Stainless Steel- 410
Introduction: Grade 410 steel is martensitic steels which contain 11.5% of chromium, giving it moderate corrosion resistance properties which are enhanced by its heat treatment. This can make it firm with great resistance and strength. Since it is martensitic, it is more resistant to corrosion compared to austenitic grades which do not use the heat treatment.
Key Properties: The metal is high in strength and hardness. It is magnetic when it is annealed or hardened. It also consists of a high carbon content which makes it excellent in wear resistance and edge retention after hardening due to the formation of chromium carbide compounds. This grade is also equipped with high-temperature oxidation and scaling resistance. It is pocket-friendly due to the low alloy content along with great thermal conductivity.
Composition: The 410 stainless steel is composed of Carbon, Manganese, Silicon, Phosphorus, Sulphur, Nickel and the most important for 410, Chromium. Their percentage pertaining to the metal are as follows- 0.15%, 1%, 1%, 0.04%, 0.03%, 0.75% and between 11.5% and 13.5% respectively. The balance is completed by Iron.
Mechanical Properties: When the metal is annealed, it attains the minimum tensile strength of 65000 (psi) and also its yield strength minimum 2% offset is of 30000 (psi). It can be elongated 20% in 2 inches, and the hardness falls under Rockwell B80.
When the metal is hardened, the properties change. The tensile strength increases to 205000 (psi) and its yield offset also boosts up to 185000 (psi). It can be elongated by 8% in 2 inches, and the hardness falls under Rockwell C40.
Physical Properties: It has a melting point of 2729°F/1495°C with a density of 7.65 g/cm3. The specific gravity of this grade is 7.65, and the modulus of elasticity is 200 GPa. Its mean coefficient of Thermal Expansion ranges between 9.9-11.5°C depending on the temperature. Its Thermal Conductivity is 24.9W at 100°C and 28.7W at 500°C. Its electrical resistivity is 570nΩ.m.
Grade Specification Comparison: The UNS No. of the grade is S41000. In Old British specification, the BS number is 410S21, and the En number is 56A. The Euronorm name of the 410 stainless steel is X12Cr13 with the number 1.4006. The Swedish SS is 2302, and the Japanese SS is SUS410.
Possible Alternative Grades: The best alternatives to 410 will be grade 416, 420 and 440C. 416 can be used in places where high machinability is required, but a compromise on the corrosion resistance can be tolerated. 420 can be accepted where greater hardness is required than that of 410. If the hardness of grade 420 is also not acceptable, then 440C is the best option for having the best-hardened strength.
Corrosion Resistance: This grade of stainless steel has good resistance to air, water, hot gases, steam, mild acids and is satisfactory to other chemicals like ammonia, nitric acid, concentrated sulphuric acid, naptha and dilute acetic acid. Towards food acids, the corrosion resistance is much better. When it is hardened to its maximum, the resistance is also at its maximum. It is less corrosion resistant than austenitic grades and ferritic grades with higher chromium content like 430. For the best performance, in this case, a good finish gives the best results.
Heat Resistance: The mechanical properties of grade 410 reduces at temperatures ranging between 400°C and 580°C. Good scaling resistance can be achieved at temperatures as high as 650°C.
Heat Treatment: Grade 410 can be completely annealed between the temperatures 815°C and 900°C. This is to be followed by slow furnace cooling and air cooling.
For the process of hardening, the right temperature ranges between 925°C and 1010°C. This is followed by air cooling and oil quenching. This is followed by tempering to enhance the existing hardness of the metal. This process is conducted from 400°C to 580°C.
Welding: This metal is easy to weld. It should be heated up at 150°C to 260°C. After welding, grade 410 stainless steel should be annealed to avoid cracking. The welding rods can also be on the same grade but to achieve more ductility at the joint, 309 rods are recommended by AS 1554.6 standards.
Machining: When the metal is highly tempered or annealed, it reaches high machinability as it can be difficult to machine grade 410 metal if they are hardened above 30HRC. Therefore, 416 is often a better option compared to 410 in this context. Passivation and Decontamination after machining is highly recommended for grade 410 stainless steel.
Applications: The applications of grade 410 stainless steel are as follows:
- It can be used in pump shafts, valve components and gas and steam turbine components.
- It is also intricate surgical and dental instruments.
- Many automobile companies utilise it in automobile parts.
- It is also used for making cutlery, gate valves and press plates.
- Petroleum Refining industries, Ore and Sugar industries use it for equipment used for processing.