Is 1.4404 stainless steel magnetic?

Magnetic analysis of 1.4404 stainless steel (316L): a comprehensive analysis from composition to application

1. Basic properties of 1.4404 stainless steel
1.4404 is a stainless steel grade in the European Union standard (EN), corresponding to 316L in the American ASTM standard, and is an austenitic stainless steel (carbon content ≤ 0.03%, main components are Fe-16Cr-10Ni-2Mo). Its core characteristics are low carbon and high corrosion resistance, and it is widely used in medical equipment, food processing, marine engineering and other scenes with extremely high corrosion resistance requirements.

2.. Magnetic law of austenitic stainless steel
The magnetism of stainless steel mainly depends on the crystal structure:
Austenitic stainless steel (such as 316, 316L, 304, 304L):
Under annealing (unprocessed): The crystal structure is face-centered cubic (FCC) austenite, non-magnetic or only very weakly magnetic (extremely weak residual magnetism may remain due to impurities or processing).
After cold processing (such as stretching, bending, rolling): part of the austenite will transform into a body-centered cubic (BCC) martensite phase, resulting in weak magnetism in the material (the strength of the magnetism is positively correlated with the amount of processing deformation).
3. Is 1.4404 (316L) magnetic?
Conventional annealed 1.4404 stainless steel: no obvious magnetism, when adsorbed with ordinary magnets (such as NdFeB magnets), there is basically no attraction. 1.4404 stainless steel after cold processing or deformation: may produce weak magnetism (can be slightly adsorbed by strong magnets), but the magnetism is much weaker than ferrite/martensitic stainless steel.

4: Procurement advice: How to avoid the magnetic risk of 316L stainless steel?
Clarify technical requirements:
Indicate "annealed state, magnetic permeability μ≤1.02μ₀" in the procurement contract, and require the supplier to provide a material report (including magnetic test data).
Choose regular processing technology:
For parts that need to remain non-magnetic, hot processing (such as hot rolling, hot forming) or post-processing annealing is preferred to avoid magnetic risks caused by cold processing.
Sampling inspection:
After arrival, use a strong magnet for preliminary screening (no adsorption or only slight adsorption is qualified), and entrust a third-party testing agency to conduct magnetic permeability testing if necessary.