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Eternal
1.4420 (EN X2CrNiMoN21-9-1) is a high-chromium, high-nitrogen, ultra-low-carbon austenitic stainless steel. Through a carefully balanced alloy mix—raising chromium (Cr) and nitrogen (N) and controlling the amount of nickel (Ni) and molybdenum (Mo)—it keeps or even improves corrosion resistance while clearly cutting costs and improving efficiency. It is an ideal upgraded replacement for 316L (1.4404).
Jiangyin Eternal Heavy Industry Co., Ltd. is a professional forging factory. It uses open-die forging to make 1.4420 stainless steel forgings, including shafts, discs, rings, cylinders, flanges, and valve bodies. These products are widely used in marine engineering, petrochemicals, LNG storage and transport, water treatment, and energy equipment.
Standard | Grade |
EN | 1.4420 / X2CrNiMoN21-9-1 |
AISI（similar） | 317LMN（similar） |
ASTM / UNS | UNS S31726（similar） |
commercial | Supra 316plus®（Outokumpu） |
日本 JIS | SUS 317LN（similar） |
Element | % | Action |
C | ≤ 0.03 | Ultra-low carbon design to ensure the corrosion resistance of the welded joints |
Cr | 19.5 – 21.5 | Provide basic corrosion resistance and form a protective film |
Ni | 8.5 – 9.5 | Stable austenitic structure |
Mo | 2.5 – 3.0 | Enhance the resistance to pitting corrosion and crevice corrosion |
N | 0.15 – 0.20 | Solid solution strengthening, enhancing strength and corrosion resistance |
Mn | ≤ 1.2 | — |
Si | ≤ 0.8 | — |
P | ≤ 0.03 | impurity control |
S | ≤ 0.02 | impurity control |
Key indicator - PREN value: The corrosion resistance equivalent value (PREN = Cr + 3.3Mo + 16N) of 1.4420 is approximately 26, which is significantly higher than that of 316L (about 24). It has stronger resistance to pitting corrosion and crevice corrosion in environments with chloride ions.
Item | Value |
yield strength Rp0.2 | ≥ 320 MPa |
tensile strength Rm | 630 – 850 MPa |
elongation A | ≥ 40% |
hardness | ≤ 240 HB |
elasticity modulus | 190 – 215 GPa |
The yield strength of 1.4420 is approximately 30% higher than that of 316L. This means that under the same design load, the wall thickness can be reduced and the weight of the component can be decreased, thereby further reducing the overall cost.
1.4420 is a high-alloy austenitic stainless steel. During the forging process, it is necessary to pay attention to its low thermal conductivity, high deformation resistance and tendency to oxidize. We adopt the following process parameters to ensure the quality of the forged piece:
technical parameter | range |
preheat temp | 650 – 760℃ |
heat temp | 1120 – 1260℃ |
initial forging temperature | ≥ 1100℃ |
final forging temperature | ≥ 900℃ |
cooling | air |
The standard heat treatment method for the 1.4420 forging is solution treatment.
technical parameter | range |
solution temperature | 1030 – 1110℃ |
holding time | 1 h / 25 mm（no less 1 h） |
cooling | water or air |
hardness | ≤ 240 HB |
The purpose of solution treatment is to allow carbides and alloying elements to fully dissolve in the austenite, and after rapid cooling, to obtain a uniform and single austenite structure, thereby ensuring the best corrosion resistance and mechanical properties.
LNG Storage and Transport Equipment
1.4420 works very well in LNG storage tanks and transport containers. At very low temperatures down to -196°C, its strength and toughness do not drop; they even get better. It is an ideal material for LNG cargo tanks, transport tank containers, and other cryogenic equipment. Compared with the traditional 316L option, 1.4420 allows thinner walls. This directly makes LNG transport containers lighter, saves energy, and cuts costs.
Marine Engineering and Seawater Desalination
In marine engineering, 1.4420 forgings are used to make subsea pipeline connectors, pressure parts for seawater desalination equipment, marine fittings, and more. One customer used 60 mm diameter 1.4420 round steel to make subsea pipeline connectors. They first used 316L, and pitting appeared after only two years. After switching to 1.4420, it was used for four years; when checked, there was still only a uniform oxide film. The corrosion resistance advantage is very clear.
Chemical Pressure Vessels and Heat Exchangers
1.4420 forgings are widely used in chemical storage tanks, heat exchanger tube sheets, reactor flanges, piping systems, and other pressure parts. Its high PREN value and excellent resistance to chloride corrosion let it handle tough conditions often seen in chemical production, such as chloride ions and acid media.
Water Treatment and Building Structures
In water treatment systems and buildings, 1.4420 is used to make wastewater treatment equipment parts, drinking water pipe fittings, indoor and outdoor building curtain wall connectors, and more. It combines corrosion resistance and structural strength.
Material Guarantee: We provide an EN 10204 3.1 material certificate for every batch. Both chemical composition and mechanical properties are verified.
Mature Forging Process: The heating and deformation processes are optimized for the high-alloy characteristics of 1.4420. This ensures a dense structure and proper flow lines.
Non-Destructive Testing: 100% ultrasonic testing (UT) is done before the forgings leave the factory. It is strictly carried out according to JB/T 8467 or customer-specified standards. This eliminates internal inclusions, cracks, and other defects.
Solution Treatment Included: We have our own heat treatment furnace. After solution treatment, water cooling is used. Hardness is ≤240 HB, which meets the needs of later machining.
Flexible Specifications: We can produce shaft, disc, ring, and cylinder forgings with diameters from 100 mm to 3000 mm. We can customize according to your drawings.
What is the difference between 1.4420 and 316L? Which one is more suitable?
1.4420 has a higher chromium content (about 21%) than 316L (about 17%). It also has 0.15–0.20% nitrogen added. Its PREN value is higher (26 vs 24), so it has better resistance to pitting corrosion and crevice corrosion. At the same time, 1.4420 uses less nickel and molybdenum, so the alloy cost is more competitive. If your application has a chloride corrosion risk (such as seawater or chemical media) or needs higher strength, 1.4420 is an ideal upgrade from 316L.
Is 1.4420 ferritic or austenitic stainless steel?
1.4420 is austenitic stainless steel. Its correct EN grade is X2CrNiMoN21-9-1, and it belongs to the high-chromium austenitic stainless steel family. Some information on the market wrongly labels it as "ferritic" or "duplex steel." Please check carefully.
What product forms can 1.4420 forgings be made into?
We can produce various free forgings, including shafts, discs, rings, cylinders, blocks, flanges, valve bodies, etc. Sizes cover diameter 100 mm–1500 mm, and single piece weight can reach up to 10 tons. We support customization according to drawings.
What is the delivery condition of 1.4420 forgings?
The standard delivery condition is solution treatment + water cooling, with hardness ≤240 HB. This makes later machining easier for customers. Other heat treatment conditions can be customized upon discussion.
Can 1.4420 replace 316L?
Yes. 1.4420 is better than 316L in both corrosion resistance and strength, and its alloy cost is lower. In marine engineering, chemical, LNG, and other fields, there are many successful cases of replacing 316L with 1.4420.
Do the forgings come with material certificates and test reports?
Yes. Each batch of forgings is supplied with an EN 10204 3.1 material certificate, including chemical composition analysis and mechanical property test results. We can also provide ultrasonic testing reports, intergranular corrosion test reports, etc., according to customer requirements.
