DBL_4093_2008-06

June 2008

Mercedes-Benz

Supply Specification

Body components manufactured from press-hardened steel sheets

DBL 4093

BQF available Additional DaimlerChrysler Standards required: DBL 7391, DBL 8457, PPAP PWT 4101, MB Special Terms, VDA 621-415

Supersedes Edition: 07.2006

Refer to Section Changes on page 6

Continued on pages 2 to 8

Issued by: Daimler AG

D-70546 Stuttgart

Standardization (GR/EQS)

Technical responsibility (name): H. Bold Department: PWT/VFT

Plant:

050

Phone: 07031/90-2289 HPC: F155 Technical coordination by Central Materials and Process Engineering

Plant 50, Department PWT/VFT Name: H. Hopf Telephone +49(0)703190-7031 90-2562

Confidential! All rights reserved. Distribution or duplication without prior written approval of Daimler AG is not permitted.

In case of doubt, the German language original should be consulted as the authoritative text.

Product versions and examples

Product version Construction Application examples DBL 4093.00

Press-hardened components

made of bright sheet steel Body components for areas not stressed by corrosion 1

DBL 4093.10

Press-hardened components made of sheet steel with hot-dip aluminum finish

Body components such as A-pillars, B-pillars, roof frames and others, as well as side impact beams and cross beams underneath bumpers DBL 4093.20

Press-hardened components made of sheet steel with

continuous hot-dip galvanized finish

As under product version .10

DBL 4093.90 Press-hardened components made of sheet steel with thermal diffusion zinc coating

As under product version .10

Abbreviated designations

On drawings, in the block for material e.g: Steel DBL 4093.10

in more recent drawings, the DBL for finish and delivery shall be entered in the block for material.

1 Field of application, general requirements

This Supply Specification applies to sheet metal parts for the body structure. These are boron-alloyed steels similar to 22MnB5 which are matched to the hardening process in the press die following heat treatment (austenitization) in the furnace under inert gas or air atmosphere.

Press-hardened components are produced by heating metal sheets or preformed components to a temperature of approx. 900°C, followed by forming and quick cooling in the press die.

1

Product version .00 (bright) shall only be used following approval by the specialist corrosion department (EP/CRK).

2 General properties of the materials, raw materials and supply condition

The materials used for press-hardened components are not standardized with regard to their range of analysis and technological parameters. The product version of this DBL determines the technological properties of the components; see Table 2.

The grades described in this DBL are ultrahigh strength steels with tensile strengths of up to R m = 1600 N/mm². In order to prevent any hydrogen-induced brittle fractures, care shall be taken to ensure that hydrogen absorption is avoided during the complete manufacturing process and during use in the vehicle.

3 Dimensions and tolerances / Form of supply

3.1 Dimensions and tolerances

For the input stock, the thickness tolerances for continuously hot-dip coated steel sheet and strip in accordance with EN 10143 and continuously hot-rolled uncoated plate, sheet and strip in accordance with EN 10051 shall apply.

4 Technical data

4.1 Input stock

4.1.1 Base materials

For all product versions, the base material corresponds to boron-alloyed steel similar to 22MnB5. The designation 22MnB5 describes commercially available grades. It is intended as an example of the manufacturers' grades which fulfilled the requirements of this DBL at the time of going to print.

4.1.2 Coating

Product versions .10 and .20 are protected against scaling and corrosion by their hot-dip refining process. Product version .10 is hot-dip coated with an aluminum silicon coating AS150 in accordance with DIN EN 10327. In this process, the strip is guided through molten aluminum with approx. 8 – 11 % silicon.

Product version .20 is hot-dip coated with a plating of zinc Z200 in accordance with DIN EN 10327. The relevant layer consists of approx. 99% zinc.

The coating shall be determined in accordance with DIN EN 10327 using the single spot test, and possesses the values according to Table 1.

Table 1: Tolerances of the coating of the input stock

Values / side

Product version

Thickness / μm Minimum coating mass / g/m²

.10 19 - 33 58 .20 10 - 20 85