Stainless steel is an alloy which contains iron, chrome, carbon and other elements, mainly nickel, molybden, manganese, silicone and titanium, etc., which lends them a certain resistance to some types of corrosion. Naturally, the influence of various elements produces distinct variations in the intrinsic characteristics of the diverse types of metal. Regulation EN 10088 defines stainless steel as any iron-based alloy with a minimum of 10.5% of chrome.
The main component of the alloy must be iron. The reason for this definition is in the characteristics of these alloys to effectively resist a corrosive attack, a property which was shown in experiments by Tamman. The results of these experiments reflect how the percentage of chrome in alloy determines the minimum rate of weight loss in a corrosive environment.
Resistance to corrosion is due to the property of these alloys to become passive in an oxidising environment (e.g. the air) through the formation of a superficial film of absorbed oxygen. These conditions are referred to as stainless steel in a “passive” state.
The passive film reforms when damaged if the atmosphere is sufficiently oxidising and oxygen enters into contact with the alloy. This film protects the underlying material from the corrosive attack.
ROS DUCTING, S.L.U. and KMH manufacture parts in AISI 304 stainless steel while products in AISI 316 steel can be made to order.