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BI GING CNG NGH CH TO MY
H ni, 1/2015
TS. Trng c Phc
B mn Cng ngh ch to my
Vin C kh - HBKHN
T1
Sch gio trnh
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
Gio trnh Cng Ngh Ch To My
Chng 1. Nhng khi nim c bn
Chng 2. Cht lng b mt gia cng
Chng 3. chnh xc gia cng
Chng 4. Chun
Chng 5. Lng d gia cng
Chng 6. Tnh cng ngh trong kt cu
Chng 7. Chn phi v gia cng c/b phi
Chng 8. Cc phng php gia cng ct gt
Chng 9. Gia cng tinh bng b/dng do
Chng 10. Cc phng php gia cng khc
Chng 11. Gi thnh sn phm
Chng 12. Tiu chun ha qu trnh c/ngh
Chng 13. Ti u ha qu trnh ct gt
Chng 14. Phng php thit k QTCN
Chng 15. QTCN ch to cc chi tit hp
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
Chng 16. QTCN ch to cc chi tit cng
Chng 17. QTCN ch to cc chi tit trc
Chng 18. QTCN ch to cc chi tit bc
Chng 19. QTCN ch to bnh rng
Chng 20. Nng sut lao ng
Chng 21. Cng ngh lp rp
Chng 22. m bo cht lng sn phm
Chng 23. Hng pht trin ca CN CTM
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
Ni dung mn hc
Chng 1. Nhng khi nim c bn
Chng 2. Cht lng b mt gia cng
Chng 3. chnh xc gia cng
Chng 4. Chun
Chng 5. Cc phng php gia cng ct gt
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
Phn m u
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
Chu trnh thit k & pht trin sn phm
Chng 1. Nhng khi nim c bn
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
I. Qu trnh SX v qu trnh CN
1. Qu trnh sn xut
2. Qu trnh cng ngh
3. Ch lm vic
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. Qu trnh sn xut
Qu trnh SX : QT con ngi tc ng vo ti nguyn, thin nhin to thnh sn phm
Theo ngha rng: QTSX bt u t khu khai qung, luyn kim, ch to phi, gia cng c, gia cng nhit, lp rp, sn, chy th, ng gi
Theo ngha hp: trong mt nh my SX c kh th QTSX khng bao gm khai qung v luyn kim, hoc trong nh my c kh ch chuyn ch to phi, ring lp rp hoc ng gi
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
2. Qa trnh cng ngh
L mt phn ca QTSX trc tip lm thay i trng thi v tnh cht ca i tng SX (thay i kch thc, hnh dng hnh hc v v tr tng quan). V d:
QTCN gia cng c
QTCN nhit luyn
QTCN lp rp
QTCN ch to phi (c, hn, dp, cn)
Xc nh QTCN hp l ri ghi thnh vn kin CN th vn kin c gi l qui trnh CN
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
3. Ch lm vic
L mt phn ca phn xng SX c dng thc hin cng vic bng mt hoc mt s cng nhn.
Ti ch lm vic c b tr cc loi dng c, g, my ct, thit b nng h, gi phi, chi tit hoc n v lp rp
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
II. Thnh phn SX ca nh my CTM (1)
Cc phn xng chun b phi (phn xng c, phn xng rn dp, phn xng hn)
Phn xng gia cng (g/c c, nhit luyn, dp ngui, g/c g, m, lp rp, sn)
Cc phn xng ph (p/x dng c, sa cha in, ch to khun mu, p/x th nghim, ch th)
Cc kho cha (vt liu, dng c, khun mu, nhin liu, sn phm)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
II. Thnh phn SX ca nh my CTM (2)
Cc trm cung cp nng lng (in, nhit, kh nn, trm cung cp nc)
Cc c cu vn chuyn (xe nng h, cn cu, ng ray vn chuyn trong ni b nh my)
Cc thit b v sinh-k thut (t/b si m, thng gi, ng ng cp nc, h thng cng rnh)
Cc b phn chung ca nh my (phng CN, phng TK, o lng, cc vn phng, nh n, trm x, h thng thng tin lin lc)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
III. Thnh phn ca qui trnh cng ngh
1. Nguyn cng
2. G
3. V tr
4. Bc
5. ng chuyn dao
6. ng tc
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. Nguyn cng
L mt phn QTCN c hon thnh lin tc ti mt ch lm vic do mt hay nhm cng nhn thc hin g/c mt hoc mt s chi tit cng lc. Nu khng c cng nhn phc v th gi l n/c TH. V d, kp A g/c B & C, sau quay u kp C g/c A th ta c 1 n/c. Nhng nu kp A g/c c lot chi tit ri quay u g/c c lot thi ta c 2 n/c. Hoc kp A g/c B,C trn mt my ri chuyn sang my khc g/c A th ta c 2 n/c. Tin ng knh ngoi v phay rnh then l 2 n/c
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
2. G
L mt phn ca QTCN c hon thnh trong mt ln g t mt hoc nhiu chi tit cng lc. V d, tin u B,C ri quay u tin u A l 2 ln g t
Mt n/c c th c mt hoc nhiu ln g t
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
3. V tr (1)
V tr l mt phn ca n/c c xc nh bi mt v tr tng quan gia chi tit v my hoc gia chi tit v g. V d, tin B,C ri quay u tin A l 2 v tr khc nhau
Mt n/c c th c mt hoc nhiu v tr
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
3. V tr (2)
Chi tit c g trn g quay c 4 v tr khc nhau
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
4. Bc
L mt phn ca n/c g/c mt b mt (hoc nhiu b mt) bng mt dao hoc nhiu dao vi ch ct khng thay i. Nu thay i b mt g/c hoc ch ct ta s chuyn sang bc khc. V d, tin 3 on A,B,C l 3 bc (khi dng mt dao), tin 4 mt u D,E,F,G l 4 bc. Sau khi tin, thay ch ct ta s c bc khc
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
5. ng chuyn dao
L mt phn ca bc ht i mt lng kim loi c cng ch ct v bng cng mt dao
V d: tin cc on A,B,C ta phi dng mt dao vi cng ch ct ct nhiu ln, mi ln ct l mt ng chuyn dao
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
6. ng tc
ng tc l hnh ng ca ngi cng nhn K my khi g/c hoc khi lp rp
V d: bm nt, quay dao, y ng, thay i ch ctCn i vi lp tp th ly chi tit, lau sch chi tit, bi m ln chi tit, cm cl, sit ai c
Vic phn chia thnh ng tc rt cn thit nh mc thi gian g/c v lp rp, ng thi nghin cu nng sut lao ng v t ng ha nguyn cng
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
IV. Sn lng & sn lng hng nm
Sn lng l s lng my, chi tit hoc phi c ch to ra trong mt n v thi gian
Sn lng hng nm ca chi tit c xc nh theo cng thc:
N = N1.m (1 + /100)
y: N s chi tit c SX trong mt nm
N1 s sn phm (s my) trong mt nm
m - s chi tit trong mt sn phm (mt my)
s chi tit c ch to d phng (5%)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
V. Cc dng sn xut
1. Sn xut n chic
2. Sn xut hng lot
3. Sn xut hng khi
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. Sn xut n chic (1)
L SX c s lng SP hng nm rt t (mt n vi chc chic), SP khng n nh do chng loi nhiu, chu k ch to li khng xc nh c. c im:
Ti mt ch lm vic g/c nhiu loi chi tit khc nhau
G/c v lp rp thc hin theo tin trnh CN
S dng TB v DC vn nng. My c b tr theo tng loi
S dng g, dng c o vn nng
Khng thc hin c vic lp ln hon ton
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. Sn xut n chic (2)
Cng nhn c trnh tay ngh cao
Nng sut lao ng thp, gi thnh sn phm cao
V d: dng SX n chic l ch to cc my hng nng, cc SP ch th hoc ch to theo n t hng
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
2. Sn xut hng lot (1)
L dng SX c SP hng nm khng qu t, SP c ch to theo tng lot vi chu k xc nh. c im:
Ti cc ch lm vic c thc hin mt s n/c c chu k lp li n nh
S dng cc my vn nng v c/d
Cc my c b tr theo dy chuyn CN
S dng nhiu d/c v /g chuyn dng
m bo nguyn tc lp ln hon ton
Cng nhn c trnh trung bnh
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
2. Sn xut hng lot (2)
Ty theo sn lng v mc n nh ca SP, ngi ta chia SX HL ra:
SX HL nh (gn vi SX C)
SX HL va
SX HL ln (gn vi SX hng khi)
V d SX HL: ch to my cng c, my nng nghip
Trong SX HL va c th t chc theo dy chuyn SX linh hot (sau mt thi gian c th g/c lot chi tit mi)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
3. Sn xut hng khi (1)
L dng SX c sn lng rt ln, SP n nh lu di (1-5 nm). c im:
Ti mt ch lm vic thc hin mt n/c no
Cc my c b tr theo dy chuyn cht ch
S dng nhiu my t hp, my t ng, my chuyn dng, ng dy t ng
G/c v lp rp c thc hin theo dy chuyn
S dng /g, dng c o chuyn dng
m bo nguyn tc lp ln hon ton
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
3. Sn xut hng khi (2)
Nng sut lao ng cao, gi thnh SP h
Cng nhn c trnh tay ngh khng cao nhng th iu chnh my li c trnh tay ngh cao
V d SX h/khi: ch to t, my ko, vng bi, bnh rng, c vt, cc thit b o lng
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
VI. Nhp sn xut (1)
Trong SX HL ln v HK thng s sng PP SX dy chuyn (c g/c c v lp rp). Theo PP ny th cc my c b tr theo th t cc n/c. S my (s v tr) v nng sut ca my phi tnh ton sao cho ng b (khng b nh n gia cc n/c)
Mun dy chuyn SX ng b phi tun theo nhp SX
Nhp SX l thi gian lp li chu k gia cng
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
VI. Nhp sn xut (2)
Cng thc tnh nhp sn xut t: t = F/q
F-thi gan lm vic theo ca, thng, nm (ph)
q s lng SP hoc chi tit c ch to ra trong thi gian F
V d, mt ca lm vic: 8x60 ph= 480 pht, g/c c 60 chi tit, vy nhp t s l:
t = 480/60 =8 pht hoc l bi s ca 8
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
VII. Xc nh dng sn xut
Khi c sn lng hng nm N, ta xc inh khi lng ca chi tit Q: Q = V. y: V l th tch ca chi tit (dm3 ), l khi lng ring (thp l 7,852kg/dm3, gang l 7,2 kg/dm3, nhm l 2,7 kg/dm3 v ng l 8,72 kg/dm3. Khi c N & Q ta dng bng sau xc nh dng sn xut
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
VIII. Tp trung v phn tn nguyn cng
1. Phng php tp trung nguyn cng
2. Phng php phn tn nguyn cng
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. P/php tp trung nguyn cng (1)
Tp trung nguyn cng l b tr nhiu bc CN vo mt n/c v thc hin trn mt my
Thng TT nguyn cng c thc hin i vi cc bc CN gn ging nhau nh khoan, khot, doa, ct ren hoc tin ngoi, tin trong
PP tp trung nguyn cng ng dng cho cc chi tit phc tp c nhiu b mt g/c
p dng PP ny phi dng nhiu my t hp, my nhiu trc chnh (g/c c tin hnh tun t trn tng trc chnh v ng thi trn nhiu v tr khc nhau)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. PP tp trung nguyn cng (2)
Trong trng hp ny thi gian g/c chi tit bng thi gian g/c trn mt trc chnh
Nng sut g/c tng nh g/c song song v s trng hp ca thi gian my
T/gian ph bng T/gian quay bn my i mt v tr
PP cn dng cc my nhiu dao g/c chi tit
PP tp trung nguyn cng cho php nng cao h s s dng mt bng sn xut
Nhc im ca PP: iu chnh my phc tp
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
2. PP phn tn nguyn cng
PP phn tn n/c: chia QTCN ra nhiu n/c nh, mi n/c c thc hin trn mt my
S dng cc my thng thng, cc dng c tiu chun v trang b CN n gin
PP c tnh linh hot cao (chuyn i i tng gia cng rt nhanh chng)
Hin nay, trong CTM thng p dng PP TT n/c trn c s TH SX
PP PT n/c ch p dng qui m SX ln nu trnh SX km nhn t gc k thut SX
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
Chng 2. Cht lng b mt gia cng
I. Khi nim
Cht lng b mt g/c c nh gi bng 2 yu t c trng:
Tnh cht c l ca lp kim loi b mt (mc bin cng, chiu su bin cng v ng sut d)
nhm b mt
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
II. Cc dng b mt gia cng
1- sng v nhm
2- sng v nhm va phi
3,4- b mt phng v nhm thp
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
III. nhm dc v nhm ngang
a) nhm dc
b) nhm ngang
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
IV. Cc yu t nh hng CL b mt
Tnh cht ca vt liu gia cng
PP gia cng (tin, bo, phay, mi)
Ch ct (S,V,t)
cng vng ca h thng cng ngh
Thng s hnh hc ca dao
Dung dch trn ngui
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
V. nhm b mt (1)
nhm b mt ( nhp nh t vi) l tp hp tt c nhng b li, lm vi bc cc nh
nh gi nhm ta v ng trung bnh. ng trung bnh c v sao cho tng din tch (phn gch ng) t hai pha bng nhau
Chiu di chun l l chiu di dng nh gi cc thng s ca nhm
Ra sai lch bnh phng trung bnh cng ca cc gi tr chiu cao h tnh t ng trung bnh trong phm vi chiu di chun l
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
V. nhm b mt (2)
Ra c xc nh:
l- chiu di chun, h- tung profin o c t ng trung bnh
Rz c xc nh theo cng thc:
[(H1+H3+H5+H7+H9) - (H2+H4+H6+H8+H10)]/5
Sm- bc nhp nh theo ng trung bnh (gi tr trung bnh cng ca cc bc nhp nh)
S bc nhp nh theo nh (gi tr trung bnh cng ca cc bc nhp nh theo nh)
n
l i
1a
0
h1
R hdll n
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
V. nhm b mt (3)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
VI. ng cong ca phn vt liu
Chiu di ca phn vt liu v tr no l tng chiu di ca phn kim loi i qua cc im ca nhm
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
VII. Cp nhm (1)
Tiu chun nh nc qui nh: nhm chia ra 14 cp. Cp 1 c nhm cao nht, cp 14 c nhm thp nht
Tr s Ra c cho khi yu cu nhm b mt t cp 6 n cp 12
Tr s RZ c ghi trn bn v nu yu cu nhm trong phm vi t cp 1 n cp 5 hoc cp 13 v 14 (RZ = 0,08~0,05 m)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
VII.Cp nhm (2)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
VIII. /hng ca /nhm n TCSD ca c/tit
nhm c nh hng n:
1. mn U ca chi tit
2. Qu trnh n mn ha hc trn b mt
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. /hng ca Ra n /mn U ca chi tit (1)
Ma st v mn ca chi tit my ph thuc v chiu cao v hnh dng ca nhm b mt v phng ca vt g/c
Cc im 01 v 02 ng vi mn ban u nh nht ca cc b mt tip xc
Ta thy: trong iu kin lm vic nng ng cong 2 dch chuyn v pha trn v bn phi ng vi nhm ti u (02)
ng cong 1: iu kin lm vic nh
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. /hng ca Ra n /mn U ca chi tit (2)
mn ban u c th san phng 70% chiu cao nhm
nhm c chn trn c s dung sai :
Khi ng knh lp ghp >50mm:
RZ = (0,1~0,15)
Khi ng knh lp ghp trong khong 18~50mm: RZ = (0,15~0,2)
Khi ng knh lp ghp
2. Qu trnh n mn ha hc trn b/mt
nhm nh hng ln n tnh chng n mn ha hc ca b mt chi tit
Cc ch lm cha cc tp cht nh axit, muiCc tp cht n mn b mt theo sn dc ca nhp nh v to thnh nhp nh mi. Nh vy, b mt c nhm cng cao th qu trnh n mn cng nhanh
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
X. /hng ca bin cng n TCSD
B mt bin cng tng bn mi ca chi tit ln khong 20%, tng chng mn ln 2~3 ln (hn ch kh nng gy ra cc vt nt ph hng chi tit)
B mt qu cng lm gim bn mi ca chi tit
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XI. /hng ca ng sut d n TCSD
ng sut d nn trn b mt tng bn mi ca chi tit, cn ng sut ko gim bn mi ca chi tit
V d: b mt chi tit thp c ng sut d nn tng bn mi ln 50% v c ng sut d ko s gim bn mi 30%
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XII. Cc y/t /hng n /nhm b/mt
1. Thng s hnh hc ca dao
2. nh hng ca tc ct
3. nh hng ca lng chy dao
4. nh hng ca chiu su ct
5. nh hng ca vt liu gia cng
6. nh hng ca rung ng
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
1. Thng s hnh hc ca dao
a) v b): S1>S2 ta c RZ trn hnh
b nh hn RZ trn hnh a
c) v d): hnh dng nhm thay i theo bn knh mi dao
e) bn knh mi dao r2 tng s lm gim nhm b mt
g) cc gc chnh v gc ph 1 c nh hng n nhm
Thng s hnh hc ca dao nh hng n nhm
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
2. nh hng ca tc ct
Khi V nh, bin dng t, nhit ct khng cao, do RZ thp. Nu V tng gn 20m/ph th nhit ct tng ln hng nghn nn sinh ra lo dao, lo dao lm thay i hnh dng mi dao lm tng RZ . Nu tng V ln na (100 m/ph), lo dao bin mt v RZ gim
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
3. nh hng ca lng chy dao
Nhn chung, khi tng lng chy dao S th nhm tng v bin dng do, bin dng n hi v rung ng. Nu S>0,15 th nhm tng nhanh (do bin dng n hi)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
4. nh hng ca chiu su ct
Chiu su ct nhn chung khng c nh hng ng k n nhm b mt g/c
Tuy nhin, nu chiu su ct qu ln th rung ng ca qu trnh ct ln s lm tng nhm
Nu chiu su ct qu nh s gy ra hin tng trt dao trn b mt g/c nn nhm tng. Hin tng trt dao xy ra khi t < 0,02~0,03 mm)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
5. nh hng ca vt liu gia cng
Vt liu do v dai (thp t cacbon) d bin dng, do nhm tng
Vt liu cng v gin (t bin dng), do nhm gim
Gim tnh do ca b mt gia cng bng bin cng cng lm gim nhm
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
6. nh hng ca rung ng
Rung ng lm thay i iu kin ma st, gy nn sng v nhm trn b mt gia cng
Rung ng sinh ra do nhiu nguyn nhn:
Tnh trng ca my
cng vng ca dao, chi tit v g
Gia cng vi ch ct khng hp l
Gia cng khng c dung dch trn ngui
Vt liu gia cng c tnh do cao
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XIII. P/php t bng b mt (1)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XIII. P/php t bng b mt (2)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XIV. P/php t cng b mt (1)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XIV. P/php t cng b mt (2)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XV. P/php t ng sut d b mt
Tng tc ct V hoc lng chy dao S cng c th tng hoc gim ng sut d
Lng chy dao S tng lm tng chiu su c ng sut d
Gc trc c tr s m gy ra ng sut d nn
Gia cng vt liu gin bng dng c ct c li to ra ng sut d nn, cn gia cng vt liu do thng gy ra ng sut d ko
Gia cng bng mi thng gy ra ng sut d ko, cn gia cng bng ai mi thng to ra ng sut d nn
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XVI. P/php nh gi nhm b mt
Phng php quang hc (dng knh hin vi)
Phng php o nhm bng my o profile
Phng php so snh bng mt (trong cc phn xng SX ngi ta mang vt mu so snh vi b mt gia cng v kt lun xem thuc cp bng no)
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XVII. P/php nh gi bin cng
Dng my o cng (tc dng ln b mt mt lc P, sau xc nh din tch S ca b mt do du kim cng n xung)
Cng thc tnh bin cng H:
H = P/S
H bin cng (N/mm2), P- lc tc dng ca u kim cng (N), S- din tch do u kim cng n xung (mm2)
chiu su bin cng dng u kim cng tc ng ln lt xung b mt mu t ngoi vo trong, sau mi ln tc ng ta o din tch b ln S n khi S khng thay i th dng li v o c chiu su b/c
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN
XVIII. P/php nh gi ng sut d
Phng php tia Rnghen (dng tia Rnghen kch thch ln b mt mu mt lp dy
5~10 m v sau mi ln kch thch ta chp nh th Rnghen. Phng php ny cho php o c c chiu su bin cng. Tuy nhin, phng php phc tp v tn thi gian cho iu chnh th Rnghen (10 gi cho mt ln o)
Phng php tnh ton lng bin dng (sau khi ht tng lp mng kim loi bng PP ha hc v in c kh ta tnh lng bin dng ca chi tit mu. Da vo lng bin dng ta xc nh c ng sut d
TS. Trng c Phc
B mn Cng ngh Ch to my Vin C kh BKHN