In metallic material processing, the microstructural and textural characteristics developed during each manufacturing stage establish the structural foundation for subsequent processing operations, creating substantial hereditary effects throughout the multistage manufacturing chain. This progressive, cross-process accumulation of microstructural and textural evolution makes precise tracing and effective control of microstructural inheritance pathways particularly complex during full-scale manufacturing from the initial ingot to the final TA18 tube blank. Microstructural inheritance forms the basis for structural design and property optimization in TA18 alloys. This investigation employed a 700-mm diameter TA18 alloy ingot as the starting material. The thermomechanical processing route comprised three stages: initial multipass forging in the β-phase field (1150-950 ^oC) followed by forging in the α + β phase field at 900 ^oC to produce a 170-mm diameter rough-forged bar; subsequent processing of the rough-forged bar in the two-phase region at 850 ^oC to obtain a 125-mm diameter finish-forged bar; finally, peeling, drilling, and canned hot extrusion of the finish-forged bar to fabricate tube blanks with inner and outer diameters of 28 and 42 mm, respectively. This study systematically investigates the hereditary evolution of microstructure and texture throughout the processing route from ingot to tube blank in the TA18 alloy and evaluates its impact on mechanical properties to guide the integrated control of multiscale microstructure and performance. The results demonstrate that microstructural hereditary characteristics can be categorized into three primary types. (1) Once established during rough forging, the micron-scale grain size and equiaxed α-phase morphology remain stably inherited in subsequent processing stages. Grain refinement serves as the fundamental basis for increasing axial tensile strength from 400 MPa to 550 MPa and improving elongation. (2) The inheritance of low angle grain boundary (LAGB) fraction exhibits dynamic evolution. The high fraction inherited during the rough- and finish-forging stages contributes to work hardening but negatively affects plasticity; in contrast, the low fraction inherited after extrusion, achieved via dynamic recrystallization, results in plasticity recovery. (3) The inheritance of crystallographic texture is governed by multiple competing mechanisms. The {0001}//axial direction (AD) basal texture and the <\mathrm{10}\overline{\mathrm{1}}\mathrm{0}>//AD texture originating from the central region of the ingot are strongly inherited during subsequent processing, with the intensity of the <\mathrm{10}\overline{\mathrm{1}}\mathrm{0}>//AD texture continuously increasing. The c-axis orientation of the α-phase undergoes controlled evolution during processing: it is randomly distributed after rough forging, transforms into a radial texture after finish forging, and finally develops into a circumferential texture after extrusion. The TA18 alloy controls the inheritance and evolution of crystallographic orientation through the competition and synergy of various mechanisms, including initial crystallographic orientation, deformation, and dynamic recrystallization. The integrated design of TA18 alloy tube blanks, possessing high strength and good plasticity can be achieved by reinforcing beneficial hereditary features (such as fine grains and favorable texture) and interrupting harmful features (such as high LAGB fraction and unfavorable texture).