Brazeability of powder aluminum brazing filler metals with non-corrosive flux

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:115522

Takemoto, T; Matsunawa, A; Ujie, T ^[1]

---

1. and others

Various brazed aluminum products, mainly heat exchangers, have been widely used especially in automobiles and electric power industries. They have been produced by using brazing sheet; however, recently the demand to braze the complicated shape is increasing, leading to the necessity for setting brazing filler metal at braze parts instead of using brazing sheet. Therefore, the present work aimed to investigated the brazeability of aluminum powder filler metal in nitrogen gas atmosphere using KAIF{sub 4}-K{sub 3}AIF{sub 6} system noncorrosive brazing flux. By considering the applicability of filler metal, brazing pastes were made of powder filler metal, flux and organic binder. AI-Si powder brazing filler metals were made by automization. T-type specimen was made by A3003 base metal with thickness of 2 mm. in the present experiment, fillet formabiltity, the percentage of the length of formed fillet against the length of vertical member wall at each side, was adopted to evaluate brazeability. The shape of the atomized powder depended on atomize atmosphere and atomizing gas. Sound fillet formation was achieved on the full length of both sides of the vertical member under the condition of appropriate surface treatment and sufficient flux content. Decrease in flux content gave partial fillet formation at the opposite side of the paste set side. Further decrease brought the partial fillet formation at the paste set side also. The paste made of air-atomized powder required more flux content to achieve 100% fillet formation at the opposite side. On the other hand, argon-atomized powders formed fillet in full length using paste with less flux content. powders sorted to remove fine particles and powders with low oxygen content were found to be suitable for brazing filler metal powders, because they required less flux content to obtain 100% fillet formation under the same amount of paste.

• OSTI ID: 115522
• Report Number(s): CONF-9404233--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
ALUMINIUM OXIDES
BINDERS
BRAZED JOINTS
BRAZING
CHEMICAL COMPOSITION
FILLER METALS
METALLURGICAL FLUX
POWDER METALLURGY
SURFACE AREA