Muhamad Azuan Zaudin

Muhammad Afzal Ahmad

Muhammad Jamhuri Jamaludin

Mohd Azmir Abidin

Azman Senin

Ahmad Zakaria

A Study Of Distortion In Hot Stamping Process

UNIKL IPROM

28 August, 2013

<Unikl IPROM> Presentation at the ATC 2013

• Established in 2003 , the Institute of Product Design &

Manufacturing (IPROM) is one of the very specialized

engineering school under Universiti Kuala Lumpur.

• Currently the Institute offers five (5) degree programmes

leading to Bachelor of Engineering Technology (Hons )

in Product Design, Industrial Design, Tool and Die,

Manufacturing Systems and Business Management.

• Masters and PhD in Manufacturing (by research)

• Hyperworks modules are used in courses such as CAE

Driven Design, CAE in Sheet Metal Forming and Finite

Element Method

Background of Unikl Iprom

<Unikl IPROM> Presentation at the ATC 2013

A Study Of Distortion In Hot Stamping Process

• Objective of paper

To present the results of simulation analysis on distortion generated by

hot stamping process.

To compare the results with the actual automotive structural part.

+++

• Statement of problem

• Although distortion or springback is generally not a major issue in hot

stamping process. But it does frequently occur in long and slender part.

As such the ability to predict severity of this distortion before tool

manufacturing is of prime important to tool makers.

<Unikl IPROM> Presentation at the ATC 2013

METHODOLOGY

• Simulation Software : Hyperform 11.0

• Hot stamped part : Impact beam

• Mechanical and thermal parameters used ;

• Material : Boron Steel

• Blank temperature : 921°C

• Tool temperature : 10 °C

• Material model : Thermal Hill Orthotropic

• Material thickness : 1.2mm

• No of elements ;

• Blank : 8

• Tool : 0.5 - 30

• Element type

• Blank : Shell

• Tool : Rigid Shell

<Unikl IPROM> Presentation at the ATC 2013

METHODOLOGY

PART GEOMETRY

SPRINGBACK ANALYSIS

FORMABILITY ANALYSIS

COMPARE RESULTS WITH ACTUAL PART

<Unikl IPROM> Presentation at the ATC 2013

RESULTS

• Impact beam (Contour in Z displacement)

Actual part

Simulated part

+0.91mm

+0.77mm

-4.5mm

-5.2mm

<Unikl IPROM> Presentation at the ATC 2013

RESULTS (contd.)

• Predicted distortion by HF11.0

Reference geometry

Distorted part (curled downward)

<Unikl IPROM> Presentation at the ATC 2013

Benefits summary

• Hyperform 11.0 performs quite well in

formability analysis (prediction of cracks,

wrinkles, thickness distribution) of hot

stamping process but did badly in prediction of

distortion.

<Unikl IPROM> Presentation at the ATC 2013

Challenges faced and solutions presented

• Various errors displayed during the

simulation:

• Contact 7 or 21 error

• Defining part with varying thickness is

difficult.

• Stress strain file (*sta) sometimes not

readable hence springback analysis on

certain part cannot be done.

<Unikl IPROM> Presentation at the ATC 2013

Conclusion

• Distortion in hot stamped part is attributed primarily to

residual stresses resulted from elastic plastic strain as

well due to phase transformation process from austenite

to martensite during stamping and cooling.

• Therefore the springback module incorporated in HF11.0

may not be good enough for the prediction of

distortion(due to inavailability of phase transformation

module)

• Some of these features are expected in HF12.0

<Unikl IPROM> Presentation at the ATC 2013

Acknowledgements/Credits

• Special thanks to Miyazu Malaysia Sdn Bhd.

for providing the automotive parts and

technical data.

• UniKL-IPROM hot stamping group for trying

very hard to obtain a reasonably good result.