TCVN 6016-2011 Xi măng - Xác định cường độ.pdf
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Transcript of TCVN 6016-2011 Xi măng - Xác định cường độ.pdf
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TCVN T I U C H U N Q U C G I A
TCVN 6016:2011 ISO 679:2009
Sot xt ln 2
XI MNG PHNG PHP TH XC NH CNG
Cement Test methods
Determination of strength
H NI 2011
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Mc lc
Trang
Li ni u ............................................................................................................................ ..4
Li gii thiu ...............................................................................................................................5
1 Phm vi p dng .................................................................................................................7
2 Ti liu vin dn................................................................................................................. 8
3 Nguyn tc..........................................................................................................................8
4 Thit b, dng c ................................................................................................................8
5 Thnh phn va..19
6 Chun b va ..........................................20
7 Chun b mu th......................................................................................................... .21
8 Bo dng mu th .........................................................................................................21
9 Cch tin hnh ............................................................................................................. .23
10 Kt qu th nghim...........................................................................................................24
11 Th nghim chng nhn ct tiu chun ISO v thit b ln cht thay th ...........................26
Ph lc A (Quy nh) Thit b v cc qui trnh ln cht kiu rung thay th c chng nhn tng ng vi thit b v qui trnh ln cht kiu dn .........................................................................34
Th mc ti liu tham kho........................................................................................................39
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Li ni u
TCVN 6016:2011 thay th TCVN 6016:1995.
TCVN 6016:2011 hon ton tng ng vi ISO 679:2009.
TCVN 6016:2011 do Vin Vt liu Xy dng B Xy dng bin son, B Xy dng ngh, Tng Cc Tiu chun o lng Cht lng thm nh, B Khoa hc v Cng ngh cng b.
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Li gii thiu
TCVN 6016:2011 do Vin Vt liu Xy dng - B Xy dng bin son trn c s chuyn dch t tiu chun ISO 679:2009. Tuy nhin, m bo iu kin th nghim ph hp vi iu kin Vit Nam: kh hu, mi trng, tiu chun yu cu k thut ca xi mng poc lng, TCVN 6016:2011 la chn iu kin nhit th nghim, xi mng poc lng dng th nghim chng nhn ct tiu chun ISO quy nh cc iu nh sau:
4.1 nhit phng th nghim ch to mu th c duy tr (27 2) 0C;
4.2 nhit phng dng h hoc t dng h bo dng cc mu th cn trong khun c duy tr (27 1) 0C;
4.3 nhit ca nc trong b ngm mu th c duy tr (27 1) 0C;
12.2.2.2 xi mng dng th chng nhn ct tiu chun ISO l xi mng poc lng PC40 hoc PC50.
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T I U C H U N Q U C G I A TCVN 6016:2011
Xi mng Phng php th Xc nh cng
Cement Test methods Determination of strength
1 Phm vi p dng
Tiu chun ny quy nh phng php xc nh cng nn v cng un (nu c yu cu) ca va cha mt phn xi mng, ba phn ct tiu chun ISO v mt na phn nc tnh theo khi lng. Phng php ny p dng cho cc loi xi mng thng thng, cc loi xi mng v vt liu khc m tiu chun ca n vin dn ti phng php ny. Phng php ny c th khng p dng cho cc loi xi mng khc m c tnh cht c bit, v d nh thi gian bt u ng kt rt ngn.
Tiu chun ny m t thit b v qui trnh chun, ngoi ra cn quy nh phng php th chng nhn ct tiu chun ISO, cc thit b v qui trnh thay th khc.
2 Ti liu vin dn
Cc ti liu vin dn sau y l cn thit p dng tiu chun ny. i vi cc ti liu vin dn 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 sa i, b sung (nu c). TCVN 5906:2007 (ISO 1101:2004), c tnh hnh hc ca sn phm (GPS) - Dung sai hnh hc - Dung sai hnh dng, hng, v tr v o.
TCVN 5707:2007 (ISO 1302:2002), c tnh hnh hc ca sn phm (GPS) - Cch ghi nhm b mt trong ti liu k thut ca sn phm.
ISO 3310 1, Test sieves Technical requiments and testing Part 1: Test sieves of metal wire cloth (Sng th nghim Yu cu k thut v phng php th - Phn 1: Sng th nghim c li sng bng kim loi). ISO 4200, Plain and end steel tubes, welded and seamless General tables of dimensions and masses per unit length (ng thp u trn c hn v khng c mi ni - Bng tng hp v kch thc v khi lng theo chiu di n v).
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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 tnh n nh ca my nn mt trc - Phn 1: My th ko/nn - S kim nh v hiu chun h thng o lc).
3 Nguyn tc
Phng php bao gm cch xc nh cng nn v cng un (nu c yu cu) ca cc mu th hnh lng tr c kch thc 40 mm x 40 mm x 160 mm.
Cc mu th ny c c t mt m va do cha mt phn xi mng, ba phn ct tiu chun ISO v mt na phn nc (t l nc/xi mng l 0,50) tnh theo khi lng. Ct tiu chun ISO t cc ngun v cc nc khc nhau c th c s dng vi iu kin kt qu cng xi mng khi s dng ct khng sai khc ng k so vi ct chun ISO (xem iu 11). Trong qui trnh chun, va c trn bng my v ln cht trong khun nh s dng thit b dn. Thit b ln cht v cc qui trnh thay th khc c th c s dng vi iu kin kt qu cng xi mng khng sai khc ng k so vi s dng thit b dn v qui trnh chun (xem iu 11 v Ph lc A). Trong trng hp c khiu ni hoc tranh chp, ch thit b v qui trnh chun c s dng.
Cc mu th c bo dng trong khun khng kh m 24 h, sau c tho khun ri ngm ngp trong nc cho n tui th cng .
n tui th yu cu, cc mu th c vt ra khi ni bo dng, b gy i bng lc un, xc nh cng un nu c yu cu, hoc b gy i bng cc bin php thch hp khc m khng gy ng sut c hi cho cc na lng tr v mi na mu gy dng th cng nn.
4 Thit b, dng c
4.1 Phng th nghim, ch to mu th c duy tr nhit (27 2) 0C v m tng i khng nh hn 50 %.
Nhit v m tng i ca khng kh trong phng th nghim c ghi li t nht mt ln mi ngy trong gi lm vic.
Cc phng th nghim th nghim ph hp vi tiu chun ny nn xem xt vic nng cao tin cy cho cc kt qu th nghim c to ra bng s ph hp vi cc yu cu ca TCVN ISO/IEC 17025.
4.2 Phng hoc t dng h, bo dng mu th cn trong khun c duy tr nhit (27 1) 0C v m tng i khng nh hn 90 %. Nhit v m tng i ca phng hoc t dng h c ghi li t nht 4 h mt ln.
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4.3 B ngm mu , bo dng mu th t rong nc c cc l i ph hp, lm bng v t l iu khng phn ng v i xi mng.
Nhi t ca nc trong b ngm mu c duy tr nhi t (27 1) 0C v c ghi l i t nh t m t ln m i ngy trong gi lm vic.
4.4 Xi mng, ct tiu chun ISO (xem 5.1.3) v nc, dng ch to mu th theo nhit phng th nghim.
4.5 Sng th nghim, loi sng li ph hp vi ISO 3310 1, gm cc kch thc c nu trong Bng 1.
Bng 1 Mt sng th nghim
Kch thc l vung a
mm
2,00 1,60 1,00 0,50 0,16 0,08
a Ly t TCVN 2230:2007 (ISO 565:1990), loi R20
4.6 Thit b
4.6.1 Yu cu chung
Thit b, dng c dng ch to v kim tra mu th theo nhit phng th nghim. ni c nhit dao ng trong di c quy nh, th nhit kim sot ti nn chnh v nhit mc tiu l gi tr gia ca di.
Dung sai th hin trn cc Hnh v t 1 n 5 quan trng cho s vn hnh ng ca thit b trong qu trnh th nghim. Khi kim tra thng xuyn nu dung sai khng p ng th thit b b loi b, iu chnh hoc sa cha. S liu cc ln kim tra phi lu gi li.
Khi nghim thu thit b mi cn kim tra: khi lng, th tch v cc kch thc nh quy nh ca tiu chun ny, c bit ch ti cc kch thc ti hn ca dung sai c quy nh. Trong trng hp vt liu ca thit b c th nh hng n kt qu th nghim th vt liu y phi c ch r.
Cc kch thc xp x th hin trn cc Hnh v nhm hng dn cho cc nh sn xut thit b hoc ngi vn hnh. Cc kch thc bao gm c dung sai l bt buc.
4.6.2 My trn, bao gm cc b phn c bn sau: a) mt ci trn bng thp khng g, c dung tch 5 L, c hnh dng v kch thc in hnh th hin trn Hnh 1, ci c gn vo khung my trn sao cho trong sut thi gian trn an ton c m bo, chiu cao ca ci tng xng vi cnh trn sao cho khe h gia cnh v ci trn c th vi chnh v c nh c.
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b) mt cnh trn bng thp khng g c hnh dng, kch thc v dung sai in hnh th hin trn Hnh 1. Cnh trn chuyn ng quay xung quanh trc ca n do chuyn ng hnh tinh ca n quanh trc ci cc tc c iu khin bi mt ng c in. Hai chiu quay ngc nhau v t s gia hai tc khng phi l mt s nguyn.
Cc cnh v ci trn c lm thnh b v khng c s dng ln ln.
Khe h gia cnh trn v ci trn th hin trn Hnh 1 c kim tra thng xuyn. Khe h (3 1) mm l ng vi v tr khi cnh trn trong ci rng v c chnh st vo thnh ci mc c th. Dng c o dung sai n gin (dng c o khe) c dng nhng ch kh o trc tip. CH THCH: Cc kch thc nh du xp x th hin trn Hnh 1 l hng dn cho cc nh sn xut.
Kch thc tnh bng milimt
CH DN: 1 Ci 2 Cnh trn
Hnh 1 - Ci v cnh trn in hnh
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Khi trn va, my trn vn hnh vi cc tc c nu trong Bng 2.
Bng 2 - Tc ca cnh trn
Tc Chuyn ng quay trn
min-1
Chuyn ng hnh tinh
min-1
Thp 140 5 62 5
Cao 285 10 125 10
4.6.3 Khun Khun gm ba ngn nm ngang sao cho ba mu th hnh lng tr c t i t din ngang 40 mm x 40 mm v di 160 mm c th c chun b cng m t lc. M t k iu thi t k in hnh c th hin trn Hnh 2.
Khun c lm bng thp c thnh dy xp x 10 mm. cng Vicker trn b mt ca mi mt bn trong khun phi t t nht HV 200. Tuy nhin, cng ti thiu HV 400 c khuyn co s dng.
Kch thc tnh bng milimt
a Hng thao tc chuyn ng ca gt va tha.
Hnh 2 - Mt kiu thit k khun in hnh
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Khun c ch to sao cho vic tho mu th ra khi khun c d dng m khng b h hi. Mi khun c mt tm phng bng thp c hay gia cng c kh. Khun khi lp rp phi kht cht v c nh vo tm .
Vic lp rp nh vy m bo khng c gy ra vnh hoc khe h c th nhn thy c trong qu trnh vn hnh. Tm phi tip gip hon ton vi bn ca thit b ln cht v chc chn khng gy ra dao ng ph.
Khun v thit b dn t cc nh sn xut khc nhau c th c cc kch thc bn ngoi v cc khi lng khng tng thch vi nhau, do vy s tng thch ca chng cn c m bo bi ngi s dng.
Mi b phn ca khun c nh s tin cho vic lp rp v m bo ph hp vi cc dung sai quy nh. Cc b phn ging nhau ca cc b khun khc nhau khng lp ln cho nhau.
Khun lp rp phi ph hp vi cc yu cu sau.
a) Kch thc bn trong v dung sai ca mi ngn khun nh sau: chiu di: (160 1) mm; chiu rng: (40,0 0,2) mm; chiu su: (40,1 0,1) mm.
b) Dung sai phng (xem TCVN 5906:2007 (ISO 1101:2004)) trn ton b mi mt bn trong khng ln hn 0,03 mm.
c) Dung sai v vung gc (xem TCVN 5906:2007 (ISO 1101:2004)) ca mi mt trong tng ng vi mt y khun v mt k pha trong ly lm cc mt mc khng ln hn 0,2 mm.
d) Cu to b mt (xem TCVN 5707:2007 (ISO 1302:2002)) ca tng mt bn trong khng nhm hn N8.
Khun c thay khi bt k mt dung sai no vt qu quy nh. Khi lng ca khun phi ph hp vi yu cu v khi lng c t hp trong 4.6.4.
Sau khi lp khun lm sch, sn sng dng, dng mt loi vt liu thch hp trm kn cc mi ni pha ngoi khun. Bi mt lp mng du bi khun ln cc mt bn trong khun.
CH THCH: Mt s loi du c nh hng ti s ng rn ca xi mng; cc loi du gc khong nh l ph hp.
thun tin cho vic khun cn mt phu kim loi va kht c thnh thng ng cao t 20 mm n 40 mm. Khi quan st s lp rp, cc thnh ca phu bao ph cc thnh bn trong ca khun khng qu 1 mm. Thnh ngoi ca phu c nh v m bo ng v tr trn khun.
ri v gt bt va tha cn c hai bay v mt thanh gt kim loi cnh thng sc c hnh dng c th hin trn Hnh 3.
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Kch thc tnh bng milimt
CH DN:
D chiu cao ca phu
Hnh 3 Bay v thanh gt kim loi in hnh
4.6.4 Thit b dn, gm mt bn hnh ch nht c gn cht bng hai tay n nh vo mt trc quay cch tm bn 800 mm. Mt kiu thit k in hnh c th hin trn Hnh 4.
Bn c gn tm mt di ca n mt vu ni mt trn. Bn di vu ni ny phi c mt cht hm nh c mt trn phng. v tr ngh, php tuyn chung i qua im tip xc gia vu v cht hm phi thng ng. Khi vu ni t ln cht hm th mt nh ca bn phi nm ngang sao cho mc phng ca mt trong bn gc bt k khng chnh qu mc phng trung bnh l 1,0 mm. Bn phi c cc kch thc bng hoc ln hn cc kch thc ca tm khun v mt trn bn phi c bo my. Cc kp dng gn cht khun vi bn phi c cp km theo thit b. Khi lng t hp ca bn, bao gm c tay n, khun rng, phu v kp l (20,0 0,5) kg.
a) Bay ln b) Bay nh
c) Thanh gt kim loi
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Kch thc tnh bng milimt
CH DN: 1 Vu 2 C cu ph cam 3 Cam 4 Cht hm
Hnh 4 Thit b dn in hnh
Cc tay n ni b lp rp bn vo trc quay phi cng v lm bng ng trn c ng knh ngoi t 17 mm n 22 mm c chn t cc kch thc ng ph hp vi ISO 4200. Tng khi lng ca hai tay n bao gm c lin kt ngang l (2,25 0,25) kg. Cc gi trc quay phi l loi hnh cu hoc loi con ln v c bo v trnh xm nhp ca sn v bi. S di chuyn ngang khi tm bn do hot ng ca trc quay khng c vt qu 1,0 mm. Vu v cht hm phi lm bng thp c cng Vicker t nht HV 500. cong ca vu khong 0,01 mm-1.
Khi vn hnh bn c nng ln bi cam v c ri t do t cao (15,0 0,3) mm trc khi vu p vo cht hm.
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Cam c lm bng thp c cng Vicker t nht HV 400 v trc ca n phi lp trn vng bi t la c thit k sao cho lun ri t do t cao (15,0 0,3) mm. C cu ph ca cam phi m bo cho cam t b mn nht. Cam c iu khin bi mt ng c in khong 250 W thng qua mt hp gim tc vi tc u mt vng trn giy. Mt c cu iu khin v mt b m phi c cp km theo thit b m bo chnh xc 60 ln dn c thc hin trong mt chu k dn (60 3) s. V tr ca khun trn bn c t sao cho chiu di ca cc ngn khun thng hng vi chiu di ca tay n v vung gc vi trc quay ca cam. Cc du hiu chun thch hp phi c cp km theo thit b d dng nh v khun sao cho tm ca ngn gia khun va nm ng trn im p.
Thit b dn c lp rp chc chn trn mng b tng c khi lng khong 600 kg, th tch khong 0,25 m3 v c cc kch thc m bo chiu cao lm vic thch hp cho khun. Ton b ca mng b tng c t trn mt m n hi, v d nh m bng cao su t nhin, c cch ly hu hiu ngn c cc dao ng bn ngoi nh hng n mc ln cht.
ca thit b dn c gn vo b tng bng cc bu lng neo v mt lp va mng c ri vo gia lp thit b dn v b tng m bo mt tip gip ton b v khng b dao ng.
4.6.5 Dng c th cng un (khng bt buc), c kh nng to ra ti trng n 10 kN vi chnh xc 1,0 % ca ti trng c ghi nm khong bn phn nm pha trn ca di o ang dng, tc tng ti (50 10) N/s. CH THCH 1: Dng c th cng un l khng bt buc. Nu ch cng nn c o, cc thanh mu hnh lng tr c th c b gy i bng cc bin php thch hp khc m khng gy ra ng sut c hi cho cc na thanh mu hnh lng tr.
CH THCH 2: Cng un c th o bng my th cng un hoc bng mt thit b thch hp trong my th cng nn.
Dng c phi c cp cng vi mt b g un gm hai gi ta dng con ln lm bng thp ng knh (10,0 0,5) mm, t cch nhau (100,0 0,5) mm v mt con ln chu ti th ba bng thp c cng ng knh, c t chnh gia hai con ln kia. Chiu di cc con ln khong t 45 mm n 50 mm. B tr ti trng th cng un c th hin trn Hnh 5.
Ba mt thng ng xuyn qua cc trc ca ba con ln phi song song vi nhau v phi duy tr c tnh song song, cch u nhau v cng vung gc vi chiu nm ca mu th trong lc th. Mt trong cc con ln gi ta v con ln ti trng phi c cn cht t m bo s phn b ng u ca ti trn c chiu rng ca mu th m khng gy ra ng sut xon.
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Kch thc tnh bng milimt
Hnh 5 - B tr ti trng th cng un
4.6.6 My th cng nn, xc nh cng nn phi c kh nng thch hp cho th nghim (xem on 8 ca iu ny), vi chnh xc 1,0 % ca ti trng c ghi nm khong bn phn nm pha trn ca di o ang dng khi c kim nh ph hp vi ISO 7500 1.
My phi m bo c tc tng ti (2400 200) N/s. My phi c ni vi mt phn ch lc k, b phn ny c ch to sao cho tr s bo khi mu b ph hu vn c hin th sau khi my c d ti. Vic ny c th thc hin c bng cch dng dng c ch lc k ti a da trn cch o p sut hoc mt b nh trn mn hnh hin s. Cc my nn iu chnh mc tng ti bng tay phi c lp mt dng c o tc d dng kim tra mc tng ti.
Trc thng ng ca pittng phi trng vi trc thng ng ca my v trong thi gian gia ti, chiu di chuyn ca pittng phi dc theo trc thng ng ca my. Mt khc, hp lc phi i qua tm mu th. B mt tm p di ca my phi vung gc vi trc my v duy tr c tnh vung gc trong sut thi gian gia ti.
Tm gi cu ca tm p trn phi nm giao im ca trc thng ng ca my vi b mt di ca tm p trn, vi sai lch 1 mm. Tm p trn c t do thng tu theo s tip xc vi mu th, nhng trong thi gian gia ti v tr tm p trn v di phi c c nh.
Cc tm p ca my c lm bng vt liu vonfam cacbit, hoc c th thay th bng thp c cng Vicker t nht HV 600. Cc tm p ny c chiu dy t nht 10 mm, rng (40,0 0,1) mm v di (40,0 0,1) mm. Dung sai phng ph hp vi TCVN 5906:2007 (ISO 1101:2004) trn ton b b mt tip xc vi mu th khng ln hn 0,01 mm. Cu to b mt ph hp vi TCVN 5707:2007 (ISO 1302:2002) khng nhn hn N3 v khng nhm hn N6.
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Cng c th dng hai m p ph bng vt liu vonfam cacbit hoc thp c cng Vicker t nht HV 600, dy t nht 10 mm v ph hp vi cc yu cu v tm p. Hai m p ph c ch to sao cho tm ca chng tng xng vi trc ca h thng truyn ti vi chnh xc 0,5 mm. Hai m p ph phi thng nhau vi sai lch khng ln hn 0,5 mm tnh t tm ca chng.
Trng hp my th khng c g i cu, hoc g i cu b k t hay ng knh g i cu ln hn 120 mm th s dng m t g nh v theo 4.6.7.
My th c hai hay nhiu cp ti trng. Gi tr cao nht ca cp ti trng di tt nht xp x bng mt phn nm gi tr cao nht ca cp ti trng cao hn lin k.
My th tt nht c thao tc t ng iu chnh tc tng ti vi b phn ghi kt qu.
Gi cu ca my cn c tra du d iu chnh khi tip xc vi mu th, nhng cng ch trong chng mc khng xy ra chuyn dch ca tm p khi gia ti trong qu trnh th nghim. Khng nn dng loi du nhn b nh hng di p sut cao.
Cc thut ng thng ng, di, trn l dng cho cc thit b th thng thng m thng t la c theo trc thng ng. Tuy nhin, thit b c trc khng thng ng cng vn c php s dng.
4.6.7 G nh v cho my th cng nn (khi c yu cu bi 4.6.6), c t gia cc tm p ca my truyn ti t my sang b mt nn ca mu th (xem Hnh 6). G nh v c mt tm p di v n c th c gn vi tm p di ca my. Tm p trn ca g nh v nhn ti t tm p trn ca my qua mt gi cu trung gian. Gi ny l mt phn ca ton b c cu v c th trt theo chiu thng ng m khng gy ma st ng k trong g nh v theo hng chuyn ng ca n. G nh v phi c gi sch s v gi cu phi quay c d dng sao cho tm p khp vi hnh dng mu th v sau c c nh trong sut thi gian th. Khi s dng g nh v phi tun theo cc yu cu c nu trong 4.6.6.
Gi cu ca g nh v c th c tra du nhng ch va trnh s dch chuyn ca tm p khi gia ti trong sut thi gian th. Khng nn dng loi du nhn b nh hng di p sut cao.
CH THCH: Tt nht l ton b c cu phi t ng tr v c v tr ban u sau khi ph hu mu th.
4.6.8 Cn, c kh nng cn vi chnh xc n 1 g.
4.6.9 Dng c o thi gian, c kh nng o vi chnh xc n 1 s.
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CH DN:
1 Gi cu ca my
2 Tm p trn ca my
3 L xo tr v
4 Vng bi
5 C cu trt thng ng
6 Gi cu ca g nh v
7 Tm p trn ca g nh v
8 G nh v
9 Mu th
10 Tm p di ca g nh v
11 Tm p di ca my
Hnh 6 G nh v in hnh cho my th cng nn
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5 Thnh phn va
5.1 Ct
5.1.1 Khi qut
Ct tiu chun ISO c sn xut cc quc gia khc nhau s dng xc nh cng xi mng ph hp vi tiu chun ny phi tun theo cc yu cu c nu trong 5.1.3.
Do kh khn trong vic m t ct tiu chun ISO mt cch y , nn khi chng nhn chng phi so vi ct chun ISO c quy nh trong 5.1.2 bng th nghim xc nhn cht lng ban u, th nghim thm tra v th nghim ph hp hng nm nh quy nh trong iu 11.
5.1.2 Ct chun ISO
Ct chun ISO, c mt tr lng d tr nht nh c duy tr nh vt liu chun, l loi ct t nhin, giu silc, gm cc ht trn cnh vi hm lng silic ioxyt t nht l 98 %.
Cp phi ht nm trong gii hn quy nh c nu trong Bng 3.
Bng 3 - Cp phi ht ca ct chun ISO
Kch thc mt sng l vung, mm 2,00 1,60 1,00 0,50 0,16 0,08
Lng st tch lu, % 0 7 5 33 5 67 5 87 5 99 1
CH THCH: Ct chun ISO l ct chun CEN (u ban Chu u v tiu chun ho). Thng tin v ct chun CEN c th nhn c t Hip Hi Thnh Vin ISO c, DIN, Postfach 1107, D 1000 Berlin 30.
5.1.3 Ct tiu chun ISO
Ct tiu chun ISO phi c cp phi ht theo quy nh trong 5.1.2, c xc nh bng vic phn tch sng trn mt mu ct i din c khi lng khng nh hn 1345 g. Vic sng phi tin hnh lin tc cho n khi lng ct lt qua mi sng nh hn 0,5 g/min.
Hm lng m nh hn 0,2 %, c xc theo khi lng mt ca mt mu ct i din sau khi sy nhit t 105 0C n 110 0C ti khi lng khng i v biu th bng phn trm khi lng mu sy kh.
Trong sut qu trnh sn xut, vic xc nh ny phi c tin hnh t nht mt ln mi ngy. Nhng yu cu ny cha m bo ct tiu chun ISO tng ng vi ct chun ISO. S tng ng phi c bt u v duy tr bng th nghim chng nhn c quy nh trong iu 11.
Ct tiu chun ISO phi c ng gi trong cc ti vi khi lng (1350 5) g; loi vt liu lm ti khng nh hng n kt qu th cng v ct trong mi ti phi c cp phi ht theo quy nh trong 5.1.2.
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Ct tiu chun ISO phi c bo qun cn thn trnh h hi hoc nhim bn, c bit vi mi trng m trc khi s dng.
5.2 Xi mng
Xi mng ang c th nghim c th tip xc vi mi trng khng kh trong thi gian ti thiu c th. Trong trng hp cn thit lu hn 24 h k t lc ly mu n lc tin hnh th nghim, th phi lu gi hon ton y trong cc thng kn c lm t vt liu khng phn ng vi xi mng.
Mu phng th nghim phi c ng nht bng my hoc cc phng tin khc, trc khi ly mu i din cho th nghim.
5.3 Nc
Nc ct hoc nc kh ion s dng cho cc th nghim chng nhn. Cn i vi cc th nghim khc, c th s dng nc ung. Trong trng hp c khiu ni hoc tranh chp, s dng nc ct hoc nc kh ion.
6 Chun b va
6.1 Thnh phn va
T l theo khi lng bao gm mt phn xi mng (5.2), ba phn ct tiu chun ISO (5.1), v mt na phn l nc (5.3) (t l nc/xi mng l 0,50). Mi m va cho ba mu th gm: (450 2) g xi mng, (1350 5) g ct v (225 1) g nc.
6.2 Trn va
Cn xi mng v nc bng cn (4.6.8). Khi thm nc, cho mt cch nh git bng dng c c kh nng o th tch chnh n 1 ml. Mi m va c trn bng my trn (4.6.2). Thi gian ca cc giai on trn khc nhau bao gm c thi gian m/tt cng tc my trn v c tnh chnh xc trong phm vi sai lch 2 s.
Qui trnh trn va c tin hnh nh sau.
a) nc vo ci v thm xi mng mt cch cn thn trnh mt nc hoc xi mng. b) Ngay khi nc v xi mng tip xc vi nhau, khi ng ngay my trn tc thp (xem Bng 2), trong khi bt u tnh thi gian ca cc giai on trn, ng thi ghi li thm thi im ly n pht gn nht lm thi im khng. Sau 30 s trn, thm ct t t trong sut 30 s tip theo. Bt my trn tc cao (xem Bng 2) v tip tc trn thm 30 s. CH THCH: Thi im khng l mc tnh ton thi gian tho khun (xem 8.2) v tui th cng (xem 8.4).
c) Dng my 90 s. Trong 30 s u, dng bay cao su hoc nha co va bm thnh v y ci vun vo gia ci.
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d) Tip tc trn tc cao thm 60 s. Qui trnh trn c th c iu khin t ng hoc th cng.
7 Chun b mu th
7.1 Kch thc mu th
Mu th hnh lng tr c kch thc 40 mm x 40 mm x 160 mm.
7.2 c mu th
Tin hnh c mu th ngay sau khi chun b xong va. Khun v phu c kp cht vo bn dn, dng mt xng nh thch hp, xc mt hoc vi ln ri lp va u tin cho mi ngn khun (mi ln khong 300 g), ly trc tip t my trn. Dng bay ln (xem Hnh 3) ri ng u, bay c gi gn nh thng ng vi vai ca n tip xc vi nh phu v c y ln pha trc v pha sau dc theo mi ngn khun. Sau ln lp va u tin bng cch dn 60 ln bng thit b dn (4.6.4). Cho thm lp va th hai, m bo phi c lng va tha nh ln b mt thnh khun, dng bay nh (xem Hnh 3) dn u mt va ri ln lp va ny bng cch dn thm 60 ln.
Nh nhng nhc khun khi bn dn v tho phu ra. Ngay sau , gt b va tha bng thanh kim loi (xem Hnh 3), thanh ny c gi gn nh thng ng nhng nghing theo hng gt. Chuyn ng t t theo kiu ca ngang mi chiu mt ln. Lp li qui trnh gt b va tha bng cch nghing thm thanh kim theo hng gt lm nhn b mt.
CH THCH: S ln chuyn ng ca v mc nghing ca thanh kim loi ph thuc vo do ca va; va qunh hn yu cu s ln chuyn ng ca v mc nghing nhiu hn; s ln chuyn ng ca lm nhn b mt t hn khi gt va tha (xem Hnh 2).
Lau sch va bm ngoi khun kt thc vic gt b va tha.
Ghi nhn hoc nh du cc khun nhn bit mu th.
8 Bo dng mu th
8.1 X l v ct gi mu th trc khi tho khun y mt tm knh, thp hoc vt liu khng thm khc m khng phn ng vi xi mng c kch thc xp x 210 mm x 185 mm x 6 mm ln khun.
CNH BO AN TON - m bo an ton cn dng cc tm knh c cnh c mi.
t ngay cc khun c y ln gi nm ngang trong phng hoc t dng h (xem 4.2). Hi m phi tip xc u vi cc mt bn ca khun. Khun khng c chng cht ln nhau. Mi khun phi c ly khi ni ct gi vo thi im thch hp cho vic tho khun.
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8.2 Tho khun Vic tho khun phi thn trng trnh gy h hi cho cc mu th. Khi tho khun c th s dng ba bng cao su hoc cht do, hay cc dng c ch to c bit. i vi cc php th tui 24 h, vic tho khun khng c trc qu 20 min trc khi mu th c th. i vi cc php th tui ln hn 24 h, vic tho khun tin hnh trong khong 20 h v 24 h sau khi c mu.
Vic tho khun c th sau 24 h nu nh tui 24 h va cha cng yu cu trnh h hng mu th. Phi ghi li vic tho khun mun trong bo co th nghim.
Cc mu th tho khi khun v c chn th vo lc 24 h (hoc 48 h khi vic tho khun mun l cn thit), c ph bng vi m cho ti lc th. Cn cc mu th c chn ngm trong nc, c nh du bng mc chu nc hoc bt sp mu trc khi ngm tin nhn bit sau ny.
kim tra vic trn, ln cht v hm lng bt kh trong va nn tin hnh cn mu th sau khi tho khun.
8.3 Bo dng mu th trong nc
Cc mu th c nh du c ngm ngp ngay trong nc, nm ngang hay thng ng tu theo cch no thun tin, nhit (27 1) 0C trong cc b ngm mu (4.3). Nu ngm mu nm ngang th cc mt bn thnh c theo ng hng thng ng v mt gt va ln.
t mu th trn li (xem 4.3) cch xa nhau sao cho nc c th vo c c su mt mu th. Trong thi gian ngm, khng c lc no khong cch gia cc mu th hay su ca nc trn b mt mu th nh hn 5 mm.
Vic ngm ring l bt buc, tr phi xc nh c qua thc nghim l thnh phn ca xi mng ang th nghim khng nh hng ti s pht trin cng ca xi mng khc c ngm chung; xi mng c cha hm lng ion clo ln hn 0,1 % phi ngm ring.
Dng nc my b ln u v thnh thong thm nc gi cho mc nc khng thay i. Trong thi gian ngm mu th, khng c thay qu 50 % lng nc mi ln thay nc.
H thng tun hon nc c lp t trong b ngm mu s m bo cho nhit ngm mu th c ng nht; nu c mt h thng nh vy lu thng trong b ngm mu th s dng tc chy nh nht c th v khng gy ra s chuyn ng hn lon c th quan st bng mt.
Ly mu th cn th bt k tui no (ngoi tr tui 24 h hoc 48 h khi tho khun mun) ra khi nc khng c trc qu 15 min trc khi tin hnh th. Loi b cc cht lng ng trn cc b mt mu th. Dng vi m ph ln mu th cho ti lc th.
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8.4 Tui mu th th cng
Tnh tu i mu th k t th i im khng (xem 6.2). Tin hnh th cng cc tu i sai s nh sau:
24 h 15 min;
48 h 30 min;
72 h 45 min;
7 d 2 h;
28 d 8 h.
9 Cch tin hnh
9.1 Cng un
Dng phng php gia ti ti ba im xc nh cng un bng mt trong cc loi dng c quy nh trong 4.6.5.
t mu th lng tr vo trong dng c (4.6.5) vi mt mt bn ta trn cc con ln gi ta v trc dc ca mu th vung gc vi cc gi ta. t ti trng theo chiu thng ng bng con ln ti trng vo mt i din ca lng tr v tng ti trng t t vi tc (50 10) N/s cho n khi mu gy i.
Ph vi m ln cc na lng tr cho n khi th cng nn.
Cng un, Rf, tnh bng megapascal (MPa), theo Cng thc (1):
3
5,1b
lFR ff
= (1)
trong :
b l cnh tit din vung ca lng tr tnh bng milimt (mm); Ff l ti trng t ln gia lng tr lc gy, tnh bng niu tn (N); l l khong cch gia cc gi ta tnh bng milimt (mm).
9.2 Cng nn
Tin hnh th trn cc na lng tr gy nh quy nh trong 9.1 hoc s dng cc bin php thch hp khc m khng gy ng sut c hi cho cc na lng tr.
Th mi na lng tr gy bng cch t ti ln cc mt bn tip xc vi thnh khun s dng thit b quy nh trong 4.6.6 v 4.6.7.
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t mt bn cc na lng tr vo chnh gia tm p ca my vi sai lnh khng qu 0,5 mm v t nm dc sao cho mt cui lng tr nh ra ngoi tm p hoc m p ph khong 10 mm. Tng ti trng t t vi tc (2400 200) N/s trong sut qu trnh th cho n khi mu th b ph hu.
Nu tng ti trng bng tay th cn iu chnh chng li khuynh hng gim tc tng ti khi gn ti ti trng ph hu.
Cng nn, Rc, tnh bng megapascal (MPa), theo Cng thc (2):
1600c
c
FR = (2)
trong :
cF l ti trng ti a lc mu th b ph hu, tnh bng niu tn (N); 1600 l din tch tm p hoc m p ph (40 mm x 40 mm), tnh bng milimt vung
(mm2).
10 Kt qu th nghim
10.1 Cng un
10.1.1 Tnh ton v biu th kt qu
Kt qu th cng un l gi tr trung bnh s hc ca ba ln xc nh cng un ring bit, mi gi tr ly chnh xc n 0,1 MPa, nhn c trn mt b ba mu th lng tr.
Kt qu trung bnh ly chnh xc n 0,1 MPa.
10.1.2 Bo co kt qu th nghim
Ghi li tt c cc kt qu ring bit. Bo co gi tr trung bnh tnh ton.
10.2 Cng nn
10.2.1 Tnh ton v biu th kt qu
Kt qu th cng nn l gi tr trung bnh s hc ca su kt qu xc nh cng nn ring bit, mi gi tr ly chnh xc n 0,1 MPa, nhn c t su na lng tr gy trn mt b ba mu th lng tr.
Nu mt kt qu trong s su ln xc nh vt qu 10 % so vi gi tr trung bnh th loi b kt qu v ch tnh gi tr trung bnh ca nm kt qu cn li. Nu mt trong nm kt qu ny vt qu 10 % gi tr trung bnh ca chng th loi b ton b kt qu v lp li php th.
Kt qu trung bnh ly chnh xc n 0,1 MPa.
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10.2.2 Bo co kt qu th nghim
Ghi li tt c cc gi tr ring bit. Bo co gi tr trung bnh tnh ton v bt k mt kt qu loi b no theo 10.2.1.
10.2.3 nh gi chnh xc ca phng php th cng nn
10.2.3.1 lp li ngn hn
lp li ngn hn ca phng php th cng nn a ra chm gia cc kt qu th nghim thu c trn nhng mu xi mng ging ht nhau trn danh ngha, s dng cng loi ct tiu chun ISO c th trong cng phng th nghim, bi cng cn b th nghim s dng cng thit b trong khong thi gian ngn. Trong trng hp xc nh cng nn tui 28 d, lp li ngn hn t c i vi k nng bnh thng theo cc iu kin trn khi c biu th nh mt h s bin thin, phi nh hn 2,0 %.
CH THCH: Thc nghim cho thy rng c th t c k nng tt hn v c th gp u n trong mt s phng th nghim. N tng ng vi mt gi tr khi c biu th nh mt h s bin thin l 1 % i vi lp li ngn hn.
lp li ngn hn l thc o chnh xc ca phng php th dng cho th nghim chng nhn ct tiu chun ISO v cc thit b ln cht thay th khc.
10.2.3.2 lp li di hn
lp li di hn ca phng php th cng nn a ra chm gia cc kt qu th nghim thu c t nhng th nghim thng xuyn ca cc mu xi mng khc nhau c ly t cng mu xi mng c ng nht, c th trong cng phng th nghim, trong cc iu kin sau: cn b th nghim c th khc nhau, cc thit b c th khc nhau, cng loi ct tiu chun ISO v din ra trong sut cc chu k thi gian di (ti mt nm). Trong trng hp xc nh cng nn tui 28 d, lp li di hn t c i vi k nng bnh thng theo cc iu kin trn khi c biu th nh mt h s bin thin, phi nh hn 3,5 %.
CH THCH: Thc nghim cho thy rng c th t c k nng tt hn v c th gp u n trong mt s phng th nghim. N tng ng vi mt gi tr khi c biu th nh mt h s bin thin l 2,5 % i vi lp li di hn.
lp li di hn l thc o chnh xc ca phng php th dng cho th nghim t ng - kim sot ca xi mng hoc th nghim thm tra hng thng ct tiu chun ISO, v nh gi chnh xc ca phng th nghim theo thi gian.
10.2.3.3 ti lp
ti lp ca phng php th cng nn a ra chm gia cc kt qu th nghim thu c trn nhng mu xi mng ging ht nhau trn danh ngha, c th trong cc phng th
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nghim khc nhau trong cc iu kin sau: cn b th nghim khc nhau, thit b khc nhau, ct tiu chun ISO c th khc nhau v c th cc thi im khc nhau.
Trong trng hp xc nh cng nn tui 28 d, ti lp gia cc phng th nghim t c i vi k nng bnh thng theo cc iu kin trn khi c biu th nh mt h s bin thin, phi nh hn 4,0 %.
CH THCH: Thc nghim cho thy rng c th t c k nng tt hn v c th gp u n trong mt s phng th nghim. N tng ng vi mt gi tr khi c biu th nh mt h s bin thin l 3 % i vi ti lp.
ti lp l thc o chnh xc ca phng php th dng nh gi s ph hp ca xi mng hoc ct tiu chun ISO.
11 Th nghim chng nhn ct tiu chun ISO v thit b ln cht thay th
11.1 Khi qut
Mt loi ct tiu chun ISO tun theo 5.1.3 hoc mt thit b ln cht thay th khc c th c s dng theo iu 3 vi iu kin cc kt qu cng xi mng khng sai khc ng k so vi cc kt qu thu c khi s dng ct chun ISO (5.1.2) hoc thit b dn (4.6.4) v qui trnh chun, tng ng.
Trong 11.2 v 11.3, quy nh cc iu kin trong trng hp cc loi ct tiu chun ISO v cc thit b ln cht thay th, tng ng c chng nhn. Vic chng nhn phi do mt t chc ph hp cp v c da trn cc kt qu th nghim c tin hnh bi mt phng th nghim.
Ngi dng tiu chun ny nn xem xt vic s dng phng php nh gi ph hp tho ng i vi cc yu cu ca tiu chun ny. Chng ch c cp bi mt t chc c lp th ba t mc tin cy cao hn vo s ph hp ca cc sn phm v cc qu trnh sn xut.
Cc phng th nghim c ch nh phi ph hp vi TCVN ISO/IEC 17025 v d kin c tham gia vo cc chng trnh th nghim thnh tho m bo rng th nghim chng nhn l da vo mc th nghim so snh.
Cc phng php th nghim c quy nh v c p dng l da trn so snh cc kt qu th cng nn tui 28 d.
11.2 Th nghim chng nhn ct tiu chun ISO
11.2.1 Nguyn tc
Th nghim chng nhn ct tiu chun ISO bao gm:
a) th nghim xc nhn cht lng ban u; b) th nghim thm tra;
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c) th nghim ph hp hng nm. Th nghim xc nhn cht lng ban u c quy nh trong 11.2.2.1 v th nghim ph hp hng nm c quy nh trong 11.2.2.2 vi iu kin cc yu cu trong 11.2.3.3 c p ng, ct s c chng nhn l ang ph hp vi tiu chun ny.
Th nghim thm tra ct tiu chun ISO c quy nh trong 11.2.4 vi iu kin cc yu cu trong 11.2.5.3 c p ng. Th nghim thm tra m bo rng mt loi ct tiu chun ISO c chng nhn vn cn ph hp vi tiu chun ny. H s ca cc kt qu th nghim thm tra c lu gi v c thanh tra coi nh mt phn ca th nghim ph hp hng nm.
Ct c chng nhn c ch nh l ct tiu chun ISO.
11.2.2 Th nghim xc nhn cht lng ct tiu chun ISO
11.2.2.1 Th nghim xc nhn cht lng ban u
Trc khi th nghim xc nhn cht lng ban u nh my phi ang sn xut n nh.
Trong mt chu k sn xut t nht l ba thng, ba mu ct c lp c ly ti thi im xut hng bi t chc chng nhn. S lng ti ly trong mi mu c tnh ton sao cho cung cp s lng ct yu cu bi phng php th nghim ph hp vi 11.2.3.1. Ngoi ra, s lng ca mt trong ba mu phi ln cung cp s lng ct c yu cu bi phng php th nghim thm tra ph hp vi 11.2.5.1 mt chu k t nht l mt nm. thc hin mc ch , mu ny c chia nh bi t chc chng nhn v mu i din s dng cho th nghim thm tra c lu ring r bi nh sn xut.
Tng mu mt trong ba mu ct c th nghim so vi ct chun ISO, p dng phng php quy nh trong 11.2.3, dng mt trong ba loi xi mng c mc chun khc nhau c la chn cho mc ch . Cc th nghim phi c tin hnh trong mt phng th nghim c ch nh (xem 11.1). Trong trng hp tng kt qu mt trong s cc kt qu thu c t ba mu biu th theo 11.2.3.2 p ng cc yu cu trong 11.2.3.3, ct s c chng nhn.
11.2.2.2 Th nghim ph hp hng nm
Vic chng nhn tip tc ct tiu chun ISO phi cn c vo kt qu t cc hnh ng sau:
a) tin hnh thanh tra cc h s th nghim thm tra ph hp vi 11.2.4 vi iu kin p ng cc yu cu trong 5.1.3 v 11.2.5.3;
b) th nghim bi phng th nghim c ch nh (xem 11.1) ca mt mu ct ngu nhin so vi ct chun ISO, p dng phng php c quy nh trong 11.2.3, dng xi mng poc lng PC 40 hoc PC 50.
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Mt mu ct ngu nhin c ly ti thi im xut hng bi t chc chng nhn. S lng ti ly c tnh ton sao cho s lng ct yu cu bi phng php th nghim theo 11.2.3.1 v phng php th nghim thm tra theo 11.2.5.1 mt chu k t nht l mt nm. thc hin mc ch , mu ny c chia nh bi t chc chng nhn v mu i din cho th nghim thm tra c lu ring r bi nh sn xut.
Ct s c chng nhn trong trng hp:
cc kt qu th nghim thm tra p ng cc yu cu trong 5.1.3 v 11.2.5.3; v
cc kt qu th nghim ph hp hng nm p ng cc yu cu trong 11.2.3.3.
11.2.3 Phng php th nghim chng nhn
11.2.3.1 Cch tin hnh
Chun b 20 cp m va dng cng mt mu xi mng c la chn (xem 11.2.2.1 v 11.2.2.2). S dng ct ang c chng nhn cho mt m cn m kia dng ct chun ISO. Chun b hai m mi cp theo th t ngu nhin, m n k tip m kia, ph hp vi tiu chun ny.
Th cng nn cc mu lng tr tui 28 d v ghi li tt c cc kt qu ring bit
11.2.3.2 Tnh ton v biu th kt qu
i vi mi cp ca cc m, tnh ton v biu th cc kt qu cng nn ph hp vi 10.2.1 v bo co chng ph hp vi 10.2.2, ly x ch kt qu thu c vi ct ang c chng nhn v y ch kt qu thu c vi ct chun ISO.
Tinh ton h s bin thin i vi tng b ca hai b kt qu v kim tra xem chng c p ng ch tiu lp li ngn hn quy nh trong 10.2.3.1.
Nu hai b kt qu khng p ng yu cu ny loi b ton b kt qu v lp li ton b qui trnh th.
Nu mt b kt qu khng p ng yu cu ny tip tc lm nh sau:
a) tnh gi tr trung bnh ca 20 kt qu, x v y ;
b) tnh lch chun ca 20 kt qu, s ; c) tnh chnh lch s hc gia tng kt qu v gi tr trung bnh, b qua du; d) trong trng hp mt trong cc chnh lch ny ln hn s3 , loi b ton b kt qu tng ng v tnh gi tr trung bnh ca 19 kt qu cn li; trong trng hp hai hoc nhiu hn cc chnh lch ny ln hn 3 s , loi b ton b kt qu v lp li ton b qui trnh th; trong trng hp khng c chnh lch no ln hn 3 s , ly c 20 kt qu.
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Tnh ton tiu chun chng nhn, D, biu th bng % s dng Cng thc (3):
( ) 100=y
yxD (3)
trong :
x l gi tr trung bnh ca cc kt qu thu c vi ct ang c chng nhn, tnh bng megapascal (MPa);
y l gi tr trung bnh ca cc kt qu thu c vi ct chun ISO, tnh bng megapascal
(MPa). Bo co D ly chnh xc n 0,1 %, b qua du.
11.2.3.3 Yu cu
chng nhn mt loi ct ph hp vi qui trnh th nghim xc nhn cht lng ban u (xem 11.2.2.1), mi mt gi tr trong ba gi tr tiu chun chng nhn, D, c tnh ton v biu th ph hp vi 11.2.3.2 phi nh hn 5,0 %. Trong trng hp c mt hoc nhiu hn cc gi tr D tnh ton c bng hoc ln hn 5,0 %, th ct khng c chng nhn.
chng nhn mt loi ct tiu chun ISO ph hp vi qui trnh th nghim ph hp hng nm (11.2.2.2), gi tr tiu chun chng nhn, D, c tnh ton v biu th ph hp vi 11.2.3.2, phi nh hn 5,0 %. Trong trng hp gi tr D tnh ton c bng hoc ln hn 5,0 %, ct tiu chun ISO khng c chng nhn, phi tm c nguyn nhn v qui trnh th nghim xc nhn cht lng ban u (11.2.2.1) s c thc hin li cho mt chng nhn thm.
11.2.4 Th nghim thm tra ct tiu chun ISO
Mc ch chng minh mt loi ct tiu chun ISO vn cn ph hp vi tiu chun ny, nh sn xut ct phi t ng tin hnh tip cc th nghim kim sot bao gm:
a) th nghim hng ngy cp phi ht v m ph hp vi 5.1.3; b) th nghim hng thng ph hp vi 11.2.5 ca mt mu ct tiu chun ISO sn xut so vi cng mu ct tiu chun ISO dng cho th nghim xc nhn cht lng ban u hoc th nghim ph hp hng nm (xem 11.2.2.1 v 11.2.2.2). thc hin mc ch , cc mu phi c ly bi nh sn xut ti thi im xut hng, mt ln mt ngy i vi th nghim hng ngy v mt ln mt thng i vi th nghim hng thng.
Nh sn xut ct phi kim tra rng cc yu cu trong 5.1.3 v 11.2.5.3 c p ng v phi xem xt cc kt qu khng ph hp nu c.
Cc kt qu th nghim c ghi li lp thnh h s v lu gi t nht l 3 nm.
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11.2.5 Phng php th nghim thm tra ct tiu chun ISO
11.2.5.1 Cch tin hnh
Chun b 10 cp m va s dng mt mu xi mng c la chn nh quy nh trong 11.2.2.2 b). S dng mu ly mt thng mt ln (11.2.4) cho mt m v mu ly mt nm mt ln cho th nghim xc nhn cht lng ban u hoc th nghim ph hp hng nm (11.2.2.1 v 11.2.2.2) cho m kia. Chun b hai m trong mi cp theo th t ngu nhin, m n k tip sau m kia, ph hp vi tiu chun ny.
Th cng nn cc mu lng tr tui 28 d v ghi li tt c cc kt qu ring bit.
11.2.5.2 Tnh ton v biu th kt qu
i vi tng cp ca cc m, tnh ton v biu th kt qu cng nn ph hp vi 10.2.1 v bo co chng ph hp vi 10.2.2, ly x ch kt qu thu c vi mu c ly mt thng mt ln v y kt qu thu c vi mu c ly mi nm mt ln.
Tnh ton h s bin thin cho tng b ca hai b kt qu v p dng qui trnh trong 11.2.3.2 vo 10 cp ca cc m va.
CH THCH: Trong trng hp mt b kt qu khng p ng c cc yu cu ch tiu lp li ngn hn, qui trnh trnh by trong 11.2.3.2 c thc hin da trn cc b gm 10 kt qu gim xung mc ti thiu cn 9 kt qu dng vo mc ch nh gi da trn 11.2.3.2 d).
Tnh ton v bo co tiu chun chng nhn, D, nh quy nh trong 11.2.3.2.
11.2.5.3 Yu cu
Trong mt lot 12 th nghim hng thng lin tip, gi tr tiu chun chng nhn, D, c tnh ton v biu th ph hp vi 11.2.5.2 khng c vt 2,5 % qu hai ln. Nu c nhiu hn hai gi tr D ln hn 2,5 %, phi tm c nguyn nhn v qui trnh th nghim xc nhn cht lng ban u s c thc hin li cho chng nhn thm.
11.2.6 Bo co
Cc nh sn xut ct tiu chun ISO phi lm sn cho ngi mua mt bo co chi tit khi c yu cu gm:
a) ngy sn xut; b) tn v a ch ng k ca nh sn xut; c) ngy xc nhn cht lng ban u ca ct; d) ngy th nghim ph hp hng nm gn y nht; e) tn v a ch ng k phng th nghim c ch nh; f) xc nhn cc kt qu th nghim ch ra rng ct sn xut tun theo cc yu cu ca tiu chun ny v iu kin l ct tiu chun ISO.
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11.3 Th nghim chng nhn thit b ln cht thay th
11.3.1 Yu cu chung
Trong trng hp th nghim chng nhn thit b ln cht thay th c yu cu, cc ti liu sau y phi c tp hp a vo h s gm:
a) m t y qui trnh ln cht; b) m t y thit b ln cht (thit k v cu to); c) hng dn bo dng, bao gm c danh mc kim tra m bo vn hnh ng. thc hin chng nhn thit b ln cht thay th, ba b thit b sn c trn th trng c la chn v c th nghim bi mt phng th nghim c ch nh so vi mt thit b dn chun tun theo cc yu cu trong 4.6.4.
Phng th nghim phi so snh cc c tnh k thut ca thit b c chng nhn vi cc ti liu m t k thut km theo. Trong trng hp c s tng thch, phng th nghim s tin hnh ba th nghim so snh ph hp vi 11.3.2 cho mi b thit b c chng nhn. Mi mt th nghim s dng mt loi xi mng khc nhau trong ba loi xi mng c mc khc nhau c la chn cho mc ch ny.
Trong trng hp cc kt qu ca tng th nghim trong ba th nghim so snh p ng cc yu cu trong 11.3.2.3, thit b ln cht thay th c coi l chp nhn c.
Sau chng nhn, m t k thut ca thit b v qui trnh ln cht thay th c coi l trng hp thay th c chng nhn cho 4.6.4 v 7.2, tng ng. Cc kt qu th nghim chng nhn c a vo h s v c lu gi trong sut thi gian thit b c s dng.
CH THCH: M t k thut ca thit b thay th v m t cc qui trnh ln cht thay th c chng nhn Ph lc A.
11.3.2 Phng php th nghim thit b ln cht thay th
11.3.2.1 Cch tin hnh
Chun b 20 cp m va s dng mt trong cc loi xi mng c la chn (xem 11.3.1) v ct chun ISO. Chun b hai m va trong mi cp theo th t ngu nhin, m n k tip ngay sau m kia ph hp vi tiu chun ny.
Ln cht mu th bng mt b thit b ln cht thay th ang c chng nhn cho mt m v thit b dn chun (4.6.4) cho m kia. Sau khi ln cht, tip tc thc hin cc bc tip theo ph hp vi tiu chun ny.
Th cng nn cc mu lng tr tui 28 d v ghi li tt c cc kt qu ring bit.
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11.3.2.2 Tnh ton v biu th kt qu
i vi mi cp m va, tnh ton v biu th kt qu cng nn ph hp vi 10.2.1 v bo co chng ph hp vi 10.2.2, ly x ch cho cc kt qu thu c vi b thit b ln cht thay th ang c chng nhn v y cho cc kt qu thu c vi thit b dn chun.
Tnh ton h s bin thin i vi tng b ca hai b kt qu v kim tra xem chng c tho mn ch tiu lp li ngn hn quy nh trong 10.2.3.1.
Nu hai b kt qu khng p ng yu cu ny, tip tc lm nh sau:
a) tnh gi tr trung bnh ca 20 kt qu, x v y ;
b) tnh lch chun ca 20 kt qu, s ; c) tnh chnh lch s hc gia tng kt qu v gi tr trung bnh, b qua du; d) trong trng hp mt trong cc chnh lch ny ln hn 3 s , loi b kt qu tng ng v tnh gi tr trung bnh ca 19 kt qu cn li; trong trng hp c hai hoc nhiu hn trong s cc chnh lch ny ln hn 3 s , loi b kt qu v lp li ton b qui trnh th; trong trng hp khng c chnh lch no ln hn 3 s , ly c 20 kt qu.
Tnh ton tiu chun chng nhn, D, biu th bng %, s dng Cng thc (4):
( ) 100=y
yxD (4)
trong :
x l gi tr trung bnh ca cc kt qu thu c vi thit b ln cht thay th c chng nhn, tnh bng megapascal (MPa);
y l gi tr trung bnh ca cc kt qu thu c vi thit b dn chun, tnh bng
megapascal (MPa). Bo co D ly chnh xc n 0,1 %, b qua du.
11.3.2.3 Yu cu
Ba gi tr tiu chun chng nhn, D, c tnh ton v biu th ph hp vi 11.3.2.2, mi gi tr tng ng vi mt trong ba loi xi mng c la chn v mt trong ba b thit b c la chn ang c chng nhn, phi nh hn 5,0 %. Trong trng hp c mt hoc nhiu hn cc gi tr D tnh ton c bng hoc ln hn 5,0 %, thit b ln cht thay th khng c chng nhn.
11.3.3 Bo co
Nh sn xut thit b ln cht thay th phi lm sn cho ngi mua mt bo co chi tit khi c yu cu gm:
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a) ngy sn xut; b) tn v a ch ca nh ng k sn xut; c) ngy chng nhn thit b ln cht thay th; d) tn v a ch ng k ca phng th nghim c ch nh; e) xc nhn cc kt qu th nghim ch ra rng thit b ln cht thay th tun theo cc yu cu ca tiu chun ny.
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Ph lc A
(Quy nh)
Thit b v cc qui trnh ln cht kiu rung thay th c chng nhn tng ng vi thit b v qui trnh ln cht kiu dn
A.1 Khi qut
Thit b dn chun c quy nh trong 4.6.4. Tuy nhin, thit b v cc qui trnh thay th khc c th c s dng ... vi iu kin chng c chng nhn tho mn cc iu khon trong tiu chun ny.
thc hin mc ch , mt qui trnh c quy nh trong iu 11 thc hin chng nhn thay th cho qui trnh chun. Cc chng trnh th nghim chng nhn v cc qui trnh ln cht c thc hin trn cc bn rung c th nh bn rung kiu A v B trong iu A.2 v A.3. Do vy, chng l cc v d v thit b ln cht thay th c chng nhn.
Ph hp vi 11.3.1, mi m t k thut (xem A.2.1 v A.3.1) c coi l trng hp thay th c chng nhn cho 4.6.4 v m t k thut ca qui trnh ln cht (xem A.2.2 v A.3.2) c coi l trng hp thay th c chng nhn cho 7.2.
A.2 Bn rung A
A. 2.1 M t k thut
Bn rung A c th c s dng nh mt thit b ln cht thay th, c cc c tnh k thut sau: a) Nguyn tc hot ng: b to rung in t vi dao ng danh ngha dng hnh sin. b) Ngun in in p: 230/240 V;
pha: mt pha;
dng in: ln nht 6,3 A;
tn s: danh ngha 50 Hz.
c) Khi lng rung (gm khun rng, phu v kp nhng khng bao gm b to rung): (35,0 1,5) kg. d) Bin dao ng thng ng o ti tm ca cc thnh ring bit v gc bn ngoi khun rng: (0,75 0,05) mm.
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Gia tc o ti tm ca cc thnh ring bit v cc gc bn ngoi khun rng c th l mt c tnh k thut thay th cho m t vn hnh rung ca bn A. Gi tr (26,0 3,0) m/s2 l tng ng vi gi tr a ra trong A.2.1 d). CH THCH: Bn rung c thit k ch to ra cc dao ng theo phng thng ng. Bin thng ng ca dao ng c hin th lin tc.
e) Tn s thc ca khi lng rung: (53,00 0,25) Hz. f) Tm rung: Tm vi b mt lm vic c mi nhn v c kch thc danh ngha ti thiu 400 mm x 300 mm gm mt trong
mt lp n bng thp cng, khng g vi cc g chu lc, hoc
mt lp kp bng kim loi cng (chiu dy ti thiu 20 mm), lp trn c lm bng thp khng g c chiu dy ti thiu 2 mm, gn cht vi lp di bng ma st v khp ci.
Nn nh du trng tm khi lng rung (gm kp nhng khng bao gm khun rng v phu) trn b mt lm vic ca tm rung, nm giao im ca hai trc thng ng trc giao.
g) Cc cht nh v: ba cht nh v c th iu chnh c cho php khun in y c nh v trn tm rung sao cho trng tm ca n trng vi trng tm ca khi lng rung do c nh du trn b mt lm vic ca tm rung.
h) Kp cho khun: g lp c nh thch hp cho khun 40 mm x 40 mm x 160 mm v c phu. i) Khi lng bn rung: ln hn 100 kg. Trong trng hp bn rung c lp t trong phng th nghim, nn b phn rung ng in t gn c nh vi mt mng b tng c khi lng t nht 200 kg, t trn mt lp vt liu cch rung, hn ch ti thiu s truyn chn ng sang thit b khc.
j) B gim rung: gm cc l xo bng cao su c t gia tm rung v khung c cc thng s k thut:
cng Shore: 45,
tc n hi: 145 MPa,
kch thc: ng knh 50 mm, chiu cao 45 mm.
k) Thng bng ca bn rung: cc vt iu chnh c (xem Hnh A.1) gn lin vo mt di bn chnh mt lm vic ca tm rung sao cho khng lch theo phng nm ngang qu 1 mm/m.
l) B hn gi t ng: c kh nng t ti 120 s v o chnh xc n 1 s.
A.2.2 Qui trnh ln cht s dng bn rung A
c mu th ngay sau khi chun b xong va.
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Lp khun v phu cht vo tm bn rung. t ch t ng tt bn rung sau khi ht thi gian rung l (120 1) s. Bt ngun bn rung, sau cho va y vo cc ngn khun theo hai lp trong khong thi gian ti a 45 s, theo cc bc nh sau.
a) Dng mt xng nh thch hp cho lp va u tin vo cc ngn khun, cho ngn ny xong mi chuyn sang ngn khc, trong vng 15 s, ti khong na chiu su ca ngn khun.
b) Sau khong 15 s , cho tip lp va th hai, cng cch thc nh lp va u tin trong vng 15 s tip. Cho ht ton b s lng va.
c) Khi bn rung tt thi gian (120 1) s, nhc khun nh nhng ra khi bn rung v tho phu ra.
Sau thc hin cc qui trnh gt, lau va tha v ghi nhn theo quy nh trong 7.2.
CH DN:
1 Phu
2 Khun 3 Kp 4 Tm rung 5 Bng iu khin c hin th bin , chnh nh bin , cng tc ngun v hn gi. 6 Cc vt iu chnh
Hnh A.1 S bn rung in hnh, kiu A
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A.3 Bn rung B
A.3.1 M t k thut
Bn rung B (xem Hnh A.2) c th c s dng nh thit b ln cht thay th c cc c tnh k thut sau:
a) Nguyn tc hot ng: b to rung in t vi dao ng danh ngha dng hnh sin. b) Ngun in in p: 230/240 V;
pha: mt pha;
dng in: xp x 6,3 A;
tn s: danh ngha 50 Hz.
c) Khi lng rung (gm khun rng v phu khng bao gm b to rung): (43,0 2,0) kg. d) Gia tc theo phng thng ng c o ti tm ngn gia khun: (4,50 0,25) g rms. CH THCH: Gia tc cc i theo cc phng ngang l 0,5 g rms.
e) Tn s thc ca khi lng rung: (55,50 0,25) Hz. f) Tm rung: Tm vi b mt lm vic c mi nhn v c kch thc danh ngha ti thiu 630 mm x 250 mm gm
mt lp n bng thp nh, cng c chiu dy (13 2) mm, v cc g chu lc v tm chuyn ng.
g) Kp khun: cc kp xoay thch hp i vi khun 40 mm x 40 mm x 160 mm v phu. h) Thng bng ca bn rung: bn rung phi c gn c nh trn nn nh v ly thng bng sao cho b mt lm vic ca tm rung khng lch theo phng nm ngang qu 1 mm/m.
i) B hn gi t ng: c kh nng t ti 120 s v o chnh xc n 1 s.
A.3.2 Qui trnh ln cht s dng bn rung B
Chun bn rung nm ngang v v sinh sch s. Chun b v lp gip khun ph hp vi 4.6.3. m bo mt di y khun phng v sch. Kp cht khun v phu vo bn rung v t bn rung lm vic vi gia tc (4,50 0,25) g rms.
c mu th ngay sau khi chun b xong va. Khi s dng b hn gi t ng, t ch t ng tt bn rung sau khi ht thi gian rung l (120 1) s. Bt ngun bn rung, sau cho ngay va vo cc ngn khun, hon thnh qui trnh di y trong khong thi gian ti a 45 s.
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a) Dng mt xng nh thch hp cho lp va u tin vo cc ngn khun trong vng 15 s, ti khong na chiu su cc ngn khun.
b) Khng tt bn rung, sau khi dng cho lp va u tin vo cc ngn khun trong vng 15 s, cho thm lp va th hai vo trong vng 15 s tip, trong cng tin trnh. c mu hi y hn khun.
c) Sau thi gian rung l (120 1) s, tt bn rung theo ch t ng hoc th cng. d) Nhc khun ra khi bn rung v tho phu ra. Sau thc hin cc qui trnh gt, lau va tha v ghi nhn theo quy nh trong 7.2.
CH DN:
1 Tm rung 2 Phu
3 Kp xoay 4 Khun 5 B gim rung 6 B to rung in t 7 Bng iu khin
Hnh A.2 S bn rung in hnh, kiu B
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Th mc ti liu tham kho
[1] TCVN 2330: 2007 (ISO 565: 1990), Sng th nghim - li kim loi t l v li t l bng in Kch thc l danh ngha.
[2] TCVN ISO/IEC 17025, Yu cu chung v nng lc ca cc phng th nghim v hiu chun.
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