Stainless Steel Grade AISI 303 | EN 1.4305

AISI 303 | EN 1.4305 | DIN X8CrNiS18-9 is an austenitic, corrosion-resistant stainless steel with the addition of sulfur to improve cutting properties (randomly machined steel). Its corrosion resistance is limited in acidic and chloride environments. When used in such environments, pitting or strip corrosion may occur.

It has relatively good resistance to atmospheric corrosion with some limitations, especially in marine and coastal environments. It also has good resistance to many (slightly corrosive) organic and inorganic chemicals. Slightly less corrosion resistance than EN 1.4307 due to the addition of sulphur. Residual cutting fluid must be removed by degreasing. The surface must be passivated after treatment to achieve better corrosion resistance.

The steel is susceptible to intergranular corrosion due to extreme precipitation of chromium carbide grains, which can occur in the temperature range of 550 ºC - 850 ºC. Resistance to pitting and crevice corrosion is low and / or moderate. These types of corrosion usually occur in acidic, neutral or slightly alkaline solutions and in low chloride environments. The grade is susceptible to stress corrosion cracking. Critical service conditions should be avoided, i.e. applications subject to a combination of tensile stress, temperatures above 50 ºC and chloride-containing solutions.

Welding

This grade of material is designed to optimize machinability. The high sulfur content makes it very susceptible to hot cracking during welding and therefore welding of this steel is not recommended.

Processing

AISI 303 | EN 1.4305 | DIN X8CrNiS18-9 is a stainless steel with free processing and intended for further processing by mechanical processing. The steel is alloyed with sulfur 0.15 - 0.30%, which creates a significant amount of sulfides in the material. Sulfides improve machinability and, in particular, chip destruction, but have a drawback that in fact worsens weldability, impact toughness, corrosion resistance and good machinability.

Mechanical properties

Table: mechanical properties of stainless steel grade AISI 303 | EN 1.4305 | DIN X8CrNiS18-9
Tensile strength, min., MPa	500-750
Yield strength, 0.2%, MPa	190
Relative elongation, min., %	35
Hardness, HB type	230

Physical properties

Table No. 1: physical properties of stainless steel grade AISI 303 | EN 1.4305 | DIN X8CrNiS18-9
Density g/cm³	7,9
*Specific heat capacity at +20°C, J/kgK**	500
*Thermal conductivity at +20°C, W/mK**	15
*Specific electrical resistance at +20°C, μOhmm**	0,73
Magnetic properties	non-magnetic

Table No. 2: physical properties of stainless steel grade AISI 303 | EN 1.4305 | DIN X8CrNiS18-9
Temperature	+20°С	+100°С	+200°C	+300°С	+400°С	+500°С
Modulus of elasticity, GPa	200	194	186	179	172	165
Coefficient of linear expansion, 10^-6/°C	-	16,5	16,5	17,0	17,5	18,0

Table: chemical composition of steel grade AISI 303 | EN 1.4305 | DIN X8CrNiS18-9
Chemical composition of steel grade AISI 303 \| EN 1.4305 \| DIN X8CrNiS18-9
C	Si	Mn	P	S	Cr	Ni	N	Fe
<0,10	<1,00	<2,00	<0,045	0,15-0,35	17,0-19,0	8,0-10,0	<0,10	Other

Application

Stainless steel AISI 303, despite poor weldability, has found wide application:
- in the chemical industry;
- in the food industry;
- in the production of rolled metal (sheets, strips);
- in the production of pipeline system elements;
- in the construction of frame structures for which strength and long service life are important.

In addition, AISI 303 steel is used to manufacture products that operate in atmospheric conditions. Stainless steel AISI 303 (aisi303) is used to produce cold-rolled sheets, strips, angles with increased strength, various metal structures used in pipeline systems. It is used to produce turned parts for the food and dairy industries, the photographic industry, paint and varnish, oil, soap, paper and textile industries.