ASTM A789/A790 is an important specification for seamless and welded ferritic/austenitic stainless steel pipes for general use. 31803 Duplex Steel Welded Coil is a high-performance material that has been widely used in modern industry. In order to ensure the quality and performance of these pipes, a series of specific inspection and testing standards and requirements must be followed.

The main chemical components of 31803 Duplex Steel Welded Coil include carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum and nitrogen. The precise ratio of these elements is crucial to the formation and stability of its duplex structure. Its yield strength can reach more than twice that of ordinary austenitic stainless steel, and its good toughness ensures safe use under extreme conditions, making it an ideal material for high pressure and high load conditions.

During the production process, 31803 Duplex Steel Welded Coil needs to go through strict raw material preparation, hot rolling/cold rolling, heat treatment, welding, pickling passivation and inspection. Among them, welding is a key step, and advanced welding techniques such as TIG (tungsten inert gas shielded welding) and MIG (metal inert gas shielded welding) are required to ensure the quality of the weld. At the same time, due to the sensitivity of the duplex structure, excessive heat input may lead to excessive precipitation of the ferrite phase, affecting the performance of the material, so the welding parameters need to be strictly controlled during the welding process.

In terms of inspection and testing, the ASTM A789/A790 standard specifies detailed requirements. First, the product should meet the requirements of the TSG D7002 pressure piping component type test rules. Secondly, multiple inspections including appearance inspection, dimensional measurement, mechanical property testing, water pressure testing, chemical composition analysis, non-destructive testing, etc. are required. Among them, non-destructive testing is a very important means, which can detect potential defects such as cracks and slag inclusions without destroying the material.

For 31803 duplex steel welded coil, non-destructive testing is particularly important due to its unique duplex structure and excellent performance. Ultrasonic phased array testing is an advanced non-destructive testing technology that can implement on-site testing of the butt girth weld of the pipe and has good detection capabilities. In addition, radiographic testing and conventional ultrasonic testing are also commonly used detection methods, but radiographic testing has ionizing radiation, which is harmful to the personal safety of the inspectors, so special attention should be paid in practical applications.

In addition to the above inspection and testing requirements, in order to ensure the quality of 31803 duplex steel welded coils, manufacturers also need to establish a strict quality control system, including raw material incoming inspection, production process control, finished product inspection and other links. At the same time, regular quality management system audits and product certifications are required to ensure that products meet international standards and customer requirements.

In summary, the inspection and testing of ASTM A789/A790 31803 duplex steel welded coils needs to follow a series of specific standards and requirements to ensure their quality and performance. These standards and requirements not only cover all aspects of the production process, but also include various inspections and tests of finished products. Only in this way can we ensure that 31803 duplex steel welded coils can still show excellent corrosion resistance and mechanical properties in a variety of extreme environments, and make greater contributions to the development of modern industry.