Yuav ua li cas xaiv 316 Stainless Hlau Sheath Phab Ntsa Thickness cuam tshuam qhov kev pheej hmoo ntawm kev nyuaj siab Corrosion Cracking nyob rau hauv kub Chloride ib puag ncig siab tshaj 60 Degrees Celsius?

Nyob rau hauv cov ntaub ntawv ntawm chemical plant engineers thiab cov neeg ua hauj lwm saib xyuas hais txog hluav taws xob immersion heaters rau daim ntawv thov uas muaj cov tshuaj chloride kub xws li seawater -cooled heat exchangers, brine concentration tanks, thiab tej yam khoom noj khoom haus, kev nyuaj siab corrosion cracking yog ib tug cais tsis ua hauj lwm hom ntawm pitting los yog crevice corrosion. Tsis zoo li homogeneous phab ntsa thinning, kev nyuaj siab corrosion cracking tshwm sim nyob rau hauv branched transgranular los yog intergranular kab nrib pleb uas yuav tho tau ib tug 316 stainless hlau sheath nyob rau hauv lub lis piam los yog hli, feem ntau nrog me ntsis kev ceeb toom. Kev sib cuam tshuam ntawm cov ntawv thov lossis qhov seem tensile kev ntxhov siab, chloride concentration, qhov kub thiab txias ntawm phab ntsa txiav txim siab yog tias cov sheath tshwj xeeb yuav nyob mus ib txhis los yog ua tsis tau zoo. Tsab ntawv xov xwm no qhia txog qhov cuam tshuam ntawm phab ntsa thickness ntawm qhov kev pheej hmoo ntawm kev ntxhov siab corrosion tawg los ntawm nws cov nyhuv ntawm qhov loj ntawm qhov seem ntawm kev ntxhov siab los ntawm kev tsim khoom thiab lub sij hawm tsim nyog rau kev tawg mus rau hauv phab ntsa.

Peb Qhov Tseem Ceeb Rau Kev Nyuaj Siab Corrosion Cracking hauv 316 Sheaths
Kev ntxhov siab corrosion tawg ntawm austenitic stainless hlau xws li 316 yuav tsum muaj peb lub sijhawm ib txhij tshwm sim, cov khoom raug cuam tshuam, qib tseem ceeb ntawm tensile kev nyuaj siab thiab ib puag ncig corrosive uas muaj chlorides, ntawm qhov kub thiab txias feem ntau siab tshaj 60℃. 316 yog qhov tsis tshua muaj kev tawm tsam tshaj 304 tab sis tsis tiv thaiv kab mob. Tensile stresses tuaj yeem siv rau sab nraud los ntawm lub zog siab lossis thermal expansion lossis tuaj yeem yog cov kev ntxhov siab ntawm cov txheej txheem tsim khoom xws li khoov, swaging, thiab vuam ntawm cov ntaub. Kev ua haujlwm swaging siv los ua kom cov magnesium oxide rwb thaiv tsev nyob ib ncig ntawm cov hlau tsis muaj zog hauv cov cua sov sheaths imposes loj residual circumferential tensile stresses rau sab nraud ntawm lub 316 raj. Cov kev ntxhov siab seem no tuaj yeem siab npaum li qhov muaj zog ntawm cov khoom siv thiab yog qhov tseem ceeb rau kev pib tawg ntawm cov kev ntxhov siab tsawg. Qhov kev nthuav tawm ntawm kev ntxhov siab corrosion tawg ntawm lub qhov los yog qhov chaw tsis zoo tom qab pib yog 0.1-10 millimeters ib hlis nyob ntawm cov ntsiab lus chloride thiab kub. Cov kab nrib pleb tawm mus txog thaum cov phab ntsa seem tsis txaus los tuav lub siab hauv lossis qhov tawg nkag mus rau sab hauv phab ntsa uas ua rau ingress ntawm cov txheej txheem dej thiab hluav taws xob tsis ua haujlwm.

Kev cuam tshuam ntawm phab ntsa thickness ntawm tawg pib thiab propagation
Phab ntsa thickness muaj ob qhov cuam tshuam rau kev pheej hmoo ntawm kev ntxhov siab corrosion cracking. Ua ntej, cov phab ntsa nyias nyias yuav muaj kev ntxhov siab ntau dua rau tib lub zog txo qis vim tias qhov ua haujlwm txias txuas ntxiv mus rau hauv phab ntsa hla ntu. Lub 0.8 hli sheath tej zaum yuav muaj qhov seem residual stresses ntawm 400-500 MPa tom qab swaging tab sis ib tug 2.0 hli sheath ntawm zoo tib yam txheej sab nraud tej zaum yuav muaj tsuas yog 200-300 MPa residual kev ntxhov siab vim qhov txias ua hauj lwm nyhuv yog txwv rau ib tug ntiav nto txheej txheeb ze rau tag nrho cov thickness. Qhov siab dua residual kev nyuaj siab txo lub sij hawm rau tawg pib. Qhov thib ob, lub sij hawm rau perforation rau ib tug muab tawg propagation tus nqi yog ncaj qha proportional rau lub seem phab ntsa thickness ib zaug ib tug tawg pib . 4 hli mus tho ib tug 2.0 hli sheath, tsis tau ib tug tawg kis ntawm 0.5 hli / hli yuav permeate ib tug 0.8 hli sheath nyob rau hauv 1.6 lub hlis. Qhov cuam tshuam net yog qhov kev pheej hmoo uas tsis yog -monotonic. Cov tawv nqaij nyias nyias (<1.0 mm) develop cracks quickly yet have little material to penetrate. Very thick sheaths (above 2.0 mm) break more slowly, but take longer to perforate. Intermediate thicknesses 1.2–1.6 mm are the highest risk category, because they start at moderate rates, but have enough wall thickness to conceal developing cracks for a long time before abrupt failure.

316 Sheaths Kub thiab Chloride Concentration Thresholds
316 stainless steel is not susceptible to stress corrosion cracking in chloride solutions below 60°C. Cracking will only occur in concentrated chlorides >1,000 ppm thiab muaj zog tensile hom ntawm 60℃thiab 80 degree. Ntawm cov tshuaj chloride nruab nrab ntawm 100-500 ppm qhov kev pheej hmoo yuav ua rau hnyav ntawm 80℃thiab 120℃. 316 tsis haum rau ib puag ncig chloride nrog tensile stress, tsis hais phab ntsa thickness, ntawm qhov kub siab tshaj 120 degree. Nyob rau hauv cov kev pheej hmoo siab kub ntau yam uas siv cov cua sov sheaths, cov tswv yim engineering teb yog los txo cov chloride concentration kom qis dua 10 ppm, los yog tshem tawm tensile stresses los ntawm tag nrho cov annealing tom qab tsim, los yog hloov mus rau ib tug ntau resistant alloy xws li Incoloy 825 los yog titanium. Cov lus pom zoo rau phab ntsa tuab ntawm 316 sheaths hauv kev pabcuam chloride yog raws li hauv qab no, raws li qhov ntsuas kub thiab cov tshuaj chloride, piv txwv tias cov kab mob seem ntawm swaging tsis tuaj yeem tshem tawm:

Kev khiav hauj lwm kub Chloride Concentration pom zoo yam tsawg kawg nkaus 316 Sheath Phab ntsa Thickness Cia siab rau kev pab cuam lub neej ua ntej muaj kev pheej hmoo ntawm kev nyuaj siab Corrosion Cracking lwm txoj kev pom zoo
60–80℃< 100 ppm 1.2 mm Tsawg kev pheej hmoo,> 5 xyoos 316 txais 60–80℃100–1,000 ppm 1.6 mm Muaj kev pheej hmoo, 2–4 xyoo Saib xyuas ib xyoos ib zaug 60–80 degree> 1,000 ppm 2.0 mm2 siab siab Consider,
80 - 100℃< 100 ppm 1.6 mm Muaj kev pheej hmoo siab, 2 - 3 xyoo kev hloov kho 80-100℃100-500 ppm 2.0 mm Cov kev pheej hmoo siab, 1-2 xyoo Pom zoo alloy kho dua tshiab .
80-100oC> 500ppm Tsis pom zoo Tsis pom zoo,<1 yearUse titanium or Incoloy 825;
100-120℃txhua qhov ntsuas tau ClNot pom zoo tsis ua hauj lwm nrawm yuav tsum tau hloov kho cov hlau 120℃Txhua yam tshuaj chloride tsis haumImminent tsis ua hauj lwm Hloov cov khoom specifications
Tsim cov kev hloov pauv kom txo qis kev ntxhov siab corrosion cracking kev pheej hmoo tsis ntxiv phab ntsa thickness
Cov kws tsim qauv yuav tsum xav txog peb qhov kev hloov kho uas txo qis qhov tensile kev nyuaj siab tivthaiv ntawm cov kev ntxhov siab corrosion cracking sib npaug ua ntej yuav txais cov nqi cua sov ntawm phab ntsa tuab. Thawj thiab qhov tseem ceeb tshaj plaws yog ib qho tag nrho ntawm lub tshuab ua kom sov ua tiav tom qab tag nrho cov txheej txheem swaging thiab khoov. Annealing ntawm 1050℃ua raws li kev ua kom txias sai yuav txo qhov seem seem los ntawm kwv yees li 80-90% nrog me ntsis cuam tshuam rau corrosion kuj. Kev lag luam tawm - tawm suav nrog lub peev xwm rau oxidation ntawm cov hlau tsis kam sab hauv thiab cov nqi tsim khoom ntxiv. Qhov kev hloov thib 2 yog qhov txhais ntawm qhov qis - seem - cov txheej txheem kev ntxhov siab. Ntau lub teeb swaging hla nrog cov kev ntxhov siab nruab nrab ntawm kev ntxhov siab ua rau tsawg dua cov kab mob seem ntau dua ib qho kev txo qis. Cov neeg tsim khoom ntawm cov khoom siv hluav taws xob muaj kev ntseeg siab feem ntau muaj peev xwm ua kom muaj qhov seem seem nyob hauv qab 150 MPa txawm nyob rau hauv 1.2 hli phab ntsa sheaths. Qhov kev hloov kho thib peb yog los tsim cov kab ke kom txo tau cov kev ntxhov siab tensile. Tsim kom muaj lub siab tsis zoo, hloov hluav taws xob sib txuas, thiab zam kev txhim kho tsis yooj yim uas tiv thaiv thermal expansion tag nrho ua haujlwm kom txo qis tag nrho tensile kev nyuaj siab ntawm lub hnab. Hauv qhov xwm txheej uas siv cov kev hloov kho no, lub 1.2 hli 316 sheath yuav muab kev pab cuam lub neej txaus nyob rau hauv cov xwm txheej uas yuav ua rau lub 2.0 hli sheath nrog siab residual stresses.

Cov tswv yim rau kev tshuaj xyuas thiab saib xyuas cov kev teeb tsa uas twb muaj lawm
Thaum lub tshuab cua sov ua haujlwm nyob rau hauv ib puag ncig kub chloride, kev xaiv phab ntsa thickness tsis tuaj yeem hloov kho retroactively. Hloov chaw, nquag tshuaj xyuas rau kev ntxhov siab corrosion cracking yog yuav tsum tau. Dye penetrant test ntawm sheath nto tuaj yeem ntes cov kab nrib pleb ua ntej lawv permeate phab ntsa. Rau 80 degree, 500 ppm chloride kev pabcuam, 1.2-1.6 hli phab ntsa thickness sheaths, kev tshuaj xyuas peb lub hlis twg yog qhia. Rau cov ntaub tuab tuab ntawm 2.0 hli thiab dhau mus, ib nrab- kev kuaj xyuas ib xyoos ib zaug tuaj yeem tsim nyog, vim tias lub sijhawm nthuav tawm ntau ntxiv yuav ceeb toom ntxiv. Kev soj ntsuam acoustic emissions tuaj yeem ntes cov kev ua txhaum ntawm lub sijhawm tiag tiag thaum lub sijhawm ua haujlwm, txawm hais tias txoj hauv kev no feem ntau yog siv rau qhov tseem ceeb lossis siab tshaj - cov khoom muaj nqis. Qhov taw qhia tseem ceeb ceeb toom yog kev txhim kho ntawm cov pob txha tawg zoo nyob rau saum npoo ntawm lub plhaub, feem ntau tsuas yog pom nyob rau hauv kev nthuav dav lossis nrog kev siv cov tshuaj pleev xim. Yog tias pom cov kab nrib pleb yuav tsum tau hloov pauv sai sai txawm tias cov phab ntsa tuab npaum li cas tseem tshuav vim tias qhov kev nthuav tawm tuaj yeem ua kom nrawm rau hauv txoj kev tsis tuaj yeem.

Xaus: Qhia Specification ntawm Phab Ntsa Thickness rau Stress Corrosion Cracking Control
Phab ntsa tuab tsis yog qhov ntsuas qhov ruaj khov, tab sis yog ib qho cuab yeej tswj kev pheej hmoo rau cov engineers xaiv 316 stainless hlau sheaths rau hluav taws xob immersion heaters nyob rau hauv high chloride ib puag ncig. Cov phab ntsa Thicker ncua sij hawm tawg tawg, tab sis tsis txhob tiv thaiv qhov tawg pib yog tias qhov seem seem loj. Cov phab ntsa nyias nyias tuaj yeem ua rau cov kab nrib pleb sai dua tab sis perforate sai dua, muab qhov zais zais tsawg dua. Txoj hauv kev zoo tshaj plaws kom tsis txhob muaj kev ntxhov siab corrosion yog kom tsis txhob muaj cov xwm txheej uas nws tuaj yeem tshwm sim - uas yog kom kub qis dua 60 o C, chlorides qis dua 100 ppm lossis cov kab mob seem hauv qab 100 MPa. Nyob rau hauv cov ntaub ntawv ntawm daim ntawv thov no tej yam kev mob yog inevitable, ces qhov zoo tshaj plaws kev sib haum xeeb ntawm tawg pib thiab tawg propagation margin yog muab los ntawm ib tug 1.6-2.0 hli phab ntsa thickness nrog tag nrho annealing. Yog tias cov tshuaj chloride ntau tshaj 1,000 ppm lossis yog tias qhov kub thiab txias tshaj 100 degree, tsuas yog cov lus qhia tsim nyog tsim nyog yog xaiv cov hlau sib txawv. Tus nqi ntawm kev kho dua tshiab rau Incoloy 825 lossis titanium yog qhov tsawg tshaj plaws piv nrog tus nqi ntawm lub tshuab cua sov uas tsis tau xav txog ua rau muaj kev sib kis ntawm cov khoom batch, poob ntawm cov txheej txheem los yog kev nyab xeeb los ntawm cov hluav taws xob nyob hauv kev sib cuag nrog cov tshuaj chloride.