ASTM A240 SS 309 Specifications | SS 309 Plate Standards

Stainless Steel 309 Plates are widely used for applications that require high-temperature strength, oxidation resistance, corrosion resistance, and reliable performance in demanding industrial environments. When purchasing or specifying SS 309 Plates, understanding the applicable material standards, chemical composition, mechanical properties, dimensions, finishes, and equivalent grades is important.

The most commonly referenced specification for Stainless Steel 309 Plates is ASTM A240 / A240M. This specification covers chromium and chromium-nickel stainless steel plate, sheet, and strip intended for pressure vessels and general applications.

This guide explains ASTM A240 SS 309 specifications, including SS 309 plate standards, UNS S30900, 1.4828 stainless steel, 309S and 309H grades, chemical composition, mechanical properties, available dimensions, surface finishes, and common applications.

What Is Stainless Steel 309?

Stainless Steel 309 is an austenitic chromium-nickel stainless steel grade developed for applications where higher temperature resistance is required. Its relatively high chromium and nickel content provides good corrosion resistance and excellent resistance to oxidation at elevated temperatures.

SS 309 Plates are available in different sizes, thicknesses, finishes, and forms depending on the application. They are commonly specified for furnace equipment, heat exchangers, boiler components, kiln linings, oven components, firebox applications, and other high-temperature equipment.

Depending on the market and specification requirement, Stainless Steel 309 may also be identified by designations such as UNS S30900, AISI 309, and W.Nr. 1.4828.

ASTM A240 SS 309 Plate Standard

ASTM A240 / A240M is one of the primary standards used for stainless steel plate, sheet, and strip made from chromium and chromium-nickel stainless steels. Stainless Steel 309 Plates manufactured according to ASTM A240 are commonly supplied for general industrial applications and pressure-related applications where the specification is applicable.

For engineering and procurement purposes, buyers may specify the material as ASTM A240 Type 309 Stainless Steel Plate or ASTM A240 SS 309 Plate.

ASME SA240 Stainless Steel 309 Plates

ASME SA240 is the corresponding ASME specification commonly referenced when Stainless Steel 309 Plates are required for applications covered by the ASME Boiler and Pressure Vessel Code.

Therefore, depending on the project requirement, the material specification may be written as ASTM A240 / ASME SA240 Stainless Steel 309 Plate.

ASTM A167 Stainless Steel 309

ASTM A167 was a former specification associated with stainless and heat-resisting chromium-nickel steel plate, sheet, and strip. For current procurement, the applicable project, material, and edition requirements should always be checked before specifying an older standard.

SS 309 Plate Equivalent Grades and Designations

Stainless Steel 309 can have different designations depending on the standard system or country. These equivalent designations help buyers, engineers, and procurement teams identify the same or closely corresponding material across international specifications.

Standard System	Designation	Material Number / Equivalent
UNS	UNS S30900	S30900 – Stainless Steel 309
UNS	UNS S30908	309S
UNS	UNS S30909	309H
EN / DIN	EN 10095 / EN 10088-2 / DIN	1.4828
EN / DIN	309S	1.4833
JIS	JIS G4304 / JIS G4305	SUS 309 / SUS 309S
BS	British Standard	309S24 / 309S16
AFNOR	NF A 35-578	Z15CNS20.12 / Z17CNS20-12
GB / GB/T	GB/T 4237 / GB/T 3280	1Cr20Ni14Si2 / 20Cr23Ni13
GOST	GOST 5632	20Kh20N14S2 / 20Kh23N13
SS / SIS	SS 14 2372	SS 2372
ČSN	ČSN 17251	17251

UNS S30900 Stainless Steel Plates

UNS S30900 is the Unified Numbering System designation commonly associated with Stainless Steel 309. Buyers may therefore search for or specify the material using terms such as UNS S30900 Plates, UNS S30900 Stainless Steel Plate, or S30900 SS Plate.

When sourcing Stainless Steel 309 Plates, it is important to confirm the exact UNS designation, applicable ASTM specification, thickness, width, length, finish, and testing requirements stated in the purchase order.

1.4828 Stainless Steel Plates

1.4828 stainless steel is another commonly used designation associated with Stainless Steel 309. In European and international markets, buyers may therefore use search terms such as 1.4828 Stainless Steel Plate, DIN 1.4828 Plate, or 1.4828 SS Plates.

This makes 1.4828 an important keyword variation when researching or sourcing 309 Stainless Steel Plates internationally.

SS 309, 309S and 309H Grades

Stainless Steel 309 is available in related grades such as 309S and 309H. These grades are selected according to the required carbon level, temperature service, fabrication requirements, and applicable material specification.

SS 309

Standard SS 309 offers a combination of high-temperature strength, oxidation resistance, and corrosion resistance. It is widely used for industrial components exposed to elevated temperatures.

SS 309S

SS 309S Plates are the lower-carbon version of Type 309. The reduced carbon content can be beneficial for certain fabrication and welding applications.

SS 309H

SS 309H is a higher-carbon version intended for elevated-temperature applications where the required mechanical properties at high temperature are important.

SS 309 Chemical Composition

The chemical composition of Stainless Steel 309 is a major reason for its performance in high-temperature environments. Chromium provides corrosion and oxidation resistance, while nickel contributes to the stability of the austenitic structure.

Element	Typical Role / Requirement
Chromium (Cr)	Provides corrosion and oxidation resistance
Nickel (Ni)	Supports austenitic structure and high-temperature performance
Carbon (C)	Controlled according to the applicable 309 grade
Manganese (Mn)	Supports strength and manufacturing characteristics
Silicon (Si)	Contributes to oxidation resistance and processing properties
Phosphorus (P)	Controlled as specified by the applicable standard
Sulfur (S)	Controlled as specified by the applicable standard

The exact chemical composition should always be confirmed against the applicable material standard and the manufacturer's material test certificate rather than relying only on generic grade information.

SS 309 Mechanical Properties

SS 309 Plate mechanical properties are important when selecting material for structural, fabrication, pressure-related, and high-temperature applications.

Property	SS 309 Performance
Tensile Strength	High strength for demanding industrial applications
Yield Strength	Suitable for engineered structural and fabrication requirements
Elongation	Good ductility associated with austenitic stainless steel
Hardness	Controlled according to applicable specification and condition
High-Temperature Resistance	Excellent resistance to oxidation and elevated-temperature service

Exact minimum mechanical values depend on the applicable specification, product form, thickness, heat treatment, and delivery condition. For critical applications, the certified test values should be verified before purchase.

SS 309 Plate Dimensions

Stainless Steel 309 Plates can be supplied in standard and customized dimensions. Thickness, width, and length are generally selected according to the application and manufacturing requirements.

Specification	Available Requirement
Thickness	Standard and custom thicknesses
Width	Standard and cut-to-size widths
Length	Standard and customized lengths
Form	Plate, sheet, strip and cut-to-size plate

Custom SS 309 Plate dimensions can be requested when standard stock sizes do not match the fabrication or project requirement.

SS 309 Plate Surface Finishes

Surface finish is another important part of the specification when purchasing 309 Stainless Steel Plates. The required finish depends on whether the material is intended for fabrication, industrial equipment, architectural use, or further processing.

Hot Rolled Finish
Cold Rolled Finish
2B Finish
2D Finish
BA Finish
Pickled and Annealed Finish
Polished Finish
Custom Surface Finish

SS 309 Plate Manufacturing Forms

Depending on the supplier and project requirement, Stainless Steel 309 can be supplied in different forms and sizes.

Plain Stainless Steel 309 Plates
Hot Rolled SS 309 Plates
Cold Rolled SS 309 Sheets
SS 309 Strips
Cut-to-Size SS 309 Plates
Custom Fabricated Plates

Testing and Certification for SS 309 Plates

For industrial and engineering applications, buyers may require testing and documentation along with the material. Depending on the project specification, documentation can include a Material Test Certificate (MTC) showing chemical composition and mechanical test results.

Additional inspection and testing requirements may include dimensional inspection, visual inspection, hardness testing, positive material identification, and other tests specified by the purchase order.

Applications of ASTM A240 SS 309 Plates

The combination of high-temperature resistance, oxidation resistance, corrosion resistance, and mechanical strength makes SS 309 Plates suitable for many demanding applications.

Furnace components
Furnace linings
Oven linings
Firebox components
Boiler equipment
Heat exchangers
Heat treatment equipment
Kiln components
Petrochemical equipment
Power generation equipment
Chemical processing equipment
High-temperature containers
Industrial fabrication

Why Choose Stainless Steel 309 Plates?

Stainless Steel 309 Plates are selected when ordinary stainless steel grades may not provide the required performance at elevated temperatures. Their chromium and nickel content provides excellent resistance to oxidation and good corrosion resistance while maintaining useful mechanical strength.

For high-temperature industrial equipment, 309 Stainless Steel Plate can provide a practical combination of durability, heat resistance, fabricability, and corrosion resistance.

SS 309 vs 309S vs 309H

Grade	UNS Designation	Main Characteristic
SS 309	UNS S30900	General high-temperature stainless steel grade
SS 309S	UNS S30908	Lower-carbon version with improved welding suitability
SS 309H	UNS S30909	Higher-carbon grade for elevated-temperature service

How to Specify Stainless Steel 309 Plates

When requesting a quotation for SS 309 Plates, providing complete technical information helps ensure that the correct material is supplied.

Material grade – Stainless Steel 309
Standard – ASTM A240 / ASME SA240 where applicable
UNS designation – UNS S30900 where applicable
Thickness
Width
Length
Surface finish
Quantity
Testing and certification requirements
Cut-to-size or customized dimensions, if required

Stainless Steel 309 Plates for Industrial Applications

Choosing the correct Stainless Steel 309 Plate requires more than simply selecting the grade number. The applicable ASTM or ASME specification, UNS designation, dimensions, finish, manufacturing condition, testing requirements, and intended application should all be considered.

ASTM A240 SS 309 Plates remain a widely specified material for high-temperature industrial applications where resistance to oxidation, heat, and corrosion is required.

Conclusion

Stainless Steel 309 Plates are engineered for demanding applications where high-temperature performance and oxidation resistance are important. ASTM A240 provides a key specification for stainless steel plate, sheet, and strip, while ASME SA240 may be specified for applicable pressure vessel and code-related applications.

When sourcing SS 309 Plates, buyers should confirm the material grade, ASTM or ASME standard, UNS designation, dimensions, surface finish, testing requirements, and certification. Depending on the market, the material may also be identified as UNS S30900, AISI 309, or 1.4828 stainless steel.

For complete product information, available sizes, specifications, finishes, and supply options, visit the main Stainless Steel 309 Plates product page.