DI-MC 355 T: Premium EN S355ML Structural Steel with Superior Weldability

With regard to its high toughness, DI-MC 355 can generally be well cold formed, i.e. at temperatures below 580 °C. Cold forming is always related to a hardening of the steel and to a decrease in ductility. This change in the mechanical properties can in general be partially recovered through a subsequent stress relief heat treatment. Flame cut or sheared edges in the bending area should be ground before cold forming. For larger cold forming degrees we recommend consulting us before ordering.

DI-MC 355 can be delivered in two qualities as follows:

DI-MC 355 can be flame cut in all thickness ranges without preheating. Plasma and laser cutting can also be carried out without preheating for typical thickness.

DI-MC 355 has an excellent weldability if the general technical rules are observed (EN 1011 has to be applied analogously). The risk of cold cracking is low, so that preheating is often not necessary when welding. With greater plate thicknesses, omitting the preheating requires the use of filler materials and welding conditions that lead to a very low hydrogen transfer (up to 5 ml/100 g DM according to ISO 6390).

The low content of carbon and other alloy elements leads to favourable toughness properties in the heat affected zone, even with high heat inputs. Depending on the chosen welding process, welding filler material as well as toughness requirements in the heat affected zone, it permits cooling temperatures (t8/5) above the limiting values of 25 s as stated in EN 1011-2 and SEW 088.

For flame straightening, working recommendations are given in the “DI-MC Processing instructions Flame straightening”. For thermomechanically rolled steel the report CEN/TR 10347 recommends the same maximum flame straightening temperature as for normalized steel.

If special 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 data sheet is a product description. This data sheet is updated at irregular intervals. The current version is relevant. The current version is available from the mill or as download at www.dillinger.de.

Welded joints of DI-MC 355 are usually used in welded condition. If a stress relief heat treatment is necessary, it is carried out in the temperature range between 530 and 580 °C with cooling in air. The holding time should not exceed 4 hours (even if multiple operations are carried out). For particular heat treatment requirements we recommend consulting us before ordering.

Hot forming, i.e. forming at temperatures above 580 °C, leads to changes in the original material condition. It is impossible to re-establish the same material properties that had been achieved during the original manufacture through a further heat treatment. Therefore hot forming is not permitted.

Optionally it is possible to order DI-MC 355 in the whole thickness range (up to 150 mm) with a minimum yield strength of 355 MPa, as well as a tensile strength range of 470 MPa (see option 1).

Options:

1) Yield strength of 355 MPa, as well as a tensile strength range of 470 MPa independent of plate thickness.

2) The impact properties and the tensile properties shall be verified for each mother plate

Identification: Unless otherwise agreed, the marking is carried out via steel stamps with at least the following information:

The entire processing and application techniques are of fundamental importance to the reliability of the parts and assemblies 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 and SEW 088 should be observed. You find detailed information on processing in the “DI-MC Processing instructions”.

Unless otherwise agreed, the specifications will be in accordance with EN 10163, class A2

Tensile test and impact tests are carried out once per heat, 60 t and thickness range as specified for the yield strength according to table 5 of EN 10025-4. Tests on every mother plate are possible on request (see option 2).

The test pieces are taken and prepared according to parts 1 and 4 of EN 10025.

The tensile test is carried out on specimens of gauge length Lo = 5.65⋅√So respectively Lo = 5⋅do, in accordance with EN ISO 6892-1. The impact test will be carried out on Charpy-V-specimens in accordance with EN ISO 148-1 using a 2 mm striker. Unless otherwise agreed, the test will be performed according to EN ISO 148-1 on longitudinal test pieces at a temperature of -20 °C for the basic quality B and at -50 °C for the low temperature quality T.

Unless otherwise agreed, the test results are documented in a certificate 3.1 in accordance with EN 10204.

Unless otherwise agreed, DI-MC 355 meets the requirements of class S1E1 in accordance with EN 10160.

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