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How to make titanium springs?

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How to make titanium springs?

  1. Why Choose titanium springs?

At present, there are two kinds of titanium alloy for spring, one is low-cost titanium alloy grade 5, the other is high-cost titanium alloy grade 19 (also known as beta-c or ti38644). They have low density (Grade 5 titanium alloy density 4.51g/cm3, grade 19 titanium alloy density 4.82g/cm3), high strength, corrosion resistance, and low shear modulus. Because of these excellent characteristics of titanium alloy, compared with steel spring of the same specification, titanium spring can be designed with smaller volume, lighter weight, longer life and better elasticity. So titanium spring is very popular among cycling enthusiasts, especially in cycling competitions, mountain bike downhill and other sports.

titanium springs
  1. Disadvantages of titanium springs

Although titanium spring has many incomparable advantages over steel, it also has its own disadvantages. The main disadvantage is that the cost is too high and many customers can’t accept it. There are many reasons for the high cost, including the following:

—Titanium is much more expensive than steel

—Titanium spring has more specifications and less quantity of single specifications, which leads to more material sizes, less quantity and high material cost

—The coiling process of spring is difficult and the yield is low

—Less single production batch

However, with the continuous maturity of production technology, the production cost of titanium spring continues to reduce, and customers will slowly accept the price of titanium spring.

  1. Production process of titanium spring for bicycle rear shock absorption

1) Spring design

According to the specification, model, color and material requirements of the shock absorber provided by the customer, the reasonable wire diameter, turns and free height of the spring are designed. According to the actual situation of raw materials, work out the production plan and construction period.

2) Production of raw materials

The reality of the titanium spring market is that there are many kinds and relatively few quantities, so in order to ensure the accuracy of each dimension of the spring, the titanium bars used in the spring are often of unusual dimensions, such as the diameter of 10.2mm, 10.7mm, etc., while the number of titanium bars with a single diameter is relatively small, which causes great trouble for us to make spring materials, and each link needs constant adjustment of the machine and production efficiency Low cost.

The material of bicycle rear shock absorption spring is generally titanium bar, and the key steps of making titanium bar for spring are heat treatment, grinding, polishing and flaw detection.

Heat treatment: the material heat treatment is generally solution or solution plus aging treatment, to ensure the strength and hardness of the material to be high, so as to ensure the high performance of the spring.

Grinding: the grinding process is to control the diameter tolerance of the material, so as to ensure the accuracy of the spring.

Polishing: the surface finish of the material has a great influence on the yield of the spring coiling process. Titanium bars with poor finish or surface defects are easy to break when the titanium spring is on coiling.

Ultrasonic flaw detection: all titanium bars for titanium spring must be subject to ultrasonic flaw detection, and can be produced only after confirming that there is no defect inside, so as to avoid fracture during coiling or actual riding.

In addition to process control, raw material selection often plays a decisive role. For example, the performance of titanium spring made of medical titanium alloy grade 5 and industrial titanium alloy grade 5 is different. Because the composition content of medical titanium alloy GR5 and industrial standard GR5 is slightly different, and the material performance is different, so choosing the appropriate titanium alloy has a great influence on the performance of titanium springs.

3) Titanium spring Coiling

Because we choose titanium straight bar instead of titanium coiled wire for spring production, we can only choose lathe and axis for titanium spring coiling. The experienced master should control the speed, pitch and turns of the spring to ensure that each spring is a high-precision titanium spring.

All springs are cold coiled, not hot coiled.

Check the surface of the coil spring for cracks. If cracks are found, the spring will be discarded.

Cut off the redundant material head at both ends of the spring, and pay attention not to touch the second circle when cutting.

titanium spring machine

4) Spring Two Ends Flat Grinding

The rear shock absorption titanium springs of bicycles are all ground parallel, which is often another key technology. As mentioned earlier, titanium springs have many specifications and few quantities. When choosing automatic grinding machine, titanium springs of the same size must be ground together. Therefore, titanium springs must be ground manually, and the flatness of manual grinding cannot reach the flatness of automatic grinding machine. Therefore, it is necessary to carry out continuous manual correction and improve the flatness of spring grinding.

5) Heat Treatment

The heat treatment of titanium spring is generally solution treatment plus aging treatment. Solution plus aging can make the strength and hardness of titanium spring reach a very high level, and ensure that titanium spring has a very high performance. Due to the memory of titanium, titanium spring will generate some deformation after heat treatment, such as size change, verticality change and so on. Therefore, subsequent manual correction must be carried out.

titanium spring heat treatment

6) Detection

After production, titanium spring must go through further processing and testing, including strong pressure processing, stiffness testing, stroke testing, fatigue life testing, etc., to ensure that the spring meets the requirements of customers.

titanium spring detection

7) Manual correction & dimensional inspection

After heat treatment, the size of the spring will change slightly, which must be corrected manually to ensure that the spring can meet the requirements of customers. In the process of manual correction, constantly check the size of the spring, and correct the unqualified spring again until the size is qualified.

8) Shot peening

Shot peening is a necessary surface treatment process for titanium spring. Shot peening can not only remove burrs and beautify the appearance, but also improve the surface hardness and further improve the performance of titanium spring.

titanium springs

9) Coloring for titanium springs

According to the requirements of different customers for titanium spring color, titanium spring can go through the following processes to make various colors

Anodizing: gold, blue, purple, green, black, rainbow

Vacuum coating or nitriding: gold, black,Oilslick and burnt color.

Red color by special coloring process.

10) Logo Eteching

We provide free logo and specification engraving services, according to the content of customer requirements, using laser marking method to carve the surface of titanium spring.

11) Packaging

Choose bubble paper or pearl cotton to wrap each spring to ensure that the surface of the spring will not be damaged during transportation.

How to reduce the price of titanium products such as titanium screw?

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Compared with the traditional steel screw and iron screw, titanium screw has great advantages in both performance and decoration. Of course, there must be some differences in price with so many advantages. Nevertheless, the demand for titanium screw in our life is irreplaceable.

I believe that everyone knows about the irreplaceability of titanium screw, but the price of titanium screw is also criticized by many people, so titanium screw manufacturers have been committed to how to reduce the price of titanium screw, and made a lot of efforts in this regard, the following simple from two aspects to understand the possible future titanium. The trend of screw price reduction.

In fact, if we want to reduce the price of titanium screw, we can say from two aspects. The first direction is to improve production capacity, optimize production process, invest in research and development funds, seek new technology in the production process of titanium screw, reform equipment, improve the efficiency of equipment, etc. The second direction is to reduce energy consumption, metalworking and so on. Energy consumption is very serious in the industrial production process, and energy is the cost. Reducing energy consumption is the cost reduction. Then the price of titanium screw can be reduced.

Therefore, in the future, if titanium screw manufacturers want to reduce the price of titanium screw, they must expand the production capacity of titanium screw and improve the production efficiency of titanium screw. For various types of titanium screw products, they must be more abundant, thus forming a relatively complete titanium metal processing system in China.

Titanium screw manufacturers reduce the price of titanium products such as titanium screw from two aspects

After all, in the future, titanium screw and related titanium products will inevitably lead to demand peaks, and all walks of life will inevitably rise to a higher level of equipment precision, so ordinary steel screw will not meet such high requirements, while titanium screw can, for example, fasteners used in mobile phones, must. However, it is necessary to use titanium screw fasteners, after all, the use of other metal fasteners will inevitably increase the weight of mobile phones, thereby affecting the feel.

How to reduce the price of titanium products such as titanium screw

What are the advantages of titanium alloy screw?

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  1. The specific strength (tensile strength/density) of titanium alloy screw is higher (see figure), and the tensile strength can reach 100-140 kgf/mm2, while the density is only 60% of that of steel.
  1. Medium temperature strength is good, the temperature is several Baidu higher than that of aluminium alloy, it can still adhere to the required strength at medium temperature, and can work for a long time at 450-500 C.
  1. Good corrosion resistance. Titanium in the atmosphere immediately forms a uniform and fine oxide film, which has the ability to resist the corrosion of various media. In general, titanium has excellent corrosion resistance in oxidizing and neutral media, especially in seawater, wet chlorine and chloride solutions. However, in reducing media such as hydrochloric acid solution, the corrosion resistance of titanium is poor.
  1. Titanium alloy screw has good low-temperature function, and titanium alloy with very low void elements, such as TA7, can still adhere to certain plasticity at – 253 C.
  1. Titanium alloy screw has low elastic modulus, low thermal conductivity and no ferromagnetism.
  1. Titanium alloy screw has high hardness.
  1. Poor stamping and excellent thermoplasticity.

Titanium alloy screw heat treated by adjusting the heat treatment process can obtain different phase composition and arrangement. It is generally believed that fine equiaxed arrangement has better plasticity, thermal stability and fatigue strength; needle arrangement has higher durability, creep strength and fracture toughness; equiaxed and needle mixed arrangement has better inductive function.

The commonly used heat treatment methods are annealing, solid solution and aging treatment. Annealing is to eliminate internal stress, improve plasticity and arrange stability, so as to achieve better inductive function. Generally, the annealing temperatures of alpha and (alpha+beta) alloys are 120-200 C below the change point of (alpha+beta) beta phase. Solid solution and aging treatment are rapid cooling from high temperature zone to obtain martensite alpha’-phase and metastable beta phase, and then the metastable phase is differentiated by holding in medium temperature zone to obtain fine dispersed second phase particles such as alpha phase or compound. To achieve the purpose of strengthening the alloy. The quenching of general (alpha+beta) alloys is carried out at 40-100 below the change point of (alpha+beta) beta phase, and the quenching of metastable beta alloys is carried out at 40-80 above the change point of (alpha+beta) beta phase. Aging treatment temperature is generally 450 – 550 C. In addition, in order to satisfy the special requirements of the workpiece, two-layer annealing, isothermal annealing, beta heat treatment, thermomechanical heat treatment and other metal heat treatment processes are also used in industry.

What are the advantages of titanium alloy screw

Application of Special Properties of Nickel-Titanium Alloys

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In addition to its basic properties, nickel-titanium alloys have special properties. Because of their special properties, nickel-titanium alloys have widened their applications. In general, the special properties of nickel-titanium alloys are as follows:

Shape memory characteristics: Shape memory is when the parent phase of a certain shape is cooled from above Af temperature to below Mf temperature to form martensite, the martensite is deformed below MF temperature, heated below Af temperature, accompanied by inverse phase transformation, the material will automatically restore its shape at the parent phase. In fact, shape memory effect is a heat-induced phase transition process in Ni-Ti alloy.

Superelasticity: The so-called superelasticity refers to the phenomenon that the strain produced by the specimen under external force is much larger than the elastic limit strain, and the strain can automatically recover when unloading. That is to say, in the parent phase state, stress-induced martensitic transformation occurs due to the effect of external stress, which results in the mechanical behavior of the alloy different from that of ordinary materials. Its elastic limit is far greater than that of ordinary materials, and Hooke’s law is no longer obeyed.

Corrosion resistance: Some studies show that the corrosion resistance of nickel-titanium wire is similar to that of stainless steel wire.

Sensitivity of temperature change in oral cavity: The orthodontic force of stainless steel wire and CoCr alloy orthodontic wire was not affected by temperature in oral cavity. The orthodontic force of hyperelastic nickel-titanium alloy orthodontic wire varies with the change of oral temperature. When the deformation is constant. The orthodontic force increased with the increase of temperature. On the one hand, it can accelerate the movement of teeth, because the temperature changes in the oral cavity will stimulate the blood flow in the blood stagnation area caused by the capillary arrest caused by the orthodontic device, so that the repaired cells can be fully nourished in the process of tooth movement and maintain their vitality and normal functions. On the other hand, orthodontists can not accurately control or measure the orthodontic force in the oral environment.

Anti-toxicity: Nickel-titanium shape memory alloy is a special chemical composition, that is, it is a nickel-titanium isoatomic alloy, containing about 50% of nickel, and nickel is known to have carcinogenic and carcinogenic effects. In general, the oxidation of titanium on the surface layer acts as a barrier, which makes the Ni-Ti alloy have good biocompatibility. TiXOy and TixNiOy in the surface layer can inhibit the release of Ni.

Soft orthodontic force: At present, commercial orthodontic wires include austenitic stainless steel wire, cobalt-chromium-nickel alloy wire, nickel-chromium alloy wire and titanium alloy wire. The load-displacement curves of these orthodontic wires under tension test and three-point bending test conditions are discussed. The unloading curve platform of Ni-Ti alloy is the lowest and the flattest, which indicates that it can provide the most durable and soft orthodontic force.

Good shock absorption characteristics: The greater the vibration caused by chewing and night molars to the archwire, the greater the damage to the root and periodontal tissue. The results of different archwire attenuation experiments show that the vibration amplitude of stainless steel wire is larger than that of superelastic nickel-titanium wire. The initial vibration amplitude of superelastic nickel-titanium archwire is only half of that of stainless steel wire. The good vibration and vibration reduction characteristics of archwire are very important for the health of teeth, while traditional archwire such as stainless steel wire can increase root absorption. Tendency.

Application of Special Properties of Nickel Titanium Alloys

Classification and Characteristics of Titanium and Titanium Alloys

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Titanium alloys are alloys based on titanium with other elements added. Titanium is the seventh most abundant metal in the earth’s crust, but it is difficult to extract titanium from its oxides.

Titanium and Titanium alloy detection

Classification of Titanium and Titanium Alloy

Alpha titanium alloy

The structure is stable, the wear resistance is higher than pure titanium, and the anti-oxidation ability is strong. Its strength and creep resistance are maintained at temperatures of 500 600 C, but it can not be strengthened by heat treatment, and its strength at room temperature is not high.

Near-alpha Titanium Alloy

Aluminum, tin, zirconium and a small amount of molybdenum, vanadium and manganese are the main stable elements in the composition. It has excellent creep resistance at high temperature, good thermal stability and welding performance. The long-term working temperature is 300 C. It is produced by vacuum consumable arc furnace.

Beta titanium alloy

Without heat treatment, the alloy has higher strength. After quenching and aging, the alloy is further strengthened, and the room temperature strength can reach 1372-1666 MPa. However, the thermal stability is poor, so it is not suitable for use at high temperature.

Alpha+beta titanium alloy

It is a dual-phase alloy with good comprehensive properties, good structural stability, good toughness, plasticity and high temperature deformation properties, and can be processed under hot pressure, quenched and aged to strengthen the alloy. After heat treatment, the strength increases by 50%-100% compared with annealing state, and the high temperature strength can work for a long time at the temperature of 400 500 and its thermal stability is inferior to that of alpha titanium alloy.

Characteristics of Titanium and Titanium Alloys

High cost, high specific strength

Titanium alloys can be divided into heat resistant alloys, high strength alloys, corrosion resistant alloys (Ti-Mo, Ti-Pd alloys, etc.), low temperature alloys and special functional alloys (Ti-Fe hydrogen storage materials and Ti-Ni memory alloys).

Low density and High strength

The density of titanium alloys is generally about 4.51g/cubic centimeter, which is only 60% of steel. Some high strength titanium alloys exceed the strength of many alloy structural steels. Therefore, the specific strength (strength/density) of titanium alloys is much greater than that of other metal structural materials, and parts with high strength, good rigidity and light weight can be produced.

High thermal strength

The required strength can be maintained at medium temperature, and the specific strength of these two kinds of titanium alloys can be maintained at 450 – 500 C for a long time. The working temperature of titanium alloy can reach 500 C, while that of aluminium alloy can be below 200 C.

Good cryogenic performance

Titanium alloy can maintain its mechanical properties at low and ultra-low temperatures. Titanium alloys with good Cryogenic Properties and very low interstitial elements, such as TA7, can maintain a certain degree of plasticity at – 253 C. Therefore, titanium alloy is also an important low temperature structural material.

Low thermal conductivity elasticity

The thermal conductivity of titanium is about 1/4 of nickel, 1/5 of iron and 1/14 of aluminium. The thermal conductivity of various titanium alloys is about 50% lower than that of titanium. The elastic modulus of titanium alloy is about 1/2 of that of steel, so its rigidity is poor and easy to deform. It is not suitable for making slender rods and thin-walled parts. The rebound of machined surface is about 2-3 times of that of stainless steel, which results in severe friction, adhesion and bond wear of tool flank.

High chemical activity

Titanium has high chemical activity and strong chemical reactions with O, N, H, CO, CO2, steam and ammonia in the atmosphere. Titanium has high chemical affinity and is easy to adhere to friction surfaces. Titanium or titanium alloys can be oxidized to form many beautiful colors (haircut scissors)

Technological characteristics

The common form of titanium alloy is mixing with aluminium and vanadium. This material has the characteristics of good malleability and low creep. The ductility of titanium alloy is limited – the bending radius of thin plate is more than 1.5 times of the thickness. It can be welded, but it is difficult, but easy to diffuse bonding.

Shortcoming

Titanium alloys are very expensive. As a result, they were initially mostly used in aircraft structures, aircraft, and high-tech industries such as petroleum and chemical industries. There are also some Titanium alloys for people’s livelihood, but the prices of these products are still high, mostly belong to high-priced products.

Main Applications of Titanium Alloys

Aerospace

Most of the SR-71 fuselage is titanium, which was obtained from the Soviet Union at the height of the Cold War. Lockheed used various possible camouflage methods to prevent the Soviet government from knowing the uses of the titanium. To reduce costs, they use titanium alloys that are softer and easier to process at lower temperatures. The finished aircraft is painted dark blue (approaching black) to enhance the camouflage effect of thermal radiation cooling and high altitude.

Medical care

Titanium and titanium alloy materials can be processed as human implants. The elastic modulus of titanium alloy is similar to that of human skeleton, and the compatibility of titanium alloy is good. The surface of titanium alloy implanted into human body needs to be oxidized. After treatment, honeycomb holes will form on the surface, so honeycomb holes on the surface are conducive to cell growth and bonding. And there is no toxicity and other effects. The corrosion resistance of titanium alloy is very strong. The acid-base value of human body varies from time to time, and the corrosion resistance of titanium alloy is very good.

Application of Titanium Spring in Automobile

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With the popularization of titanium materials, the products of titanium products are more and more popular. Titanium spring has high elasticity, high strength and high plasticity, and has better fatigue resistance than steel spring. Titanium alloy is an ideal spring material because of its high specific strength and low elastic modulus. Compared with steel spring, titanium spring has the advantages of light weight, small volume and high resonance frequency. Its density and elastic modulus are only half of that of steel spring, and its strength is almost the same as steel spring. Because of these characteristics, titanium spring can be designed with smaller diameter and fewer circles than steel spring in practical application. As far as springs are concerned, high strength is the most important performance requirement for materials, so high strength beta titanium alloys, such as Ti-3Al-8V-6Cr-4Mo-4Zr and Timetal LCB (Ti-6.8Mo-4.5Fe-1.5Al) alloys, are the best choice for manufacturing springs. A titanium spring is 3.06 kg lighter than the corresponding steel spring. For the four supporting springs in automobiles, the weight can be reduced by about 12 kg. Replacing steel spring with titanium spring can easily solve the problem of too long and too big diameter of steel spring, which has been puzzling designers for a long time. Moreover, because titanium alloy has excellent corrosion resistance, the coating can be cancelled and the weight can be further reduced. Titanium springs have been used in some sports cars. For example, Timetal LCB springs have been used in Ford Simon & Simon racing cars for more than two years, reducing the weight by about 36 kg.

automobile titanium shock spring made from Ti-3Al-8V-6Cr-4Mo-4Zr

Application of Titanium Metal in Sports Goods

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The application of metal titanium in sports goods, from the earliest tennis racket, badminton racket to golf head, handle and racing car widely used in recent years, has greatly improved people’s understanding of titanium.

  1. Golf clubs, ball heads

Titanium golf clubs and ball heads are still the pillars of Titanium application in the civil field. It seems that all the manufacturers in the world have produced golf clubs and ball heads. Golf players always want to play with bigger clubs. Titanium has a small proportion and a high strength. It can make the ball head bigger without increasing the total weight of the club. In a wide range of experiments, the hitting rate of golfers with titanium ball head is 20% higher than that with steel ball head, and the hitting distance is improved.

At present, the bigger golf head requires its surface to be very thin, so it needs surface material to be very durable. SP-700, a new type of titanium alloy developed by Japan Steel Pipe Company, has high strength and good formability. Recently, it has been used as the surface material of Taylor 300 Series Golf heads, and is a best-selling golf market.

Alloy Titanium golf clubs with high strength and low weight

  1. Tennis racket and badminton racket

At present, the application of titanium in tennis racket is mainly to bury pure titanium mesh into the racket frame. In this way, not only the instantaneous inertia force of the tennis racket is improved, but also it is easy to hit the ball out even if the ball does not hit the center of the racket, which enhances the batting force of the racket.

In recent years, the market demand of titanium tennis rackets in Japan has been on the rise. Almost all Japanese tennis racket manufacturers now sell titanium rackets, which account for about half of the racket market. In order to classify the rackets, each manufacturer produces rackets according to the characteristics of titanium. At the same time, titanium-nickel superelastic alloy material and coating process are also used in the handle part of the rackets, so as to develop new uses of titanium.

Recently, the use of titanium resilience to enhance the batting effect has attracted much attention. Some Japanese companies are currently developing new titanium fibers for tennis rackets. The alloy is a shape memory alloy with superelastic function. Even if it is deformed under load, the original shape will be restored immediately after the external force is eliminated. When the material is embedded in the left and right sides of the racket handle, the rebound force can be obviously increased when the racket is hit.

And tennis racket-like, also developed the frame with pure titanium, long handle with Ti-3Al-2.5V badminton racket, and has been commercialized.

low weight and high stength titanium tennis racket

titanium badminton racket manufacturer

  1. Bicycles for Competition

The bicycle is manpower-driven because it needs to be very light, especially in racing cars considering race speed. If the weight of the car is reduced by one gram, one thousandth of a second can be gained. Normal bicycles use 36 strips, while titanium bicycles use 24 strips, which not only reduces the weight, but also reduces the wind resistance. Titanium and titanium alloys are first used in parts. Italian Campagnolo has used titanium and titanium alloys to manufacture various parts of bicycles for competitions, including encapsulating transmission pins, left-handed nuts, pinless crankshaft, front and rear hub axles, left and right pedal axles, etc.

Litespeed makes bicycle frames from titanium, which weigh an average of 2.5 pounds and cost $2,800 each. Titanium frame is lighter and more comfortable than chromium-molybdenum alloy frame, and its service life is longer. Over the past four years, industrial pure titanium tube frames made of Ti-3Al-2.5V (sport grade) titanium alloy for non-aviation use have been popular, with prices ranging from $1600 to $3500 for each pair and $2400 to $6000 for the entire bicycle. At present, nearly 50 companies produce titanium bicycles, and the United States is already the largest producer and consumer of titanium bicycles. Nowadays, bicycle sports are widely carried out all over the world. Titanium bicycles are especially suitable for the requirements of high-grade bicycle sports, so the sales of Titanium bicycles are gradually increasing.

low weight titanium racing bikes

  1. Competition vehicles

Because of its excellent physical and mechanical properties, titanium has been used in racing cars and limited production of bizarre sports vehicles. The application of titanium in automobile industry can greatly reduce the weight of automobile, reduce fuel consumption, protect environment and reduce noise. The characteristics of titanium material have been well reflected in the racing car.

Almost all the metal parts on automobiles can be made of titanium and titanium alloys, such as bolts, connecting rods, rockers, buffer rear brackets, exhaust pipes, return pipes, valves, valve springs, brakes, sensing components, etc. In addition, titanium can also be used for surface coating, and has been used to improve the surface performance of the brake plate, which can ensure that the quality of the brake plate is light and the service life is long. Titanium used in automobiles can prolong the service life of valves, springs and connecting rods.

titanium exhaust system for vehicles

  1. Other Sports Goods

Mountaineering and skiing equipment are developing towards lightweight and miniaturization. Titanium material has the characteristics of light weight, high strength and no reduction of impact value at low temperature. As a superior mountaineering and skiing tool material, it has been widely used, such as titanium alloy mountaineering stick, mountaineering sole nail, rock climbing fastener, ski stick, skate knife, etc. Titanium sports goods include fencing protective mask, sword, fishing rod, fishing winding frame, rowing parts, injection moulded Ti-Fe series sole nails for track and field running shoes, etc.

Titanium Alloy Forging–Hot Die Forging

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Like isothermal forging, hot die forging is a promising precision forging process. The difference is that the die temperature of hot die forging is higher than that of common forging, but lower than that of isothermal forging. Typical hot die forging die temperature is 110 – 225 C lower than blank temperature. Compared with isothermal forging, die materials can be widely used because of the decrease of die temperature, but the ability of forming very thin and complex shape forgings is slightly poor.

hot die forging of titanium

Compared with conventional forging, hot die forging has the following advantages:

(1) Reducing the material consumption of forgings during hot die forging reduces the quenching of the die contacting blank and the work hardening of the material, and improves the Forgability of the material. Therefore, the forgings are allowed to have smaller fillet radius, smaller die drawing inclination and smaller forging allowance, thus greatly reducing the quality of the forgings. For example, the quality of a Ti-6Al-4V alloy structural part is 28 kg. The quality of the forgings produced by conventional forging process is 154 kg. The quality of the forgings produced by hot die forging process is 109 kg. The difference between the two methods is 45 kg.

(2) Reduce the number of forging operations and improve the working ability of the press. When hot die forging, the die temperature is higher and the blank temperature drops less. Conventional forging requires two, three or more fires to form the forgings. Hot die forging only takes one time and can be completed at most two fires. Because of hot die forging, the metal deformation resistance is low, which increases the working capacity of the equipment relatively.

(3) Reduce the amount of forgings machined, because the forgings produced are close to the weight and contour size of the parts, so compared with the forgings produced by conventional forging, the amount of material removal in mechanical processing is reduced.

(4) The homogeneity of the product is better because the temperature gradient decreases greatly in the forging process and the uneven deformation caused by the temperature gradient is easy to alleviate. Therefore, the homogeneity and consistency of the structure and properties of the product are better than those of the forgings produced by conventional forging, but not as good as those produced by isothermal forging.

In hot die forging, although the blank has a temperature drop, it is still in the forging temperature range, and the deformation resistance does not rise as sharply as in conventional forging. The strain rate used in hot die forging varies from 0.05 to 0.2s-1. If the strain rate is too low, the billet temperature may decrease.

In hot die forging of titanium alloy, the heating temperature, strain rate, microstructure and holding time of preformed billet are very important factors, which play a decisive role in the dimensional accuracy and microstructures of formed parts. Generally, lower strain rate and longer holding time increase the possibility of precision forming. The microstructures of preform have direct effects on flow stress and superplasticity, especially on the structure after forging. It is not possible to eliminate the defects and grain inhomogeneity in raw materials completely by isothermal forging or hot die forging.

At present, whether titanium alloy and superalloy are forged by hot die mainly depends on the total cost of forgings or the need of uniformity and consistency of products. The development trend of this technology is to use conventional forging to preform billets and finally to finish isothermal or hot die forging.

Application Range and Properties of GR5 Titanium Alloy

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GR5 titanium alloy, also known as TC4 titanium alloy, we also call it 6Al4V, which is the most widely used titanium metal, usually we use titanium alloy refers to it. It has good forerunner and elongation.

Titanium and its alloys have many excellent properties, such as light weight, high strength, strong heat resistance, corrosion resistance and so on. They are known as “future metals” and are new structural materials with development prospects. Titanium and its alloys not only have very important applications in aviation and cosmic industries, but also have been widely used in many industrial sectors such as chemical industry, petroleum, light industry, metallurgy, power generation and so on. Titanium can resist the corrosion of human body and does no harm to human body. Therefore, it can be widely used in the medical and pharmaceutical industries. Titanium has good gas absorption performance and is widely used in electronic vacuum technology and high vacuum technology.

Grade 5 Titanium ingot manufacturer

Grade 5 titanium rod manufacturer

Ten Properties of GR5 Titanium Alloy

  1. Low density and high specific strength

Titanium metal has a density of 4.51g/cubic centimeter, higher than aluminium and lower than steel, copper and nickel, but its specific strength is the highest among metals.

  1. Corrosion resistance

Titanium is a very active metal. Its equilibrium potential is very low and its thermodynamic corrosion tendency in medium is high. But in fact, titanium is very stable in many media, such as oxidizing, neutral and weak reductive media. This is because titanium and oxygen have a great affinity. In air or medium containing oxygen, a dense, strong adhesion and inert oxide film is formed on the surface of titanium, which protects the titanium matrix from corrosion. Even due to mechanical wear, it can quickly self-heal or regenerate. This indicates that titanium is a metal with strong passivation tendency. Titanium oxide films at medium temperatures below 315 keep this characteristic all the time.

In order to improve the corrosion resistance of titanium, surface treatment technologies such as oxidation, electroplating, plasma spraying, ion nitriding, ion implantation and laser treatment have been developed, which have enhanced the protection of titanium oxide film and achieved the desired corrosion resistance. A series of corrosion-resistant titanium alloys, such as Ti-Mo, Ti-Pd, Ti-Mo-Ni, have been developed to meet the needs of metal materials in the production of sulphuric acid, hydrochloric acid, methylamine solution, high temperature wet chlorine and high temperature chloride. Titanium castings are made of Ti-32 molybdenum alloy. Ti-0.3 molybdenum-0.8 nickel alloy or Ti-0.2 palladium alloy are used locally in the environment where crevice corrosion or pitting corrosion often occurs. Good results are obtained.

  1. Good heat resistance

The new titanium alloy can be used for a long time at 600 C or higher.

  1. Good low temperature resistance

Low temperature titanium alloys, such as titanium alloy TA7 (Ti-5Al-2.5Sn), TC4 (Ti-6Al-4V) and Ti-2.5Zr-1.5Mo, have higher strength with lower temperature, but less plastic change. It is an ideal material for cryogenic containers, tanks and other equipment to maintain good ductility and toughness at low temperatures of – 196 – 253, avoiding cold brittleness of metals.

  1. Strong Damping Resistance

Compared with steel and copper, titanium has the longest vibration attenuation time when it is subjected to mechanical and electrical vibration. This property of titanium can be used as vibration element of tuning fork, medical ultrasonic pulverizer and vibration film of advanced loudspeaker.

  1. Non-magnetic and non-toxic

Titanium is a non-magnetic metal, which will not be magnetized in a large magnetic field. It is non-toxic and has good compatibility with human tissues and blood, so it is adopted by the medical profession.

  1. Tensile strength is close to yield strength.

This property of titanium shows that its yield strength ratio (tensile strength/yield strength) is high, which indicates that the plastic deformation of titanium metal is poor during forming. Because the ratio of yield limit to elastic modulus of titanium is large, the resilience of titanium during forming is great.

  1. Good heat transfer performance

Although the thermal conductivity of titanium is lower than that of carbon steel and copper, the wall thickness of titanium can be greatly reduced due to its excellent corrosion resistance, and the heat transfer mode between surface and steam is dropwise condensation, which reduces the heat group and the thermal resistance can also be reduced if the surface is too non-scaling, so that the heat transfer performance of titanium can be significantly improved.

  1. Low modulus of elasticity

The elastic modulus of titanium at room temperature is 106.4 Pa, which is 57% of that of steel.

  1. Inhalation performance

Titanium is a metal with very active chemical properties. It can react with many elements and compounds at high temperature. Titanium gas absorption mainly refers to the reaction with carbon, hydrogen, nitrogen and oxygen at high temperature.

Free Forging Technology for Titanium Alloy Forging

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Free forging is mainly used for the initial processing of ingots, i.e. the semi-finished bar with round, square or rectangular cross sections. When free forging is more economical than die forging in single or small batch production, it is usually used to manufacture large-size blanks.

Titanium Free forging technology from Baoji hosn titanium co., ltd.

From ingot to finished bar, the forging process is usually divided into three stages.

  1. Blanking

Its initial forging (billet) temperature is 150-250 C above the beta transition point, at which time, the plasticity of casting structure is the best. At the beginning, the ingot should be deformed by lightly and rapidly striking until the primary coarse grain structure is broken. The degree of deformation must be kept in the range of 20%-30%. The ingot is forged into the required cross section and then cut into a blank of fixed size.

The plasticity increases after the casting structure is broken. Aggregation recrystallization is aggravated with the increase of temperature, holding time and grain refinement. In order to prevent agglomeration recrystallization, forging temperature must be gradually reduced with grain refinement, and heating and holding time should be strictly controlled.

  1. Multidirectional repeated upsetting

It starts forging at 80-120 above the temperature of beta transition point, alternately upsetting and drawing 2-3 times, and alternately changing the axis and edge. In this way, a very uniform recrystallized fine grain structure with deformation characteristics in the beta region can be obtained in the whole section of the blank. If the blank is rolled on a rolling mill, such multi-direction upsetting is not necessary.

  1. Second multiple upsetting

It is the same as the first multi-directional upsetting, but the initial forging temperature depends on whether the semi-finished product is the blank of the next process or the product delivered. If the blank is used for the next process, the initial forging temperature can be 30-50 C higher than the beta transition temperature; if the product is delivered, the initial forging temperature is 20-40 C below the beta transition temperature.

Because of the low thermal conductivity of titanium, when upsetting or drawing blanks on free forging equipment, X-shaped shear bands are often formed on the vertical or cross sections if the preheating temperature of tools is too low, the strike speed of equipment is low and the deformation degree is large. This is especially true for non-isothermal upsetting on hydraulic press. This is because the tool temperature is low and the contact between the billet and the tool causes the surface cooling of the metal billet. In the process of deformation, the deformation heat generated by the metal can not conduct to the surrounding heat, and a large temperature gradient is formed from the surface to the center. As a result, the metal forms a strong flow strain band. The larger the deformation degree is, the more obvious the shear band is. Finally, cracks are formed under the action of tensile stress with opposite symbols. Therefore, when forging titanium alloy freely, the strike speed should be faster, the contact time between the blank and the tool should be shortened as far as possible, and the tool should be preheated to a higher temperature as possible. At the same time, the deformation degree in one stroke should be properly controlled.

When forging, the edges and corners are cooled fastest. Therefore, it is necessary to turn the blank several times during drawing and adjust the hammering force so as to avoid the sharp angle. In hammer forging, the initial stage should be lightly beaten, and the degree of deformation should not exceed 5%-8%. Then the amount of deformation can be gradually increased.