DIWETEN 355+N

DIWETEN 355+N is used for instance in steel constructions like bridges and buildings.

Cold forming means forming below the maximum allowable stress relief temperature (generally < 580°C). DIWETEN 355+N can be cold formed as any comparable structural steel in accordance with EN 10025. In case of higher cold forming ratios, i.e. edging on mechanical presses, it is advisable to consult the steel manufacturer prior to placing the order.

Atmospheric corrosion resistance means that DIWETEN 355+N - due to its chemical composition - presents an improved resistance against atmospheric corrosion because of the forming of an auto- protective layer on the base material depending on weather condition having a succession of dry and wet periods. This layer protects the surface and slows down the normal rust formation.

Generally, the corrosion velocity decreases with increasing service life. Even after the formation of the patina, a total stop of the corrosion process is not achieved.

However, the patina offers - in comparison to unalloyed steels - a better protection against atmospheric corrosion in industrial, city or rural atmospheres, enabling the application of uncoated steels under certain circumstances.

Initial formation, time of development and protective effect of the patina on steels with improved atmospheric corrosion resistance are extremely depending on the constructional design and the atmospheric and environmental conditions in the respective case.

In any case, usual constructional standards for the construction with steels with improved atmospheric corrosion resistance are to be observed, as i.e. the German guideline DASt 007 (“Lieferung, Verarbeitung und Anwendung wetterfester Baustähle”) or the Cerema/Ifsttar French information note “Aciers autopatinables, recommandations pour leur utilisation en structure des ponts et passerelles”.

In addition, the weather resistance index of I > 6.0 in accordance with ASTM G101-04 (2015) is valid.

I = 26.01 · (% Cu) + 3.88 · (% Ni) + 1.2 · (% Cr) + 1.49 · (% Si) + 17.28 · (% P) – 7.29 · (% Cu) · (% Ni) - 9.10 · (% Ni) · (% P) – 33.39 · (% Cu)2.

Normalized or normalizing rolling in accordance with EN 10025-5 (short designation +N).

General technical delivery requirements: Unless otherwise agreed, the general technical delivery requirements in accordance with EN 10021 apply.

DIWETEN 355+N has an excellent weldability under the condition that the general technical rules (see EN 1011) are observed. The fabrication by flame cutting and welding has to be carried out similarly to unalloyed structural steels of EN 10025-2 of the same strength and dimensions. However the hardenability of the steel is increased due to the Cu and Cr alloying. The preheat conditions must be adapted to the increased carbon equivalent. If necessary, the corrosion resistance of the welding deposit has to be assured by selection of adequate weld metals or other anti-corrosion measures.

If particular requirements, which are not covered in this material data sheet, are to be met by the steel due to its intended use or processing, these requirements are to be agreed before placing the order.

The information in this technical data sheet is a product description. This material data sheet is updated at irregular intervals. The current version is available from the mill or as download at www.dillinger.de.

Welded joints of DIWETEN 355+N are usually used in welded condition. If a stress relief heat treatment is necessary, a temperature of maximum 580 °C and a holding time of maximum 60 minutes with a heating and cooling speed of 70 - 80 °C/h are recommended.

Hot forming means forming at temperatures above AC3 (~ 900 °C; austenitic phase). If possible, the hot forming has to be carried out at the normalizing temperature with following cooling in still air (see CEN/TR 10347).

1) Weld bead bend test in accordance with SEP 1390 (Edition 1996)

2) Tensile and impact test on each mother plate,

3) Supplementary Charpy-V-test: absorbed energy KV2 27 J at -50 °C as the average of 3 tests and minimum single value of 19 J, applicable in the sense of S355J5W+N.

DIWETEN 355+N can be delivered in thicknesses from 8 to 150 mm according to Dillinger delivery program.

DIWETEN 355+N is certified as DIWETEN 355+N/S355J2W+N or DIWETEN 355+N/ S355K2W+N or with the order option 3 as DIWETEN 355+N/ S355J5W+N in thicknesses up to 150 mm. The CE- marking certificate is issued in accordance with EN 10025-1, unless otherwise agreed. Under the designations DIWETEN 355+N/S355J2W+N and DIWETEN 355+N/S355K2W+N, the „marque NF-Acier“ can be applied in thicknesses up to 150 mm according to NF EN 10025-5.

For plate thickness > 30 mm, DIWETEN 355+N can be delivered with additional weld bead bend test in accordance with SEP 1390 (edition 1996) if specified at the time of the order (option 1).

The entire processing and application techniques are of fundamental importance to the reliability of the products made from this steel. The user should ensure that his design, construction and processing methods are aligned with the material, correspond to the state-of-the-art that the fabricator has to comply with and are suitable for the intended use. The customer is responsible for the selection of the material. The recommendations in accordance with EN 1011-2 and guideline DASt 007 as well as recommendations regarding job safety in accordance with national rules should be observed.

Surface quality: Unless otherwise agreed, the specifications will be in accordance with EN 10163-2, class A2.

Ultrasonic testing: Unless otherwise agreed, DIWETEN 355+N meets the requirements of class S1E1 in accordance with EN 10160.

Tensile test at ambient temperature – transverse test specimens

Tensile and impact tests will be performed according to EN 10025-5 once per heat, 60 t and thickness range as specified for the yield strength. If agreed at the time of the order, the tests could be performed on each mother plate (option 2). The preparation of the test units occurs in accordance with EN 10025-1 and EN10025-5. The tensile test is carried out in accordance with EN ISO 6892-1 on specimens of gauge length Lo = 5.65·√So resp. Lo = 5·do. Unless otherwise agreed, the impact test is carried out at -20 °C (at -50 °C for option 3 on longitudinal Charpy-V-specimens using a 2 mm striker in accordance with EN ISO 148-1. Unless otherwise agreed, the test results are documented in a certificate 3.1 in accordance with EN 10204.

Unless otherwise agreed, tolerances are in accordance with 10029, with class A for the thickness.