Titanium Wire

Titanium is a silver-white metal with many excellent properties. For example, the density of titanium is 4.54g/cm3, which is 43% lighter than steel, but its mechanical strength is similar to that of steel. And titanium is resistant to high temperatures and has a melting point of 1942K, which is nearly 500K higher than steel. In recent years, with the continuous research of titanium, more and more products made for titanium can be found in our daily life and titanium wires are one of them.

The Types of Titanium Wire
According to the different properties of titanium and titanium alloys, titanium wire with different requirements can be prepared, generally divided into pure titanium wire, titanium alloy wire, pure titanium glasses wire, titanium straight wire, titanium welding wire, titanium hanging wire, titanium coil wire, titanium bright wire, medical titanium wire, titanium nickel alloy wire, etc.

Different types of titanium wire have different uses. For example, pure titanium glasses wire is mainly used for making glasses holders, titanium hanging wire is used for hanging weight, and titanium nickel alloy wire is commonly used as a memory alloy material.

The Applications Of Titanium Wire
Titanium wire also perfectly inherits the advantages of titanium and titanium alloys, with a series of excellent characteristics such as good corrosion resistance, high specific strength, non-magnetic, high biocompatibility, low impedance to ultrasound, and good shape memory function.

Therefore, titanium and titanium alloy wires are widely used in many fields such as the military industry, glasses, earrings, headwear, electroplating hangers, welding wires, aerospace, petrochemical, medical and health, automotive, construction, and sports and leisure products.

And in recent years, due to the continuous development of the titanium wire industry, the variety of titanium wire has become increasingly diverse, which makes titanium wire more and more widely used in high-performance industrial supplies and consumer products.

At present, more than 80% of titanium and titanium alloy wires are used as welding wires, such as welding of various titanium equipment, welding pipes, repair welding of turbine discs and blades of aircraft jet engines, and welding of casings.

Due to its excellent corrosion resistance, titanium wire has been widely used in chemical, pharmaceutical, papermaking, and other industries. It can be made into a mesh for seawater filter, purified water filter, chemical drug filter, etc.

Titanium and titanium alloy wires are also used to manufacture fasteners, load-bearing members, springs, etc. due to their good overall performance.

In the medical and health industry, due to their excellent biocompatibility, titanium and titanium alloy wires are used to manufacture medical devices, skull fixation, etc.

Some titanium alloy wires with shape memory function, such as titanium-nickel alloy wires, are used to make satellite antennas, shoulder pads for clothes, women's bras, and eyeglass frames.

In the electroplating and water treatment industries, titanium and titanium alloy wires are used to manufacture various electrodes.

The fabrication of titanium product forms into complex shapes is routine for many fabricators. These shops recognized long ago that titanium is not an exotic material requiring elaborate fabrication techniques. This article will discuss the creation of good welds and effective heat treatments of titanium.

Important differences between titanium and steel or nickel-base alloys need to be recognized. These are:
• Titanium's lower density.
• Titanium's lower modulus of elasticity.
• Titanium's higher melting point.
• Titanium's lower ductility.
• Titanium's propensity to gall.
• Titanium's sensitivity toward contamination during welding.

Compensation for these differences allows titanium to be fabricated using techniques similar to those with stainless steel or nickel-based alloys. This article deals with common operations used in fabricating titanium.

Work AreaAnchor
The fabrication of titanium demands attention to cleanliness. It is not uncommon for shops that handle several metals to isolate an area to be used especially for titanium. The area set aside for titanium should be free of air drafts, moisture, dust, grease, and other contaminants which might find their way into or onto the metal.

Welding TitaniumAnchor
Titanium and most titanium alloys are readily weldable, using several welding processes. Properly made welds in the as-welded condition are ductile and, in most environments, are as corrosion resistant as the base metal. Bad welds, on the other hand, might be embrittled and less corrosion-resistant compared to a base metal.

The techniques and equipment used in welding titanium are similar to those required for other high-performance materials, such as stainless steel or nickel-base alloys. Titanium, however, demands greater attention to cleanliness and to the use of auxiliary inert gas shielding than these materials. Molten titanium weld metal must be totally protected from contamination by air. Also, hot heat-affected zones and the root side of titanium welds must be shielded until temperatures drop below 800°F (427°C).

Titanium reacts readily with air, moisture, grease, dirt, refractories, and most other metals to form brittle compounds. The reaction of titanium with gases and fluxes makes common welding processes such as gas welding, shielded metal arc, flux cored arc, and submerged arc welding unsuitable. Likewise, welding titanium to most dissimilar metals is not feasible, because titanium forms brittle compounds with most other metals; however, titanium can be welded to zirconium, tantalum, and niobium.

In spite of the precautions, many fabricators are routinely and economically welding titanium, making sound, ductile welds at comparable rates to many other high-performance materials. One of the important benefits of welding the commercially pure grades of titanium is that they are over 99% pure titanium and there is no concern for segregation. The same is true of weld wire or rod in commercially pure grades.

Welding ProcessesAnchor
Titanium and its alloys are most often welded with the gas tungsten-arc (GTA or TIG) and gas metal-arc (GMA or MIG) welding processes. Resistance, plasma arc, electron beam and friction welding are also used on titanium to a limited extent. All of these processes offer advantages for specific situations. However, the following discussion will be concerned primarily with GTA and GMA welding. Many of the principles discussed are applicable to all processes.

Types of Welding: Gas Tungsten-Arc (GTA) and Gas Metal-Arc (GMA)
The GTA process can be used to make butt joints without filler metal in titanium base sheet of up to about 1/8-inch thickness. Heavier sections generally require the use of filler metal and grooved joints. Either the GTA or GMA welding process can be used, although GMA welding is more economical for sections heavier than about one-half inch. If the GTA process is used, care should be exercised to prevent contact of the tungsten electrode with the molten puddle, thereby preventing tungsten pickup.

Power SupplyAnchor
A conventional power supply, connected to D.C. straight polarity (DCSP), is used for GTA welding of titanium. Reverse polarity (DCRP) is used for GMA welding of titanium. A remote-controlled contactor allows the arc to be broken without removal of the torch from the cooling weld metal, thereby maintaining inert gas shielding. Foot-operated current and contactor control, high-frequency arc starting, and shielding gas timers are other desirable features.

Welding TorchAnchor
A water-cooled welding torch, equipped with a 3/4-inch ceramic cup and a gas lens, is recommended for GTA welding of titanium. A one-inch cup may be required for GMA welding. Thoriated tungsten electrodes (usually 2% thoria) are recommended for GTA welding of titanium. Pointed electrodes (end blunted) help to control arc characteristics. The smallest diameter electrode which can carry the required current should be used.

Inert Gas ShieldingAnchor
Protection needs to be provided to titanium weldments on cooling down to about 800°F (427°C) as well as to the molten weld puddle in order to prevent contamination by air. During GTA and GMA welding, argon or helium shielding gases of welding grade with dewpoint of -50°F (-46°C) or lower are used to provide the necessary protection. Separate gas supplies are needed for:
• Primary shielding of the molten weld puddle.
• Secondary shielding of cooling weld deposit and associated heat-affected zones.
• Backup shielding of the backside of weld and associated heat-affected zones.