Question

A 2.00” diameter billet will be reduced in diameter to 1.00” using direct extrusion as shown below. The strength coefficient and strain hardening exponent of the material are K = 60,000 lb/in2 and n = 0.18. The coefficients for Johnson’s strain formula are a = 0.8 and b = 1.5. The ram force available on the extrusion press is 1.75 X 10^6 lb. Calculate the maximum length (Lmax) of billet that can be extruded.

Container Ram Final work shape F Die Work billet 1.00" diameter 2.00" diameter Lmax

Answer 1

Conlainn D F S Ja die (Caren) Di= a (Initred Diameten) Da 1" (Final Diameten) Ram forca on Extrusion Pyucu 125x106 lb Go, ou o db ince (Strength Coellient) 0:18 (Strain handening Emponend) Emison Ratio Ai (Area Initial ) Cross-sechiralarna Ao (Anea. Final) of Bled Ideal Reformation redundant worke" OCCU) with no friction and The strain in eatrusion life in ) - Inland) In [2 x (212 *(! 1.386 work the Trichon exists blu bilent the Die and the Squizzes down and passes Passes through die opening. In Direed Extrusion Friction also exists blw the Container wall and the billet Surface.

The following empenical Ran proposed by Johnson estimating extrusion strewn (in bichin Condition ) lan= at bola aj Ene Extrusion strain 62 4.5 (hinen) Average Flow stress during Deformation, kan (tn) {= tru sdreuth =1.386 GU.Ovo *(1-38699 1 to 18 - 53924.56 16 in 2 En= at bila = 0.8+5. In [Ax{21] [12x(11? 2.879 Causes In Direct extrusion the effect of frichon blu the Confernen walls and the billet the Ram Pressure to be Chreater than for Indirect Extrusion. In Dire of exhesion, Ram Pressure can be computed by P = 5 (enter De P-1-0

Ere La rema to Extrusion strain Portion of the billet lingth maining be extruded Original Diameten of billet Da Crinen Pore. 1.75×106 lb p 1.75x10 6 12x (2 12 3.141 n=3.141 = 0.557X106 16 in 2 From (al eqi P:(inter) P (sna 21879) 0.557 X 106 53924.56 ( 2.879 + 2 Lomax Ilymus ] 10.331 2.879 + Lemax Lmax= 7.452" or 7.452 inch In Extrusion Process (Direct) Large Pressure is applied initially, As to overcome friction in large length inside the Container and Pressure get reduces antill it get fully extruded P = (enta +2) PT = 7.452" as given in formula. As L Lmax