Experimental technique to analyze the influence of cutting conditions on specific energy consumption during abrasive metal cutting with thin discs

Expe imen al echnique o analyze he in luence o cu ing condi ions on speci ic ene gy consump ion du ing ab asi e me al cu ing wi h hin discs Muhammad Rizwan Awan 1 •He na ´n A. Gonza ´lez Rojas 1 •Jose ´I. Pe a Bena ides 2 • Saqib Hameed 1 Recei ed: 13 Janua y 2021 / Re ised: 23 Ma ch 2021 / Accep ed: 9 June 2021 The Au ho (s) 2021 Abs ac Speci ic ene gy consump ion is an impo an indica o o a be e unde s anding o he machinabili y o ma e ials. The p esen s udy aims o es ima e he speci ic ene gy consump ion o ab asi e me al cu ing wi h ul a- hin discs a compa a i ely low and medium eed a es. Using an expe imen al echnique, he cu ing powe was measu ed a ou p ede ined eed a es o S235JR, in e - me allic Fe-Al(40%), and C45K wi h di e en he mal ea men s. The a ia ion in he speci ic ene gy consump- ion wi h he ma e ial emo al a e was analyzed h ough an empi ical model, which enabled us o dis inguish h ee phenomena o ene gy dissipa ion du ing ma e ial emo al. The he mal ea men and mechanical p ope ies o ma e ials ha e a signi ican impac on he ene gy con- sump ion pa e n, i s co esponding componen s, and cu - ing powe . Duc ile ma e ials consume mo e speci ic cu ing ene gy han b i le ma e ials. The speci ic cu ing ene gy is he minimum ene gy equi ed o emo e he ma e ial, and plowing ene gy is ound o be he mos sig- ni ican phenomenon o ene gy dissipa ion. Keywo ds Speci ic cu ing ene gy Speci ic ene gy consump ion Me al cu ing wi h ab asi e disc Ab asi e cu o ope a ion Cu ing in e me allic alloy Fe-Al (40%) 1 In oduc ion The indus ial sec o is cu en ly esponsible o 85% o he wo ld’s ene gy, wi h manu ac u ing accoun ing o 40% o he ene gy used in he indus y [1]. To minimize he en i onmen al impac and educe he p oduc ion cos s, a educ ion o he ene gy consump ion is among he g ea es challenges o he manu ac u ing indus y [2,3]. Machin- ing is one o he mos impo an manu ac u ing echnolo- gies and ep esen s a majo ene gy demand [4]. To educe i s ene gy consump ion, an unde s anding and es ima ion o he ene gy consumed a e he p ima y and impo an s eps [5]. The speci ic ene gy consump ion, ha is, he ene gy equi ed o emo e he uni olume o a ma e ial, is an impo an me ic o e alua ing he ene gy consump ion o machining [6]. In e ms o he speci ic ene gy consump- ion, g inding is one o he mos ene gy-in ensi e p ocesses among o he me al cu ing ope a ions. Du ing g inding, he la ges po ion o he emissions is a ibu ed o he ene gy used o ma e ial emo al [7]. The g inding p ocess, which emphasizes a high ma e ial emo al, is an ab asi e cu o ope a ion, and is he sec ioning o ma e ials wi h hin cu ing discs made o ab asi e pa icles [8,9]. The e o e, a speci ic ene gy analysis o he g inding p ocess in ol ing a high ma e ial emo al is ex emely impo an . The speci ic ene gy consump ion om g inding has h ee componen s: chip o ma ion ene gy, plowing ene gy om he ma e ial de o ma ion, and sliding o ubbing ene gy [10]. Rubbing o sliding is he i s s age o g ain in e ac ion wi h he wo kpiece, and he elas ic de o ma ion occu s du ing his phase wi h a negligible amoun o ma e ial emo al. Wi h he inc ease in o ce, g ain pene- a ion in o he wo kpiece also inc eases, leading o he plowing phase, and bo h elas ic and plas ic de o ma ions occu du ing his phase. Fu he pene a ion o g ain leads &Muhammad Rizwan Awan [email p o ec ed] 1 Depa men o Mechanical Enginee ing, Uni e si a Poli e `cnica de Ca alunya (UPC), Ba celona, Spain 2 Depa men o Elec ical Enginee ing, Uni e si a Poli e `cnica de Ca alunya (UPC), Ba celona, Spain 123 Ad . Manu . h ps://doi.o g/10.1007/s40436-021-00361-2 o he cu ing phase, whe e he ma e ial is plas ically de o med o p oduce chips [11,12]. In his pape , he no a ions P sl ,P pl , and P ch a e used o e e o he powe consumed by he h ee mechanisms men ioned abo e, ha is, sliding, plowing, and cu ing ene gy, espec i ely. Va ious ac o s such as he ab asi e sha pness, ma e ial p ope ies, and p ocess pa ame e s go e n he ansi ion o ene gy consump ion beha io among hese h ee s ages and ha e been ex ensi ely discussed. Acco ding o Rowe [13], ubbing o sliding is he p edominan o m o ene gy in ma e ial emo al o p ocesses such as polishing and lap- ping, whe eas p ecision g inding occu s in all h ee egimes. High-ene gy deep g inding and cu -o ope a ions ake place p edominan ly in he ma e ial emo al egime h ough a chip o ma ion o duc ile ma e ials o h ough a c ack o ma ion o b i le ma e ials. Na ´poles e al. [14] de eloped a ma e ial emo al a e model o e alua e he speci ic ene gy consump ion du ing indus ial-scale g ind- ing o C45K wi h di e en he mal ea men s and AISI 304. I was demons a ed ha he sliding ene gy was he main o m o ene gy dissipa ion and dec eased wi h an inc ease in he dep h o he cu . Masoumi e al. [15] in es iga ed he ma e ial emo al beha io du ing su ace g inding o a high- eloci y oxy- uel (HVOF) he mally sp ayed WC-10Co4C coa ing. The esul s e ealed ha ma e ial emo al was due o bo h a b i le ac u e and duc ile low modes depending on he g inding pa ame e a ia ion, and a la ge amoun o ene gy was dissipa ed by a plas ic de o ma ion om he plowing. Simila ly, Singh e al. [16] ound a speci ic plowing ene gy o be he mos signi ican componen a lowe eed a es o he g inding o ha d and high-s eng h ma e ials. Shaw [17] demon- s a ed ha li le ene gy was ca ied by he chips when conduc ing inish and o m g inding (FFG), whe eas wi h s ock emo al g inding (SRG), mos o he speci ic ene gy was consumed as he shea cu ing ene gy o p oduce chips. Acco ding o Malkin and Joseph [18], a ex emely high ma e ial emo al a es, he sliding and plowing ene gy became negligible, and he minimum ene gy was equal o he speci ic chip o ma ion ene gy. The minimum ene gy equi ed o o m he chips is cons an , and a highe emo al a es, i is he only dominan ene gy [6]. Con a y o many di e en s udies on he speci ic ene gy o FFG, he speci ic ene gy consump ion o an ab asi e cu o ope a ion wi h hin cu ing discs o me als has a ely been discussed. In an ea lie s udy, Shaw e al. [19] analyzed he in luences o he eed a e on speci ic ene gy consump ion and cu ing o ces in an ab asi e cu o ope a ion o s eel and aluminum. They used a cu ing disc wi h a la ge diame e (508 mm) and an ex emely high eed a es (3.39–12.7 mm/s) o he expe imen . The esul s e ealed ha he cu ing o ces inc eased wi h an inc ease in he eed a e up o some ex en and hen dec eased om he end line. The speci ic ene gy consump ion dec eased wi h an inc ease in he eed a e, howe e , his s udy did no explain he h ee speci ic ene gy componen s o ub- bing, plowing, and cu ing du ing ma e ial emo al. Tu che a [20] in es iga ed he cu ing condi ions ha a ec ed he cu ing o ce and cu ing ene gy in s one cu - ing using diamond cu ing disks. The au ho showed ha he cu ing ene gy dec eased wi h an inc ease in he dep h o he cu and he eed a e, howe e , he cu ing o ce inc eased wi h an inc ease in he equi alen chip hickness. The adop ed model o he speci ic ene gy in his s udy did no explain he ma e ial emo al phases and hei co e- sponding ene gy componen s. In all p e ious s udies measu ing he speci ic ene gy consump ion om he g inding and ab asi e cu ing o me al, s one, and op ical glass [6,19–22], he cu ing powe (P) is measu ed in e ms o he angen ial o ces (F ) and cu ing eloci y (V c ) o he disc, and shown as P¼F Vc:ð1Þ This s udy aims o in oduce an al e na i e me hod o di ec ly measu e he cu ing powe o a speci ic ene gy e alua ion o an ab asi e cu o ope a ion. This me hod- ology uses a combina ion o analy ical me hods and spe- cially designed and manu ac u ed equipmen o au oma e he mo emen o a s anda d g inde a di e en eed a es. In addi ion, pa icula ly in s udies o ab asi e cu ing ope a ions, he speci ic ene gy has no been dis inguished in o h ee modes du ing ma e ial emo al [19,23]. How- e e , in his esea ch, he speci ic ene gy measu ed h ough an al e na i e me hod is ca ego ized in o h ee modes, i.e., sliding, plowing, and cu ing, using an empi ical model. These h ee componen s used in g inding ha e been dis- cussed in he li e a u e e iew because g inding also in ol es me al cu ing wi h ab asi e discs and has been ex ensi ely discussed and analyzed. The esea ch p esen ed below will help unde s and how he ma e ial p ope ies and cu ing condi ions a ec he beha io o he speci ic ene gy consump ion du ing he ma e ial emo al. 2 Ma e ials and me hodology 2.1 Wo kpiece ma e ial and cu ing ool The ma e ials used in his expe imen we e S235JR, C45K, and e ous aluminum-based in e me allic alloy FeAl (40%) wi h a chemical composi ion o 60% Fe and 40% Al [24]. C45K was s udied in h ee di e en s a es: no mal C45K condi ion, C45K wi h quenching (C45K-Q), and C45K wi h quenching and empe ing (C45K-Q?T). The chemical composi ions o S235JR and C45K a e lis ed in Table 1[25,26]. M. R. Awan e al. 123 The ha dness o ma e ials (HRB) gi en in Table 2is measu ed using a Rockwell ha dness es e (de eloped by Wilson) wi h an inden e load o 100 kg. The ab asi e cu ing ac ion is conduc ed using an ul a- hin s eel cu ing disc wi h a 1 mm hickness, 22 mm bo e diame e , and 115 mm ou e diame e moun ed on a 600 W Ryobi g inde . The echnical cha ac e is ics o he cu ing disc a e de ined by he code 41 99A 46 S7 BF gi en in he ca alog [27]. The i s digi code 41 indica es he manu ac u e symbol; 99A indica es ha he ab asi e ma e ial is made o aluminum oxide; 46 indica es a medium ha d g ain size; S7 is he ha dness; and BF ep esen s a ype o esin used o bonding. The ab asi e ma e ial o he cu o disc wi h a coa se g ain size and high ha dness enables a as cu ing [28,29]. 2.2 Me hodology The speci ic ene gy consump ion is he powe equi ed o emo e he uni olume o ma e ial, and i s alue (V SEC )is de ined as he a io be ween he powe consumed and he ma e ial emo al a e, and shown as [6] VSEC ¼Pm Qw ;ð2Þ whe e P m is he mechanical cu ing powe , and Q w is he ma e ial emo al a e. To measu e he mechanical cu ing powe , wo di e en expe imen al se ings we e applied du ing he p ocess, as shown in Fig. 1. In he i s se ing, as shown in Fig. 1a, he s anda d angle g inde was coupled wi h a dynamome e o measu e and de e mine he ela- ionship be ween he mechanical powe and elec ical powe consumed unde di e en loading condi ions. The Hys e esis Dynamome e , model HD-710-BNA, de eloped by Mag ol, USA, was used o his expe imen . A high- speed p og ammable con olle a ached o he dynamome e displays he measu emen o mechanical cha ac e is ics such as o que, mechanical powe (P m ), speed o o a ion ( /min), and elec ical cha ac e is ics such as he e ec i e elec ic powe (E e ) and ol age. The a e age o e ec i e elec ic powe E e is he amoun capable o ans o ming he elec ical ene gy in o wo k. Pa o he dynamome e equipmen measu es he e ec i e elec ic powe . This de ice does his by mul iplying he cu en and ol age ins an aneously using a 4-quad an mul iplie , and hen a e ages he ins an aneous powe signal. The mechanical powe (P m ) is de ined as he p o- duc o he o que and angula eloci y. The ela ionship be ween he mechanical powe (P m ) deli e ed by he g inde and he e ec i e elec ic powe (E e ) consumed by he mo o is shown in Fig. 2. Pm¼2:4Ee742:61:ð3Þ The beha io o his eg ession cu e is associa ed wi h he g inde used and is he e o e an expe imen al esul o he beha io o he equipmen used. The end line be ween hese wo pa ame e s is linea . Equa ion (3) is a eg ession equa ion o his end line, and 2.4 deno es he slope o he line. Equa ion (3) ob ained h ough his g aph is pa icula o his g inde and can be used o de e mine he mechanical powe du ing me al cu ing wi h an ab asi e disc o epe i i e expe imen s. Using he eg ession equa ion o measu e he mechanical powe h ough he elec ical ene gy consumed du ing ab asi e cu ing wi h a disc elimina es he need o measu e he cu ing o ce and cu ing eloci y o speci ic ene gy es ima ion. In he second s ep, a s anda d angle g inde is moun ed on he expe imen al con igu a ion, which has been speci ically designed and manu ac u ed o moun and ope a e he s anda d disc g inde a a ious eed a es o he me al ab asi e cu ing ope a ion s udied he ein. Figu e 1b illus a es he di e en pa s o he equipmen de eloped o his s udy. An ul a- hin disc o 1 mm, moun ed on he angle g inde , ac ed as a cu ing ool o machine he me allic ba s. The s eppe mo o ope a es he machine a ou di e en eed a es de ined by he po en iome e . The LED ligh s we e used as indica o s o ou de ined speeds. Two e ical sepa a e bu ons we e placed o he clockwise and an iclockwise mo emen o he s eppe mo o , which e en ually mo ed he machine up and down. A schema ic diag am o he elec ical componen s inside a wooden box is shown in Fig. 3. Owing o machine equi emen s o highe accu acy in mo emen , posi ion- ing, and a ying o que in dynamic loading, a s eppe mo o was selec ed [30]. The speed, mo emen , and di ec ion o he s eppe mo o in ela ion o he inpu eed a e we e p og ammed using he A duino Uno mic ocon- olle . The s eppe mo o d i e TB6600 con ols he cu - en be ween he s eppe mo o and con ol ci cui in mic o- Table 1 Chemical composi ion o me allic alloys Me allic alloys C Mn P S Si Ni C C45K 0.5 0.50–0.90 0.03 0.04 0.40 0.40 0.40 S235JR 0.22 1.60 0.05 0.05 0.05 Table 2 Ma e ial ha dness Me allic alloys HRB C45K 100.20 C45K-Q 120.60 C45K-Q?T 85.85 S235JR 80.05 In e me allic 100.20 Expe imen al echnique o analyze he in luence o cu ing condi ions on speci ic ene gy consump ion… 123 s eps. The eed a e ange can be changed by changing he numbe o s eps in he d i e. G inde bu ons, eme gency s op bu ons, and limi swi ches a e con olled h ough a swi ch elay. Limi swi ches a e p og ammed wi h a mic ocon olle , which s ops he s eppe mo o once he mo emen eaches he maximum upwa d o minimum downwa d limi on he lead sc ew. The powe sou ce is used o s ep he inpu ol age supply down o 12 V o he s eppe mo o d i e and o he unc ions. The elec ical ene gy consumed by he machine du ing he cu ing o ope a ion is measu ed using a powe ana- lyze a di e en eed a es, which is s o ed in a compu e h ough a channel eco de . Using hese elec ical ene gy Fig.1 Expe imen al se up o measu e he mechanical powe and speci ic ene gy consump ion M. R. Awan e al. 123 alues, he co esponding alues o he mechanical powe a e calcula ed using he eg ession line in Eq. (3). To measu e he ma e ial emo al a e in Eq. (2), a gene al model o he ma e ial emo al a e o his expe - imen has been used, which is he p oduc o he eed a e and cu ing c oss sec ion [31], and shown as Qw¼AcV ;ð4Þ whe e V is he eed a e, and A c is he cu ing c oss-sec ion. V in Eq. (4) is a unc ion o he o a ional speed o he s eppe mo o . A kinema ic s udy o he spa ial mo emen o he cen e poin , whe e he cu ing disc was moun ed, was ca ied ou using gene alized coo dina es [32]. The kinema ic s udy showed ha gi en a cons an o a ion speed o he s eppe mo o , he eed a e a he cu ing poin was e ical and emained cons an h oughou he cu ing c oss sec ion. The eed a e alues ob ained om he kinema ic s udies we e e i ied by he ime aken o he cu ing discs o cu h ough he leng h o he wo kpiece. The cu ing c oss-sec ion A c , shown in Eq. (4), is pe pen- dicula o he eed a e, and is de ined by he p oduc o ma e ial hickness ‘‘b’’ and wid h o cu ing hickness ‘‘a’’, as shown in Fig. 4. The wid hs o he specimens we e 3, 10 and 4.6 mm o S235JR, C45K, and in e me allic Fe-Al (40%), espec i ely, and he cu ing hickness was 1.8 mm. The cu ing hickness was ound o be highe han ha o he cu ing disc. I was e i ied ha he ac ual hickness o he cu ing did no coincide wi h he in o ma ion p o ided by he manu ac u e o a 1 mm hick cu ing disc. I was also de e mined ha an axial de ia ion o he cu ing disc occu ed when o a ed unde ee cu ing condi ions. The eed a es used in his expe imen we e high o hese ypes o discs. The e o e, du ing he ma e ial cu ing, a u he bending and ib a ion o he cu ing disc inc eased he cu ing hickness. 2.3 Measu emen o expe imen al da a The elec ical ene gy consumed du ing he p ocess was measu ed wi h an analog powe analyze buil wi h an AD633 chip, which p o ided he ins an aneous p oduc alues o he cu en and ol age. A channel eco de logge Velleman K8047 connec ed o a compu e allows collec ing he powe signal wi h a sampling equency o 0.01 s. Figu e 5shows he powe cu e o a cu ing expe imen on S235JR ma e ial wi h V a 1.488 mm/s. The beha io obse ed du ing all expe imen s was simila and could be di ided in o h ee s ages. The i s s age co esponds o he ene gy consump ion when he disc is no cu ing. The second s age is he ansi ion s age in which cu ing begins, cha ac e ized by a apid inc ease in he cu ing powe . The hi d s age is he s abiliza ion s age o he powe consump ion. The a e age powe consumed du ing he las s age, E e , is used o es ima e he speci ic ene gy consump ion. Using he eg ession in Eq. (3), P m is ob ained as a unc ion o he measu ed E e . The cu ing hickness o each specimen was measu ed using a WADEO iT33-MDUK digi al mic oscope wi h a 2 Mega pixel image senso . The hickness was measu ed using Image J2 open- sou ce so wa e o a scien i ic image analysis, de eloped by he Uni e si y o Wisconsin-Madison. The wid h o he specimen was measu ed wi h a digi al e nie calipe . The Fig. 2 Mechanical powe e sus elec ical ene gy Fig. 3 Schema ic diag am o elec ical ins umen s Fig. 4 Cu ing c oss sec ion Expe imen al echnique o analyze he in luence o cu ing condi ions on speci ic ene gy consump ion… 123 equipmen allowed he selec ion o ou di e en eed a es p e iously se a 0.539, 0.613, 0.899 and 1.488 mm/s. Owing o he p obabili y o a lack o uni o mi y in he g ain alignmen o he wo kpiece ma e ial and cu ing disc, and a small la e al ib a ion o he cu ing disc a lowe eed a es, a small change in he ma e ial emo al a e was ound o he same eed a e. To compensa e o his, he cu ing expe imen was epea ed ou imes o each eed a e. The sliding powe (P sl ) was measu ed h ough a sepa a e expe imen , as shown in Fig. 6. The cu ing disc is engaged wi h he wo kpiece ma e ial a a speci ic eed a e. When he cu ing disc eached he middle o he cu ing pa h and he powe consump ion was s abilized, he eed a e was s opped a poin A, wi h he cu ing disc main ained in he unning condi ion. S opping he eed a e p oduced a sud- den d op in powe , which was again s abilized a poin P. This ope a ion kep he cu ing disc in con ac wi h he ma e ial wi hou chip emo al and wi hou p oducing a plas ic de o ma ion. The powe measu ed a he in e sec- ion poin P o eg ession lines BC and DE was only associa ed wi h he sliding phenomenon. 2.4 Cu ing model The cu ing model is based on he ac ha he mechanical powe consumed by cu ing (P m ) is equal o he summa ion o he powe consumed by sliding (P sl ), powe consumed by plowing (P pl ), and powe consumed by he chip o - ma ion (P ch ), and shown as Pm¼Psl þPpl þPch:ð5Þ The ela ionship be ween he speci ic cu ing ene gy and ma e ial emo al a e shown in Figs. 7and 8is es ima ed by he empi ical model, and shown as PmPsl Qw ¼Ppl Qw þVSCE:ð6Þ The model p esen ed in Eq. (6) was p oposed by Gu owski e al. [33] and la e alida ed by Ka a and Li [34] based on expe imen al esul s. The adop ed model demons a ed s a is ical accu acy in e alua ing he speci ic ene gy consump ion wi h espec o he ma e ial emo al a e o he p ocesses o g inding, milling, u ning, and injec ion molding [35]. The expe imen al alues o speci ic ene gy consump ion o he C45, in e me allic Fe-Al(40%), and S235JR a e shown in Figs. 7and 8, espec i ely. This was e i ied h ough he p oposed model in Eq. (6). The powe s dissipa ed by P sl ,P pl and speci ic cu ing ene gy o a ma e ial a e cons an , as shown in Table 3. These con- s an alues o P pl and speci ic cu ing ene gy a e he coe icien s o Eq. (7) and used o d aw he expe imen al g aphs in Figs. 7and 8. These coe icien s we e ob ained by adjus ing he expe imen al da a using he leas squa es. Figu es 7and 8indica e ha he beha io o his model is asymp o ic. Wi h an inc ease in he ma e ial emo al a e, he a io o P pl o Q w dec eases, and a an ex emely high ma e ial emo al a e, he plowing ene gy educes signi i- can ly. The educ ion in he plowing ene gy in e ms o Fig. 5 Elec ical ene gy consump ion beha io Fig. 6 Sliding powe measu emen o C45K-Q?T M. R. Awan e al. 123 pe cen age is also shown in Fig. 10. The educ ion o plowing ene gy wi h he ma e ial emo al a e is in ag eemen wi h p e ious esea ch on g inding [6,14]. The sliding powe depends on he o a ional speed o he cu ing disc. In his expe imen , he o a ional speed o he cu ing disc is cons an and unde goes an ex emely small change depending on he eed a e. The e o e, he sliding powe emains cons an . The eg ession applied o he expe i- men al da a o he ma e ials has coe icien s o eg ession R 2 g ea e han o equal o 0.872. The coe icien o de e mina ion, close o uni y o mos o he ma e ials, shows a good i be ween Eq. (6) and he expe imen al da a o he speci ic ene gy consump ion. 3 Resul s and discussion A single ac o one-way analysis o a iance (ANOVA) was applied o he mean speci ic ene gy alues o he ou eed a es, as shown in Table 4. The a ia ions in he mean alues o he speci ic ene gy consump ion we e s a is ically signi ican (P alues o less han 0.05) o mos o he ma e ials. The e o e, he eed a es used o p oduce di - e en ene gy consump ions do no belong o he same amily o cu ing condi ions. In gene al, o all ma e ials, he speci ic ene gy con- sump ion dec eases asymp o ically wi h an inc ease in he ma e ial emo al a e, which con i ms he accu acy o he adop ed me hodology. I is e iden om he g aphs in Figs. 7and 8 ha , a an ex emely small ma e ial emo al a e, he speci ic ene gy consump ion is qui e high. This phenomenon is known as he size e ec [6]. Wi h an inc ease in he ma e ial emo al a e, he speci ic ene gy consump ion dec eases. Because he speci ic ene gy con- sump ion o a ma e ial de o ma ion has a cons an alue, Fig. 7 Speci ic ene gy consump ion ela ionship wi h ma e ial emo al a e o C45K, C45K-Q?T, C45K-Q Fig. 8 Speci ic ene gy consump ion ela ionship wi h ma e ial emo al a e o aS235JR and bin e me allic Fe-Al(40%) Table 3 Asymp o ic pa ame e alues and sliding powe Ma e ials P sl / (Js -1 ) P pl / (Js -1 ) VSEC / (Jmm -3 ) R 2 S235JR 29.16 163.69 37.50 0.956 In e me allic- FeAl(40%) 77.36 113.19 13.08 0.878 C45K-Q 99.36 228.04 7.82 0.912 C45K-Q?T 117.36 216.21 4.93 0.923 C45K 127.36 152.18 4.16 0.872 Expe imen al echnique o analyze he in luence o cu ing condi ions on speci ic ene gy consump ion… 123 his dec ease in he speci ic ene gy consump ion is only due o he dec ease in he plowing ene gy ( Ppl Qw). Thus, a a highe s ock emo al a e, he speci ic ene gy consump ion is educed o he minimum alue. This minimum ene gy is he speci ic cu ing ene gy, which emains cons an h oughou he en i e cu ing p o- cess, as con i med by Malkin and Guo [6]. Acco ding o Shaw [17], in he s ock emo al g inding p ocess, mos o he ene gy was dissipa ed as he shea cu ing ene gy equi ed o p oduce he chips. Howe e , he au ho con- duc ed an ab asi e cu ing o ope a ion a ex emely high eed a es (5–60 /min o 2.1–25.4 mm/s) [19]. The dom- inance o he shea cu ing ene gy in hei expe imen s was a ibu ed o he use o ex emely high eed a es. The ange o eed a es du ing his expe imen (0.5–1.488 mm/s) is low in compa ison o he eed a es used by Shaw [17]. The gi en eed a es a e suppo ed by he g inde used, and eed a es highe han his ange s opped he cu ing machine. Lowe eed a es allowed he cu ing disc o su icien ly de o m he ma e ial be o e b eaking, which was he eason o he dominance o he plowing ene gy and he low speci ic cu ing ene gy. Figu e 7shows he ela ionship be ween he speci ic ene gy consump ion and he ma e ial emo al a e o he h ee ma e ials o no mal C45K and C45K wi h di e en he mal ea men s. C45K-Q shows he highes speci ic ene gy consump ion wi h he highes ha dness, ollowed by C45K-Q?T wi h he lowes ha dness. C45K has he lowes speci ic ene gy consump ion among he h ee ma e ials, al hough i s ha dness is highe han ha o C45K-Q?T. The speci ic ene gy consump ion o hese h ee ma e ials and hei co ela ion wi h he ma e ial ha dness exhibi a di e en end om he p e ious esea ch conduc ed by Na ´poles e al. [14] on he same ma e ials o su ace g inding. The mal ea men signi ican ly a ec ed he speci ic ene gy consump ion and speci ic ene gy con- sump ion o he ma e ials. The speci ic ene gy consump- ion o C45K-Q s eel is he highes among he h ee specimens o C45K owing o i s high ha dness. Ma inescu e al. [36] epo ed ha an inc ease in ha dness inc eased he esis ance o ab asi e machining, he eby inc easing he cu ing o ces and machining di icul y. C45K empe ed s eel consumes a highe speci ic ene gy compa ed wi h C45K despi e he low ha dness owing o he empe ing conduc ed o educe he ha dness and inc ease he ough- ness and duc ili y o he ma e ial [37]. An inc ease in oughness inc eases he ene gy equi ed o de o m he ma e ial [38]. The h ee ma e ials show he same end o dec ease in he speci ic ene gy consump ion. Howe e , o quenched and empe ed s eel, a a high ma e ial emo al a e, he machine did no p o ide an accu a e ep esen a ion o he ene gy consumed, and he cu ing disc was jammed in o he wo kpiece. This indica es ha he mal ea men has a conside able e ec on he machinabili y o he ma e ials. I also shows ha his cu ing disc has limi a ions o speci ic ma e ials unde ce ain cu - ing condi ions. The mal ea men o C45K also a ec s he speci ic cu ing ene gy. As shown in Table 3, C45K, C45K- Q?T, and C45Q exhibi conside able di e ences in he alues o speci ic cu ing ene gy. Howe e , acco ding o Malkin and Joseph [18], he minimum ene gy equi ed o p oduce chips in he ab asi e p ocess is una ec ed by alloying o hea ea men . Thus, he di e ence in he speci ic cu ing ene gy owing o he hea ea men o C45K used in his expe imen is no in ag eemen wi h Re . [18]. Among he me allic alloys, S235JR, which has he lowes ha dness, had he highes speci ic ene gy con- sump ion and speci ic cu ing ene gy, as shown in Fig. 8a. The ca bon con en o S235JR is compa a i ely lowe among specimens, and low ca bon s eel is mo e duc ile. Thus mo e ene gy is equi ed o machine he low-ca bon s eel in compa ison o he medium-ca bon s eel and is compa a i ely di icul o machine [39]. In compa ison o b i le ma e ials, duc ile ma e ials unde go ex ensi e plas- ic de o ma ion be o e ac u e [40]. A la ge amoun o plas ic de o ma ion in duc ile ma e ials equi es a high speci ic ene gy o ac u e he ma e ial [41,42]. The e o e, he high alues o speci ic ene gy consump ion and speci ic ene gy consump ion o S235JR a e a ibu ed o a la ge plas ic de o ma ion owing o a high duc ili y. The speci ic ene gy consump ion beha io o he in e - me allic Fe-Al(40%) is shown in Fig. 8b. The ha dness o me allic Fe-Al(40%) is he same as ha o C45K, and i s speci ic ene gy consump ion ela ionship wi h ma e ial emo al ollows he same end as ha o he no mal C45K. C45K is b i le owing o i s highe ca bon con en . The same end o expansion is a ibu ed o he b i le na u e o he in e me allic Fe-Al (40%). The b i le ac u e o in e me allic ma e ials is due o weak g ain bounda ies and he highe concen a ion o aluminum, which limi s he duc ili y o he ma e ial [24,43,44]. Howe e , he speci ic Table 4 One way ANOVA Sou ce SS d MS FP- alue F- c i ical C45K 326.49 3 108.8 75.784 3.68 9 10 -5 4.757 C45K- Q?T 147.3 2 73.65 4.4783 0.06456 5.143 C45K-Q 343.13 2 171.6 26.736 0.001027 5.143 Fe- Al(40%) 941.94 3 314 24.823 0.000418 4.347 S235JR 80.468 3 26.823 57.243 9.49 9 10 -8 3.411 M. R. Awan e al. 123 ene gy consump ion o in e me allic Fe-Al (40%) is highe han ha o he C45K no mal and wi h he mal ea men . As shown in Table 3, he speci ic cu ing ene gy o in e - me allic Fe-Al (40%) in pe cen age o o al ene gy is highe han ha o no mal C45K and wi h he mal ea - men . This indica es he compa a i ely sligh ly highe duc ili y o in e me allic Fe-Al(40%), which is he eason o he high speci ic cu ing ene gy. Saigal and Yang [45] also epo ed highe cu ing o ces o i on aluminides in compa ison o medium-ca bon s eel o milling ope a ions. Figu e 9shows a compa ison o he sliding powe pe uni o cu ing a ea o all ma e ials. The expe imen esul s in Fig. 6show ha he sliding ene gy does no pa icipa e in he ma e ial emo al p ocess and is me ely a ubbing o ic ion ene gy. Fo his eason, sliding powe pe uni o cu ing a ea was used by Zhang e al. [46] and Linke e al. [47]. The highes alue o he sliding powe pe uni cu ing a ea o in e me allic Fe-Al(40%) was due o i s b i le na u e a no mal empe a u es. The sliding o ubbing powe is dissipa ed du ing he ini ial con ac o he cu ing g ain wi h he ma e ial, and does no p oduce a ma e ial de o ma ion. B i le ma e ials do no unde go any plas ic de o ma ion be o e a ac u e [31]. The e o e, he high sliding powe o in e me allic Fe-Al(40%) is due o he ini ial ubbing ene gy being abso bed by he ma e ial wi hou p oducing plas ic de o ma ion. Wu e al. [48] p esen ed a model ha also p o ided some suppo o his a gumen , which s a ed ha , in he g inding o b i le ma e ials, he main o ms o ene gy dissipa ion we e ub- bing and chipping. S235JR has he highes duc ili y among he gi en ma e ials, and duc ile ma e ials end o unde go signi ican plas ic de o ma ion p io o a ac u e [40]. The e o e, he plas ic de o ma ion o S235JR s a s ex e- mely ea ly, which is he eason o he e y low sliding powe dissipa ion pe uni cu ing a ea. The C45K amily has a lowe duc ili y han S235JR owing o i s highe ca bon con en , which is he eason o he compa a i ely highe sliding ene gy pe uni o he cu ing a ea. Wi hin he C45K amily, C45K-Q has he highes ha dness, which inc eases he b i leness, and hus, he sliding powe pe uni o he cu ing a ea inc eases. C45K-Q?T has less sliding powe pe uni o cu ing a ea han C45K because o he he mal ea men . As he empe ing educes he ha d- ness and inc eases he duc ili y o he ma e ial, he sliding powe pe uni o cu ing a ea is educed. To de e mine he pe cen age o con ibu ion o he speci ic ene gy componen s o ma e ial emo al, he ba cha shown in Fig. 10 was d awn. The sliding ene gy is no shown in his g aph because i me ely ubs and does no de o m he ma e ial. Fo all ma e ials, in gene al, he speci ic plowing ene gy has been ound o be he mos signi ican phenomenon in he o al speci ic ene gy con- sump ion. The dominance o he plowing ene gy o hese ma e ials is due o he use o a compa a i ely low eed a e o his expe imen . The con ibu ion o he plowing ene gy in e ms o he pe cen age is highe o he C45 K amily o ma e ials because o hei high ha dness alues. E en a high eed a es, plowing ene gy emained he mos domi- nan phenomenon, wi h 68%, 79%, and 73% o C45K, C45K-Q?T, and C45K-Q, espec i ely. The dominance o he plowing ene gy in ha d and high-s eng h ma e ials has also been de e mined o g inding [16,49]. The con ibu- ion o speci ic ene gy consump ion in e ms o pe cen age was compa a i ely highe o S235JR a highe eed a es. Owing o he low ha dness alue o S235JR, he ansi ion om elas ic o plas ic de o ma ion becomes easie a highe eed a es, which apidly educes he plowing ene gy. The cu ing powe depends on he ma e ial p ope ies and eed a e. The ela ionships be ween he cu ing powe and he eed a es o C45K and S235JR a e shown in Fig. 11. As indica ed in Fig.11, he cu ing powe inc eases wi h an inc ease in he eed a e; howe e , a a ce ain highe eed a e, he inc ease in cu ing powe educes and he cu e ends o la en. A high eed a es, he cu ing g ains become sha pe and consume less powe o me al cu ing; hence, he cu ing o ce dec eases. This beha io is analogous o he esea ch indings o Shaw [19] on ab asi e cu o ope a ions. The cu ing powe ela ionship wi h he eed a e o in e me allic Fe-Al(40%) did no ollow he gene al end. As shown in Fig. 11, he cu ing powe a a high eed a e did no dec ease and inc eased o a highe alue. This inc ease in cu ing powe is a ibu ed o an inc ease in he duc ili y o he ma e ial owing o he high empe a u e encoun e ed a high eed a es. A high eed a es, an inc ease in empe a u e inc eases he yield s ess; hence, he duc ili y o in e me allic Fe-Al(40%) inc eases Fig. 9 Compa ison o sliding powe pe uni o cu ing a ea o all ma e ials Expe imen al echnique o analyze he in luence o cu ing condi ions on speci ic ene gy consump ion… 123