Welcome to the All New AHSS Application Guidelines!

Welcome to the All New AHSS Application Guidelines!

The leading source for technical best practices on the forming and joining of Advanced High-Strength Steels (AHSS) for vehicle manufacture is released today by WorldAutoSteel, the automotive group of the World Steel Association. The AHSS Application Guidelines Version 7.0 is now online at ahssinsights.org in a searchable database, allowing users to pinpoint information critical to successful use of these amazingly capable steels. WorldAutoSteel members make these Guidelines freely available for use to the world’s automotive community.

“More and more automakers are turning to AHSS to balance the needs for crashworthiness, lighter weight and lower emissions, while still manufacturing cars that are affordable,” says George Coates, Technical Director, WorldAutoSteel. “The AHSS Application Guidelines provides critical knowledge that will help users adapt their manufacturing environment to these evolving steels and understand processes and technologies that lead to efficient vehicle structures.” AHSS constitute as much as 70 percent of the steel content in vehicle structures today, according to automaker reports.

New grades of steel that are profiled in Version 7.0 show dramatically increased strength while achieving breakthrough formability, enabling applications and geometries that previously were not attainable.

“Steel’s low primary production emissions, now coupled with efficient fabrication methods, as well as a strong global recycling and reuse infrastructure all create a solid foundation upon which to pursue vehicle carbon neutrality,” notes Cees ten Broek, Director, WorldAutoSteel. “These Guidelines contain knowledge gleaned from global research and experience, including significant investment of our members who are the designers and manufacturers of these steels.”

Editors and Authors Dr. Daniel Schaeffler, President Engineering Quality Solutions, Inc., for Metallurgy and Forming, and Menachem Kimchi, M.Sc., Assistant Professor – Practice, Materials Science and Engineering, Ohio State University, have drawn from the insights of WorldAutoSteel members companies, automotive OEMs and suppliers, and leading steel researchers and application experts. Together with their own research and field experience, the technical team have refreshed existing data and added a wealth of new information in this updated version.

The new database includes a host of new resources for automotive engineers, design and manufacturing personnel and students of automotive manufacturing, including:

  • Hundreds of pages of searchable articles that include nearly 1,000 citations of original technical research papers, providing a rich library for study.
  • Search tools and related posts fueled by thousands of industry-specific keywords that enable users to drill down to the information they need.
  • Information on the metallurgy and mechanics of AHSS grades.
  • An explanation of 3rd Gen AHSS and what makes these grades unique.
  • A primer on Press Hardened Steels, one of the most popular AHSS grades in today’s automotive structures.
  • Summaries of new research in resistance spot welding for joining AHSS of multiple grades and thicknesses.
  • New information on modelling resistance spot welding.
  • An expanded solid state welding section.
  • New information on RSW joining of dissimilar steels as well as dissimilar materials.
  • Articles written by subject-matter experts and product manufacturers.
  • Integration of the popular AHSS Insights technical blog.

The new online format enables consistent annual updates as new mastery of AHSS’s unique microstructures is gained, new technology and grades are developed, and data is gathered.  Be sure to subscribe to receive regular updates and blogs that represent a world of experience as the database evolves.

You’re right where you need to be to start exploring the database.  Click Tutorials from the top menu to get a tour on how the site works so you can make the best of your experience.  Come back often–we’re available 24/7 anywhere in the world, no download needed!

Microstructural Effects of Adding Colloidal Graphite to Al-Si-Coated PHS

Microstructural Effects of Adding Colloidal Graphite to Al-Si-Coated PHS

Optimizing weld morphology and mechanical properties of

laser welded Al-Si coated 22MnB5 by surface application of

colloidal graphite

 

Researchers at University of Waterloo discovered the microstructural effects of adding colloidal graphite to Al-Si coated 22MnB5 Press Hardened Steel.K-51 Laser welds were made on 1.5 mm thick Al-Si coated 22MnB5 PHS perpendicular to the rolling direction. Pure colloidal graphite suspended in isopropanol base was applied to the area being welded and the resulting graphite coating after evaporation ranged from 5 µm to 130 μm for testing. Parameters used for the weld are: 4kW power, 6m/min welding speed, beam diameter of 0.3 mm, and laser defocus of 6mm. Samples were then hot stamped by heating for 6 min to 930 ᵒC in a furnace and then water quenched at a cooling rate greater than 30 ᵒC/s.

Al-Si coating is excellent at preventing oxidation and decarburization of high strength steel at elevated temperatures. However, during welding there is diffusion of Al into the fusion zone which stabilizes ferrite at elevated temperature reducing the strength of the welded joint. Colloidal graphite coating decreases the Al content and increases C content of the fusion zone. As shown in Figure 1, The mechanism for reduction in Al content is due the graphite coating acting as an insulator to the Al-Si coating which then causes an ejection of the molten Al-Si coating from the surface. Figure 2 displays a proportional reduction of Al in the fusion zone with increasing graphite coating thickness up to 40 μm where after the reduction in Al is minimal. This is attributed to the initial reduction of Al being caused by the ejection of the molten Al-Si from underneath the graphite coating. Graphite coating greater than 40 µm does not aid in additional ejection of Al-Si and the Al-Si coating already diluted in the weld pool will not be removed.

Figure 1: Al-Si ejection mechanism.K-51

Figure 1: Al-Si ejection mechanism.K-51

 

Figure 2: Al and C content in weld with increasing graphite thickness

Figure 2: Al and C content in weld with increasing graphite thickness.K-51

 

 

Summary

Ferrite concentration in the fusion zone was reduced from approx. 40% with no graphite coating to approx. 2% with 130 μm graphite coating thickness (Figure 3). The increase in C content and reduction in Al content resulted in an increase in austenite being stabilized at elevated temperature rather than ferrite and therefore a larger percentage of martensite results after hot stamping. The average fusion zone hardness increased from 320 HV with no coating to 540 HV with 130 μm coating thickness (Figure 4). The weld strength of the sample with no graphite coating was 1249±15MPa whereas the weld strength with a coating of 130 µm was 1561±7MPa which matches the base metal (Figure 5). With an increase in graphite coating thickness there is an increase in weld strength that can eventually match the base metal strength.

Figure 3: Ferrite concentration in weld.K-51

Figure 3: Ferrite concentration in weld.K-51

 

Figure 4: Fusion Zone Hardness vs. Graphite Thickness.K-51

Figure 4: Fusion Zone Hardness vs. Graphite Thickness.K-51

 

 

Figure 5: Weld strength vs. Graphite Thickness.K-51

Figure 5: Weld strength vs. Graphite Thickness.K-51

 

 

Steel Grades

Steel Grades

Steel Grades

See the brief Tutorial on using the Steel Grades search.

TitleTagsCategoriestags_hfiltercategories_hfilter
Martensite, , , , , , , , , , , 1stGen AHSS, AHSS, Steel Grades1stgen-steel ahss astm-a980m cold-stamping mart martensite martensite-metallurgy microstructural-components microstructure ms sae-j2745 vda-239-1001stgen-ahss ahss steel-grades metallurgy
Press Hardened Steels, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1stGen AHSS, AHSS, Press Hardened Steels, Steel Grades1stgen-steel 3rd-gen ahss alsi as-coating bake-hardenability boron-steel critical-cooling-rate direct-press-hardening e-billur hot-forming hot-press-forming hot-stamped-boron hot-stamping indirect-press-hardening martensite medium-mn phs phs-grades-over-1500-mpa phs-grades-with-tensile-strength-approximately-1500-mpa pqs-grades-with-high-elongation pre-cooled-direct-process press-hardening press-hardening-steels press-quenched-steel quenching stainless vda-239-500 zn-coated-phs1stgen-ahss ahss press-hardened-steels steel-grades metallurgy forming
Defining Steels, , , , , , , , , , , , , , , , , , , Metallurgy3rd-gen 3rd-generation ahss banana-diagram bubble-diagram defining-ahss defining-uhss football-diagram global-formability-diagram hance-diagram local-formability local-global-formability-map microstructural-components microstructure nomenclature syntax tensile terminology uhss yieldmetallurgy
Dual Phase, , , , , , , , , , , , , , , 1stGen AHSS, AHSS, Steel Grades1stgen-steel ahss astm-a1088 bake-hardening-effect dp dual-phase en-10338 ferrite jfs-a2001 jis-g3135 martensite microstructure sae-j2745 strain-hardening-exponent vda-239-100 work-hardening1stgen-ahss ahss steel-grades metallurgy
Transformation Induced Plasticity (TRIP), , , , , , , , , , , , , , , , , , 1stGen AHSS, 3rdGen AHSS, AHSS, Steel Grades1stgen-steel 3rd-generation ahss astm-a1088 bainite en-10338 ferrite jfs-a2001 martensite microstructure retained-austenite sae-j2745 strain-hardening-exponent transformation-induced-plasticity trip trip-effect trip-metallurgy vda-239-100 work-hardening1stgen-ahss 3rdgen-ahss ahss steel-grades metallurgy
Complex Phase, , , , , , , , , , , , , , , , , 1stGen AHSS, AHSS, Steel Grades1stgen-steel ahss astm-a1088 bainite bendability bending complex-phase cp en-10338 ferrite local-formability martensite microalloy microstructural-components microstructure precipitation-strengthening retained-austenite vda-239-1001stgen-ahss ahss steel-grades metallurgy
Ferrite-Bainite, , , , , , , , , , , , , , , , , , , 1stGen AHSS, AHSS, Steel Grades1stgen-steel ahss bainite cut-edge-stretching edge-stretchability en-10338 fb ferrite ferrite-bainite hhe hole-expansion hole-extrusion hole-flanging hot-rolled-steel jfs-a2001 microstructural-components microstructure stretchability stretching vda-239-1001stgen-ahss ahss steel-grades metallurgy
Ultra-Low Carbon (DDS – EDDS), , , , , , , , , , , Lower Strength Steels, Steel Gradesdds deep-drawing-steel edds extra-deep-drawing-steel ferrite ferrite-ultra-low-carbon-mild-steel microstructure mild-steel ulc ultra-low-carbon vacuum-degassed vd-iflower-strength-steels steel-grades metallurgy
3rd Generation Steels, , , , , , , , , , , , , , , , , , , , , , 3rdGen AHSS, AHSS, Steel Grades3rd-gen advanced-high-strength-steels ahss carbide-free-bainite cfb ch complex-phase-high-ductility cp-hd dh downgauging dp-hd dual-phase-high-ductility high-ductility intercritical-anneal manganese medium-mn overaging qp quench-and-partition tbf third-generation trip-assisted-bainitic-ferrite trip-effect3rdgen-ahss ahss steel-grades metallurgy
Carbon-Manganese (CMn), , , , , , , , , , , , Conventional HSS, Steel Gradesastm-a1008m c-mn carbon carbon-and-manganese carbon-manganese cmn conventional-high-strength-steel high-strength-steel jfs-a2001 jis-g3135 manganese structural-steel yield-strengthconventional-h-s-s steel-grades metallurgy
High Strength Low Alloy Steel, , , , , , , , , , , , , , , Conventional HSS, Steel Gradesastm astm-a1008m c-mn carbon-manganese cmn conventional-high-strength-steel en-10268 high-strength-low-alloy hsla jfs-a2001 jis-g3135 la microalloy precipitation-strengthening vda-239-100 yield-strengthconventional-h-s-s steel-grades metallurgy
Mild Steels, , , , , , , , , , , , , , , , Lower Strength Steels, Steel Gradesastm-a1008m dq dqak dqsk draw-quality-steel drawing-steel ds en-10130 ferrite jfs-a2001 jis-g3141 low-carbon microstructure mild-steel ulc ultra-low-carbon vda-239-100lower-strength-steels steel-grades metallurgy
Interstitial-Free High Strength, , , , , , , , , , Conventional HSS, Steel Gradesedds en-10268 if if-hs if-rephos interstitial-free-high-strength jfs-a2001 rephosphorized ulc vd-if vda-239-100conventional-h-s-s steel-grades metallurgy
Bake Hardenable, , , , , , , , , , , , , , , , , , , , AHSS, Conventional HSS, Steel Gradesastm-a1008m bake-hardenability bake-hardenable bake-hardening bake-hardening-effect baking-index bh bh-effect bhi carbon dent dislocations en10268 jfs-a2001 jis-g3135 microstructural-components paint-bake sae-j2575 strain-aging vda239-100 work-hardeningahss conventional-h-s-s steel-grades metallurgy
Twinning Induced Plasticity, , , , , , , , , , , , 2ndGen AHSS, AHSS, Steel Grades2nd-gen ahss dynamic-strain-aging fe-mn manganese microstructure plc-effect portevin-lechatelier-effect strain-rate-sensitivity stretch-formability twinning-induced-plasticity twip twip4eu2ndgen-ahss ahss steel-grades metallurgy