Application of titanium in the chemical industry

Titanium used in petroleum, chemical and other sectors

Petrochemical reactors, pressure vessels, heat exchangers, separators, piping, distillation tower condenser lining and so on.
Chemical industry distillation columns, reactors, pressure vessels, heat exchangers, filters, measuring instruments, turbine blades, pumps, valves, pipes, chlor-alkali production electrodes, synthetic lining tower, other acid-resistant equipment lining.
Paper Industry blender, bleaching tower, heating bath, the reaction tower piping.
Bleacher continuous textile industry, a distillation column, the reaction vessel, a condenser, heat exchange tubes, centrifuge, spinneret, valves, pumps.
Metallurgical Industry steel getter alloy additives, superconducting alloy material, electrolytic high purity metal (e.g., sodium, nickel, cobalt) of the cathode plate and the plating bath and the like.
Desalination and power plant heat exchangers, condensers, water heaters, pipes, other contact with seawater equipment.
Naval vessels housing industry, decks, valves, wing, propeller boats, drive shaft, the steam engine, the deep submarine pressure tanks, development of marine equipment.
Other titanium industrial bar ultrahigh vacuum pumps, medical and orthopedic instruments, artificial joints, pharmaceutical and food industry equipment.
Second, the titanium in the aviation industry application specific strength of titanium and its alloys (important than strength) is high in the metal structure of the material, its strength steel equivalent, but its importance is only 57% of the steel. In addition, the heat resistance of titanium and its alloys are strong, in the atmosphere of 500 ℃ can still maintain good strength and stability, but also short-term operating temperature even higher. The aluminum 150 ℃, stainless steel at 310 ℃ to lose their mechanical properties. When the aircraft missiles, rocket-speed flight, the engine and the surface temperature is very high, aluminum was not competent, the application of titanium alloy is very appropriate. It is because when the titanium and its alloys have high strength, light weight, heat and strong overall excellent performance, aircraft used instead of other metals in it, not only to extend the service life of the aircraft, but also can reduce their weight, thus greatly improve its flight performance. Therefore, titanium is one of the aviation industry and the aerospace industry's most promising structural materials. Titanium and its alloys. Mach 2 aircraft that its engine with titanium increased, but also part of the body needs titanium. Greater than Mach 3.5 aircraft, the engine inlet temperature is very high, it is not a high impact strength, can withstand high pressure, anti-vibration. Therefore, titanium round bar and its alloys in rockets, missiles and spacecraft only for the manufacture of the engine casing and structural components, and for the manufacture of pressure vessels, such as high-pressure gas cylinders, cryogenic liquid fuel tanks. In addition, titanium and its alloys in nuclear reactors and weapons have military applications.

titanium round bar When the possibility of titanium welding

Titanium tube weld cracks and pores problems
Titanium tube weld crack problem
When the possibility of titanium welding, titanium round bar thermal cracking of welded joints is small, it is because few impurities in titanium and titanium alloys S, P, C , etc. , low melting point of S, P eutectic formed at the grain boundaries rarely generation, coupled with effective crystallization temperature range narrow, titanium and titanium alloy solidification when a small amount of shrinkage , weld metal does not produce heat cracks.
When titanium and titanium alloy welding, weld when an oxygen , nitrogen is high , the performance of the weld heat affected zone or become brittle in the larger weld stress, cold cracking occurs . Characterized by cracks in the weld called a few hours or even longer delay cracks. The study showed that the hydrogen diffusion welding process is the main cause of such cracks. Hydrogen in the welding process to a lower temperature by diffusion of the high temperature heat affected zone deep pool , the area increase the hydrogen content of the precipitates increased so that the amount of TiH2 , brittle heat affected zone is increased , the other due to volume expansion caused by precipitation of hydrides greater the stress , plus a hydrogen atom diffusion and aggregation to the high stress areas of the area, resulting in the formation of cracks . This delay prevents cracks approach is titanium industrial bar to reduce the welded joint main source of hydrogen .
Titanium tube weld porosity problems
When titanium pipe welding , porosity is often encountered a major problem. The root cause of the formation of pores is affected as a result of hydrogen .
Prevent blowholes process measures are:
1 ) in high purity argon welding , argon gas purity not less than 99.99%
2 ) the elimination of titanium tubes , oil and other oxide on the surface of titanium and titanium tubes eye organics . Can be cleaned with a chemical and mechanical methods.
3 ) subjected to the bath gas well , control the flow and the flow rate of argon gas , to prevent turbulence , impact protection.
4 ) Choose the appropriate welding process parameters, welding specification , increasing the residence titanium bar supplier time of deep pools to facilitate the use of air bubbles escape , which can effectively reduce porosity.

titanium axle casting and casting surface quality analysis

3 smelting , casting and casting surface quality analysis
3.1 Melting and casting
Because of the high melting point of titanium alloy , chemical activity , smelting and casting must be performed under vacuum or inert gas . The experiment used a water-cooled copper material titanium crucible vacuum induction melting and casting furnace , the main process parameters are shown in Table 3 . Using Ti-6Al-4V alloy , the cast as an aerospace components, size of 150mm × 100mm, thickness 2.5mm, shell preheat temperature 300 ℃, gravity casting , casting the shell intact, no cracks , clean up after the castings shown in Figure 3 .

Table 3 Parameters melting titanium major

Table3 Main melting parameters of Ti alloy

Before pouring the vacuum degree / mbar 1.6 × 10-2

Before pouring water temperature / ℃ 37

When pouring the titanium wire price current intensity / A 870

When pouring voltage / V 565

When pouring electric power / kW 496

Frequency / kHz 7.91

Figure 3 titanium castings

Fig 3. A casting of titanium alloy

3.2 casting surface quality analysis

Birds casting surface silvery white , casting a clear outline , no surface flow marks and cold shut . Surface roughness Ra6.3μm.

Casting the X ray diffraction analysis that the casting surface Ti, ZrO2 and Ti2O, causes Ti2O ZrO2 is at a high temperature Ti reaction occurs with the reaction equation is as follows :

ZrO2 + Ti = Zr + TiOx + Oy

Zr and O to the diffusion of titanium castings , constitute the reaction layer .

EPMA sectional view of the casting for the detection , measurement and distribution line section of the zirconium -plane distribution , the results shown in Figure 4 . The reaction of zirconium castings depth of 25 ~ 50μm.
Figure 4 Distribution of zirconium wire probe and the surface distribution of photographs (a) casting microstructure ; (b) line distribution ; (c) surface distribution
Fig.4 Distribution of Zr titanium rod stock (a) Microstructure; (b) Linear; (c) Planar
4 Conclusion
( 1) The main component of sand and zirconium dioxide powder as refractory organic zirconium sol as a binder , a kind of cost-effective suitable for titanium casting Casting Shell Technology .
( 2 ) a systematic study of the effects of powder -liquid ratio , calcination temperature, time, etc. microwave dewaxing process parameters on the coating properties and performance of the shell to determine the optimum process parameters.
( 3 ) the use of water-cooled copper crucible vacuum induction furnace casting out a complete and clear Spade aerospace castings dimensions of 150mm × 100mm, thickness of 2.5mm. Casting titanium sheet suppliers surface roughness Ra = 6.3μm, the thickness of the reaction layer is 25 ~ 50μm.