1.4301*, DIN X5CrNi1810, AISI 304

 1.4301*, DIN X5CrNi1810, AISI 304

Designation by Standards

 

Chemical Composition (in weight %)

Description
One of the most widely used and oldest of the stainless steels. This was originally called 18-8 which stood for its chromium and nickel content. It possesses an excellent combination of strength, corrosion resistance and fabricability.

Applications
The list is endless. Almost every conceivable industry uses some of this material in some way. Everything from stovetops to ball point pen barrels to flatware to fasteners has been fabricated from this alloy.

Physical properties (avarage values) at ambient temperature
Modulus of elasticity [10³ x N/mm²]: 200, 186 (200^oC), 172(400^oC)
Density [g/cm³]: 7.92
Thermal conductivity [W/m.K]: 15.0
Electric resistivity [Ohm mm²/m]: 0.73
Specific heat capacity[J/g.K]: 0.50

Coefficient of Linear Thermal Expansion 10^{-6 o}C^-1

Hardening
Harden from a temperature of 1000-1080^oC followed by water or air (sufficiently fast) quenching. Structure after quenching is austnite withn small ferrite component.

Mechanical properties in solution-annealed condition and reistance to intercrystalline corrosion
0.2 % proof stress: 190 N/mm² (for d<=160, 160<d<=250)
1.0 % proof stress: 190 N/mm² (for d<=160, 160<d<=250)
Tensile strength: 225 N/mm²( for d<=160, 160<d<=250)
Elongation: 45% (for d<=160, longit.), 35% (for 160<d<=250, transv.)
Notch impact energy (ISO-V): 100 J (for d<=160, longit.), 60 J (for 160<d<=250, transv.) Resistance to interystalline corrosion: yes (in as delivered condition), no (in sensitised condition)
Note: Sensitisation treatment for 15 min at 700^oC with subsequent cooling in air.

Mechanical Properties At Elevated Temperatures

Forging
Hot forming temperature: 1200-900^oC.

Machinability
Slow speeds and heavy feeds will minimize this alloys tendency to work harden. Due to long stringy chips, the use of chip breakers is advisable. Many companies now offer premium machinability grades, such as CarTech with their Project 70 and 7000 series.

Corrosion Resistance
Resistant to a wide range of environments between moderately reducing and slightly oxidizing. This covers food, fresh water, sterilizing solutions and dilute nitric and acetic acids.

Welding
All fusion and resistance processes have been successfully employed in welding 304. AWS E/ER308 or 312 filler metal is recommended.

Cold working
Readily fabricated by most cold working methods, 304 may require intermediate annealing to avoid cracking or tearing from radical deformation. Full annealing should follow any operation to reduce internal stress and optimize corrosion resistance.