Which process involves joining materials by coalescence through heat or pressure?

The process of welding specifically involves joining materials, typically metals or thermoplastics, through coalescence, which is made possible by applying heat and/or pressure. In welding, the materials reach a molten state at the interface, allowing them to fuse together as they cool and solidify. This technique is fundamental in numerous industries, including construction, automotive, and manufacturing, due to its ability to create strong, durable joints.

Machining is focused on the removal of material to achieve desired shapes and sizes, while assembling involves combining different parts into a final product without necessarily altering the material properties as welding does. Casting refers to pouring molten material into a mold, which is a different process that does not involve coalescence through heat or pressure in the same way welding does. Each of these processes serves distinct functions, but welding is unique in its method of permanently joining materials through heat or pressure-induced coalescence.