Application and analysis of stainless steel welded pipe in different industries

Stainless steel welded pipe is an important field of deep processing of stainless steel plate / strip, and also the main material for oil, chemical, medicine, food and laying corrosion-resistant pipes. It is the main component of power generation equipment, ship industry, refrigeration equipment and desalination equipment. Therefore, stainless steel welded pipe is more and more concerned by users and the attention of relevant departments.

The main characteristics of stainless steel welded pipe production are: light production equipment, less investment, fast construction speed, simple welding method, wide range of product specifications, high dimensional accuracy, small deviation of wall thickness, smooth surface and high yield. In the case of mass production, the cost of welded pipe is more than 20% lower than that of seamless pipe. In recent years, the domestic production technology of “welding cold rolling” and “welding cold drawing” has been used to produce stainless steel pipe. After the cold rolling sheet is cut and formed according to the specification, it is welded into a pipe by multi gun argon arc welding machine, and then cold rolled (drawn), so that the performance indexes of the weld can be basically consistent with the base metal and the product quality is obviously improved. Therefore, the advantages of replacing stainless steel seamless pipe with stainless steel welded pipe are more and more obvious.

The general situation of stainless steel welded pipe industry in China

With the rapid development of China’s economic construction, the consumption of stainless steel is increasing, and the demand of stainless steel pipe is also increasing, and the market prospect is good. The market demand of stainless steel seamless pipe is shown in the basic industry, such as petroleum, chemical industry, power generation, etc., which accounts for two thirds of the total consumption of stainless steel seamless pipe, and there are also large demands for automobile, shipbuilding, construction and environmental protection industry. Stainless steel welded pipe is mainly used in urban landscape and construction decoration industry, with annual consumption of 700000 t. The requirements of industrial stainless steel welded pipe are relatively high, and the production process is not mature. At present, the annual production of industrial stainless steel welded pipe in China is about 150000 tons, most of which need to be imported.
From the domestic stainless steel pipe products, the steel has developed from single austenite steel to martensite and ferritic steel, duplex steel and high alloy steel. The products include: seamless steel pipe includes cold drawing pipe, cold rolled pipe, hot extrusion pipe, centrifugal casting pipe and spinning pipe; welding pipe includes: isoionic welding, argon arc welding, submerged arc welding, light speed welding and high frequency welding, etc., and the welding pipes can not be produced The stainless steel pipe basically covers the specifications of the world standard, and the stainless steel special-shaped pipe specifications and varieties also reach more than 100 kinds. The product uses in many fields of industry and civil. But in general, the domestic stainless steel pipe has a certain gap with the market demand in terms of variety, specification, quantity and quality
In terms of the products and quantity of stainless steel pipes: the production of general purpose stainless steel pipes has been balanced with the overall market demand. The production capacity of seamless pipe is larger than market demand and production is excessive; the market supply of stainless steel decorative welded pipe with medium and low-grade standards is more than demand; the production capacity of high standard industrial welded pipe is insufficient, especially the high-demand industrial pipe, such as high pressure stainless steel boiler pipe for power station, etc.
In terms of the specification of stainless steel pipe products: the production capacity of medium and small-sized stainless steel pipes for general use is large and dry market demand; for large-diameter and high-demand stainless steel pipes, the market supply is short of demand and the gap is large. For example, the large diameter stainless steel pipe with diameter of over Φ 21mm needs to be made up for the shortage by import. Moreover, for the super long pipe with the length of more than 15m, there is little production in China, which is basically imported.
In the stainless steel pipe variety: at present, the foreign widely used 304L, 316L and other ultra-low carbon stainless steel. The domestic urea grade and high precision stainless steel has difficult quality assurance; some special stainless steel pipes with high technical difficulties and high quality requirements, such as heat exchanger pipe of power plant boiler, urea pipe for fertilizer plant and oil well pipe, are mainly imported; some duplex stainless steel pipes with good corrosion resistance are rarely produced in China and cannot meet the market demand.

From the production of stainless steel pipe: in recent ten years, with the rapid expansion of application field and the attraction of high added value of stainless steel pipe, the enterprises producing stainless steel pipe have developed from more than ten enterprises in 1980s to more than 400, with comprehensive production and processing capacity of more than 1 million tons. There are nearly 300 stainless steel seamless steel pipe manufacturers, with a production capacity of 500000 in 2007, and above, stainless steel welding The annual production capacity of the production line is over 800000 tons, which is larger than the demand. There are few enterprises with an annual output of 5000t, most of which are small plants with an annual output of less than 2000t. The production capacity of stainless steel welded pipe for industrial use in China is not suitable for the domestic market demand. Most of the existing stainless steel pipe welding pipe units are not matched with each other, such as lack of heat treatment and online testing equipment, which makes the production capacity of the unit not fully exerted, and generally only the general decorative pipe can be produced, while only a few manufacturers have high requirements for chemical machinery pipes and heat exchanger pipes It can be produced.

Super ferritic stainless steel welded pipe

Under the condition of brackish water and polluted sea water as cooling medium, the corrosion resistance of copper and copper alloy tubes as condensing tubes can not meet the requirements. With the progress and development of metallurgical technology, high performance stainless steel welded pipe and titanium welded pipe are effective ways to replace copper alloy condenser tube. At present, the selection of condenser tubes for power plants in China is carried out according to the requirements of DL / t712-2000 “guide for material selection of condenser tubes in thermal power plants”. Under the condition of seawater as cooling medium, welded tubes HAl77-2, BFe30-1-1 and TA1 can be selected. Different grades of high performance stainless steel tubes have been widely used in condenser tubes of coastal power stations in the world. According to the “guidelines for the use of stainless steel in chloride ion water” of the United States, in addition to titanium, high-performance austenitic stainless steel (such as AL-6XN, 254SMO) and high-performance ferritic stainless steel (such as al29-4c, sea-cure) are also suitable for seawater cooling. These materials can operate in seawater from the perspective of corrosion resistance.
In the United States, high-performance austenitic stainless steel welded pipe was first used in Power Station Condenser since 1973. Before 1979, high-performance austenitic stainless steel welded pipe was basically used. High performance ferritic stainless steel welded pipe has been used in Power Station Condenser since 1979. Although the share of high performance ferritic stainless steel welded pipe is not large in the following years, its growth rate is relatively fast. After 2000, high-performance austenitic stainless steel welded pipe is basically no longer used, and the use of high-performance ferritic stainless steel welded pipe, since 2003, in the actual cumulative amount of use, high-performance ferritic stainless steel welded pipe also exceeds high-performance austenitic stainless steel welded pipe.
The properties of ferritic stainless steel and austenitic stainless steel are compared as follows:
Elastic modulus: high performance ferritic stainless steel is slightly larger than high-performance austenitic stainless steel, so the seismic performance of high-performance ferritic stainless steel is slightly stronger than that of high-performance austenitic stainless steel, thinner pipe wall can be used without vibration, and thin-wall is more conducive to heat transfer.
Thermal conductivity: high performance ferritic stainless steel is larger than high-performance austenitic stainless steel, so the heat transfer performance of high-performance ferritic stainless steel is better than that of high-performance austenitic stainless steel.
Linear expansion coefficient: high performance ferritic stainless steel is closer to the linear expansion coefficient of carbon steel than high-performance austenitic stainless steel. Therefore, high-performance ferritic stainless steel has less internal stress due to thermal expansion, and the peeling or cracking tendency of surface oxide film caused by thermal expansion coefficient difference is small, which is more suitable for high-temperature cyclic oxidation environment.
Density: high performance ferritic stainless steel is smaller than high-performance austenitic stainless steel. Under the same volume condition, the weight of high-performance ferritic stainless steel is lighter than that of high-performance austenitic stainless steel.
These two types of high performance stainless steel welded pipes have excellent corrosion resistance to various types of corrosion, such as chlorine pitting, steam erosion, stress corrosion, marine biological corrosion, etc. Therefore, both types of high performance stainless steel welded pipes can be used in the condenser of coastal power station (including polluted seawater).
The specific corrosion resistance test shows that sea-cuer has better chloride corrosion resistance and sediment erosion resistance than high-performance austenitic stainless steel (AL-6XN).
Super ferritic stainless steel has excellent comprehensive properties, and has been widely used in the United States and other countries, and has a good prospect in China.

Application analysis of stainless steel welded pipe in heat exchanger of different industries

Super ferritic stainless steel pipe has not been put into use in China. From the perspective of application, it is mainly used in power plant condenser in the United States, and it is also widely used in heat exchanger of chemical plant. As a new alternative product in China, we mainly introduce the application of condensing tubes in chloride ion water, such as titanium tubes, copper alloy tubes and other types of stainless steel tubes

Power plant condenser

As a basic energy industry, China’s power industry will continue to grow in the next few years. In terms of the total domestic installed capacity from 2003 to 2006, thermal power accounted for about 75%, as shown in Table 1.

	2003	2004	2005	2006
New installed capacity	3000	5055	6602	10097
Including: thermal power	2433	3917	5464	9028
Hydropower	882	1157	1896	971
Total installed capacity	39015	44239	50841	66200
Including: thermal power	28977	32984	38413	48405
Hydropower	9489	10524	12426	12857

According to the national “Eleventh Five Year” electric power development plan and the long-term plan to 2010, coal-fired thermal power is still the main component of the installed capacity of power generation. In 2010, the installed capacity of coal-fired thermal power will reach 477.3-503.3 million KW, accounting for 68.2% – 68.9%. During the “Eleventh Five Year Plan” period, China will increase 140 million KW and 160 million KW. By 2020, the installed capacity of coal-fired thermal power will reach 710 million-785 million KW It is estimated that about 30 million kw of new thermal power units will be added in this year. According to the national requirements for the construction of power supply thermal power units, the installed capacity of a new coal-fired power plant must reach 300MW, and the unit specially used for power supply should reach 600MW. Therefore, it can be approximately considered that 50 600MW thermal power generating units will be built every year in the future, which is equal to 25 new 600mwx2 thermal power projects. At the same time, according to the “11th Five Year” power planning and long-term planning of coastal provinces (including Guangxi, Guangdong, Fujian, Zhejiang, Jiangsu, Shandong, Liaoning, etc.), about 10 coastal thermal power plant projects of 600mwx2 are constructed each year, accounting for 40% of the thermal power projects invested in construction each year.
As a clean energy, nuclear power has shown a strong development trend in China in recent years. See Table 2 for the medium and long term development plan of nuclear power (2005-2020).

Table.2 schedule assumption of nuclear power construction project (unit: 10000 kW)

	Scale of new construction in five years	Scale of production in five years	Next five years	Total scale of nuclear power operation at the end of five years
Scale before 2000	226.8
During the 10th Five Year Plan	346	468	558	694.8
During the 11th Five Year Plan Period	1244	558	1244	1252.8
During the 12th Five Year Plan Period	2000	1244	2000	2496.8
During the 13th five year plan	1800	2000	1800	4496.8

According to table 2, during the period from the 11th five year plan to the 13th five year plan, China will start construction of 50.44 million KW nuclear power units in total, and 3.36 million KW nuclear power units will be built each year, which is similar to the annual addition of 6 600 MW nuclear power units and the construction of three 600 mwx2 nuclear power projects.
For a long time, copper and copper alloy tubes have been the preferred materials for the heat exchange tubes of power station condensers. The practice shows that copper alloys have excellent service performance in fresh water and clean seawater. But at the end of 1950s, due to the rapid development of petroleum, chemical industry, papermaking and other industries, a large number of industrial wastewater, urban sewage and organic matter were discharged, which seriously polluted the seawater in the river, river mouth and the Bay around the city. As a result, serious corrosion and leakage occurred in the condenser cooling pipe of Binhai power station with copper (BFe30-1-1) pipe, which could not meet the requirements of power station operation.
In recent years, with the increase of stainless steel pipe production and the maturity of pipe welding technology, stainless steel pipe with thin wall, large heat exchange area and high strength has become the main competitor of copper tube used as condenser material in thermal power plant. At present, stainless steel condenser tubes have been basically used in new units with thermal power generation capacity of more than 300000 kW. In some areas with poor water quality, such as coastal areas where seawater is used for cooling, titanium tubes with high cost and large one-time investment are basically selected to replace copper alloy tubes for new power plants. Because nuclear power plants are basically built in the seaside, seawater is used as the cooling medium, and titanium tubes are basically used as condenser tubes at present.

Petrochemical Industry

Heat exchange devices are widely used in petrochemical industry, such as the heat exchange tubes used in atmospheric and vacuum distillation units and hydrocracking units in the oil refining industry, heat exchangers for offshore oil platforms, water treatment and water supply systems, fire protection systems, water spray systems, water stabilization systems, etc. in the petrochemical industry, the heat exchangers of polyvinyl chloride, coil type oxychlorination reactors in vinyl chloride plants, and methanol synthesis reactors are used in petrochemical industry Stainless steel pipes are widely used in the production of organic acids (formaldehyde and formic acid) such as acetic acid, material / effluent heat exchanger, condenser on top of medium pressure flash tank, etc. In petrochemical industry, due to the wide range of operating temperature, it can reach – 196 ℃ at low temperature and above 500 ℃ at high temperature; the operating pressure includes external pressure, vacuum, atmospheric pressure, medium pressure, high pressure and ultra-high pressure (dry 100MPa); the medium in the operating environment is complex, such as corrosive, abrasive, flammable, explosive, toxic and other solid, gaseous, liquid and various mixed media chlorination Therefore, when stainless steel is used in petrochemical industry, it is required to have strong corrosion resistance (including chloride, sulfide and other salt corrosion) and high and low temperature resistance.
At present, austenitic stainless steel is mostly used in petrochemical industry, among which 304 grade stainless steel plate, tube and forging are the largest, 316, 304L, 316L plate, tube and forging are in large amount, and the consumption of boiler tube and heat exchanger of TP304H, TP347H and super310s in ASTM standard is also increasing gradually. In addition, duplex stainless steel has been rapidly popularized and applied in petrochemical industry due to its special corrosion resistance, and the amount of duplex stainless steel pipe is gradually increasing. At present, the consumption of stainless steel welded pipe is about 15000t.

Seawater desalination

In recent years, the situation of fresh water resources in China is not optimistic. The water shortage in normal years is about 40 billion m3. Among the 660 cities in China, more than 400 cities are short of water, of which 108 are seriously water deficient. However, China has a coastline of nearly 20000 km and is rich in sea water resources. Therefore, the state has listed seawater desalination as “the current high-tech industrialization key field guide” to cope with the increasingly tense supply of fresh water, which makes desalination and its equipment production increasingly become a hot industry. In 2005, the national development and Reform Commission, the State Oceanic Administration and the Ministry of Finance jointly issued the “special plan for seawater utilization” and put forward the development goals.
At present, the commonly used desalination methods in the world include distillation, reverse osmosis and electrodialysis. Distillation method is generally used for seawater fresh water technology with daily treatment capacity of more than 3000t. It is estimated that about 300t copper alloy tubes are needed as condenser tubes in desalination equipment with daily treatment capacity of 10000 tons, with specifications of Φ 19mm, Φ 20mm, Φ 25mm and Φ 32mm, and thickness of 0.75-1.0mm. Among them, the condensing tubes used in the multi effect flash method (MED) are nickel white copper alloy tubes with a length of about 18 m; the condensing tubes used by the multi-stage flash evaporation method (MSF) are aluminum brass alloy tubes with the length of about 3-4 m and 7-8 M.
After more than 40 years of development, China has become one of the few countries in the world to master the advanced technology of seawater desalination after the United States, Japan and South Korea. Especially, it has rich engineering practice and technical experience in the two major technical fields of distillation and reverse osmosis, and has a certain foundation and scale at present. In 2003, about 33 billion m3 of seawater was used as cooling water for power, petroleum, chemical and other industries in China. The output of seawater desalination that has been completed and put into operation is about 31000 m3 / D (the output of brackish water desalination is 28000 m3 / D), and the scale of projects under construction and to be built is 381000 m3 / D. in 2005, the daily output of seawater desalination has increased to 100000-150000 t. In order to achieve the development goal proposed in the special plan for seawater utilization, according to the target of 2010, that is, 800-1 million tons / day of seawater and fresh water treatment capacity, China needs to add 200000 tons / day of fresh water every year in the next few years. If the distillation method is adopted for 50% of this amount, about 3000 tons of copper alloy condenser tubes will be needed in the seawater desalination equipment every year. At present, in developed countries, super ferritic stainless steel tubes have been used instead of copper alloy tubes as condenser tubes.

Shipbuilding

Condenser tubes for ships and large oil tankers are another important application field of copper alloy tubes. The main copper alloy condenser tubes for ships are BFe30-1-1, bfel0-1-1 white copper tubes, HSn70-1 tin brass tubes and HAl77-2 aluminum brass tubes. As an important tool for crude oil transportation, the function of oil tanker is to transport crude oil from the place of origin to another place with refining capacity. Due to the high viscosity of crude oil and sometimes very low sea temperature, the crude oil needs to be heated for export. Therefore, the heat exchange pipes are laid at the bottom and four walls of the oil tank according to the calculated necessary heat exchange area. Due to the fact that seawater is the medium to realize heat exchange at sea, it is required that the pipes have excellent seawater corrosion resistance and high mechanical and technological properties. Most of these pipes are made of aluminum brass tubes with large specifications, especially those used for connecting parts. For example, the specification of common heating pipe is Φ (42-44) inttlx2mmx6000mm, and the specification of side connecting pipe is Φ (24-56) mmx6000mm.

With the improvement of technical management level, labor and raw material cost advantages and strong industrial support policies of Chinese shipbuilding enterprises, the global shipbuilding industry is accelerating its transfer to China. The share of China’s shipbuilding industry in the world market has also increased from 3% at the beginning to 32% at present. The average annual growth rate of shipbuilding production is as high as 40%, as shown in Table 3.

Table.3 China’s shipbuilding completion from 2003 to 2006

	2003	2004	2005	2006
National Shipbuilding completion (10000 DWT)	605	855	1212	1452
New orders of 10000 tons	1850	1579	1699	4251
Hand held ship order (10000 DWT)	2659	3359	3963	6872
Export amount (US $100 million)	30.22	31.6	46.6	81.8

About 20 kinds of copper and copper alloys have been used in ships, and the amount of copper and copper alloys is increasing gradually. On general military and commercial ships, the amount of copper and copper alloy can account for 2% – 3% of the ship’s weight. Among them, the copper alloy condenser tube is the largest in China’s shipbuilding industry, about 60000 tons per year. In recent years, with the improvement of metallurgical technology, copper alloy pipe used in shipbuilding industry is being replaced by stainless steel pipe.

Other industries

Automobile industry

China’s automobile industry is booming. Enterprises engaged in the development and application of stainless steel attach great importance to stainless steel used in automobiles. The average stainless steel used for each vehicle is 24-30kg / set, of which 5-8KG is stainless steel welded pipe, which is mainly used in ternary purifier, exhaust pipe, air conditioner and water cooling box. In 2008, China produced 9.6 million cars and consumed 50 000 tons of stainless steel welded pipe.

Electronic instrument industry, etc

About 5000 tons of stainless steel tubes are needed in electronic, instrumentation, metallurgy and other industries every year. It is used for equipment manufacturing and maintenance in light industry such as beverage, wine, food, textile, printing and dyeing, etc., and medical and pharmaceutical industry, with annual consumption of stainless steel pipe of more than 30000 tons. Many stainless steel pipes can be welded.

Water supply industry

In recent years, some cities in China have begun to use stainless steel pipes in the transportation of water and gas. Stainless steel pipeline and water conveyance equipment are the most advanced basic water purification materials in the world, and their corrosion resistance is strong, which can not be compared with cast iron pipe, carbon steel pipe and plastic pipe. After using stainless steel pipe as water transmission pipeline in Japan, the water leakage has been reduced from 15% to about 7%, and the water quality has been greatly improved. Wuhan has invested a lot of money to widely use stainless steel pipes and equipment. In a possible short period of time, stainless steel pipes will be used for water supply in new high-rise residential buildings and office buildings. Some residents in Ningbo, Daqing and other places have begun to use stainless steel pipes for water supply.

Analysis of ferritic stainless steel welded pipe

Comparison between super ferritic stainless steel pipe and competitive materials

We compare super ferritic stainless steel pipe with competitive materials such as titanium pipe, 317L welded pipe, 316L welded pipe and naval copper alloy pipe, as shown in Table 4.

Table.4 Comparison of super ferritic stainless steel pipe and competitive materials

	Specifications		Price (10000 yuan / T)	Proportion	Substitution coefficient of dosage	Overall substitution coefficient (including price)
Titanium pipe	Φ25×0.5		55	4.51	1	1
317L stainless steel welded pipe	Φ25×0.6		13	7.7	1.71	0.484
316L stainless steel welded pipe	Φ25×0.6		8	7.7	1.71	0.298
Navy copper alloy pipe	Φ25×1		7	8.9	3.95	0.538
Super ferritic stainless steel welded pipe	Φ25×0.6		6.15	7.7	1.71	0.558

It can be seen from table 5 that super ferritic stainless steel tubes as condensing tubes have relatively large price advantages over titanium tubes and can be recognized by users under the same performance conditions. At present, titanium tube condenser market can be used as the target market of super ferritic stainless steel welded pipe.
Although the price of super ferritic stainless steel pipe is slightly higher than that of 317L stainless steel pipe, the advantages of stress corrosion resistance such as chloride ion can offset this part of price factors, and can be used as a potential alternative market.
The condenser tubes used in clean seawater, such as desalination and shipbuilding, are still copper alloy tubes market. However, due to the continuous rise of copper price, from 15000 yuan / T in 2000 to 70000 yuan / t now, it is not competitive compared with stainless steel tubes in cost performance. It can be predicted that stainless steel tubes will be gradually replaced in the fields of seawater desalination and shipbuilding in the near future Copper tubes, desalination and shipbuilding will be the potential market for super ferrite and duplex stainless steel tubes in the future.

Application prospect of super ferritic stainless steel welded pipe

From the perspective of market situation, the use of super ferritic stainless steel pipe in China has just begun. From the perspective of the use situation in the United States, the super ferrite stainless steel welded pipe is mostly used in power plant condenser, and it is also widely used in chemical heat exchanger.
At present, titanium tubes are mostly used in the condenser tubes of coastal power stations and nuclear power stations in China. In petrochemical industry, titanium tubes are often used in heat exchange equipment of petrochemical industry when seawater is used as cooling medium or in working environment with high chloride ion content. In these two fields, super ferrite stainless steel pipes can be used as their obvious target market. In the field of seawater desalination and shipbuilding, seawater is used as the condensing medium, and the number of condensing tubes is large, which can be used as the potential market of super ferritic stainless steel tubes. It can also be used as a potential market for automobile manufacturing, electronic instruments, metallurgy, textile, printing and dyeing. For other fields, such as chemical fertilizer industry, although there is a large demand for stainless steel tubes, high-performance stainless steel tubes require a variety of specifications and steel grades; the batch size is small, and the possibility of substitution is small. Although there may be a large amount of stainless steel pipe used in water supply industry, the ordinary 304 steel pipe can meet the requirements. Affected by the price, it is unnecessary to use high-performance super ferritic stainless steel pipe.

Condenser tube for condenser of newly built power plant by the sea

According to the 11th Five-Year Plan and long-term plan of coastal provinces, about 10 coastal thermal power plants with 600mwx2 will be constructed each year. According to the current condenser design and material selection requirements, titanium tubes are basically used as condenser tubes in these power plants. If 80 t titanium tubes are used for condenser of each 600MW thermal power unit, about 1600t/a titanium tubes are required. If super ferritic stainless steel tube is used, each 600MW thermal power unit condenser needs 140t, and the total demand is 2800t/a.
Each year, six 600 MW nuclear power units will enter the construction period. All nuclear power projects are built on the seaside, which requires a large amount of seawater as the condensation medium. Titanium tubes are basically used as heat exchange tubes on the condenser. If 80 tons of titanium tubes are required for each 600 MW unit, about 480 tons of titanium tubes are needed each year. If super ferritic stainless steel pipe is used, 840t/a is needed.
The total amount of titanium tubes used for condensers in Shanghai thermal power plant and nuclear power plant is about 2080 tons per year. If super ferritic stainless steel tubes are used, it will take 3640 tons / A. (the titanium tube is calculated as 025×0.5, and the super ferrite stainless steel pipe is calculated as 025×0.6).

Retrofit of condenser in existing seaside power plant

Although titanium tubes are used as condensing tubes in the condensers of domestic built coastal power plants, due to the introduction of some foreign units in the 1990s, the original design is adopted, and copper tubes are used as condensing tubes. Under the current situation of seawater pollution, the corrosion protection performance can not meet the requirements, and frequent leakage occurs, which affects the normal operation of the units. Therefore, this part of the power plant for condenser transformation is very urgent, such as Yingkou Power Plant, Suizhong Power Plant and so on. In addition, due to the state’s control over the use of clean water sources such as groundwater and reservoir water, some inland power plants will also use seawater as cooling water source, and some power plants in the mainland will switch to urban reclaimed water as cooling water source. These power plants will change the condenser pipes and generate a certain market demand. Overall, it is estimated that about 3 million KW units will be retrofitted each year, resulting in annual demand of 700 tons of super ferritic stainless steel pipes.

Heat exchange tube for chemical industry

About 5000t stainless steel welded pipes are used in petrochemical industry every year, of which 30% are used in heat exchangers, and 40% are expected to use high-performance stainless steel pipes. In addition, 1000t titanium pipes are used annually in chlor alkali industry, which are mainly used in heat exchangers containing chloride ions. If super ferritic stainless steel is used to replace these two parts of condenser tubes, it will need 3700 t/a.
From the above, the demand of super ferritic stainless steel pipe in new power plant condenser and old power / condenser reconstruction is about 40t/a, the total demand of chemical industry is about 3700t/a, and the main competitive product is titanium pipe.

Potential market

From the performance of super ferrite stainless steel pipe and the use of stainless steel pipe, the pipe for condenser, automobile manufacturing, desalination and ship manufacturing in inland power plant can be regarded as the potential market of super ferrite stainless steel pipe.

Pipe for condenser of inland power plant

At present, the condenser of new units with thermal power generation of more than 300000 kW has basically used stainless steel condensate pipe, which accounts for 70% in the thermal power industry, mainly used in inland areas, with materials of 316L and 317L. 60% of the 30 million KW new fire motor units are added in the inland area each year, with the total added amount of 18million kW. According to the calculation of the power plant adopting 317L pipe as condenser pipe, the 317L stainless steel pipe 2520t/a is needed. After the production cost of super ferrite stainless steel has decreased, it can be used as an alternative product of 317L.

Desalination of seawater

From the market, the copper alloy pipe will be needed for seawater desalination in China. The price of copper nickel alloy pipe is still high because of the continuous increase of copper price and nickel price. In order to have a good corrosion resistance effect on chloride, the nickel content in copper alloy pipe reaches 22%, and the market price of such copper tubes reaches nearly 100000 yuan / T. moreover, the copper alloy pipe generally adopts 1mm wall thickness, which is much larger than 0.6mm of super ferritic stainless steel pipe, and the cost estimation is also close to that of the steel pipe. If the national standards and design conditions change, the super ferrite stainless steel pipe will be made of It is an alternative to copper alloy tube.

Air conditioning

Air conditioning is an industry related to people’s lives. In 2008, the output of domestic air conditioning in China was 24.3 million. Copper pipe was used for air conditioning pipes. The diameter of the pipe was generally Φ 6-10 mm and the wall thickness was 0.4-0.7mm. When the processing performance of ferrite stainless steel was improved, stainless steel pipes with wall thickness of 0.1 and 0.15mm and diameter of Φ 6-012mm could be produced. The service life was extended and the heat exchange efficiency was improved. It was a heavy duty for energy saving, environmental protection and air conditioning cost reduction To measure, according to the average use of 2kg / set of air conditioning, it is about 48600t per year. Therefore, the development and production of air conditioning pipe is also an important project worth the research and development of welding pipe manufacturers.

Sugar making, pharmaceutical, dairy production and brewing industry

The demand for stainless steel pipe in sugar making, pharmaceutical, dairy production and brewing industry is about 30000 tons a year. The manufacturing process of stainless steel pipe has been improved, and the welding seam rolling is realized. The internal quality and the internal and external surface quality can meet the requirements of sanitary grade pipes.
There are still many stainless steel tubes used in the industrial field that have not been studied in depth, and the amount of this aspect cannot be clarified. For example, the new energy industry, solar energy industry, communication industry, storage industry, heating and general industry driven by the development of heat pump technology can definitely be a huge potential market.
From the above, there is a huge potential market for industrial stainless steel welded pipe, and it needs to be further developed.

Source: China Stainless Steel Welded Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.epowermetals.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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