Embedding material impact on the physical and chemical properties of titanium tube casting quality

In recent years, with the introduction of National Laboratory " metal precision thermal processing ," a water-cooled copper crucible induction melting furnace , our group has invested major forces units alloy water-cooled copper crucible induction melting (IsM) thermodynamics and kinetics , and achieved some results. Now be summarized in order to communicate with readers , and jointly promote the development of titanium industry.
    The book is a national "Ninth Five " key books . This paper focuses on titanium melt composition, titanium foundry control of the main line , in theory, more in-depth analysis of the system ISM smelting process titanium alloy melt composition influence factors and the role of law in temperature, and several commonly used titanium alloy analyzed. The book is divided into eight chapters , of which the first chapter introduces the features and titanium smelting technology ; second, third and sixth chapters are discussed the impact of volatile behavior of titanium alloy melt titanium investment casting composition of alloying elements , interstitial elements in titanium melting body dissolved in class skull formation mechanism ; fourth and fifth chapters ISM titanium smelting process gives the temperature field numerical simulation model and process parameter optimization design ; Chapter VII of the smelting process ISM exists a theoretical risk analysis ; Chapter VIII describes some examples of titanium smelting .

The crystal structure of titanium

Titanium with two different allotropic forms, low (< 882.5 C) stable state for alpha and dense row of the six party system; high temperature stable state for beta type. Body centered cubic.

  The lattice parameter alpha -Ti, 25 DEG,Ca＝2.9503±0.0004Å，c＝4.6832
±0.0004Å，c / a=1.5873±0.0004. Because the ratio of c/a alpha -Ti less than ideal spherical 1.633 axle ratio, so ti is malleable metal. The impurities present alpha in -Ti have a significant impact on the lattice structure of trace oxygen, the presence of nitrogen makes lattice growth along the c axis, cause the increase of C value and a value, in fact almost does not change.

Clinical application hindering of pure titanium prosthesis

In the roasting temperature casting shrinkage crystal transition volume change larger material can compensate the pure titanium, but easy to molten titanium reacts, the fouling layer formation of thick, affect the physical and mechanical properties of titanium prosthesis.

  At present can not only solve the titanium restoration precision, but also can reduce the pollution of Titanium casting has not been reported buried materials package, so about titanium casting investment research and development work is still a hot spot.

  In addition, the current commercial better performance of several ti investments are expensive, the manufacturers instructions also require the use of casting system of the factory matching (Titanium alloy valve, titanium), this has to some extent increased titanium restoration cost, finally make titanium restorations be roughly the same price with the use of expensive metal material prices.

  This hinders widely used in clinical application of pure titanium prosthesis.

Titanium casting Condensing shrinkage

Although Japan through years of research, introduced the Titanium 
 -vest, Titanium-vest-D (Ohara Co.), Selevest-DM, Selevest-D (Center for rotating, the United States has Noyes Vinh phuc) Tycast Mold (Pentron Co.), Germany Tancovest (Bego Co.), Rematitan plus (Dentaurum Co.) and other commercial products, although all have their own advantages, but also the existence of their own shortcomings, such as the pollution layer too thick and lack of precision castings.

  Theory and molten titanium oxide was blunt in calcination temperature shape variables are not large, can not be compensated completely condensed shrinkage Titanium casting process

Precision casting of titanium denture

Titanium alloy valve resources in China ranks first in the world, for dental titanium denture to provide the most favorable conditions. Currently the most common titanium denture processing technology, is still using the method of precision casting, and PFM crown and bridge can be made into various bracket and titanium removable denture fixed denture base crown.

  However, molten titanium precision casting and oxygen, nitrogen, hydrogen and other elements, oxides, chlorides, fluorides are able to react strongly, resulting in Ti investments (mold material selection very difficult).

Titanium denture success

Gold titanium check valve is suitable for making dentures, but the price is expensive, difficult to widely used. Cobalt chromium, nickel chromium alloy although cheap, but because of containing Ni, Cr, Co and other harmful elements, so not ideal material for making dentures.

  Therefore, the developed countries from the 80's of the last century began to study the Titanium alloy valve restorations, both the processing technology of titanium teeth or with matching equipment, equipment, have made gratifying achievements.

Oral application of pure titanium and titanium alloys

With the progress of the society, more and more materials for oral shell making dentures, metal, plastic, composite resin, ceramic etc..

  The metal material used for making dentures are mainly co Cr alloy, Ni Cr alloy, near alloy, this year and the emergence of pure titanium and Titanium alloy valve.