ASTM A312 347 / 347H ERW Welded Pipe with Woven Bag Packaging for High-Temperature Piping Systems

ASTM A312 347 / 347H welded pipe

ASTM A312 347 / 347H welded pipes are made of stabilized austenitic stainless steel with niobium (Nb) added to improve resistance to intergranular corrosion, especially for high temperature service environments. 347 is suitable for conventional high temperature corrosion scenarios, while 347H has stronger high temperature creep strength due to its higher carbon content, suitable for high temperature pressure vessels, boilers, heat exchangers and other equipment. This material has excellent welding performance and corrosion resistance, and is often used in industries such as petrochemicals, electric power, aerospace, etc. that require high temperature structural stability.

How 347 / 347H Welded Pipe used in High-Temperature Piping Systems

347/347H welded pipes are widely used in high-temperature piping systems due to their excellent high-temperature resistance and resistance to intergranular corrosion. This type of pipe is often used in high-temperature and high-pressure environments such as petrochemicals, refineries, and boiler systems, and is particularly suitable for equipment that requires long-term stable operation. 347 pipes have a lower carbon content, which reduces intergranular corrosion in high-temperature environments, while 347H has a higher carbon content and has stronger high-temperature creep strength, making it suitable for applications under higher temperatures and more demanding conditions.

This type of pipe is often used in systems such as heat exchangers, steam pipes, and heating furnaces. It can withstand the transmission of high-temperature gases and liquids while ensuring the strength and corrosion resistance of the pipe at high temperatures. Due to its strong stability, 347/347H welded pipes are an ideal choice for handling high-temperature media and are widely used in industrial piping systems that require high-temperature resistance and corrosion resistance.

Parameter table:

Chemical Composition：

Physical Properties：

ERW welding method introduction:

ERW (Electric Resistance Welding) is a commonly used welding pipe forming process, which is widely used in the production of stainless steel and carbon steel welded steel pipes. This process applies high-frequency current to the edge of the steel strip, so that it is quickly heated to a molten or plastic state under the action of resistance, and then welded by upsetting pressure. The whole process does not require the addition of welding materials, the weld is narrow, and the welding heat-affected zone is small, which effectively maintains the mechanical properties and corrosion resistance of the parent material.

The ERW welding process has the advantages of high efficiency, good dimensional consistency, and fast forming speed, and is especially suitable for small and medium-caliber and large-scale production needs. Compared with traditional manual welding or submerged arc welding, the surface of ERW welds is smooth and easy to process later, which can meet the high standards for the appearance and precision of pipes in industrial fluid conveying systems, heat exchange equipment, building structures, automobile manufacturing, petrochemical systems, etc.

In the production of stainless steel welded pipes, common austenitic stainless steel materials such as TP304, TP316L, TP321, TP317L, etc. are suitable for ERW forming. For ERW stainless steel welded pipes that meet international standards such as ASTM A312, solid solution heat treatment and non-destructive testing are usually required to ensure that the weld area has the same mechanical properties and corrosion resistance as the parent material, so that it is suitable for engineering applications in high temperature, high pressure or highly corrosive environments.

Quality control method：

Secondary inspection of raw materials

The raw materials used by MTSCO are all from well-known Chinese steel mills, such as Baosteel, Qingshan, TISCO, Dongfang Special Steel, etc., to ensure reliable quality. Each batch of raw materials must provide a material certificate (MTC) and PMI (spectral analysis) report. After the raw materials arrive at the factory, we will also conduct a secondary PMI test to ensure that they fully meet the production requirements and eliminate the risk of unqualified raw materials.

Production management with traceability throughout the process

MTSCO's welded pipes are mainly formed by rolling (RBE) and bending, using PAW+GTAW automatic welding process to ensure full weld formation and stable quality. We have upgraded the technology based on traditional processes, especially for large-diameter thick-walled welded pipes. Problems such as out-of-round welds have been optimized. At the same time, a 12-meter-long annealing furnace is used for solid solution treatment to make the annealing effect more uniform and thorough. The production process is supervised by experienced engineers and quality inspectors throughout the process. Each process is recorded and photographed for archiving, and the whole process is traceable in combination with the process flow card.

100% quality inspection before leaving the factory

Before leaving the factory, MTSCO conducts a comprehensive quality inspection on each welded pipe, including basic inspections such as appearance, size, quantity, PMI, as well as mechanical property testing, hardness testing, X-ray flaw detection, ultrasonic testing (UT), eddy current testing (ET), water pressure testing, etc. The maximum supported water pressure test is an outer diameter of 630mm, and the weld part is 100% X-ray non-destructive testing. We also support the verification of third-party testing agencies such as SGS, TUV, BV, etc. to ensure that each batch of products is of reliable quality and meets the standards.

Factory advantages and features:

Investing in Huxin Pipe, a factory with 36 years of pipe-making expertise, MTSCO has become a highly reliable manufacturer of welded pipes. This strategic partnership ensures the delivery of top-notch welded pipes backed by decades of industry experience.

The welded pipes from MTSCO come in a variety of sizes, with diameters reaching up to 3 meters, and hydrostatically tested pipes available in sizes up to 1.5 meters. This diversity in size caters to a wide range of industrial applications, providing flexibility to meet specific project requirements.

Equipped with state-of-the-art production and inspection equipment, including a CNC bending machine, plate shearing machine, 12m annealing furnaces, pickled pool, ultrasonic eddy current integrated machines, and a physical and chemical lab, MTSCO ensures a comprehensive manufacturing process. The bending machine, with a maximum thickness capacity of 60MM and a length of 12 meters, adds to the precision and versatility of the production process.

To guarantee the quality of the welded pipes, MTSCO has implemented a complete quality control process. Full-time quality inspectors from MTSCO supervise the entire production process before, during, and after manufacturing, with the added assurance of 100% filming of all welded pipes.

Furthermore, MTSCO's commitment to quality is reflected in the attainment of various certificates, including ISO/PED/AD2000 certifications. These certifications underscore the adherence to stringent industry standards, providing clients with confidence in the quality and reliability of MTSCO's welded pipes.

Product Packaging：