2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$FUNDAMENTALS OF METAL FORMING Overview of Metal FormingMaterial Behavior in Metal FormingTemerat!re in Metal FormingStrain Rate Sen"itivit#Fri$tion an% L!&ri$ation in Metal Forming2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Metal FormingLarge gro! of man!fa$t!ring ro$e""e" in whi$h la"ti$ %eformation i" !"e% to $hange the "hae of metal wor'ie$e"The tool( !"!all# $alle% a die( alie" "tre""e" that e)$ee% #iel% "trength of metal The metal ta'e" a "hae %etermine% the geometr# of the %ie2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Stre""e" in Metal FormingStre""e" to la"ti$all# %eform the metal are !"!all# compressive E)amle"* rolling( forging( e)tr!"ion+owever( "ome forming ro$e""e" Stret$h the metal ,tensile "tre""e"- Other" &en% the metal ,tensile an% compressive) Still other" al# shear "tre""e"2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Material .roertie" in Metal FormingDe"ira&le material roertie"* Low yield strength an% high ductilityThe"e roertie" are affe$te% temperature* D!$tilit# in$rea"e" an% #iel% "trength %e$rea"e" when wor' temerat!re i" rai"e%Other fa$tor"* Strain rate an% fri$tion2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$B!l' Deformation .ro$e""e"/hara$teri0e% "ignifi$ant %eformation" an% ma""ive "hae $hange"1B!l'1 refer" to wor'art" with relativel# low "!rfa$e area to vol!me ratio" Starting wor' "hae" in$l!%e $#lin%ri$al &illet" an% re$tang!lar &ar"2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Fig!re 2345 6 Ba"i$ &!l' %eformation ro$e""e"*,a- rolling2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Fig!re 2345 6 Ba"i$ &!l' %eformation ro$e""e"*,&- forging2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Fig!re 2345 6 Ba"i$ &!l' %eformation ro$e""e"* ,$- e)tr!"ion2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Fig!re 2345 6 Ba"i$ &!l' %eformation ro$e""e"*,%- %rawing2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Sheet Metalwor'ingForming an% relate% oeration" erforme% on metal "heet"( "tri"( an% $oil"+igh "!rfa$e area to vol!me ratio of "tarting metal( whi$h %i"ting!i"he" the"e from &!l' %eformation Often $alle% pressworking &e$a!"e re""e" erform the"e oeration" .art" are $alle% stampings U"!al tooling* punch an% die2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Fig!re 2347 Ba"i$ "heet metalwor'ing oeration"* ,a- &en%ing 2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Fig!re 2347 Ba"i$ "heet metalwor'ing oeration"* ,&- %rawing 2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Fig!re 2347 Ba"i$ "heet metalwor'ing oeration"* ,$- "hearing 2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Material Behavior in Metal Forming.la"ti$ region of "tre""8"train $!rve i" rimar# intere"t &e$a!"e material i" la"ti$all# %eforme% In la"ti$ region( metal9" &ehavior i" e)re""e% the flow $!rve* nK =where K : "trength $oeffi$ient; an% n : "train har%ening e)onent Stre"" an% "train in flow $!rve are tr!e "tre"" an% tr!e "train 2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Flow Stre""For mo"t metal" at room temerat!re( "trength in$rea"e" when %eforme% %!e to "train har%eningFlow stress : in"tantaneo!" val!e of "tre"" reor'ing.erforme% at room temerat!re or "lightl# a&ove Man# $ol% forming ro$e""e" are imortant ma"" ro%!$tion oeration"Minim!m or no ma$hining !"!all# reor'ingBetter a$$!ra$#( $lo"er toleran$e"Better "!rfa$e fini"hStrain har%ening in$rea"e" "trength an% har%ne""Grain flow %!ring %eformation $an $a!"e %e"ira&le %ire$tional roertie" in ro%!$tNo heating of wor' reor'ingDeformation at temerat!re" a&ove recrystallization temperature Re$r#"talli0ation temerat!re : a&o!t one half ofmelting oint on a&"ol!te "$ale In ra$ti$e( hot wor'ing !"!all# erforme% "omewhat a&ove ?4@Tm Metal $ontin!e" to "often a" temerat!re in$rea"e" a&ove ?4@Tm( enhan$ing a%vantage of hot wor'ing a&ove thi" level 2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$>h# +ot >or'ingA/aa&ilit# for "!&"tantial la"ti$ %eformation of the metal far more than o""i&le with $ol% wor'ing orwarm wor'ing>h#A Strength $oeffi$ient i" "!&"tantiall# le"" than at room temerat!re Strain har%ening e)onent i" 0ero ,theoreti$all#- D!$tilit# i" "ignifi$antl# in$rea"e% 2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$A%vantage" of +ot >or'ing v"4 /ol% >or'ing>or'art "hae $an &e "ignifi$antl# altere%Lower for$e" an% ower reor'art geometr# Bariation" in "train rate in %ifferent region" of the artStrain rate $an rea$h 2??? "82or more for "ome metal forming oeration"2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Effe$t of Strain Rate on Flow Stre""Flow "tre"" i" a f!n$tion of temerat!reAt hot wor'ing temerat!re"( flow "tre"" al"o %een%" on "train rate A" "train rate in$rea"e"( re"i"tan$e to %eformation in$rea"e" Thi" effe$t i" 'nown a" strain rate sensitivity 2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Fig!re 234@ ,a- Effe$t of "train rate on flow "tre"" at anelevate% wor' temerat!re4 ,&- Same relation"hi lotte% on log log $oor%inate" 2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$Strain Rate Sen"itivit# Eear" tooling fa"terFri$tion an% tool wear are more "evere in hot wor'ing2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$L!&ri$ation in Metal FormingMetalwor'ing l!&ri$ant" are alie% to tool wor'interfa$e in man# forming oeration" to re%!$e harmf!l effe$t" of fri$tion Benefit"* Re%!$e% "ti$'ing( for$e"( ower( tool wear Better "!rfa$e fini"h Remove" heat from the tooling2002 John Wiley & Sons, Inc.M. P. Groover, Fundamenals o! Modern Manu!acurin" 2#e$/on"i%eration" in /hoo"ing a L!&ri$antT#e of forming ro$e"" ,rolling( forging( "heet metal %rawing( et$4-+ot wor'ing or $ol% wor'ing>or' material/hemi$al rea$tivit# with tool an% wor' metal" Ea"e of ali$ation/o"t