2020年7月12日星期日

What are the precautions for alkaline cleaning of titanium alloy rods?

Alkaline washing of titanium alloy rods is easy to catch fire, especially alkali washing of titanium sheets is more likely to catch fire. The chemical activity of the titanium alloy rod in the lye, when alkaline washing in the lye containing an oxidant, the overall lye temperature is too high or the local temperature is too high are the reasons for the burning of titanium. Studies have shown that due to the potential difference between the titanium and steel tools in the lye, there is a galvanic effect. When titanium and steel are in contact, galvanic current is formed, and the smaller the contact point, the greater the current and the excessive contact. The current density causes local overheating so that the titanium alloy rod often starts to burn from the contact point of these two metals.
In order to prevent and reduce the ignition of titanium alloy rods during alkaline washing, the following measures can be taken:
1. Selection of qualified alkaline washing liquid components;
2. Strictly control the temperature of lye;
3. Insulate the alkali washing frame with high-temperature resistant coating or high temperature resistant insulating gasket. For example, if a stainless steel alkaline cleaning frame is used, ceramic strips or ceramic pieces can be placed to separate the titanium material from the steel frame, which can also avoid fire.
In the alkaline washing process of titanium alloy rods, the lye is continuously taken away or evaporated by the workpiece, so it is necessary to supplement the lye and adjust it in a timely manner to keep the composition of the lye relatively stable. During alkaline washing, insoluble oxide scale slag settles on the bottom of the tank, which affects the good thermal conductivity of the tank, and the gap caused by the precipitation makes the steel tank prone to electrochemical corrosion, which greatly shortens its service life. Therefore, the sediment should be cleaned up in time. The use of a movable tank bottom to collect slag is a common method. When it is necessary to eliminate sediments, just hang the bottom of the movable tank.

2020年7月9日星期四

Performance analysis and main application areas of titanium forgings and titanium castings

After forging, the metal can improve its structure and mechanical properties. After hot working deformation of the casting structure, the original coarse dendrites and columnar grains are transformed into fine-grained and uniform-sized equiaxed recrystallized structures due to the deformation and recrystallization of the metal, which causes the original segregation, The compaction and welding of loosening, porosity, slag inclusion, etc., the organization becomes tighter, improving the plasticity and mechanical properties of the metal.
Generally speaking, the mechanical properties of castings are lower than those of forgings of the same material. In addition, the forging process can ensure the continuity of the metal fibre structure, keep the fibre structure of the forging consistent with the shape of the forging, and the metal flow line is complete, which can ensure that the parts have good mechanical properties and long service life. Precision dies forging and cold extrusion, Forgings produced by warm extrusion and other processes are unmatched by castings.
1. Aircraft forgings
By weight, about 85% of the components on the plane are forgings. Aircraft engine turbine disks, rear axle journals (hollow shafts), blades, wing spars, fuselage rib plates, wheel brackets, inner and outer cylinders of landing gear, etc. are all important forgings related to aircraft safety. Aircraft forgings are mostly made of precious materials such as high-strength wear-resistant and corrosion-resistant aluminium alloys, titanium alloys, and nickel-based alloys. In order to save materials and energy, aircraft forgings are mostly produced by die forging or multi-directional die forging presses. Car forging is calculated by weight, there are 1719% of forgings on the car. The general automobile is composed of 15 parts such as body, trunk, engine, front axle, rear axle, frame, gearbox, transmission shaft, steering system, etc. The characteristics of automobile forgings are complex appearance, lightweight, poor working conditions, and safety High standard. Such as crankshafts, connecting rods, camshafts used in automobile engines, front beams required for the front axle, steering knuckles, half shafts used in the rear axle, half axle bushings, transmission gears in the axle box, etc. Key forgings for the safe operation of automobiles.
2. Diesel engine forgings
The diesel engine is a kind of power machinery, it is commonly used as an engine. Take a large diesel engine as an example, the forgings used are cylinder head, main journal, crankshaft flange output shaft, connecting rod, piston rod, piston head, crosshead pin, crankshaft transmission gear, ring gear, intermediate gear and dye pump More than ten kinds of body.
3. Marine forgings
Marine forgings are divided into three categories: mainframe forgings, shafting forgings and rudder forgings. The main engine forging is the same as the diesel engine forging. Shaft forgings include thrust shaft, intermediate shaft and stern shaft. Rudder forgings include rudder stock, rudder post, rudder pin, etc.
4. Weapon forgings
Forgings occupy an extremely important position in the weapon industry. By weight, 60% of the tanks are forgings. Barrels, muzzle brakes and breech in artillery, rifled barrels and triangular bayonets in infantry weapons, rocket and submarine deep-water bomb launchers and mounts, stainless steel valve bodies for high-pressure coolers in nuclear submarines, shells, Bullets, etc. are all forged products. In addition to steel forgings, weapons are also made of other materials.
5. Petrochemical forgings
Forgings are widely used in petrochemical equipment. Such as manholes and flanges of spherical storage tanks, various tube sheets required for heat exchangers, full-forged cylinders (pressure vessels) of butt-welded flange catalytic cracking reactors, cylinder sections used in hydrogenation reactors, and fertilizers The top cover, bottom cover, head, etc. required by the equipment are all forgings.
grade 9 titanium wire     grade 5 titanium tube     titanium flat rod     titanium foil sheet

2020年7月7日星期二

Application function of titanium plate and titanium alloy plate in the petrochemical industry

Titanium alloy plates and titanium plates are mainly used to manufacture various vessels, reactors, heat exchangers, distillation towers, pipes, pumps and valves in the petrochemical machinery manufacturing industry. Titanium can be used as a condenser for titanium cathodes and power stations and as an environmental pollution control device. The hardness of steel is higher than that of titanium plate, but the specific strength or tensile strength of titanium alloy is higher than that of high-quality steel. Titanium alloys have good heat resistance, low-temperature toughness and fracture toughness, so they are mostly used as aircraft engine parts and rocket and missile structural parts. Titanium alloys can also be used as fuel and oxidant storage tanks and high-pressure containers. Titanium alloys are now used to manufacture automatic rifles, mortar seat plates, and launch tubes for recoilless guns.
1. Memory function
Titanium-nickel alloys have unidirectional, bidirectional and omnidirectional memory effects at certain ambient temperatures and are recognized as the preferred memory titanium alloys. It is used in engineering to make pipe joints for the oil pressure system of fighter jets; oil pipeline system of petroleum joint enterprises; 500mm diameter parabolic mesh antenna made of 0.5mm diameter wire is used in aerospace vehicles; it is used to make snoring in medical engineering Treatment; screws made of titanium plates are used for fracture healing. The above applications have achieved obvious results.
2. Superconducting function
The niobium-titanium plate exhibits a superconducting function with zero resistance when the temperature is lower than the critical temperature.
3. Hydrogen storage function
Titanium-iron alloys have the property of absorbing hydrogen. They store large amounts of hydrogen safely and release it in a certain environment. This is very promising in applications such as hydrogen separation, hydrogen purification, hydrogen storage and transportation, manufacturing of heat pumps and batteries that use hydrogen as an energy source.
The titanium oxide, titanium dioxide, is a snow-white powder and a good white pigment, commonly known as titanium white. In the past, people mine titanium ore, the main purpose is to obtain titanium dioxide. Titanium white has strong adhesion, is not easy to change chemically, and is always white. Especially valuable is that titanium dioxide is non-toxic. It has a high melting point and is used to make refractory glass, glaze, enamel, clay, high-temperature resistant laboratory utensils, etc.

2020年7月5日星期日

Titanium alloy-the difference between butt welded titanium flange with neck and flat welded titanium flange with neck

There are three main points:
1. The welding seam forms are different: the welding seam form of the titanium flange pipe with neck flat welding and the titanium flange is a fillet weld, and the welding seam form of the neck welding neck flange and the pipe is a circular weld;
2. The materials are different: the material of the neck welded flange is made of ordinary titanium plate with a thickness that meets the requirements, and the material of the neck welded flange is mostly machined from titanium forgings;
3. Different nominal pressures: the nominal pressure of the neck-welded flange is: 0.6---4.0MPa, while the nominal pressure of the neck-welded flange is: 1--25MPa;
4. One more point, the welding seam with the neck butt welding flange and the connecting pipe belongs to category B seam, and the welding seam with the neck flat welding flange and the connecting pipe belongs to category C seam, and the non-destructive testing after welding is different;
5. The flat welded flange with neck and the butt welded flange with neck can not be replaced casually. In terms of manufacturing angle, the large internal welded flange with neck (SO is the abbreviation of SLIP ON) means that the weight is small and the cost is low. In addition Welding flanges with necks with a nominal diameter greater than 250mm (WN is the abbreviation of WELDING NECK) to be tested, SO flanges do not need to be tested, so the cost is low.
ASTM B265 TA6V Titanium Plate     Ti 6Al-2Sn-4Zr-6Mo Titanium Rod      AMS 4900 CP Titanium Sheet 

2020年7月3日星期五

Analysis of the forging process of titanium alloy GR5 material

Because of its high strength, corrosion resistance, high specific strength, wear resistance, high-temperature resistance, low-temperature resistance, non-magnetic properties, biophilic, and rich resources, titanium and titanium alloys have been favoured by all walks of life this year.
And gradually in oil drill pipe, oil exploration, oil drilling platform, vacuum coating, mining equipment, coal chemical equipment, pressure equipment accessories, high-temperature equipment accessories, deep-sea detection equipment accessories, wear-resistant equipment accessories, corrosion-resistant equipment accessories, gas Drilling equipment, sports equipment, automobiles, motorcycles, computers, mobile phones and other high-pressure resistant, wear-resistant, corrosion-resistant fields have been widely used and popularized.
The cleaning technology of titanium alloy forgings has two aspects: one is the removal of oxide scale; the second is the removal of α shell. Rust can be removed by mechanical methods, such as sandblasting; or chemical methods, 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. It can remove rust from 0.13 to 0.76mm thick. 100 to 150 mesh zircon sand or steel sand can be used. The air pressure can reach 275Pa. Although sandblasting can be used for forgings of various sizes, it is mostly used for medium and large titanium alloy forgings. Sandblasting equipment can use drums, shot blasting or sandblasting devices equipped with abrasives. After sandblasting, pickling is required to remove the alpha shell.
Dissolved salt rust removal is another effective method for removing scale, and the alpha shell is also removed by acid pickling. First, the flow chart of solution salt removal and pickling, solution composition and related parameters are usually used. The racks used for dissolving salt to remove rust are generally made of wood, titanium or stainless steel to prevent the generation of electric potential between the workpiece and the rack, which may cause electrical erosion or arcing of the workpiece. Molten salt descaling is often used in small and medium-sized forgings. In the case of large-scale forgings, the operating system can be fully automated.

2020年6月30日星期二

To introduce you to the performance of titanium alloy pipe products:

Product performance:
1. Excellent corrosion resistance in many media
2. Small density, high strength, equipment weight
3. The surface is smooth and free of dirt, the dirt coefficient is greatly reduced

Executive standards and materials: HG/T3651-99 GB/T12459, GB/T13401, etc.
Titanium pipe use: widely used in petroleum, chemical industry, electric power, metallurgy, chemical fibre, food, pharmaceutical, Chlor-alkali, vacuum salt production, fine chemical industry, biological engineering, seawater desalination, marine engineering and other industries.
Product packaging: wooden box packaging, suitable for long-distance transportation.

2020年6月28日星期日

Metal corrosion of heat exchanger:

The principle of metal corrosion: Metal corrosion refers to the destruction of metal under the action of chemical or electrochemical surrounding media, and often under the joint action of physical, mechanical or biological factors, that is, the metal in its environment The damage caused by the effect.
Several common types of corrosion damage of heat exchangers:
1. Uniform corrosion, which occurs on the entire surface exposed to the medium or on a larger area. Macroscopically uniform corrosion damage is called uniform corrosion.
2. Contact corrosion. Two metals or alloys with different potentials are in contact with each other and immersed in the electrolyte solution. When there is current between them, the corrosion rate of metals with positive potential decreases and the corrosion rate of metals with negative potential increases.
 3. Selective corrosion. The phenomenon that a certain element in the alloy preferentially enters the medium due to corrosion is called selective corrosion.
4. The pitting corrosion is concentrated on the individual small spots on the metal surface. The deeper corrosion is called pitting corrosion, or small hole corrosion, pitting corrosion.
5. Crevice corrosion, there will be severe crevice corrosion in the crevices and covered parts of the metal surface.
6. Scour corrosion, scour corrosion is a kind of corrosion that accelerates the corrosion process due to the relative movement between the medium and the metal surface.
7. Intergranular corrosion. Intergranular corrosion is a kind of corrosion that preferentially corrodes the grain boundaries of metals or alloys and the areas near the grain boundaries.
8. Stress corrosion cracking (SCC) and corrosion fatigue SCC is a material fracture caused by the combined action of corrosion and tensile stress in a certain metal-medium system.
9. Hydrogen destruction. Metals in electrolyte solutions can be damaged due to hydrogen penetration due to corrosion, pickling, cathodic protection or electroplating.

The production of titanium rods requires a heat treatment process

The production of titanium rods usually requires a heat treatment process to improve the material properties of the titanium alloy, remove i...