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Similar appearance, different steel families
An appliance panel and a process tank may have similar stainless surfaces without using the same steel. Grade 430 belongs to the ferritic family, while 304 is austenitic. These names describe the internal structure of the metal. Differences in composition affect not only corrosion resistance but also magnetic response and dimensional change with temperature.
Grade 430 / 1.4016 relies mainly on chromium for its stainless character. Grade 304 / 1.4301 also contains substantial nickel, which supports the austenitic structure. This distinction does not make either steel universally superior. It explains why different properties become useful in everyday applications.
What does a magnet test show?
Grade 430 is strongly attracted to a magnet because of its ferritic structure. Stainless steel does not have to be non-magnetic. Attraction to a kitchen or cladding component therefore does not, by itself, show that the material is not stainless or that it is poor quality.
The magnetic response of 304 is generally very low in its soft condition, but some deformed regions can become more magnetic. A magnet gives a clue about the family rather than a complete grade identification. It cannot reliably distinguish every visually similar component as 430, 304 or another stainless steel.
Corrosion resistance and surroundings
Grade 430 is common indoors and in relatively mild corrosive conditions. Appliance cladding, kitchen-equipment bodies and decorative components are examples. Appearance, cleanability and resistance to ordinary moisture all matter in these parts.
Grade 304 has a broader corrosion-service range and is common in tanks, equipment bodies and industrial systems. Salt water and concentrated chlorides nevertheless remain more demanding for 304 too. Molybdenum-bearing 316L and more highly alloyed stainless steels have distinct roles. Surface brightness alone does not reveal these differences.
Cladding, equipment bodies and temperature changes
Ferritic 430 generally expands less with temperature than austenitic 304. This can matter in broad metal panels and equipment components near heat. Grade 304 is known for its formability and use in a wide variety of geometries. A broad panel and a deep vessel can therefore benefit from different properties despite a similar stainless appearance.
Grade 434 / 1.4113 is another option within the ferritic family. Molybdenum improves resistance in some environments compared with 430, but it does not make 434 another name for 304. Applications, corrosion behaviour, magnetic response and physical properties together explain the relationship between these grades.