Grinding treatment process titanium and titanium alloys are divided into : mechanical polishing , ultrasonic grinding, mechanical composite electrolytic polishing , grinding barrels .
A mechanical polishing : high chemical reactivity of titanium , low thermal conductivity, viscous , abrasive grinding machinery ratio is low, and easy to react abrasives , not for ordinary abrasive grinding and polishing of titanium , preferably good thermal conductivity superhard abrasives, such as diamond , cubic boron nitride , polishing line speed is generally 900 ~ 1800m/min appropriate, otherwise , the titanium surface grinding burns easily and micro- cracks .
Two ultrasonic grinding :titanium strip by ultrasonic vibrations , so that the surface to be polished and the abrasive grinding between the polished surface and the relative movement is to achieve grinding and polishing purposes. The advantage is that the polishing tool than the conventional rotary groove portion becomes easier to nest and narrow , but also a large grinding effect is not satisfactory castings .
3 Electrochemical Mechanical grinding : the use of conductive abrasive , electrolyte and a voltage is applied between the grinding and polishing the surface , the joint action by mechanical and electrochemical polishing , reducing the surface roughness to improve the surface gloss. The electrolyte was 0.9NaCl, voltage is 5V, speed 3000rpm/min, this method can only be grinding plane , polishing complex denture is still in the research stage.
4 barrels of grinding : the use of centrifugal barrel polishing generated revolution and rotation , so that the barrel of the denture and abrasive friction relative movement serve to reduce the surface roughness of the grinding purposes. Polishing automation, high efficiency, but can only reduce the surface roughness to improve the surface gloss medical titanium bars, poor precision grinding , deburring available denture fine and coarse grinding and before polishing .
tupian
2013年12月30日星期一
2013年12月29日星期日
The role of aluminum and gallium in titanium bar and titanium alloys in
Aluminum and gallium are titanium with a titanium and β form substitutional solid solution, mainly from the solid solution strengthening effect . The standard rule of titanium , industrial pure titanium in addition , almost all contain a certain amount of aluminum.
A2 relative to control due to the occurrence embrittlement , aluminum and other elements considered with the precipitation of a2 , the concept of aluminum equivalent . In a titanium alloy ,tittanium bar the aluminum equivalent of the following relationship :
AL `= AL +1 / 3Sn +1 / 6Zr +10 O` ≤ 8
Wherein , AL ` aluminum equivalent , AL, Sn, Zr weight percentage of these elements are in the alloy . O ` elements affecting the gap , also called oxygen equivalent . Oxygen equivalent to :
O `= O + C +2 N
Where O, C and N are both of these elements in the weight percentage of titanium . When adding titanium silicon , aluminum equivalent should be:
AL `= AL +1 / 3Sn +1 / 6Zr +4 Si ≤ 8
In the practical application of these formulas have some effect.
In the heat treatable alloys β , in order to prevent the produce ω phase metastable β phase decomposition when caused by brittle , you need a certain amount of aluminum , usually around 3%.
Adding aluminum in titanium alloys can be formed by the middle of alloys with high melting point metal to prevent intolerable metallic inclusions , the ingot ingredients evenly.titanium pipe If 78% Mo Mo - aluminum master alloy melting point of molybdenum can be reduced to about 1900 ℃.
There are currently being developed to Ti3AL and TiAL new high-temperature titanium alloy as the base , but the actual industrial production from a certain distance .
A2 relative to control due to the occurrence embrittlement , aluminum and other elements considered with the precipitation of a2 , the concept of aluminum equivalent . In a titanium alloy ,tittanium bar the aluminum equivalent of the following relationship :
AL `= AL +1 / 3Sn +1 / 6Zr +10 O` ≤ 8
Wherein , AL ` aluminum equivalent , AL, Sn, Zr weight percentage of these elements are in the alloy . O ` elements affecting the gap , also called oxygen equivalent . Oxygen equivalent to :
O `= O + C +2 N
Where O, C and N are both of these elements in the weight percentage of titanium . When adding titanium silicon , aluminum equivalent should be:
AL `= AL +1 / 3Sn +1 / 6Zr +4 Si ≤ 8
In the practical application of these formulas have some effect.
In the heat treatable alloys β , in order to prevent the produce ω phase metastable β phase decomposition when caused by brittle , you need a certain amount of aluminum , usually around 3%.
Adding aluminum in titanium alloys can be formed by the middle of alloys with high melting point metal to prevent intolerable metallic inclusions , the ingot ingredients evenly.titanium pipe If 78% Mo Mo - aluminum master alloy melting point of molybdenum can be reduced to about 1900 ℃.
There are currently being developed to Ti3AL and TiAL new high-temperature titanium alloy as the base , but the actual industrial production from a certain distance .
2013年12月24日星期二
Common forms a stable element in titanium and titanium bar in
The main elements of a stable aluminum , gallium , germanium, lanthanum , cerium, neodymium and oxygen , carbon, nitrogen, boron , etc. Recently, some people think scandium and hafnium may also fall into this category . In the industrial application of the most widely used titanium alloy a stable element is aluminum. In recent years, in the development of nearly a gallium -based superalloy CKS growing importance titanium
standard parts. Therefore , there will be described focusing on the role of aluminum and gallium .
1 Ti - Al binary system
The maximum solubility of aluminum in β titanium appeared in 1460 ℃, about 30%. The maximum solubility of aluminum in a titanium appeared in 1080 ℃, about a 11%, 550 ℃ , the solubility of aluminum in a titanium is about 7.5%. There will be two compounds , r phase and a2 -phase general phase diagram . r is an ordered phase based compound TiAL , with a face -centered tetragonal ( almost tetragonal ) lattice ; a = 4.005 Å , c = 4.073 Å , c / a = 1.0162. a2 -phase compound is an ordered group of Ti2AL having a hexagonal lattice , a = 5.8730 Å , c = 4.6543 Å , c / a = 0.8047. a2 phase transition phase can come from the β.
2 titanium - gallium
Titanium - Titanium binary gallium , gallium β titanium solution temperature maximum occurs at about 1500 ℃, approximately 38% (30 atomic% ) . Gallium in a maximum solid titanium in 940 ℃ about 17% (13 atomic% ) . Solubility decreases as the temperature decreases . General a2 phase is the phase diagram for the orderly phase -based Ti3Ga titanium whole distributor.
1 Ti - Al binary system
The maximum solubility of aluminum in β titanium appeared in 1460 ℃, about 30%. The maximum solubility of aluminum in a titanium appeared in 1080 ℃, about a 11%, 550 ℃ , the solubility of aluminum in a titanium is about 7.5%. There will be two compounds , r phase and a2 -phase general phase diagram . r is an ordered phase based compound TiAL , with a face -centered tetragonal ( almost tetragonal ) lattice ; a = 4.005 Å , c = 4.073 Å , c / a = 1.0162. a2 -phase compound is an ordered group of Ti2AL having a hexagonal lattice , a = 5.8730 Å , c = 4.6543 Å , c / a = 0.8047. a2 phase transition phase can come from the β.
2 titanium - gallium
Titanium - Titanium binary gallium , gallium β titanium solution temperature maximum occurs at about 1500 ℃, approximately 38% (30 atomic% ) . Gallium in a maximum solid titanium in 940 ℃ about 17% (13 atomic% ) . Solubility decreases as the temperature decreases . General a2 phase is the phase diagram for the orderly phase -based Ti3Ga titanium whole distributor.
2013年12月23日星期一
and the role of a β elements of titanium and titanium bar
Titanium is a very active metal element , and the effect of a number of elements which can occur, but can affect the properties of titanium and titanium alloys and titanium only those continuous or discontinuous elements of the solid solution is formed .
Role 1.β stabilizing element in titanium and titanium alloys in
β stabilizing elements include titanium located on the right side of the periodic table almost all transition elements and IB elements , about 30 species. The only real common dozen . Wherein the isomorphous β stabilizing elements molybdenum , vanadium, tantalum titanium stockists, niobium, eutectoid β stabilizing elements iron, chromium, manganese, copper , cobalt, nickel, tungsten, palladium and hydrogen. The unique role of hydrogen on titanium alloy will be described in relation to the impact of interstitial elements in titanium .
2.a role in stabilizing element in titanium and titanium alloys
The main elements of a stable aluminum , gallium , germanium, lanthanum , cerium, neodymium and oxygen , carbon, nitrogen, boron , etc. Titanium and titanium alloys in the industry 's most widely used is aluminum a stable element . Titanium aluminum can improve the tensile strength at room temperature and high temperature , high temperature has little effect on plasticity . Within the range of solubility , aluminum can effectively improve the elastic modulus of titanium , shear modulus,titanium sheet specific resistance and line expansion coefficient .
Role 1.β stabilizing element in titanium and titanium alloys in
β stabilizing elements include titanium located on the right side of the periodic table almost all transition elements and IB elements , about 30 species. The only real common dozen . Wherein the isomorphous β stabilizing elements molybdenum , vanadium, tantalum titanium stockists, niobium, eutectoid β stabilizing elements iron, chromium, manganese, copper , cobalt, nickel, tungsten, palladium and hydrogen. The unique role of hydrogen on titanium alloy will be described in relation to the impact of interstitial elements in titanium .
2.a role in stabilizing element in titanium and titanium alloys
The main elements of a stable aluminum , gallium , germanium, lanthanum , cerium, neodymium and oxygen , carbon, nitrogen, boron , etc. Titanium and titanium alloys in the industry 's most widely used is aluminum a stable element . Titanium aluminum can improve the tensile strength at room temperature and high temperature , high temperature has little effect on plasticity . Within the range of solubility , aluminum can effectively improve the elastic modulus of titanium , shear modulus,titanium sheet specific resistance and line expansion coefficient .
2013年12月18日星期三
Effect of heat titanium bar on β titanium organization
β stabilizing element are different degree of reduction of titanium a + β / β transformation point and sequentially tantalum, niobium, molybdenum, vanadium, silicon, copper , chromium, manganese, iron incremented.
β stabilizing element are reduced titanium martensitic transformation start temperature. β stabilizing element is gradually increased , the point M can be reduced to titanium room temperature , the β -phase titanium alloy when rapidly cooled to room temperature region can be retained to a high temperature β -phase temperature . At this point the content of titanium element is critical concentration . titanium standard part Clearly, the critical concentration is the ability of β -phase stability of a measure of alloying elements. Β -stabilizing element Ti alloy phase is based tantalum, niobium, vanadium, tungsten, copper , molybdenum , nickel, cobalt, chromium, manganese , iron in increasing order . Isomorphous β stabilizing element element is weak , the eutectoid type element is stronger .
Titanium Titanium elements on recrystallization temperatures. Except cobalt and niobium , the manganese, iron , titanium vanadium were increased recrystallization temperature.
With the increase of β stabilizing element content , when the alloy rapidly cooled from β -phase region will appear different organizational changes , β stabilizing elements will affect the decomposition of metastable β phase in the aging process , and to type "C" curve to the right goes .
Eutectoid binary β stabilizing element in the form of titanium , there are eutectoid transformation equilibrium phase at room temperature with compounds ( except for tungsten outside ) . With the lower eutectoid reaction temperature , its ability to stabilize β phase is larger, the worse the eutectoid transformation of the active compound of the more difficult the phase appeared . Iron, manganese , tittanium bar chromium and other elements in the analysis of β -phase component that has been retained to room temperature, and generally can not be eutectoid transformation occurs . But like silicon , copper, nickel and other fast -eutectoid elements are not, they are prone to change and generate eutectoid pearlite lamellar organization a + compounds.
β stabilizing element are reduced titanium martensitic transformation start temperature. β stabilizing element is gradually increased , the point M can be reduced to titanium room temperature , the β -phase titanium alloy when rapidly cooled to room temperature region can be retained to a high temperature β -phase temperature . At this point the content of titanium element is critical concentration . titanium standard part Clearly, the critical concentration is the ability of β -phase stability of a measure of alloying elements. Β -stabilizing element Ti alloy phase is based tantalum, niobium, vanadium, tungsten, copper , molybdenum , nickel, cobalt, chromium, manganese , iron in increasing order . Isomorphous β stabilizing element element is weak , the eutectoid type element is stronger .
Titanium Titanium elements on recrystallization temperatures. Except cobalt and niobium , the manganese, iron , titanium vanadium were increased recrystallization temperature.
With the increase of β stabilizing element content , when the alloy rapidly cooled from β -phase region will appear different organizational changes , β stabilizing elements will affect the decomposition of metastable β phase in the aging process , and to type "C" curve to the right goes .
Eutectoid binary β stabilizing element in the form of titanium , there are eutectoid transformation equilibrium phase at room temperature with compounds ( except for tungsten outside ) . With the lower eutectoid reaction temperature , its ability to stabilize β phase is larger, the worse the eutectoid transformation of the active compound of the more difficult the phase appeared . Iron, manganese , tittanium bar chromium and other elements in the analysis of β -phase component that has been retained to room temperature, and generally can not be eutectoid transformation occurs . But like silicon , copper, nickel and other fast -eutectoid elements are not, they are prone to change and generate eutectoid pearlite lamellar organization a + compounds.
Titanium bar products are resistant to corrosion characteristics
Titanium is a metal having a strong tendency to passivation , and oxidation in air or in a neutral aqueous solution can quickly generate a stable oxide layer of protective film , even if the film is destroyed for some reason , can be quickly restored automatically. Therefore, titanium has excellent corrosion resistance in oxidizing , neutral medium , made of titanium with titanium products also have strong corrosion resistance , widely used in the sealing surface material container equipment to address equipment sealing surface crevice corrosion problems.
Because of the great passivating titanium , in many cases, when in contact with dissimilar metals, corrosion is not accelerating , which may accelerate the corrosion of dissimilar metals .titanium standard parts When such a low concentration of non -oxidizing acids , if Pb, Sn, Cu or Ti alloy Monel galvanic contacts , the corrosion rate of these materials , and titanium is not affected. In the hydrochloric acid when contacted with a low Ti steel , the nascent hydrogen generated on the surface of titanium , titanium oxide film destruction , not only causes embrittlement of titanium , titanium and accelerate corrosion of titanium which may be due to a high degree of hydrogen active period.
Titanium iron content of certain media affect corrosion of iron in addition to the reasons for the increase in raw material reasons , often when soldering iron stain penetration weld , so that the local iron content increased weld , which when etching having a non-uniform properties. When using iron titanium support equipment, products made of iron and titanium contact surface iron contamination is almost inevitable in the region accelerated corrosion of iron contamination , especially in the presence of hydrogen . When the titanium oxide film surface contamination to mechanical damage , the infiltration of a metal hydroxide , based on the temperature , pressure, etc. , corresponding to the occurrence of hydrogen diffusion , which have different levels of the titanium embrittlement . Therefore, titanium and moderate temperature and moderate pressure hydrogen system used to avoid surface iron contamination.
In general , titanium pitting does not occur . Made of titanium products also has anti- corrosion fatigue stability.tittanium bar Crevice corrosion resistance of titanium is better, especially Ti-0.3Mo-0.8Ni and Ti-0.2Pd alloy , so Ti-0.3Mo-0.8Ni and Ti-0.2Pd widely used to make industrial products.
Because of the great passivating titanium , in many cases, when in contact with dissimilar metals, corrosion is not accelerating , which may accelerate the corrosion of dissimilar metals .titanium standard parts When such a low concentration of non -oxidizing acids , if Pb, Sn, Cu or Ti alloy Monel galvanic contacts , the corrosion rate of these materials , and titanium is not affected. In the hydrochloric acid when contacted with a low Ti steel , the nascent hydrogen generated on the surface of titanium , titanium oxide film destruction , not only causes embrittlement of titanium , titanium and accelerate corrosion of titanium which may be due to a high degree of hydrogen active period.
Titanium iron content of certain media affect corrosion of iron in addition to the reasons for the increase in raw material reasons , often when soldering iron stain penetration weld , so that the local iron content increased weld , which when etching having a non-uniform properties. When using iron titanium support equipment, products made of iron and titanium contact surface iron contamination is almost inevitable in the region accelerated corrosion of iron contamination , especially in the presence of hydrogen . When the titanium oxide film surface contamination to mechanical damage , the infiltration of a metal hydroxide , based on the temperature , pressure, etc. , corresponding to the occurrence of hydrogen diffusion , which have different levels of the titanium embrittlement . Therefore, titanium and moderate temperature and moderate pressure hydrogen system used to avoid surface iron contamination.
In general , titanium pitting does not occur . Made of titanium products also has anti- corrosion fatigue stability.tittanium bar Crevice corrosion resistance of titanium is better, especially Ti-0.3Mo-0.8Ni and Ti-0.2Pd alloy , so Ti-0.3Mo-0.8Ni and Ti-0.2Pd widely used to make industrial products.
2013年12月16日星期一
The role of hydrogen in the interstitial elements of titanium and titanium bar
Titanium and titanium alloys in the interstitial elements mainly of hydrogen , nitrogen , carbon, boron and hydrogen and silicon. Their impact on the titanium and titanium alloys have poor . Described herein will focus on the role of hydrogen, oxygen , nitrogen ,titanium whole
distributor carbon and boron.
The role of hydrogen in titanium and titanium alloys . In an industrial atmosphere , the maximum solid solubility of hydrogen in the β titanium is about 2.0% (49 atomic% ) . A titanium hydrogen of about 0.18% maximum solid (7.8 atomic% ) , in 319 ℃. This occurs at temperatures below the eutectoid transformation , its eutectoid point of approximately 1.62% ( 44% atom ) . β = a + γ
Eutectoid temperature of 281 ℃, hydrogen in the case of titanium the maximum solid solubility of a 0.13% (6.3 atomic% ) . γ phase is TiH2 compound having the face-centered cubic lattice , a = 4.44 Å . When the temperature dropped to a low 125 ℃, the solubility of hydrogen in a sharp decline titanium , about 0.001 to 0.0029% ( 0.05 to 0.14 atomic% ) . Should index, temperature and pressure in a hydrogen solubility in titanium and titanium- β by the solubility . Titanium and hydrogen interactions are reversible.
Hydrogen in titanium and titanium alloys in
Titanium and titanium alloys can cause hydrogen embrittlement various sources , causing low stress brittle fracture , therefore, can be used to prepare titanium and titanium alloy powder. Its approach is to titanium and titanium alloy materials ( such as chips , scrap , etc. ) in the 300 ~ 400 ℃ hydride embrittlement in a hydrogen atmosphere medical titanium plates, broken glass is made by milling the powder .
The role of hydrogen in titanium and titanium alloys . In an industrial atmosphere , the maximum solid solubility of hydrogen in the β titanium is about 2.0% (49 atomic% ) . A titanium hydrogen of about 0.18% maximum solid (7.8 atomic% ) , in 319 ℃. This occurs at temperatures below the eutectoid transformation , its eutectoid point of approximately 1.62% ( 44% atom ) . β = a + γ
Eutectoid temperature of 281 ℃, hydrogen in the case of titanium the maximum solid solubility of a 0.13% (6.3 atomic% ) . γ phase is TiH2 compound having the face-centered cubic lattice , a = 4.44 Å . When the temperature dropped to a low 125 ℃, the solubility of hydrogen in a sharp decline titanium , about 0.001 to 0.0029% ( 0.05 to 0.14 atomic% ) . Should index, temperature and pressure in a hydrogen solubility in titanium and titanium- β by the solubility . Titanium and hydrogen interactions are reversible.
Hydrogen in titanium and titanium alloys in
Titanium and titanium alloys can cause hydrogen embrittlement various sources , causing low stress brittle fracture , therefore, can be used to prepare titanium and titanium alloy powder. Its approach is to titanium and titanium alloy materials ( such as chips , scrap , etc. ) in the 300 ~ 400 ℃ hydride embrittlement in a hydrogen atmosphere medical titanium plates, broken glass is made by milling the powder .
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