Pipe Cutting Beveling Guide - Methods & Standards

Kev npaj cov yeeb nkab kawg - kev txiav, beveling, thiab ntxuav cov yeeb nkab kawg ua ntej vuam - yog ib qho tseem ceeb tshaj plaws uas txiav txim siab qhov vuam zoo hauv cov kav dej. Kev npaj kawg kom zoo ua kom tag nrho nkag mus, txaus fusion, thiab suab weld hlau deposition. Kev npaj tsis zoo kawg yog qhov ua rau muaj qhov tsis xws luag xws li tsis muaj kev nkag mus (qhov twg cov hlau tsis tuaj yeem ncav cuag lub hauv paus), fusion tsis tiav (qhov twg cov hlau tsis tuaj yeem txuas nrog cov yeeb nkab phab ntsa), porosity (gas daig hauv weld), thiab slag inclusions. Cov kev tsis zoo no tuaj yeem ua rau lub sijhawm ntxov weld tsis ua haujlwm nyob rau hauv siab los yog cyclic loading.

Cov qauv kev lag luam tsim cov kev cai tshwj xeeb rau kev npaj kawg. ASME B31.3 (Cov Txheej Txheem Piping) xav kom cov vuam xaus yuav tsum tau npaj rau cov geometry uas tau teev tseg hauv ASME B16.25 (Buttwelding Ends). AWS D10.12 (Pipe Vuam) muab kev taw qhia ntawm bevel kaum sab xis, lub hauv paus ntsej muag, thiab kev sib dhos sab hauv. Cov qauv no qhia meej tias lub kaum sab xis yuav tsum yog 30-37.5 degrees, nrog lub hauv paus ntsej muag (av) ntawm 1.6 hli (1/16 nti) rau feem ntau phab ntsa thicknesses. Qhov chaw sab hauv thiab sab nraud uas nyob ib sab ntawm lub bevel yuav tsum huv si thiab tsis muaj qhov tsis xws luag uas tuaj yeem cuam tshuam qhov zoo ntawm vuam.

Oxy-Kev txiav roj:Txoj kev pheej yig tshaj plaws rau cov pa roj carbon steel, oxy- roj txiav siv cov tshuaj tiv thaiv tshuaj tiv thaiv ntawm oxygen thiab cov hlau los txiav. Nws yog tsim rau phab ntsa thicknesses ntawm 3 hli mus rau 300 hli thiab yog dav siv nyob rau hauv teb fabrication. Qhov kev txiav saum npoo zoo yog nruab nrab, yuav tsum tau sib tsoo tom ntej lossis machining rau kev npaj vuam. Oxy- roj tsis haum rau cov hlau tsis muaj steel vim yog tsim ntawm refractory chromium oxides.
Plasma Txiav:Siv lub siab - dav hlau nrawm ntawm cov roj ionized (plasma) los txiav cov khoom siv hluav taws xob. Plasma txiav yog nrawm dua li oxy- roj thiab tuaj yeem txiav stainless hlau, txhuas, thiab lwm yam khoom tsis yog-ferrous. Kev txiav zoo yog qhov zoo, nrog rau qhov nqaim cua sov- thaj chaw cuam tshuam (HAZ). Niaj hnub nimno plasma systems nrog CNC tswj ua tiav kev txiav txim siab ntawm ± 1 hli. Plasma yog nyiam rau stainless hlau yeeb nkab txiav.
Band Saw Txiav:Txoj kev txias -txiav txoj kev uas ua rau qhov kawg ntawm qhov zoo tshaj plaws yam tsis muaj thermal distortion. Band saws yog zoo tagnrho rau precision txiav- mus rau- ntev ua haujlwm qhov twg square xaus thiab tsawg kawg burr yuav tsum tau. Cov kev txwv tseem ceeb yog txiav ceev (qis dua li cov txheej txheem thermal) thiab cov nqi hniav rau cov ntaub ntawv nyuaj xws li hlau alloy. Band saw txiav yog nyiam dua rau nyias -phab ntsa thiab precision yeeb nkab.
Laser txiav:Muab qhov siab tshaj plaws precision thiab nqaim tshaj plaws ntawm txhua txoj kev txiav. Laser txiav ua tiav qhov siab ntawm ± 0.1 hli thiab ua rau ze rau -burr- dawb ntug. Nws yog qhov zoo tagnrho rau nyias - cov yeeb nkab phab ntsa (txog 12 hli raug) thiab me me - txoj kab uas hla precision txiav. Cov cuab yeej siv siab siab txwv txiav laser txiav rau cov ntawv tshwj xeeb.

Txoj kev	Precision	Ceev	Nqi	Khoom siv	HAZ
Oxy- Roj	± 3 hli	Nruab nrab	Tsawg	CS nkaus xwb	Loj
Plasma	± 1 hli	Siab	Nruab nrab	Txhua yam hlau	Nruab nrab
Band Saw	± 0.5 hli	Tsawg	Nruab nrab	Txhua yam hlau	Tsis muaj
Laser	± 0.1 hli	Siab	Siab	Nyias- cov hlau phab ntsa	Tsawg kawg

Standard V-Bevel:Qhov feem ntau bevel geometry, nrog lub kaum sab xis ntawm 30-37.5 degrees thiab lub hauv paus ntsej muag ntawm 1.6 hli. V-bevel muab kev nkag tau zoo rau vuam thaum tuav lub hauv paus txaus kom tiv thaiv kev kub hnyiab. Nws yog tsim rau phab ntsa thickness ntawm 3 hli mus rau 20 hli. Lub kaum sab xis suav nrog (tag nrho lub kaum sab xis ntawm ob qhov chaw beveled thaum ob lub kav dej sib haum) feem ntau yog 60-75 degrees.
Compound Bevel / J-Bevel:Siv rau tuab- cov yeeb nkab phab ntsa (25 hli thiab siab dua), qhov twg tus qauv V-bevel yuav xav tau ntau qhov vuam hlau ntim. Qhov sib xyaw bevel muaj tus qauv V-bevel ntawm sab nraud thiab lub kaum sab xis (10-20 degrees) lossis J-zoo li tus contour ze ntawm lub hauv paus. Qhov no txo cov weld ntim thaum tswj kev nkag tau hauv paus txaus. J-bevels feem ntau yog ua los ntawm cov khoom tshwj xeeb beveling.
U-Bevel:AJ-bevel siv rau ob sab ntawm qhov sib koom ua ke, tsim kom muaj U-zoo li tus ntoo khaub lig-section. U-bevels tau teev tseg rau ntxiv- tuab- cov yeeb nkab phab ntsa (50 mm thiab siab dua) thiab rau cov yeeb nkab steel hlau uas txo qhov ntim qhov ntim tsawg kawg PWHT lub sijhawm. Lub U-bevel yuav tsum tau precision machining thiab feem ntau yog tsim nyob rau hauv lub Hoobkas es tsis yog nyob rau hauv lub teb.
Square Butt / I-Bevel:Tsis muaj lub kaum sab xis, tsuas yog siv rau nyias - cov yeeb nkab phab ntsa (txog 3 hli / SCH 10 thiab sib dua). Lub pob tw pob ob sab tso siab rau kev nkag mus los ntawm ib qho kev sib txuas thiab yuav tsum tau ua kom haum zoo -txog nrog xoom qhov sib txawv. Nws yog feem ntau siv hauv cov kav dej tsis huv stainless hlau rau cov khoom noj thiab tshuaj siv.

Handheld beveling machines (tseem hu ua cov cuab yeej beveling lossis cov cuab yeej siv vuam kawg) yog cov khoom siv nqa tau tuaj yeem nqa mus rau cov yeeb nkab hauv thaj chaw lossis kev cob qhia. Lawv feem ntau siv lub taub hau tig uas hla cov yeeb nkab kawg los tsim lub kaum sab xis zoo ib yam. Cov tshuab beveling nyob ruaj ruaj yog lub Hoobkas- cov cuab yeej teeb tsa uas txheej txheem yeeb nkab xaus rau hauv cov kab ntau lawm, muab cov khoom siv ntau dua thiab qhov tseeb. Tsis siv neeg cov yeeb nkab bevelers tshwj xeeb rau cov yeeb nkab loj - txoj kab uas hla thiab tuaj yeem bevel, ntsej muag, thiab counterbore hauv ib qho kev teeb tsa. Oxy-roj beveling yog qee zaum siv rau kev ua haujlwm ntxhib tab sis ua rau qhov chaw uas yuav tsum tau sib tsoo ua ntej vuam vim qhov ntxhib tiav thiab hardened HAZ.

Plain End (PE):Cov yeeb nkab kawg yog txiav square tsis muaj bevel. Siv rau kev sib txuas ntawm lub qhov (socket weld), kev sib txuas ntawm threaded, thiab qhov twg cov yeeb nkab yog mechanically txuas nrog lub pob tw -welded.
Beveled End (BE):Cov yeeb nkab kawg yog beveled rau lub kaum sab xis (30-37.5 degrees) rau pob tw vuam. Qhov no yog tus qauv kawg npaj rau feem ntau cov txheej txheem thiab cov kav dej siv hluav taws xob ib qho ASME B16.25.
Threaded End (TE):Cov yeeb nkab kawg yog threaded rau NPT (National Yeeb Nkab Taper) lossis lwm cov qauv xov rau kev sib txuas ntawm cov tshuab threaded. Threaded xaus yog muaj nyob rau hauv me me (txog 2 ") rau qis - mus rau - kev siv siab nruab nrab.
Grooved End:Ib qhov zawj raug txiav ze ntawm cov yeeb nkab kawg rau cov khoom siv sib txuas (Victaulic-type). Grooved xaus ua kom nrawm nrawm nrawm yam tsis muaj vuam, feem ntau hauv kev tiv thaiv hluav taws thiab cov kav dej ib ntus.
Qhov (socket End):Cov yeeb nkab kawg tau nthuav dav lossis haum nrog lub qhov (socket) rau kev sib txuas ntawm qhov sib txuas ntawm ASME B16.11. Kev sib txuas ntawm qhov (socket weld) yog siv nyob rau hauv siab -siab me me- bore piping.

Cov yeeb nkab carbon steel txais txhua txoj kev txiav, nrog oxy- roj yog qhov kev lag luam tshaj plaws rau kev ua haujlwm. Stainless hlau yeeb nkab yuav tsum tau txiav txias los yog plasma / laser txoj kev vim oxy- roj tsis zoo (stainless hlau tsis txhawb cov tshuaj tiv thaiv oxidation). Tsis tas li ntawd, cov khoom siv hluav taws xob ntau dhau thaum txiav tuaj yeem ua rau muaj kev kub ntxhov ntawm austenitic stainless hlau (chromium carbide nag lossis daus ntawm cov ciam teb ntawm 425-870 degree), txo cov corrosion kuj. Yog hais tias thermal txiav yog siv rau stainless hlau, HAZ yuav tsum tau muab tshem tawm los ntawm kev sib tsoo los yog txiav ntug yuav tsum tau tov annealed. Alloy steel yeeb nkab (P11, P22, P91) yuav tsum tau preheat ua ntej txiav (feem ntau 150-200℃rau P11 / P22, 200-300℃rau P91) los tiv thaiv hardening thiab cracking nyob rau hauv lub HAZ.

Ua ntej vuam, cov yeeb nkab kawg yuav tsum tau muab ntxuav kom tshem tawm cov roj, roj, xeb, zeb nplai, thiab lwm yam kab mob. Cov txheej txheem ntxuav muaj xws li hnyav so, txhuam hlau, thiab sib tsoo. Qhov chaw ntxuav yuav tsum ncua tsawg kawg 25 mm los ntawm qhov sib koom ua ke. Tom qab ntxuav, qhov kawg qhov ntev yuav tsum tau txheeb xyuas: OD kam rau ua, phab ntsa thickness, bevel kaum sab xis (feem ntau ntsuas nrog ib tug bevel protractor), lub hauv paus lub ntsej muag dav (1.6 ± 0.8 mm), thiab sab hauv alignment kom haum -up.

ManufacturerPipe muaj lub Hoobkas - theem ua ntej - cov kev pabcuam ua haujlwm uas txuag tau ntawm - lub sijhawm tsim khoom thiab ua kom zoo ib yam. Peb muab kev txiav - mus rau - ntev kev pabcuam nrog qhov tseeb ntawm ± 2 hli rau qhov ntev txog 12 meters. Peb batch beveling cov txheej txheem ntau cov kav dej ib txhij mus rau lub kaum sab xis ntawm ASME B16.25. Peb kuj siv cov khoom tiv thaiv kawg los tiv thaiv kev puas tsuaj thaum thauj. Kev ua tiav kev cai, suav nrog ob lub bevels thiab cov ces kaum tshwj xeeb, muaj rau qhov project -cov kev cai tshwj xeeb.

Hu rau peb pab neeg kom txiav-rau-ntev, beveling, thiab xaus kev pab npaj rau koj qhov project piping.

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