Galvanized steel kauj sawv raws li tus qauv thoob ntiaj teb rau cov nqi-zoo corrosion kuj nyob rau hauv kev tsim thiab kev tsim kho sectors. Los ntawm kev sib txuas cov zinc txheej tiv thaiv rau cov hlau substrate, cov khoom siv no muab kev tiv thaiv tseem ceeb rau cov ntsiab lus, ua kom muaj kev ncaj ncees ntawm cov hlau uas tsis kho cov hlau yuav ua tsis tiav. Txawm li cas los xij, tsuas yog xaiv 'galvanized steel' tsis tshua muaj txaus los lav kev ua tau zoo. Qhov kev sib tw tiag tiag yog nyob rau hauv kev taw qhia qhov sib txawv ntawm cov khoom siv hluav taws xob: thaum cov neeg yuav khoom feem ntau nkag siab tias zinc tiv thaiv xeb, ob peb tau nkag siab qhov cuam tshuam ntawm cov txheej txheem tshwj xeeb (xws li G60 piv rau G90) lossis cov txheej txheem sib txawv ntawm cov txheej txheem kub-dip thiab electro-galvanizing.
Ua tsis tau raws li cov kev qhia tshwj xeeb rau ib puag ncig uas xav tau feem ntau ua rau muaj kev puas tsuaj rau qhov kev tshwm sim, suav nrog kev txhim kho ntxov ntxov thiab kev ua haujlwm tsis muaj zog. Cov lus qhia no yog txhawm rau txuas qhov sib txawv los ntawm kev sib txuas cov kev siv tshwj xeeb hauv kev lag luam ncaj qha mus rau cov kev qhia tshwj xeeb uas xav tau kom ua tiav. Los ntawm kev nkag siab txog cov nuances ntawm txheej thickness, formability qauv, thiab ib puag ncig kev txwv, koj tuaj yeem ua kom cov khoom siv ntev thiab ua kom rov qab los ntawm kev nqis peev rau koj txoj kev tsim khoom lossis kev tsim kho.
Ntsiab Cai
Tus nqi tseem ceeb: Galvanized steel sib npaug ua ntej tus nqi nrog lub sijhawm ntev los ntawm kev tiv thaiv kev txi (zinc txi nws tus kheej rau cov hlau).
Sector Dominance: Qhov tseem ceeb hauv kev tsim kho (framing / vov tsev), tsheb (cov vaj huam sib luag), thiab kev ua liaj ua teb vim muaj kev tiv thaiv ib puag ncig.
Kev pheej hmoo ntawm kev xaiv: Siv qhov hnyav txheej txheej tsis raug (xws li, G60 nyob rau hauv qhov chaw siab-corrosion) ua rau ua tsis tiav ntxov; Cov ntug hiav txwv dej feem ntau xav tau lwm txoj hauv kev xws li Galvalume lossis Aluminium.
Cov Lus Qhia Txog Kev Muag Khoom: Kev xaiv cov khoom yuav tsum tau hais los ntawm ASTM A653 tus qauv thiab cov kev cai tshwj xeeb tsim (lock-forming vs. deep drawing).
Core Industrial Applications thiab Performance Requirements
Lub versatility ntawm Galvanized Steel Chev tso cai rau nws los ua tus txha nraub qaum rau ntau yam kev lag luam. Txawm li cas los xij, txhua qhov kev xav tau tshwj xeeb ntawm cov khoom siv kho tshuab thiab txheej txheej tshwj xeeb kom tiv taus nws qhov chaw ua haujlwm tshwj xeeb.
Kev Tsim Kho & Infrastructure (Tus Tsav Tsheb Loj)
Kev tsim kho suav rau qhov ntim loj tshaj plaws ntawm galvanized steel noj thoob ntiaj teb. Hauv qhov haujlwm no, cov khoom siv ua haujlwm rau ob qho haujlwm sib txawv: kev txhawb nqa thiab kev tiv thaiv ib puag ncig.
Daim Ntawv Thov: Rau Lub Teeb Gauge Steel Framing (LGS), purlins, thiab girts, qhov tseem ceeb yuav tsum yog lub zog tawm los. Cov neeg tsim khoom feem ntau cia siab rau Qib 33, 50, lossis 80 steel kom ntseeg tau tias lub pob txha ntawm lub tsev tuaj yeem txhawb nqa cov khoom tseem ceeb. Qhov tseem ceeb, cov khoom siv no siv G60 rau G90 txheej hnyav. Txij li thaum cov khoom no feem ntau nyob rau hauv cov phab ntsa lossis lub ru tsev, lawv raug tiv thaiv los ntawm cov nag ncaj qha tab sis yuav tsum tseem tiv thaiv cov av noo thiab condensation uas yuav cuam tshuam cov txheej txheem kev ncaj ncees lub sijhawm.
Lub tsev lub hnab ntawv: Cov ru tsev thiab cov vaj huam sib luag ntsib ncaj qha raug UV rays, los nag, thiab daus. Thaum feem ntau siv los ua lub substrate rau Pre-Painted Galvanized Iron (PPGI), cov txheej zinc hauv qab tseem tseem ceeb heev. Yog tias cov xim raug khawb, cov zinc muab ib qho kev tiv thaiv thib ob. Xaiv qhov zoo substrate nto yog qhov tseem ceeb ntawm no; ib tug du tiav kom zoo xim adhesion, tiv thaiv tev los yog blistering xyoo hauv kab.
Infrastructure: Kev loj guardrails, culverts, thiab choj Cheebtsam ua hauj lwm nyob rau hauv ib co ntawm qhov hnyav tshaj tej yam kev mob xav, ntsib txoj kev ntsev, khib nyiab, thiab tsis tu ncua noo noo. Cov ntawv thov no xav tau cov zinc txheej hnyav, feem ntau tshaj cov qib kev lag luam, los muab ntau xyoo ntawm kev saib xyuas tsis pub dawb. Cov kws ua haujlwm saib xyuas qhov tseem ceeb ntawm cov ntaub ntawv no vim tias kev hloov kho vaj tse yog qhov nyuaj thiab kim.
Automotive Manufacturing (Lub Precision Tsav Tsheb)
Kev lag luam automotive drives innovation nyob rau hauv galvanizing technology, thawb rau cov ntaub ntawv uas muaj siab zog-rau-hnyav piv txwv tsis pub rau corrosion kuj.
Cov Vaj Huam Sib Luag: Sab nrauv xws li fenders, hoods, thiab lub qhov rooj vaj huam sib luag yuav tsum tau ua kom zoo nkauj rau kev pleev xim. Ntawm no, manufacturers feem ntau siv 'Galvannealed' steel. Qhov kev hloov pauv no suav nrog kev kho cua sov tom qab uas hloov cov zinc txheej rau hauv zinc-hlau alloy. Qhov tshwm sim yog lub ntsej muag matte uas lees txais cov xim nkag tau yooj yim thiab muaj qhov zoo tshaj plaws weldability, tseem ceeb heev rau cov kab sib dhos tsis siv neeg.
Unexposed Parts: Internal Cheebtsam xws li lub chassis, reinforcements, thiab lub rooj zaum thav duab tsis xav kom zoo nkauj zoo tag nrho tab sis xav tau kev tiv thaiv ntau tshaj plaws. Ntshiab kub-dip galvanized steel yog cov khoom xaiv ntawm no. Nws tso cai rau cov neeg tsim khoom siv nyias nyias, sib zog ntsuas ntawm cov hlau muaj zog kom txo tau tag nrho lub tsheb hnyav - txhim kho roj efficiency-thaum ua kom lub thav duab tsis xeb tawm ntawm txoj kev tshuaj tsuag los yog ntsev.
Kev Ua Liaj Ua Teb & Tsiaj Tsiaj Txhaum Cai (Lub Chemical Resistor)
Kev ua liaj ua teb nthuav tawm ib qho kev sib tw tshuaj lom neeg uas tus qauv tsim tsis muaj: muaj ammonia. Grain silos, barns, thiab tsiaj cwjmem yog tas li raug rau ya raws thiab tsiaj pov tseg.
Thaum Galvalume (ib qho txhuas-zinc alloy) yog qhov zoo tshaj plaws hauv ntau qhov chaw huab cua, nws ua haujlwm tsis zoo hauv cov chaw kaw tsiaj. Cov ammonia pom nyob rau hauv urea thiab manure reacts aggressively nrog txhuas, ua rau sai txheej degradation. Galvanized Steel Chev yeej nyob rau hauv qhov chaw tshwj xeeb no vim tias nws cov zinc txheej ntshiab muaj kev tiv thaiv zoo rau cov alkaline tebchaw. Rau cov neeg ua liaj ua teb thiab cov neeg tsim khoom ua liaj ua teb, xaiv cov qauv galvanized steel tshaj aluminium-raws li lwm txoj hauv kev yog feem ntau qhov sib txawv ntawm lub silo kav ntev li 10 xyoo piv rau 30 xyoo.
HVAC & Hluav Taws Xob Enclosures
Nyob rau hauv lub tshuab thiab hluav taws xob sectors, formability thiab electromagnetic zog ua ntej nrog corrosion kuj.
Ductwork: HVAC ducting cuam tshuam nrog kev tsim khoom, suav nrog nruj hems thiab crimps. Daim ntawv thov no xav tau 'Lock-Forming Quality' (LFQ) steel. Cov khoom siv LFQ yog ua tiav los xyuas kom meej cov zinc txheej adheres nruj nreem rau lub hauv paus hlau txawm tias thaum khoov 180 degrees. Yog tias tsis muaj qhov tshwj xeeb no, zinc yuav flake lossis tev ntawm qhov khoov, tawm hauv cov hlau raug rau qhov sib xyaw thiab xeb hauv qhov cua.
Cov Hluav Taws Xob Hluav Taws Xob: Cable tais, cov kav dej, thiab cov khoom siv hluav taws xob siv cov hlau rau nws lub peev xwm tiv thaiv hluav taws xob (EMI) tiv thaiv. Cov txheej zinc tiv thaiv cov txheej txheem tseem ceeb no los ntawm ib puag ncig corrosion tsis cuam tshuam nrog cov hlau cov khoom sib nqus, kom ntseeg tau tias cov khoom siv hluav taws xob muaj zog tiv thaiv thiab qhuav.
Matching txheej yees siv kawg
Tsis yog tag nrho cov zinc txheej yog tsim sib npaug. Nkag siab txog cov txheej txheem tsim khoom thiab cov txiaj ntsig tshwj xeeb yog qhov tseem ceeb rau kev sib piv cov khoom siv rau nws lub neej thiab ib puag ncig.
Kub-Dip Galvanized (HDG) vs. Electrogalvanized (EG)
Cov txheej txheem ntawm daim ntawv thov kev hloov pauv cov yam ntxwv ntawm cov khoom kawg. Kub-Dip Galvanized (HDG) cuam tshuam nrog kev hla cov hlau ncaj qha los ntawm da dej ntawm zinc molten. Qhov no tsim ib qho kev sib raug zoo ntawm cov zinc thiab cov hlau, uas ua rau cov txheej txheem tuab dua thiab ruaj khov dua. HDG yog qhov kev xaiv zoo tshaj plaws rau sab nraum zoov, lub luag haujlwm hnyav, thiab kev siv cov qauv zoo li lub hnub ci racking thiab kev tsim kho framing qhov siab tshaj plaws thaiv kev tiv thaiv yog tsis sib tham.
Hauv qhov sib piv, Electrogalvanized (EG) steel yog tsim los ntawm electroplating zinc rau saum npoo hlau. Cov txheej txheem no yields ntau thinner, zoo ib yam, thiab matte tiav. Thaum nws muaj kev tiv thaiv corrosion tsawg dua HDG, nws muab qhov zoo tshaj plaws rau kev pleev xim. EG yog qhov zoo tagnrho rau kev siv sab hauv tsev, xws li cov khoom siv hauv tsev, cov khoom siv computer, thiab cov khoom siv sab hauv sab hauv uas qhov tseeb thiab kev zoo nkauj tshaj qhov huab cua tsis zoo.
Txheej Thickness Designations (G-Scale)
Nyob rau hauv ASTM A653 tus qauv, txheej hnyav yog tsim los ntawm 'G' ua raws li tus lej sawv cev rau tag nrho cov hnyav zinc ntawm ob sab ntawm daim ntawv (hauv pua pua ntawm ib ooj ib square feet). Kev nkag siab txog qhov ntsuas no yog qhov tseem ceeb rau kev yuav khoom.
| Tsim |
Zinc Thickness |
Primary Application |
Hom Ib puag ncig |
| G30/G40 |
Teeb |
Cov khoom siv sab hauv, rooj tog zaum hauv chaw ua haujlwm, studs |
Kev tswj kev nyab xeeb, qhuav hauv tsev. |
| G60 |
Nruab nrab (Standard) |
Commercial HVAC, sab hauv framing, garage qhov rooj |
Qee zaus noo noo, tiv thaiv sab nraum zoov. |
| G90+ |
Hnyav |
Roofing, ua liaj ua teb silos, sab nraum zoov infrastructure |
Kev raug ncaj qha rau nag, daus, thiab cov pa phem. |
Cov lej siab dua 'G' ncaj qha cuam tshuam rau cov zinc txheej tuab. Txij li zinc corrodes ntawm tus nqi kwv yees, G90 txheej yuav theoretically kav 50% ntev dua li G60 txheej hauv tib qhov chaw ua ntej xeb liab tshwm rau ntawm lub hauv paus hlau.
Spangle Variations (Aesthetic vs. Functional)
Lub 'spangle' yog hais txog cov crystalline snowflake qauv pom nyob rau saum npoo ntawm kub-dip galvanized hlau. Keeb kwm, ib tug loj, bold spangle tau pom raws li ib tug kos npe rau ntawm zoo. Niaj hnub no, spangle loj yog tswj rau cov kev xav tau tshwj xeeb.
Tsis tu ncua Spangle: Nta cov tsoos, pom crystalline zoo. Nws yog qhov tsim nyog rau kev tsim kho dav dav, qhov tsis raug, thiab kev siv sab nraum zoov uas zoo nkauj yog qhov thib ob rau kev ua haujlwm.
Zero lossis Tsawg Spangle: Ua los ntawm inhibiting crystal kev loj hlob thaum lub caij txias. Qhov kev ua tiav no yog xav tau rau cov khoom siv tsheb lossis cov khoom siv hluav taws xob uas yuav raug pleev xim. Lub zero-spangle nto ua kom ntseeg tau tias cov crystalline kev ntxhib los mos tsis telegraph los ntawm cov xim, uas ua rau ib tug du, high-gloss tiav.
Kev ntsuam xyuas tseem ceeb: Qhov twg tsis siv Galvanized Steel
Kev ntsuam xyuas cov ntaub ntawv ncaj ncees yuav tsum lees paub cov kev txwv. Thaum Galvanized Steel Coil muaj ntau yam, nws tsis yog kev kho thoob ntiaj teb-tag nrho. Qee qhov chaw yuav degrade zinc sai, ua rau kim tsis ua haujlwm.
Kev txwv ntawm ntug dej hiav txwv
Cov dej ntsev yog cov kryptonite ntawm galvanized hlau. Nyob rau hauv high-salinity ib puag ncig - feem ntau txhais raws li nyob rau hauv 1 mus rau 3 mais ntawm ntug hiav txwv dej - ntsev tsuag accelerates corrosion ntawm zinc loj. Cov tshuaj chlorides hauv dej hiav txwv txau ua rau cov tshuaj tiv thaiv patina uas feem ntau ua rau zinc. Rau tej yaam num nyob rau hauv cov cheeb tsam no, qhia galvanized steel feem ntau yog ib qho yuam kev. Hloov chaw, pawg neeg yuav khoom yuav tsum pom zoo rau Aluminium lossis Stainless Steel, uas muaj kev tiv thaiv zoo tshaj plaws rau marine corrosion.
Galvanized vs Galvalume (Al-Zn)
Cov neeg yuav khoom feem ntau tsis meej pem Galvanized steel nrog Galvalume, tab sis lawv muaj cov kev ua tau zoo sib txawv. Galvalume ua ke nrog txhuas, zinc, thiab silicon. Nyob rau hauv dav dav atmospheric tej yam kev mob, Galvalume muaj peev xwm muab 2 mus rau 4 lub sij hawm lub neej ntawm galvanized steel vim lub barrier tiv thaiv ntawm txhuas.
Txawm li cas los xij, galvanized steel tuav ib qho tseem ceeb kom zoo dua nyob rau hauv 'ntug creep.' Thaum ib daim ntawv txiav, cov ntug steel nyoos raug nthuav tawm. Zinc muaj zog heev thiab yuav tsiv teb tsaws los tiv thaiv qhov kev txiav ntug (kev kho tus kheej). Aluminium yog passive ntau dua thiab muaj kev tiv thaiv tsawg dua ntawm cov npoo. Yog li ntawd, siv Galvanized steel rau daim ntawv thov uas nws kim heev sib sau, xuas nrig ntaus, los yog shearing, thiab rau tsiaj kaw. Xaiv Galvalume rau cov qauv kev lag luam vov tsev nrog tsawg perforations.
Cia Risks (White Rust)
Ib qho tsis ua hauj lwm tshwm sim ua ntej cov khoom txawm ntsia. Yog tias cov galvanized coils khaws cia rau hauv cov khoom ntub dej, qhov cua tsis zoo, cov dej noo nkag mus rau ntawm cov txheej hlau. Qhov no deprives zinc ntawm cov pa roj carbon dioxide xav tau los tsim nws ruaj khov txheej tiv thaiv carbonate. Hloov chaw, nws tsim zinc hydroxide - ib qho dawb, hmoov uas hu ua 'White Rust.' Qhov kev puas tsuaj no tuaj yeem mus tas li. Yuav kom txo tau qhov no, yuav tsum tau kho passivation (chromating los yog oiling) thaum lub sij hawm yuav khoom thiab xyuas kom meej huab cua tswj warehousing.
Kev txiav txim siab ua lag luam rau kev yuav khoom
Sourcing steel coil yog qhov nyuaj tshaj qhov nrhiav tus nqi qis tshaj ib tuj. Ntau yam kev lag luam cuam tshuam rau Tag Nrho Tus Nqi Ntawm Cov Tswv Cuab (TCO) thiab kev tsim ua tiav.
Tus nqi tsav tsheb dhau tus nqi qis
Daim ntawv kawg kawg rau galvanized kauj yog hnyav heev los ntawm zinc surcharges. Txij li zinc tau pauv thoob ntiaj teb ntawm LME (London Hlau Txauv), nws tus nqi hloov pauv ntawm nws tus kheej ntawm cov hlau. Thicker coatings (G90 vs G60) tau txais zinc ntau dua. Tsis tas li ntawd, cov qib high-strength low-alloy qib (HSLA) hais kom cov nqi zog. Cov neeg yuav khoom kuj tseem yuav tsum tau them tus nqi rau kev kho mob saum npoo xws li cov tshuaj tiv thaiv ntiv tes lossis cov roj hnyav, uas tiv thaiv cov khoom siv thaum lub sijhawm thauj mus los tab sis ntxiv rau cov kab hauv qab.
Formability & Fabrication Metrics
Xaiv cov qib hlau tsis raug tuaj yeem nres ib txoj kab ntau lawm. Rau cov tuam txhab HVAC, ** Xauv-forming Zoo (LFQ) ** yog qhov tseem ceeb; Nws ua kom lub txheej tsis tawg thaum lub sij hawm txhoj puab heev dabtsi yog khoov. Conversely, automotive thiab cov khoom siv stampers xav tau ** Drawing Quality (DQ) ** los yog ** Deep Drawing Quality (DDQ) ** steel. Cov qib no muaj qhov tshwj xeeb microstructure uas tso cai rau lub hauv paus hlau mus rau hauv cov duab nyuaj (xws li lub dab dej lossis lub tsheb fender) yam tsis muaj kev sib cais. Tsis quav ntsej cov kev ntsuas no ua rau muaj cov khoom seem thiab cov khoom siv khib nyiab.
Sustainability & TCO
Txawm hais tias tus nqi nce siab dua piv rau cov qauv 'dub' steel, galvanized steel muaj qhov cuam tshuam txog Lifecycle Tus Nqi Ntsuas. Los ntawm kev tshem tawm qhov yuav tsum tau ua kom rov ua dua lossis kho rau 20 txog 50 xyoo, cov khoom siv them rau nws tus kheej. Tsis tas li ntawd, zinc-steel composite yog 100% recyclable. Thaum kawg ntawm lub tsev lub neej, cov hlau tuaj yeem rov qab tau thiab yaj los ua cov khoom tshiab yam tsis tau poob ntawm cov khoom, ua raws li cov hom phiaj kev ruaj ntseg niaj hnub.
Xaus
Galvanized steel kauj tsis yog ib qho, monolithic khoom; nws yog ib tug dav spectrum ntawm specifications tailored los cuam tshuam nrog tej ib puag ncig. Los ntawm nyias, pleev xim rau ntawm lub tshuab ntxhua khaub ncaws mus rau lub luag haujlwm hnyav G90 tiv thaiv ntawm txoj kev loj guardrail, kev vam meej nyob ntawm qhov tseeb. Qhov sib txawv ntawm ib txoj haujlwm uas kav ntau xyoo thiab ib qho uas ua tsis tiav hauv ob peb xyoos feem ntau los rau kev nkag siab txog qhov sib txawv ntawm qhov kub-dip thiab electro-galvanizing, los yog paub txog thaum twg yuav hloov mus rau txhuas hauv cov ntug dej hiav txwv.
Kev ua tiav zoo pib nrog kev txhais ib puag ncig. Puas muaj ammonia tam sim no? Cov khoom puas yuav ntsej muag tsis tu ncua los yog UV hluav taws xob? Thaum cov kev hloov pauv no tau teeb tsa, xaiv qhov tsim nyog txheej hnyav thiab qib steel ua cov ntaub ntawv-tsav kev txiav txim siab tsis yog kev kwv yees. Peb xav kom koj thov kev sab laj cov khoom lossis cov khoom siv tshwj xeeb los txheeb xyuas cov txheej txheem kev ua raws thiab qhov chaw tiav ntawm koj tus kheej cov kab tsim khoom ua ntej cog lus rau tag nrho.
Cov FAQ
Q: Qhov txawv ntawm G60 thiab G90 galvanized steel yog dab tsi?
A: Qhov txawv yog nyob rau hauv lub thickness ntawm zinc txheej. G60 muaj tag nrho cov txheej hnyav ntawm 0.60 oz / sq ft, thaum G90 muaj 0.90 oz / sq ft. G90 muab ib qho kev tiv thaiv thicker, muab kwv yees li 50% kev pab cuam lub neej nyob rau sab nraum zoov ua ntej cov zinc yog depleted thiab liab xeb cov ntaub ntawv. G60 feem ntau yog siv rau sab hauv tsev lossis kev lag luam me me, qhov G90 yog tus qauv rau sab nrauv vov tsev thiab ib puag ncig hnyav.
Q: Puas tuaj yeem galvanized steel coil pleev xim?
A: Yog, tab sis nws yuav tsum tau npaj kom raug. Cov chaw tshiab galvanized feem ntau yog du lossis chemically reactive rau cov qauv xim kom ua raws. Koj yuav tsum siv cov primer tshwj xeeb lossis kev kho ua ntej kom etch saum npoo. Xwb, koj tuaj yeem yuav 'Galvannealed' steel lossis 'Bonderized' steel, uas yog tshuaj kho los yog ua kom sov ntawm lub zeb tshwj xeeb los muab qhov chaw tam sim, pleev xim rau qhov tsis muaj kev npaj ua haujlwm ntxiv.
Q: Puas yog galvanized steel xeb?
A: Thaum kawg, yog. Galvanized steel resists xeb los ntawm 'sacrificial' txheej txheem uas cov zinc corrodes es tsis txhob ntawm cov hlau. Ntau xyoo, zinc txheej yuav maj mam deplete. Thaum cov zinc tau noj tag nrho, cov hlau substrate raug nthuav tawm, thiab 'Red Rust' (hlau oxide) yuav tsim. 'White Rust' yog ib qho teeb meem sib txawv - ib qho chaw khaws cia uas tshwm sim thaum zinc raug cov dej tsis muaj cua.
Q: Puas yog galvanized steel tsim nyog rau thaj chaw marine?
A: Feem ntau, tsis yog. Hauv ib puag ncig hauv 1-3 mais ntawm cov dej ntsev, cov ntsiab lus chloride siab hauv huab cua nrawm zinc corrosion, stripping txheej tiv thaiv sai. Rau kev raug marine ncaj qha, stainless hlau lossis txhuas yog qhov kev xaiv zoo dua. Yog hais tias galvanized steel yuav tsum tau siv, nws yuav tsum tau ib tug hnyav txheej hnyav (G210 los yog siab dua) los yog ib tug ntxiv tiv thaiv xim system (duplex txheej).
Q: Lub neej ntev ntawm galvanized steel kauj yog dab tsi?
A: Lub neej ua haujlwm sib txawv raws li cov pa phem thiab noo noo. Nyob rau hauv qhov chaw qhuav, nyob deb nroog, tus qauv G90 txheej tuaj yeem kav ntev dua 50 xyoo. Hauv kev lag luam hnyav lossis hauv nroog qhov chaw uas muaj kuab paug ntau dua, tib txheej txheej yuav kav li 20 txog 25 xyoo. Lub thicker zinc txheej, lub neej ua haujlwm ntev.
