Chrome Manganese Austenitic Stainless Steel Seamless Pipe UNS S20100
Chrome-manganese austenitic seamless pipe is an economical alternative to traditional chromium-nickel austenitic stainless steels such as 304 and 316. This grade achieves a stable austenitic structure by substituting a portion of expensive nickel with more cost-effective manganese and nitrogen, delivering comparable mechanical properties at a significantly lower material cost.
The most common chrome-manganese austenitic grade is 201 stainless steel (UNS S20100), which typically contains 16-18% chromium, 3.5-5.5% nickel, and 5.5-7.5% manganese. The addition of nitrogen further stabilizes the austenitic phase and increases yield strength, making this grade particularly attractive for structural and general industrial applications where extreme corrosion resistance is not required.
The seamless manufacturing process ensures uniform wall thickness, consistent mechanical properties, and complete absence of a longitudinal weld seam. This seamless construction provides superior pressure-holding capability and reliability compared to welded pipes, making chrome-manganese seamless pipes suitable for a wide range of industrial, structural, and decorative applications.
| Parameter | Details |
|---|---|
| Product Name | Chrome-Manganese Austenitic Seamless Pipe |
| Common Grade | 201 (UNS S20100) |
| Alternative Grades | 202 (UNS S20200), 201L, 201LN |
| EN Equivalent | 1.4372 |
| Standards | ASTM A269, ASTM A213, ASTM A511, ASTM A312 |
| Form | Seamless Pipe / Seamless Tube (SMLS) |
| Manufacturing Process | Cold drawn or cold rolled seamless |
| Outer Diameter Range | 6mm – 219mm (1/4" to 8") |
| Larger Diameters | Up to 325mm (12") available upon request |
| Wall Thickness Range | 0.5mm – 15mm |
| Length | Single random (3-6m), double random (6-12m), or exact cut |
| Pipe Ends | Plain End (PE), Beveled End (BE), Threaded (T&C) |
| Surface Finish | Annealed & pickled, bright annealed, polished (180#, 240#, 320#, 400#, 600#) |
| Packing Method | Plastic end caps, steel strapping, waterproof paper interleaved, wooden crates for export |
| Certification | Mill Test Certificate EN 10204 Type 3.1 or 3.2 |
The chrome-manganese composition of grade 201 achieves austenitic stability through manganese and nitrogen rather than high nickel.
| Element | Content (% by weight) |
|---|---|
| Carbon (C) | 0.15 max |
| Manganese (Mn) | 5.50 – 7.50 |
| Silicon (Si) | 0.75 max |
| Phosphorus (P) | 0.045 max |
| Sulfur (S) | 0.030 max |
| Chromium (Cr) | 16.00 – 18.00 |
| Nickel (Ni) | 3.50 – 5.50 |
| Nitrogen (N) | 0.25 max |
| Iron (Fe) | Balance |
Alternative Chrome-Manganese Grades:
| Grade | Chromium % | Nickel % | Manganese % | Nitrogen % |
|---|---|---|---|---|
| 201 (UNS S20100) | 16-18 | 3.5-5.5 | 5.5-7.5 | 0.25 max |
| 202 (UNS S20200) | 17-19 | 4-6 | 7.5-10.0 | 0.25 max |
| 201L | 16-18 | 3.5-5.5 | 5.5-7.5 | 0.20 max (low carbon) |
| 304 (for comparison) | 18-20 | 8-10.5 | 2.0 max | 0.10 max |
Chrome-manganese austenitic seamless pipe (Grade 201) delivers the following mechanical properties in the solution annealed condition:
| Property | Required Value (Typical) |
|---|---|
| Tensile Strength | 515 MPa (75 ksi) min |
| Yield Strength (0.2% offset) | 275 MPa (40 ksi) min |
| Elongation (2" or 50mm) | 35% min |
| Hardness (Rockwell B) | 95 HRB max |
| Hardness (Brinell) | 210 HBW max |
| Modulus of Elasticity | 197 GPa (28,600 ksi) |
| Density | 7.8 g/cm³ (0.28 lb/in³) |
| Thermal Conductivity (100°C) | 15.1 W/m·K |
| Specific Heat (0-100°C) | 500 J/kg·K |
| Electrical Resistivity | 720 μΩ·m |
Comparison with 304 Stainless Steel:
| Property | Chrome-Manganese 201 | 304 Stainless |
|---|---|---|
| Tensile Strength | 515 MPa min | 515 MPa min |
| Yield Strength | 275 MPa min | 205 MPa min |
| Elongation | 35% min | 40% min |
| Hardness | 95 HRB max | 92 HRB max |
| Work Hardening Rate | Higher | Lower |
| Relative Cost | 60-70% | 100% |
The higher yield strength of chrome-manganese grade often allows for reduced wall thickness in structural applications, further enhancing the cost advantage.
The seamless manufacturing process for chrome-manganese austenitic pipes ensures consistent quality and dimensional accuracy.
Step 1 – Billet Piercing
Solid round billets of chrome-manganese composition are heated and pierced to form a hollow shell.
Step 2 – Cold Drawing
The hollow shell is drawn through a die and over a mandrel at room temperature. Multiple cold drawing passes with intermediate annealing are used to achieve precise outer diameter and wall thickness.
Step 3 – Solution Annealing
The pipe is heated to 1010-1120°C (1850-2050°F) and then rapidly cooled (water or air quenched) to dissolve carbides, restore corrosion resistance, and achieve the required mechanical properties.
Step 4 – Pickling or Bright Annealing
Scale and oxide layers are removed through acid pickling, or the pipe is bright annealed in a controlled hydrogen or nitrogen atmosphere for a clean, reflective surface.
Step 5 – Straightening and Cutting
The pipe is straightened using rotary straighteners, cut to specified lengths, and ends are finished as required.
Step 6 – Final Inspection
Dimensional checks, surface inspection, and non-destructive testing are performed before packaging.
| Finish | Code | Description | Typical Application |
|---|---|---|---|
| Annealed & Pickled (AP) | AP | Scale removed by acid bath, matte gray appearance | General industrial piping |
| Bright Annealed (BA) | BA | Oxide-free, bright reflective surface achieved through controlled atmosphere annealing | Clean applications, food contact, decorative |
| Polished 180# | #180 | Mechanically polished, medium matte finish | Industrial equipment, furniture |
| Polished 240# | #240 | Fine matte finish | Architectural trim |
| Polished 320# | #320 | Very fine matte finish | Decorative applications |
| Polished 400# | #400 | Near-mirror finish | High-end decorative, automotive trim |
| Mirror Polish (600#+) | #600+ | Highly reflective mirror finish | Elevator interiors, luxury architectural |
Chrome-manganese austenitic seamless pipes are used across a wide range of industries where cost-effective corrosion resistance is sufficient.
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Handrails, balustrades, and guardrails
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Structural frames and building supports
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Decorative tubing for hotel and commercial interiors
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Furniture frames (chairs, tables, shelving)
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Stadium and arena seating structures
The higher yield strength allows for lighter sections while maintaining structural integrity.
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Exhaust system components (mild service conditions)
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Trim, molding, and decorative parts
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Fluid transfer lines for non-corrosive media
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Bus and train handrails
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Trailer and truck body components
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Conveyor rollers and material handling equipment
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Machine guards, safety cages, and frames
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Drying and baking oven components
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Heat exchanger tubing (moderate temperature)
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Roller tubes for printing, textile, and paper industries
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Food preparation equipment (non-acidic foods)
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Commercial kitchen equipment and work tables
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Brewery and dairy equipment (limited acid exposure)
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Beverage dispensing equipment
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Freshwater plumbing and distribution systems
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Water treatment equipment (mild conditions)
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Irrigation system components
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Well casing (non-corrosive water)
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Instrumentation and control lines
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Hydraulic and pneumatic tubing (non-critical)
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Piping for compressed air systems
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Structural tubing for machinery frames
For inquiries, technical data sheets, or a quotation for chrome-manganese austenitic seamless pipe (201 seamless pipe / low-nickel stainless steel seamless pipe), please contact our sales team.
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