A fundamental aspect of metal production involves the metal forming process, utilized to reshape metals without removing material or changing its mass. The goal of metal forming is to take a raw metal piece and mold, configure, and transform it through tension, compression, shearing, and pressure.
Since the dawn of the first industrial revolution, a variety of metal forming techniques have emerged. Metal forming typically begins with a sheet of plain flat metal subjected to various methods such as forging, rolling, extrusion, drawing, stamping, and other techniques. Each process is carefully crafted to produce sturdy metal products.
Metal forming comprises two primary methods: hot and cold. The cold process, also known as cold heading, occurs at or slightly above room temperature. This approach involves a series of steps that gradually shape the workpiece to the desired form using dies and hammers.
Die casting, a widely adopted method for shaping metals, entails heating metals to their melting point and pouring the molten metal into a mold. This technique is mainly utilized with non-ferrous metals like copper, aluminum, zinc, magnesium, lead, tin, or bronze. Die casting is renowned for its precision and ability to produce products and parts with extremely close tolerances.
The expanded metal process, a type of cold metal forming, involves stretching and pulling metal, puncturing it with a blade to create shapes and designs. This method is cost-effective and suitable for aluminum, various steel types, and copper. Post-processing, such as finishes and coatings, can be added for protection or aesthetic enhancement.
Forging, one of the oldest metal forming methods, subjects a sheet of metal to stress to induce deformation, altering the grain flow and causing it to conform to the shape of the forging die. Falling between cold and hot forging, this process may involve heating the metal to facilitate forging without melting it.
Grey iron casting, distinct from forging, has been practiced for centuries, characterized by the gray color resulting from its graphite content. Various methods, including sand casting, are employed in the production of grey iron castings.
Investment casting is a technique for producing multiple parts in one casting. It begins with creating a wax model of the part, which is converted into a mold and subsequently filled with molten metal to form the final part. Multiple molds are connected by a sprue, which is removed after the metal cools.
Metal spinning, a cold metal forming process, involves spinning a flat metal piece at high speed for shaping. Pressure is applied using various tools called spoons. The powder process of metal forming utilizes metal powder subjected to pressure in a die, causing particles to conform to the die’s shape. Sintering, heating just below the melting point, hardens the part and enhances its strength.
Roll forming, a cold process, guides a sheet of metal through rollers, gradually reshaping it into a uniform shape. This cost-effective method is applicable to metals like zinc, brass, steel, and aluminum.
Several other processes shape and form metals to produce common items like springs, wire forms, and wire mesh. These processes are predominantly cold forming, with some methods involving heating metals for increased pliability.
