Drawing Methods for Shaped Wire: A Complete Classification of Profile Wire Production

The drawing production of shaped and profile wire mainly relies on different types of wire drawing machines. A combined drawing line typically integrates several functions — decoiling, pre-straightening, drawing, precision straightening, cut-to-length, feeding, polishing, and finished-product collection — and can process a wide range of cross-sections, including hexagonal, square, flat, round, and other custom profiles.

Based on process characteristics, the drawing production of shaped and profile wire can be classified as follows.

(1) By the temperature of the metal during drawing: drawing below the recrystallization temperature is cold drawing; above it is hot drawing; and drawing performed between room temperature and the recrystallization temperature is warm drawing. Cold drawing is by far the most widely used method in wire production. In hot drawing, the wire must be heated before entering the die, and it is mainly applied to high-melting-point metals such as tungsten and molybdenum. In warm drawing, the wire is also heated by a heater to a specified temperature range before entering the die; this method is mainly serves zinc wire and difficult-to-deform alloy wires such as high-speed steel wire and bearing steel wire.

(2) By the number of dies used simultaneously: drawing through a single die is single-pass drawing, while drawing consecutively through several dies (2–25) is multi-pass continuous drawing. Single-pass drawing has a lower line speed and is commonly used for large-diameter, low-ductility, and shaped wires. Multi-pass continuous drawing offers higher line speeds and greater productivity, making it the dominant method in wire production.

(3) By the state of the lubricant used: wet drawing uses a liquid lubricant, while dry drawing uses a solid lubricant.

(4) By the type of tensile force applied to the wire: forward-tension drawing, back-tension drawing, and vibratory drawing.

(5) By die type: fixed-die drawing, roller-die drawing, and others.

(6) By the number of wires drawn at the same time: single-wire drawing and multi-wire drawing. Single-wire drawing delivers high precision but lower efficiency; multi-wire drawing pulls many wires simultaneously on a multi-head drawing machine.