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The cost advantage of high-strength duplex steel flanges is not purely reflected in the procurement unit price, but is realized through multi-dimensional performance optimization, life-cycle cost reduction and application scenario suitability, etc. The specific advantages are as follows:
1. Cost optimization of material consumption and structural design
The yield strength of high-strength duplex steels (such as super duplex steels S32750, S32760) is up to 450MPa or more, which is about twice as much as 304 stainless steel. The yield strength of high-strength duplex steels (e.g. Super Duplex S32750, S32760) can reach more than 450MPa, which is about twice that of 304 stainless steel. This characteristic makes it in the same pressure, temperature conditions, can be used thinner flange thickness or smaller nominal diameter, directly reduce the amount of material. For example:

In high-pressure pipeline systems, the use of high-strength duplex steel flanges can reduce the flange thickness by 30% to 50%, reducing material costs with the amount of year-on-year.
Lightweight structure can also reduce the cost of labor and machinery during transportation and installation, especially in offshore platforms, aerial work and other scenarios, the indirect cost savings brought about by improved installation efficiency are more significant. 2.
2. Reduced maintenance and replacement costs due to corrosion resistance
High-strength duplex steels exhibit excellent resistance to stress corrosion cracking (SCC) and pitting in chloride environments, seawater corrosion, and acidic media due to the alloying ratios of high chromium (25%+), high molybdenum (3%~5%) and nitrogen. Advantages over ordinary stainless steel or low grade duplex steel:

Reduction of anticorrosion coating or cathodic protection input: in marine engineering, ordinary carbon steel flanges need additional spraying of anticorrosion layer (costing 10%~20% of the total flange price), while high-strength duplex steel can be used directly exposed, eliminating the cost of coating.
Extend the replacement cycle: In chemical refining plants, ordinary flanges may need to be replaced in 3~5 years due to corrosion, while the service life of high-strength duplex steel flanges can be more than 15 years, and the downtime loss, labor cost and material waste cost brought by the reduced replacement frequency can be reduced by more than 50%.
3. Reliability enhancement reduces the cost of accident risk
The high strength and high toughness of high-strength duplex steel (impact work ≥ 50J) make it less likely to deform or crack under high pressure, vibration or alternating load conditions, thus avoiding safety accidents or media loss caused by leakage. For example:

In natural gas transmission pipelines, high-strength duplex steel flanges can withstand more than 10MPa pressure, if the use of low-strength materials may need to increase the redundancy of the design (such as flange thickening, increase the support), but to push up the cost; and high-strength materials by virtue of the reliability of the reduction of maintenance after an accident, compensation, and environmental fines and other hidden costs.
4. Comprehensive Advantages of Life Cycle Costs (LCC)
Although the procurement cost of high-strength dual-phase steel flanges is 30%~80% higher than that of low-grade materials, the cost advantages are reflected in the whole life cycle:

Energy consumption and process cost sharing: Although the smelting process of high-grade materials is complicated (e.g. vacuum melting), due to its excellent performance, it can “take one for the team” in key equipment and reduce the number of flanges used in the system. For example, in large petrochemical plants, the use of high-strength duplex steel flanges can reduce the number of connection points by 20%, and the cost of supporting bolts, gaskets and other accessories falls simultaneously.
Residual value and recycling value: High-strength duplex steel contains a high proportion of alloying elements, so it has a higher recycling value after scrapping. Compared with carbon steel or low-alloyed materials, the recycling premium can reach 15%-20% of the original value of the material, which further dilutes the total cost of ownership.
5. Unsubstitutable Cost Advantages in Special Scenarios
In extreme environments such as deep-sea oil and gas, nuclear power, aerospace, etc., high-strength duplex steel is one of the few materials that can meet the performance requirements, and at this time, its cost advantage is not to be compared with the lower-priced materials, but rather to avoid the overthrow of the design program or the postponement of the project due to the lack of material performance. Example:

Deep-sea pipeline flange if the use of low-strength materials, the need to increase the heavy pressure-resistant shell, the overall cost of the equipment may be higher than the direct use of high-strength dual-phase steel 2 to 3 times; and high-strength materials with high-pressure resistance, seawater corrosion resistance, the only economically viable option.
Summary
The cost advantage of high-strength duplex steel flanges is essentially the embodiment of “performance for cost”: through the upgrading of material performance, full-cycle cost optimization can be achieved in terms of material usage, maintenance cycle, reliability and adaptability to special scenarios. For long-term operation of high-risk, highly corrosive conditions, the choice of high-strength materials may seem to increase the initial investment, but in fact, by reducing the probability of failure, extending the service life to achieve the minimization of total costs, which is also the industrial field “cost-effective priority over the unit price” of the typical decision-making logic.