Laser-Arc Hybrid Welding of Dissimilar Titanium Alloy and Stainless Steel Using Copper Wire
- PDF / 6,221,893 Bytes
- 14 Pages / 593.972 x 792 pts Page_size
- 12 Downloads / 196 Views
NTRODUCTION
THE joining of dissimilar titanium (Ti) alloy and stainless steel (SS) is of interest for chemical and nuclear applications. Previous studies have shown that the joining of Ti alloy and SS suffers from two major challenges.[1–4] One is the formation of brittle intermetallic compounds (IMCs) between Ti and Fe. The other is the occurrence of cracks and residual stresses that are caused by the great differences in thermal properties between Ti and SS. For example, the thermal expansion coefficients of Ti and SS are 8.4 9 10 6 K 1 and 16.6 9 10 6 K 1, respectively. Considering the above difficulties, the interlayers such as Cu,[5] Ag,[6] Ni,[7,8] Al,[9] and Mg[10] have been used to suppress the formation of Ti/Fe IMCs during welding. Among them, Cu would be a potential candidate to meet the needs of industry. Firstly, the melting point of Cu is higher than that of Al or Mg, denoting that the joint using Cu interlayer has better high-temperature performance. Besides, the melting point of Cu is not too high, which would be better to increase the adjustable range of welding parameters. Secondly, Cu is cheaper than Ag and Ni, which reduces the manufacturing costs. Thirdly and importantly, Cu does not form any IMCs with steel, although Cu-Ti binary phase diagram indicates the occurrence of Cu2Ti, Cu3Ti2, CuTi, and CuTi2 with increasing Cu content. Kundu et al. found that the tensile strength of diffusion-bonded commercial pure Ti and 316SS was up to 318 MPa when Cu was used as the MING GAO, Associate Professor, CONG CHEN and LEI WANG, Doctoral Students, ZEMIN WANG and XIAOYAN ZENG, Professors, are with the Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, P.R. China Contact e-mail: [email protected] Manuscript submitted May 27, 2014. METALLURGICAL AND MATERIALS TRANSACTIONS A
interlayer.[5] Similarly, Wang et al. found that the tensile strength of electron beam-welded dissimilar Ti15Al3V alloy and 316SS with Cu interlayer was up to 224 MPa.[11] Refaey and Tillmann found that accepted diffusion-bonded pure Ti and mild steel was obtained in lap configuration by using Cu12Mn2Ni interlayer.[1] Nowadays, diffusion bonding/brazing has been one of the most common processes to join Ti alloy and SS. But it is impractical for mass production and needs great care in surface preparation. Friction stir welding (FSW) was employed to join dissimilar Ti alloy and SS recently.[12,13] Although the results showed that the tensile strength of FSWed Ti/SS joint was up to 400 MPa, the high melting point of either steel or Ti alloy is a big challenge for long-term usage of stir pin. Being a high efficiency and flexibility technique, laser welding has made great achievements in joining dissimilar metals, such as Mg/steel,[14] Mg/Ti,[15] Al/ Ti,[16,17] Cu/steel,[18] and Al/steel.[19] For example, our previous study has demonstrated that Ti6Al4V/316SS joints of acceptable quality and properties can be obtained by fiber laser welding with Mg interlayer,[10] and the cross-weld strength of the
Data Loading...
