Stainless steel is more corrosion and rusting resistant than low carbon steel. In steel, the iron surface is easily form a oxide film and tends to form more oxide. This cause the oxide diffuse inside the alloy so rusting can occurs readily. However, stainless steel contains plenty of chromium. The chromium can form a passivation (oxide film) and obstruct the diffusion of the oxygen from surface to the internal structure.
The importance of Silicon in Cast Iron. As mentioned before the amount of silicon in a cast iron can be rather difficult to control in the cupola furnace but relatively easy to control in induction melting. Silicon tends to increase the instability of the cementite so that this decomposes to graphite and hence the colour of grey cast iron. The higher the silicon content, the greater the degree of decomposition of the cementite, and the coarser the flakes of graphite produced. Therefore, although silicon is known to dissolve in the ferrite and strengthen it, it also softens the cast iron by increasing the graphite content and reducing the cementite content.
In 300 series for more corrosion resistance. 304 along with 304L series is the most used in the 300 series. In 316 type, 2% Cr replaces equivalent % of Mo for enhanced pitting corrosion. L, low carbon grades became popular with the advent of low cost melting process AOD, Argon Oxygen Decarburization. Austenitic steels are hypo eutectoid steels with carbon content less than eutectoid composition of 0.76%.
Aluminium metal is highly preferred for sacrificial anode mainly because of its high current capacity. However, pure aluminium is not useful as an anode because it immediately forms a passive oxide film on its surface when it is exposed to the environment. The development of an aluminium anode is always dependent upon the activation of aluminium by diminishing the detrimental effects of the oxide films. As well known alloying additions in aluminium exert great effects on its electrochemical performance, especially its potential, which is one of the most important characteristics for sacrificial anodes. In order to promote surface activation, aluminium is usually alloyed with small quantities of one or more of such elements as mercury, tin, indium, zinc, bismuth and magnesium which hinder or prevent the formation of surface films .
CARBON STEELS: They are the steel containing iron and carbon. Carbon steel contain main additive element as carbon which is in the range of 0.12 to 2%. It is soft, malleable and tough. PROPERTIES OF IRON: Iron is shiny bright white metal which is soft, strong, malleable and ductile having atomic number 26. Iron conduct heat and electricity.
Al is the principle alloying elements because it is one of the strongest α stabilizers. Al is a very effective alpha-strengthening element at ambient and elevated temperatures up to about 550 °C. The low density of aluminum is an additional advantageous feature but the amount that can be added is limited because of the formation of a brittle titanium aluminium compound, Ti3Al, at aluminum contents exceeding about 8wt. %. Sn also plays the role of α phase stabilizer to improve ductility [Singh et al.
Under the influence of oxygen from air or water, the chromium rapidly forms a very thin, chromium (III) rich oxide film on the surface of the steel.This layer very effectively separates the material from the surroundings.It is adherent, coherent and insoluble under normal conditions. Increasing the chromium content, from the minimum of 10.5% necessary for "stainless steel", to 17 to 20%, greatly increases the stability of the corrosion resistance film. . Stainless steels may contain up to 38% nickel as another major alloying element.The properties of stainless steels can be adjusted with several alloying elements in addition to chromium and nickel.These
Nickel has high specific energy but poor stability whereas manganese forms a spinel structure to achieve low internal resistance but has a low specific energy. Therefore, the metals enhance each other’s strengths. The composition of the cathode is usually one-third nickel, one-third manganese, one-third cobalt. This lowers the raw material cost as it reduces the amount of cobalt used. Other combinations also exist, such as NCM, CMN, CNM, MNC and MCN in which the metal content is different from the ‘one-third’ formula.
Also it is recommended in Cobalt- and Nickel-based alloys casting process where low-carbon and ultra-low-carbon steels also can be processed. You can ask the foundry filter supplier for customized sizes as per your requirement. It is easier to cast most of the high alloy and high carbon steels compared to plain carbon steels. Also, casting Austenitic Mn-Steels fails through ZrO2 filters for its low casting temperature feature. The filter capacity can be increased using vacuum melting and casting furnaces to its maximum.
Iron (Fe) is renowned for its strength and low price but it is very heavy in weight. To make use of it in scenarios that demand light weight without resorting to buying expensive stronger materials such as titanium (Ti), it is often alloyed with aluminum (Al) which is light and mercifully cheap. The mixture of iron and aluminum usually includes a sprinkling of manganese to make it less brittle. Brittle intermetallic compounds can form poor ductility alloys at room temperature which limit their usage as they are difficult to process into useful shapes such as plates and tubes . Using strengthening second phase control Fe–Al alloys can be effectively hardened by controlling aluminum morphology and dispersion in the iron based alloy .