DILLIMAX 690

High strength structural steel (quenched and tempered)

DILLIMAX 690 is a high strength quenched and tempered, fine grained structural steel with a minimum yield strength of 690 MPa in its delivery condition (referring to the lowest thickness range). Its mechanical properties are achieved by water quenching followed by tempering.

DILLIMAX 690 is preferentially used for welded steel structures within mechanical constructions, plant constructions and structural steel works, such as machines for structural engineering, conveying plants, hoists, cranes, flood gates, bridges and frameworks.

Dimensions

Thicknesses (mm) Formats (mm)
10 - 120 2000 × 6000

Product description

DILLIMAX 690 can be delivered in three qualities:

  • DILLIMAX 690 B
    Steel number 1.8931 - S690Q according to EN 10025-6 with minimum impact values down to -20 °C
  • DILLIMAX 690 T
    Steel number 1.8928 - S690QL according to EN 10025-6 with minimum impact values down to -40 °C
  • DILLIMAX 690 E
    Steel number 1.8988 - S690QL1 according to EN 10025-6 with minimum impact values down to -60 °C

DILLIMAX 690 can be delivered as basic grade (B) or tough grade (T) in thicknesses from 6 to 250 mm, as extra tough grade (E) in thicknesses from 6 to 200 mm according to the dimensional program. Dimensions, which deviate from the usual dimensional program, may be possible on request.

DILLIMAX 690 fulfils the requirements of EN 10025-6.

Tolerances

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 possible on request prior to order.

Chemical composition

Typical values (weight %).

C Si Mn P S Cr Ni Mo B V + Nb
≤ 0.20 ≤ 0.50 ≤ 1.60 ≤ 0.02 ≤ 0.01 ≤ 1.50 ≤ 1.80 ≤ 0.60 ≤ 0.004 ≤ 0.10

The steel is fine grained through sufficient aluminium content. Furthermore, the limiting CEV 2values indicated by PR EN 10025-6 are respected. Lower carbon equivalent values can be guaranteed on request.

The limiting CEV values are lower than the values given in EN 10025-6:

Thickness (mm) C Si
≤ 25 0.50 0.65
25 - 50 0.55 0.65
50 - 100 0.67 0.77
100 - 150 0.75 0.83
150 - 250 0.78 ×

Surface quality

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

Supply conditions

Water quenched and tempered according to EN 10025-6. Unless otherwise agreed, the general technical delivery requirements in accordance with EN 10021 apply.

Mechanical properties in delivery conditions

Tensile test at ambient temperature - transverse test specimens

Thickness (mm) YS (MPa) UTS (MPa) E (%)
≤ 65 690 770 - 940 14
65 - 100 670 770 - 940 12
100 - 150 630 720 - 900 12
150 - 200 610 700 - 880 12
200 - 250 600 690 - 870 12

Testing

Tensile and impact tests will be performed according to EN 10025-6 once per heat and 40 t. Tests on every heat treated plate may be possible on request. The test pieces are taken and prepared according to part 1 and 6 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. Tensile tests according to ASTM A370 may be agreed. 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 at the lowest temperature of the corresponding quality on transverse test pieces.

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

Identification of plates

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

  • steel grade (e.g. DILLIMAX 690 B, T or E) ; heat number;
  • number of mother plate and individual plate;
  • the manufacturer’s symbol;
  • authorized inspection representative’s sign.

General technical delivery requirements

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

Tolerances

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 possible on request prior to order.

Processing information

The entire processing and application techniques are of fundamental importance to the reliability of 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 of the EN 1011-2 (Welding) and CEN/TR 10347 (Forming) as well as recommendations regarding job safety in accordance with national rules should be observed.

Hot forming

If the temperature of 560 °C is exceeded, the initial tempering will be altered so that the mechanical properties are affected.

To regain the initial properties new quenching and tempering become necessary. However, water quenching of a formed workpiece or component will often be less effective than the original quenching in the plate mill so that the fabricator may not be able to reestablish the properties required and therefore hot forming may not be suitable. In this respect we recommend you to contact the steel producer prior to ordering, in all cases where hot forming is required.

Finally, it is the fabricator’s responsibility to obtain the required values of the steel through an appropriate heat treatment.

Cold forming

Cold forming means forming below the maximum allowable stress relief temperature (560 °C). DILLIMAX 690 can be cold formed with regard to its high yield strength. Flame cut or sheared edges in the bending area should be ground before cold forming. Cold forming is related to a hardening of the steel and to a decrease in toughness. Some codes may limit the maximum permissible strain during cold forming. Depending on the relevant code this can result in the need of larger bending radiuses than indicated in the chart. For larger cold forming amounts we recommend you to consult the steel producer prior to ordering.

During the processing, the necessary safety measures have to be taken, so that nobody will be exposed to a danger by a possible fracture of the work piece during the forming process.

The following geometries can usually be achieved by cold forming without the formation of surface defects (where t is the plate thickness):

  Internal minimum radius Die opening minimum
Transversal 2 × th 7 × th
Longitudinal 3 × th 9 × th

Welding and flame cutting

Due to its high yield strength, DILLIMAX 690 requires special care during plate processing. For flame cutting, the following minimum preheating temperatures are recommended : 25 °C for plate thickness up to 20 mm, 50 °C for plate thickness up to 50 mm, 100 °C for plate thickness up to 100 mm, 150 °C for plate thickness up to 200 mm and 180 °C for thicker plates.

For general welding instructions, please consult the EN 1011. In order to ensure that the tensile strength of the weld metal fulfils the requirements of the base metal, the heat input and interpass temperature must be limited during welding. Experience has shown that the welding conditions should be chosen so that the cooling time t 8 / 5 does not exceed 20 seconds. This is applicable when using suitable filler materials of a corresponding yield strength class.

The high yield strength of the base material must be taken into account when choosing the filler materials. It should be considered that increased heat input leads to lower tensile properties in the weld metal. If a stress relieving heat treatment is planned during or after plate processing, this must also be considered when selecting the filler materials. To avoid hydrogen-induced cold cracking, only filler materials, which add very little hydrogen to the base metal, may be used. Therefore, 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), and dried according to the manufacturer’s instructions, should be used.

Heat treatment

If a stress relieving has to be considered because of constructional regulations, constructive reasons or because it is necessary for plate processing, please consult us. The properties of structural components can be altered by a stress relief heat treatment.