MODELING AND OPTIMIZATION OF BRAZING FOR AA 6061/ AISI 304LUSING GREY RELATIONAL ANALYSIS

In this paper, joining of aluminum alloy 6061 as annealed and austenitic stainless steel AISI 304L was carried out by furnace brazing at (620 and under protection of argon gas. Lap joints of AA 6061/AISI 304L were investigated with AlSi12, and AlSi10Cu4 filler alloys in form of paste using different brazing times (5, 10, 15, and 20 min). The optimum shear strength of the joint reached to (3.36 KN) at (10 min) using AlSi12 filler alloy. While, the maximum shear strength of the joint with AlSi10Cu4 filler alloy reached to (2.59 KN) at (15 min). In addition, microhardness of the interfacial layer of the joint with filler AlSi10Cu4 was higher than the microhardness value of the interfacial layer of the joint with AlSi12 filler alloy at the same brazing conditions. For each filler, at brazing time (5 min), lap joints were weak with minimum shear strength. Finally, the corrosion behavior of brazing joints in 3.5% NaCl was studied to evaluate the rate of corrosion for brazing joints. The minimum corrosion rate is achieved (0.005209mpy) (1.68 by (10 min) using AlSi12 filler alloy. Grey relational analysis (GRA) based on Taguchi method was applied using two factors, brazing time (T) and filler type (F) with four levels. The results showed that the variation of brazing time is the most affective parameter on the shear force, corrosion rate, and microhardness of the interfacial reaction layer. While, the type of filler alloy is slightly affective on the output response. In addition, these results manifested that the Taguchi based grey relational approach improves the properties of the output response of the joined AA 6061 and AISI 304L