titanium wire price the domestic technology of cast titanium

How the development of titanium tube casting process 

  At present, the domestic technology of cast titanium tubes have carried out some research and development work has evolved from the initial simple graphite casting titanium wire price‍ process to the coexistence of multiple process steps, their level has been greatly improved. Casting titanium tube is quite extensive, almost all already known to use cast molding method. Recently, more widely used in the production process is machined graphite, graphite tamping precision investment casting and ceramic shell mold casting process. 

     Due to simplify the learning activity pure titanium wire‍ of titanium alloy tube has, making it the casting process is different from iron-and nickel-based alloy, and has many unique features, which is mainly manifested in the choice of mold material. Cast titanium tube holding type material used must have a high chemical stability, high thermal shock resistance, low moisture absorption capacity and low thermal resistance, complete with mold titanium alloys‍ material at these performance requirements are still being explored.

titanium wire price The mechanical properties are usually

Casting and mechanical properties of titanium plate deformation difference 

The mechanical properties are usually titanium wire price‍ cast titanium plates are below the performance of similar titanium plate deformation, especially in the plastic show more respect for the highlight, which is mainly due to the results of casting and casting defects organizational constraints, cast titanium alloy titanium alloys‍ plates smaller than the other properties of the cast alloy drops. 

     For example, the yield strength titanium alloy casting fell only 13%, while 60% ​​of the small decline in aluminum, steel declined by 25 percent, cast nickel-based alloys decreased by 17%, which illustrate the performance characteristics and deformation of pure titanium wire‍ cast titanium with titanium rivaling negative energy characteristics, and in some ways even more than the deformation properties of titanium, especially in fatigue performance.

tungsten wire Drums and surface tension of the melt is cast

How to measure the melt viscosity titanium plate 

Drums and surface tension of the melt is cast alloy titanium wire price‍ melt important physical properties, they are directly related to the melting conditions, but also decided plate fluid flow and an important factor in filling of titanium. 

     Viscosity of titanium former Soviet scholars have conducted a lot of research was, and that the new structure of the melt, whereas in the binary titanium plate, with the alloy to the transition from a single-phase region multiphase region, pure titanium wire‍ the viscosity increases several times. When the melt viscosity was measured using a titanium crucible twist method, the graphite material of the crucible, and the crucible was measured in the elastic suspension with the gold wire twisting motion. Since the graphite crucible materials contaminate the carbon component alloy, therefore measured viscosity values ​​will be affected, but by comparing different carbon titanium viscosity liquid at different temperatures, and extrapolated to determine the titanium alloys‍ titanium plate viscosity of the melt

grade 2 titanium wire pplication prospect titanium material

Titanium is first discovered by British scientists Geneigeer from ilmenite ore in 1791 , in 1795 the German chemist carat Plott also discovered the element from rutile and named "Titanium ." Due to the high chemical activity of titanium , in 1910 it was discovered 120 years after it first extract the metal titanium , magnesium reduction method in 1940 had titanium sponge , from the foundation of industrial production methods titanium .

Titanium reserves in the crust is very rich , it is second only to iron, grade 1 titanium wire aluminum , magnesium, ranking fourth , more than ten times more than the sum of the common metals copper, nickel , lead and zinc. Industry for the production of titanium ore rutile , ilmenite and titanomagnetite .

Titanium metal has many excellent properties : Titanium accounted for 4.5g/cm3, only 56% of the ordinary structural steel , structural steel and strength quite ordinary or higher , the metal structure material , titanium is the highest strength .

The melting point of titanium 1668 ℃, than iron , nickel, slightly higher than aluminum , magnesium , high melting point above 1000 ℃ . Therefore, as the light metal structural materials , titanium has a much better than aluminum, magnesium alloy heat resistance , maximum temperature up to 600 ℃.

A titanium oxide layer with highly rugged surface oxide film formed in an oxidizing atmosphere , which is an oxidizing acid, alkali , salt medium , especially in wet chlorine and seawater , has excellent corrosion resistance.

Titanium has allotrope crystal structure above 885 ℃ of close-packed hexagonal lattice of β phase , the following α -phase body-centered cubic lattice . Therefore , after adding different alloying elements , titanium can be divided into α-, β- and α + β categories. Allotrope of titanium so that when adding different alloying elements can be very different performance alloys and heat treatment has a large effect .

Expansion coefficient of titanium is 8.2 × 10-6 / ℃, the smaller the general tungsten wire structure of the metal , the thermal shock when a small stress , suitable for use in temperature changing environment .

Titanium has good toughness and fatigue resistance , weldability is also very good . Good low temperature properties of titanium , at -196 ℃, low temperature brittleness is not presented , these properties are very suitable for structural use .

Thermal conductivity of titanium small , non-magnetic , superconducting properties also have some titanium , memory performance, and hydrogen storage properties and other functions.

Since titanium has a series of excellent performance, very rich in resources , after the advent of the industrial production of titanium , immediate attention by the world in general . 1947 United States take the lead in the industrialized production of titanium sponge , then produce two tons of titanium sponge , 1957 on the development of more than 15,000 tons . Japan in 1952, the former Soviet Union have begun in 1954 with an average annual production of titanium sponge . China also began trial production of titanium sponge in 1958, and now has formed a complete industrial system of titanium . Currently, there are countries in the world titanium industry mainly the United States , CIS, Japan, Britain, China and Germany.

The first is the application of titanium in military and aviation industry from the beginning . As early as 1951 the United States will be on the plane for titanium , used in aircraft to the United States in 1961 amounted to 3,940 tons of titanium manufacturing , accounting for 77% of the total amount of titanium , if the missile and space technology combined with titanium , titanium accounting 95% of the amount of material . The former Soviet Union , the United Kingdom titanium are mainly used in military and aerospace industries. In the 1970s , the excellent performance of titanium gradually generally recognized in civilian industry , titanium used in the metallurgical, chemical, electric power and other civilian industries increased year by year , the amount has been growing steadily . Now, the U.S. non- aerospace titanium has more than 30% , 50% CIS , Japan, due to historical reasons, almost all titanium for civilian industry.

China is a country very rich in titanium resources , after decades of development , titanium spring wire has been formed from titanium, titanium sponge , titanium and titanium smelting production , titanium equipment manufacturing as a whole industrial system. China titanium for the aerospace industry is also the rise of our country in the 1980s determined to promote the principle of civilian titanium , the state has taken a timely manner to support the policy , titanium industry was on the path of stable development. However, the current scale of production in China and titanium and titanium industry there is a great gap between the world's developed countries , in the civil industry is also a small amount of titanium , the reason is the superiority of titanium material has not been widely recognized , coupled with the high price of titanium material many companies can not afford to make a direct impact on the promotion of the use of titanium materials. For China 's titanium industry has been rapid development , we must vigorously publicize and promote the use of titanium metal, titanium metal material so that the superiority and the use of titanium material can bring economic and social benefits are well known.

grade 2 titanium wire Research Investment casting with titanium

Research Investment casting with titanium oxide ceramic shell -shell technology for

Titanium Investment casting technology to meet the needs of the aerospace grade 1 titanium wire industry and developed , has been widely used in aerospace titanium titanium components and civilian structures manufacturing. Practice has proved that the titanium alloy precision casting technology has become almost no margin of several forming processes to obtain maximum effectiveness of a process [ 1-3] . With the extensive application of titanium castings , its increasingly stringent quality and usability requirements , in addition, the level of costs also limit its application prospects is an important indicator . Graphite was low cost but poor quality of the casting surface , and is not suitable for the production of thin-walled complex parts [ 4 ] , but with the surface layer of refractory metal or yttrium oxide surface layer ceramic shell can be cast out of high quality titanium castings, but the cost is very high [ 5,6 ] . For this study the low -cost , suitable for the production of complex thin-walled shell technology for a new type of titanium oxide ceramic Investment casting is .

1 Materials and experimental methods

1.1 The main system shell material

Mold material : the material properties of the selected mode is shown in Table 1. The main use of imported wax wax casting specifically for titanium , gate part is low cost, performance can meet the requirements of homemade wax , respectively, after pressing, welding synthetic wax module.

Table 1 titanium casting mold materials with tungsten wire properties

Table1 Waxes used for making shells

Performance of imported wax homemade wax

Dropping Point / ℃ 69 ~ 71 70.5

Freezing point / ℃ 58 ~ 59 60 ~ 62

Linear shrinkage / % 1.3 0.4 0.6

Penetration / 1/10mm 12 ~ 14 11

Zhao hardness 21.1 19

Tensile strength / MPa 3.69 2.91

Adhesive wetting angle / ° 89 ~ 92 79 ~ 82

Density / g/mm3 0.91 ~ 0.94 0.95 ~ 1

Ash / % < 0.01 0.05

The surface layer and the adjacent surface layer of slurry : The main components of zirconia refractories , size of 30μm or less. Organic zirconium sol as a binder , the size of the refractory rubber match should be 10 ~ 15nm.

The surface layer and the adjacent surface layer of sanding : the main component of the surface layer is made of zirconium dioxide sand , the size of 150 ~ 300μm. To reduce costs, the use of adjacent surface layer is mainly composed of ZrO2.SiO2 zircon sand . The results show that the diffusion of Si is not seen in the casting , it is feasible the use of zircon sand .

Back layer system shell material: silica sol as a binder , using Morley powder and sand as refractories.

1.2 system shell method

The order of addition batter followed binders , refractory powder , trace additives. Minor amounts of additives to improve the stability of the coating role is to improve the wettability of the material and the mold , etc., and to prevent drying of the surface layer after the return water soluble additive is selected micro- organic material can be removed during the calcination . Stir batter than 2h at room temperature ( about 20 ℃) ​​in the air , titanium spring wire after the return of 1h to use .

O face the same batter pulp and raw materials , the production process is the same, only slightly smaller concentrations . Slurry feed back order binders , refractory powder. Also need to continuously stirred slurry back more than 2h , after the return of before use. Depending on the size of the backing layer casting , painted hanging normally takes 4-9 layers.

Drying : Drying time the surface layer and the adjacent surface layer are 24h, the temperature is 20 ℃, relative humidity of not less than 60% , the drying time of the backing layer is not less than 4h, the same as other conditions and the surface layer .

grade 1 titanium wire powder -liquid ratio across the layer

Dewaxing process : the use of microwave dewaxing , the equipment used for the large cavity size , 1500W Adjustable microwave intensity.

Roasting process : After dewaxing gas shell fired at grade 1 titanium wire without protection roaster .

Optimization of two main parameters of the Shell Technology

In all system shell process parameters on shell quality and ultimately a greater impact on the quality of castings are: batter ingredients, namely powder -liquid ratio , dewaxing and roasting process parameters [ 7 ] , this research labs now there are devices on the above parameters in-depth study and optimize selection.

2.1 powder -liquid ratio across the layer of coating thickness and suspension rate impact

Table 2 powder-liquid ratio on the opposite layer coating thickness and coating suspension rates . The results show that the greater the surface pulp powder -liquid ratio , the greater the thickness of the surface coating , the coating suspension , the better. Generally believed that if the surface coating is too thin (<0.2mm), the shell will be affected by sanding the surface , the roughness increased. If the coating is too thick (> 0.6mm), the coating , poor mobility, easy accumulation , during the drying or firing cracks easily [ 7 ] , which in this study has also been confirmed in the present study therefore the powder in the liquid ratio should be controlled between 5.0:1 - 6.0:1 .

Table 2 in the powder -liquid ratio of coating performance

Table2 Effects of solid / liquid ratios on the properties of coating

4.0:1 5.0:1 5.5:1 powder -liquid ratio 6.0:1

Coating thickness / mm 0.11 0.25 0.36 0.65

Coating suspension rate / % 88.3 90.1 93.1 97.6

2.2 Effect of shell powder -liquid ratio and calcination temperature on the room temperature and high residual strength

Figure 1 shows the ratio of powder and liquid at room temperature and high temperature effect on residual strength . Strength of the sample is composed of five levels of plasma and surface sand composition , each drying 24h, continuous coating hanging , firing 4h. Flexural strength of the strength test .

Figure 1 power-liquid ratio of the residual strength of the opposite layer

Fig.1 Effects of S / L ratios on the remain flexural of

surface coats baked at different temperatures

The results showed that the powder -liquid ratio improved shell tungsten wire specimen bending strength . Calcination temperature is increased , the flexural strength increases with . Since 1100 ℃ ZrO2 occurs near the phase transition , so that the strength in the vicinity of this temperature increase is not significant , but the phase change process , the lattice of unstable energy increased activity increased , so should be avoided in the actual production of the calcined temperature. After calcination at 1200 ℃ by the high ratio of powder and liquid coatings ( 6.5:1 ) intensity decreased slightly reason: Because the coating is too thick , a slight increase in the calcination process of internal defects , thereby affecting its strength. From the results in Table 2 and Figure 1 show that the optimum value of 5.5:1 powder-liquid ratio of the surface layer material . The firing temperature is preferably at about 1200 ℃, but for small pieces of calcination temperature can be set at around 1000 ~ 1050 ℃.

2.3 Optimization of process parameters dewaxing

For this study cast casting spade 150mm × 100mm , thickness of 2.5mm, the microwave dewaxing process, the time relationship between the intensity of the microwave shown in Figure 2 and dewaxing .

Figure 2 microwave intensity and dewaxing time

(a) the inner surface intact ; (b) inner surface microcracks

Fig.2 Effects of different microwave intensities on dewaxing time

(a) no crack; (b) have cracks

Figure in a district that is less than 70% when the microwave intensity , dewaxed shell inner surface smooth , with little residual wax, no visible cracks. When the microwave intensity is too large (b zone ) , dewaxed shell intact , although overall , but there are a few cracks in the surface layer , with the microwave intensity increased the number of cracks increases , the reasons for this phenomenon may be due to over- heating rate fast , since the internal stress of the inner and outer layers of different thermal expansion coefficients of the time to produce slack . Therefore microwave intensity used in this study was 50% , dewaxing time about 8min. Through other experiments show that this dewaxing process useful in the present study not only the spade member is equally applicable to other shapes and sizes of parts.

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 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 current intensity / A 870

When pouring voltage / V 565

When poring 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 titanium spring wire photographs (a) casting microstructure ; (b) line distribution ; (c) surface distribution

Fig.4 Distribution of Zr (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 surface roughness Ra = 6.3μm, the thickness of the reaction layer is 25 ~ 50μm.

titanium spring wire Now water is pumped been successful

Memory alloys in medical applications is also very compelling. E.g., the bone with the bone plate , not only can two fixing broken bones , and the recovery of the original shape of the compression force is generated , forcing the broken bones are joined together . titanium spring wire After straightening teeth using dental wire , long clip ligation of cerebral aneurysms and vas deferens , with the support plate straightening the spine , are implanted in the human body temperature by the action starts, thrombus filter is also a new product memory alloy . After being straightened filter implanted vein , will be gradually restored into a network , thereby preventing clot 95% flow to the heart and lungs.
Artificial heart is a more complex structure of the organ , muscle fibers of the elastic memory alloy thin film made ​​of ventricular cooperate to mimic ventricular contraction . Now water is pumped been successful.
Since memory alloy is a " life has alloy " , use it at a certain temperature changes shape , you can design all kinds of self-control devices , its use is expanding . The first application of shape memory alloy pipe fittings in and fasteners . A shape memory alloy is processed into an outer diameter smaller than the internal diameter of the pipe to be connected to the casing 4% , at liquid nitrogen temperature and then expanding the sleeve diameter of about 8% , this will be removed from the cannula assembly when the liquid nitrogen , the desire inserted from both ends of the tube connection . When the temperature was raised to room temperature , i.e., the sleeve forming a holding seal shrinkage . This connection can be in close contact with anti-leakage , far better than welding , especially suitable for aviation, aerospace , nuclear industry and submarine pipelines and other dangerous situations. The most promising application memory alloys in aerospace technology . July 20, 1969 , "Apollo" 11 lunar module landed on the moon , titanium wire manufacturers the first human landing on the moon to achieve the dream of traveling . After the astronauts landing on the moon , on the moon a few meters in diameter placed a large hemispherical antenna for transmitting and receiving information to Earth . A few meters from a large antenna mounted on the tiny lunar module sent into space inside . Antenna that was just invented near memory alloy used. Under normal circumstances, the first predetermined requirements of good memory alloy material with a very thin , then lower the temperature to press it into a ball , bring the day to go into the lunar module . Into the lunar surface after the temperature rise in the sunlight , when it reaches the transition temperature , antennas and " mind" from their original appearance , becomes a huge domed . At present, the shape memory effect and superelasticity has been widely used in various fields of medicine and life . Thrombus filter manufacturing , spinal orthopedic rods, plates , artificial joints, women bra , pure titanium wire artificial heart and so on. Can also be widely used in a variety of automatic regulation and control devices. Shape memory films and filaments may be the ideal material for future ultra- miniature robots and robots. Especially its light weight, high strength and corrosion resistance makes it highly popular in various fields .