B. Zorc
Institut za varilstvo
1000 Ljubljana, Ptujska 19
Institut za varilstvo, Ljubljana
L. Kosec, FNT, Odsek za metalurgijo in materiale, Ljubljana
S spajkanjem v zascitni atmosferi dobimo ciste, neoksidirane
povrsine izdelkov. V argonu in razkrojenem amoniaku smo spajkali
tanke plocevine (0,5 do 1,0 mm) nikljevih zlitin in nerjavnih
jekel. Uporabili smo visokotemperaturni nikljevi spajki B-Ni 7
(Ni-Cr-P) in B-Ni 1 (Ni-Cr-Fe-Si-B). Raziskali smo vpliv pogojev
spajkanja in kemicne sestave osnovnih materialov na omocljivost
obeh spajk. Analizirali smo reakcije med spajkama in osnovo ter
odvisnost mehanskih lastnosti od mikrostrukture spajkanih spojev.
Z nacinom spajkanja in naknadno toplotno obdelavo smo evtekticno
mikrostrukturo v rezi spremenili v enofazno trdno raztopino. Na
ta nacin smo povecali duktilnost in odpornost spoja proti
nastanku in sirjenju razpoke.
Kljucne besede: spajkanje v zascitni atmosferi, korozijsko
odporne zlitine in spajke, omo~ljivost spajk, mikrostruktura
spoja, mehanske lastnosti, toplotna obdelava
In gas-shielded brazing, a clean, non-oxidized surface of
products is obtained. Thin plates (0.5 - 1.0 mm) of nickel alloys
and stainless steels were brazed in argon and in decomposed
ammonia. High-temperature nickel-based brazing alloys B-Ni 7
(Ni-Cr-P) and B-Ni 1 (Ni-Cr-Fe-Si-B) were used. The influence of
brazing and of chemical composition of the parent metals on the
wettability of each of the brazing alloys was studied. Reactions
between the brazing alloys and the parent metal as well as
dependency of mechanical properties on the microstructure of the
brazed joints were analyzed. With the application of the brazing
process and heat treatment after brazing, eutectic microstructure
in the gap was changed into one-phase solid solution. In this
way, ductility and crack resistance of the joint were increased.
Key words: gas-shielded brazing, corrosion-resistant alloys and
brazing filler metals, wettability of brazing filler metals,
microstructure of joint, mechanical properties, heat treatment