  In this paper we detect double-lined spectroscopic binaries (SB2) in five
open clusters: NGC 2243, NGC 2420, NGC 3532, NGC 6253 and NGC 6705 (M 11) using
a method based on high values of the projected rotational velocity when they
are fitted with single star spectral model. Observed spectra were obtained from
ESO archive. The method was validated on sets of synthetic spectra for the
single and binary stars. It is able to reliably select spectroscopic binaries
without confusing them with single stars, if components in binary rotate slowly
and radial velocity separation is sufficiently high. We found 60 SB2
candidates: two in NGC~2243, eight in NGC~2420 and NGC~3532, 17 in NGC 6253 and
25 in NGC~6705. Comparison with literature confirms 18 of them, thus we found
42 new SB2 candidates.
