The grade 254 SMO stainless steel is an austenitic stainless steel that is of the highest quality. It has twice the strength of the stainless steel 300 series as well as a combination of impact toughness, resistance to chloride stress corrosion, cracking, pitting, and crevice corrosion. Among the many advantages of Grade SMO 254, buttweld fittings are that they are a cost-effective alternative to the high nickel and titanium alloys that are commonly used in certain applications. They are also known to have outstanding workability characteristics and are less expensive than those of high nickel and titanium alloys. The pipes and tubes in this line are available in a wide variety of sizes, standards, thicknesses, and requirements, so as to accommodate a wide range of applications in seawater and chloride mediums. This grade has a remarkable antifouling quality, particularly in seawater, which is especially noticeable. It is incredibly resistant to pitting and cracking, as well as to ordinary corrosion, and it also bears stress corrosion cracking when impacted. The SMO grade has a lot of strength. Due to the weldability of SMO pipes and tubes, it is possible to weld them directly with any sort of filler material and even have them regulated at low temperatures, making them an ideal option for welding and shaping, and making them into any complex shape.
Seawater and other aggressive chloride-bearing media are suitable for the use of stainless steel SMO 254. As a result of electro-slag remelting, the alloy is a cleaner and more segregation-free material. However, the grade of the steel is defined by its degree of resistance to corrosion.
- Despite the fact that it is highly resistant to corrosion cracking from stress, it is easy to maintain.
- The alloy has excellent weldability compared to the other alloys.
Standards of SMO 254
- S31254 is the UNS number
- 1.4547 is the EN number
- 2378 SS
Supply Forms of Steel: Depending on the parameters that you specify, steel can be supplied in different forms that are analyzable as follows:
1) Sizes and tolerances:
This SMO 254 is available in a wide range of sizes, such as round-cornered squares, round billets, etc. as well as in several different shapes.
2) Surface conditions of steel:
- Square billets:
SMO 254 billets must be buried, spot buried, or fully buried on a surface that is either underground, spot buried, or fully buried.
- Round billets:
In order to make this type of SMO 254, it must have a peel-turned or black finish.
Approvals of SMO 254:
- A seamless pipe made from SMO 254 is available in the form of seamless pipe and is approved by the American Society of Mechanical Engineers for use in accordance with the rules and regulations stipulated in the ASME boiler and pressure vessel code section VIII for boilers and pressure vessels.
- In addition, SMO 254 is not approved by UNS S31254 when it comes to seamless tubes. However, it is allowed to go through the design values when it comes to seamless pipes.
- Moreover, it is approved according to the NACE MR 0175 standard which confirms its suitability.
SMO 254 Characteristics
There are products that perform well in halide solutions with chloride and bromide ions present. This grade demonstrates the impact of local corrosion resulting from pitting, crevices, tension, and other local influences. In SMO 254, the carbon content is low, which reduces the likelihood of carbide precipitation in welding activities because it has a low carbon content. Because of the reduced carbide content, the welding process is less likely to produce carbide precipitation.
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Machinability
Stainless steel grade 254 SMOTM is quite hard to mill because of its exceptionally rapid work hardening rate and lack of sulfur content; however, sharp tools, powerful machine machines, positive feeds, generous lubrication, and slow speeds tend to provide decent machining results.
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Welding
It is necessary to utilize filler materials when welding stainless steel 254 SMO material due to its inferior properties for tensile strength. ERNiCrMo-3, alloy 625 is approved as filler metals in AWS A5.14, while the electrodes for welding must meet AWS A5.11 ENiCrMo-12 requirements.
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Annealing
An annealing temperature of 1149-1204°C (2100-2200°F) is recommended for this material before quenching with water.
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Working in Extreme Conditions
It can be forged, upset, and used for a variety of operations between 982°C and 1149°C (1800 to 2100°F). In order to achieve maximum corrosion resistance, it is recommended to undergo post-process annealing. Temperatures above this range will result in scaling and reduce the material's workability.
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Working in the Cold,
As a result, the material, once cold worked, will have higher strength and toughness as a result of the higher work hardening rate.
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Hardening
The hardenability of the stainless steel grade 254 SMO is determined by cold reduction, not by heat treatment.
Applications of SMO 254
The following applications use stainless steel grade 254 SMO
- Handling saltwater in a marine environment
- Columns of tall oil distillation equipment
- Scrubbers for the desulfurization of flue gases
- The components that are used in the production of petroleum
- Equipment used in the food processing industry
- Various types of process equipment are used in the chemical industry
- Equipment used in pulp and paper industries for bleaching
- Flue-gas cleaning
- Desalination
- Heat exchangers
