

Close tolerances

Machining necessary

Machining unnecessary

High forces

Excellent material utilization

Intricate dies

Thin webs and flanges

Need way of removing part

(złożone
matryce)

Andrzej Matuszak

20

Characteristics of Forging

Processes

Andrzej Matuszak

21

Characteristics of Forging

Processes

Andrzej Matuszak

22

Characteristics of Forging

Processes

Relative production
time as a function of
surface finish
produced by various
manufacturing
methods.