X8CrNiS18-9 / AISI 303 / 1.4305 steel is a stainless steel, chromium-nickel, austenitic structure, resistant to corrosion.
All corrosion-resistant steels according to the European standard are marked with the first letter X, followed by the carbon content given in hundredths of % and the main symbols of alloying elements determining their properties along with their content, i.e. 18% Cr and 9% Ni. In addition, this steel contains C ≤ 0.15%, Mn ≤ 2%, Si ≤ 1%, Cu ≤ 1% and a sulfur content of 0.15-0.35%.
The sulfur addition was added to improve machining and the formation of a short chip, as well as to increase cutability. Due to limited resistance in acidic and chloride environments, pitting or pit corrosion may occur. The presence of sulfur in the chemical composition reduces the weldability of components and causes intergranular corrosion. It is most commonly used in the food and dairy industries, the photographic industry, as well as the chemical and textile industries.
The material is well suited for cold drawing, but poor for cold forming and cold rolling. X8CrNiS18-9 stainless steel is difficult to forge and requires high temperatures (1150°C to 950°C), with the risk of overheating and hot cracking. In combination with seawater or salt, it does not show resistance to intergranular corrosion.
Stainless steel X8CrNiS18-9 / AISI 303 / 1.4305 chemical composition
A very important factor determining the mechanical properties of a given steel is its chemical composition. According to melt analysis, the chemical composition of X8CrNiS18-9 steel should be in accordance with the values given in the table below.
| Designation | C in % max. | Cr % max | Ni % max | Mn % max. | P % max. | S % max. | Si % max. | |
|---|---|---|---|---|---|---|---|---|
| X8CrNiS18-9 | 1.4305 | 0,15 | 17,0 - 19,0 | 8,0 - 10,0 | 2,0 | 0,20 | 0,15-0,35 | 1,0 |
Steel X8CrNiS18-9 / AISI 303 / 1.4305 mechanical properties
| Steel | Mechanical properties | |||
|---|---|---|---|---|
| Steel mark | Rp0.2 [MPa] | Rm [MPa] | HB | Elongation [%] |
| X8CrNiS18-9 | ≥ 190 | 500 - 700 | ≤230 | ≥35 |
X8CrNiS18-9 / AISI 303 / 1.4305 steel application
X8CrNiS18-9 steel is typically used as stainless steel hall, often for decorative elements. The main areas of application are:
- automotive industry,
- machinery industry,
- textile industry,
- electronic equipment,
- turned components for the food industry.
| EU EN | Steel number | USA AISI | France AFNOR | England BS |
| X8CrNiS18-9 | 1.4305 | 303 | Z8CNF18-09 | 303S31 |
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