The weight of titanium material calculated according to the above formula is called theoretical weight. In the actual processing, there will be some tolerances in size and precision accuracy, which will affect the actual weight of the product. The theoretical weight can be known as a reference, the actual weight is a more important and practical factor that can be ignored, especially in the process of shipping and installation, the difference between these two weights will greatly affect the cost and design and installation.
Titanium tubes are made by two different processes. The overall production method for both processes involves three steps. First, raw steel is converted into a more workable form. Next, the pipe is formed on a continuous or semicontinuous production line. Finally, the pipe is cut and modified to meet the customer’s needs.
Seamless pipe is manufactured using a process that heats and molds a solid billet into a cylindrical shape and then rolls it until it is stretched and hollowed. Since the hollowed center is irregularly shaped, a bullet-shaped piercer point is pushed through the middle of the billet as it is being rolled.
1 Molten steel is made by melting iron ore and coke (a carbon-rich substance that results when coal is heated in the absence of air) in a furnace, then removing most of the carbon by blasting oxygen into the liquid. The molten steel is then poured into large, thick-walled iron molds, where it cools into ingots.
2 In order to form flat products such as plates and sheets, or long products such as bars and rods, ingots are shaped between large rollers under enormous pressure.
PRODUCING BLOOMS AND SLABS
3 To produce a bloom, the ingot is passed through a pair of grooved steel rollers that are stacked. These types of rollers are called “two-high mills.” In some cases, three rollers are used. The rollers are mounted so that their grooves coincide, and they move in opposite directions. This action causes the steel to be squeezed and stretched into thinner, longer pieces. When the rollers are reversed by the human operator, the steel is pulled back through making it thinner and longer. This process is repeated until the steel achieves the desired shape. During this process, machines called manipulators flip the steel so that each side is processed evenly.
4 Ingots may also be rolled into slabs in a process that is similar to the bloom making process. The steel is passed through a pair of stacked rollers which stretch it. However, there are also rollers mounted on the side to control the width of the slabs. When the steel acquires the desired shape, the uneven ends are cut off and the slabs or blooms are cut into shorter pieces.
5 Blooms are typically processed further before they are made into pipes. Blooms are converted into billets by putting them through more rolling devices which make them longer and more narrow. The billets are cut by devices known as flying shears. These are a pair of synchronized shears that race along with the moving billet and cut it. This allows efficient cuts without stopping the manufacturing process. These billets are stacked and will eventually become seamless pipe.
6 Slabs are also reworked. To make them malleable, they are first heated to 2,200° F (1,204° C). This causes an oxide coating to form on the surface of the slab. This coating is broken off with a scale breaker and high pressure water spray. The slabs are then sent through a series of rollers on a hot mill and made into thin narrow strips of steel called skelp. This mill can be as long as a half mile. As the slabs pass through the rollers, they become thinner and longer. In the course of about three minutes a single slab can be converted from a 6 in (15.2 cm) thick piece of steel to a thin steel ribbon that can be a quarter mile long.
7 After stretching, the steel is pickled. This process involves running it through a series of tanks that contain sulfuric acid to clean the metal. To finish, it is rinsed with cold and hot water, dried and then rolled up on large spools and packaged for transport to a pipe making facility.
8 Both skelp and billets are used to make pipes. Skelp is made into titanium welded pipe. It is first placed on an unwinding machine. As the spool of steel is unwound, it is heated. The steel is then passed through a series of grooved rollers. As it passes by, the rollers cause the edges of the skelp to curl together. This forms an untitanium welded pipe.
9 The steel next passes by welding electrodes. These devices seal the two ends of the pipe together. The welded seam is then passed through a high pressure roller which helps create a tight weld. The pipe is then cut to a desired length and stacked for further processing. Welded titanium tube is a continuous process and depending on the size of the pipe, it can be made as fast as 1,100 ft (335.3 m) per minute.
10 When seamless pipe is needed, square billets are used for production. They are heated and molded to form a cylinder shape, also called a round. The round is then put in a furnace where it is heated white-hot. The heated round is then rolled with great pressure. This high pressure rolling causes the billet to stretch out and a hole to form in the center. Since this hole is irregularly shaped, a bullet shaped piercer point is pushed through the middle of the billet as it is being rolled. After the piercing stage, the pipe may still be of irregular thickness and shape. To correct this it is passed through another series of rolling mills.
11 After either type of pipe is made, they may be put through a straightening machine. They may also be fitted with joints so two or more pieces of pipe can be connected. The most common type of joint for pipes with smaller diameters is threading—tight grooves that are cut into the end of the pipe. The pipes are also sent through a measuring machine. This information along with other quality control data is automatically stenciled on the pipe. The pipe is then sprayed with a light coating of protective oil. Most pipe is typically treated to prevent it from rusting. This is done by galvanizing it or giving it a coating of zinc. Depending on the use of the pipe, other paints or coatings may be used.
A variety of measures are taken to ensure that the finished titanium tube meets specifications. For example, x-ray gauges are used to regulate the thickness of the steel. The gauges work by utilizing two x rays. One ray is directed at a steel of known thickness. The other is directed at the passing steel on the production line. If there is any variance between the two rays, the gauge will automatically trigger a resizing of the rollers to compensate.
Pipes are also inspected for defects at the end of the process. One method of testing a pipe is by using a special machine. This machine fills the pipe with water and then increases the pressure to see if it holds. Defective pipes are returned for scrap.
Quality testing for seamless pipe
Seamless titanium tube quality testing is a very important step, and for its detection method is also very particular to now all three – ultrasonic testing, eddy current testing, magnetic flux leakage testing, specific circumstances are as follows:
THE ULTRASONIC TESTING
Ultrasonic inspection of seamless pipes
For steel quality inspection, ultrasonic testing, including for the purpose of detected defects ultrasonic testing and ultrasound to measure the dimensions for the purpose of measuring. Wider application of the former, automated testing, manually testing; latter application, generally manual measurement.
Nondestructive Testing, shorted for NDT, is a widely-used method in pipeline inspection. It is a process of testing, inspecting and evaluating the quality and characteristics of the material without damaging the pipeline itself or affecting the later regular work of the pipe. In other words, after NDT testing, the part can still be put into practical use. NDT utilizes the changes in heat, sound and magnets caused by abnormal inner structure or flaws to inspect the internal and external defects of the material.
The common inspection methods of NDT are visual testing (VT), ultrasonic testing (UT), radiographic testing (RT), hydrostatic testing. Anson International co, ltd uses ultrasonic testing (UT) and hydrostatic testing to inspect its line pipes.
In order to verify the mechanical properties of seamless titanium tube to meet the requirements of the standard, the test sample of seamless titanium tube mechanical performance should be prepared carefully. Mechanical property test includes tensile strength, yield strength, elongation, impact energy and so on. Process performance test includes flattening test, flaring test, hydrostatic testing, curling trials, cold bend test, perforation test. These test items are based on different standards and different uses of seamless steel tubes.
THE MAGNETIC FLUX LEAKAGE TESTING
The magnetic flux leakage testing is a non-destructive testing technology based on ferromagnetic material magnetic changes. When the ferromagnetic material is magnetized, and generates a leakage magnetic field due to the presence of defects on the workpiece surface, and therefore, through the detection of the magnetic flux leakage can be found in defects in the large caliber Seamless thermal expansion material. Titanium tube magnetic flux leakage testing technology is divided into two kinds of magnetic particle inspection method and magnetic field measurement method. The former is simple, but requires the naked eye to observe the magnetic marks, it is difficult to automate. The latter despite the device complexity, high cost and the operation is difficult, but it is picked up by sensors leakage magnetic field information, and therefore easy to automate testing suitable for the automatic inspection of large quantities of titanium tube. Therefore, under normal circumstances, no special instructions, usually refers to the magnetic field of the magnetic flux leakage testing of titanium tubes assay.
EDDY CURRENT TESTING
ECT-620 Eddy Currentautomatic Test System
Eddy current testing method is more wide range of applications in the industrial field of non-destructive testing methods. It is based on the theory of electromagnetic induction, without any coupling agent can 100% fast automatic detection of the specimen. it is even more powerful tool for the rapid detection of bulk. Therefore, it is even not limited to the large caliber thermal expansion seamless titanium tube, has become a necessary means of various types of steel quality inspection. Automatic eddy current testing method is mainly suitable for quality inspection of titanium tubes a little probe testing method and through-probe testing method two.
The former method of using the high-speed rotation of the point probe to detect longitudinal defects in the titanium tube, the detection speed is determined by the quantity of the probe and the speed of rotation, in general, is relatively slow, and the latter through the probe to detect the titanium tube transverse defects, this method is simple, and the testing speed (generally up to 60m/min), Further, since the eddy current flaw detection method is particularly sensitive pair of through holes, the related standards of the main method is to replace the pipe hydrostatic test.
Titanium seamless pipe and titanium welded pipe are mainly different molding process. Welded steel pipe, such as water pipes, generally through the flat plate by welding after bending up, you can find a seam in the above; is generally thicker in diameter spiral weld. The titanium seamless pipe is generally the molten steel through the annular slit of the backlog by stretching out before treatment processes such as molding, so that no seam. In performance, especially on the bearing capacity has greatly improved as compared with ordinary steel, it is often used for high voltage devices. Such as hydraulic equipment, piping connections. The titanium welded pipe weld area is its weak link, weld quality is also affecting the overall performance of the main factors
Seamless pipe: titanium seamless pipe is a kind of hollow cross-section, no seams around the circle, square, rectangular steel. Titanium seamless pipe or solid steel ingot is made of the capillary tube through the hole, then through the hot-rolled, cold rolled or cold call is made. Titanium seamless pipe with a hollow cross-section, a large number of pipes for conveying fluids, such as steel and solid steel round bar compared to the same torsional strength in bending, lighter, is an economic cross-section steel, widely used in the manufacture structural parts and mechanical parts, such as drill pipe, automotive drive shafts, bicycle frames and construction using steel scaffolding.
Welded pipe: titanium welded pipe, also known as pipe, plate or strip is formed through the curl made of steel after welding. Welded steel pipe production process is simple, efficient, and more varieties and specifications, equipment, less capital, but the general strength of less than titanium seamless pipe.
Concentricity: The process of manufacturing titanium seamless pipe is a hole punched out in a stainless steel billet temperature of 2200 ° f the, in this high temperature, the tool steel by stamping and drawing softens and spirally from Kongzhong Cheng-shaped out. So that the wall thickness of the pipe is not uniform and high eccentricity. Thus astm allows titanium seamless pipe wall thickness than a slit pipe wall thickness difference. Precision cold-rolled plate (width of 4-5 feet per roll) made a slit pipe. These cold rolled sheet is usually the largest wall thickness difference is 0.002 inches. The steel sheet was cut into a width πd, where d is the outer diameter of the pipe. Titanium Welded Pipe wall thickness tolerance is very small, and the entire circumference of the wall thickness is very uniform. Molding process differences: Titanium seamless pipe can be formed one time in the rolling process. Welded steel pipe is manufacturing with steel strip or steel plate, through bending and different welding processes. Appearance difference: Titanium seamless pipe used steel billet as raw material. The outer surface defects of billet cannot be eliminated by hot rolling process, it is only polished after the product finished. In the process of wall reduction, the defect can only get partially eliminated. Welded steel pipe made by hot rolled coil as raw material, the surface quality of coil is just the pipe’s surface quality, and easy to control.The surface of hot rolled coil have high quality. So Welded steel pipe surface quality is much better than titanium seamless pipe. Performance and Usage: Titanium seamless pipe has better pressure capacity, strength is higher than ERW titanium welded pipe. So it is widely applied in high pressure equipment, and thermal, boiler industries. Generally the welding seam of the titanium welded pipe is the weak point, the quality affect overall performance. In general, titanium welded pipes can withhold 20% less working pressure than seamless ones. This reliability is the prime factor why people go for titanium seamless pipe. As a matter of fact, all the industrial pipelines are done with seamless pipes only because the pipes undergo extreme thermal, chemical and mechanical workloads. Welded pipes are more preferred in aerospace, automobile and electronics industries where the budget is comparatively low, and so is the work pressure put on the pipes. Welding performance: Average Titanium Welded Pipe and titanium seamless pipe the chemical composition has a certain difference. The production of seamless steel component is only astm the basic requirements. Produce titanium seamless pipe steel with the chemical composition suitable for welding. For example, silicon, sulfur, manganese, oxygen and triangle ferrite and other elements can be mixed according to a certain proportion in the welding process with an easy transfer heat weld, so that the entire weld penetration. The lack of the above chemical composition of the steel, seamless, for example, in the welding process will produce a variety of factors of instability, is not easy to weld and welding impervious. Grain size: usually, the grain size of the metal and the heat treatment temperature and to maintain the same temperature for the time. Therefore, annealed seam and titanium seamless pipes are the same grain size. If the slit pipe with minimum cold treatment, grain size smaller than the grain size of the weld metal of the weld, and otherwise, the grain size is the same. For most of titanium seamless pipe manufacturers in China, they produce original seamless pipe sizes maximum OD in 20 inch, 508 mm. Where usually is smaller than 16 inch, 406.4 mm, because of the equipment limits. And if client would like to purchase the titanium seamless pipe more than above sizes, then hot expanding machining shall be used. But usually this kind hot expanded titanium seamless pipe quality could not compare with the original titanium seamless pipe. On the contrary, titanium welded pipe don’t have these limitations, sizes available from 1-1/2 inch 48.3mm to 100 inch 2540 mm. Strength: the strength of the pipe depends on the alloy composition, which contains the same alloy and the same heat treatment of seamless and seamed pipe strength are the same in essence. After tensile test and three-dimensional vibration test, tear Titanium Welded Pipe occurs almost exclusively in a place away from the welding point or heated areas. This is because the weld impurities less and the nitrogen content is higher, and thus the strength of the weld is better in other parts. ASME Boiler and Pressure Vessel Association, however, that a slit pipe can only afford 85% of the license pressure, which is mainly due to the collection of data as early as welding equipment in use today have improved. ASME requirements 100% by ultrasonic test pipe joints can be fully exposed to the license pressure. Similarly, Europe and Asia also provides through the eddy current test pipe joints to guarantee the performance of the welding quality, eddy current testing require the approval of the legal procedures and permit institutions. The trent eddy current testing by the permission of the Swedish Ministry of Energy. The ASME think current loss is smaller quality performance is based on a slit pipe. Corrosion resistance: corrosion resistance, good or bad is also vary depending on the composition of the alloy. The same chemical composition fully heat-treated seamless and the Titanium Welded Pipe corrosion resistance. ASTM provide supplementary test can prove the corrosion resistance of the weld is equal to or better than the metal being welded. Incomplete Titanium Welded Pipe welding heat treatment in acidic chloride environment, corrosion will be accelerated, but only need corrosion test is, in fact, their environment is not so bad. Bending and extension: extension of the welding at the following tests can be specified by ASTM Verification: bend 45 °, then bent to 90 °, then flattened along the weld Titanium Welded Pipe Repeat the above steps; then turned so that the weld bending diameter up to 180 °. Weld quality standards adopted by the tear or intergranular separation are not allowed in the case of 40 times magnification. Pipe bending radius is controlled by the composition of the alloy, the general minimum bend radius for 2d. Conditions of the welding seam in a neutral or a state of compression. Moreover, the piping should be annealed to reduce its hardness, thereby improving the bending performance. Cost and prices: Usually the titanium seamless pipe cost is higher than titanium welded pipes, because the raw material, manufacturing equipment and processes. But sometimes by the market pressure, titanium welded pipe is more expensive, so if you met this situation, don’t hesitate to purchase the titanium seamless pipe for the same dimensions. Wall thickness and diameter: thickness and diameter value of small thin-walled pipe preferably by welding production. Thickness and diameter large thick-walled pipe is best made with the stamping method.