304 Stainless Steel Rod Supplier
MTS supplies 304 and 304L stainless steel rod, cold drawn, ground, polished or forged black. Diameters run from 3 mm to 300 mm, and inch sizes from 1/8” up.
304 and 304L to ASTM A276, A479 and EN 10088-3 (1.4301 / 1.4307)
Cold drawn bar to h9–h11; ground bar to h7/h8, Ra 0.2–0.8 µm
Square bar 10–100 mm and hex bar 8–120 mm in 304
Part of our 4,500 tons of stainless bar stock in Wuxi
Why Buy 304 SS Bar From Us
01
Drawn, Ground or Forged to Suit the Part
Cold drawn bar for general machining, ground bar for CNC precision parts, forged black bar up to Φ300 mm. One supplier covers the whole size range.
02
304 and 304L on One Certificate
304 bar can be supplied dual certified, meeting 304 strength and 304L carbon limits. You stock one item instead of two, and it welds without carbide trouble.
03
Stock in Wuxi for Fast Loading
304 round, square and hex bar in common sizes ship from our 4,500 tons of bar stock. Other sizes are produced to order.
04
Lengths That Fit Your Saw and Feeder
Standard lengths are 2, 3 and 6 m, with 9 m and 12 m on request. Ends are sawn square, so bars load cleanly in automatic lathes.
The Bar Most Parts Start With
304 contains about 18% chromium and 8% nickel. That mix resists rust in air, fresh water and most foods. It machines, welds and polishes without special handling.
That is why 304 stainless steel round bar is the starting point for fittings, fasteners, shafts and handrails. Move to another grade only when the part meets chlorides, needs hardness, or runs in high volume on a lathe.
304 Stainless Steel Bar Range
304 Stainless Steel Round Bar
Standard grade for general machined parts. Also listed as 304 stainless round bar or 304 ss round bar.
304L Stainless Steel Round Bar
Low carbon, 0.03% max. Choose 304L round bar for parts you weld and do not anneal afterward.
304H Round Bar
Carbon kept at 0.04–0.10% for strength above 500°C. Used for boiler and pressure parts to ASTM A479. Supplied by mill order.
302 Stainless Steel Round Bar
Slightly higher carbon than 304, for spring pins and cold-formed parts. Available on request.
304 Stainless Steel Shaft
Ground 304 bar to h7/h8, Φ5–30 mm, for pump, mixer and conveyor shafts. A 304 stainless steel ground shaft is ready to fit without turning.
Bars for Railing and Stairs
Polished or brushed 304 rod for balusters, infill bars and stair rail parts. Polished bar runs from Φ4 to Φ60 mm.
304 Square and Hex Bar
304 ss square bar from 10 to 100 mm and 304 stainless steel hex bar from 8 to 120 mm across flats, for nuts, fittings and decorative parts.
Specifications
| Item | Range |
|---|---|
| Grades | 304, 304L, 304/304L dual; 304H and 302 by order |
| Equivalents | UNS S30400 / S30403 / S30409; EN 1.4301 / 1.4307 / 1.4948; JIS SUS304 / SUS304L |
| Cold drawn bright bar | Φ3–100 mm; 1/8”–2” and up; h9–h11; Ra 1.6–6.3 µm |
| Ground bar | Φ5–30 mm; h7/h8; Ra 0.2–0.8 µm |
| Polished / large bright bar | Φ4–60 mm polished; Φ60–200 mm bright |
| Forged black bar | Φ200–300 mm; peeled on request |
| Square / hex bar | 10–100 mm square; 8–120 mm hex |
| Length | 2 m, 3 m, 6 m; 9 m and 12 m on request |
| Finish | Bright, ground, polished, pickled, brushed, black |
| Standards | ASTM A276, ASTM A479, EN 10088-3, JIS G4303 |
How to Choose and Specify 304 Stainless Steel Rod
Most 304 rod problems are not about the steel. They come from the wrong variant, the wrong condition, or a missing line on the order. This guide covers the decisions that matter.
304, 304L or 304H?
Standard 304 allows up to 0.08% carbon. When you weld it, carbon can join chromium at the grain boundaries. The weld zone then corrodes faster.
304L limits carbon to 0.03%. It avoids that problem, so pick it for welded frames, tanks and fittings. It is slightly weaker on paper, but dual-certified bar meets both specs.
304H goes the other way. Its carbon is kept at 0.04–0.10% to hold strength above about 500°C. Order a 304h round bar only for boiler, heat exchanger or pressure work that names it. For normal parts, it adds cost and nothing else.
Our advice: order 304/304L dual-certified bar unless your drawing says otherwise. It covers both cases at little or no extra cost.
What Cold Drawing Changes
Cold drawn 304 bar is stronger and more accurate than hot rolled bar. It also becomes slightly magnetic, because drawing turns some austenite into martensite.
For most parts, this does not matter. For sensors, medical parts or electronics housings, it can. State a maximum magnetic permeability on your order, so we can check the bar against it before shipping.
Cold drawn bar also carries some residual stress. If you turn deep slots on one side, the part can bow. For long, slender parts, ask for stress-relieved bar.
304 or 316 for Your Part?
304 holds up in indoor air, fresh water and food contact. Near the sea, in pools, or with de-icing salt, it can pit and stain.
If your part will see chlorides, move to SS 316 Rod. Molybdenum in 316 gives it much better pitting resistance. If it stays dry or indoors, 304 is the better-value choice.
304 Bar for Railing and Stairs
Railing infill and balusters are one of the largest uses of 304 rod. Most indoor stainless steel rods for stairs are 10 mm to 16 mm, or 3/8” to 1/2”.
For a stair rail or deck railing outdoors, think about location. Inland, polished 304 is fine with normal cleaning. Near the sea, use 316 instead. Tea staining on coastal 304 railing is the most common complaint we hear.
Order railing bar polished or brushed, with protective film or individual sleeves. Bar scratched in transit cannot be sold as finished railing.
304 Bar for Shafts
304 stainless steel shaft stock is common in food, pump and packaging machines. It resists washdown and does not need coating.
304 is not hardenable. For shafts that run in sleeve bearings or see wear, 304 can gall. In that case, a hardened 400 series grade such as 410 or 431 often lasts longer.
For fitted shafts, order ground bar to h7 or h8 and specify straightness. A 3/4” stainless steel shaft that is 0.5 mm out of straight over a meter will vibrate.
When 304 Is Not the Right Rod
Choose 303 when you turn high volumes on CNC lathes and do not weld. Choose 316L for chlorides. Choose 410 or 431 when you need hardness. Choose duplex when you need twice the yield strength.
In all other cases, 304 stainless steel rod remains the most practical choice.
Frequently Asked Questions
Is 304 stainless rod the same as SS304 rod?
Yes. SS304 rod, 304 ss rod and 304 stainless rod all mean the same grade. Its UNS number is S30400 and its EN number is 1.4301. Japanese drawings call it SUS304. Chinese mills may list it as 30401. Check the standard on your drawing, then order to that standard.
Can I get 304 and 304L on one certificate?
Yes. Dual-certified bar meets the chemistry of 304L and the strength of 304. The mill certificate lists both grades. Tell us when you inquire if you need it.
Can 304 stainless steel rod be hardened?
No, not by heat treatment. 304 only gets harder by cold working, such as drawing or rolling. If you need a hard surface or a hardened shaft, choose a martensitic grade like 410 or 420.
What tolerance should I order for 304 round bar?
Order h9 if the bar goes into a bar feeder or collet. Order h11 if you will turn the outside anyway. Order ground bar to h7 or h8 only for shafts fitted straight into bearings.
Do you work with distributors, like other SS 304 round bar suppliers?
Yes. We supply distributors and stockists with mixed sizes in one container, from our 4,500 tons of bar stock in Wuxi. Ask for our current stock list.
Is 304 rod suitable for food equipment?
Yes. 304 is the standard grade for food contact parts in most markets. It cleans easily and resists most food acids. For salty or acidic products, such as brine or tomato, 316L lasts longer.
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