TOPOCROM® – Texturing: Technology and Advantages

Thomas Routschek Salzgitter Flachstahl GmbH, Salzgitter (Germany)

Karl Müll TOPOCROM Systems AG, Weinfelden (Switzerland)

BAOSTEEL BAC 2013, Shanghai (China)

Ø   TOPOCROM® - Electroplating Technology ◄◄◄

Ø   Demands of the automotive industry on the surface structure of cold rolled sheet metal

Ø   Requirements of the steelmaking industry for texturing technology of working rolls for skin passing mills

Ø   PRETEX Surface Structure: Prospects

Structure of Presentation

TOPOCROM® - Electroplating Technology

TOPOCROM® is a patented Process Technology for Electroplating

of Hard Chromium Coatings with a typical hemispherical Surface Structure

+ +

Texturing of Working Rolls: Comparison of Technologies

TOPOCROM – Technology

+ +

_

SBT + HCr

EDT + HCr

EBT + HCr

SBT EDT EBT

TOPOCROM

TOPOCROM plating reactor

Layout of TOPOCROM - 2 reactor plant (schematically)

TOPOCROM Facility for Steel Works

POSCO, Gwangyang/South Korea

Startup in 2009

Salzgitter Flachstahl, Salzgitter/Germany

Startup in 1996

Difference between conventional texturing technologies and TOPOCROM Texturing

SBT

EDT

EBT

TOPOCROM Idea:

Structure for Texturing will be build up on the top of the ground Roll Body by the special TOPOCROM Hard Chromium Electroplating Process

à Convex Texture

Roll Body

Roll Body

Roll Body

Roll Body

Conventional Texturing Technology:

Structure will be build mechanically or physically

into the surface of the Roll Body

à Concave Texture

Important Features of TOPOCROM® - Texturing

Important Features of TOPOCROM Coatings

Ø  Hemispherical Surface Structure with perfect stochastic Distribution Ø  Adjustable Roughness and Pc Values: Ra ≥ 0,5 µm to Ra ≤ 12 µm

Ø  High Peak Account Values also together with high roughness values

Ø  Adjustable Topography: open to closed Structure Ø  Hardness comparable with normal Hard Chromium Coatings

Variability of TOPOCROM® - Topography:

Open to closed structure

Closed TOPOCROM – Structure

Open TOPOCROM - Structure

Adjustable surface topography with TOPOCROM® - Texturing

open closed

TOPOCROM Texturing: Ra/Pc - values

Adjustable calotte - density of PRETEX surface structure

High amount of lubricant pockets with ideal stochastic distribution

Closed voids

Open voids Material face

Sheet Forming tool

Advantages of PRETEX surface structure

The PRETEX – structure of Salzgitter AG provides unique advantages with all surfaces: Ø  Adjustable density of calottes Ø  Precisely distributed hydrostatic lubrication pockets for improved formability Ø  Ideal stochastic distribution of the lubrication pockets Ø  Customized of roughness and peak account Ø  Unique solution for combining low roughness with high peak accounts

Structure of Presentation

Ø   TOPOCROM® - Electroplating Technology

Ø   Demands of the automotive industry on the surface structure ◄◄◄ of cold rolled sheet metal

Ø   Requirements of the steelmaking industry for texturing technology of working rolls for skin passing mills

Ø   PRETEX Surface Structure: Prospects

Increasing demands of the automotive industry on the sheet metal surface structure

Actual and future demands of the automotive industry on the sheet metal surface structure

Ø  Improved appearance of painted metal sheet surfaces

Ø  Cost saving with paint systems without filler Ø  Improved formability

Ø  Very low abrasion in the forming tool

Ø  Stable surface characteristics along the entire strip width and length

Demands of the automotive industry on the surface structure of cold - rolled sheet metal

Requirements for the

forming process •  High mean roughness values

•  High number of lubrication pockets

•  Even distribution of lubrication pockets

•  Homogeneous friction conditions

Requirements for painting •  Low mean roughness values

•  High number of peak account values

•  Homogenous peak distribution

•  Absolutely stochastic roughness distribution (Avoidance of Moirè-effects)

•  Less short- and longwave structures (Avoidance of Orange peel)

•  Paint adhesion and spreading characteristics

The fine surface structure is applied to the sheet metal surface by skin passing

Actual and future requirements of automotive industry for surface structure of sheet metal:

Appearance of painted metal sheet surfaces

Requirements for paint appearance Ø  Avoiding of Moire΄ – effects Ø  Avoiding of orange peel

Short and Long – Wave Comparison of PRETEX with alternative texturing on galvanized steel sheets

Advantages of PRETEX Ø  Fine surface structure with high peak accounts and low roughness Ø  Absolutely stochastic distribution Ø  Low wave-scan values

Actual and future surface – requirements of automotive industry for painting applications: Cost saving with paint systems without filler

Important factor for surface structure of sheet metall à low waviness •  Filler and base coat are leveling the substrate, but are superposing the cathodic dip coat with a new waviness profile •  Cathodic dip coat is filtering the roughness characteristic, but waviness will be transferred à The capability for leveling the waviness will be reduced by saving the filler

Challenge for Painting Process •  Reduction of production costs, energy demand and CO2 – emission •  Reduction of painting and drying steps à  Saving the filler

Actual and future surface – requirements of automotive industry for painting applications: Cost saving with paint systems without filler

Painting Process 2010: Paint System without filler

Standard VW – Group TL 218 (May 2012)

PRETEX is the ideal sheet surface structure for paint systems without filler

FEA -­‐ Simula+on  of  different  fric+on  condi+ons

Conclusions: l PRETEX  leads  to  a  be/er  formability

l PRETEX  leads  to  a  safer  forming  process

Lower  stresses  and  more

reserve  to  FLC with  PRETEX

good  draw-­‐in

with  Pretex

PRETEX  ( µ =0,088 ) EDT  ( µ =0,109)

draw -­‐ in

25.8  mm

draw -­‐ in

26.7  mm

Actual and future requirements of automotive industry for surface structure of sheet metal: Improved formability

Actual and future requirements of automotive industry for surface structure of sheet metal: Improved formability

Ø  Previously used: DC06 + ZE 75/75 with EDT – Texturing

Ø  Replaced by: DC05 (mod.) + ZE 75/75 BPO with PRETEX – Texturing and Prephosphating

Ø  Cost benefit by changing from DC06 to DC05

Ø  Reduction of cold welding due to the lower friction coefficient of PRETEX + Phosphating

Car Wing

Actual and future requirements of automotive industry for surface structure of sheet metal: Less abrasion in the forming tool

Ø  Previously used: DC05 with SBT – Texturing

Ø  Replaced by: DC05 with PRETEX – Texturing

Ø  Cost neutral in steel price

Ø  30% reducing of lubrication volume

Ø  Reduced cleaning work before cathodic dip coating

Body-contoured seat

Structure of Presentation

Ø   TOPOCROM® - Electroplating Technology

Ø   Demands of the automotive industry on the surface structure of cold rolled sheet metal

Ø   Requirements of the steelmaking industry for texturing technology ◄◄◄ of working rolls for skin passing mills

Ø   PRETEX Surface Structure: Prospects

Actual challenge for the texturing technology

Requirements of the steelmaking industry for texturing technology of working rolls for skin passing mills

Ø  Characteristic and properties of roll texture

Ø  Cost-efficient process for texturing of working rolls Ø  Lifetime of textured working rolls in production Ø  Schedule free rolling

Production of sheet metal surface structure

Very low Roughness Wear and therefore long Life Time à   due to Hemispherical Surface Structure, Multilayer Design and due to the Hardness of Hard Chromium Coatings 3 - 5 times longer Life Time compared to EDT Rolls (+ hard chromium plated) Constant Product Quality with TOPOCROM Rolls from the beginning (no running in-time) à High pressure cleaning of working rolls during operation is necessary

Requirements of steel works for working rolls: Life time of working rolls

Requirements of steel works for working rolls: Schedule free rolling in HDG – Line № 2 of SZFG

TOPOCROM – Texturing Technology: Benefits for Steelmakers

•   Quality advantages for customers regarding formability and paint appearance

•   Customized adjustment of all structure parameters

•   Constant high surface quality of the metal sheets •   Stable surface characteristics along the entire strip width and length

•   Reliable reproducibility

•  Significant increased Roll Life Time •   Reduced number of roll changes

•   Remarkable reduction in grinding and texturing costs •   Increased total service life of the roll and total productivity due to less grinding operations

•   Reduction of roll inventory •   Higher productivity

•   Reduced costs

•   High wear resistance of TOPOCROM – Rolls allows Schedule Free Rolling •   Increased productivity/higher mill availability

•   Reduction of roll inventory

•   Modest technological invest

•   Low capital and manufacturing costs

Advantages of PRETEX – Steel Sheet Surface Structure for Forming:

•   Low Friction Coefficient •   Building of closed Lubricant Pockets •   High amount of Closed Lubricant Pockets with equal Distribution

improves formability and reduces abrasion in forming tools. •   Customized surface structure/roughness/peak account

Advantages for Painting:

•   Perfect Stochastic Distribution (no Moiré – Effect) •   High Peak Count Values (Pc) together with higher Roughness Values •   Homogenous Peak Distribution •   Less Short Wave/Long Wave structures improve painting appearance

TOPOCROM structured Sheets: Trade Names à PRETEX® of Salzgitter AG and POSTEX® of POSCO

TOPOCROM® - PRETEX Surface Structure: Advantages for the automotive industry

Structure of the Presentation

Ø   TOPOCROM® - Electroplating Technology

Ø   Demands of the automotive industry on the surface structure of cold rolled sheet metal

Ø   Requirements of the steelmaking industry for texturing technology of working rolls for skin passing mills

Ø   PRETEX Surface Structure: Prospects ◄◄◄

PRETEX Surface Structure: Prospects

The automotive industry places increasing demands on painting appearance and processing properties of the delivered thin sheet metal. The TOPOCROM structure offers a high potential of optimization possibilities because of the independent customizability of the different structure parameters. In comparison to other texturing processes the TOPOCROM structure provides unique possibilities regarding the variety of structures. Therefore a steady further development of the surface structures by steelmakers is obligatory. To achieve this Salzgitter Flachstahl is linking process- and structure data. The most important milestones are: Ø   Production accompanied by automated 3D-measurements and

automated qualification of roll and sheet surfaces Ø   Development of process methods for TOPOCROM plating on the

basis of data mining Ø   Systematic generation of PRETEX structures on thin sheet metal

optimized for painting appearance and formability Ø   Cooperation with press and paint shops of leading automotive

manufacturers to adjust the results and support production-integration

PRETEX Surface Structure – Prospects: Measuring Data

Ø  Automated measurement of 27 surface-samples within 45 min

Ø  Autonomous recognition and evaluation of calottes Ø  Calculation of structure parameters by a mathematical alghorithm

PRETEX Surface Structure – Prospects: Database, Datamining

Linking of production data: Communication between Topocrom-Structure-Database and other production systems including surface inspection.

Datamining: Evaluation of structural parameters to minimize imprints caused by dirt adhesions on work rolls.

Laser

Optical Profile

Filter

Longwave (LW) 0,6-10mm

Shortwave (SW) 0,1-0,6mm

Substrat

ca.110 GE (bei 20°)

PRETEX Surface Structure – Prospects: Optimization for press and paint shop

Ø  Laboratory trials for better formability and paint appearance

Ø  Optimization of structure parameters in close

cooperation with automotive manufacturers Ø  Integration of Pretex-Technology into production

processes and creation of new products

TOPOCROM® – Texturing: Technology and Advantages

Thomas Routschek Salzgitter Flachstahl, Salzgitter (Germany)

Karl Müll TOPOCROM Systems AG, Weinfelden (Switzerland)

BAOSTEEL BAC 2013, Shanghai (China)