The A240 standard was established by the ASTM American Society of Testing Materials.
These standards generally deal with chromium stainless steel and chromium-nickel stainless steel plates, sheets, and strips.
These plates and sheets are used in numerous applications, mostly in pressure vessels.
This standard covers several grades of stainless steel and describes their mechanical properties and chemical composition when used in the form of sheets and plates.
Architecture, construction, and building are common applications for these stainless steel standards. The standard includes organized standards for sample methods and certification requirements.
This article discusses more about the chemical composition, grades, and mechanical properties of ASTM 240 stainless steel grades.
Grades
ASTM A240 steel plate standard includes all the stainless steel families, such as austenitic steels, ferritic steels, and martensitic steels. Some more commonly used steel grades, which play a very important role in the industry, are elaborated on in the given table.
Grades | Raw Material |
304 | Austenitic stainless steel 18% chromium, 8% nickel |
316L | Austenitic stainless steel chromium, nickel, molybdenum and low carbon |
321 | 18-8 chromium nickel Austenitic stainless steel stabilized with titanium |
410 | Martensitic stainless steel with 12% chromium |
904L | Super austenitic stainless steel with high nickel chromium composition |
UNS S31803 | Ferritic / Austenitic duplex stainless steel |
UNS S32750 | Ferritic / Austenitic super duplex stainless steel |
UNS S31254 | Austenitic stainless steel with high molybdenum |
Chemical Composition
The chemical composition of some more commonly used grades of ASTM A240 stainless steel standard is shown in the given table:
Grades | C % | Mn Max % | P Max % | S Max % | Si % | Cr % | Ni % | Mo % | N % | Cu % | Ti % |
304 | 0.07 | 2.0 | 0.045 | 0.03 | 0.75 | 17.5~ 19.5 | 8~ 10.5 | – | 0.1 Max | – | – |
304L | 0.03 | 2.0 | 0.045 | 0.03 | 0.75 | 17.5~ 19.5 | 8~12 | – | 0.1 | – | – |
316 | 0.08 | 2.0 | 0.45 | 0.03 | 0.75 | 16~18 | 10~14 | 2~3
| 0.1 Max | – | – |
316L | 0.030 | 2.0 | 0.45 | 0.03 | 0.75 | 16~18 | 10~14 | 2~3 | 0.1 | – | – |
321 | 0.08 | 2.0 | 0.45 | 0.03 | 0.75 | 17~19 | 9~12 | – | 0.1 Max | – | C+N 0.70 |
410 | 0.08~ 0.15 | 1.0 | 0.04 | 0.03 | 1.0 | 11.5~ 13.5 | 0.75 | – | – | – | – |
904L | 0.02 | 2.0 | 0.045 | 0.035 | 1.0 | 19~23 | 23~28 | 4~5 | 0.1 | 1~2 | – |
UNS S31803 | 0.03 | 2.0 | 0.030 | 0.020 | 1.0 | 21~23 | 4.5~ 6.5 | 2.5~ 3.5 | 0.08~0.2 | – | – |
UNS S32750 | 0.03 | 1.20 | 0.035 | 0.020 | 0.08 | 24~26 | 6~8 | 3~5 | 0.24~ 0.32 | 0.5 | – |
UNS S31254 | 0.02 | 1.0 | 0.030 | 0.010 | 0.80 | 19.5~ 20.5 | 17.5~18.5 | 6.0~ 6.5 | 0.18~ 0.25 | 0.5~ 1.0 | – |
Product Properties
Products in ASTM A240
Stainless steel plates
ASTM A240 specifies the standards for stainless steel plates, which are flat, rectangular slabs of stainless steel used in building, manufacturing, and industrial uses.
Stainless steel sheets
ASTM A240 also applies to stainless steel sheets, which are identical to plates but less in thickness. They are frequently utilized in industries such as automotive, aerospace, and the manufacture of kitchen appliances.
Stainless steel strips
Generally, strips are small, narrow, thin, and small pieces of stainless steel. ASTM A240 covers stainless steel strips of all austenitic, martensitic, and ferritic stainless steel grades.
Stainless steel strips are mostly used in précised applications like electronic devices and medical equipment.
Mechanical Properties
All the stainless steel grades of ASTM A240 standard have excellent corrosion resistance and mechanical strength; therefore, these grades show better mechanical properties. Mechanical properties of some commonly used grades are given below.
Grades | Tensile strength ksi min | Yield strength ksi min | Elongation min % | Hardness Max
|
304 | 75 | 30 | 40 | 92 HRB or 201 HBW |
316 | 75 | 30 | 40 | 95 HRB or 217 HBW |
321 | 75 | 30 | 40 | 95 HRB or 217 HBW |
410 | 65 | 30 | 20 | 96 HRB or 217 HBW |
904L | 71 | 31 | 35 | 95 HRB |
UNS S31803 | 90 | 65 | 25 | 31 HRC or 293 HBW |
UNS S32750 | 116 | 80 | 15 | 32 HRB or 310 HBW |
UNS S31254 | 100 | 45 | 35 | 96 HRB or 223 HBW |
Delivery State
All stainless steel plates, sheets, and strips must be provided in the solution treatment state, according to ASTM A240. This kind of treatment also increases the strength and toughness of the stainless steel. The solution-treated stainless steel sheets and plates have the longest service life during use.
Furthermore, most stainless steel sheets and plates require surface treatment after heat treatment, such as polishing or pickling. This removes the scale and unevenness that develops after heat treatment.
Other Information
Dimension
The plates, sheets, strips, and coils of ASTM A240 standards are available in a specific range of dimensions like thickness and width. ASTM A240 product dimensions are shown in the following table:
Product | Thickness (mm) | Width (mm) | Length (mm) |
Cold rolled coils(2D/2B/BA) | 0.3-3 | 800-1300 | Coil |
Hot rolled coils(No.1) | 2-10 | 800-2000 | Coil |
Plate | 3 – 150 | 1000 – 3000 | 2000-12000 |
Sheet | 0.4 – 6 | 1000 – 2000 | 2000-6000 |
Strip | 0.05 – 3 | 3 – 600 | Coil |
Hydrostatic Test
There is no hydrostatic testing required in ASTM A240 standard. It may relate to other standards or specifications that specify the testing procedures and acceptance criteria. For example, it is applicable in ASTM B622, which is related to pipes and tube grade standards.
Conclusion
The ASTM A240 is the most widely used standard for sheets, plates, strips, and coils of stainless steel.
Stainless steel is a versatile material used in several applications due to its outstanding properties like corrosion resistance, strength, toughness, and formability.
The products of this standard are mostly used in pressure vessels, food processing, chemical processing, the automotive industry, medical equipment, and the petrochemical industry.
We can produce stainless steel products in full compliance with ASTM A240. You can contact our team if you have any requirements.
