The typical chemical composition for this grade is given in the table below, together with composition limits given for the product according to different standards. The required standard will be fully met as specified on the order.

The chemical composition is given as % by mass.

The mechanical properties of the available products in soft annealed condition at room temperature are given in the table below. Moderate strengths can be reached at elevated temperatures (~550 °C/1022 °F). Temperatures for excessive scaling are close to 850 °C/1562 °F. This grade, along with other austenitic corrosion-resistant steels, exhibits very high ductility and high elongation to fracture. It is not susceptible to brittle fracture in the solution annealed condition.

¹⁾Elongation according to EN standard:
A₈₀ for thickness below 3 mm.
A for thickness = 3 mm.
Elongation according to ASTM standard A_2” or A₅₀.

Core 305/4303 has excellent corrosion resistance in solutions of many halogen-free organic and inorganic compounds over a wide temperature and concentration range. It can withstand many organic and sufficiently diluted mineral acids depending on the temperature of the solution. Core 305/4303 may suffer from uniform corrosion in mineral acids and hot strong alkaline solutions. Due to its increased nickel content, its uniform corrosion resistance usually matches or supersedes the corrosion resistance of basic austenitic CrNi standard grades 4301 and 4307. More detailed information on the corrosion properties of Core 305/4303 can be found in Outokumpu’s Corrosion Tables published in the Outokumpu Corrosion Handbook and on www.outokumpu.com.

In aqueous solutions containing halogenides, e.g. chlorides or bromides, pitting and crevice corrosion may occur depending on halogenide concentration, temperature, pH-value, concentration of oxidizing compounds, or crevice geometry, if applicable. For a short period of time, for instance during cooking of food in stainless steel dishes, Core 305/4303 can tolerate even relatively high chloride concentrations. The presence of corrosion-inhibiting or accelerating compounds like transition metal ions or organic compounds may influence the corrosion behavior of Core 305/4303.

Core 305/4303 is prone to chloride-induced stress corrosion cracking at temperatures over about 50°C depending on the applied stress and the chloride concentration in the environment. Due to its high nickel content, it withstands, however, stress corrosion cracking slightly better than the other austenitic CrNi standard grades with lower nickel content. Prior cold deformation of the structure under load increases the risk of stress corrosion cracking.

Core 305/4303 can be used for indoor and outdoor applications in rural areas and urban environments where chloride contamination is low. The best material performance is usually reached with the help of adequate design, correct post-weld treatment, and regular cleaning during use (if applicable).

PRE Pitting Resistant Equivalent calculated using the formula: PRE = %Cr + 3.3 x %Mo + 16 x %N
CPT Corrosion Pitting Temperature as measured in the Avesta Cell (ASTM G 150), in a 1M NaCl solution (35,000 ppm or mg/l chloride ions).
CCT Critical Crevice Corrosion Temperature is the critical crevice corrosion temperature which is obtained by laboratory tests according to ASTM G 48 Method F

For more information on corrosion resistance, please to the Outokumpu Corrosion Handbook or contact the Outokumpu corrosion experts.

Physical properties according to EN 10088 are given in the table below.

*) Austenitic stainless steel grades may be magnetizable to a certain degree after cold deformation, e.g. in temper rolled condition.

Cold forming

Core 305/4303 is excellent in cold forming applications like heading, drawing, and bending.

Welding

Austenitic Core 305/4303 has excellent weldability and is suitable for the full range of conventional welding methods (like MMA, MIG, MAG, TIG, SAW, LBW, or RSW), except gas welding. Core 305/4303 has about 50% higher thermal expansion and lower heat conductivity compared to carbon steels. This means that larger deformation and higher shrinkage stresses may result from welding.

In thin sections, autogenous welding may be used. In thicker section, the low-carbon Core 304L/4306 is preferred, and to ensure that the weld metal properties (e.g. strength, corrosion resistance) are equivalent to those of the parent metal, matching or slightly over-alloyed fillers should preferably be used.

The recommended filler metal is 19 9 L.

Post-weld heat treatment is generally not required. In special cases where there is high risk of stress corrosion cracking or fatigue, stress relief treatment may be considered.

In order to fully restore the corrosion resistance of the weld seam, the weld discoloration should be removed by pickling and passivation.

Because of the austenitic structure, the welded joints are tough down to low temperatures even in the as-welded condition.

More detailed information concerning welding procedures can be obtained from the Outokumpu Welding Handbook, available from our sales offices.

The most commonly used international product standards are given in the table below.