Stainless Steel, Duplex
S32101 Stainless Steel (1.4162)
A low-alloyed, general purpose lean duplex stainless steel.
S32101 is a lean duplex stainless steel (ferritic–austenitic microstructure) with the trade name LDX 2101® in many mills. It combines about 21–22% chromium with high manganese and a low nickel content, plus nitrogen and small additions of molybdenum and copper. This balanced composition provides high mechanical strength, good resistance to localized corrosion, and excellent stress-corrosion cracking resistance in chloride-containing environments.
Compared with conventional 304L stainless steel, S32101 offers roughly twice the yield strength and generally better pitting and crevice-corrosion resistance, approaching or matching 316L in many service conditions, while keeping alloy cost lower thanks to its reduced nickel content.
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S32101 Stainless Steel Related Specifications
| System / Standard | Country / Region | Grade / Designation |
| UNS | International | S32101 |
| EN / W.Nr. | Europe | 1.4162 |
| EN Name (EN 10088) | Europe | X2CrMnNiN21-5-1 |
| ASTM A240 | USA | S32101 (plate, sheet, strip) |
| ASTM A276 | USA | S32101 (bars, shapes) |
| ASTM A479 | USA | S32101 (bars, shapes) |
| ASTM A789 | USA | S32101 (tubing) |
| ASTM A790 | USA | S32101 (pipe) |
| GB / GB/T 20878 | China | S32101 |
| JIS (approx.) | Japan | SUS821L1 |
| Trade name | International | LDX 2101 |
| Trade name | International | Forta LDX 2101 |
| Producer grade | International | J2101 |
Properties
Chemical Composition
| Chemical Element | % Present |
| Carbon (C) | 0.00 - 0.04 |
| Chromium (Cr) | 21.00 - 22.00 |
| Nickel (Ni) | 1.35 - 1.70 |
| Manganese (Mn) | 4.00 - 6.00 |
| Molybdenum (Mo) | 1.00 - 0.80 |
| Sulphur (S) | 0.00 - 0.03 |
| Phosphorous (P) | 0.00 - 0.04 |
| Copper (Cu) | 0.10 - 0.80 |
| Nitrogen (N) | 0.20 - 0.25 |
| Iron (Fe) | Balance |
Mechanical Properties
| Mechanical Property | Value |
| Proof Stress | 450 Min MPa |
| Tensile Strength | 650 Min MPa |
| Elongation A50 mm | 30 Min % |
General Physical Properties
| Physical Property | Value |
| Density | 7.8 g/cm³ |
| Modulus of Elasticity | 200 GPa |
Applications of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / EN 1.4162) is a lean duplex stainless steel that combines high yield strength, good corrosion resistance (≈ 316L level in many media) and excellent resistance to chloride stress-corrosion cracking, with a more cost-stable, low-nickel composition.
1. Storage Tanks and Process Vessels
Storage tanks for water, process liquids and mild chemicals where 304L/316L strength is insufficient
Process vessels in food, beverage, pharmaceutical and biotech plants
Dimple-jacketed and agitated tanks where higher strength allows thinner walls and lighter constructions
2. Pulp, Paper and General Chemical Processing
Digesters, bleaching equipment and liquor handling systems in pulp and paper mills
Piping, vessels and heat exchangers for mildly to moderately aggressive process chemicals
Agitated process equipment where corrosion-fatigue resistance and strength are important
3. Desalination, Water and Wastewater Treatment
Desalination plant equipment, seawater tanks and brackish-water systems
Large potable and process-water storage tanks, distribution lines and fittings
Wastewater treatment basins, channels, gates and other water-control structures
4. Structural Components, Infrastructure and Fasteners
Structural members in bridges, walkways and architectural elements exposed to de-icing salts or marine atmospheres
Stainless reinforcing bars in concrete for coastal or chloride-contaminated environments
High-strength bolts, screws, shafts, flanges and fittings requiring both load capacity and corrosion resistance
5. Marine, Shipbuilding and Transport Equipment
Shipbuilding structures and deck hardware in splash and tidal zones
Cargo and chemical tanks, tank truck and railcar vessels where weight saving is beneficial
Ballast-water treatment units and exhaust-gas cleaning (scrubber) systems
6. Energy, Oil & Gas and Power Generation
Process piping, manifolds and equipment in oil & gas and petrochemical plants
Cooling-water systems, condensers and heat-exchanger components in power plants
General high-strength, corrosion-resistant mechanical parts in rotating and static equipment
Summary
S32101 (LDX 2101 / 1.4162) lean duplex stainless steel is widely used in tanks and vessels, pulp and paper and chemical plants, water and wastewater systems, structural and fastener applications, marine and transport equipment, and energy/oil & gas/power-generation components, wherever designers need higher strength and better SCC resistance than 304/316L, while maintaining corrosion resistance that is generally superior to 304L and competitive with 316L in many service environments.
Characteristics of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / EN 1.4162) is a lean duplex stainless steel that combines a duplex (austenite + ferrite) microstructure with high yield strength, good corrosion resistance and excellent resistance to chloride stress-corrosion cracking, at a lower alloy and nickel cost than 316L.
1. Lean Duplex Microstructure with Low-Nickel Design
Duplex microstructure of roughly 50% ferrite / 50% austenite gives a balance of strength and toughness.
“Lean” alloy design uses lower nickel and increased manganese and nitrogen to stabilise austenite and control cost.
Provides duplex-level performance (strength + SCC resistance) with more stable pricing than high-Ni duplex and austenitic grades.
2. High Yield Strength and Structural Efficiency
Yield strength is about twice that of 304L/316L, allowing:
Thinner walls
Lighter constructions
Smaller cross-sections for the same load
High strength and good fatigue performance make it well suited to tanks, structural members, pipework and mechanical components.
3. Corrosion Resistance Comparable to 316L in Many Media
General corrosion resistance is better than 304L and broadly comparable to 316L in many mildly to moderately aggressive environments.
Good resistance to pitting and crevice corrosion in chloride-bearing waters (seawater, brackish and process waters), provided design avoids severe crevices and deposits.
Suitable for many chemical, pulp & paper, water treatment and marine-atmospheric environments.
4. Excellent Resistance to Chloride Stress-Corrosion Cracking
Duplex structure gives very high resistance to chloride stress-corrosion cracking (SCC) compared with austenitic grades.
Much lower SCC susceptibility than 304L/316L under combined chloride + tensile stress + elevated temperature conditions.
Particularly advantageous for desalination, cooling water, seawater-contact, structural and high-load applications where SCC is a typical failure mode for 300-series stainless steels.
5. Good Weldability and Fabrication Behaviour
Weldable using standard duplex welding practices with nitrogen-balanced duplex or over-alloyed austenitic fillers.
Heat input and interpass temperature must be controlled to maintain the correct ferrite–austenite balance and avoid loss of toughness or corrosion resistance.
Formability is generally good, though somewhat lower ductility than 304/316 means tighter bends and heavy forming require attention to tooling, radii and, if necessary, intermediate heat treatment.
6. Mechanical and Physical Property Balance
Combines high strength, good toughness and good fatigue resistance, including in corrosive media.
Toughness is lower than austenitic grades but adequate for most engineering uses when correctly fabricated and welded.
Shows lower thermal expansion and higher stiffness (elastic modulus) than 304/316, improving dimensional stability in structural and temperature-cycling applications.
Duplex structure gives a magnetic response, unlike non-magnetic austenitic grades in the annealed condition.
Summary
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel with a duplex microstructure, high yield strength, corrosion resistance generally superior to 304L and comparable to 316L in many environments, excellent resistance to chloride stress-corrosion cracking, good weldability and a favourable strength-to-cost ratio, making it an attractive choice for tanks, structural components, piping and marine/chemical service where both mechanical performance and corrosion resistance are critical.
Additional Information
Weldability
Weldability of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel with generally good weldability, but—like all duplex grades—it requires controlled welding procedures to preserve the correct ferrite–austenite balance and maintain toughness and corrosion resistance.
1. General Weldability Characteristics
Weldable with conventional stainless-steel welding processes when heat input and interpass temperature are properly controlled.
Duplex microstructure means welding must avoid:
Excessive ferrite (too low heat input / too fast cooling)
Excessive austenite / intermetallics (too high heat input / high interpass temperature)
Compared with higher-alloy duplex grades, lean duplex S32101 is more forgiving and easier to weld, but still less tolerant than austenitic 304/316 to poor procedures.
2. Suitable Welding Processes
Commonly used processes:
GTAW (TIG) – for root passes and thin sections, with excellent control of heat input.
GMAW (MIG/MAG) – for production welding of plate, tube, tanks and structures.
SMAW (MMA) – for site work and repairs with appropriate duplex electrodes.
FCAW – for higher deposition rates in fabrication shops using duplex flux-cored wires.
Autogenous (no-filler) welding is not recommended except for very thin gauges, because filler composition is important to restore the correct phase balance.
3. Filler Metal Selection
Filler metals are typically duplex or slightly over-alloyed austenitic grades, chosen to:
Achieve the correct ferrite–austenite balance in the weld metal.
Provide pitting and crevice corrosion resistance at least equal to the base metal.
For most applications:
Use duplex filler designed for lean duplex or standard duplex steels.
Over-alloyed austenitic fillers may be used in some cases to maximise weld toughness, especially in highly restrained joints, but should still provide adequate corrosion resistance.
Matching the filler to both corrosion requirements and mechanical property targets is essential in seawater, desalination, chemical and structural service.
4. Heat Input, Interpass Temperature and Cooling
Controlled heat input is critical:
Too low → excess ferrite, reduced toughness and corrosion resistance.
Too high → risk of excessive austenite and/or intermetallic phases, reducing impact toughness and corrosion performance.
Typical practice:
Keep heat input in a moderate band (not extremely low or high; follow filler/manufacturer guidance).
Limit interpass temperature (often in the ~100–150°C range) to avoid over-tempering and intermetallic formation.
Allow the weld to cool in still air; water quenching is not used.
Good control helps ensure weld metal and HAZ retain a balanced duplex structure with mechanical and corrosion properties close to the parent plate.
5. Weld Microstructure, Properties and Corrosion Behaviour
Properly welded S32101 joints show:
A duplex weld metal with roughly 30–70% ferrite, depending on procedure and thickness.
Good toughness and fatigue resistance for structural and pressure applications.
Corrosion resistance comparable to the parent metal in many service environments.
Poor welding practice can result in:
Ferrite-rich welds with lower toughness and reduced corrosion resistance.
Formation of intermetallic phases in overheated HAZ or weld metal, causing impact-toughness loss and pitting susceptibility.
Post-weld pickling and passivation (or mechanical cleaning plus passivation) are important to restore a clean, chromium-rich surface and remove heat tint, slag and contaminants.
6. Practical Fabrication Guidelines
Design joints to:
Avoid excessive restraint and high residual stresses (which can promote cracking and SCC).
Provide good access for both welding and cleaning.
Use:
Back purging with inert gas on root passes for pipe and tank welding to protect the weld root from oxidation.
Qualified welding procedures (WPS / PQR) specifically developed for duplex steels.
Duplex-aware NDE techniques where critical (e.g. ferrite measurement in weld metal / HAZ, as required by some codes).
For critical service (desalination, structural bridges, offshore, chemical tanks), follow material supplier and code guidance on allowable heat input, ferrite range and PWHT (typically none for S32101, unless specified for stress reasons).
Summary
S32101 (LDX 2101 / 1.4162) stainless steel has good weldability for a duplex grade, provided duplex-appropriate procedures are used: moderate heat input, controlled interpass temperature, suitable duplex or over-alloyed austenitic fillers, proper cleaning and joint design all ensure a balanced duplex weld microstructure with mechanical and corrosion properties matching the lean duplex base metal in demanding structural, tank, piping and marine applications.
Fabrication
Fabrication of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel. Fabrication is broadly similar to other duplex grades: it machines and welds well with the right procedures, but its higher strength and duplex (ferrite + austenite) structure mean you must pay attention to forming loads, heat input and post-weld cleaning.
1. General Fabrication Approach
Normally supplied solution-annealed and pickled (plate, sheet, coil, tube).
Most forming, cutting, machining and welding are done in this condition.
Because yield strength is roughly twice that of 304/316, designs can use thinner sections – but forming and cutting forces are higher.
Fabrication planning should always consider:
Maintaining the duplex phase balance
Avoiding excessive cold work without subsequent heat treatment
Ensuring adequate machining allowances for scale and distortion
2. Forming and Cold Working
Cold formability is good but lower ductility than 304/316 due to higher strength.
Recommended practice:
Use larger bend radii than you would for 304/316.
Apply gradual forming with good lubrication to reduce galling.
For severe forming (deep drawing, tight bends on thicker plate), consider stepwise forming with intermediate annealing (supplier guidance) if properties are critical.
Cold work increases strength and hardness and introduces residual stresses; for demanding corrosion or fatigue service, avoid very heavy cold deformation unless followed by appropriate heat treatment.
3. Hot Working and Heat Treatment in the Route
Hot working (forging, hot forming) is carried out in a similar range to other duplex steels.
Key points:
Heat uniformly through section before deformation.
Use substantial reductions, not light tapping, to refine grains.
After heavy hot work, perform a solution anneal + rapid cooling (typically water quench or fast air, per supplier spec) to restore a balanced duplex structure and full corrosion resistance.
For most plate and light-gauge products, hot working is done at the mill; fabricators mainly deal with cold forming + welding.
4. Machining
Machinability is similar to other duplex steels and generally more demanding than 304/316 because of higher strength.
Good practice:
Use rigid setups and sharp carbide tooling.
Run moderate cutting speeds with adequate feed to avoid rubbing and excessive work hardening.
Apply plenty of coolant for heat removal and chip control.
Plan the route as:
Rough machining in the solution-annealed condition → welding/forming → final light finish machining or grinding to restore tolerances and surface finish after any distortion.
5. Welding as Part of Fabrication
S32101 has good weldability for a duplex grade, but duplex rules apply:
Use duplex or slightly over-alloyed austenitic fillers recommended for lean duplex.
Keep heat input and interpass temperature within the ranges specified for duplex steels to maintain a healthy ferrite–austenite balance.
Use back purging and good shielding on pipe/tank roots to avoid oxidation.
Normally no post-weld heat treatment is required; the crucial step is:
Thorough post-weld cleaning (grinding/pickling/passivation) to remove heat tint and contamination and recover corrosion resistance.
6. Surface Finishing, Cleaning and Dimensional Control
For best corrosion performance:
Remove scale, heat tint, slag and spatter from welds and HAZ.
Use suitable pickling or mechanical cleaning plus passivation to restore a clean, chromium-rich passive film.
Prefer smooth, ground or brushed finishes in aggressive or chloride environments.
Dimensional considerations:
Higher strength means stronger forming and residual stresses; control fixturing and sequence in welding and forming to minimise distortion.
Duplex steels have lower thermal expansion than austenitics, which helps with dimensional stability in service, but parts still need sensible welding sequences and clamps during fabrication.
Summary
S32101 (LDX 2101 / 1.4162) is straightforward to fabricate when treated as a high-strength duplex stainless steel: do most forming and machining in the solution-annealed state, use duplex-appropriate welding procedures with controlled heat input and correct filler, and always finish with proper cleaning, pickling/passivation and light final machining or grinding to deliver the required duplex microstructure, corrosion resistance, dimensional accuracy and surface quality.
Hot Working
Hot Working of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel that can be hot worked using similar practices to other duplex grades. Correct temperature control, reductions and cooling are important to maintain a balanced ferrite–austenite structure and good mechanical and corrosion properties.
1. Recommended Hot Working Temperature Range
Typical hot-working / forging range is about 950–1,150°C.
Start deformation toward the upper end of the range for best plasticity.
Finish hot working above roughly 900°C to avoid cracking as ductility drops at lower temperatures.
Exact temperatures and soak times should follow the mill’s data sheet for the specific product.
2. Heating and Forging Practice
Heat material slowly and uniformly through the section before heavy deformation.
Use firm, substantial reductions per pass (not light tapping) to promote good grain refinement.
For large forgings or complex shapes, reheat as soon as temperature approaches the lower working limit.
Avoid overheating or long soaking at peak temperature to limit grain growth and excessive scaling.
3. Cooling After Hot Working
After hot forming or forging, cool components in still air or controlled conditions.
For heavily hot-worked pieces, a subsequent solution anneal + rapid cooling is recommended to:
Restore a proper duplex (ferrite–austenite) balance
Maximise toughness and corrosion resistance
Avoid very slow cooling through the 475–1,000°C range, which may allow formation of undesirable phases in duplex steels.
4. Surface Scale, Machining Allowance and Cleaning
At forging temperatures S32101 will form oxide scale and some surface roughening.
Allow a suitable machining/grinding allowance to remove scale and any decarburised or damaged surface layer.
After hot working and any solution anneal, use pickling and/or mechanical cleaning plus passivation to achieve a clean, metallic surface with full corrosion resistance.
5. Effect on Microstructure and Properties
Correctly performed hot working in the right temperature range produces a fine, balanced duplex microstructure.
A refined structure improves:
Toughness and ductility
Fatigue performance
Uniformity of corrosion behaviour through the section
Poor control (overheating, insufficient reduction, too slow cooling) can lead to coarse grains or unwanted phases, reducing impact toughness and pitting resistance.
6. Design, Distortion and Cracking Control
Preforms and forgings should be designed with smooth transitions and generous radii to reduce stress concentrations.
Avoid sharp corners, abrupt thickness changes and heavy local reductions that promote cracking during forging or cooling.
For long shafts, rings or complex shapes, use proper support and handling during hot working and cooling to minimise bending and distortion.
Inspect forgings for laps, folds and surface cracks before committing to final heat treatment and machining.
Summary
Hot working of S32101 (LDX 2101 / 1.4162) is best carried out in the 950–1,150°C range with uniform heating, substantial reductions and controlled air cooling, followed where necessary by solution annealing and proper cleaning; this approach preserves a fine, balanced duplex microstructure and ensures the high strength, toughness and corrosion resistance required for demanding structural, tank and piping applications.
Heat Resistance
Heat Resistance of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel designed mainly for ambient to moderately elevated temperature service, especially in chloride-containing environments. It has good strength retention and SCC resistance at moderate temperatures, but it is not a high-temperature or creep-resistant alloy.
1. Recommended Service Temperature Range
Best suited for continuous service from ambient up to roughly 200–250°C.
Within this range, it maintains:
High yield strength compared with 304/316
Good toughness and corrosion resistance
Long-term use at significantly higher temperatures is generally not recommended, because duplex steels can:
Form embrittling phases (e.g. sigma, 475°C embrittlement) with prolonged exposure
Lose toughness and corrosion resistance if held too long at intermediate/high temperatures
2. Strength and Toughness at Elevated Temperatures
As temperature rises, S32101 behaves like other steels:
Yield and tensile strength decrease with increasing temperature
Fatigue strength is reduced under cyclic loading
Even so, within its recommended range it still offers:
Higher strength than 304L/316L at the same temperature
Good structural efficiency for tanks, piping and structural members
Toughness remains adequate in the intended range, but duplex grades are not intended for very high-temperature, creep-limited service.
3. Chloride Environments and Elevated Temperature Wet Service
One key advantage of S32101 is its excellent resistance to chloride stress-corrosion cracking (SCC) compared with 304/316:
In warm chlorinated waters, desalination, cooling water and seawater splash zones, it is much more resistant to SCC.
However, like all stainless steels:
High temperature + high chloride + high tensile stress can still create SCC risk if limits are exceeded.
Design should keep service temperature and stress levels within recommended ranges, especially for critical wet-service components.
4. Oxidation and Surface Behaviour at Higher Temperatures
Chromium content gives good oxidation resistance for moderate-temperature service in air or flue-like atmospheres.
For temperatures much above the normal design range, dedicated heat-resistant austenitic or nickel alloys are preferable.
Smooth, clean surfaces (no heavy scale, heat tint or contamination) help:
Maintain oxidation resistance
Preserve fatigue and corrosion performance under temperature cycling
5. Design and Heat-Exposure Considerations
Avoid prolonged exposure in temperature bands where duplex steels can form embrittling intermetallic phases (typically mid-to-high temperature regions).
For components that may occasionally see higher excursions (e.g. during upset or cleaning cycles), design should:
Limit exposure time
Ensure proper cooling back into the safe operating range
S32101 is best treated as a high-strength, corrosion-resistant structural stainless, not as a primary material for long-term high-temperature / creep applications.
Summary
S32101 (LDX 2101 / 1.4162) offers good heat resistance for structural and process equipment operating at moderate temperatures (roughly up to 200–250°C), retaining higher strength than 304/316 and excellent resistance to chloride SCC; however, it is not designed for long-term high-temperature or creep-critical service, so for sustained exposure at significantly higher temperatures, more highly alloyed heat-resistant stainless steels or nickel alloys should be selected.
Machinability
Machinability of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel with higher strength and stiffness than 304/316, and machinability broadly similar to other duplex grades: workable, but more demanding than austenitic stainless steels and far from a free-cutting steel.
1. General Machining Behaviour
Higher yield strength means higher cutting forces than 304/316.
Work hardening is less extreme than austenitic grades, but still present if feeds are too light or tools are dull.
Surface finish and tool life are very sensitive to:
Tool sharpness
Machine rigidity
Correct cutting data (speed, feed, depth of cut)
2. Preferred Condition for Machining
Best machinability is in the solution-annealed condition as delivered from the mill.
Avoid heavy cold work (severe forming, straightening) immediately before finish machining, as it:
Raises surface hardness
Increases tool wear
Makes dimensional control harder
For tight-tolerance parts, a good route is:
Rough machining → welding/forming (if needed) → straightening → finish machining / grinding.
3. Tooling and Cutting Parameters
Carbide tooling is strongly recommended for turning, milling and drilling.
Use:
Inserts and grades designed for stainless / duplex steels
Positive rake geometries to reduce cutting forces and heat
Rigid toolholders and solid fixturing to minimise chatter
Cutting data guidelines (conceptually):
Moderate cutting speeds, lower than for 304/316 at similar operations
Adequate feed and depth of cut to cut below any work-hardened skin
Avoid very light “polishing” cuts that only rub and harden the surface
4. Coolant Use and Chip Control
Duplex steels generate significant heat → coolant is essential:
Use plenty of cutting fluid / emulsion at the cutting zone
For deep holes and pockets, ensure good chip evacuation
S32101 tends to form tough, continuous chips:
Use inserts with effective chip breakers
Optimise feed + depth of cut to encourage chip breaking
Good chip control improves tool life, surface finish and process reliability (especially on CNC / automatic machines)
5. Drilling, Tapping and Threading
Drilling
Use carbide or cobalt HSS drills with robust web and good point geometry
Apply steady feed and avoid dwelling at the bottom of the hole
For deep holes, use peck drilling to clear chips and maintain cooling
Tapping / Threading
Use high-quality, strong taps with abundant lubrication
Keep speeds modest to control torque and avoid galling
For critical or large threads, thread milling is often preferable:
Lower risk of tool breakage
Better control of thread fit and minor-diameter size
6. Surface Finish, Distortion and Dimensional Control
With proper parameters, S32101 can achieve very good surface finishes after turning, milling and grinding.
For best dimensional control:
Use balanced machining (remove similar amounts of material from both sides of plates/rings where possible)
Avoid excessive local heating during heavy cuts or grinding to prevent:
Localised tempering
Residual tensile stresses
Minor distortion on thin or slender parts
Duplex steels have higher stiffness and lower thermal expansion than austenitics, which helps dimensional stability in service, but fabrication stresses and clamping must still be managed carefully.
Summary
S32101 (LDX 2101 / 1.4162) has moderate machinability for a high-strength duplex stainless steel: it machines cleanly when you use rigid setups, suitable duplex/stainless carbide tooling, conservative cutting speeds with adequate feed, generous coolant and effective chip breaking, combined with sensible process planning (roughing in the solution-annealed condition and finishing with light cuts) to achieve accurate dimensions, good tool life and high-quality surfaces on structural, tank, piping and mechanical components.
Corrosion Resistance
Corrosion Resistance of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel with corrosion resistance better than 304L and broadly comparable to 316L in many environments, plus much higher resistance to chloride stress-corrosion cracking (SCC) thanks to its duplex (austenite + ferrite) structure.
1. General Corrosion Behaviour
Good overall resistance to uniform corrosion in many industrial, marine-atmospheric and process environments.
Performs clearly better than 304L and typically close to 316L in many mildly to moderately aggressive chloride-containing waters.
The duplex structure and alloying (high Cr, N, lean Ni) give a robust passive film with good resistance to corrosion fatigue in agitated service.
2. Atmospheric and Aqueous Environments
Very good performance in rural, urban and marine atmospheres, with low risk of rust staining when surfaces are kept clean.
Suitable for fresh water, cooling water, process water and many natural waters where chlorides are low to moderate.
Widely used in tanks, piping, structural work and water-treatment equipment exposed to condensation, splash, spray and intermittent wetting/drying.
3. Pitting and Crevice Corrosion in Chloride Media
Improved pitting and crevice corrosion resistance compared with 304L due to higher chromium and nitrogen.
In many natural and process waters, resistance is similar to or slightly better than 316L, provided temperatures and chloride levels are not extreme.
As with all stainless steels, tight crevices, deposits and stagnant zones can become initiation sites; good design (smooth transitions, drainability, easy cleaning) is essential.
For very hot or highly concentrated chlorides (e.g. strong brines, evaporators at high temperature), more highly alloyed duplex or super-austenitic grades may be required.
4. Chloride Stress-Corrosion Cracking (SCC) Resistance
One of S32101’s key advantages is its excellent resistance to chloride SCC compared with austenitic grades:
Duplex microstructure makes it far less susceptible than 304/316 in warm, stressed, chloride-bearing service.
This is especially valuable in:
Desalination and cooling-water systems
Seawater-contact structures and piping
Bridge and infrastructure components exposed to de-icing salts
SCC risk is not zero, but the safe operating “window” (temperature × chloride × stress) is much wider than for 300-series stainless steels.
5. Intergranular Corrosion and Welded Joints
S32101 is designed to have good resistance to intergranular corrosion when correctly fabricated and welded.
With proper welding procedures (controlled heat input, suitable duplex or over-alloyed austenitic fillers, correct ferrite–austenite balance), weld metal and HAZ retain:
Good toughness
Corrosion behaviour close to the base metal
Excessive heat input or poor welding practice can promote formation of intermetallic phases or unbalanced microstructures, which reduce both toughness and corrosion resistance—so duplex-specific WPS/PQR control is important.
6. Influence of Surface Finish, Cleaning and Design
As with all stainless steels, surface condition strongly affects corrosion performance:
Smooth, ground or brushed finishes resist pitting and fouling better than rough, damaged or heavily heat-tinted surfaces.
Welds should be properly cleaned, pickled and/or passivated to remove oxides, slag and iron contamination.
Good design practice further improves corrosion resistance:
Avoid stagnant pockets, tight crevices and lap joints.
Provide drainage and access for inspection and cleaning.
Use compatible fasteners and avoid galvanic couples that could drive local attack in wet service.
Summary
S32101 (LDX 2101 / 1.4162) offers corrosion resistance superior to 304L and broadly comparable to 316L in many natural and process waters, combined with outstanding resistance to chloride stress-corrosion cracking and good pitting/crevice resistance for lean duplex level; when welded and finished correctly and used within its intended temperature and chloride ranges, it provides a very robust, cost-effective corrosion-resistant solution for tanks, piping, structural and marine-related applications.
Heat Treatment
Heat Treatment of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel. Like other duplex grades, it cannot be hardened by quenching in the way martensitic steels can; heat treatment is mainly used to obtain the correct duplex microstructure, restore toughness and corrosion resistance after forming or hot working, and control residual stress.
1. General Heat-Treatment Behaviour
Microstructure is roughly 50% ferrite / 50% austenite in the solution-annealed condition.
Strength comes from composition + duplex structure + any cold work, not from martensitic hardening.
Main treatments in practice are:
Solution annealing after hot working or heavy cold work
Very limited stress relief, only when absolutely necessary
Prolonged exposure in intermediate temperature ranges can form embrittling intermetallic phases, so duplex steels are not heat-treated like ordinary low-alloy or martensitic steels.
2. Solution Annealing (Softening / Resetting the Structure)
Purpose:
Restore a balanced duplex microstructure after hot working or heavy forming
Dissolve unwanted precipitates and recover toughness and corrosion resistance
Typical practice (exact range depends on mill spec):
Heat into a high-temperature solution-annealing range (around ≈ 1020–1100°C).
Soak long enough for full through-heating of the section.
Rapid cooling, usually water quench (or very fast air for thin sections), to freeze in the desired ferrite–austenite balance and avoid intermetallic formation.
After proper solution annealing and rapid cooling, S32101 has:
High yield strength for a stainless steel
Good impact toughness
Maximum available resistance to pitting, crevice and stress-corrosion cracking for this grade.
3. Stress Relief and Post-Fabrication Heat Treatment
Duplex steels in general, including S32101, do not usually require stress relief after welding or forming if good procedures are used.
Low-temperature “tempering-type” treatments used for carbon steels are not appropriate; holding duplex steels too long in mid-temperature ranges can:
Promote 475°C embrittlement
Encourage formation of intermetallic phases
Reduce toughness and corrosion resistance
If a code or design absolutely requires some stress relief, it must:
Be at relatively low temperature and short time, and
Follow the steelmaker’s or code guidance specifically for duplex grades
For most tanks, piping and structures in S32101, the preferred route is:
Fabricate (form + weld) in the solution-annealed condition,
Use proper welding parameters and fillers,
Then rely on careful cleaning, pickling and passivation, rather than PWHT, to achieve performance.
4. Effect of Heat Treatment on Microstructure and Properties
Correct solution annealing + rapid cooling gives:
A fine, balanced duplex structure
High yield strength and good toughness
Consistent corrosion behaviour through the section
Overheating, long soaking, or slow cooling in the intermediate range can:
Produce coarse grains
Allow sigma or other intermetallic phases to form
Lower impact toughness and make the steel more sensitive to pitting and SCC
S32101 does not gain extra strength from additional quenching steps; multiple uncontrolled heat cycles can actually damage properties instead of improving them.
5. Practical Heat-Treatment Guidelines for Fabricators
Treat S32101 as a duplex stainless, not as carbon steel or martensitic stainless:
No quench-hardening cycles
Avoid long holds in the 300–1000°C region unless following a qualified duplex procedure
Typical fabrication route:
Mill supply in solution-annealed condition
Cold forming, machining and welding with duplex-appropriate procedures
Solution anneal only when:
Material has been heavily hot worked, or
Very heavy cold work has been done and top-level toughness/corrosion resistance are required
Always finish with:
Proper pickling / mechanical cleaning + passivation to remove heat tint and contaminants and restore a clean passive surface.
Summary
S32101 (LDX 2101 / 1.4162) is not hardened by quenching; its key heat treatment is solution annealing at high temperature followed by rapid cooling to restore a balanced duplex microstructure, toughness and corrosion resistance after heavy hot or cold work, while routine welded and formed fabrications are usually left in the as-welded, solution-annealed condition with no further heat treatment—provided that duplex-specific welding and thorough post-weld cleaning are correctly applied.
Cold Working
Cold Working of S32101 (LDX 2101 / 1.4162) Stainless Steel
S32101 (LDX 2101 / 1.4162) is a lean duplex stainless steel with higher strength and lower ductility than 304/316, but it still offers good cold formability for sensible bend radii and moderate forming operations when correct tooling and procedures are used.
1. General Cold Workability
Duplex structure and higher yield strength mean forming loads are significantly higher than for 304/316.
Ductility is lower than austenitic grades, but adequate for most practical bending, rolling and profiling when radii and tooling are chosen appropriately.
Suitable for:
Rolling and bending of plate and sheet
Forming of channels, profiles, tanks and shells
Moderate flanging and edge-forming operations
2. Bending, Rolling and Forming Practice
Use larger minimum bend radii than you would for 304/316 to avoid edge cracking.
Apply forming in gradual steps rather than single severe hits, especially on thicker sections.
Ensure:
Smooth, well-polished tools
Good lubrication to reduce friction and galling
Proper alignment and support to avoid local over-strain
For difficult shapes or tight bends on thicker plate, consider:
Stepwise forming
Trial pieces to confirm radii and spring-back
Supplier guidance for recommended minimum radii by thickness
3. Work-Hardening and Residual Stresses
S32101 work hardens under cold deformation, but generally less aggressively than austenitic 304/316.
Effects of heavy cold work:
Increased strength and hardness in deformed zones
Reduced local ductility and toughness
Introduction of residual stresses, which can influence:
Distortion during/after welding
Fatigue and corrosion-fatigue behaviour
For demanding service (pressure, fatigue, corrosive media), avoid very severe local cold deformation unless you plan for corrective heat treatment.
4. Heavy Cold Work and Optional Solution Annealing
For light to moderate cold work (normal tank/pipe forming, reasonable bend radii), final solution annealing is usually not required, provided welding and cleaning are done correctly.
For heavy cold work, such as:
Very tight-radius bends on thick plate
Large area high-strain stretch forming or deep drawing
Significant cold reduction in thickness or diameter
a solution anneal + rapid cooling may be advisable to:Restore toughness
Rebalance the duplex microstructure
Recover best corrosion resistance (especially in chloride service)
5. Interaction with Welding and Machining
Cold-worked areas can:
Distort more when welded due to residual stresses
Show slightly different heat-affected behaviour than lightly worked base metal
Practical approach:
Do most heavy forming before critical welding.
Use balanced forming and machining to reduce distortion.
For high-accuracy parts, a route like
Form → Weld → Straighten (light) → Finish machine / grind
helps control final dimensions and stress state.
6. Design Recommendations for Cold-Worked S32101 Components
Assume higher forming forces and plan press/roll capacity accordingly.
Avoid:
Sharp corners and very tight radii in heavily loaded or corrosive-zone areas
Severe local thinning (necking) in high-stress regions
In critical applications (e.g. structural, pressure, seawater service):
Keep cold strain moderate and well distributed.
Consider solution annealing after extreme forming steps if top-level toughness and corrosion resistance are required.
Summary
S32101 (LDX 2101 / 1.4162) has good but not “304-like” cold workability: it can be bent, rolled and formed successfully when you allow for its higher strength with larger radii, higher forming loads and good lubrication; moderate cold work is normally acceptable without further heat treatment, while very heavy deformation should be followed by solution annealing or carefully limited, especially for critical, highly stressed or corrosion-exposed components.
