  In this work, we study the disorder effect on topological metals that support
a pair of helical edge modes deeply embedded inside the gapless bulk states.
Strikingly, we predict that a quantum spin Hall (QSH) phase can be obtained
from such topological metals without opening a global band gap. To be specific,
disorder can lead to a pair of robust helical edge states which is protected by
an emergent $Z_2$ topological invariant, giving rise to a quantized conductance
plateau in transport measurements. These results are instructive for solving
puzzles in {various transport experiments on QSH materials} that are
intrinsically metallic. This work also will inspire experimental realization of
the QSH effect in disordered topological metals.
