Tungsten Wire Drawing Machine​

Tungsten has limited ductility at lower temperatures, and its fracture behavior is strongly affected by temperature, reduction per pass, die geometry, lubrication, back tension, and drawing speed. For this reason, hot drawing is commonly used during tungsten wire production, particularly when the wire still requires significant deformation. Correct temperature control helps maintain suitable deformation conditions and reduces the risk of brittle fracture.

Yes, but whether cold drawing is suitable depends on the tungsten grade, processing history, wire diameter, and required final properties. Tungsten wire production is not based on one fixed temperature from beginning to end. Drawing conditions can change as the wire becomes finer, and some production routes use lower temperatures in later drawing stages.

A large diameter reduction is normally divided into multiple drawing stages rather than completed in one step. As the wire becomes finer, the allowable reduction, drawing speed, tension, temperature, and die sequence must be adjusted more carefully. This staged approach makes it easier to control drawing stress and wire breakage when producing very fine tungsten wire.

Wire breakage is rarely caused by one parameter alone. Typical causes include unsuitable drawing temperature, excessive reduction per pass, incorrect die geometry, poor lubrication, excessive back tension, unstable drawing speed, and defects inherited from previous processing stages.

For tungsten in particular, fracture behavior is closely related to its microstructure and ductile-brittle transition behavior, so the drawing schedule must be matched to both the material and the required finished diameter.

Graphite is suitable for elevated-temperature drawing because it can provide lubrication under conditions where conventional low-temperature lubricants are unsuitable. In tungsten wire production, graphite-based suspensions can form a lubricating layer on the wire surface, reducing friction between the wire and die and helping limit die wear.

The lubricant condition is also important: insufficient lubrication can increase surface damage and friction, while excessive or poorly controlled coating can also affect drawing stability and finished wire condition.

No. The required temperature normally changes with wire diameter, tungsten grade, reduction schedule, and drawing stage. In some tungsten wire production routes, the heating temperature is progressively reduced as the wire diameter becomes smaller.

For this reason, the maximum furnace or die temperature shown in a machine specification should be understood as equipment capacity rather than the fixed production temperature for every wire size.

Reduction per pass directly affects drawing stress and the stress distribution inside the wire. When the wire diameter becomes very small, aggressive reduction can increase the risk of fracture and surface defects.

Ultra-fine wire therefore requires a carefully selected die sequence and reduction schedule rather than simply increasing the number of dies or running at the maximum machine speed.

Normally, such a large total reduction is divided into rough, fine, and micro drawing stages. Whether these stages are carried out on one machine or on separate machines depends on the required diameter range, drawing speed, heating arrangement, number of dies, and production route.

For a new line, it is better to define the complete diameter route first and then select the machine configuration for each stage.

No. The maximum mechanical speed of the machine is not necessarily the recommended production speed for every wire size.

As the wire becomes finer, drawing speed must be considered together with reduction per pass, temperature, lubrication, tension, die condition, and the required finished-wire quality. Ultra-fine wire generally requires more carefully adjusted drawing conditions than larger-diameter wire.

For machine selection, the most useful information is:

Tungsten grade · Inlet wire diameter · Required finished diameter · Existing drawing route · Required production speed · Bobbin size · Hot or cold drawing requirement

If an existing tungsten wire sample or current process specification is available, it can also be used to determine the drawing stages, heating arrangement, and machine configuration.