Kim Loai Va Thiet Bi Nhiet

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Transcript of Kim Loai Va Thiet Bi Nhiet

i hc nng -

Trng i hc k thutTS. inh Minh Dim

Gio trnh

Kim loi thit b nhit

nng, 2003

i hc nng -

Trng i hc k thutTS. inh Minh Dim

Tm tt bi ging

Phn 2

c kim loi

nng, 2003

i hc nng -

Trng i hc k thutTS. inh Minh Dim

Tm tt bi ging

Chng 4

Gia cng ct gt kim loi

nng, 2003

i hc nng -

Trng i hc k thutTS. inh Minh Dim

Tm tt bi ging

K thut c kh

nng, 2003

Chng 1: vt liu kim loi 1.1. Tnh cht ca kim loi 1.1.1 Tnh cht ho hc Kim loi l cc nguyn t ho hc pha tri bng tun hon Menelep. Kim loi tham gia cc phn ng vi kim; Cu to nguyn t: lp in t ngoi cng d tch khi ht nhn tr thnh in t t do v nguyn t tr thnh ion dng. Ngoi ra trong thc t ch to cc chi tit my ta cn k n tnh chu n mn, tnh chu nhit , tnh chu a xt, . . . ca kim loi v hp kim ca chng. 1.1. 2 Tnh cht vt l Kim loi l vt liu c nh kim; H s gin n nhit khc nhau; C tnh dn in, dn nhit tt; Khi lng ring () v nhit nng chy ( Tonc ) khc nhau; Kim loi c cu trc mng tinh th ; 1.1. 3 Tnh cng ngh Kim loi c bn, do cao, c kh nng gia cng nng hoc gia cng ngui,... c trng cho tnh cng ngh ca vt liu l : tnh c, tnh rn, tnh hn v tnh gia cng ct gt v nhit luyn (gia cng x l nhit). a. Tnh c Tnh chy long cao (nn kh nng in y lng khun tt); C tnh co ngt khi kt tinh (ng c). Tnh thin tch: S khng ng nht v thnh phn ho hc ca kim loi trong vt c. Tnh ho tan kh b. Tnh rn Kh nng bin dng vnh cu ca kim loi khi chu tc dng ca ngoi lc to nn hnh dng nht nh m khng b ph hu. c. Tnh hn Kh nng to nn mi lin kt khng th tho ri c gi l mi hn. d. Tnh ct gt Kh nng cho php gia cng trn cc my ct gt nh: tin, phay, bo, khoan, mi ... Tnh ct gt ph thuc vo nhiu yu t . V d : Thp t cc bon d ct gt hn thp cc bon cao; Gang xm d gia cng ct gt hn gang trng). e. Tnh Nhit luyn : Kh nng cho php thay i c tnh v mt s tnh cht ca vt liu nh qu trnh x l nhit.1. 2 Phn loi vt liu kim loi (n cht)

Theo mu sc Kim loi en Kim loi mu

: Fe; theo [12] cn c Co, Ni, Mn,... ( mu en xm) : Al, Cu, Pt, Au, ....

1

Theo nhit nng chy Nhit Khi lng ring nng chy oC g/cm3 : 1083 8,93 : 1450 8,90 : 1539 7,87 : 1668 4,51 : 1769 21,45 : 1855 6,51 : 1875 7,19 : 1950 6,02 : 2468 8,57 : 2620 10,2 : 2996 16,65 : 3395 19,35 : 419 7,11 : 232 7,29 : 271,3 9,80 : 327 11,34

Kim loi kh chy T nc

Kim loi d chy

Cu Ni Fe Ti Pt Zr Cr V Nb Mo Ta W Zn Sn Bi Pb

Kim loi nh Kim loi qu Kim loi phng x Kim loi him1.3 kim loi mu :

Be : 1284 1,85 Mg : 650 1,74 Al : 660 2,72 Au : 1063 19,32 Ag : 960 10,5 Pt : 1769 21,45 U : 1133 19,0 Ra (radi), Th (thry) Pu (plutoni), Co,... La, Cs (Xzi), Nd (Ndim), Pr (Prascim) ...

Kim loi mu v hp kim mu l kim loi m hu nh khng c cha st. Kim loi mu thng c cc tnh cht c bit v u vit hn kim loi en : tnh do cao, c tnh kh cao, c kh nng chng n mn, chng mi mn, c tnh dn in, dn nhit tt. Cc kim loi mu thng dng l nhm, ng, titan, manh, thic, vng bc v cc hp kim ca chng. Kim loi mu c th phn loi theo mt s c im sau : 1.3.1 Kim loi nng (c khi lng ring >= 5 g/ cm3) g/ cm3 V d : W = 19,35 cu = 8,94 g/ cm3 Ni = 8,92 g/ cm3 Sn = 7,30 g/ cm3 Zn = 7,14 g/ cm3 1.3.2 Nhm kim loi nh 7 %Al ( 1,3 -1,7 %C, 1,3-1,6 %Si, 0,4-1,0 %Mn, 18-25 %Al) . Lm vic n nhit 900 oC.1.6 Thp v cc ng dng ca n

Thp l hp kim ca st vi cc bon v 1 s nguyn t khc trong thnh phn cc bon : C < 2,14%. Ngoi ra cn c mt s nguyn t khc : Mn, Si,... cc tp cht: S, P, O2, N2, H2 1.6.1 Thp cc bon thng dng (hay cn c tn gi l thp cc bon cht lng thng). Chng c chia thnh 3 nhm ( theo TCVN v tiu chun ca Lin x ) Nhm A - m bo v c tnh ca thp; Nhm B - m bo v thnh phn ho hc (cho php hn) Nhm C - m bo c tnh & thnh phn ho hc, dng cho cc kt cu yu cu v cht lng cao nh kt cu hn;... K hiu theo TCVN 1765 - 75 Thp cc bon : ( ngha ca k hiu : CT - C cc bon, T- thp ) 3 nhm A, B, C K hiu theo TCVN 1675-75 Nhm A CT31 CT33 CT34 CT38 CT42 CT51 CT61 C tnh ca thp nhm A: b KG/mm2 32 32 - 40 34 - 42 38 - 47 42 - 52 50 - 62 60 - 72 ch KG/mm2 22 24 26 28 31 5 K hiu theo TCLX % 22 CT0 33 CT1 31 CT2 21 - 27 CT3 25 CT4 15 - 21 CT5 11 - 16 CT6 10 =14,3 >=13,8 >=13,8 12,9-13,2 11-11,7 12,3-13,2 13-13,3 13,5-13,8 12-13

89,5 91,5 90 87,5 88,5 87,0 82 90 88,5 87 89 89

Nhm TiC-WCT15K6 (WCTi15Co6) T5K10 (WCTiCo10)

Nhm TiC-TaC-WCTT7K12 (WCTTC7Co12) TT10K8 (WCTTC10Co8) TT20K9 (WCTTC20Co9)

Ngoi ra cn c mt s nhm vt liu cng nh sau : Nhm vt liu Ccbon - Nitrit - titan [16](trang 208 ) Khi lng ring 5,6 - 6,2 g/cm3 cng 88 - 93 HRC Gii hn bn un 120 - 180 KG/mm2. Nhm vt liu Ccbt - crm + hp kim cng [16](trang 208 ) Khi lng ring 6,6 - 7,0 g/cm3 cng 80 - 90 HRC Gii hn bn un 40 - 70 KG/mm2. Nhm vt liu khng c vnfram [16](trang 208 ) TIC% TiN% 4Ni1Mo Khi lng ring HRA Gii hn bn un THM-20 79% 21% 5,5 g/cm3. 91 115 KG/mm2. THM-25 74 26 5,7 90 130 THM30 70 30 5,9 89 140 KTHM30A 26 42 32 5,8 88 150 Vt liu bt mi v dng c ct Tc l s dng vt liu c cng hn gia cng vt liu mm hn. Bng 1-2Loi vt liu cng Knoop Gii hn bn Mpa = N/mm2 T nc o C HRA

Kim cng Nitrit Bo ( BN) TiC SiC WC Al2O3 SiO2Thp ti so snh

8000 5000 3100 3000 2700 2100 1000 800

7000 7000 2800 1000 5000 3000 1200 1200

3500 1540 3100 2400 2780 2050

93 82 - 90

17

Vt liu siu cng.[2] (trang 469) Bng 1-3Vt liu Kim cng t nhin Kim cng nhn to Loi n tinh th Loi a tinh th Nitri Bo (BN) Loi n tinh th Loi a tinh th KL ring g/cm3 3,01-3,56 3,48-3,54 3,30-4,00 3,44-3,49 3,30-3,40 cng HV 10.000 8.600 -10.000 8.000 -10.000 9.000-9500 7.000-8.000 Gii hn bn MPa 1900-2100 2000 200-800 500 2000-3000 Nhit gii hn ca bn 600-850 850 700 1200 1400

Vt liu kim cng tuy c cng cao nhng b gii hn bi bn nhit (C nhit gii hn ca bn thp ) Vt liu nitrit bo ( BN ) c cng cao v c tnh bn nhit cao nn thch hp vi gia cng c nh khoan tin, phay, phay, ...

1.9 Cc loi thp khc

1.9.1 Thp lm vic nhit thp [12, 16] trang 498) Chc nng cha v vn chuyn cc loi kh lng, hay vn hnh trong cc iu kin c nhit thp : Ni t lng : - 196 oC xy lng : - 183 oC Hydr lng : - 253 oC Hely : - 269 oC Neon lng : - 247 oC Cc cht kh cc bua hydr ho hi : Butan (-180 oC) Metyl ( - 80 oC) Ni chung khi nhit cng thp th bn cng tng nhng tnh do v nht gim. (Bng 89 page 502 ) Thp 10Cr14Mn14Ni4Ti dn nhit : ( 10

Khng bn

Thp khng g crm Cr13 : X13, 1X13, 2X13, 3X13, 4X13, X14 Cr17 : 12X17, 08X17T, 14X17H2, Cr25-28 : 15X25T, 15X28 Thp khng g Cr-Ni 12X18H8, 17X18H9, 12X18H9T, 12X17, 15X25T, 12X18H9 1.9.4 Thp bn axt [12](trang 497) Chng s n mn ca cc mi trng c hot tnh ho hc mnh. ng dng ch to thp hp ph, ht bm, dng c my lnh, thng cha axt,... Cc loi thp ny dng cha cc cht platic, cht do thu tinh, si thu tinh, cc loi axt vi nng v nhit khc nhau . tng tnh chng n mn trong mi trng axit ngi ta cho thm cc nguyn t : (Mo - Cu), (Cr - Ni - Mo), (Cr - Ni - Mo - Cu), V d : H70M (Ni70MoV) XH65MB (CrNi65MOW)Chng 2 : hp kim chu nhit - bn nhit

2.1 Khi nim chung v thp hp kim chu nhit v bn nhit Khi lm vic nhit cao chi tit chu tc ng ca cc yu t:Nhit , tc dng ho hc ca mi trng; tc dng ca p lc; tc dng ca ng sut;cho nn chng phi c cc yu cu c bit so vi cc loi thp cc bon thng dng. 2.2 Yu cu i vi chi tit khi lm vic nhit cao Phi c tnh bn nhit; gi vng c tnh n nh nhit cao; C kh nng chu ti trng ln To cao; Phi c tnh chu nhit tt: tc l c kh nng chng li s ph hu do n mn ho hc ca b mt vt liu trong mi trng kh nhit cao .2.3 Qu trnh xy ho thp

Thp l hp cht ca st v cc nguyn t khc nh Mn, Si, ... nhit cao st trong thp s tc dng mnh vi xy v to thnh mt lot cc lin kt ho hc nh : FeO, Fe3O4; Fe2O3. Khi To < 570 oC Lp xt c 2 vng: Fe2O3 - Fe3O4 Cu trc tinh th ca chng T oC 110 rt phc tp & tc khuych tn vo trong kim loi rt nh. Khi To > 0 oC - Lp xt cha 3 loi: Fe2O3 - Fe3O4 - FeO. Trong lp FeO 570 l lp xt ch yu, lp ny xp nn O2 d khuych tn vo kim loi. bt u hnh thnh lp oxid FeO; T = 100 oC 570 FeO chim khong 95 % trong thnh phn lp oxid T = >0 750 oC 900 800 700 600 5 Fe + 10 15 20 25 30 Fe + FeO 911 oCFeO FeO + Fe3O4 Fe2O3 + % Fe3O4 O

20

Hnh 2-1 Khi lng b xy ho 10 5

Gin trng thi Fe - O2 i[12] (trang 448) mgToC 1100 900Vng chu nhit km

2 1Vng chu nhit

51 400 500 600 Fe3O4 Fe + 700

700 500

10 C

20

30

%

Hnh 2-2

Hnh 2-3 [12] (trang 450)

bn 30

2

20 10

100

300

500

700

900

T

Hnh 2 - 6 S ph thuc ca bn lu (1000 gi) v nhit ca mt s hp kim (page 456 Guliaev). 1 - HK Mo 2 - HK Ni 3 - HK Co 4 - HK Fe-Cr-Ni-Co 5 - Thp stent 6 - Thp chu nhit 7 - HK Ti 8 - HK AlCh :

Mt s kim loi c nhit lm vic T = (0,7 - 0,8 )Tnc ca KL . Mt s kim loi c nhit lm vic T < 0.5 Tnc ca KL . Tnh bn nhit thay i theo hnh Tnh bn nhit ph thuc cc nguyn t c bn trong hp kim. Nhit cng tng th khong tnh bn hp li (hnh trn) c ngha l nh hng ca cc nguyn t hp kim v ch nhit luyn gim xung. 21

Cc c tnh ca vt liu chu nhit khng th nh gi bng mt thng s m phi kt hp nhiu yu t li vi nhau v cc loi vt liu chu nhit c cc yu cu khc nhau ph hp vi tng loi chi tit my. Loi tuc bin thng lm vic trong 10 nm , lng bin dng 1% Tuc bin kh my bay lm vic trong khong 300 - 3000 gi nn ng sut ln hn loi trn. Tn la vt i dng ch lm vic trong vi pht nhit cao , iu kin lm vic rt khc nghit . Tn la cp 1, cp 2 (v tinh phng ln qu o trong vi giy nn yu cu c bn nhit rt cao)V d

2.4 Cc phng php ho bn nhit cao Nguyn tc chung to ra ra cc vt liu c cu trc l tng ( khng c lch mng tinh th ) hoc to ra mt cu trc c nhiu cn tr cho chuyn ng lch trong mng tinh th chng li bin dng do. Trong thc t c th c mt s phng php ho bn vt liu thp nh sau :2.4.1 Ho bn bng dung dch rn

Khi to dung dch rn mng tinh th b x lch, mi lin kt nguyn t trong mng cng bin i do vy gii hn bn c tng ln . Trng hp to thnh dung dch rn ho tan v hn: L (pha lng) To C nguyn t A L+ t1 < t2

ToC nguyn t B

A 50% Hnh 2-7 Gin