Desalination industry, promote the development of titanium tube titanium standard parts

Increasingly serious global freshwater titanium pipe price resources crisis , many countries are promoting water conservation. And everyone agreed that desalination is the best way to solve the water shortage . Desalination technology now hold more than 100 countries and regions, and double-digit rate every year is increasing .

      In the next few years will be greater room for titanium spring wire development of desalination , our country is a world leader in this technology , has decades of accumulated experience of . Desalination equipment will be used to replace the original titanium alloys.

      China alone needed materials such as titanium tubes for desalination have a few tons. This will promote the development of China's industry is largely titanium tube . Currently on the market through sales of titanium tubes titanium wire price can also be understood.

Aluminum and gallium affect the performance of titanium

Aluminum and titanium, gallium can increase a + β / β transformation point . 10% aluminum phase transition point can be increased to about 1080 ℃. Gallium ability weaker . Aluminum titanium start improving recrystallization temperature of titanium alloys martensitic transformation start point (MS) is not affected. Excess aluminum and gallium in Ti3M generated based on the ordered phase a2 use temperature . Further , the aluminum present in the metastable β phase , phase to promote ω a phase transition ,titanium pipe thereby reducing the volume percentage of the time ω alloy phase.

Impact on the performance of aluminum and gallium , aluminum, titanium and gallium can improve the tensile strength at room temperature and high temperature has little effect on the high temperature plasticity. With increasing aluminum content of titanium - aluminum density and Poisson coefficient decreased linearly . Within the range of solubility , aluminum can effectively improve the elastic modulus of titanium , shear modulus, specific resistance and line expansion coefficient . When a2 phase, the emergence of a peak performance .

Titanium - appears to Ti3AL base of a2 ordered phase when the aluminum alloy , titanium alloy increases the tensile strength , ductility and toughness to deteriorate .titanium rod This ordered phase is often a similar role with Ti3AL resistant titanium alloys for high temperature Ti3Ga phase in phase .

Effect of heat treatment on the properties of β titanium plates

β stabilizing element more dissolved β titanium , and to decrease the lattice parameter β titanium . β stabilizing element are raised to make room temperature tensile strength of pure titanium , while reducing the plasticity index elongation .titanium rod General eutectoid elements larger than the role of isomorphic elements.
With molybdenum , vanadium , niobium , and chromium, manganese, iron , cobalt, titanium impact of nickel on the elastic modulus and shear modulus of the crystalline elements eutectoid elements. In the quenched state , the peak value of the curve caused by the hardening phase ω . It makes elastic modulus, shear modulus and strength increases , the plastic lower .

Eutectoid β stabilizing element after adding titanium compound phase formed under certain conditions . However, the elements added slowly titanium eutectoid , compound phase is difficult to occur . Such as titanium - chromium system , TiCr2 often after long time to appear . In the system of analysis of the titanium element and the fast , sub-eutectoid alloy composition can be produced by the decomposition of the supersaturated phase a small amount of compound precipitated from the dispersion strengthening effect .

Improve β stabilizing element content , can keep more of β -phase alloys , can reduce sensitivity to hydrogen embrittlement . Further, in the two-phase alloy , the increase in the content of β stabilizing elements may also increase the hardenability of the alloy.

Mo can improve the thermal salt stress corrosion resistance of titanium alloys . Cobalt , palladium,titanium stockists molybdenum and niobium titanium in reducing medium can improve the corrosion resistance.
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How to medical titanium plates in the real sea change in galvanic corrosion

Galvanic corrosion behavior of electrochemical measurement parameter is the open circuit potential and galvanic current characterization of the two materials in contact titanium wire. The so-called open-circuit potential refers to the two materials temporarily off the meter coupling circuit to the reference electrode corrosion potential of each material were measured in the time. Due to the different degrees of polarization after coupling of different materials, the potential to achieve the basic stability of the different time after disconnection. Usually 1-20 minutes, the potential is measured after the stable potential. With the development of corrosion, the surface state of the material is also changing, and while the potential changes caused by changes in the behavior of galvanic polarization, ie corrosion kinetics changes. So we can come to understand variation of galvanic corrosion over time and the different electrical characteristics even on the track by open circuit potential measurements.
In the study of galvanic corrosion of titanium alloy parts can, first to see the real potential of the sea from rot titanium and other alloys from a thermodynamic point of view - time curve. All of these materials in the electrical potential in the real sea change over time. Especially stainless steel potential fluctuations and changes not only with the titanium is opposite tendency. Potential of titanium in all 20 days are rapidly being shifted over time, moving a rate of 200-300mV, but instead of stainless steel 1Cr18Ni9Ti rapid negative shift, moving magnitude of approximately 250mV. Copper alloys in seawater more stable full-B30 small potential fluctuation is small, but the overall trend is also a potential positive shift.
Seen from the curve, titanium potential shifts and more stable, while the stainless steel potential negative shift over time, it seems that with the stainless steel in just three months time cause corrosion perforation are intrinsically linked. Gillber and potential shifts Hefny think titanium has excellent corrosion resistance is due to the success of dense stable raw surface mechanical damage have a strong self-healing ability of TiO2: passivation film. We titanium E-pH diagrams and literature reports of knowledge, titanium chloride medium when pH> 2 does not occur when the activation area. For natural seawater pH was neutral to slightly alkaline is completely consistent.
Even for galvanic corrosion characteristics between pairs of titanium and titanium and even copper alloy, stainless steel between our TA2/BT14, TA2/B30 and TA2/18-8-ss three typical galvanic be analysis.
Galvanic corrosion specimen dimensions are 100 × 50 × 2mm, even for each group of three pairs of parallel samples were taken, even on the area ratio of 1:1. 104 days of trial.
According TA2/BT14 coupling measured open circuit potential - time curve, and galvanic current - time curve. May know, the open circuit potential curve has been in almost two titanium overlapped. medical titanium plate This shows that the coupling due to the polarization of the potential difference between the reduced and even disappear, although their corrosion potential difference of up to 150mV, would not exist galvanic corrosion.
According TA2/B30 even on the open circuit potential - time curve, and galvanic current - time curve. After the coupling of these two materials, TA2 potential positive shift dramatically, and B30, but fluctuate within a certain range, and a significant galvanic current. Another case, the outer channel potential difference is small, the galvanic current is not large, but there is an increasing trend to increase with time. It seems that localized corrosion of stainless steel from corrosion perforation caused by aggravated galvanic effect, the galvanic current rapidly increases. Thus, when titanium or stainless steel in contact with the B30, when their anode area ratio increased, galvanic effects will also increase, resulting Laqne early work also shows that this view.