ASTM A270 sanitary tube (hygienic) are stainless steel tubing. ASTM A270 Tube standard specification for the welded seamless, and heavily cold worked welded austenitic and ferritic stainless steel sanitary tubing. It includes the stainless steel tube types in seamless and welded ERW, EFW. ASTM A270 sanitary tubing intended applied in the diary and food industry, bio processing equipment, and having special surface finish.
ASTM A270 / A270M - 15
An ASTM designation number identifies a unique version of an ASTM standard.
Standard Specification for Seamless and Welded Austenitic and Ferritic/Austenitic Stainless Steel Sanitary Tubing
Sanitary stainless steel tube A270 are mainly used in production equipment and assembly lines for food, beverage, alcohol, bioengineering, etc.
Mainly for the surface finish of stainless steel pipes, oil ban and passivation layer requirements;
1. Surface finish: Polishing the inner and outer surfaces of the steel pipe makes the surface of the steel pipe bright; that is, the mirror surface we often say. The main purpose is to prevent the fluid material in the tube from forming a wall in the tube, which is prone to pollution and form a tube blockage.
2. Passivation layer: After polishing, the steel pipe should be placed in a passivation tank for immersion, and the surface of the steel pipe is oxidized with an acid passivation solution to form a passivation layer to achieve the corrosion resistance of the steel pipe.
3. Oil-free degree: After the passivation is completed, the oil-free cleaning is carried out to remove the oil stain on the surface of the steel pipe. After completion, it needs to be tested with a grease analyzer. It mainly prevents the oil of the pipe wall itself from contaminating the fluid material flowing inside the pipe.
ASTM A270 Sanitary stainless steel tubing specification
ASTM A270 sanitary (hygienic) stainless steel tubing is the standard specification for the welded seamless, and heavily cold worked welded austenitic and ferritic stainless steel sanitary tubing. It includes the stainless steel tube types in seamless and welded ERW, EFW. ASTM A270 sanitary tubing intended applied in the diary and food industry, bio processing equipment, and having special surface finish.
View here for about information about ASTM A270 Standard Specification.
ASTM A270 stainless steel tube size range
ASTM A270 sanitary stainless pipe usually refers to the small pipe diameters, normally from 1/2” to 2 1/2”, thickness from 0.049 in (1.24mm) to 0.15 in (3.81mm).
The maximum outer diameter of ASTM A270 tubing is 12 inches (304.8 mm).
ASTM A270 tubing using inch-pound as the standard unit of measure.
Wall thickness tolerance shall not vary more than 12.5%.
Referred standard for ASTM A270 sanitary tubing
ASTM A 262: Methods of detecting intergranular corrosion for the magnetization coefficient.
ASTM A 480/A 480 M is the general specifications for flat stainless steel, heat-resistant stainless steel plate, sheet and steel bars.
ASTM A 923 Test methods for detecting detrimental intermetallic phase in duplex austenitic/ferritic stainless steels
ASTM A 967 is the specification of passivation treatment for stainless parts .
ASTM A 1016/1016 M is the general specification for ferritic alloy steel, austenitic alloy steel and stainless steel.
E 527 is the test methods for numbering metal and alloy
ASTM B 46.1 surface structure (surface roughness, waviness and layers).
ASME boiler and pressure vessel’s numbers and other standards.
Stainless tube manufacturing processes
ASTM A270 sanitary stainless steel pipe shall be noted below points during manufacturing processes:
1) Seamless steel pipe should not contains any kind of welding processing.
2) Welded steel pipe applied in automatic welding processing, but should not use metal materials as filler.
3) Heavily cold worked (HCW) tubes shall be manufactured by cold working of not less than 35% reduction of thickness of both wall and weld to a welded pipe prior to the final anneal. Filler materials shall be noted added during welding process. The weld shall be 100% radio graphically inspected in accordance with ASME boiler and pressure vessel standards specification.
4) Sanitary pipe could be furnished with hot finished or cold finished at Manufacture’s option.
Hot-treatment methods for ASTM A270 stainless tube
All materials should supply after hot-treatment. Except the for duplex stainless steel materials S31803, S32003, S320205, S32750, N08926 and N08367, in these cases it shall consist of heating the material to a minimum temperature of 1900 ℉ (1040 ℃) and quenching in water or rapid cooling by other means.