According to the report of the South African Daily News website on March 23, the Department of Trade and Industry of South Africa has formally submitted an application for seeking exemption from steel and aluminum duties to the United States. The ambassador of South Africa to the United States also recently traded to the National Security Council,

A few days ago, the Korea iron and Steel Association said that in February, the stock of cold rolled steel plates in South Korea reached 97 thousand and 400 tons, a decrease of 3.5% compared with the same period, an increase of 25.1% over the same period last year. Generally speaking, the beginning of spring production will lead to the decline of stainless steel stock, but the sales of stainless steel in South Korea will keep warm. The stainless steel production in Korea is expected to be 90 thousand tons ~10 million tons. Therefore, the growth of stainless steel consumption in Korea is basically stagnant. South Korea's stainless steel cold-rolled plate producers and distributors are puzzled.

API 5L seamless steel pipe is characterized by its large diameter and relatively thick wall thickness. Therefore, according to this feature, full use of ultrasonic eddy current detection and internal and secondary surface detection functions are combined to achieve a “no blind spot” test. By adopting the “steel tube rotation and detection probe forward combination”, it not only solves the problem of detection of the title, but also solves the space that occupies a narrow space.

Description of API 5L Seamless Steel Pipe Equipment Oil standard: Hydraulic pressure tester prevents oil corrosion after passing through the steel pipe, and marks according to user's requirements.

The use of spiral steel pipe is relatively high, and the application range is very wide. It should be selected before selection and pay attention to quality. The first method is a more professional method of detection by measuring the strength of the pressure vessel. Normally, we use atmospheric pressure and water pressure detection, which can detect the working conditions of spiral steel tubes working under pressure and detect the tightness of spiral steel tubes. Generally, it is measured at atmospheric pressure because the safety is relatively high, if water is used. Vapor pressure passes the test and then the need for a spiral tube under water is too much trouble. The second method is also relatively simple, that is, through the observation surface. Visually find problems with welding and size of spiral steel tubes, and if necessary, compare standard samples with products to find out where the problem lies. In general, the regular steel pipe company is relatively perfect in production, and on the other hand it is necessary to strike the metal pipe. If the sound is very crisp and the echo is not very dirty, then the name is the latest choice of steel pipe, not scrap recycling. Both methods are commonly used. We can choose one method to test. The safer method is the best regular manufacturer, which can reduce the abuse during use.

The spiral steel strip is formed by spiral bending of a steel strip or a spiral plate and is welded on both sides by submerged arc welding. Steel pipes are widely used in water, electricity, chemical industry and other industries for the following reasons.

In March 26th, the latest data from the World Steel Association showed that India has become the world's second largest producer of coarse steel, with 8 million 430 thousand tons of crude steel in February 2018 and 8 million 300 thousand tons in Japan. In the first 2 months of 2018, the crude steel output in India was 17 million 462 thousand tons, up 2.9% compared to the same period last year, and the crude steel output in Japan was 17 million 321 thousand tons, down 0.1% compared with the same period last year.

In March 23rd, the American steel Society (AISI) report showed that the United States imported 2 million 363 thousand short tons of crude steel in February this year, including 1 million 923 thousand short tons of finished products (18% and 17.6% respectively). The import of crude steel and finished products in the United States were 5 million 245 thousand short tons and 4 million 257 thousand short tons respectively in the first 2 months of this year, down 5.3% and 3.5% respectively over the same period of last year. According to the report, it is estimated that imports of finished products accounted for 24% of the US market share in February this year, and the US market share of imported products accounted for 25% in the first 2 months. The total imports of crude steel and finished products will be 31 million 500 thousand short tons and 25 million 500 thousand short tons in 2018, down 17.5% and 13.6%, respectively. In February this year, the main export products of the US increased significantly, including steel structure profiles (growth of 60%) and wire rod (37%). In the first 2 months, the major products of US imports increased substantially from the same year to year, including hot rolled coils (33%), pipeline (30%) and hot rolled steel (up 27%).

1. Look from the spiral steel pipe. Appearance should pay attention to those welded joints, to see the appearance is not a drawback, the lack of scale, you can see through the naked eye, of course, detailed and bilateral theory, borrow the standard model, gauges and magnifying glass to view. Due to the occurrence of welding defects, this means that the spiral pipe interior is most likely to have defects. Even if the surface efforts are not yet completed, internal efforts are difficult to guarantee.

Spiral steel pipe manufacturing loss rate refers to the spiral pipe in the manufacturing process, raw materials, waste ratio, according to professional and technical personnel for many years of statistical analysis spiral pipe manufacturing loss rate between 2% to 3%.

EFW (Electrofusion Welding) steel tube refers to electron beam welding. For directional impact kinetic energy electron beam, high-speed motion is used to transform the workpiece into a hot workpiece to leave the workpiece to melt and form a weld seam. EFW steel pipes are formed with hot rolled plates and welded welds. The welding flash can be removed from the outside or inside using the enmeshed blade surface. The weld zone can also be heat treated to make the weld invisible. Welded pipes generally have tighter dimensional tolerances than seamless pipes, and if manufactured in the same quantity, the cost is lower. It is mainly used for dissimilar steel welding thin plates or welding with high power density. The metal welding parts can be rapidly heated to high temperature and melt any refractory metals and alloys. The deep penetration welding speed and the heat affected zone are very small, so the impact on the joint performance is small, and the joint is hardly deformed. But it has special welding room requirements because of the use of X-ray welding.

Water pipes AWWA C200 steel pipes are widely used in the following fields/industries: Hydroelectric power station, potable Water supply industry, irrigation pressure pipeline, sewage treatment pipeline

ASTM A520 is a standard specification for the construction of high-temperature boilers for seamless and resistance-welded carbon steel pipe products in compliance with ISO recommended supplementary requirements.

ASTM A500 tube is a standard specification for cold-formed welded and seamless carbon steel structural tubing in round, square and rectangular shapes. ASTM A500 covers cold-formed welded and seamless carbon steel round, square, rectangular, or special shape structural tubing for welded, riveted, or bolted construction of bridges and buildings, and for general structural purposes. This tubing shall be produced in both welded and seamless sizes and must have the chemical requirements of carbon, manganese, phosphorus, sulfur, and copper. Chemical Requirements of ASTM A500

The microstructure of high-frequency straight seam welded pipe welds reflects the welding process performance and welding quality of the steel pipe.

Welding steel pipe slag is the residual slag in the weld. From the theoretical analysis, the main reason for submerged arc welding slag inclusion due to the following three reasons: 1 The raw materials (including the parent metal, wire, and flux) are more tolerable; 2 During the multi-layer welding, cleaning between layers; 3 Improper selection, welding process parameters are not conducive to the production of slag.

In the straight seam steel pipe production of straight seam steel pipe, manufacturers need to have good control of the pressure. This is why during the welding process, the edge temperatures of the two tube embryos reach the welding temperature, and the pressure can make them infiltrate the common metal particles, resulting in a tightly bound crystallization to achieve the purpose of welding firmly. However, if the lack of extrusion during the crystallization process is poor, the strength of the weld seam is very low, and cracks are prone to occur due to external problems during the process. But when the extrusion is too large, the welding temperature of the weld metal will be squeezed out of the weld seam position, R actually welding together can get the temperature and the metal will be very small, so the number of crystals will be reduced, which will also lead to welding Not strong, but there are many glitches, so it is a more serious flaw, so remind consumers to buy straight seam submerged arc welded steel pipe from the regular manufacturers, because they control the extrusion force is perfect.

Thick-walled steel pipe, its pipe diameter and wall thickness ratio of less than 20, said the steel pipe is a thick-walled steel pipe. Mainly used in petroleum geological drilling pipe, petrochemical cracking pipe, boiler tube, bearing pipe and high-precision structural control of automobiles, tractors, aviation and so on.

There are many factors affecting large-diameter high-quality double-sided submerged arc welded steel pipes (DSAW steel pipes). The key factors directly related to the formation of the mass diameter are: expansion rate, axial overlap, number of segments and fillets, friction and lubrication between the block and the inner wall of the steel pipe, shape error of the steel pipe, expansion speed and setting of the expander leveler .

Large-diameter straight seam steel pipe welding, including pre-welding, welding and welding three processes.

At present, the long-distance transportation of oil and natural gas mainly adopts pipeline. Long-distance pipeline pipeline used in the main spiral pipe submerged arc welded pipe(ssaw steel pipe) and double submerged arc welded straight steel pipe(Lsaw steel pipe). As the spiral submerged arc welded pipe is based on strip as raw material, wall thickness is limited, in addition to the existence of spiral submerged arc welded pipe longer, greater residual stress, weld reliability is poor and difficult to overcome the shortcomings of dense population area and reliability requirements of the region, large diameter straight seam submerged arc welded pipe has been gradually replaced by spiral submerged arc welded pipe.