When is a hose reel with a housing made of stainless steel AISI 316 recommended?
A housing made of stainless steel AISI 316 is recommended when the hose reel is regularly exposed to chloride-containing moisture, salty deposits, or corrosive process and cleaning media. Compared to AISI 304, AISI 316 offers higher resistance to chloride-induced pitting and crevice corrosion. Responsible for this is particularly the additional molybdenum content of about 23%. This improves the corrosion resistance under demanding environmental conditions.
For the hose reel, this results in the following specific areas of application:
Proximity to the coast, ports, and maritime work areas: In salty air and occasional contact with seawater splashes, AISI 316 offers higher corrosion resistance than AISI 304. Salt deposits should still be removed regularly, as chlorides can accumulate on the surface when the water evaporates.
Washing areas, vehicle cleaning, and municipal operations: If de-icing salt-laden spray water or corresponding residues reach the housing, the increased resistance to chloride-induced corrosion is a significant advantage. This is particularly relevant with repeated wetting and subsequent drying, which can concentrate salts. This application recommendation arises from the corrosion behaviour in chloride-containing moisture.
Food processing and hygienically demanding production areas: AISI 316 is particularly advantageous when salty products, brine, or corrosive cleaning agents come into contact with the housing. The decisive factor is the specific chemical exposure; belonging to the food or pharmaceutical industry alone does not make AISI 316 necessary.
Swimming pools and water treatment: With regularly cleaned housing surfaces, AISI 316 can offer higher resistance to discolouration, pitting, and crevice corrosion compared to AISI 304. However, suitability depends on water composition, disinfectants, and local conditions.
Chemical plants and laboratories: AISI 316 offers advantages over AISI 304 in certain acidic and chloride-containing media. The selection must be made based on the specific substance, its concentration, temperature, and duration of exposure. A general resistance to aggressive acids or alkalis cannot be derived from this.
When is AISI 316 technically required?
AISI 316 is required over AISI 304 when AISI 304 does not provide sufficient corrosion resistance under the intended operating and cleaning conditions, and the suitability of AISI 316 for these conditions has been demonstrated.
For typical indoor spaces and lightly stressed outdoor areas without significant salt or chemical exposure, AISI 304 is generally sufficient. For the selection of the housing, the external load, such as splashes, deposits, and cleaning, is important. The resistance of the hose, rotary union, and seals to the conveyed medium must be checked separately.
AISI 304 is usually assigned to the material 1.4301, AISI 316 to the material 1.4401.
