Thut ng v k hiu mi hn 1

PHN II

THUT NG V K HIU MI HN 1. MT S KHI NIM V CC HIP HI, TIU CHUN QUC GIA

1.1 HIP HI AWS : American Welding Society.

Hip hi hn Hoa K. a ra b tiu chun p dng cho hn kt cu thp.

ASME : American Society Mechanical Engineers. Hip hi k s c kh Hoa K. a ra b tiu chun p dng cho ch to ni hi, bnh, bn p lc.

ASTM : American Society for Testing and Meterials. Hip hi vt liu & kim tra vt liu Hoa K. a ra b tiu chun p dng cho vt liu v kim tra.

API : American Petrolium Institute. Vin du m Hoa K. a ra b tiu chun p dng cho ch to tc, bn cha xng du.

1.2 QUC GIA TCVN: Tiu chun Vit nam. KS : Korean Industrial Standard

Tiu chun cng nghip Hn Quc.

JIS : Japanese Industrial Standard Tiu chun cng nghip Nht Bn.

ANSI : American National Standard Institute. Vin tiu chun quc gia Hoa K.

DIN : Deutschs Institute for Normung Tiu chun quc gia c

1.3 QUC T

ISO : International Organization of Standardization T chc Quc t v Tiu chun ho

2. THUT NG V PHNG PHP HN

2.1 Hn h quang tay (Hn h quang que hn c v bc) Shielded Metal Arc Welding - SMAW

L phng php hn h quang to ra s lin kt ca cc kim loi bng cch s dng nhit lng ca h quang gia que hn c thuc bc v vt hn. S bo v kim loi vng hn l do kh phn hy khi thuc bc que hn chy.

Thut ng v k hiu mi hn 2

Phng php hn ny khng cn s dng lc p. Kim loi in y b

sung t que hn. 2.2 Hn h quang kim loi trong mi trng kh bo v.

Gas Metal Arc Welding - GMAW L phng php hn h quang to ra s lin kt ca cc kim loi bng

cch s dng nhit lng ca h quang gia kim loi in y nng chy lin tc (dy hn nng chy) v vt hn. Kh bo v c cung cp t ngun kh bn ngoi bo v h quang hn v kim loi vng hn.

Kh bo v l kh tr, kh hot tnh hoc hn hp kh. Mt vi dng bin i ca phng php ny c tn gi l hn MIG,

MAG v hn CO2.

2.3 Hn h quang dy hn c li thuc Flux Cored Arc Welding - FCAW

L phng php hn h quang to ra s lin kt ca cc kim loi bng cch s dng nhit lng ca h quang gia kim loi in y nng chy lin tc (dy hn nng chy) v vt hn. Vic bo v h quang v kim loi vng hn nh kh do thuc hn trong li dy hn chy to ra v kh c cung cp t ngun kh bn ngoi (nu c s dng).

Phong php ny c th khng dng n kh bo v.

2.4 Hn h quang in cc tungsten trong mi trng kh tr. Gas Tungsten Arc Welding - GTAW

L phng php hn h quang to ra s lin kt ca cc kim loi bng cch s dng nhit lng ca h quang gia in cc Vonfram (W) khng nng chy v vt hn. Vic bo v h quang v kim loi vng hn nh kh tr (Ar, He,...) c cung cp t ngun kh bn ngoi.

V vy, phng php ny thng c gi l hn TIG. Trong khi hn c th s dng hoc khng s dng dy, que hn ph. Trong

trng hp khng s dng dy, que hn ph, mi hn c hnh thnh do kim loi c bn nng chy to ra.

2.5 Hn h quang di lp thuc.

Submerged Arc Welding SAW L phng php hn h quang to ra s lin kt ca cc kim loi bng

cch s dng nhit lng ca h quang gia in cc kim loi trn v vt hn. H quang v kim loi nng chy c bo v bng kh bo v v lp x do thuc hn nng chy to ra.

Kim loi in y thu c b xung t in cc dy hn hoc t kim loi b sung dng ht.

Thut ng v k hiu mi hn 3

3. CC LOI LIN KT HN

Cc mi hn c th c ng dng

Lin kt gip mi (Butt joint)

- Rnh vung - Rnh ch V - Rnh vt xin - Rnh ch U - Hn in tr i u

- Rnh ch J - Rnh -V- loe - Rnh vt xin loe - Hn nng chay i u

Lin kt gc (Corner joint)

- Mi hn gc - Rnh vung - Rnh ch V - Rnh vt xin - Rnh ch J - Rnh -V- loe - Rnh ch U

- Rnh vt xin loe - Hn im - Hn in cc gi - Hn ng lin - Hn nng chy i u - Mi hn gc b g - Mi hn cnh b g

Lin kt chng (Lap joint)

- Hn gc - Hn nt - Hn khe hp - Rnh vt xin

- Rnh ch J - Rnh vt xin loe - Hn im - Hn in cc gi - Hn ng lin

Lin kt ch -T (Tee joint)

- Hn gc - Hn nt - Hn khe hp - Rnh vung - Hn in cc gi

- Rnh ch J - Rnh vt xin loe - Rnh vt xin - Hn im - Hn ng lin - Hn nng chy i u

Lin kt mp kn (Edge joint)

- Hn nt - Hn khe hp - Rnh vung - Rnh vt xin - Hn im - Rnh ch U

- Rnh ch J - Hn ng lin - Rnh ch V - Hn in cc gi - Mi hn cnh b g - Mi hn gc b g

CC YU T C BN CA MI GHP

Thut ng v k hiu mi hn 4

4. CC MINH HO MI HN

1. Mi hn rnh vung Square - Groove weld

2. Mi hn rnh -V- n Single-V-Groove

3. Mi hn rnh -V- kp Double-V-Groove

4. Mi hn rnh vt n

Single-Bevel-Groove 5. Mi hn rnh vt kp Double-Bevel-Groove

6. Mi hn rnh -U- n Single-U-Groove

7. Mi hn rnh -U-kp Double-U-Groove

8. Mi hn rnh -J- n Single-J-Groove

9. Mi hn rnh -J- kp Double-J-Groove

10. Mi hn gc mt bn Single-Fillet

11. Mi hn gc hai bn Double-Fillet

12. Rnh V loe

Flare-V 13. Mi hn b g

Flange-Edge 14. Git hn

Bead 15. Mi hn nt

Plug

16. Mi hn im hoc mi hn ng

Arc Spot or Arc Seam

Thut ng v k hiu mi hn 5

5. NH NGHA TNG PHN MI HN GIP MI & MI HN GC

1. GROOVE ANGLE (A):

Gc m mp hn. L ton b gc ca rnh gia cc phn c ghp mi to rnh hn

2. BEVEL ANGLE (A): Gc vt ca mp hn. L gc c to gia vic s l mp ca mt chi tit v mt phng vung gc vi b mt ca chi tit .

3. PLATE THICKNESS (T): Chiu dy vt liu Chiu dy ca vt liu c hn.

4. ROOT FACE (RF): dy mp hn (Mp cn). L mt rnh lin k ti chn ca mi ghp.

5. ROOT OPENING (RO): Khe h h. L s tch ra gia cc chi tit c ghp mi cnh chn ca mi ghp.

6. GROOVE FACE: B mt rnh. Bao gm b mt ca chi tit trong rnh.

7. SIZE OF WELD (S): Kch thc mi hn. ngu ca mi ni (chiu su ca gc xin cng vi ngu chn theo l thuyt). Kch thc ca mi hn rnh v rnh c hiu lc chnh l mt

1. LEG OF A FILLET WELD:

Cnh ca mi hn gc. L khong cch t gc ca mi lin kt ti chn ca mi hn gc.

2. ACTUAL THROAT OF A FILLET WELD:

Khong cch thc t ca mt mi hn gc. L khong cch ngn nht t gc ca mi hn gc ti b mt ca n.

3. FACE OF WELD:

B mt ca mi hn. L b mt phi ra ca mi hn trn mt phng t bt k mi hn no hon thin.

4. SIZE OF WELD (S):

Kch thc ca mi hn. di chn ca mi hn gc.

5. ROOT OF A WELD:

Gc ca mi hn. Bt k cc im mt sau ca mi hn phn cch vi b mt kim loi c bn.

6. DEPTH OF FUSION:

Chiu su ngu chy. L khong cch ngu chy m rng vo trong kim loi c bn hoc xuyn qua t b mt kim loi nu chy trong thi gian hn.

7. TOE OF A WELD:

Chn ca mi hn. L s ni lin gia b mt ca mi hn v kim loi c bn

MI HN GIP MI MI HN GC

456

2 37

1

3

5

1

6

2

4

7

Thut ng v k hiu mi hn 6

6. THUT NG CC KHUYT TT HN

Arc Strikes: Vt gy h quang.

S thiu thn trng mang tnh cht khng lin tc c kt qu t h quang, gm c mt vi vng kim loi b nng chy, kim loi vng nh hng nhit, hoc thay i trong b mt nghing ca mt vi i tng kim loi. Vt gy h quang c th l l do ca in cc hn h quang, cc c thc kim tra t tnh, hoc cp hn b c sn.

Blowhole: R hnh ng.

L mt thut ng khng tiu chun thay th cho Porosity.

Concavity: B mt lm. L khong cch ln nht t b mt ca mi hn gc lm vung gc vi ng ni cc chn mi hn.

Cracks: Nt.

Loi khe nt c tnh khng lin tc biu th c im bng u sc nhn v c t l rt ln gia chiu di v chiu rng khe h chim ch.

Crater: H.

Ch tht xung thnh h ti im kt thc ca mi hn.

Crater Cracks (star crack): Nt hnh sao. Vt nt trong h, thng im kt thc ca mi hn.

Incomplete Fusion: S nu chy khng hon ton.

Mt mi hn c tnh khng lin tc trong s nu chy khng xy ra gia kim loi mi hn v nu chy b mt hoc phn tip gip cc ng hn.

Lack of Fusion: Thiu chy L mt thut ng khng tiu chun th cho incomplete fusion.

Longitudinal Crack: Nt theo chiu dc Mt mi nt cng vi phn ln trc ca n c nh hng gn nh song song vi trc ca mi hn.

Overlap: Chng lp.

S nh ra ca kim loi mi hn vt xa hn chn ca mi hn hoc gc mi hn.

Porosity: Trng thi r, xp.

Thut ng v k hiu mi hn 7

L loi l hng c tnh khng lin tc c to nn bi kh cn nm li trong kim loi mi hn sau khi qu trnh ng c kt thc.

Root Crack: Nt gc mi hn.

Vt nt trong mi hn hoc vng nh nhit xy ra t gc ca mi hn.

Slag inclusion: Ngm x

L vt liu c phi kim loi nm li trong kim loi mi hn hoc gia kim loi mi hn v vt liu c bn.

Spatter: Bn to.

Cc ht nh kim loi b bn ra trong khi hn nng chy, cc ht khng hnh thnh t b phn ca mi hn.

Toe Crack: Nt chn.

Vt nt trong mi hn hoc trong vng nh hng nhit xy ra t chn ca mi hn.

Transverse Crack: Nt theo chiu ngang.

Mt mi nt cng vi phn ln trc ca n c nh hng gn nh vung gc vi trc ca mi hn.

Undercut: Chy cnh (chy chn).

Mt rnh b nu chy vo trong kim loi c bn gn st chn mi hn hoc gc mi hn v tri li khng c lp y bng kim loi mi hn.

Underbead Crack: Nt di ng hn

Mt vt nt trong vng nh hng nhit thng thng khng m rng ln b mt ca kim loi c bn.

Underfill: Lm b mt Ch lm trn b mt mi hn hoc b mt gc c m rng xung thp hn lin k b mt ca kim loi c bn.

Thut ng v k hiu mi hn

7. MINH HO CC KHUYT TT TRONG MI HN

Chy chn(Undercut)

Nt gc(Root crack)

R kh(Porosity'blowhole')

Chy chn(Undercut)

Ngm x(Slag inclusion)

Ming b hn(Crater)

Ngu chy khng hon ton(Incomplete fusion) Nt chn

(Toe Crack)

Chng lp (Overlap)

Nt di ng hn(Underbead Crack)

Nt di ng hn(Underbead Crack)

Nt dc mi hn(Longitudinal crack)

H (Pit)

Thut ng v k hiu mi hn

MINH HO CC KHUYT TT TRONG MI HN (TIP)

Ngu chy khng hon ton(Incomplete fusion)

Chng lp (Overlap)Chng lp(Overlap)

Ngm x (Slag inclusion)

Nt ngang mi hn(Transverse crack)

Lm b mt(Underfill)

Nt lu hunh(Sulphur crack)

Ngm x

Nt hnh sao(Crater crack)

Tch lp do lu hunh(Sulphur Segregation)

Lm b mt(Underfill)

Thut ng v k hiu mi hn 10

8. CC T TH HN

Trc ca mi hn nm ngang

Trc ca mi hn ng Trc ca mi hn

nm ngang

Thut ng v k hiu mi hn 11

Thut ng v k hiu mi hn 12

9. K HIU MI HN

K HIU MI HN C BN V NGHA V TR CA CHNG

Hn g

ngha v tr

Gc Hn nt hoc khe

hp

Hn im hoc in cc gi

Hn ng

Hn mt sau hoc tm m

Hn ph b mt

vt song song i vi mi

ghp hn ng thau

Hn mp

Pha bn

mi tn

Pha bn kia mi tn

Khng s dng

C hai pha

Khng s dng

Khng s dng

Khng s dng

Khng s dng

Khng s dng

Khng s dng

Khng s dng Khng s

dng

Khng s dng

Khng s dng

Khng s dng

Khng s dng

CC K HIU B XUNG

ng vin Mi hn tt c chu vi

Mi hn ngoi hin

trng

Xuyn thu

Tm m Bng Li Lm

K hiu mi hn rnh

K hiu mi hn rnh

Thut ng v k hiu mi hn 13

V TR CC YU T TIU CHUN CA K HIU MI HN

Bc (khong cch ttm n tm ca mi hn)

TS (E) L - P

(N)

F

AR

Kch thc bnkia ca mi

tn ch

Kch thc nimi tn ch

Gc m rnh hn;. gc tng ca lkhot loe ming i vi hn nt

Khe h;. chiu su ca mi hn clp y i vi hn nt v hn khe hp

K hiu b xung i viphng php hon thin

K hiu b xung chohnh dng b mt

Kch thc c hiu lc(theo tnh ton)

Chiu su ngu chy; Kch thcm bo cho mi hn chc chn

c im kthut; Phngphp hn, hoctham chiu khc.

ui (c b qua khis tham chiu khngc s dng)

K hiu mi hnc bn hoc nhngchi tit tham kho

Chiu di mi hn, trong mi hn gckhng lin tc, hoc trong hn im

K hiu mi hnngoi hin trng

K hiu mi hntt c xung quanh

Mi tn chmi hn

ngtham chiu

S mi hn im, hn ng, hninh tn, hn nt, hn khe hp, hoc

cc mi hn in cc gi

Cc yu t trong vng ny c ginguyn trong khi ui v mi tn

quay ngc li

C

h

a

i

b

n

Thut ng v k hiu mi hn 14

CC K HIU HN C BN V CC NGHA V TR KHC

Hn g Rnh

Gc Vung Ch V Vt xin Ch

U Ch

J Ch V

loe Vt xin

loe

ngha v tr

Pha bn mi tn

ch

Mt bn kia mi

ghp

Khng s dng

C hai bn

Khng s dng

Khng s dng

Khng s dng

Khng s dng

Khng s dng

Khng s dng

Khng s dng

Bn ny hoc bn

kia khng quan trng