Formation of Sectoral Residual Thermoplastic Tension Fields in Circular Saw Blade

Abstract

The efficiency of a stationary circular saw is determined by the performance and operational reliability of the woodcutting unit. During operation, the circular saw blade is exposed to a variety of complex loads and thermal conditions. The rigidity and stability of the saw blade determine its capacity to resist the perturbing cutting forces. The cutting compound itself is a thin disc made of steel with a hole in the middle that has a serrated cutting edge. It consists of three areas: peripheral, middle, and central. The stability of the saw blade is determined by the middle and peripheral parts. The increase in durability is achieved by plastic deformation to form the strip boundaries of the radial sections. These parts are treated by forging in both national and international practice. Normalization of loads on the blade in case of local mechanical contact with the working body is formed in the strip boundaries of the radial sections through the formation of places with plastic deformation of the metal, which rearrange the loads and place them in the radial direction. At the same time, countertension appears from the adjoining sections, leading to mutual “repulsion” of them and the creation of compressive tension that compensates for the forces of centrifugal acceleration, thermal heating of separate areas of the saw blade, external longitudinal and transverse bending tension that arise during wood processing. The combined interaction of all adjoining sections provides the tension and stability of the saw blade. The creation of the radial sections by forging has some significant disadvantages. Their elimination requires a fundamentally new approach, such as the formation of the residual stress sections in the saw blade by thermal exposure. It creates a normalized residual thermoplastic tension in the saw blade by a short-time (1–2 s) focused thermal influence on the strip boundaries of the radial sections. The results of the conducted research determined the boundaries of the sections for thermal treatment and the temperature range, which ensure the formation of normalized residual thermoplastic tension in the circular saw blade through concentrated pulsed heating of the strip edges of radial sections. For citation: Melekhov V.I., Solovev I.I. Formation of Sectoral Residual Thermoplastic Tension Fields in Circular Saw Blade. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 146–154. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-146-154

Keywords

• circular saw
• thermoplastic tension
• stability
• focused thermal exposure