303
Free-machining route
Frequently used for turned, threaded and machined components when machinability is a primary requirement and the service environment permits it.
Product form hub · Hex bar
Stainless Steel Hex Bar
Specify stainless steel hex bar by grade, across-flats size, production route, tolerance, finish, straightness and length. Use the size references and selection notes below to turn a general request into a clear purchasing specification.
303 / 304 / 316 / 316L
ASTM A276 / A484 route
Cold drawn, hot finished or machined
Solid hexagonal bar · product visual
Common grades303 / 304 / 316 / 316L
Common market size6 to 100+ mm A/F
Common lengths3 / 4 / 6 m and cut length
Build the specification
01Choose grade
02Set square size
03Choose bar route
04Define tolerance / finish
05Confirm length / edge condition
06Send RFQ
Product overview
What to define before buying stainless steel hex bar
Hex bar is normally specified by its across-flats (A/F) dimension. A clear order should also define grade, production route, dimensional tolerance, edge/edge condition, finish, straightness and length. These details matter when the bar will be turned, threaded, milled, welded or used for nuts, fittings and machined components.
Material304 / 304L
Common for general fabrication, fittings, machined parts and corrosion-resistant hardware.
Material316 / 316L
Frequently selected where chloride exposure, washdown or more demanding corrosion resistance is expected.
GeometrySide × side
Specify the solid square section directly, for example 25 × 25 mm or simply 25 mm square.
Bar routeCold drawn, hot finished or machined
The production route affects edges, straightness, surface appearance, dimensional tolerance and machining allowance.
M03 · Grade selection
Choose the grade from corrosion, fabrication and service needs
Hex bar is commonly sawn, drilled, turned, milled or welded after purchase. Grade selection should consider corrosion exposure, fabrication, machining and the final service environment rather than only the nominal alloy name.
304 / 304L
General-purpose austenitic
Common for fastener stock, fittings, fabricated components and general corrosion-resistant machining.
316 / 316L
Higher corrosion resistance
Often selected for marine-adjacent, chemical, food-process and washdown applications where chloride resistance is more important.
416 / 410
Machining / higher hardness route
Martensitic routes are used for selected machined parts where hardness, strength or machinability is more important than maximum corrosion resistance.
M04 · Technical data
Common stainless steel hex bar size reference
The table below uses common commercial hex-bar sizes for early design and RFQ preparation. Exact availability depends on grade, production route, finish, tolerance and order quantity.
| Across flats (A/F) | Common grade routes | Typical production route | Common length reference | Buying note |
|---|---|---|---|---|
| 6 mm | 303 / 304 | Cold drawn / cold finished | 3–6 m | Small hardware and precision turned parts |
| 8 mm | 303 / 304 / 316 | Cold drawn / cold finished | 3–6 m | Common small-section hex stock |
| 10 mm | 303 / 304 / 316 / 316L | Cold drawn / cold finished | 3–6 m | Fittings, fasteners and machined components |
| 12 mm | 303 / 304 / 316L | Cold drawn / cold finished | 3–6 m | General-purpose machining size |
| 14–16 mm | 303 / 304 / 316 / 316L | Cold drawn | 3–6 m | Common for nuts, fittings and turned components |
| 17–19 mm | 303 / 304 / 316L | Cold drawn / bright finished | 3–6 m | Common metric tooling and fitting sizes |
| 22–24 mm | 303 / 304 / 316 / 316L | Cold drawn / hot finished | 3–6 m | Medium-section machining stock |
| 27–32 mm | 304 / 316 / 316L / 303 | Cold drawn / hot finished | 3–6 m | Confirm A/F tolerance and straightness |
| 36–41 mm | 304 / 316 / 316L | Cold drawn / hot finished | 3–6 m | Fittings, valve parts and heavy machined components |
| 46–50 mm | 304 / 316 / 316L | Hot finished / selected cold-finished routes | 3–6 m | Production route becomes more important |
| 55–75 mm | 304 / 316 / 316L / selected grades | Hot finished / forged / machined | Supplier-dependent | Confirm machining allowance and dimensional tolerance |
| 80–100+ mm | 304 / 316L / project grades | Hot finished / forged / machined from larger stock | Supplier-dependent | Large hexagonal sections are typically project-specific |
Market reference: stainless hex bar is commonly specified by the across-flats dimension, with small and medium sections often cold drawn for better dimensional consistency and larger sections supplied by hot-finished, forged or machined routes. State A/F size, grade, production route, length and any critical tolerance in the RFQ.
M05 · Dimensions and finish
Define the square size, route and edge condition
Hex bars with the same nominal A/F size can differ in tolerance, edge definition, straightness and surface condition depending on whether they are cold drawn, hot finished, forged or machined.
Dimensions
- Across-flats (A/F) dimension
- Standard length or cut length
- A/F tolerance if critical
- Straightness requirement for machining
- Edge / edge condition if assembly-critical
Production route
- Cold drawn / cold finished hex bar
- Hot-finished hex bar
- Forged or machined large-section hex bar
- Ground or machined precision stock
- Cut-to-length or sawn blanks
Surface & processing
- Hot-finished / pickled surface
- Bright cold-finished surface
- Ground / machined flats where specified
- Saw cut / drilled / milled processing
- Protected packing for finished surfaces
M06 · Selection guide
Match the hex-bar route to the machining and service requirement
General machining / fabrication304 / 304L is a common starting point for corrosion-resistant fittings, hardware and fabricated components in moderate environments.
High-volume machining303 or other free-machining routes can reduce machining effort where their corrosion and service properties are acceptable; verify the applicable material specification.
Coastal / chloride exposure316 / 316L is commonly considered where chloride exposure or washdown is more demanding than a general indoor environment.
Large section / heavy partHot-finished, forged or machined hex stock may be more practical at larger A/F sizes; specify machining allowance and final dimensional requirements.
Worked example
Example of a clear hex bar specification
A usable request defines the solid square section, bar route and downstream processing requirements instead of ordering only by grade and nominal size.
Example only
This is a normal buying example, not a live-stock claim. Final requirements should follow the project drawing, service environment and machining plan.
ProductStainless steel hex bar
Standard routeASTM A276/A276M with ASTM A484/A484M general requirements
Grade316L
Size24 mm A/F
Production routeCold drawn / cold finished
Length6 m or cut-to-length as required
Order requirementState quantity, destination, tolerance, cutting and document requirements in the RFQ
M08 · Applications
Where stainless steel hex bar is commonly used
Machined components
Turned fittings, valve parts, spacers, connectors, stems and custom precision components.
Fasteners & nuts
Hex stock is a practical starting form for nuts, threaded parts, standoffs and special fasteners.
Instrumentation fittings
Machined bodies, adapters and connection components where defined flats simplify wrench engagement.
Food & process equipment
316 / 316L hex stock is used for selected fittings, hardware and machined process-equipment components.
Marine / outdoor hardware
316 / 316L hex bar is often considered for more demanding chloride and outdoor exposure.
General engineering
Jigs, fixtures, keys, supports and custom parts produced from solid square stainless stock.
Important limitation: nominal square size alone does not define the finished part. Hot-rolled, cold-drawn and forged routes can differ in corner radius, dimensional tolerance, straightness, surface scale and machining allowance. If the bar will be precision-machined or used in a close-fitting assembly, state the required route and tolerance on the RFQ.
M10 · Standards
Standards and purchasing references
Use the latest project-approved revision and state it on the purchase specification. Standard numbers below are shown as technical references only.
Common stainless bar-and-shape specification covering hot-finished or cold-finished bars in widely used stainless grades.
General requirements for wrought stainless bars, billets, shapes and forgings, including dimensional and ordering controls used with product specifications.
Reference for free-machining stainless bars such as selected 303 / 416 routes, including round, square and hexagon forms intended for machining.
M11 · FAQ
Stainless steel hex bar FAQ
How is stainless steel hex bar sized?
Hex bar is normally specified by its across-flats (A/F) dimension and length, for example 24 mm A/F × 6 m. Add grade, production route, tolerance, finish and straightness where they matter.
What grades are common for stainless hex bar?
304 / 304L and 316 / 316L are common corrosion-resistant routes. 303 is widely used where machinability is a priority, while selected martensitic free-machining grades such as 416 may be used for parts needing different strength or machining characteristics.
What is the difference between 303 and 304 hex bar?
303 is designed for improved machinability, while 304 is generally preferred when broader corrosion resistance and welding behavior are more important. The correct choice depends on the finished part and service environment.
Is cold-drawn hex bar better for machining?
Cold-drawn or cold-finished hex bar typically offers better dimensional consistency, straighter stock and a cleaner surface than rougher hot-finished routes, which can reduce machining allowance for many parts.
Which standards are commonly referenced for stainless hex bar?
ASTM A276/A276M is commonly referenced for non-free-machining stainless bars and shapes, ASTM A484/A484M provides general requirements, and ASTM A582/A582M covers free-machining stainless bars.
Product details
What buyers usually verify visually
Review representative hex-bar inspection, machining and packing evidence before finalizing the purchase specification.
Square geometry & cornersAcross-flats dimension, flat-to-flat geometry, corner radius and straightness
Surface & bar routeBright cold-drawn, hot-finished, machined or ground appearance
Cut length & packingSawn ends, bundled bars and protection for finished surfaces
Hex bar resources
Continue from specification to purchase
Material hub
Stainless Steel
Review the parent material hub and related stainless steel product forms.
Open stainless steel hub → Technical Technical ResourcesUse standards, comparisons and engineering references to clarify the purchase specification.
Open technical resources → Sourcing Request a QuoteMove from a reviewed specification to a purchasing conversation.
Open RFQ page →M13 · Technical reference
Reference basis for this hex bar guide
The page uses ASTM A276/A276M bar-and-shape requirements, ASTM A484/A484M general requirements, ASTM A582/A582M for free-machining stainless bars, and common commercial stainless hex-bar size patterns. Exact A/F size, tolerance, finish, straightness and certification should be confirmed for the actual order.
M14 · RFQ
Request a technical quote
For a faster review, include the grade, square size, production route, tolerance or finish, length, quantity, destination and any cutting, machining or document requirement.
- Grade / material designation
- Square size / across-flats dimension
- Production route, A/F tolerance and finish
- Length / cutting / machining requirement
- Quantity, destination and required documents