History of Science and Engineering Annotation << Back History of Welding Development: from Craft to Science Leontyeva E.Yu., Murugov D.A. By integrating historical facts of the development of physics and chemistry, empirical knowledge of the welding process, theoretical knowledge of the philosophy of science, the authors answer questions about how and when such an honorable craft as blacksmithing, which included casting, welding and forging, turned into a science. Welding is not an invention of modern mankind, but was discovered a long time ago and was used by ancient craftsmen for thousands of years. However, until the emergence and active development of science (17th – 19th centuries), no significantly new technologies that fundamentally changed the welding process were created. Empirical knowledge did not acquire other qualitative characteristics, did not become scientific knowledge about welding. For the emergence of scientific knowledge in its modern understanding, a number of external and internal factors are necessary: a certain level of development of mathematics and mathematical methods, developed theoretical natural science and experiment as its basis. Based on this, the authors provide an analysis of the key events and discoveries that influenced the emergence of welding as a science. The emphasis is placed both on the sequence of historical facts and on general scientific changes that allowed the craft to become a science. The welding process is a complex physical and chemical process; in matters of developing modern welding technologies, welding materials, power sources, etc., it is impossible to get by with knowledge "at your fingertips." Discoveries in fundamental sciences provided an essential explanation of the physical, mechanical and chemical properties of metals, formed an understanding of the deep foundations of thermal effects and stresses, since only when heated and melted, the metal is able to form a welded joint. Developed theoretical natural science, together with a powerful experimental base and constantly growing production needs, led to the fact that welding, as one of the types of ancient blacksmithing, has become a significant branch of modern science and an integral part of modern industrial production. Key words: craft, science, history of science, origin of welding, development of welding as a science. Keywords: craft, science, history of science, origin of welding, development of welding as a science. DOI: 10.25791/intstg.4.2025.1542 Pp. 32-40.