304, 304H and 304L all possess the same nominal chromium and nickel content and thus possess the same corrosion resistance, ease of fabrication and weldability. The difference between 304, 304H and 304L is the carbon content which is >0.03, >0.05 and <0.03 respectively.The carbon content of 304H (UNS S30409) is restricted to 0.04–0.10%, which provides optimal high temperature strength.

TP 316Ti (1.4571, UNS S31635) is generally considered but is not resistant to hot sea water. Hot chloride environments may cause pitting and crevice corrosion. TP 316Ti (1.4571, UNS S31635) HEAT RESISTANCE 316 exhibits good resistance to oxidation in continuous service to a temperature of 870 ° C and a temperature of 925 ° C. However, if corrosion resistance to water is required, continuous use at 425-860 ° C is not recommended. In this case, 316L is recommended due to resistance to carbide precipitation. When high temperatures are required at temperatures above 500 ° C, class 316H is recommended.

Grades 321 and 347 are the basic austenitic 18/8 steel (Grade 304) stabilized by Titanium (321) or Niobium (347) additions. These grades are used because they are not sensitive to intergranular corrosion after heating within the carbide precipitation range of 425-850°C. Grade 321 is the grade of choice for applications in the temperature range of up to about 900°C, combining high strength, resistance to scaling and phase stability with resistance to subsequent aqueous corrosion.

The yield strength is more than twice that of ordinary austenitic stainless steel, and it has the necessary requirements for forming Sufficient plasticity. The wall thickness of storage tanks or pressure vessels made of duplex stainless steel is 30-50% less than that of beneficial to reduce costs.

310/310S find wide application in all high-temperature environments where scaling and corrosion resistance, as well as high temperature strength and good creep resistance are required.

904L is an austenitic stainless steel. Though notably softer than 316L, its molybdenum addition gives it superior resistance to localized attack (pitting and crevice corrosion) by chlorides and greater resistance reducing acids and in particular its copper addition gives it useful corrosion resistance to all concentrations of sulphuric acid. Its high alloying content also gives it greater resistance to chloride stress corrosion cracking, but it is still susceptible. Its low carbon content makes it resistant to sensitization by welding and which prevents intergranular corrosion

Alloy 317L (UNS S31703) is a low carbon corrosion resistant austenitic chromium-nickel-molybdenum stainless steel. The high levels of these elements assure the alloy has superior chloride pitting and general corrosion resistance to the conventional 304/304L and 316/316L grades. The alloy provides improved resistance relative to 316L in strongly corrosive environments containing sulfurous media, chlorides, and other halides.

Alloy 800 - The 800 series of alloy (Incoloy 800, 800H and 800HT) are nickel-iron-chromium superalloys that have excellent properties of high temperature strength and resistance to oxidation, carburization and other types of high temperature corrosion. Alloy 800, 800H and 800HT are used in various applications from furnace components, petrochemical furnace cracker tubes to sheathing for electrical heating elements. Application: Chemical and petrochemical process piping, heat exchangers, furnace components, carburizing equipment, heating-element sheathing, and nuclear power steam-generator tubing.