The stress state of the wire drawing is the three-way principal stress state of the two-way compressive stress and the one-way tensile stress. Compared with the three-way principal stress state where the compression stress is the compressive stress, the drawn wire is easier to reach the plastic deformation state. The drawing deformation state is the three-way main deformation state of two-way compression deformation and one-way tensile deformation. This state is unfavorable for exerting the plasticity of the metal material, and surface defects are more likely to be generated and exposed. The amount of pass deformation in the wire drawing process is limited by its safety factor, and the smaller the amount of pass deformation, the more passes are drawn. Therefore, in the production of wire, multi-pass continuous high-speed drawing is often used.
According to the temperature of the metal at the time of drawing, drawing below the recrystallization temperature is cold drawing, drawing above the recrystallization temperature is hot drawing, and drawing above the room temperature below the recrystallization temperature is warm drawing. Cold drawing is the most common drawing method used in wire and wire production. During hot drawing, the metal wire should be heated before entering the die hole, which is mainly used for the drawing of high melting point metals such as tungsten and molybdenum. During warm drawing, the metal wire also needs to be heated to a specified temperature by a heater before entering the die hole for drawing. It is mainly used for drawing zinc wire and alloy wire that is difficult to deform such as high-speed steel wire and bearing steel wire. According to the number of molds that the wire passes simultaneously during the drawing process, the drawing through only one mold is a single-pass drawing, and the drawing that successively passes through several (2-25) molds is a multi-pass continuous drawing. The linear speed of single-pass drawing is low, and the productivity and labor productivity are low. It is often used for the drawing of large wire diameter, low plasticity and special-shaped wire and wire. The multi-pass drawing has high line speed, high degree of mechanization and automation, and high productivity and labor productivity. It is the main method of wire and wire production. It is divided into non-sliding continuous drawing and sliding continuous drawing. According to the state of lubricant used in drawing, wet drawing is used for liquid lubricant, and dry drawing is used for solid lubricant. According to the cross-sectional shape of the drawn metal wire, there are round wire drawing and irregular wire drawing. According to the pulling force acting on the pulled wire, there are positive pulling force and reverse pulling force. There are also special drawing, such as roll die drawing.
Under the action of drawing force, the wire rod or wire blank is pulled out from the die hole of the drawing die to produce the metal plastic processing process of small-section steel wire or non-ferrous metal wire. Wires of different cross-sectional shapes and sizes of various metals and alloys can be produced by drawing. The drawn wire has accurate dimensions and a smooth surface, and the drawing equipment and mold used are simple and easy to manufacture. Deformation index of the drawing process The cross-sectional area of the titanium wire decreases during the drawing process and the length increases. The cross-sectional area and length of the wire before and after drawing are F and L, respectively. The main index of drawing deformation is calculated by the following formula: Conditions for realizing the drawing process In the drawing process, the drawing stress acting on the drawing force per unit cross-sectional area of the drawn wire at the die exit. The wire subjected to cold drawing has obvious deformation hardening, and its yield limit s value is close to its strength limit b. In production, b value is often used instead of s, so the conditions for achieving the drawing process can also be expressed as the drawing process The safety factor K can also be expressed by the ratio of b to L. The safety factor K value in the drawing process is generally between 1.40 and 2.0, t; 1.40 indicates that the drawing stress L is too large, the metal wire after the die hole may continue to deform and appear to be thin or broken, and the drawing process is unstable K It shows that the drawing stress L is small, the amount of drawing deformation in each pass is too small, and the number of drawing passes increases. When drawing ultra-fine wire with a wire diameter of less than 0.05mm, it is difficult to pass through the die. In order to improve the stability of the drawing process, reduce the number of breaks and die passes, and improve the production efficiency of drawing, a safety factor K value greater than 2.0 can be used.
- Classification of titanium wire
Titanium can be divided into pure titanium and titanium alloys based on whether they contain alloy elements, and titanium alloys can be divided into α titanium alloys and near-α-type alloys, (α + β) -type alloys, and near-β-type alloys according to their composition and room temperature organization. Alloys and β-type alloys. According to the different properties of titanium and titanium alloys, wires with different requirements can be prepared. Titanium and titanium alloy wire products are generally hard (Y) and annealed (M).
- Application of titanium wire
Titanium and titanium alloys have good corrosion resistance, high specific strength, non-magnetic, high biocompatibility, low impedance to ultrasound, high sound transmission coefficient, hydrogen storage and good shape memory function. The excellent characteristics of important use value have produced important uses in many fields such as aerospace, petrochemical, medical and health, automotive, construction, and sports and leisure products. Titanium and titanium alloy wire, as an important variety of titanium material series, have made great progress in terms of output, specification and application. Titanium rods and titanium alloy materials, as the leader in metal materials, have a series of excellent properties that are unmatched by other metal materials. Therefore, they have developed rapidly in recent years and have been rapidly and widely used in high-tech fields such as aerospace and military industry. The United States, Russia, Japan, China and other countries all attach great importance to the research and development of titanium alloys, constantly develop new titanium alloy materials, and expand the application of titanium and titanium alloys. Due to the continuous deepening of research and the increase in product series, many titanium products, such as titanium wire, have also increasingly entered the field of various consumer products.