Stainless Steel Round Bar
Shafts, pins, spacers, and turned fittings start as round bar. You order it by diameter, grade, and cut length.
Raw Materials
Stainless Steel Bars
Profab Machine supplies 304, 316L, and 17-4PH stainless steel bars in round, square, hex, and flat sections. We cut each bar to your length on our own saws. If you have a drawing, we machine that bar to it. Either way, send the grade, the size, and the cut length you need.
At a Glance
- Shapes
- Round, square, hex, flat
- Grades
- 304, 316L, 17-4PH
- Supplied
- Cut to your length
- Machining
- To your drawing
- Sample lead time
- About 20 days
Product Range
Types of Stainless Steel Bars
Bars are specified by shape first and by supplied condition second.
Stainless Steel Square Bar
Keys, guides, and blocks are milled from square bar. The size is the side of the square.
Stainless Steel Hex Bar
Standoffs and fittings with wrench flats are turned from hex bar. The size is measured across flats (AF).
Stainless Steel Flat Bar
Brackets, straps, and base plates are cut and milled from flat bar. You order it by thickness, width, and length.
By Bar Condition
The condition sets the surface, the diameter tolerance, and how much material you remove in machining.
Hot-Rolled Black Bar
Hot rolling leaves black bar with a dark, scaled surface and more diameter variation than bright bar. That makes it a fit for parts machined all over.
Bright Cold-Drawn Bar
Cold drawing at room temperature gives bright bar a smooth surface and a closer diameter tolerance. Shafts and pins made from it need less turning.
Centerless Ground Bar
Grinding holds centerless ground bar to a close diameter. That fits shafts that run in a bushing or bearing.
Passivation and electropolishing are available on request when the finished part needs a cleaner surface.
Material Specification
Choosing the Right Grade
The grade you pick depends on the water, the salt, and the load around the part.
304 / 304L
304 stainless steel bar works for shafts and pins in indoor machinery, automation, and dry or mildly humid areas. Choose 304L if the part will be welded and not annealed afterwards. Continuous salt spray or chloride washdown is beyond what 304 can handle.
316 / 316L
316 and 316L stainless steel bar contain 2 to 3 percent molybdenum, which gives better chloride pitting resistance than 304. Choose them for marine pins, pump shafts in wet service, and parts washed with chloride-based cleaners.
17-4PH
17-4PH stainless steel bar is a precipitation-hardening grade. Aged to H900, it has a minimum tensile strength of 1,310 MPa, against 515 MPa for annealed 304 or 316. That strength comes with lower toughness than the H1150 condition, so H900 fits only where load matters more than toughness.
Other grades are available on request: 303 for easier machining, 321, and duplex 2205 and 2507.
Applications
Diverse Applications of Stainless Steel Bars
Bar is rarely used as supplied. These are machined parts that start as stainless steel bar.
Food Plant Conveyor Shafts
Mixer shafts and conveyor roller shafts are turned from 304 stainless steel round bar, because washdown water rules out carbon steel.
Marine Deck Hardware Pins
Deck hardware pins and small shafts are machined from 316L stainless steel round bar, because salt spray corrodes carbon steel and 304.
Pump Shafts and Valve Stems
Pump shafts and valve stems are turned from stainless steel round bar, in 316L for chloride resistance or 17-4PH for strength under load.
Selection Guide
How to Specify Stainless Steel Bars
Check these points before you request a quote.
| Factor | What to Specify | Why It Matters |
|---|---|---|
| Shape | Round, square, hex, or flat | The shape decides how much material is removed in machining. |
| Size | Diameter, across flats, or thickness × width | Round bar is ordered by diameter, hex bar by across-flats width, and flat bar by thickness and width. |
| Grade | 304 or 304L, 316 or 316L, 17-4PH, or another stainless grade | Name the full grade, and for 17-4PH the aged condition. |
| Condition | Hot-rolled, bright cold-drawn, or centerless ground | The condition sets the surface and the diameter tolerance. |
| Cut length | Finished length, and whether the ends are machined afterwards | The ends need extra length if they are faced. |
| Machining | Turning, milling, grinding, drilling, tapping | State the finished part, not only the bar. |
| Finish | As supplied, passivated, or electropolished | Process lines often need the cleaner surface. |
| Quantity | Pieces or meters, and prototype or production | Prototype and production runs are quoted separately. |
Typical Bar Sizes
Common sizes by shape. Other sizes are quoted from your drawing.
| Shape | Typical Size | Supplied As |
|---|---|---|
| Round bar | Diameter 3 to 80 mm in bright or ground condition, larger hot-rolled sizes on request | Cut to your length |
| Square bar | Side 5 to 100 mm | Cut to your length |
| Hex bar | Across flats 5 to 100 mm | Cut to your length |
| Flat bar | Thickness 3 to 100 mm, width 10 to 300 mm | Cut to your length |
Why Profab
Your Reliable Stainless Steel Bars Supplier
01
Direct from the Manufacturer
We cut the bars on our own saws. We CNC machine the parts ourselves, so you deal directly with the factory. Tiered pricing is available on larger orders.
02
Cut Lengths and Machined Parts on One Quote
Order bars cut to length, or order the finished shafts, pins, and spacers made from them. Both come on one quote and ship together.
03
Drawing Review Before Cutting
Our engineers check the grade, the size, and the tolerance against your drawing before cutting metal.
Build a Complete System
Parts We Machine from Stainless Steel Bar
These four pages cover parts we machine from bar.
Stainless Steel Spacers
Spacers are turned from round bar to your length, bore, and grade.
Learn More
Stainless Steel Bushings
Bushings are turned and bored from round bar for shafts and pins that run in a sleeve.
Learn More
Stainless Steel Clevis
We machine clevis ends from solid 304, 316L, or 17-4PH bar with matching pins.
Learn More
What is the difference between hot-rolled, bright, and centerless ground stainless steel bar?
Hot-rolled bar has a scaled surface and the widest diameter tolerance. Cold-drawn bright bar is smoother and holds a closer diameter. Centerless ground bar holds the closest diameter of the three.
Which grade should I order, 304, 316L, or 17-4PH?
Order 304 for indoor, dry service and 316L where salt or chloride cleaners are present. Order 17-4PH when the shaft or pin carries a high load, because aged 17-4PH has a minimum tensile strength of 1,310 MPa at H900.
Can I order finished shafts and pins instead of stainless steel bar?
Yes. We machine finished parts from bar to a dimensioned drawing in DXF, DWG, STEP, IGES, or PDF. The spacer, bushing, and clevis pages on this site show parts made this way.
What tolerance can I expect on stainless steel bar and on machined parts?
Bar tolerance depends on the condition: cold-drawn and ground bar hold a closer diameter than hot-rolled bar. On machined features we can work to ±0.01 mm, depending on the part, the grade, and the feature. State the tolerance on your drawing.
Is stainless steel bar magnetic?
Annealed 304 and 316 are essentially non-magnetic, but cold working or machining can make them slightly magnetic. 17-4PH is magnetic in every heat-treated condition. Magnetism is therefore not a test for grade.
How to Order
From Inquiry to Delivery
What to Send
- Shape: round, square, hex, or flat
- Size: diameter, across flats, or thickness × width
- Grade: 304, 316L, or 17-4PH
- Condition: hot-rolled, bright cold-drawn, or centerless ground
- Cut length, and whether the ends are machined
- Quantity, and whether it is a prototype or production run
- A drawing or sample for machined parts
- 1
Quote Within 24 Hours
Your quote arrives within 24 hours of your request.
- 2
Sample First on Machined Parts
New machined parts are sampled first, which takes about 20 days.
- 3
Production and Delivery
Standard lead time is 30 days. We ship by sea, air, or express courier with a tracking number.
We set no hard minimum order, so small quantities are fine.
Related Products
Often Ordered Together
Get in touch with
Ready to Order Stainless Steel Bars?
If you already have drawings, email them to [email protected].
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