430 vs 439 vs 444: Xaiv Txoj Cai Ferritic Stainless Hlau

 

Dab tsi yog cov ntsiab lus tseem ceeb uas paub qhov txawv ntawm peb qib no?
Txhua yam yog chromium-raws li, npib tsib xee- dawb ferritic steels.430yog lub hauv paus nrog ~ 17% Cr thiab tsis txhob txwm ua kom ruaj khov.439yog titanium-stabilized thiab muaj me ntsis Cr (~17-19%) los tiv thaiv rhiab heev thaum vuam.444muaj ob qho tib si titanium / niobium stabilization thiab ib qho tseem ceeb ntxiv ntawm 1.75-2.5% molybdenum, ho boosting nws tsis kam rau pitting thiab crevice corrosion. Qhov kev nce qib no ncaj qha dictates lawv cov nqi thiab kev ua haujlwm.

Qhov kev sib sau ua ke no txhais li cas rau qhov tiag -kev ua kom haum hauv ntiaj teb no?
430yog tsim rau qhuav sab hauv daim ntaub ntawv, hniav trim, thiab cov khoom interiors uas vuam tsis tas yuav tsum tau thiab corrosion raug tsawg heev.439yog lub workhorse rau automotive tso systems (welded), tshav kub exchangers, thiab daim ntaub ntawv uas muaj cua sov thiab condensation qhov twg weld kev ncaj ncees yog qhov tseem ceeb.444yog tsim los rau kev sib cuag nrog cov tshuaj chloride- muaj cov dej, ua rau nws tus qauv rau cov dej kub tank hauv ob sab phlu, hnub ci thermal systems, thiab architectural Cheebtsam nyob rau hauv ntug hiav txwv dej los yog de-icing ntsev ib puag ncig.

Dab tsi yog qhov tseem ceeb welding thiab fabrication txiav txim siab rau txhua qib?
430tsis zoo weldability rau kev siv corrosion; welding tuaj yeem ua rau rhiab heev thiab embrittlement.439muaj zoo weldability vim nws stabilization, ua rau nws haum rau fabricated sib dhos.444kuj muaj zoo weldability. Rau tag nrho cov qib ferritic, tswj cov khoom siv hluav taws xob kom txo qis kev loj hlob hauv cov cua sov- thaj tsam cuam tshuam yog qhov tseem ceeb. Formability yog feem ntau zoo, tab sis lub zog siab dua ntawm 444 yuav xav tau me ntsis ntxiv quab yuam.

Los ntawm tag nrho cov kev xav txog tus nqi, yuav ua li cas ib qhov project yuav ua kom pom tseeb qhov kev nce qib no?
Kev ncaj ncees yog nyob ntawm tus nqi ntawm lub neej thiab kev pheej hmoo ntawm kev ua tsis tiav. Siv430tsuas yog thaum tsis ua hauj lwm tsis muaj nqi ntxiv. Txhim kho rau439thaum welding yog koom tes los yog ib puag ncig muaj xws li me me corrosives (condensate, pa gases). Kev nqis peev hauv444thaum tsis ua hauj lwm yuav raug nqi, tsis muaj kev nyab xeeb, los yog ua rau lub sij hawm tseem ceeb, xws li lub tank dej kub los yog lub façade corroded. Tus nqi ntawm cov khoom siv ntxiv yog yuav luag ib txwm tsawg dua tus nqi ntawm ib qho tsis ua haujlwm.

Yuav ua li cas yog ib qho yooj yim, kev txiav txim siab- ua flowchart rau xaiv ntawm peb qib ferritic no?

Puas yuav welded?Yog tias TSIS TAU, thiab ib puag ncig qhuav / sab hauv tsev, xav txog 430. Yog tias YOG, tam sim ntawd tshem tawm 430.

Puas yuav muaj kev sib cuag nrog cov tshuaj chlorides (dej ntsev, de-icing ntsev)?Yog tsis yog, xaiv 439. Yog tias YOG, xaiv 444.

Puas yog daim ntawv thov lub nkoj dej kub?Yog tias YOG, xaiv 444.
Daim ntawv qhia kev khiav dej num no ua kom muaj kev tsim nyog ua ntej tus nqi raug txiav txim siab, tiv thaiv raws li - specification.