<p>This study investigates the influence of heating duration (50-30 min) in a continuous furnace on microstructure evolution and interfacial properties of CuSn10Pb10/42CrMoS4 bimetallic composite cylinder block. Through systematic characterization using OM, SEM, EBSD, XRD, and microhardness testing, the quantitative relationships between heating duration, Pb-phase morphology, interfacial diffusion behavior, and mechanical performance were established. Results demonstrate that decreasing heating duration leads to inhomogeneous Pb-phase distribution via weakening atomic diffusion, with irregular spherical Pb particles increasing from 48 μm (50 min) to 181 μm (30 min). The interfacial diffusion layer thickness decreases from 5.25 μm to 0.87 μm as heating duration shortens. Shear strength declines significantly from 132 MPa (50 min) to 106 MPa (30 min), accompanied by a transition from ductile fracture (dimples) to interfacial debonding (intergranular cracking). A longer heating duration facilitates fine-grained interfacial structures dominated by small grain orientation, which impede dislocation motion and enhance bonding strength. Conversely, insufficient diffusion induces high concentration gradients (&gt;6,400 μm⁻¹), deteriorating interfacial integrity. The optimal heating duration of 50 min achieves balanced Pb-phase homogeneity (20 μm discontinuous dots) and interfacial bonding of 132MPa. This work elucidates the thermal-diffusion-structure-property correlations in bimetallic composites, providing theoretical guidance for precision manufacturing of high-performance hydraulic components under extreme service conditions.</p>