TCVN

TIU CHUN QUC GIA

TCVN 7937-1:2013

ISO 15630-1:2010THP LM CT B TNG V B TNG D NG LC - PHNG PHP TH - PHN 1: THANH, DNH V DY DNG LM CTSteel for the reintorcement and prestressing of concrete - Test methods - Part 1: Reintorcing bars, wire rod and wire

Li ni u

TCVN 7937-1:2013 thay th TCVN 7937-1:2009 (ISO 15630-1:2002)

TCVN 7937-1:2013 hon ton tng ng vi ISO 15630-1:2010 TCVN 7937-1:2013 do Ban k thut tiu chun quc gia TCVN/TC 17 Thp bin son, Tng cc Tiu chun o lng cht lng ngh, B Khoa hc v Cng ngh cng b.

TCVN 7937 (ISO 15630), Thp lm ct b tng v b tng d ng lc - Phng php th bao gm cc phn sau:

- Phn 1: Thanh, dnh v dy dng lm ct;

- Phn 2: Li hn;

- Phn 3: Thp d ng lc.

THP LM CT B TNG V B TNG D NG LC - PHNG PHP TH - PHN 1: THANH, DNH V DY DNG LM CT

Steel for the reintorcement and prestressing of concrete - Test methods - Part 1: Reintorcing bars, wire rod and wire

1. Phm vi p dng

Tiu chun ny quy nh cc phng php th dng cho thanh, dnh v dy dng lm ct b tng.

2. Ti liu vin dn

Cc ti liu vin dn sau rt cn thit cho vic p dng tiu chun ny. i vi cc ti liu vin dn c ghi nm cng b th p dng phin bn c nu. i vi cc ti liu vin dn khng ghi nm cng b th p dng phin bn mi nht, bao gm c cc b sung, sa i (nu c).

TCVN 197 (ISO 6892), Vt liu kim loi - Th ko.

ISO 7500-1, Metallic materials - Verification of static uniaxial testing machines - Part 1: Tension/compression testing machines - Verification and calibration of the force-measuring system (Vt liu kim loi - Kim nh cc my th ng trc tnh - Phn 1: My th ko/nn - Kim nh v hiu chun h thng o lc).ISO 9513, Metallic materials - Calibration of extensometers used in uniaxial testing (Vt liu kim loi - Hiu chun cc gin k c s dng trong php th n trc).

3. K hiu

K hiu s dng trong tiu chun ny theo Bng 1.

Bng 1 - K hiu

K hiun v ngha

a'mmChiu cao gn dc10.3.2; 11.3

ammmChiu cao gn ti im gia hoc chiu su rnh lm ti tm10.3.1.2; 11.3.2; 11.4.2

amaxammChiu cao gn ngang ln nht hoc chiu su rnh lm ln nht10.3.1.1

as,immChiu cao trung bnh ca phn th i khi chia mt gn thnh p phn trn chiu di (l hoc chiu su trung bnh ca phn th i khi chia mt rnh lm thnh p phn trn chiu rng ( b11.3.1

11.4.1

a1/4mmChiu cao gn ti v tr mt phn t hoc chiu su rnh lm ti v tr mt phn t10.3.1.2; 11.3.2; 11.4.2

a3/4mmChiu cao gn ti v tr ba phn t hoc chiu su rnh lm ti v tr ba phn t10.3.1.2; 11.3.2; 11.4.2

A% gin di sau khi t5.1; 5.3

Ag% gin di khng t l ti lc ln nht Fm5.3

Agt% gin di tng ti lc ln nht Fmiu 5

bmmChiu rng gn ngang ti im gia hoc chiu rng rnh lm10.3.8

cmmBc gn ngang hoc bc rnh lm10.3.3; 11.3

dmmng knh danh ngha ca thanh, dy hoc dnh5.3; 8.2; 8.4.7; 11.3

Dmmng knh gi un trong thit b th un hoc un li6.3; 7.3.2

emmKhe h trung bnh gia hai hng gn hoc hai hng rnh lm k nhau10.3.5

fHzTn s gia ti trong th mi dc trc8.1; 8.4.3

fp-Din tch tng i ca rnh lmiu 11

fR-Din tch tng i ca gniu 11

FmNLc ko ln nht trong th ko5.3

FPmm2Din tch mt ct dc ca mt rnh lm11.4.1

FrNPhm vi lc trong th mi dc trc8.1; 8.3; 8.4.2; 8.4.3

FRmm2Din tch mt ct dc ca mt gn11.3.1

FupNLc cn trn trong th mi dc trc8.1; 8.3; 8.4.2; 8.4.3

lmmChiu di gn ngang ti b mt phn cch rut gnHnh 6

n, m, q, p-i lng dng trong cc cng thc tnh fR, fP, FR v FP11.3; 11.4

PmmBc xon ca thanh xon ngui10.3.4; 11.3

r1mmKhong cch gia u kp v cc vch gii hn chiu di tnh ton khi o Agt bng phng php th cng5.3

r2mmKhong cch gia v tr t v cc vch gii hn chiu di tnh ton khi o Agt bng phng php th cng5.3

ReHMPaGii hn chy trn5.3

RmMPaGii hn bn5.3

Rp0,2MPaGii hn chy quy c ti gin di khng t l 0,2 %5.2; 5.3

Snmm2Din tch mt ct ngang danh ngha ca thanh, dnh v dy8.4.2

(Gc nghing ca gn ngang10.3.7

(Gc gia trc gn ngang hoc rnh lm vi trc ca thanh, dy hoc dnh10.3.6; 11.3

(Gc un trong th un hoc un li6.3; 7.3.1 (Hnh 4), 7.3 2

(lmmPhn tng thm ca chiu di gn ngang ti mt rut gnHnh 6

(Gc un li trong th un li7.3.1 (Hnh 4), 7.3.4

(-H s kinh nghim trong cng thc kinh nghim ca fR v fP11.3.2; 11.4.2

2(aMPaPhm vi thay i ng sut trong th mi ti dc trc8.4.2

(maxMPang sut ln nht trong th mi ti dc trc8.4.2

(eimmPhn chu vi khng cha gn hoc rnh lm10.3.5; 11.3.2; 11.4.2

CH THCH: 1 MPa = 1 N/mm2

a Trong mt s tiu chun sn phm, thng s ny c th c k hiu l h

4. Quy nh chung v mu thNu khng c tha thun hoc quy nh khc trong tiu chun sn phm, mu th phi c ly t thanh, dy hoc dnh trong iu kin nguyn trng.

Nu phi ly mu th t cun, mu th phi c nn thng trc khi tin hnh th bng phng php un n gin vi lng bin dng do t nht c th.

CH THCH: Vic nn thng mu th l quan trng i vi th ko v th mi.

Phng php un thng mu th (bng tay, bng my) phi c ch ra trong bo co th.

Khi phi xc nh cc ch tiu c tnh trong th ko hoc th mi, mu th c php lm ha gi nhn to (sau khi nn thng, nu c th), ph thuc vo yu cu ca tiu chun sn phm tng ng.

Nu tiu chun sn phm khng quy nh vic x l ha gi, khi c th p dng cc bc x l nh sau: nung nng mu th n 100 C, duy tr ti nhit ny trong vng 1 h min vi phm vi dao ng nhit l 10 C sau ly mu ra ri lm ngui t nhin trong khng kh tnh ti nhit mi trng.

Khi x l ha gi mu th, cc thng s iu kin ca qu trnh x l phi c a vo bo co th.

5. Th ko

5.1. Mu thMu th phi tun theo cc quy nh chung trong iu 4, chiu di t do ca mu th phi cho qu trnh xc nh gin di theo 5.3.

Nu xc nh gin di sau khi t (A) bng phng php th cng, mu th phi c vch du theo quy nh trong TCVN 197 (ISO 6892).

Nu cn xc nh gin di tng ti lc ln nht (Agt,) bng phng php th cng, phi vch trn mu th cc vch cch u nhau trn sut chiu di t do [xem TCVN 197 (ISO 6892)]. Khong cch gia cc vch ny phi l 20 mm, 10 mm hoc 5 mm ty theo ng knh ca thanh, dy hoc dnh.

5.2. Thit b thThit b th phi c kim tra v hiu chun theo ISO 7500-1 v c cp chnh xc ti thiu l cp 1.

Nu c s dng gin k th gin k phi t chnh xc cp 1 (xem ISO 9513) khi dng xc nh Rp0,2 v t chnh xc cp 2 (xem ISO 9513) khi dng xc nh (Agt).

Gin k dng xc nh gin di tng ti lc ln nht (Agt) phi c khong kp ti thiu l 100 mm. Khong kp ca gin k phi c a vo trong bo co th.

5.2. Tin hnh thTh ko phi c tin hnh theo TCVN 197 (ISO 6892). Khi phi xc nh Rp0,2, nu phn tuyn tnh ca biu lc - gin di khng ln hoc khng th hin r rng th phi s dng mt trong hai phng php sau:

- Tin hnh th khuyn co trong TCVN 197 (ISO 6892);

- Phn tuyn tnh ca biu lc- gin di phi c xem nh mt on thng ni cc im trn biu ti v tr 0,2 Fm v 0,5 Fm.

Trong trng hp c tranh chp th s dng phng php th hai.

Nu dc ca on thng ny sai lch ln hn 10 % so vi gi tr m un n hi l thuyt, php th s b coi l khng hp l.

Nu khng c quy nh c th trong tiu chun sn phm tng ng, phi s dng gi tr din tch mt ct ngang danh ngha tnh cc c tnh ko (ReH hoc Rp0,2, Rm).

Php th cng b coi l khng hp l nu mu th b t trong phn kp hoc ti v tr cch u kp nh hn 20 mm hoc d (ly gi tr ln hn).

Nu khng c quy nh c th trong tiu chun sn phm tng ng, khi xc nh gin di sau khi t A, chiu di c ban u phi l 5 ln ng knh danh ngha d. Trong trng hp c tranh chp, A phi c xc nh bng phng php th cng.

S dng quy trnh trong TCVN 197 (ISO 6892) xc nh gin di tng ti lc ln nht Agt vi mt s thay i v b sung nh sau:- Nu s dng phng php th cng o Agt, sau khi t, Agt phi c tnh theo cng thc sau:

Agt = Ag + Rm/ 2000

(1)

Trong Ag l gin di khng t l ti lc ln nht.

Ag phi c o trn mt chiu di c bng 100 mm ca hai phn gy t ca mu th, nm cch v tr t mt khong r2 c gi tr t nht l 50 mm hoc 2d (ly gi tr ln hn). Nu khong cch r1 gia u kp v chiu di c ny nh hn 20 mm hoc d (ly gi tr ln hn) th vic o s b coi l khng hp l. Xem Hnh 1.

Trong trng hp c tranh chp, s dng phng php o th cng.

CH DN:

a Chiu di kp. b Chiu di tnh ton 100 mm.

Hnh 1 - o Agt theo phng php th cng

6. Th un

6.1. Mu th

Mu th phi tun theo cc quy nh chung trong iu 4.

6.2. Thit b th

6.2.1. Phi s dng thit b th un theo nguyn l c m t trn Hnh 2.

CH THCH: Trn Hnh 2 biu din gi un v trc xoay cn trc dn th khng xoay. Tuy nhin cng c th b tr trc dn xoay cn gi un hoc trc khng xoay.

6.2.2. Th un cng c th c tin hnh trn thit b c mt gi un v nhiu trc [xem TCVN 198 (ISO 7438)].

CH DN:

1 Gi un.

2 Trc .

3 Trc dnHnh 2 - Nguyn l ca thit b th un

6.3. Tin hnh th

Th un c tin hnh trong khong nhit t 10 C n 35 C nu khng c tha thun khc.

i vi th un nhit thp, nu trong tha thun khng quy nh tt c cc iu kin th, p dng sai lch 2 C ca nhit tha thun. Mu th c ngm trong mi cht lm ngui thi gian m bo t c nhit quy nh trn ton b mu th (v d, t nht 10 min trong cht lng hoc t nht 30 min trong cht kh). Th un bt u trong 5 s sau khi ly ra khi mi cht. Thit b di chuyn c thit k v s dng sao cho nhit ca mu th c duy tr trong khong nhit quy nh.

Mu th phi c un quanh gi un.

Gc un (() v ng knh gi un (D) phi tun theo cc tiu chun sn phm tng ng.

6.4. nh gi kt qu th

Vic nh gi kt qu th un phi tun theo cc yu cu ca cc tiu chun sn phm tng ng.

Trong trng hp khng c cc yu cu c th, php th c coi nh t yu cu nu trn mu th khng xut hin cc vt nt c th nhn thy bng mt thng.

Vt nt do b mt c th xut hin trn gn hoc rnh lm v khng c coi l khng t. Vt nt c coi l vt nt b mt khi chiu su ca vt nt khng ln hn chiu rng ca vt nt.

7. Th un li

7.1. Mu th

Mu th phi tun theo cc quy nh chung trong iu 4.

7.2. Thit b th

7.2.1. Thit b un

S dng thit b un theo quy nh trong 6.2.

7.2.2. Thit b un li

C th s dng thit b un trn Hnh 2 un li. Tuy nhin nn s dng thit b un li nh trnh by trn Hnh 3.

Hnh 3 - V d v thit b th un li

7.3. Tin hnh th7.3.1. Quy nh chung

Tin hnh th un li bao gm 3 bc:

- Un mu;

- Ha gi nhn to;

- Un li.

Tin hnh th c biu din trn Hnh 4.

7.3.2. Un mu

Php th un c tin hnh trong khong nhit t 10 C n 35 C. Mu th phi c un quanh gi un.

Gc un (() v ng knh gi un (D) phi tun theo cc tiu chun sn phm tng ng.

Mu th phi c kim tra k pht hin cc vt nt nhn thy bng mt thng.

CH DN:

1 Gi un

2 Mu th

a V tr ban u

b V tr sau thao tc m t trong 7.3.2c V tr sau thao tc m t trong 7.3.4

Hnh 4 - S biu din tin hnh th un li

7.3.3. Ha gi nhn to

Nhit v thi gian ha gi nhn to phi tun theo cc tiu chun sn phm tng ng.

Nu tiu chun sn phm khng quy nh vic x l ha gi, khi c th p dng cc iu kin quy nh trong iu 4.

7.3.4. Un li

Sau khi lm ngui trong khng kh tnh xung n nhit trong khong t 10 C v 35 C, mu th phi c un ngc li n gc ( theo quy nh trong tiu chun sn phm tng ng.

7.4. nh gi kt qu th

Vic nh gi kt qu php th un li phi c tin hnh theo cc yu cu ca tiu chun sn phm tng ng.

Trng hp khng c quy nh v vic nh gi, mu th c coi nh t yu cu nu khng xut hin vt nt c th nhn thy c bng mt thng.

Vt nt do b mt c th xut hin trn gn hoc rnh lm v khng c coi l khng t. Vt nt c coi l vt nt b mt khi chiu su ca vt nt khng ln hn chiu rng ca vt nt.

8. Th mi dc trc

8.1. Nguyn l thPhp th mi dc trc l qu trnh tc dng ln mu th mt lc ko dc trc, lc ko ny c gi tr thay i theo chu k dng hnh sin vi tn s khng i f trong gii hn n hi (xem Hnh 5). Php th c tin hnh cho n khi mu th b ph hy hoc khi mu tuy cha b ph hy nhng s chu t ti mt gi tr chu k gia ti cho trc trong cc tiu chun sn phm tng ng.

CH DN:

F Lc. t Thi gian.

Hnh 5 - Biu chu k gia ti8.2. Mu th

Mu th phi tun theo cc quy nh chung trong iu 4. nn thng mu th, c th s dng my ch to sn phm.

B mt phn t do ca mu gia cc phn kp khng c php qua bt k mt qu trnh x l b mt di bt k hnh thc no. Chiu di phn t do ti thiu phi t 140 mm hoc 14d (ly gi tr no ln hn).8.3. Thit b thMy th mi phi c hiu chun theo ISO 7500-1. chnh xc phi t t nht 1 %. My th phi c kh nng duy tr gi tr lc cn trn, Fup, trong phm vi 2 % ca gi tr lc quy nh v gi c phm vi lc, Fr, trong phm vi 4 % gi tr quy nh.

8.4. Tin hnh th

8.4.1. Cc quy nh v mu th

Mu th phi c kp ln my th sao cho lc tc dng ln mu theo phng dc trc v khng c php xut hin momen un dc theo mu th.

8.4.2. Lc cn trn (Fup) v phm vi lc (Fr)

Lc cn trn (Fup) v phm vi lc (Fr) phi tun theo cc tiu chun sn phm tng ng.

CH THCH: Fup v Fr c th tnh ton t ng sut ln nht ((max) v phm vi ng sut (2(a) c cho trong cc tiu chun sn phm nh sau:

- Fup = (max x Sn- Fr = 2 (a x SnTrong Sn l din tch mt ct ngang danh ngha ca thanh, dy hoc dnh.

8.4.3. n nh lc v tn s gia ti

Php th phi c tin hnh trong iu kin n nh v lc cn trn (Fup), phm vi lc (Fr) v tn s gia ti (f). Trong sut ton b thi gian th khng c php c bt k mt gin on no v chu k gia ti. Tuy nhin, vn cho php tin hnh tip tc tr li mt php th b gin on t ngt. Mi gin on trong qu trnh th u phi a vo trong bo co th.

8.4.4. m chu k gia ti

S lng cc chu k gia ti phi c m ton b k t chu k gia ti y u tin.

8.4.5. Tn s gia ti

Tn s ca cc chu k gia ti phi c gi n nh trong sut php th v c gi nguyn trong mt lot php th. Tn s gia ti phi nm gia 1 Hz v 200 Hz.

8.4.6. Nhit th

Nhit ca mu th khng c vt qu 40 C trong sut thi gian th. Nu khng c quy nh khc th nhit ca phng th nghim phi c duy tr gia 10 C v 35 C.

8.4.7. Tnh hp l ca php th

Nu mu th b ph hy bn trong phn kp mu hoc trong phm vi 2d k t v tr kp hay ph hy pht sinh t mt ch d thng ca mu th th php th s b coi l khng hp l.9. Phn tch ha hc

Thnh phn ha hc phi c xc nh bng phng php phn tch quang ph.

Trong trng hp c tranh chp v phng php phn tch, thnh phn ha hc phi c xc nh bng mt phng php th trng ti c quy nh trong tiu chun quc gia hoc mt trong cc tiu chun quc t trong th mc ti liu tham kho.

10. o cc c trng hnh hc

10.1. Mu th

Mu th phi tun theo cc yu cu chung trong iu 4.

Chiu di ca mu th phi tin hnh cc php o theo 10.3.

10.2. Thit b o

Cc c trng hnh hc phi c o bng mt thit b c phn gii ti thiu nh sau:

- 0,01 mm khi o chiu cao ca gn ngang hoc ca gn dc v chiu su rnh lm i vi php o nh hn hoc bng 1 mm;

- 0,02 mm khi o chiu cao ca gn ngang hoc ca gn dc v chiu su rnh lm i vi php o ln hn 1 mm;

- 0,05 mm khi o khe gia hai hng gn ngang hoc rnh lm ca hai hng gn ngang hoc hng rnh lm lin k;

- 0,5 mm khi o bc gn ngang hoc rnh lm khi o bc gn hoc bc rnh lm (xem 10.3.3) hoc khi o khong cch gia hai im tng ng ca bc gn dc bc xon ca cc sn phm xon ngui (xem 10.3.4);

- 1 khi o gc nghing ca gn ngang hoc rnh lm v trc dc ca thanh, dnh hoc dy hoc khi o gc nghing ca sn gn.

Trong trng hp c tranh chp, phi s dng cc dng c o c trc tip thng dng nh calip, thc o chiu su.

10.3. Tin hnh o

10.3.1. o chiu cao gn ngang hoc chiu su rnh lm10.3.1.1. Gi tr ln nht amaxChiu cao gn ngang hoc chiu su rnh lm ln nht amax c xc nh bng cch ly gi tr trung bnh ca t nht ba s o chiu cao gn ngang hoc chiu su rnh lm ring l trn mt hng gn hoc rnh lm ti im cao nht hoc su nht ca tng gn ngang hoc rnh lm, khng tnh cc gn hoc rnh lm c k hiu ca thanh, dy hoc dnh.10.3.1.2. Gi tr ti mt v tr cho trc

Chiu cao gn ngang hoc chiu su rnh lm ti mt v tr cho trc (V d: ti im mt phn t, im gia hoc im ba phn t vi cc gi tr tng ng a1/4, am v a3/4) c xc nh bng cch ly gi tr trung bnh ca t nht ba s o chiu cao gn (hoc chiu su rnh lm) ring l trn mt hng gn (hoc rnh lm) ti v tr cn o ca tng gn (hoc rnh lm), khng tnh cc gn (hoc rnh lm) ghi k hiu ca thanh, dy hoc dnh.

10.3.2. Chiu cao gn dc (a')Chiu cao gn dc (a') l gi tr trung bnh ca t nht 3 s o chiu cao tng gn c ti ba v tr khc nhau.

10.3.3. Bc gn ngang hoc rnh lm (c)Bc gn ngang hoc rnh lm (c) c xc nh bng cch ly chiu di ca khong o chia cho s khe hoc g ca gn gia cc rnh lm c trong .

Khong o c th l khong cch t tim ca mt gn hoc rnh lm n tim ca mt gn hoc rnh lm khc trn cng mt hng, o trn ng thng song song vi trc dc ca sn phm. Khong o phi l:

- t nht 10 khe hoc g ca gn gia cc rnh lm;

- mt chiu di bc xon cho cc sn phm xon ngui.

10.3.4. Bc xon (P)Bc xon (P) ca thanh xon ngui l gi tr trung bnh ca cc s o khong cch gia hai im tng ng ca mt gn dc trn cng mt ng thng dc trc.

10.3.5. Phn chu vi khng cha gn hoc rnh lm ((ei)

Phn chu vi khng cha gn hoc rnh lm ((ei) c xc nh bng tng cc khe h trung bnh e gia cc cp gn hoc rnh lm ca hai hng gn hoc rnh lm k nhau tnh cho tng hng gn. Gi tr e c tnh da trn ti thiu ba gi tr o.

10.3.6. Gc nghing ca gn hoc rnh lm (()

Gc nghing ca gn hoc rnh lm (() c xc nh bng cch ly gi tr trung bnh cc gi tr gc nghing ring l o trn tng hng gn hoc rnh lm vi cng mt gc danh ngha.

10.3.7. Gc nghing sn gn ngang (()

Gc nghing sn gn ngang (() l gi tr trung bnh ca cc gc nghing ring l trn cng mt pha ca cc gn, c o nh biu din trn Hnh 6, o trn t nht l hai gn ngang khc nhau ca mt hng, khng tnh cc gn k hiu ca thanh, dy hoc dnh.

CH THCH: Mt ct A-A th hin mt chiu phng ca gn ngang.

Hnh 6 - Xc nh gc nghing sn gn (() v xc nh din tch mt ct dc ca mt gn (FR)

Gc nghing ca sn gn ngang (() c o bng cch xc nh ng thng ph hp nht gia hai im trn mt sn gn, xa th hin gc nghing, nhng trnh sn gn ti cc u mt ca y v nh ca gn nh v d trn Hnh 6.

10.3.8. Chiu rng ca gn ngang hoc chiu rng ca rnh lm (b)

Chiu rng ca gn ngang (b) l gi tr trung bnh ca ba s o trn tng hng, ti im gia ca gn, vung gc vi trc ca gn. Ch cc gn khng c s dng lm k hiu mi c xem xt o.

Chiu rng ca rnh lm (b) l gi tr trung bnh ca ba s o trn tng hng c ch to song song vi trc dc ca thanh, dy hoc dnh dc theo mt ng ngang qua rnh lm ti b mt ca thanh, dy hoc dnh.

11. Xc nh din tch gn hoc rnh lm tng i (fR hoc fP)

11.1. Gii thiu

Ti trng c truyn trong kt cu b tng thng qua lc bm dnh gia b tng v ct thp.

Lc bm dnh hiu qu nht chnh l lc bm dnh do lc ct sinh ra bi cc gn ngang hoc rnh lm trn b mt ca thp ct.

i vi thp ct c gn hoc c rnh lm, kh nng bm dnh c th c xc nh bng cc phng php sau:

- o cc c tnh hnh hc ca gn hoc vt rnh lm;

- o lc tng tc gia b tng v thp ct bng th nghim nh hoc th nghim un dm.

T cc s liu hnh hc s tnh c h s bm dnh, cn c gi l in tch gn tng i (fR) hoc din tch tng i ca rnh lm (fP).

11.2. Tin hnh o

Vic xc nh din tch tng i ca gn fR hoc din tch tng i ca rnh lm fP c tin hnh da trn cc kt qu o c trng hnh hc trong iu 10.

11.3. Tnh fR hoc fP11.3.1. Din tch tng i ca gn

Din tch tng i ca gn c tnh theo cng thc sau:

Trong cng thc trn:

- n l s hng gn ngang c trn chu vi;

- m l s lng mt nghing trn cc gn ngang khc nhau trong mt hng;

- q s gn dc ca thanh xon ngui;

- l din tch mt ct dc ca mt gn (xem Hnh 6), trong as,i l chiu cao trung bnh ca phn t th i trong mt gn ngang c chia thnh p phn c chiu di l (l.

S hng tng th hai ch p dng i vi thanh xon ngui v khng nn a vo nu gi tr ca n vt qu 30 % gi tr fR tng.

11.3.2. Cng thc gin lc

Nu cng thc tng qut trong 11.3.1 trn y kh p dng v phi dng cc thit b c bit, c th s dng cng thc gin lc.

C th s dng cc cng thc gin lc nh sau:

a) Cng thc hnh thang:

b) Cng thc Simpson:

c) Cng thc Parabol:

d) Cng thc kinh nghim:

Trong : ( l h s kinh nghim th hin tng quan gia fR hoc fP v am/c ng vi mt bin dng thanh, dy hoc dnh nht nh.

Cc gi tr a1/4, am, a3/4 c xc nh theo 10.3.1.2;

(ei c xc nh nh trong 10.3.5.

11.3.3. Cng thc dng tnh fRCng thc dng tnh fR phi ph hp vi tiu chun sn phm v phi c a vo trong bo co th.

11.4. Tnh fP11.4.1. Din tch tng i ca rnh lm

Din tch tng i ca rnh lm c tnh theo cng thc sau:

Trong n l s hng rnh lm.

l din tch mt ct dc ca mt rnh lm (xem Hnh 7) trong as,i l chiu su trung bnh ca v tr i ca rnh lm c chia thnh p phn chiu di (x.

Hnh 7 - Xc nh din tch mt ct dc ca mt rnh lm FP11.4.2. Cng thc gin lcNu cng thc tng qut trong 11.4.1 kh p dng v phi dng cc thit b c bit, c th s dng cng thc gin lc.

C th s dng cc cng thc gin lc nh sau:

a) Cng thc hnh thang:

b) Cng thc hnh ch nht:

c) Cng thc Parabol:

d) Cng thc kinh nghim:

Trong ( l h s kinh nghim th hin tng quan gia fR hoc fP v am/c ng vi mt bin dng thanh, dy hoc dnh nht nh;Cc gi tr a1/4, am, a3/4 c xc nh theo 10.3.1.2;

(ei c xc nh theo 10.3.5.

11.4.3. Cng thc dng tnh fPCng thc dng tnh fP phi ph hp vi tiu chun sn phm v phi c a vo trong bo co th.

12. Xc nh sai lch khi lng trn mt di danh ngha

12.1. Mu th

Vic xc nh sai lch khi lng trn mt di danh ngha phi c tin hnh trn cc mu c cc u c ct vung gc vi trc.

S thay i hnh dng ca gn/ rnh lm lin quan n vic ghi nhn thanh, dy, dnh lm ct c a vo tnh ton chiu di ca mu th.

12.2. chnh xc php o

Chiu di v khi lng ca mu th phi c o vi chnh xc ti thiu l 0,5 %.

12.3. Tin hnh o

Phn trm sai lch so vi khi lng trn mt di danh ngha phi c xc nh t sai lch gia khi lng trn mt di danh ngha thc t ca mu th so vi khi lng trn mt di danh ngha trong cc tiu chun sn phm tng ng.

13. Bo co thBo co th phi bao gm ti thiu cc thng tin sau:

a) S hiu ca tiu chun ny: TCVN 7937-1:2013 (ISO 15630-1:2010)

b) Tn ca mu th (bao gm c ng knh danh ngha ca thanh, dnh v dy);

c) Chiu di ca mu th;

d) Php th tin hnh v cc kt qu th tng ng;

e) Tiu chun sn phm tng ng, nu c;

f) Mi thng tin ph lin quan n mu th, thit b th v tin hnh th.

TH MC TI LIU THAM KHO[1] ISO 437:1982, Steel and cast iron - Determination of total carbon content - Combustion gravimetric method.[2] ISO 439:1994, Steel and iron - Determination of total Silicon content - Gravimetric method.

[3] ISO 629:1982, Steel and cast iron - Determination of total manganese content - Spectrophotometric method.

[4] ISO 671:1982, Steel and cast iron - Determination of total sulphur content - Combustion titrimetric method.[5] ISO 4829-1:1986, Steel and cast iron - Determination of total silicon content - Reduced molybdosilicate spectrophotometric method - Part 1: Silicon contents between 0,05 and 1,0%.

[6] ISO 4829-2:1988, Steel and cast iron - Determination of total silicon content - Reduced molybdosilicate spectrophotometric method - Part 2: Silicon contents between 0,01 and 0,05 %.

[7] ISO/TR 4830-4:1978, Steel - Determination of low carbon contents - Part 4: Coulometric method after combustion.[8] ISO 4934:2003, Steel and iron - Determination of sulphur content - Gravimetric method.

[9] ISO 4935:1989, Steel and iron - Determination of sulphur content - Infared absorption method after combustion in an induction furnace.[10] ISO 4937:1986, Steel and iron - Determination of chromium content - Potentiometric or visual titration method.[11] ISO 4938:1988, Steel and iron - Determination of nickel content - Gravimetric or titrimetric method.[12] TCVN 8498:2010 (ISO 4939:1984), Thp v gang - Xc nh hm lng niken - Phng php quang ph Dimethylblyoxime.[13] TCVN 8499 (ISO 4940:1985), Thp v gang - Xc nh hm lng niken - Phng php quang ph hp th nguyn t ngn la.

[14] TCVN 8503:2010 (ISO 4941:1994), Thp v gang - Xc nh hm lng molipen - Phng php quang ph Thiocyanate).

[15] TCVN 8504 (ISO 4942:1988), Thp v gang - Xc nh hm lng vanadi - Phng php quang ph N-BPHA).

[16] TCVN 8513:2010 (ISO 4943:1985), Thp v gang - Xc nh hm lng ng - Phng php quang ph hp th nguyn t ngn la).

[17] ISO 4945:1977, Steel - Determination of nitrogen content - Spectrophotometric method.

[18] TCVN 8514:2010 (ISO 4946:1984), Thp v gang - Xc nh hm lng ng - Phng php quang ph 2,2'-diquinolyl.

[19] ISO 4947:1986, Steel and cast iron - Determination of vanadium content - Potentiometric titration method.

[20] TCVN 198:2008 (ISO 7438:2005), Vt liu kim loi - Th un.

[21] ISO 9441:1988, Steel - Determination of niobium content - PAR spectrophotometric method.

[22] TCVN 8521:2010 (ISO 9556:1989), Thp v gang - Xc nh hm lng cacbon tng - Phng php hp th hng ngoi sau khi t trong l cm ng.

[23] TCVN 8509:2010 (ISO 9647:1989), Thp v gang - Xc nh hm lng vanadi - Phng php quang ph hp th nguyn t ngn la.[24] TCVN 8511:2010 (ISO 9658:1990), Thp v gang - Xc nh hm lng nhm - Phng php quang ph hp th nguyn t ngn la.

[25] TCVN 8512:2010 (ISO 10138:1991) Thp v gang - Xc nh hm lng crom - Phng php quang ph hp th nguyn t ngn la.

[26] ISO 10153:1997, Steel - Determination of boron content - Curcumin spectrophotometric method.

[27] ISO 10278:1995, Steel - Determination of manganese content - Inductively coupled plasma atomic emission spectrometric method.[28] TCVN 8506:2010 (ISO 10280:1991) Thp v gang - Xc nh hm lng ti tan - Phng php quang ph diantipyrylmetan.

[29] ISO 10697-1:1992, Steel - Determination of calcium content by flame atomic absorption spectrometry - Part 1: Determination of acid-soluble calcium content.

[30] ISO 10697-2:1992, Steel - Determination of calcium content by flame atomic absorption spectrometry - Part 2: Determination of total calcium content.

[31] ISO 10698:1994, Steel - Determination of antimony content - Electrothermal atomic absorption spectrometric method.

[32] TCVN 8505:2010 (ISO 10700:1994) Thp v gang - Xc nh hm lng man gan - Phng php quang ph hp th nguyn t ngn la.

[33] TCVN 8519:2010 (ISO 10701:1994) Thp v gang - Xc nh hm lng lu hunh - Phng php quang ph phc xanh metylen.

[34] ISO 10702:1993, Steel and iron - Determination of nitrogen content - Titrimetric method after distillation.

[35] TCVN 8517:2010 (ISO 10714:1992) Thp v gang - Xc nh hm lng pht pho - Phng php quang ph photphovanadomolipdat.

[36] ISO/TR 10719:1994, Steel and iron - Determination of non-combined carbon content - infrared absorption method after combuslion in an induction furnace.

[37] ISO 10720:1997, Steel and iron - Determination of nitrogen content - Thermal conductimetric method after fusion in a current of inert gas.

[38] TCVN 8502:2010 (ISO 11652:1997) Thp v gang - Xc nh hm lng coban - Phng php quang ph hp th nguyn t ngn la.

[39] ISO 11653:1997, Steel - Determination of high cobalt content - Potentiometric titration method after separation by ion exchange.

[40] ISO 13898-1:1997, Steel and iron - Determination of nickel, copper and cobalt contents - Inductively coupled plasma atomic emission spectrometric method - Part 1: General requirements and sample dissolution.

[41] ISO 13898-2:1997, Steel and iron - Determination of nickel, copper and cobalt contents - Inductively coupled plasma atomic emission spectrometric method - Part 2: Determination of nickel content.

[42] ISO 13898-3:1997, Steel and iron - Determination of nickel, copper and cobalt contents - Inductively coupled plasma atomic emission spectrometric method - Part 3: Determination of copper content.

[43] ISO 13898-4:1997, Steel and iron - Determination of nickel, copper and cobalt contents - Inductively coupled plasma atomic emission spectrometric method - Part 4: Determination of cobalt content.

[44] ISO/TS 13899-1:2004, Steel - Determination of Mo, Nb and W contents in alloyed steel - Inductively coupled plasma atomic emission spectrometric method - Part 1: Determination of Mo content.

[45] ISO 13899-2:2005, Steel - Determination of Mo, Nb and W contents in alloyed steel - Inductively coupled plasma atomic emission spectrometric method - Part 2: Determination of Nb content.

[46] ISO/TS 13899-3:2005, Steel - Determination of Mo, Nb and W contents in alloyed steel - Inductively coupled plasma atomic emission spectrometric method - Part 3: Determination of W content.

[47] TCVN 8501:2010 (ISO 13900:1997) Thp - Xc nh hm tng bo - Phng php quang ph curcumin sau chng ct.

[48] TCVN 8520:2010 (ISO 13902:1997) Thp v gang - Xc nh hm lng lu hunh cao. Phng php hp th hng ngoi sau khi t trong l cm ng.

[49] ISO/TR 15349-1:1998, Unalloyed steel - Determination of low carbon content - Part 1: Infrared absorption method after combustion in an electric resistance turnace (by peak separation).[50] ISO 15349-2:1999, Unalloyed steel - Determination of low carbon content - Part 2: Intrared absorption method after combustion in an induction furnace (with preheating).

[51] ISO/TR 15349-3:1998, Unalloyed steel - Determination of low carbon content - Part 3: Infrared absorption method after combustion in an electric resistance furnace (with preheating).

[52] ISO 15350:2000, Steel and iron - Determination of total carbon and sulfur content - Infrared absorption method after combustion in an induction furnace (routine method).

[53] ISO 15351:1999, Steel and iron - Determination of nitrogen content - Thermal conductimetric method after fusion in a current of inert gas (Routine method).

[54] ISO 15353:2001, Steel and iron - Determination of tin content - Flame atomic absorption spectrometric method (extraction as Sn-SCN).

[55] ISO 15355:1999, Steel and iron - Determination of chromium content - Indirect titration method.

[56] ISO 16918-1:2009, Steel and iron - Determination of nine elements by the inductively coupled plasma mass spectrometric method - Part 1: Determination of tin, antimony, cerium, lead and bismuth.

[57] ISO 17053:2005, Steel and iron - Determination of oxygen - Infrared method after fusion under inert gas.

[58] ISO 17054:2010, Routine method for analysis of high alloy steel by X-ray fluorescence spectrometry (XRF) by using a near-by technique.

[59] ISO/TR 17055:2002, Steel - Determination of silicon content - Inductively coupled plasma atomic emission spectrometric method.

[60] TCVN 8510:2010 (ISO 17058:2004) Thp v gang - Xc nh hm lng asen - Phng php quang ph._1472364833.unknown

_1472365270.unknown

_1472361846.unknown