Investigation on tribological characteristics of boron steel 22MnB5–tool steel H13 tribopair at high temperature

2016 ◽  
Vol 231 (2) ◽  
pp. 165-175 ◽  
Author(s):  
Yanhong Mu ◽  
Baoyu Wang ◽  
Mingdong Huang ◽  
Jing Zhou ◽  
Xuetao Li
Keyword(s):  
High Temperature ◽  
Friction Coefficient ◽  
Tool Steel ◽  
Laser Scanning ◽  
Hot Stamping ◽  
High Strength ◽  
Tribological Characteristics ◽  
Confocal Laser ◽  
Boron Steel ◽  
Boron Steels

In the background that the quenchable boron steels have been widely used to manufacture body-in-white by hot stamping because of its ultra-high strength, the understanding of frictional characteristics of the boron steel–tool steel tribopair at high temperature should be deepened. In this work, the friction behaviors of the tool steel H13 against the boron steel 22MnB5 were investigated at different temperatures, sliding velocities, contact pressures, and lubrication conditions by ring-on-disc sliding testing. The tribological characteristics were analyzed through scanning electron microscope and confocal laser scanning. The results show the relationship between the friction coefficient and the hot stamping parameters well. The friction coefficient decreases remarkably with the increasing temperature and contact pressure, but sliding velocity has no noticeable influence on the friction coefficient. The wear mechanism also changes with different process parameters and the main mechanism is a combination of adhesive and abrasive wear. Furthermore, MoS2 lubricant can reduce the friction coefficient effectively and protect the die from severe wear.

Hot Stamping Processing Experiments of Quenchable Boron Steel

2008 ◽  
Vol 575-578 ◽  
pp. 299-304 ◽  
Author(s):  
Jun Bao ◽  
Zhong Wen Xing ◽  
Yu Ying Yang
Keyword(s):  
Heating Temperature ◽  
Hot Stamping ◽  
Cooling Water ◽  
High Strength ◽  
Processing Parameters ◽  
Boron Steel ◽  
Complicated Shape ◽  
Water Flow Velocity ◽  
Ultra High Strength Steel ◽  
Automotive Parts

The quenchable boron steel is a novel type of ultra high strength steel used for automotive parts so as to reduce the weight of the whole automobile. The hot stamping processing experiments for bending parts were studied. The influence of the hot stamping processing parameters, such as the heating temperature, the heat holding time and the cooling water flow velocity, on the mechanics properties and microstructure of the hot stamping parts is obtained. And then the optimal ranges of these parameters are determined, which provides a basis for the control of the hot stamping process applied in complicated shape parts’ production.

Numerical Simulation and Optimization of Cooling Ducts Layout in Hot Stamping Die

2012 ◽  
Vol 184-185 ◽  
pp. 333-336 ◽  
Author(s):  
Hui Xie ◽  
Ya Ke Chen
Keyword(s):  
Heat Transfer ◽  
Hot Stamping ◽  
Cooling Water ◽  
High Strength ◽  
Bulk Flow ◽  
Boron Steel ◽  
Press Hardening ◽  
Simulation And Optimization ◽  
Stamping Die ◽  
Cooling Ducts

Abstract. As an innovative process of manufacturing ultra high strength steel (UHSS), hot stamping or press hardening is a multi-physical coupling process with complex changes in thermal, mechanical and phase transformation. In this work, in order to study heat transfer from workpiece to upper & lower die and cooling water, a new approach, named Bulk Flow, is adopted to model the cooling ducts and to simulate heat transfer in hot stamping die. Not only can tool design, cooling duct layout and process parameters be studied and optimized to increase the cooling rate and to homogenize temperature distribution in workpiece, but also, the precision of hot stamping simulation be improved. The experimental results of boron steel components formed by the designed die show that the martensite is homogenous. It indicates the feasibility of the bulk flow method．

scholarly journals Research on the Re-Deformation Characteristics of Hot Stamping of Boron Steel Parts with Tailored Properties

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1136 ◽  
Author(s):  
Ling Kong ◽  
Yan Peng ◽  
Caiyi Liu
Keyword(s):  
Grain Boundaries ◽  
Initial Phase ◽  
Hot Stamping ◽  
High Strength ◽  
Boron Steel ◽  
Deformation Characteristics ◽  
Maximum Strain ◽  
Soft Zone ◽  
Local Misorientation

Traditional hot-stamping products have super-high strength, but their plasticity is usually low and their integrated mechanical properties are not excellent. Functionally graded property structures, a relatively novel configuration with a higher material utilization rate, have increasingly captured the attention of researchers. Hot stamping parts with tailored properties display the characteristics of local high strength and high plasticity, which can make up for the limitations of conventional hot stamping and optimize the crash safety performance of vehicles. This new idea provides a means of personalized control in the hot-stamping process. In this paper, a new strategy of local induction heating and press hardening was used for the hot stamping of boron steel parts with tailored properties, of which the microstructure from the hard zone to the soft zone shows a gradient distribution consisting of a martensite phase, multiphase and initial phase, with the hardness ranging from 550 HV to 180 HV. The re-deformation characteristics of hot stamping parts with tailored properties have been studied through the uniaxial tensile test, in cooperation with digital image correlation (DIC) and electron backscattered diffraction (EBSD) techniques. The experiments show that there are easily observable strain distribution characteristics in the re-deformation of hot stamping parts with tailored properties. In the process of tensile deformation, the initial phase zone takes the role of deformation and energy absorption, with the maximum strain before necking reaching 0.32. The local misorientation of this zone was high, and a large number of low angle grain boundaries were formed, while the proportion of small angle grain boundaries increased from 13.5% to 63.3%, and the average grain size decreased from 8.15 μm to 3.43 μm. Meanwhile, the martensite zone takes on the role of anti-collision protection, with a maximum strain of only 0.006, and its local misorientation is mostly unchanged. The re-deformation experimental results show that the hot stamping of boron steel parts with tailored properties meets the functional requirements of a hard zone for anti-collision and a soft zone for energy absorption, suitable for automobile safety parts.

scholarly journals Influence of lubrication, tool steel composition, and topography on the high temperature tribological behaviour of aluminium

Friction ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 155-168
Author(s):  
Justine Decrozant-Triquenaux ◽  
Leonardo Pelcastre ◽  
Braham Prakash ◽  
Jens Hardell
Keyword(s):  
High Temperature ◽  
Tool Steel ◽  
Aluminium Alloys ◽  
Friction And Wear ◽  
Weight Ratio ◽  
High Strength ◽  
Wear Behaviour ◽  
Tribological Behaviour ◽  
Material Transfer ◽  
The Stability

Abstract The use of high strength aluminium alloys, such as 6XXX and 7XXX series, is continuously increasing for automotive applications in view of their good strength-to-weight ratio. Their formability at room temperature is limited and they are thus often formed at high temperatures to enable production of complex geometries. Critical challenges during hot forming of aluminium are the occurrence of severe adhesion and material transfer onto the forming tools. This negatively affects the tool life and the quality of the produced parts. In general, the main mechanisms involved in the occurrence of material transfer of aluminium alloys at high temperature are still not clearly understood. Therefore, this study is focussed on understanding of the friction and wear behaviour during interaction of Al6016 alloy and three different tool steels in as-received and polished state. The tribotests were carried out under dry and lubricated conditions, with two distinct lubricants, using a reciprocating friction and wear tester. The worn surfaces were analysed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed a high dependence of friction and wear behaviour on the tool steel roughness as well as on the stability of the lubricant films. Tribolayers were found to develop in the contact zone and their capacity to improve the tribological behaviour is seen to be drastically impacted by the surface roughness of the tool steel. When the tribolayers failed, severe adhesion took place and led to high and unstable friction as well as material transfer to the tool steel.

Measurement and Analysis of Time-Temperature-Transformation Curves of Boron Steel 22MnB5

2010 ◽  
Vol 29-32 ◽  
pp. 484-489 ◽  
Author(s):  
Lian Fang He ◽  
Guo Qun Zhao ◽  
Hui Ping Li
Keyword(s):  
Phase Transformation ◽  
Hot Stamping ◽  
Expansion Method ◽  
Optical Microscope ◽  
Boron Steel ◽  
Forming Technology ◽  
Measurement And Analysis ◽  
Quenching Process ◽  
Temperature Transformation ◽  
Boron Steels

Hot stamping of quenchable boron steels is a new and complex forming technology integrating metal hot forming and quenching process. In order to gain the Time – Temperature - Transformation (TTT) curves of 22MnB5, the phase-transformation temperatures of boron steel 22MnB5 are measured by DIL 805A/D quenching and deformation dilatometer. According to the expansion curves of phase-transformation at some constant temperatures, the start and finish temperatures of phase-transformation are calculated by using the expansion method and the tangential method. The types of metallographic phases after phase-transformation are judged by the optical microscope and micro hardness. The TTT curves of 22MnB5 are drawn in terms of the results of testing and calculating.

High Temperature Heat Transfer During Hot Forming Die Quenching of Boron Steel

2013 ◽  
Author(s):  
Etienne Caron ◽  
Kyle J. Daun ◽  
Mary A. Wells
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling Rate ◽  
Hot Stamping ◽  
High Strength ◽  
Hot Forming ◽  
Boron Steel ◽  
Steel Blank ◽  
Die Quenching

Distributed mechanical properties can be obtained in ultra high strength steel parts formed via hot forming die quenching (HFDQ) by controlling the cooling rate and microstructure evolution during the quenching step. HFDQ experiments with variable cooling rates were conducted by quenching Usibor® 1500P boron steel blanks between dies pre-heated up to 600°C. The heat transfer coefficient (HTC) at the blank / die interface, which is used to determine the blank cooling rate, was evaluated via inverse heat conduction analysis. The HTC was found to increase with die temperature and stamping pressure. This heat transfer coefficient increase was attributed to macroscopic flattening of the boron steel blank as well as microscopic deformation of surface roughness peaks. At the end of the hot stamping process, the HTC reached a pressure-dependent steady-state value between 4320 and 7860 W/m2·K when the blank and die temperatures equalize.

Sign in / Sign up

Export Citation Format

Share Document