Porous metal-bonded cubic boron nitride (CBN) grinding wheels are fabricated by employing ammonium hydrogen carbonate (NH₄HCO₃) as pore-forming agents to avoid workpiece burn, improve ground surface quality and service life during grinding Ti–6Al–4V titanium alloys. The graphite particle concentrations are optimised with the flexural strength and interface morphology between the metallic matrix and grains. The grinding performance, including grinding temperature, material removal rate, grinding ratio, grains wear and ground surface quality of the porous CBN wheels and silicon-carbide abrasive wheels is evaluated during grinding Ti–6Al–4V titanium alloys without cooling lubricants. Results indicate that porous CBN wheels with 10% (mass fraction) graphite particles are optimized in terms of the wettability between the metallic matrix and abrasive grains as well as the flexural strength. In addition, porous CBN wheels exhibit high porosity and promising comprehensive grinding performance. In comparison with the silicon-carbide abrasive wheels, a lower grinding temperature (approximate 250℃) and better ground surface quality can be achieved by porous CBN wheels. Moreover, the material removal rate and grinding ratio of porous CBN wheels reach about 4 and 2 times than that of the silicon-carbide abrasive wheels under the same conditions.