Stainless Steel Round Bar

Circle H Steel Products is a stainless steel round bar supplier specializing in long-length bar stock for industrial manufacturers. We stock and distribute 303, 304, 316, and more in both standard and long-length sizes to help reduce scrap, minimize joints, and improve throughput. Pair your material with our value-added sawcutting, grinding/custom shafting, and heat treating services to receive bar stock that is closer to production-ready.

Although the corrosion resistance of stainless comes from the presence of Chromium, other elements are added to enhance different properties. These elements alter the microstructure of the steel. Stainless steels are grouped into families based on their metallurgical microstructure. The microstructure may be composed of the stable phases austenite or ferrite, a “duplex” mix of these two, martensite, or a hardened structure containing precipitated micro-constituents.

Austenitic Stainless Steels

Austenitic stainless steels contain a minimum of 16% chromium and 6% nickel. They range from basic grades like 304 through to super austenitic such as 904L and 6% Molybdenum grades. By adding elements such as Molybdenum, Titanium or Copper, the properties of the steel can be modified to perform at high temperatures with increased corrosion resistance. Most steels become brittle at low temperatures, but the Nickel in austenitic stainless steel makes it suited to low-temperature or cryogenic applications.              

Austenitic stainless steels are generally non-magnetic. They are not able to be hardened by heat treatment. Austenitic stainless steels rapidly work-harden with cold working. Although they work-harden, they are the most readily formed of the stainless steels. The principal alloying elements are sometimes reflected in the name of the steel. For example, a common name for 304 stainless steel is 18/8, for 18% chromium and 8% nickel.

Applications

• Kitchen sinks
• Architectural applications such as roofing 
• Roofing and gutters
• Doors and Windows
• Balustrading
• Benches and food preparation areas
• Food processing equipment
• Heat exchangers
• Ovens
• Chemical tanks

Ferritic Stainless Steels

Ferritic stainless steels include grades like 430 and contain only chromium as a major alloying element. The quantity of chromium present ranges from 10.5% to 18%. They are known for their moderate corrosion resistance and poor fabrication properties. Fabrication properties can be improved by alloy modifications and are satisfactory in grades such as 434 and 444.

Ferritic stainless steels cannot be hardened by heat treatment and are always used in the annealed condition. Ferritic stainless steels are magnetic. They are also not susceptible to stress corrosion cracking. Weldability is acceptable in thin sections but decreases as section thicknesses increase.

Ferritic stainless steels are typically used in:

• Vehicle Exhausts
• Fuel Lines
• Cooking utensils
• Architectural Trim
• Domestic Appliances

Martensitic Stainless Steels

High carbon and lower chromium content are the distinguishing features of martensitic stainless steels when compared with ferritic stainless. Martensitic stainless steels include 410 and 416. Hardened martensitic steels cannot be successfully cold formed. They are magnetic, have moderate corrosion resistance and poor weldability.

Martensitic stainless steels are typically used for:

• Knife blades
• Cutlery
• Surgical instruments
• Fasteners
• Shafts
• Springs

Duplex Stainless Steels

Duplex stainless steels have high chromium and low nickel contents. This gives duplex stainless steels microstructures that include both austenitic and ferritic phases. They include alloys like 2304 and 2205. These alloys are so named due to their respective compositions: 23% chromium, 4% nickel and 22% chromium, 5% nickel. By having both austenite and ferrite in the microstructure, duplex stainless steels feature properties of both classes. Although a compromise between the two ‘pure’ types, duplex grades can offer some unique property solutions.         

Duplex grades are resistant to stress corrosion cracking, but not to the same level as ferritic grades. The toughness of duplex grades is superior to that of the ferritic grades – but inferior to that of the austenitic grades. Most importantly, the corrosion resistance of duplex steels is equal to, or superior to, that of 304 and 316 stainless steel. This is particularly so for chloride attack. Duplex grades are readily welded. They also have high tensile strengths.

Duplex stainless steels typically find application in areas like:

• Heat exchangers
• Marine applications
• Desalination plants
• Food picking plants
• Off-shore oil and gas installations
• Chemical and petrochemical plant

Precipitation Hardening Stainless Steels

Precipitation hardening grades contain both Chromium and Nickel. They develop very high tensile strengths with heat treatment. Precipitation hardening grades are usually supplied in a “solution treated” condition that allows the steel to be machined. After machining or forming, the steel can be aged in a low-temperature heat treatment process.                     

As the heat treatment is performed at low temperatures, no distortion is induced in the workpiece. 630 is the most common precipitation hardening grade. This grade is also known as 17-4 PH due to a composition of 17% chromium, 4% nickel, 4% copper and 0.3% niobium

Precipitation-hardening stainless steels are typically used for:

• Pulp and paper industry equipment
• Aerospace applications
• Turbine blades
• Nuclear waste casks
• Mechanical components

The old AISI three digit stainless steel numbering system (e.g. 304 and 316) is still commonly used. New grades are defined under the SAE and ASTM system that uses a 1-letter + 5-digit UNS number. An example of this is the new term for 304, which is S30400. Other designations include old BS and EN numbers like 304S31 and 58E. Some grades are not covered by standard numbers and could be proprietary grades or be named using standards for specialist products like welding wire.

The grade selection process for stainless steels depends on the desired properties of the finished product. When selecting a particular grade of stainless steel bar, it’s essential to consider the properties required, such as:

• Corrosion resistance
• Heat resistance
• Machinability
• Weldability
• Formability 
• Surface finish
• Cost and availability

An example of this is 303 stainless steel. It has excellent machinability due to the addition of sulphur. However, the sulphur also gives 303 poor weldability, corrosion resistance, and formability. Selecting the correct grade will ensure the product will have a long trouble-free life combined with cost-effective fabrication and installation. 

As a stainless steel grades supplier, we are happy to help assist you with the grade selection process. 

Use our weight and conversion calculator to help estimate material needs once you've selected a grade, or request a quote directly from our team.

Circle H Steel Products makes it easy to source the right stainless steel round bar grade, size, and value-added service for your application. Request a quote today, or contact our team to discuss your project requirements.

What is stainless steel round bar used for? 

Stainless steel round bar is used in machined components, shafts, fasteners, and structural parts across marine, pump, valve, food processing, and wastewater industries. Grade selection depends on required corrosion resistance, strength, and machinability. Circle H Steel supplies round bar in 303, 304, 316, 410, 416, 17-4 PH, and Alloy 2205 duplex grades in long-length sizes.

What sizes does stainless steel round bar come in? 

Circle H Steel stocks stainless steel round bar in a range of standard diameters, plus specialty and custom sizes. Bar is also available in short-length (12 feet or under), standard mill lengths, and long-length options that exceed standard sizing. Visit our Sizes page to view available diameters for each grade.

What is long-length stainless steel bar?

Long-length stainless steel bar extends beyond standard mill lengths, giving manufacturers more usable material per piece. This reduces the number of bars a facility needs to stock, transport, and weld together, helping lower scrap rates and improve production throughput. Circle H Steel specializes in supplying long-length stainless round bar.

Which stainless steel round bar grade is easiest to machine?

Grade 303 offers the best machinability of common stainless grades due to added sulfur, making it a top choice for high-volume machined components like shafts and fittings. Grade 416 is a martensitic alternative also known for excellent machinability, though both trade off some corrosion resistance and weldability.