Prediction of Phase Transformation of Boron Steel Sheet during Hot Press Forming using Material Properties Modeler and DEFORMTM-HT

There has been a growing usage of high strength steels (HSS), particularly in automobile applications mainly as structural parts in view of their light weight and high strength properties. These materials are also being considered for dynamic applications. However, the multi-phase microstructure, which is at the base of the strengthening mechanisms in most of these steels, leads to unacceptably high stresses during forming and significant springback phenomena, thus making traditional sheet metal forming technologies unsuitable. To avoid the disadvantages, a new process method was introduced – Hot Press Forming. Hot press forming (HPF) process is a forming method which can provide various advantages such as excellent mechanical properties and formability, good weldability and little springback. Here, the experiment parameters which include locations of the cooling holes and the flow rate of the cooling water play an important role in the HPF process. In this paper, the Al-Si coated boron steel sheet was researched by heating it up to 930oC for 5 min and formed by a hydraulic press. In this study, microstructural evolutions and the associated mechanical properties were investigated in terms of the flow rates of the cooling water.

Download Full-text

Mechanical Property Degradation of Laser Welded Boron Steel Sheet in Hot Press Forming

Advanced Science Letters ◽

10.1166/asl.2012.3872 ◽

2012 ◽

Vol 13 (1) ◽

pp. 447-450 ◽

Cited By ~ 3

Author(s):

Daeyong Kim ◽

Ji Hoon Kim ◽

M. G. Lee ◽

Young Il Kim

Keyword(s):

Mechanical Property ◽

Steel Sheet ◽

Boron Steel ◽

Hot Press ◽

Press Forming ◽

Hot Press Forming

Download Full-text

Mechanical Characterization Behavior of Boron Steel Sheet in Hot Press Forming Process with Cooling System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.264-265.48 ◽

2011 ◽

Vol 264-265 ◽

pp. 48-53

Author(s):

S.H. An ◽

Ki Young Kwon ◽

Chung Gil Kang

Keyword(s):

Heat Transfer ◽

Cooling Rate ◽

Material Properties ◽

Cooling System ◽

Boron Steel ◽

Hot Press ◽

Forming Process ◽

Press Forming ◽

Hot Press Forming ◽

The Heat Transfer Coefficient

When cooling a boron sheet that has been heated to over 900 °C by hot press forming (HPF) process, the microstructure obtains a martensitic structure by controlling the cooling rate. HPF has advantages such as improvement in formability and material properties, and minimal springback of the formed material. The facts influenced by the cooling rate are determined by the heat transfer characteristics between the heated materials and the dies. In this study, controlling of the cooling rate is addressed by controlling the heat transfer coefficient of the material during the pressing process. This study demonstrates the material properties and microstructures of the formed material during the HPF process wherein cold dies are used to form the heated steel plate. This is achieved by varying the major forming conditions: the cooling rates, which is regarded as the most important process parameter.

Download Full-text

The Effect of Mechanical Property of Tailor Welding Blank and Hot Press Forming Process by the Different Anti-oxidation Coating Treatment on Boron-steel Sheet

Journal of the Korean Society for Heat Treatment ◽

10.12656/jksht.2012.25.6.283 ◽

2012 ◽

Vol 25 (6) ◽

pp. 283-291

Author(s):

Sang-Gweon Kim ◽

Ok-Dong Lim ◽

Jae-Hoon Lee

Keyword(s):

Mechanical Property ◽

Steel Sheet ◽

Boron Steel ◽

Hot Press ◽

Forming Process ◽

Press Forming ◽

Hot Press Forming

Download Full-text

Experimental Assessment of High Temperature Formability of Boron Steel Sheet Manufactured With a Spring Compound Bending Die

Journal of Engineering Materials and Technology ◽

10.1115/1.4006227 ◽

2012 ◽

Vol 134 (2) ◽

Cited By ~ 1

Author(s):

Yang Li ◽

Yong-Phil Jeon ◽

Chung-Gil Kang

Keyword(s):

Mechanical Properties ◽

Heating Temperature ◽

Boron Steel ◽

Hot Press ◽

Forming Process ◽

Steel Sheets ◽

Press Forming ◽

Bending Process ◽

Tension Testing ◽

Hot Press Forming

Bending behavior occurs in the hot press forming process, resulting in many cases of failure during forming. To address the problem of cracking and improve the formability and mechanical properties of boron steel sheets in the bending process, an experiment has been carried out by using a spring compound bending die. Also, a comparison has been made between the traditional U-bending die and the spring compound bending die with regard to formability. The influence of the parameters for hot press forming such as the heating temperature, punch speed, and die radii on the mechanical properties and microstructure was analyzed by tension testing and metallographic observations.

Download Full-text

Corrosion Assessment for Boron Steel Weldments Prepared by Overlap Welding and Successive Hot Press Forming Processes

Journal of Welding and Joining ◽

10.5781/jwj.2017.35.5.1 ◽

2017 ◽

Vol 35 (5) ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Minjung Kang ◽

Cheolhee Kim

Keyword(s):

Boron Steel ◽

Hot Press ◽

Press Forming ◽

Hot Press Forming ◽

Corrosion Assessment

Download Full-text

Hardness Prediction of Tailor Rolled Blank in Hot Press Forming Using Quench Factor Analysis

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.729.110 ◽

2017 ◽

Vol 729 ◽

pp. 110-114

Author(s):

Jae Hong Kim ◽

Dae Cheol Ko ◽

Byung Min Kim

Keyword(s):

Factor Analysis ◽

Fe Simulation ◽

Boron Steel ◽

Rear Side ◽

Cooling Curves ◽

Hot Press ◽

Tailor Rolled Blank ◽

Side Member ◽

Press Forming ◽

Hot Press Forming

This paper aims to predict the hardness of hot formed part for tailor rolled blank (TRB) by the FE-simulation coupled with quenching factor analysis (QFA). Dilatometry test of boron steel is performed at various range of cooling rates from 0.2 to 100°C/s using the dilatometer with forced air cooling system. The dilatometry test provides a hardness data according to cooling curves which are used to determine the material constants (K1~K5) of QFA and the time‒temperature‒property (TTP) diagram of boron steel. Then, FE‒simulation of hot press forming is conducted to predict the cooling curves of hot formed TRB part with a thickness combination of thicker 1.6mm and thinner 1.2mm which is called as rear side member of automotive component. The cooling curves of FE-simulation are applied to predict the hardness of hot formed rear side member using the QFA. Also, experiment of hot press forming is performed to verify the predicted results and to examine the effect of cooling curves on the hardness.

Download Full-text