Treatment of surface defects after titanium forgings are made into parts

Since titanium forgings are made into parts, their stress, importance, and working conditions are different during use, and their materials and metallurgical processes are also different. Therefore, different parts are divided into titanium forgings according to the above conditions and in accordance with the requirements of this department. In terms of categories, different departments and different standards classify titanium forgings differently. But in any case, the quality inspection of titanium forgings as a whole is inseparable from two types of inspections, namely the inspection of appearance quality and internal quality, but the categories of titanium forgings are different, and the specific inspection items, inspection quantities and inspection requirements Just different. For example, some industrial departments classify structural steel, stainless steel, and heat-resistant steel F9 Titanium Forging into Class IV for inspection; some departments classify aluminum alloy titanium forgings and die titanium forgings Aluminum alloy and copper alloy titanium forgings are divided into category IV for inspection.

Specifically, the appearance quality inspection of titanium forgings is to check whether the shape and geometric dimensions of titanium forgings meet the requirements of the drawing, whether there are defects on the surface of titanium forgings, what kind of defects are, and what are their morphological characteristics. The inspection content of the surface state is generally to check whether there are surface cracks, folds, wrinkles, pressure pits, orange peel, blisters, scars, corrosion pits, bruises, foreign objects, underfilling, pits, lack of meat, etc. on the surface of titanium forgings. Defects such as scratches. The internal quality inspection is to check the internal quality of the titanium forging itself, which is a quality condition that cannot be found in the appearance quality inspection. It includes not only checking the internal defects of the titanium forging, but also checking the mechanical properties of the titanium forging, and for important and key parts. Or large titanium alloy forged rings should also be analyzed for chemical composition. For internal defects, we will use low-magnification inspection, fracture inspection, and high-magnification inspection to check whether titanium forgings have internal cracks, shrinkage cavities, porosity, coarse grains, white spots, dendrites, streamlines that do not conform to the shape, streamlines, etc. Defects such as disorder, flow-through, coarse-grain ring, oxide film, delamination, overheating, and overfired tissue. As for the mechanical properties, it is mainly to check the tensile strength at room temperature, plasticity, toughness, hardness, fatigue strength, high temperature instantaneous fracture strength, high temperature durable strength, durable plasticity and high temperature creep strength, etc.

The existence of defects in titanium forgings, some will affect the quality of subsequent processes or processing, and some will seriously affect the performance and use of titanium forgings, and even greatly reduce the service life of finished products, endangering safety. Therefore, in order to ensure or improve the quality of titanium forgings, in addition to strengthening quality control in the process and taking corresponding measures to prevent the occurrence of titanium forging defects, necessary quality inspections should also be carried out to prevent subsequent processes (such as heat treatment, surface treatment, Cold working) and titanium forgings with defects that have adverse effects on performance flow into subsequent processes. After the quality inspection, remedial measures can also be taken for the manufactured titanium forgings according to the nature of the defects and the extent to which they affect the use, so as to make them meet the technical standards or use requirements.

Therefore, in a sense, the quality inspection of titanium forgings, on the one hand, is to check the quality of titanium forgings that have been produced, and on the other hand, it is to point out the direction of improvement for the forging process, so as to ensure that the quality of titanium forgings meets the requirements of titanium forgings technical standards. And meet the requirements of design, processing and use. The quality inspection of titanium forgings includes the inspection of appearance quality and internal quality. Appearance quality inspection mainly refers to the inspection of geometric dimensions, shapes, surface conditions and other items of titanium forgings; internal quality inspection mainly refers to the inspection of chemical composition, macrostructure, microstructure and mechanical properties of titanium forgings.

How to deal with the surface of the titanium tube?

The alloying of the surface of the titanium tube can also be called a coating. Compared with the oxide coating of palladium coated on titanium, it has the advantages of strong bonding, wear resistance and corrosion resistance. Compared with titanium-palladium alloy, the surface content of palladium is high, which saves the precious metal palladium, reduces the cost, and also has excellent performance.

Aluminizing the surface of the Titanium Coil Tube can reduce the tendency of titanium to absorb hydrogen. Mixing 88% alumina, 4% aluminum fluoride and 8% aluminum powder and coating it on the titanium workpiece is the best aluminizing condition. The temperature is 810°C . The thickness and structure of the aluminized layer depend on the holding time. Using the cladding aluminizing method, a thin coating about 2 mm thick can be obtained by short-term diffusion, which has good bonding force and does not affect the mechanical properties of the substrate. The coating consists mainly of a titanium oxide phase, forming a very effective barrier against hydrogen permeation.

After the palladium plating on the Titanium Condenser Tubes, it can be heated by different methods to diffuse the palladium plating layer to the surface area of the titanium tube to form a titanium-palladium alloyed layer on the surface, thereby improving the corrosion resistance. Thermal diffusion or laser surface remelting are possible in principle. Use the laser to irradiate the titanium surface to make it melt and condense rapidly, so that the pre-vacuum-deposited 150-micron palladium film can be rapidly melted to form an effective palladium alloy.

Titanium tube has excellent high temperature and low temperature performance

titanium seamless tubings have excellent high and low temperature performance. Seamless titanium tubes can still maintain good mechanical properties at high temperatures, and their heat resistance is higher than that of aluminum alloys, and the operating temperature range is wider. At present, the operating temperature of new heat-resistant titanium alloys can reach 550-600 ° C; At low temperature, the strength of titanium alloy is increased than that at normal temperature, and it has good toughness. Low-temperature titanium alloy can maintain good toughness at -253°C.

When the titanium bicycle tubing is used, the lower opening of the outer tube is usually connected to the faucet, because the water will automatically flow upward when it is heated in the condenser tube, so as to achieve a greater cooling effect. Jinxi Titanium Industry Technology Co., Ltd. is committed to providing better quality titanium tubes. Titanium welded tubes serve as high-quality products for refrigeration equipment condensers.

Introduction of Titanium Tube Material Titanium Alloy

Titanium tubes are light in weight, high in strength and good in mechanical properties. Titanium tubes are widely used in heat exchange equipment, such as shell and tube heat exchangers, coil heat exchangers, serpentine tube heat exchangers, condensers, evaporators and pipelines. Many nuclear power industries use titanium tubes as standard tubes for their units. titanium seamless pipe

Titanium tube material Titanium alloy is an alloy composed of titanium and other elements. Titanium has two kinds of allotropic crystals: below 882°C is close-packed hexagonal structure α-titanium, and above 882°C is body-centered cubic β-titanium. Grade 3 Pure Titanium Tube

What should be paid attention to in titanium plate filter material

1. When using a grade 7 titanium alloy plate as a filter material, prevent it from being collided or scratched, and keep it well so as not to be polluted.

2. The use of titanium plate filter material cannot exceed its maximum working capacity.

3. Before entering the work, the titanium plate filter material must be activated first, and then it can be adjusted to the normal working environment.

4. Finally, the used Grade 3 Pure Titanium Plate material must be cleaned

Experience Introduction of Processing Methods for Titanium Alloy Materials

The pressure processing of titanium alloys has more similarities with steel processing than with the processing of non-ferrous metals and alloys. Many process parameters of grade 5 titanium round rod in forging, volume stamping and plate stamping are close to those of steel processing. But there are also some important features that must be paid attention to when press working titanium and titanium alloys.

Due to titanium's heat resistance, cooling is critical during titanium alloy machining. The purpose of cooling is to keep the cutting edge and tool surface from overheating. Use end coolant for excellent chip evacuation when shoulder milling as well as face milling pockets, pockets or full slots. When cutting Seamless Titanium Tube Grade 2, chips can easily stick to the cutting edge, causing the next round of milling cutter rotation to cut chips again, often causing edge line chipping. Each insert cavity has its own coolant hole/injection to solve this problem and enhance constant edge performance. Another clever solution is threaded cooling holes. Long edge milling cutters have many inserts. Applying coolant to each hole requires high pump capacity and pressure. But it is different, it can block the unnecessary holes according to the needs, so as to maximize the liquid flow to the required holes.

Medical basis of titanium alloy

The main advantages of using titanium and titanium alloys as human implants are (1) Density (20°C) = 4.5g/cm3, lightweight. Implanted into the human body: reduce the burden on the human body, as a medical device: reduce the operating load of surgical medical titanium wire personnel. (2) Low elastic modulus, pure titanium is 108500MPa, implanted in the human body: it is closer to the natural bone of the human body, which is beneficial to bone joint and reduces the stress shielding effect of bone on the implant. (3) Non-magnetic, not affected by electromagnetic fields and thunderstorms, which is beneficial to human safety after use. (4) Non-toxic, as an implant, it has no toxic side effects on the human body. (5) Corrosion resistance (biologically inert metal material), which has excellent corrosion resistance in the immersion environment of human blood, ensures good compatibility with human blood and cell tissue, does not produce human pollution as an implant, and does not Allergic reactions will occur, which is the basic condition for the application of titanium and titanium alloys. (6) High strength and good toughness. Due to trauma, tumors, and other factors that cause bone and joint damage, in order to establish stable bone support, arc-shaped plates, screws, artificial bones, and joints must be used. These implants should be left in place for a long time. In the human body, it will be subjected to bending, torsion, extrusion, muscle contraction, and other effects of the human body, requiring implants to have high strength and toughness.

Cleaning process of titanium alloy forging

The oxide scale and α-shell layer formed during the forging heat treatment of all titanium alloys are very brittle, and induce cracks in the subsequent forging or in the final forging or cause tool wear in the subsequent machining process. Therefore, it is recommended that titanium alloy processing remove scale and α-shells between continuous forgings, and scales and α-shells must be removed before forgings are delivered to users.

The cleaning technology of F9 Titanium Forgings has two aspects: one is the removal of oxide skin; the other is the removal of α shell. The scale can be removed mechanically, such as sandblasting; or chemically, such as molten salt derusting. The choice of rust removal method depends on the size, complexity and cost of the part.

Sandblasting is an effective method to remove rust scales. It can remove scales with a thickness of 0.13-0.76mm. It can use 100-150 mesh zircon sand or steel sand, and the air pressure can reach 275Pa. Although sand blasting is available for forgings of various sizes, it is mostly used for medium and large titanium alloy forgings. Sandblasting equipment can use abrasive drums, shot peening or sandblasting units. After sandblasting, it is pickled to remove the alpha shell.

Molten salt derusting is another effective method for removing scale, and pickling removes the alpha shell along with it. 1. The flow chart of rust removal and pickling by molten salt, solution composition and related parameters. The frame used for molten salt derusting is generally made of wood, titanium or stainless steel, in order to prevent electric potential from being generated between the workpiece and the frame, resulting in electrical erosion or arcing of the workpiece. Molten salt derusting is often used for medium and small forgings. In the case of large batches of forgings, the operating system can be fully automated.

What are the methods of cleaning titanium tubes?

Titanium tubes are light in weight, high in strength and superior in mechanical properties. Titanium tubes are widely used in heat exchange equipment, such as shell and tube heat exchangers, coil heat exchangers, serpentine tube heat exchangers, condensers, evaporators and pipelines. Many nuclear power industries use titanium tubes as standard tubes for their units. Huayu titanium tube manufacturer took us to see what are the methods of cleaning titanium heat exchanger tubing?

1. Alkaline cleaning: Soak the titanium tube with 3-5% sodium hydroxide analytically pure solution for 30-60 minutes at a temperature of about 40 degrees. Good in an ultrasonic cleaner. After immersion, flush the inside and outside with filtered deionized water or water for injection until neutral, and measure the conductivity. Blow dry with pure air ≥ 0.4Mpa pressure.

2. Pickling: Soak the Seamless Titanium Tube Grade 2 in 5% nitric acid solution for more than 8 hours at a temperature of 40 degrees. Good in an ultrasonic cleaner. After immersion, flush the inside and outside with filtered deionized water or water for injection until neutral, and measure the conductivity. Blow dry with pure air ≥ 0.4Mpa pressure.

3. The above two methods can be used alone or in conjunction with each other. If conditions permit, it can be combined with an ultrasonic cleaning machine for good results.

4. Organic matter pollution can be cleaned in combination with surfactants, and the debris pollution system combined with enzyme cleaning has a good effect.

Titanium alloy wear-resistant composite treatment technology

At present, driven by the growing industrial demand, composite coating technology will gradually replace single coating technology. Micro-arc oxidation is also called micro-plasma oxidation. This technology can prepare ceramic layers with good metallurgical properties on the surface of light metals Al, Mg, Ti and corresponding alloys with the help of high voltage, high current and instantaneous high temperature. The main component of the ceramic layer is the oxide grown in situ on the substrate, and the electrolyte components will also participate in the micro-arc oxidation film layer. The electrical parameters in the micro-arc oxidation process (such as solution formulation, voltage and current, duty cycle, pulse frequency, etc.) have a great influence on the preparation and microstructure of the micro-arc oxidation film. This method has the advantages of safe process, simple operation, and environment-friendly solution. It also has the advantages of simple process, uniform and dense film layer, and less restrictions on the size of workpieces, which cannot be compared with other treatment technologies.

ASTM F136 6Al-4V ELI Titanium Bar alloy micro-arc oxidation film has the advantages of high hardness, high bonding strength of film base, corrosion resistance and wear resistance, but the surface of the film layer is rough, loose and porous, and the friction coefficient is large, which reduces the wear resistance of the film layer. , which shortens the service life of the oxide film, which is not conducive to the application of titanium alloys in abrasive environments. At present, some research institutes of the Russian Academy of Sciences have carried out a lot of work to improve the defect of titanium alloy micro-arc oxidation film, but domestic attention to this issue has just started.

Medical basis of titanium alloy

The main advantages of using Titanium Grade 2 Round Bar and titanium alloys as human implants are: (1) Density (20°C) = 4.5g/cm3, light weight. Implanted into the human body: reduce the burden on the human body, as a medical device: reduce the operating load of medical personnel. (2) Low elastic modulus, pure medical titanium plate is 108500MPa, implanted in the human body: it is closer to the natural bone of the human body, which is beneficial to bone joint and reduces the stress shielding effect of bone on the implant. (3) Non-magnetic, not affected by electromagnetic fields and thunderstorms, which is beneficial to human safety after use. (4) Non-toxic, as an implant, it has no toxic and side effects on the human body. (5) Corrosion resistance (biologically inert metal material), which has excellent corrosion resistance in the immersion environment of human blood, ensures good compatibility with human blood and cell tissue, does not produce human pollution as an implant, and does not Allergic reactions will occur, which is the basic condition for the application of titanium and titanium alloys. (6) High strength and good toughness. Due to trauma, tumors and other factors that cause bone and joint damage, in order to establish a stable bone support, arc-shaped plates, screws, artificial bones and joints must be used. These implants should be left in place for a long time. In the human body, it will be subjected to bending, torsion, extrusion, muscle contraction and other effects of the human body, requiring implants to have high strength and toughness.

What are the common problems in the process of titanium alloy processing?

Titanium alloy has the characteristics of high strength, small specific gravity, corrosion resistance, low temperature resistance and high temperature resistance. According to the structure after annealing, it can be divided into α-phase titanium alloy, β-phase titanium alloy, and α-β-phase titanium alloy. The α-phase titanium rectangular bar alloy (TA type) cannot be strengthened by heat treatment, so the room temperature performance is not high, it has medium plasticity, and the machinability is acceptable. The β-phase Grade 3 Pure Titanium Sheet alloy can obtain higher room temperature performance through quenching and aging treatment. When α β phase titanium alloy (TC type) is processed, the contact length between the chip and the front is short, and the cutting force acts near the cutting edge. Due to the small thermal conductivity, the temperature of the cutting edge is high, which accelerates the wear of the drill bit, and due to work hardening The phenomenon is more serious, and the elastic coefficient is smaller, so the shrinkage of the drilled hole is larger, which also affects the life of the drill bit.

China Factory Best Price Chemical Industry Gr2 Gr1 Titanium Foil

Gr2 Pure Titanium Foil Basic Info

Surface

Acid Surface or Polishing

Color

Metallic

Tolerance

H7

Condition

R M Y

Service

OEM, ODM

Packaging

Wooden Cases Suitable for Overseas Shipment

Supply Ability

80tons Per Month

Payment Term

T/T, L/C and So on

Width

<500mm

Trademark

RG TECH

Transport Package

Plywood Box

Specification

Shape Foil Sheet Plate

Origin

China

Product Description

Grade 5 Ti-6Al-4V Titanium Foil Product Information

Item name	Titanium Plate, Titanium Sheet, and Titanium foil
Standard	ASTM B265
Grade	Gr1,Gr2,Gr3,Gr4,Gr5,Gr7,Gr9,Gr12,Gr23 etc.
Technology	Hot rolling, Cold rolling
Test	Ultrasonic test(UT),X-ray test
Thickness	Foil:  ≤ 0.3mm Plate: > 0.3mm
Standard specifications	Width: <1.1m Length: <2.2m Special specifications can be customized
Manufacturing methods	Hot rolling and cold rolling
Annealing temperature:	700~785°C
Size(mm)		Length	Width	Thickness
	Hot rolling	1000~4000	400~3000	4.1~60
	Cold rolling	1000~3000	400~1500	0.3~6

 


 

What are the precautions for grinding TC4 titanium alloy?

Since the titanium alloy material tends to fill the grinding wheel, it brings difficulties to the grinding of titanium alloy rods and Titanium Hot Rolled Sheet. During grinding, the high-temperature rise at the interface between the metal and the grinding wheel causes the grinding surface to have High residual stress, meanwhile, the surface finish is not ideal.

The following methods can be used to basically solve these difficulties:

(1) Choose a suitable grinding wheel, such as a silicon carbide grinding wheel, with medium grain size (60~80), medium hardness (J~M), a surface speed of 700~1200m/min, aluminum oxide (aluminum oxide powder or corundum) The grinding wheel should be used at a lower speed, such as 550~600min. Medium grain size is also required.

(2) Use a lower grinding wheel speed and feed rate; due to the low speed of the grinding wheel, fewer sparks are generated.

(3) Cooling with buffer or cutting fluid coolant, using ceramic bond and chlorinated or vulcanized cutting oil, can get good results. Whatever type of coolant is used, it needs to be well-filtered to eliminate "fishtail" stains due to the recirculation of titanium particles.

(4) Titanium sparks may catch fire when encountering oil mist, but immersing the workpiece in oil can reduce this danger. The anti-rust ammonium nitrite aqueous solution completely eliminates the risk of fire.

But even the best grinding conditions will reduce the fatigue performance of the workpiece

Common surface treatment methods for titanium alloy forgings

The density of titanium alloy is small, so the inertia of titanium liquid flow is small, and the fluidity of molten titanium is poor, resulting in low casting flow rate. The temperature difference between the casting temperature and the mold (300°C) is large, the cooling is fast, and the casting is carried out in a protective atmosphere. Defects such as pores on the surface and inside of titanium castings will inevitably appear, which has a great impact on the quality of titanium castings. The following describes titanium alloy forgings surface treatment method.

1. Removal of the surface reaction layer

The surface reaction layer is the main factor affecting the physical and chemical properties of titanium castings. Before grinding and polishing titanium castings, the surface contamination layer must be completely removed to achieve a satisfactory polishing effect. The surface reaction layer of titanium can be completely removed by pickling after sandblasting.

1. Sandblasting: For the sandblasting treatment of F9 Titanium Forging castings, it is generally better to use white corundum for rough spraying. The pressure of sandblasting is smaller than that of non-precious metals, and is generally controlled below 0.45Mpa. Because, when the injection pressure is too high, the sand particles impact the titanium surface to produce intense sparks, and the temperature rise can react with the titanium surface, forming secondary pollution and affecting the surface quality. The time is 15 to 30 seconds, and only the sand sticking, surface sintering layer and part of the casting surface and the oxide layer are removed. The remaining surface reaction layer structure should be quickly removed by chemical pickling. the

2. Pickling: Pickling can quickly and completely remove the surface reaction layer, and the surface will not be polluted by other elements. Both HF-HCl and HF-HNO3 pickling solutions can be used for pickling of titanium, but the HF-HCl series pickling solution has a large hydrogen absorption capacity, while the HF-HNO3 series pickling solution has a small hydrogen absorption capacity, which can control HNO3 The concentration of HF reduces hydrogen absorption, and can brighten the surface. Generally, the concentration of HF is about 3%~5%, and the concentration of HNO3 is about 15%~30%.

2. Treatment of casting defects

Internal pores and shrinkage cavity Internal defects: can be removed by hot isostatic pressing, but it will affect the accuracy of the denture. It is best to use X-ray flaw detection to remove the exposed pores on the surface and use laser repair welding. Surface porosity defects can be directly repaired by local laser welding.

3. Grinding and polishing

1. Mechanical grinding: titanium forging has high chemical reactivity, low thermal conductivity, high viscosity, low mechanical grinding ratio, and is easy to react with abrasive tools. Ordinary abrasives are not suitable for grinding and polishing of titanium. It is best to use good thermal conductivity. For superhard abrasives, such as diamond, cubic boron nitride, etc., the polishing line speed is generally 900~1800m/min. Otherwise, grinding burns and microcracks are prone to occur on the titanium surface.

2. Chemical polishing: Chemical polishing is to achieve the purpose of leveling and polishing through the oxidation-reduction reaction of metals in chemical media. Its advantage is that chemical polishing has nothing to do with the hardness of the metal, the polishing area has nothing to do with the structural shape, all the parts in contact with the polishing liquid are polished, no special complicated equipment is required, and the operation is simple. It is more suitable for polishing complex titanium denture brackets. However, the process parameters of chemical polishing are difficult to control, and it is required to have a good polishing effect on the denture without affecting the precision of the denture. the

4. Coloring

In order to increase the beauty of titanium dentures and prevent the discoloration of titanium dentures from continuous oxidation under natural conditions, surface nitriding treatment, atmospheric oxidation and anodic oxidation can be used for surface coloring treatment to make the surface light yellow or golden yellow and improve the titanium dentures. beauty. The anodic oxidation method utilizes the interference effect of the titanium oxide film on the light to produce natural color, and can form colorful colors on the titanium surface by changing the cell voltage.

Comparison of Three Processes for Hot Extrusion of Titanium Alloy Rods

Grade 2 Titanium Round Bar hot extrusion is to extrude the powder under the condition of increasing temperature so that the product can be fully densified. The hot extrusion method can accurately control the composition of the material and the internal structure of the alloy. The hot extrusion method can be divided into two types: the sheathed hot extrusion method and the non-sheathed hot extrusion method.

For active metal titanium and titanium alloy powder, in order to prevent product oxidation, the hot extrusion method is often used. At this time, the sheath is made first, and the powder or compact is packed in the sheath. After pre-drawing and sealing, it is placed in an extruder for hot extrusion.

The wrapping material used at this time should have good thermoplasticity, not form a solid metal with the material, be easy to peel off after hot extrusion, convenient source, and be low cost. Low-carbon steel or stainless steel sheets are mostly used.

6al4v titanium alloy bar hot extrusion is a process that combines forming, sintering, and thermal processing, so as to directly obtain diamond products with better mechanical properties.

The second process is to shape titanium and titanium alloy powder. After sintering, the prepared sintered billet is hot-extruded (for Ti-32Mo alloy, the temperature is 1000-1100° C.), and the properties of the obtained titanium alloy product are obtained. The effect of extrusion ratio on the properties of titanium materials.

The third process of titanium alloy rods is the process of filling billet extrusion, which is an important method that can be used to make complex cross-section products. The process includes: preparing the casing cavity, and determining the size of the cavity according to the required product size plus extrusion coefficient; Putting the powder into the cavity and vibrating; evacuating, exhausting, and sealing the sheath; extruding at a certain temperature and extrusion ratio; peel off the sheath.

Treatment of surface defects after titanium forgings are made into parts

Since titanium forgings are made into parts, their stress, importance, and working conditions are different during use, and the materials and metallurgical processes used are also different. Therefore, different parts are divided into titanium forgings according to the above conditions and the requirements of this department. Different categories, different departments, and different standards classify titanium forgings differently. But in any case, the overall quality inspection of titanium forgings is inseparable from two types of inspections, namely the inspection of appearance quality and internal quality, but the types of titanium forgings are different, and their specific inspection items, inspection quantities and inspection requirements. Just different. For example, some industrial departments divide structural steel, stainless steel, heat-resistant steel and F9 Titanium Forging into Class IV for inspection, some departments classify aluminum alloy titanium forgings and die titanium forgings into Class III for inspection according to their usage, and some departments will Aluminum alloy, copper alloy and titanium forgings are divided into IV categories for inspection.

Specifically, the appearance quality inspection of titanium forgings is to check whether the shape and geometric dimensions of titanium forgings meet the requirements of the drawing, whether the surface of titanium forgings is defective, what kind of defects are, and what are their morphological characteristics. The inspection content of the surface condition is generally to check whether the surface of titanium forgings has surface cracks, folds, wrinkles, pressure pits, orange peel, blistering, scars, corrosion pits, bumps, foreign objects, underfill, pits, lack of meat, etc. Defects such as scratches. The internal quality inspection is to check the internal quality of the titanium forgings itself, which is a quality condition that cannot be found by the appearance quality inspection. It includes not only checking the internal defects of the titanium forging, but also checking the mechanical properties of the titanium forgings. Or large titanium forgings should also undergo chemical composition analysis. For internal defects, we will check whether the titanium forgings have internal cracks, shrinkage holes, porosity, coarse grains, white spots, dendrites, streamlines that do not conform to the shape, and streamlines through low-power inspection, fracture inspection, and high-power inspection methods. Defects such as disorder, flow through, coarse grain ring, oxide film, delamination, overheating, and overburning structure. For the mechanical properties, it is mainly to check the normal temperature tensile strength, plasticity, toughness, hardness, fatigue strength, high temperature instantaneous rupture strength, high temperature durable strength, durable plasticity and high temperature creep strength.

The existence of defects in titanium forgings, some will affect the processing quality or processing quality of subsequent processes, and some will seriously affect the performance and use of titanium forgings, and even greatly reduce the service life of the finished products and endanger safety. Therefore, in order to ensure or improve the quality of titanium forgings, in addition to strengthening quality control in the process and taking corresponding measures to eliminate the occurrence of defects in titanium forgings, necessary quality inspections should also be carried out to prevent subsequent processes (such as heat treatment, surface treatment, Cold working) and titanium forgings with defects that have adverse effects on performance are passed into the subsequent process. After the quality inspection, remedial measures can also be taken for the manufactured titanium forgings according to the nature of the defects and the degree of influence on the use, so that they meet the technical standards or the requirements of use.

Therefore, in a sense, the quality inspection of titanium forgings, on the one hand, is to check the quality of the produced titanium forgings, and on the other hand, it is to point out the direction of improvement for the forging process, so as to ensure that the quality of titanium forgings meets the requirements of technical standards for titanium forgings. And meet the requirements of design, processing and use. The quality inspection of titanium forgings includes the inspection of appearance quality and internal quality. The appearance quality inspection mainly refers to the inspection of the geometric size, shape, surface condition and other items of the titanium forgings; the internal quality inspection mainly refers to the inspection of the chemical composition, macrostructure, microstructure and mechanical properties of the titanium forgings.

Why is the hardness required for titanium screws?

There is a lot of knowledge in titanium alloys. Titanium alloys refer to alloys composed of other elements based on titanium. Among them, titanium alloys include titanium aluminum alloys, titanium copper alloys, titanium manganese alloys and other 70 kinds of metals containing titanium elements. . titanium metric screw manufacturers say that the density of titanium alloys is generally around 4.51g/cm3, which is only 60% of that 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.

Parts with high unit strength, good rigidity and light weight can be produced. Titanium alloys are used in aircraft engine components, skeletons, skins, fasteners and landing gear. So when we customize titanium screws, how to choose the material of the screws, in fact, titanium alloys are produced to meet the different needs of the industry.

Since all the screws in the world are used in different environments, their positions on machine parts are also different, and the screw hardness, flexibility, heat conductivity and wear resistance required by the machine are also different. Therefore, when customizing the production of screw fasteners for customers, we will ask the user where the screws are used and what kind of performance do they need?

If hardness is required, it is recommended to use titanium-cobalt alloys, which are generally used to make cutting tools. When selecting the screw material, it must be understood that when the hardness of the screw is high, the titanium screw is easy to break.

Titanium screws are still the same as ordinary stainless steel screws. Titanium screws are actually no different from these everyday screws, but the material has changed. Titanium screws have an anti-corrosion effect and are fasteners used in a certain corrosive environment. Most of them are used in chemical, pharmaceutical, electronics, aviation and other fields.

Application of titanium standard parts and titanium bolts in daily life

Titanium standard parts are commonly used titanium screws, titanium bolts, titanium screws, etc., and are also widely used in daily necessities. titanium forging There are:

1. Used as shell materials: computers, cameras, game consoles, mobile phones, shavers, lighters, suitcases, etc.;

2. Used as lightweight materials: crutches, fishing rods, watches, hair clippers, antennas, musical instruments, kitchen utensils, spectacle frames, etc.;

3. Crafts and decorative materials: earrings, bracelets, rings, necklaces, brooches, etc.

Causes and Solutions of Cracks in Titanium Plates and Titanium-steel Composite Plates

Cracks are a frequent defect in the welding of titanium plates. Titanium weld cracks are cold cracks, mainly caused by hydrogen in the weld. The main sources of hydrogen are moisture and oil in the plate and welding wire, and the ambient humidity is the main reason for the increase of hydrogen in the weld.

Under the action of high temperature during welding, a large amount of hydrogen is dissolved in the molten pool. During the cooling and solidification process of the weld, hydrogen is easily escaped due to the rapid decrease in solubility. If the weld cooling rate is too fast, the hydrogen will not escape and remain in the weld, which will make the hydrogen in the weld supersaturated, so the hydrogen has to diffuse as much as possible, and promote further embrittlement of this area.

If there is a notch effect in this area and the hydrogen concentration is high enough, cracks may occur. Especially in winter construction, the ambient temperature is low, and the water vapor adheres to the AMS 4900 CP Titanium Sheet, which creates conditions for the hydrogenation of the weld. Because the titanium plate is too thin (1.2mm), the steel plate is relatively "warm", the temperature rises slowly, and the corresponding titanium composite layer weld is cooled too fast. During the cooling process, the residual hydrogen in the weld has no time to escape. It exists in the form of supersaturation in the weld, which eventually leads to the appearance of cracks.

Therefore, in the welding process of Grade 23 Ti-6Al-4V ELI Titanium Sheet, the surface of the base metal and welding wire should be carefully cleaned, and the ambient temperature should not be lower than 5 °C. During construction in winter, flame preheats the base steel surface, one is to remove the moisture around the weld; the other is to increase the temperature of the weldment and reduce the cooling rate of the weld.