Stainless steel is a particularly pure, alloyed or unalloyed steel. In the case of the high-alloy stainless steels offered by teknow, alloying elements such as chromium, nickel, molybdenum and titanium are added. These are the steels known as “rustproof” in everyday use. The corrosion resistance is particularly determined by the chromium content, which must exceed 13%. Chromium reacts with oxygen and forms a passive layer of chromium oxide. In the event of mechanical damage, this layer forms again, the steel usually does not rust. Depending on the alloy, the passivation layer can be damaged by rust film, salt or chlorine and acids.
Designation of the stainless steels
High-alloy steels are marked with an X as the leading letter. This is followed by the carbon content x 100, then the symbols for the alloying elements, arranged in descending order of mass.
Examples:
X5CrNi18-10 (V2A or 1.4301) has 0.05% carbon, 18% chromium (Cr) and 10% nickel (Ni)
X6CrNiMoTi17-12-2 (V4A or 1.4571) has 0.06% carbon, 17% chromium (Cr) and 12% nickel (Ni) and 2% molybdenum.
Common names for stainless steel are V2A and V4A. The names are historically and no longer unambiguous today. The V stands for trial (“Versuch”) and the A for austenite, a component of iron with a certain structure. The CrNi steel 1.4301 (X5CrNi18-10) offered by teknow is a V2A steel, the CrNiMo steel 1.4571 (X6CrNiMoTi17-12-2) falls under the V4A steels.
Stainless steel grades
X5CrNi18-10 / 1.4301 is the standard quality of stainless steels, this material is preset in the material selection.
Use: diverse uses: architecture, design, jewelry and art, household items, also in contact with food, scientific instruments, also ultra-high vacuum and cryogenic applications. Can be used up to 600 ° C. Resistant to almost all environmental influences and weak acids.
Warning: Not resistant to chloride ions, therefore not suitable for use in salt water, swimming pools or similar environments.
Processing: Can be welded well electrically, can be polished very well, can be formed very well (deep drawing, folding) Less easily machinable due to the tendency to work hardening and toughness
X6CrNiMoTi17-12-2 / 1.4571 is more resistant to corrosion than 1.4301
Use: Like V2A, but can also be used in salt water and swimming pools due to the better resistance to corrosion. Instrument construction, vacuum technology
Processing: Good weldability, polishable, less machinable by all methods
X10CrNi18-8 / 1.4310 is used as a material for photochemical etching.
Use: Slightly less corrosion-resistant than 1.4301 due to a lower nickel content, generally good resistance to food and beverages. Suitable for spring production for operating temperatures up to over 200 ° C.
Processing: very good cold formable (deep drawing, folding), with work hardening and magnetisability through the forming. Not very easy to machine.