321 Stainless Steel Square Bar
Short Description:
Titanium-stabilized 321 stainless steel square bar for machined parts and fabricated equipment components. Common enquiry sizes include 10 × 10 to 100 × 100 mm, with 3,000, 5,800 and 6,000 mm length references and cut-length requirements. Specify the standard, finish, tolerances and quantity for quotation.
321 Stainless Steel Square Bar
321 square bar is a solid square-section material in
titanium-stabilized austenitic stainless steel. Its flat faces
provide a practical starting form for machined blocks, spacers,
brackets and fabricated equipment components.
Titanium stabilization helps reduce susceptibility to
sensitization and intergranular corrosion. Select the grade,
delivery condition and product standard for the actual fabrication
and service environment.
the grade or a supplied production batch.
Relevant Standards and Grade Designations
| Reference | Application to this product | Ordering point |
|---|---|---|
| 321 / UNS S32100 | Grade and material identifier | A grade name alone does not define finish, tolerances or complete delivery requirements. |
| ASTM A276/A276M | Stainless steel bars and shapes, including square bars | State the edition, condition and unit system. |
| ASTM A479/A479M | Bars and shapes for boiler and pressure-vessel construction | Use when required by the equipment specification. |
| EN 10088-3 / 1.4541 / X6CrNiTi18-10 | European long-product specification and commonly compared material designation |
Review chemistry, condition and mechanical requirements; do not assume automatic dual certification. |
| JIS G 4303 / SUS321 | Japanese stainless steel bar reference | Specify the required JIS grade, product condition and edition. |
These references are alternatives to identify in the order, not a
statement that every bar is certified to all listed standards.
Confirm the applicable requirements before placing the order.
Product Specifications and Common Order Sizes
| Item | Specification |
|---|---|
| Product form | Solid square bar, a × a |
| Grade | 321 / UNS S32100 |
| Common side-size references | 10, 12, 15, 16, 20, 25, 30, 40, 50, 60, 80 and 100 mm |
| Length references | 3,000 / 5,800 / 6,000 mm; cut lengths to order |
| Finish and condition | Specify hot-finished/pickled, cold-drawn/bright, ground or polished requirements and the required heat treatment |
| Critical geometry | Side tolerance, squareness, straightness, corner radius and cut-length tolerance |
| Special requirements | Other dimensions, lengths and drawing requirements can be discussed with the enquiry |
The sizes above are common enquiry references, not a stock list
or a maximum supply envelope. Specify machining allowance separately
from the finished component dimensions.
Chemical Composition Reference
The table below follows the published cast-analysis reference for
Rodacciai 321 / 1.4541 bar material. It is identified here as a material
reference, not as a reproduction of ASTM A276 acceptance limits.
The purchase standard and supplied heat analysis govern acceptance.
| Element | Mass % |
|---|---|
| Carbon, C | 0.08 max. |
| Silicon, Si | 1.00 max. |
| Manganese, Mn | 2.00 max. |
| Phosphorus, P | 0.045 max. |
| Sulfur, S | 0.030 max. |
| Chromium, Cr | 17.00–19.00 |
| Nickel, Ni | 9.00–12.00 |
| Titanium, Ti | 5 × C min.; 0.70 max. |
Source:
Rodacciai 321 / 1.4541 bar datasheet.
Nitrogen is not separately listed in this source table; this does
not mean zero nitrogen. Titanium and nitrogen acceptance must follow
the specified product standard and edition.
Mechanical and Physical Properties
The mechanical reference below applies to comparable EN 1.4541
annealed long products up to 160 mm, at room temperature, using
longitudinal test specimens. It is not a guarantee for every size,
cold-worked condition or ASTM order.
| Property | Reference value | Basis |
|---|---|---|
| 0.2% proof strength | 190 MPa min. | Annealed long-product reference |
| Tensile strength | 500–700 MPa | Annealed long-product reference |
| Longitudinal elongation | 40% min. | Annealed long-product reference |
| Density | Approximately 7.9 g/cm³ | Physical reference near 20°C |
| Elastic modulus | Approximately 200 GPa | Physical reference near 20°C |
| Thermal conductivity | Approximately 15 W/(m·K) | Physical reference near 20°C |
Source:
thyssenkrupp 321 / 1.4541 material data.
Cold work, section size and test direction affect mechanical properties.
Specify contractual values in the order.
Dimensions and Theoretical Weight
For a nominal square side a in millimetres,
theoretical weight is 0.0079 × a² kg/m, using
7.9 g/cm³ density. Multiply kg/m by the ordered length in metres
to estimate piece weight.
| Side × side, mm | Approx. kg/m | Approx. kg per 3 m | Approx. kg per 6 m |
|---|---|---|---|
| 10 × 10 | 0.790 | 2.370 | 4.740 |
| 12 × 12 | 1.138 | 3.413 | 6.826 |
| 15 × 15 | 1.778 | 5.333 | 10.665 |
| 20 × 20 | 3.160 | 9.480 | 18.960 |
| 25 × 25 | 4.938 | 14.813 | 29.625 |
| 30 × 30 | 7.110 | 21.330 | 42.660 |
| 40 × 40 | 12.640 | 37.920 | 75.840 |
| 50 × 50 | 19.750 | 59.250 | 118.500 |
| 60 × 60 | 28.440 | 85.320 | 170.640 |
| 80 × 80 | 50.560 | 151.680 | 303.360 |
| 100 × 100 | 79.000 | 237.000 | 474.000 |
Figures are rounded independently from the formula. Actual weight
varies with tolerances and corner geometry. A nominal 25 mm square
does not define a finished 25 mm machined part without allowance.
Confirm Your Square Bar Requirements
Inspection, Processing and Packing
Prepare the quotation around the required full lengths, cut
pieces or drawing. Agree inspection scope, identification and
protective packing before ordering.
- Material: check the specified grade,
heat number, chemistry and required mechanical results. - Dimensions: define both side dimensions,
straightness, squareness, corners and cut-length tolerance. - Surface: state finish and machining allowance;
protect critical surfaces from handling damage. - Additional tests: specify PMI, NDT or corrosion
examination, including method, coverage and acceptance criteria,
when required. - Packing: agree wrapping, bundles or cases,
lifting arrangements and identification suitable for the shipment.
Inspection photographs illustrate activities or product form;
acceptance is established by the order requirements and applicable
inspection records.
report or a guaranteed tolerance.
Applications and Important Buying Notes
Typical square-bar starting parts include machined spacers,
mounting blocks, brackets and supports for fabricated equipment.
Use grade 321 where the material selection calls for a
titanium-stabilized austenitic stainless steel.
- Thermally cycled equipment: review temperature,
exposure duration, loading and process medium. - Welded assemblies: specify the welding procedure
and post-fabrication cleaning requirements. - Machined components: allow for work hardening,
cutting allowance and final surface requirements.
321 does not automatically replace 304, 316L or 321H.
Titanium stabilization does not provide universal resistance to
chloride attack. For creep-governed service, confirm the required
grade and design-code properties; an oxidation-temperature figure
is not an allowable working temperature.
Frequently Asked Questions
How should I specify the dimensions?
Use side × side × length, such as
25 × 25 × 3,000 mm. Add side and length tolerances, straightness,
corner requirements and machining allowance.
Is this square tube?
No. Square bar is solid. Square tube is hollow
and also requires a wall-thickness specification.
Are 321, 1.4541 and SUS321 interchangeable?
They are commonly compared designations.
The required chemistry, condition, mechanical properties and
product standard must still be checked. State any dual-certification
requirement explicitly.
Does a bright surface mean tighter tolerances?
Surface appearance alone does not define
dimensional tolerance. Specify the delivery route, side tolerance,
straightness and surface acceptance requirements.
Can 321 be hardened by heat treatment?
321 gains strength through cold work rather
than conventional quench hardening. Order the condition and
mechanical properties required for the component.
Can I enquire about sizes outside the table?
Yes. The table lists common references.
Send other side dimensions, cut lengths, tolerances and quantities;
include a drawing for critical geometry.
Request a Quote for 321 Square Bar
Use the existing product enquiry form and include:
- Grade and product standard, including edition
- Side × side × length and quantity
- Delivery condition, finish and tolerances
- Machining allowance or component drawing
- Inspection, documents, packing and destination
A complete specification helps align
material, processing and inspection requirements in the quotation.
