ASTM A270 Standard Core Content
Scope of application
The ASTM A270 standard is developed by the American Society for Testing and Materials (ASTM International). The standard is applied to a number of industries that have extremely high requirements for cleanliness, hygiene standards, and material surface quality, including the food processing industry, pharmaceutical industry, bioengineering field, chemical industry, and health and environmental protection fields, etc.
Key requirements
Surface roughness: Surface roughness is a crucial indicator in the ASTM A270 standard, which affects the cleanliness of the steel pipe. The Ra value (arithmetic mean roughness of the surface) is used as the main measurement standard. The Ra value is usually required to be no more than 35 microinches (0.89 microns). This requirement ensures the smoothness of the steel pipe, reduces the residue attached to the steel pipe, and effectively resists pollution and bacteria.
Dimensional tolerance: This is an important factor to ensure whether the steel pipe can match during installation and use. When the wall thickness is ≥0.049 inches (1.24 mm), the outer diameter deviation must strictly comply with the standard limit, but for steel pipes with a wall thickness of <0.049 inches, the outer diameter deviation is not required. It can be negotiated with the purchaser to meet specific needs
Material requirements: This standard has clear requirements for the selection and performance of materials, specifically austenitic stainless steel (304 stainless steel, 304 stainless steel), duplex stainless steel (ferrite/austenite composite structure material).
Comparative Analysis of ASTM A270 and A269
|
Comparison Items |
ASTM A270 |
ASTM A269 |
|
Surface requirements |
Clarify Ra value specifications and emphasize surface finish |
No mandatory roughness requirement, focusing on mechanical properties |
|
Size Range |
OD ≤ 12 inches, focus on thin-walled tubes |
Inner diameter ≥ 1/4 inch, wall thickness ≥ 0.020 inch |
|
Mechanical properties |
Not mandatory (health use is preferred) |
Need to meet indicators such as tensile strength and yield strength |
|
Applicable Materials |
Austenitic, ferrite/austenitic duplex stainless steel |
Mainly austenitic stainless steel such as 304 and 316 |
Selection suggestions
A270 applicable scenarios
ASTM A270 standard is mainly used in environments with sanitary surface quality and easy cleanability requirements.
1. Dairy processing
Specific equipment: widely used in milk tanks, pipelines, pasteurization equipment, etc.
2. Pharmaceutical industry
Specific equipment: including liquid medicine pipelines, fermentation tanks, sterilization equipment, etc.
3. Bioengineering and laboratories
Specific equipment: used for culture medium pipelines, reactors, purification equipment, etc.
A269 applicable scenarios
Applicable to ordinary industrial pipelines, taking into account corrosion resistance and mechanical strength conditions.
1. Chemical equipment
Specific equipment: including reactors, towers, pipelines, storage tanks, etc.
2. Heat exchangers
Specific equipment: widely used in plate heat exchangers, shell and tube heat exchangers, etc.
3. Oil and gas industry
Specific equipment: including oil pipelines, natural gas pipelines, drilling equipment, etc.
Summary
ASTM A270 and A269 are two important standards for stainless steel pipes. The ASTM A270 standard is mainly aimed at the high requirements in the sanitary field. In contrast, ASTM A269 focuses more on the general performance of stainless steel pipes. ASTM A270 and A269 have their own focuses. In practical applications, the choice of which standard needs to be weighed according to specific needs.
