JIS G 3463-1994 defines the chemical composition requirements for stainless steel tubes used in boilers and heat exchangers. The standard prohibits the use of titanium and other titanium-containing alloys in tubes intended for use in a pressure vessel.
This standard specifies that the chemical composition of the stainless steel tubes shall not exceed the maximum limits as indicated below:
Carbon 0.08%
Sulfur 0.03%
Silicon 0.15%
Manganese 2.00%
Nickel 10.00%
Chromium 16.00%
Molybdenum 2.00%
The carbon content should not exceed 0.08%. This is because excessive carbon can adversely affect the material’s heat-resisting properties and accelerate corrosion.
The maximum amount of sulfur allowed in the stainless steel tubes is 0.03%. Excessive amounts of sulfur can lead to scaling and corrosion.
The maximum amount of silicon allowed in the stainless steel tubes is 0.15%. Silicon can have an adverse effect on the material’s ductility and tensile properties.
The maximum amount of manganese allowed in the stainless steel tubes is 2.00%. Excessive amounts of manganese can lend a brittleness to the material and can decrease corrosion and heat resistance.
The maximum amount of nickel allowed in the stainless steel tubes is 10.00%. Excessive amounts of nickel can reduce machinability and lead to build up of strain, which can cause structural problems.
The maximum amount of chromium allowed in the stainless steel tubes is 16.00%. Excessive amounts of chromium can reduce the material’s weldability.
The maximum amount of molybdenum allowed in the stainless steel tubes is 2.00%. Excessive amounts of molybdenum can lead to embrittlement of the material and reduce its corrosion resistance.
In conclusion, JIS G 3463-1994 sets out the chemical composition requirements for stainless steel tubes used in boilers and heat exchangers. It specifies limits on the maximum amount of carbon, sulfur, silicon, manganese, nickel, chromium, and molybdenum that may be present in stainless steel tubes intended for use in a pressure vessel. Excessive amounts of these elements can reduce the material’s performance and reliability.
