Optimization of Vacuum Brazing Parameters for Inconel 718 and 17-4PH Stainless Steel by Taguchi Method

• Main Authors: CHENG,HUNG-SHENG, 鄭弘昇
• Other Authors: LI,I-KANG
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/80701038985140599912

碩士 === 大葉大學 === 機械與自動化工程學系 === 102 === This study is based on the Taguchi Method to optimize the parameters of similar and dissimilar vacuum brazing on nickel-base superalloy 718/17-4PH, and evaluate the maximum tolerable values in precision design of weld joint. Adopted the Taguchi Orthogonal Array method (L9(34)) to find optimal parameters. We also control the parameters (brazing temperature, retention time, surface roughness, holding force) to design the experimental conditions and testing. After calculating and analyzing in our study, the optimal bonding parameters by using BNi-2 filler for Inconel 718 similar brazing are giving: brazing temperature -1050 ℃, holding time -50 minutes, the surface roughness -#800 and holding force -5 m‧N. The optimal parameters of experiments confirm, the compressive shear strength about 652 MPa. In addition, adopting fixed surface roughness (#800), holding force (5 m‧N), brazing temperature 1070 ℃ and holding times 50 minutes in similar gap testing, the result of maximum gap on capillary phenomenon is 258 μm and the furthest flowing distance is 9672 μm. Moreover, the holding times and brazing temperature increase causes the capillary phenomenon more intense. In multiple furnace testing, we discover that after go into furnace, the strength of weldment would drop to about 0.07 %; the optimal compressive shear strength occurred at five times furnace and three times heat treatment (about 632 MPa). After six times furnace and two times heat treatment, the strength of weldment would begin to decline. Then compressive shear strength after heat treatment would slightly rebounded. If we change the brazing filler to AgCuTi fillter in vacuum brazing, then in brazing temperature of 920 ℃ and holding time of 10 minutes, the compression shear stress would about 206 MPa. Using alloy filler BNi-2 of vacuum brazing to Inconel 718/17-4PH. In Taguchi Orthogonal Array method (L9(34)), After analysis of the bonding parameters for optimal. Brazing temperature -1030 ℃, holding times -10 minutes, the surface roughness -#400 and holding force -5 m‧N. If the optimization parameter carries on the confirmation experiment, then may obtain presses shearing strength approximately 426 MPa. Moreover, select the fixed surface roughness (#400) and holding force (5 m‧N) gap test of heterogeneity. When the brazing temperature of 1070 ℃, holding times 50 minutes maximum gap of 298 μm obtained with capillary phenomenon flow furthest distance 9672 μm. By comparing the test results found. Both the Inconel 718 and 17-4PH homogeneous or heterogeneous brazing gap test results show. Increase the holding times and brazing temperatures will also enhance the capillary phenomenon the occurrence.