It is generally preferred that the electrical enclosures are manufactured from stainless steel material. Stainless steel enclosure are used in various industrial applications where corrosion resistance is important. However, there are rules to be considered when selecting and using stainless steel materials.
Grinding is common surface treatment for stainless steel enclosures used in industrial applications. The protective film as the purpose of masking, adhered on the outer surfaces of the enclosures is kept to the very last of the manufacturing steps, after removing the film and the possible adhesive residues are cleaned with special chemicals, the enclosure is packed with an air-permeable material before last packaging.
In addition to the surface treatment quality, the direction of grinding of the stainless steel surface is also important in terms of corrosion resistance. The vertically oriented grinding allows cleaning to be done easily and in case of outdoor applications, rain water can flow down itself with help of gravity. Some stainless steel enclosures can be painted. Especially, it is known that outdoor stainless steel enclosures exposed to intense solar radiation can be 10 degrees cooler, if they are painted with a light color. It is also possible to consider the paint as an additional layer of protection for extremely corrosive environments. Stainless steel can be painted by using standard paint process.
Stainless steel enclosure s are also preferred for their superior hygienic features in addition to their corrosion resistance. It is more difficult to stick and reproduce for bacterias and microbes on stainless steel surfaces (assuming to have appropriate surface smoothness). The smooth and though surface of the stainless steel allows for easier and more effective cleaning.
Precautions for storage and construction site environment
In order to ensure that the surface qualities of stainless steel enclosures are also protected under storage and site conditions, some precautions might be needed to be taken in addition to the manufacturer’s precautions such as product packaging.
Water which may accumulate during storage and transport, especially under heat shrinkage or under the plastic packaging of the stretch-film construction, may cause corrosion. This is the case when the packaged product is left in a humid environment for a long time. Strong acids (chloride based) which can be used for cleaning after ground work, especially stone or ceramic laying in new buildings, should be prevented from getting in contact with stainless steel surfaces. Any cleaning or rinsing fluid must not be interacted with the surrounding metals.
During storage, transfer, positioning and assembling in construction site environment, contamination of stainless steel enclosures’ surfaces with carbon steel or iron must be avoided. For example, metal machining, grinding or welding around stainless steel enclosures should be avoided or precautions should be taken. Carbon steel metal burrs or slag splashing on the stainless steel surfaces will cause corrosion of splinters.
Cleaning before delivery
The stainless steel electrical enclosures manufactured by EAE, are delivered in an air-permeable package material, after the protective film is stripped and the surface is cleaned with flying chemicals which have protective features for stainless steel. Before the final delivery against the contamination, it is necessary to clean the surface defections which may be occurred in the workshop environment or the construction site environment. Mortars and cement particles can be cleaned with 10-15% phosphoric acid. The solution should be applied hot onto the surface, subsequently, neutralized by the ammonia solution, finally rinsed with water purified from the minerals. Cleaning products manufacturers offer some special products for this type of cleaning. The superficial light stains can be removed by gentle cleaning creams and polishing pastes which are available in the market. These cleaning products contain substances that can penetrate
the surface together with calcium carbonate. Household cleaners are also based on lemon acid and suitable for cleaning.
Grinding powders containing iron adhering to the surface in a short time ago, should be cleaned with saturated solutions of oxalic acids. Firstly, it must be applied to the surface without pressing hardly with a soft cotton cloth or cotton-based polishing pad and waited for a few minutes. Thus, as a rule, it is ensured that the particles are separated from the surface without scratches and damages on the surface. Moderate level rust stains are cleaned using cleaning products containing phosphoric acid. Careful cleaning is done without damaging the surface and changing color. Alternatively, small amounts of iron particles treated on the surface are successfully cleaned with slenderized nitric acid. It is only possible to clean the surface treated with rust thoroughly with acid processing and / or passivation to be done professionally. The acid cleaning process should be considered as a thin layer removal from the surface. For this, a mixture of nitric acid and hydrofluoric acid is generally used. Passivation process is a controlled and accelerated reconstitution of the impaired passive layer on the surface in the nitric acid environment. However, first of all, the oil and organic soils on the surface must be cleaned.
For all stainless steel applications, periodic surface maintenance should be planned and applied during operation.
304 and 316 grades raw material discrimination test:
A fine liquid from Monil 304-316 separator solution is dropped on the surface (under room temperature). 20-25 minutes to be waited. The colour of drop is
watched. On the tested surface, in 5 minutes, yellowgreen- brown color changes in sequence as the proof of 316 grade stainless steel. For 316L grade stainless
steel, more than 5 minutes to be waited.