Indaten® HC315WP cold rolled steel offers improved resistance to atmospheric corrosion and is a thin gauge version of the hot rolled steel defined in the EN 10025-5:2004 standard (S355J0WP). It is a fine-grain, high-strength structural steel that has been optimised to give improved processing and in-service performance.


When used uncoated and exposed to weather conditions, an oxide layer develops on the steel surface, forming a purplish-brown, finely grained patina that bonds very strongly to the steel and protects it. With its characteristic colour, Indaten® HC315WP steel is used in architectural projects either to harmonise with the environment or to create a pleasing contrast with other materials, such as stainless steel. If the patina is damaged, the steel re-oxidises, thus repairing the patina and maintaining the protective barrier.


Indaten® HC315WP can also be coated (paint, metallic coatings etc). In the case of coated parts, the protective layer prevents rust propagation under the paint layer.

Experience has shown that the adhesion of paint on Indaten® HC315WP is superior to bonding on other carbon steel grades.


Indaten® HC315WP has a wide range of applications: architecture, sculpture, civil engineering structures, HVAC equipment, containers and cable trays. When used uncoated, no maintenance is required and the material will not deteriorate through corrosion.


The effectiveness of the corrosion protection largely depends on the speed of patina formation. For optimum patina formation, Indaten® HC315WP can be used in a non-confined environment, even in the presence of sulphuric fumes. However, it is strongly recommended not to expose Indaten® HC315WP to condensation, constant humidity or repeated soiling, particularly in environments containing free chlorine.


Indaten® HC315WP has excellent weldability with all the usual welding processes thanks to its low carbon content and fine-grained structure.

Recommendations for use

Appearance of the patina


Outdoor use: the patina forms naturally in the open air (over a maximum of three to four years and generally faster). Variations in appearance will be observed, depending on the water condensation, evacuation and evaporation conditions. After a few years, the patina will stabilise, even in an industrial, sulphur-containing or rural environment. To ensure optimum patina formation and limit the formation of rust streaks, the oxidation process can be accelerated artificially by first degreasing the surface and then subjecting it to alternate periods of dry and humid conditions.


Indoor use: to preserve the natural appearance of the material and at the same time avoid powdery oxide deposits that may cause staining, the following three steps are recommended:


Use painted: as the surface has a high reactivity, it is recommended that the first coat of paint be applied on a clean surface immediately after degreasing.

Brand correspondence

 EN 10025-5:2004 (1)
Indaten® HC315WP S355J0WP (1)
(1) These grades have the same analytical requirements so as to obtain the same properties in terms of patina formation.



Thickness (mm)Min widthIndaten® HC315WP
Max width
0.50 ≤ th < 0.609001370
0.60 ≤ th < 1.001550
1.00 ≤ th < 1.401680
1.40 ≤ th < 1.801840
1.80 ≤ th < 3.001880

Mechanical properties

Thickness (mm)
Re (MPa)
Rm (MPa)
A80 (%)
Indaten® HC315WPT0.4 - 3≥ 315≥ 450≥ 22

Chemical composition

C (%)
Mn (%)
P (%)
S (%)
Si (%)
Al (%)
Cu (%)
Cr (%)
Ni (%)
N (%)
Ceq (%)
Indaten® HC315WP ≤ 0.120 ≤ 1.00 0.060 - 0.150 ≤ 0.015 0.20 - 0.50 ≥ 0.020 0.25 - 0.55 0.30 - 0.80 ≤ 0.30 ≤ 0.009 ≤ 0.45

The alloy components give Indaten® HC315WP its corrosion resistance properties.


The presence of copper in the oxide layer contributes to the formation of a strongly bonded, elastic and compact patina on the surface of Indaten® HC315WP in the course of the corrosion process. The chromium and nickel contribute to the formation of insoluble alkaline sulphates, which will seal the pores of the oxide layer, thereby protecting the metal from water and oxygen. Silicon, and to a lesser extent phosphorus, also has a favourable effect on corrosion resistance.

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All details provided in the ArcelorMittal Flat Carbon Europe S.A. catalogue are for information purposes only. ArcelorMittal Flat Carbon Europe S.A. reserves the right to change its product range at any time without prior notice.