DI-MC 690 T

DI-MC 690 (only the unwelded plate) can be cold formed at temperatures below 580 °C taking into account its high yield strength. Irregularities in the bend area of the flame cut (cratering, blow-out, deep drag lines) should be ground smooth before cold forming, in order to avoid stress concentration. Cold forming is always related to a hardening of the steel and to a decrease in toughness. If a heat treatment of unwelded cold formed parts becomes necessary, please contact us prior to the ordering.

DI-MC 690 can be delivered in two qualities as follows:

Due to its high yield strength, the processing of DI-MC 690 requires special care. DI-MC 690 needs no preheating for flame cutting.

DI-MC 690 needs no preheating for flame cutting. For general welding instructions, please follow the reco mmendations of EN 1011.

DI-MC 690 has a low carbon content and a low carbon equivalent, which leads to a low hardness increase and a decreased susceptibility to cold cracking. Nevertheless preheating may be necessary to avoid cracks in the weld metal, due to the sensitivity of high strength filler materials. Thus only welding consumables adding very little hydrogen to the weld shall be used. Shielded arc welding should be preferred. For manual arc welding, electrodes with basic coating (type HD < 5 mL/100 g in accordance with ISO 3690) should be used after drying according to the manufacturer’s instructions. Heat treatment for hydrogen effusion (soaking) immediately after welding is reco mmended in case of increasing plate thicknesses and high restraint welds.

The high yield strength of the base material must also be taken into account while selecting the filler materials. In order to ensure that the tensile strength of the weld metal fulfils the requirements of the base material, the heat input and interpass temperature must be limited during welding. This is applicable when using suitable filler materials of a corresponding yield strength class. DI-MC 690 is suitable for a post-weld stress relieving of welded structural components up to 580 °C. The holding time should not exceed 1.5 hours (even if multiple operations are carried out). Cooling rate after PWHT should not be lower than 75 °C/h for temperatures above 300 °C.

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.

If a stress relieving has to be considered because of design codes, constructive reasons or because it is necessary during the fabrication, the above mentioned conditions can be applied. The properties of structural components can be altered by a stress relief heat treatment.

Hot forming is not allowed for thermomechanically rolled steel, because the particular microstructure would be altered. Consequently the forming of DI-MC 690 at temperatures above 580 °C without a significant deterioration of its mechanical properties is not possible and so shall not be applied.

Optionally it is possible to order DI-MC 690 with additional impact testing at 0 °C with a minimum average value of 100 J (single value 70 J).

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

The steel is fully killed and fine grain treated.

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 should be observed.

Unless otherwise agreed, the technical data sheet will be in accordance with EN 10163, class A2. Higher requirements may be agreed on request.

Tensile and impact tests, and on request bend tests, are carried out once per heat and 40 t. Tests on every mother plate are possible on request.

The tensile test is carried out on flat rectangular specimens of gauge length Lo = 5.65⋅√So or 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 at a temperature of -20 °C for basic quality B and at -40 °C for low-temperature quality T in longitudinal direction close to the surface.

The bend test will be carried out according to EN ISO 7438.

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

Bend test: Formabilty of the transverse test specimen subjected to the bend test:

bending angle 180 °; mandrel diameter ≥ 4 x specimen thickness

A smaller mandrel diameter can be agreed on request.

Unless otherwise agreed, the tolerances will be in accordance with EN 10029, with class A for thickness and table 4, steel group H, for the maximum flatness deviation. Smaller flatness deviations may be agreed on request.