China titanium welded pipe development history

Titanium and titanium alloy straight seam welded pipe (referred to as "titanium welded pipe") is made by rolling the titanium and titanium alloy coiled strip or wide sheet into a tubular shape and then automatically welded by wire. There are thin wall tubes with a thickness of 0.3~0.9mm and a diameter of 19~100mm, as well as a seamed tube with a diameter of 200 to 1000mm and a wall thickness of 1.5~10mm. The domestic titanium welded pipe grades mainly include TA1, TA2 and TA10, etc. The titanium alloy grades in the United States mainly include Gr.1, Gr.2 and Gr.12.

The production process of titanium welded pipe is as follows: titanium strip unwinding → shear striping → crimped tube shape → welding → weld eddy current flaw detection → predetermined diameter → in-line annealing → fine sizing / straightening → eddy current testing → laser caliper → On-line coding → cut-to-length cutting → ultrasonic flaw detection → fine ruler / flat head → air tightness test → finished product inspection → packaging and storage.

1.the development of domestic titanium welded pipe industry

Before 2000, due to the constraints of titanium belt raw materials and processing technology, the production technology of titanium welded pipe has been in the hands of professional manufacturers in Japan, the United States, France, Russia and other countries for many years. The development of titanium welded pipes in China started relatively late compared to other titanium processed products, and the development in the early stage was relatively slow. Although the titanium seamless pipe started earlier in China, its application has been limited due to the large number of titanium seamless pipe processing processes, long production cycle, low efficiency and high cost. Titanium welded pipe has high production efficiency and finished product rate, and the performance of titanium welded pipe expansion tube and bending is similar to that of seamless pipe. Therefore, the amount of titanium welded pipe at home and abroad is increasing year by year, and its application in power station condenser is increasing.

In the early stage of the development of titanium welded pipe, although China imported a complete automatic production line of small-diameter titanium welded pipe from abroad, it ended the history that China could not produce titanium welded pipe. However, due to the fact that the raw material titanium coils for the production of titanium welded pipes at that time were completely dependent on imports, and the strips for thin-walled titanium welded pipes could not be provided, and the sales price of foreign titanium coils was high, the development of domestic titanium welded pipes was suppressed; Due to the multiple influences of technology introduction and digestion and raw material procurement difficulties, the domestic titanium welded pipe is not really capable of mass production. At that time, the domestic titanium welded pipe market was not really formed.

In the past ten years, the rapid development of China's titanium welded pipe industry, mainly due to the domestic breakthrough in the production technology of titanium welded pipe raw material - titanium coil, the technical performance index, quality stability of domestic cold-rolled titanium coil Can meet the requirements of titanium welded pipe. Since 2007, several large steel mills in China have jointly developed and produced wide-width hot-rolled titanium coils with titanium processing enterprises. In 2008, they developed and produced cold-rolled titanium coils, breaking the monopoly of Japan and the United States in this field. The localization of large-scale titanium belts provided raw material support for the production of titanium welded pipes in China. Subsequently, the production cost of domestic titanium welded pipes fell sharply, fully demonstrating the technical quality and cost advantages of titanium welded pipes, and the market consumption has also been continuously increased. The scale of production has grown considerably.

Baoji Titanium Group successfully introduced the trial production of titanium welded pipe production line in 1988 and built the first titanium welded pipe production line in China. However, at that time, due to the limitation of titanium coil raw materials, the domestic production of large single-weight titanium ring belts, the price of imported titanium belts was extremely high, and the cost of titanium welded pipes remained high. The production of the titanium alloys has not been able to go up for many years, which has become a bottleneck for mass application and promotion. Later, the Baoti Group and several domestic and foreign companies established a joint venture, Xi'an Baoti Meite Ferrino Welded Pipe Co., Ltd., which was officially put into operation in 2007. The production of the production line has promoted the progress of domestic titanium welded pipe production technology. And with the breakthrough of Baoti Titanium Group in cold rolled titanium strip technology, and several large steel companies in China have made substantial progress in the research and development of titanium strip production technology, making the production of large single heavy titanium coils localized, Xi'an Baoti Meite Ferro Welded Pipe Co., Ltd. also realized mass production of domestic titanium welded pipes.

In recent years, with the overall progress of the titanium industry technology, the expansion of sponge titanium production capacity, the expansion of titanium processing materials such as titanium strips, the downstream titanium welded pipe industry has also made considerable progress. Since 2010, several titanium welded pipe production lines have been built in China, and stainless steel pipe production lines in Jiangsu and Hunan have been transformed to produce titanium welded pipes. The rare metal pipe production enterprises have independently launched the titanium welded pipe production line. The investment of these enterprises has greatly promoted the domestic titanium. Progress in the welded pipe industry. However, in the past two years, the expansion of titanium welded pipe production capacity and the slowdown in the development of the titanium industry have also intensified competition among titanium welded pipe enterprises, but many titanium welded pipe companies are paying more and more attention to the development of new technologies and the development of differentiation. Many of the titanium welded pipe products that could not be produced and not produced out of poverty, finding a new way for the development of titanium welded pipes.

With the production process and quality level of domestic titanium welded pipe, the application field of titanium welded pipe is also expanding. Titanium welded pipes have become the preferred corrosion-resistant and lightweight pipe for many industries to replace stainless steel pipes, copper-nickel alloy pipes and titanium seamless pipes. After nearly ten years of development, the domestic titanium welded pipe has broken through the key process and technical bottleneck of the bismuth series. It has been widely used in electric power, air conditioning, seawater desalination, water treatment equipment, etc., and there has also been a good phenomenon of domestic titanium welded pipe bulk export.

2. the comprehensive advantages of titanium welded pipe

Domestically, the production technology of low-strength and low-alloy titanium seamless pipes is relatively mature. In some of the pipes that require high-pressure resistance and structural stress, thick-walled titanium seamless pipes are used. However, due to the low yield of titanium seamless tubes and long lead times, the development of titanium welded pipes has become a trend in the titanium tube industry. Compared with titanium seamless pipes, the comprehensive advantages of titanium welded pipes are becoming more and more obvious. In Japan, the United States, Europe and other countries and regions, the use of titanium welded pipes in some industries is gradually replacing titanium seamless rolling pipes.

a) The mechanical properties of titanium welded pipe and titanium seamless pipe are basically

Taking titanium and titanium alloy tubes for heat exchangers and condensers as an example, the national standard is GB/T 3625-2007, the American standard is ASTMB338, and the difference between chemical composition, mechanical properties and process performance of titanium welded pipe and titanium seamless pipe is different. Not big, even the same. With the advancement of titanium welded pipe welding and heat treatment technology, domestic thin-walled titanium welded pipes generally use single-gun or multi-gun TIG/PAW self-welding welding. After welding, the in-line heat treatment process is adopted. By optimizing the welding and annealing processes, the microstructures of the base metal, weld, and heat affected zone are basically close, and the welding stress is eliminated, and the weld microstructure is uniformized. Through comparison, it is found that the weld composition of the titanium welded pipe is basically the same as that of the base metal, and the mechanical properties and corrosion resistance of the weld are the same as those of the base metal.

b) The appearance and quality of titanium welded pipe is better than titanium seamless pipe

The titanium welded pipe is welded by cold rolling coil, the wall thickness is uniform, the concentricity is good, the smoothness is good, and the pipe is not easy to scale. Especially for thin-walled titanium tubes, production by seamless rolling process cannot meet its technical requirements. Titanium seamless pipes are difficult to achieve a wall thickness of less than 1 mm by rolling or drawing processes; while titanium welded pipes can achieve wall thicknesses of 0.5 mm or less, saving a lot of materials and costs. At the same time, due to the thin wall thickness of the titanium welded pipe, a higher heat transfer coefficient can be obtained, and a better heat transfer effect can be obtained.

c) The cost and environmental advantages of titanium welded pipe are outstanding

The production process of titanium seamless pipe is complicated. Conventionally, a three-roll or multi-roll mill and a drawing machine are used to roll or draw a pipe blank of a predetermined size through multiple passes, and finally a seamless pipe is produced after reducing the diameter and reducing the wall. . The process has low production efficiency and low yield. Titanium seamless pipe from titanium sponge to pipe, through rolling or drawing, material waste is large, the finished product rate is only about 50%, and large-scale mass production cannot be achieved, and the production cycle is relatively long.

The titanium welded pipe is produced by an automatic continuous production line, which is formed by cold-bending forming, welding, on-line heat treatment, sizing straightening, non-destructive testing and air tightness testing using a titanium strip with uniform wall thickness. From titanium sponge to welded pipe, the material utilization rate is usually about 80%. If the titanium tape is used as the raw material, the material utilization rate is above 95%. With the rapid development of the domestic titanium industry and the maturing of welding technology, the production efficiency of titanium welded pipes will be greatly improved, and the quality stability, cohesiveness and production efficiency will be higher. It can be cut to the required length according to the customer's requirements, the delivery time is short, the material utilization rate is high, and the unit cost is lower than the seamless pipe.

Titanium seamless pipes are usually produced by processes such as rolling or drawing. A large amount of rolling oil, drawing oil, etc. will be used in the production process, and the production site is seriously polluted. After the titanium tube is rolled and drawn, the grease and dirt on the inner and outer surfaces of the pipe need to be degreased and pickled, and the pickling process is highly polluting to the environment. In order to ensure the health of the operators and protect the environment, it is necessary to increase the protective equipment and protective measures, thus increasing the capital investment and the production cost of the products. The titanium welded pipe is continuously mass-produced through an automated production line, with stable quality and high production efficiency. In addition to the energy consumption of water and electricity in the production process, there is almost no pollution to the environment.

3. the prospect of titanium welded pipe

With the deepening of people's understanding of titanium welded pipes, coupled with the significant improvement in the production technology and quality level of the domestic titanium welded pipe industry, the rapid development of the titanium welded pipe industry has been promoted. Titanium welded pipes have been widely used in petrochemical, electric power, seawater desalination, water treatment equipment, air conditioning equipment and other industries. The use of titanium welded pipes in the petrochemical industry has been fully recognized by the market, the scope of use is becoming wider and wider, and the market share is also growing. Although titanium welded pipe has higher investment cost than common fluid conveying pipe, its cost is lower than that of titanium seamless pipe, and the investment cost of titanium welded pipe can be compensated in use from the life and maintenance cycle of titanium welded pipe. . The use of titanium welded pipes in piping systems can reduce production costs by reducing the number of periodic maintenance, reducing downtime, improving product quality, and increasing pipeline life. However, titanium welded pipes have also encountered the downturn in the global titanium industry in recent years, and the competition is very fierce. The price of titanium welded pipes is at a relatively low level. This also makes the petrochemical industry enterprises choose the cost of equipment for the early stage of titanium welded pipes. It is also conducive to the continued promotion of titanium welded pipes in the petrochemical industry.

Attn : Jason

Email: jasontitanium@163.com

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