1. Kev xaiv cov txheej txheem vuam
2. Filler Hlau Xaiv (Qhov tseem ceeb rau Corrosion Match)
Txoj Cai Core: Siv weathering-qib fillers nrog Cu/P/Cr/Ni los xyuas kom meej lub weld lub xeb txheej phim lub hauv paus hlau thiab tsis txhob galvanic corrosion.
SMAW: E7016-G (AWS) / J507CrNiCu (GB); qhuav ntawm 350-400℃rau 1-2 teev, tuav ntawm 100-150℃hauv qhov cub thermal.
GMAW/FCAW: ER50-6NiCu (GMAW) or E81T1-W2C (FCAW); khaws cia rau hauv cov thawv kaw kom tiv thaiv kom tsis txhob ya raws.
GTAW: ER50-6NiCu (0.8-1.2 hli txoj kab uas hla) rau cov ntawv nyias thiab cov hauv paus hniav.
3. Kev npaj Pre-Weld
Nto ntxuav: Tshem tawm cov nplais zeb, xeb, roj, thiab cov dej noo nyob rau hauv 20 hli ntawm qhov sib koom ua ke siv cov hlau txhuam, grinder, los yog hnyav (acetone / degreaser) los tiv thaiv porosity thiab hydrogen cracking.
Kev sib koom tes tsim:
Butt joints: Square groove for t ≤6 mm (root gap 1–2 mm); V‑groove (60–70° included angle, 1–2 mm root face) for t >6 hli.
Fillet pob qij txha: ceg ntev=0.7 × phaj thickness; lap joints min. sib tshooj 25 mm.
Tack welds: Siv tib qhov muab tub lim raws li lub ntsiab vuam; ntev 10-15 mm, nrug 150-200 mm; tshem tawm cov tacks ua ntej lub ntsiab vuam.
Preheating:
t Tsawg dua lossis sib npaug li 16 hli, temp Ntau dua lossis sib npaug li 5 degree: Tsis xav tau preheat.
t >16 mm or ambient ≤0°C: Preheat to 80–150°C (use a pyrometer to verify); for t >25 hli, preheat rau 100-150 degree.
Preheat tag nrho cheeb tsam sib koom ua ke (Ntau dua lossis sib npaug li 50 mm ntawm ob sab) sib npaug kom tsis txhob muaj cov thermal gradients.
4. Welding Parameters (Tsuas Kub Input & Interpass Control)
Kub Input: Keep at 15–25 kJ/cm (avoid >30 kJ / cm) los tiv thaiv grain coarsening thiab txo toughness hauv HAZ.
SMAW: 3.2 hli electrode → 100–140 A, 22–26 V, mus ncig ceev 150–200 mm / min.
GMAW: 1.0 mm xaim → 180–220 A, 24–28 V, 20–25 L/min Ar+CO₂, 200–300 mm/min.
Interpass Temperature: Khaws ntawm 80-150℃(max Tsawg dua lossis sib npaug li 200 degree) kom tsis txhob HAZ overheating; txias nrog yuam cua yog tshaj qhov txwv.
Arc & Travel: Siv luv arcs kom txo tau spatter thiab porosity; tswj kev khiav ceev kom zoo ib yam rau cov hlaws zoo ib yam.
Multi-Pass Vuam: Ntxuav slag kom huv si ntawm qhov chaw; zom tej yam tsis xws luag (xws li, undercut, tsis tiav fusion) ua ntej dhau mus.
5. Kev Kho Mob Tom Qab Weld
Kev kho tam sim ntawd:
Remove slag, spatter, and weld spatter with a hammer, wire brush, or grinder; grind smooth any undercut >0.5 hli.
Back-gouge ib leeg-sided welds kom tshem tawm cov hauv paus tsis xws luag, tom qab ntawd rov txuas sab nraub qaum kom nkag mus rau tag nrho.
Kev ntxhov siab:
For thick sections (t >20 mm) lossis cov qauv kev ntxhov siab: Kev kho cua sov tom qab vuam (PWHT) ntawm 550–620℃rau 1–2 teev ntawm 25 mm thickness, ua raws li cov cua kub cua txias kom tsawg dua lossis sib npaug li 150℃ua ntej cua txias.
Rau cov ntu nyias (t Tsawg dua lossis sib npaug li 16 hli): Tsis xav tau PWHT; siv cov txheej txheem qis-hydrogen thiab preheat kom zoo los tswj cov kev ntxhov siab seem.
Kev tiv thaiv corrosion:
Tsis txhob pleev xim rau tag nrho cov vuam; es tsis txhob, siv ib tug weathering steel passivator los yog patina accelerator rau lub weld thiab HAZ los txhawb cov txheej txheej xeb.
Nyob rau hauv high-ntse ntsev ntawm ntug dej hiav txwv: Thov ib tug nyias matte pob tshab glaze rau lub weld los txhim khu corrosion kuj tsis zais qhov xeb zoo nkauj.
