Grade 410 stainless steels are general-purpose martensitic stainless steels containing 11.5% chromium, which provide good corrosion resistance properties. However, the corrosion resistance of grade 410 steels can be further enhanced by a series of processes such as hardening, tempering and polishing. Quenching and tempering can harden grade 410 steels. They are generally used for applications involving mild corrosion, heat resistance and high strength.
Martensitic stainless steels are fabricated using techniques that require final heat treatment. These grades are less resistant to corrosion when compared to that of austenitic grades. Their operating temperatures are often affected by their loss of strength at high temperatures, due to over-tempering and loss of ductility at sub-zero temperatures.
The properties displayed below are applicable to bar products of ASTM A276. Other products such as forgings, wire and plate may not have similar properties.
Grade 410 stainless steels are resistant to hot gases, steam, food, mild acids and alkalies, fresh water and dry air. These steels obtain maximum corrosion and heat resistance through hardening. However, grade 410 steels are less corrosion resistant than austenitic grades and grade 430 ferritic alloys containing 17% chromium. Smooth surface finish offers improved performance of steels.
Grade 410 steels have good scaling resistance at temperatures of up to 650 °C. However, the mechanical properties of the material will tend to reduce at temperatures ranging from 400 to 580 °C.
Annealing - Grade 410 steels can be fully annealed at temperatures from 815 to 900 °C, followed by slow furnace cooling and air-cooling. Process annealing of grade 410 steels can be carried out at temperatures ranging from 650 to 760 °C and air-cooled.
Hardening – Hardening of grade 410 steels can be performed at 925 to 1010 °C, followed by air and oil quenching. Heavy sections of grade 410 need to be oil quenched. Tempering, to enhance the mechanical properties and hardness of grade 410 steels, follows this process. It is not recommended to perform tempering at temperatures from 400 to 580 °C.
Grade 410 steels can be welded using all conventional welding techniques, but the materials should pre-heated at 150 to 260 °C followed by post-weld annealing treatment, to mitigate cracking. Grade 410 welding rods are recommended for tempering and post-hardening. In the "as welded" conditions, grade 309 filler rods can be used to achieve a ductile joint.
According to AS 1554.6 standards, grade 309 electrodes or rods are preferred for welding 410 steels.
Grade 410 steels can be easily machined in highly tempered or annealed conditions. However, it is hard to machine grade 410 steels if they are hardened above 30HRC. Free machining grade 416 is the best alternative.
Grade 410 stainless steels find applications in the following:
Bolts, screws, bushings and nuts
Petroleum fractionating structures
Shafts, pumps and valves
Mine ladder rungs