Cleaning of 304H Stainless Steel

Despite their corrosion resistance, stainless steel need care in fabrication and use to maintain their surface appearance even under normal conditions of service. In welding, inert gas processes are used. Scale or slag that forms from welding processes is removed with a stainless steel wire brush. Normal carbon steel wire brushes will leave carbon steel particles in the surface which will eventually produce surface rusting. For more severe applications, welded areas should be treated with a descaling solution such as a mixture of nitric acid and hydrofluoric acid, and these should be subsequently washed off.

For material exposed inland, light industrial, or milder service, minimum maintenance is required. Only sheltered areas need occasional washing with a stream of pressurized water. In heavy industrial areas, frequent washing is advisable to remove dirt deposits which might eventually cause corrosion and impair the surface appearance of the stainless steel.

Stubborn spots and deposits like burned-on food can be removed by scrubbing with a non-abrasive cleaner and fiber brush, a sponge, or pad of stainless steel wool. The stainless steel wool will leave a permanent mark on smooth stainless steel surfaces.

Many of these uses of stainless steel involve cleaning or sterilizing on a regular basis. Equipment is cleaned with specially designed caustic soda, organic solvent, or acid solutions such as phosphoric acid or sulfamic acid (strongly reducing acids such as hydrofluoric or hydrochloric may be harmful to these stainless steels). Cleaning solutions need to be drained and stainless steel surface rinsed thoroughly with fresh water. Design can aid cleanability. Equipment with rounded corners, fillets, and absence of crevice facilitates cleaning as do smooth ground welds and polished surface.