Titanium Pipe Fittings: Qhov cuam tshuam ntawm cov ntsiab lus siab Hydrogen & Kev ceev faj tseem ceeb

Titanium yog cov tshuaj lom neeg heev thiab nquag ua rau hydrogen nqus thaum ua, kho cua sov, vuam, pickling thiab lwm yam txheej txheem. Cov ntsiab lus hydrogen ntau dhau tuaj yeem ua rau hydrogen embrittlement, hydrogen-induced cracking thiab kev ua haujlwm degradation, ua rau muaj kev cuam tshuam loj rau kev pabcuam kev nyab xeeb ntawmtitanium yeeb nkab fittings.

 

 

1.1 Cov ntawv uas muaj Hydrogen

Hydrogen atoms dissolve interstitially nyob rau hauv lub crystal lattices ntawm -Ti los yog -Ti, nrog tsawg solubility nyob rau hauv qis kub.

Thaum cov ntsiab lus hydrogen tshaj qhov kev txwv tsis pub solubility lossis qhov kub thiab txias, cov theem nkig xws li TiH₂ thiab TiH₁₋₂ raug tsim, nag lossis daus hauv cov duab acicular, flaky lossis loj heev, thiab feem ntau yog faib rau ntawm thaj tsam nplej, kev tsis sib haum xeeb thiab kev ntxhov siab.

 

1.2 Kev Txiav Txim Siab rau Cov Ntsiab Lus Ntau Tshaj Hydrogen

Lub teb chaws cov qauv, ASTM B338 thiab lwm yam kev qhia tshwj xeeb qhia tias cov ntsiab lus hydrogen hauv titanium thiab titanium alloy yeeb nkab fittings yuav tsum tsawg dua lossis sib npaug li 0.015% (150 ppm).

100 ppm: Kev cuam tshuam toughness txo qis.

300-500 ppm: Plasticity deteriorates sharply nrog hydride nag lossis daus loj heev.

0.05%.

 

2.1 Hydrogen Embrittlement

Lub siab -hardness acicular TiH₂ yog incompatible nrog lub matrix zog, yooj yim ua rau microcracks.

Kev ntxhov siab ua rau cov hydrogen mus rau hauv siab - thaj chaw muaj kev ntxhov siab, ua kom cov dej nag nrawm nrawm thiab nthuav tawm mus rau hauv cov kab nrib pleb.

Fracture yog ncua sijhawm thiab ua rau muaj kev puas tsuaj tam sim ntawd hauv kev pabcuam nrog muaj zog zais.

 

2.2 Nthuav Deterioration ntawm Mechanical Properties

Toughness poob ntau heev, thiab brittleness ua ntau pronounced nyob rau hauv qis kub.

Plasticity deteriorates, ua dabtsi yog khoov, flattening thiab lwm yam kev khiav hauj lwm yuav tsum tau tawg.

Hydrides ua raws li qhov chaw qaug zog, txo qhov qaug zog lub neej.

 

2.3 Cov xwm txheej siab ntawm vuam tsis xws luag

Hydrogen nyob rau hauv lub molten pas dej ua ke tsis khiav nyob rau hauv lub sij hawm thaum txias, tsim hydrogen pores.

Hydrides tsim cov kab nrib pleb txias hauv qhov kev ntxhov siab welding.

Cov tawv tawv ntawm cov welds thiab cua sov- cov cheeb tsam cuam tshuam txo qis, ua rau kev ua haujlwm tsis sib xws.

 

2.4 Deterioration ntawm Corrosion Resistance

Deg hydrides zoo li spall, accelerating corrosion.

Hydrogen embrittlement cracks ua raws li nruab nrab raws, yooj yim ua rau kev nyuaj siab corrosion cracking.

Hydrogen absorption thiab corrosion txhawb ib leeg ntawm lub zos tsis xws luag, accelerating tsis ua hauj lwm.

 

 

Hydrogen nqus ntawm titanium nrawm dua 400 degree; Kev nqus hydrogen loj heev tshwm sim tau yooj yim yog tias lub qhov cub muaj dej vapor, hydrogen los yog qhov chaw txo qis.

 

Impure argon, siab hydrogen cov ntsiab lus nyob rau hauv lub hauv paus hlau / vuam hlau, tsis txaus shielding, thiab ya raws nkag mus rau hauv lub molten pas dej ua ke tsim hydrogen.

Acid reacts nrog titanium los tsim cov hydrogen nquag thaum pickling; Cov concentration ntau dhau, kub thiab lub sijhawm yuav ua rau muaj kev nqus hydrogen ntau ntxiv.

 

Kev puas tsuaj rau cov yeeb yaj kiab oxide nto thiab tsim cov chaw ua haujlwm tshiab ua cov channel rau hydrogen absorption.

Cov ntsiab lus hydrogen ntau dhau hauv cov ntaub ntawv raw lawv tus kheej, thiab cov dej noo ntawm qhov chaw decomposes los tsim hydrogen ntawm qhov kub thiab txias hauv qhov chaw ntub dej.

 

4.1 Qhov Chaw Tswj

Xaiv cov titanium raj blanks nrog cov ntsiab lus hydrogen tsawg dua lossis sib npaug li 100 ppm ua cov khoom siv raw, ua qhov yuav tsum tau tshuaj xyuas thaum tuaj txog ntawm lub Hoobkas, thiab tsis lees paub cov khoom tsis yog- ua raws.

 

Tswj rhiav cov av noo tsawg dua lossis sib npaug li 60%, khaws cov khoom ua haujlwm kom qhuav, thiab txwv tsis pub ua dej los yog roj paug.

Ua tib zoo tshem tawm cov roj, av thiab xeb ua ntej vuam, thiab tsis txhob muaj kab mob los ntawm kev sib cuag nrog hlau.

 

4.2 Tus Txheej Txheem Tswj Thaum Ua Haujlwm

Kev kho cua sov

Ua ntej lub tshuab nqus tsev lossis siab -purity argon shielding annealing, nrog argon dew point < -40℃.

Pom zoo dehydrogenation kub: 538-760 degree; zam oxidation saum 760 degree; txwv tsis pub txo cua sov thiab txo lub sijhawm cua sov.

 

Vuam

Siv siab -purity argon Ntau dua los yog sib npaug rau 99.99%, nrog dew point < -40℃.

Ntxuav thiab qhuav grooves ua ntej welding, txais yuav tsawg tam sim no thiab siab vuam ceev, thiab muab tag nrho shielding rau ob sab pem hauv ntej thiab nraub qaum kom txog thaum txias hauv qab 200 degree.

Txais yuav tsawg- hydrogen txuam vuam hlau.

 

Pickling

Txais yuav qis-concentration HF + HNO₃ system, kub tsawg dua los yog sib npaug rau 40 degree, ntev 1-3 feeb.

Qhuav thiab qhuav tom qab pickling; txwv tsis pub pickling nrog ib qho kua qaub xws li hydrochloric acid lossis sulfuric acid.

 

Mechanical processing

Siv cov cuab yeej txiav tshwj xeeb thiab sib xyaw cov kua txiav kom tsis txhob muaj kev sib txhuam kub nce.

Txo cov cuab yeej cim thiab sib tsoo ntau dhau los tiv thaiv cov oxide zaj duab xis.

 

4.3 Kev ntsuas kho rau ntau dhau Hydrogen: Nqus Dehydrogenation Annealing

Ua lub tshuab nqus tsev dehydrogenation thaum cov ntsiab lus hydrogen> 150 ppm:

Kub: 580-650 degree

Vacuum degree: Tsawg dua lossis sib npaug rau 0.066 Pa

Lub sijhawm ua haujlwm: 2-4 teev

Txias hauv qhov cub kom qis dua 200℃ua ntej tso tawm

 

4.4 Kev soj ntsuam zoo

Tshawb xyuas cov ntsiab lus hydrogen los ntawm cov roj inert fusion-cov txheej txheem thermal conductivity kom ntseeg tau tias tsawg dua lossis sib npaug li 150 ppm.

Tshawb xyuas cov khoom siv kho tshuab xws li cuam tshuam toughness, elongation thiab flattening kev ua tau zoo.

Ua UT thiab PT uas tsis yog- kev sim ua kom puas tsuaj ntawm qhov tseem ceeb kom pom cov hydrogen- ua rau tawg.

 

 

Ruihang muab siab - zoo titanium thiab titanium alloy khoom. Peb cov txheej txheem tsim khoom nruj kom ntseeg tau tias peb ua tau raws li peb cov neeg siv khoom xav tau.Yog xav paub ntxiv, thov hu rau peb ntawm email:Sam.Rui@bjrh-titanium.com