Abstract
The article investigates the tribological and thermo-oxidative characteristics of liquid drawing lubricants used in the calibration of rolled products after surface shot blasting. This preparation method eliminates the use of traditional sub-lubricant coatings (phosphate, borated), making the liquid lubricant the only barrier that prevents tool wear and forms the product's surface quality. Under conditions of extreme pressure, high drawing speeds, and significant heat generation, the lubricant's performance is determined by its ability to form a stable boundary film with a low friction coefficient and high load-carrying capacity, as well as its resistance to thermal decomposition and oxidation. An analysis of the component composition of modern lubricants is carried out, including base oils (mineral, synthetic esters, aqueous emulsions) and packages of anti-wear (AW) and extreme pressure (EP) additives based on chlorine, sulfur, and phosphorus. It is shown that synthetic esters are the most effective, characterized by high polarity, which ensures strong adhesion to metal, and increased thermo-oxidative stability. A set of methods is used for the objective assessment of lubricant properties: tribometric testing on a four-ball machine (determination of wear index, seizure load, and weld load) and analysis of thermal stability by differential scanning calorimetry (DSC) and thermogravimetry (TG). Using specific lubricants ("Politren HP-16", "Multidraw AL WM") as examples, their critical temperature thresholds, which determine suitability for high-speed calibration, are demonstrated.
Keywords:
calibrated rolled products, drawing, shot blasting, liquid drawing lubricants, tribological characteristics, thermo-oxidative stability, anti-wear additives, extreme pressure additives, differential scanning calorimetry, thermogravimetry