Effect of selective laser heat treatment on geometrical variation in boron steel components: An experimental investigation

2020 ◽  
Vol 235 (1-2) ◽  
pp. 54-64
Author(s):  
Vaishak Ramesh Sagar ◽  
Kristina Wärmefjord ◽  
Rikard Söderberg
Keyword(s):  
Heat Treatment ◽  
High Strength ◽  
Boron Steel ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
Heat Treated ◽  
Geometrical Variation ◽  
And Performance ◽  
Boron Steels ◽  
Heating Direction

Selective laser heat treatment is a well-known process for its ability to produce tailor heat treated blanks (THTB). Specifically, ultra high strength boron steels with tailored material properties can be produced. However, this process generates unwanted distortion and influences geometrical variation. This in turn can affect functionality, aesthetics, and performance of the final product. Understanding the effects on geometrical variation in the final product or the assembly will enable in designing and producing geometry assured products. In this paper, boron steel blanks were selectively laser heat treated with a specific heat treatment pattern and laser heating direction sequence. These heat treated blanks were then cold formed. Further on, spot welding simulation of the cold formed parts was performed to assess the effect on geometrical variation at the assembly level. The results show that the effect of selective laser heat treatment on geometrical variation at part level propagates further to the assembly level. It implies that the effect on geometrical variation should be minimized at part level, when the blanks are laser heat treated. Hence, the sources that influence geometrical variation at part level when employing selective laser heat treatment are presented and discussed. The motivation and possibilities to minimize the effects in the early design concept stages is provided.

scholarly journals Geometrical Variation from Selective Laser Heat Treatment of Boron Steels

Procedia CIRP ◽  
2018 ◽  
Vol 75 ◽  
pp. 409-414 ◽  
Author(s):  
Vaishak Ramesh Sagar ◽  
Kristina Wärmefjord ◽  
Rikard Söderberg
Keyword(s):  
Heat Treatment ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
Geometrical Variation ◽  
Boron Steels

Influence of Selective Laser Heat Treatment Pattern Position on Geometrical Variation

2018 ◽  
Author(s):  
Vaishak Ramesh Sagar ◽  
Kristina Wärmefjord ◽  
Rikard Söderberg
Keyword(s):  
Heat Treatment ◽  
Material Properties ◽  
Treatment Pattern ◽  
Original Position ◽  
Boron Steel ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
Wide Range ◽  
Local Areas ◽  
Geometrical Variation

Selective laser heat treatment allows local modification of material properties and can have wide range of applications within the automotive industry. Enhanced formability and strength are possible to achieve. As the process involves selective heating, positioning of the heat treatment pattern in local areas is vital. Pattern positioning is often suggested based on the part design and forming aspects of the material to avoid failures during manufacturing. Along with improving material properties in desired local areas, the process also produces unwanted distortion in the material. Such effects on variation should be considered and minimized. In this paper, heat treatment pattern is offset from its original position and its effect on geometrical variation is investigated. Boron steel blanks are selectively laser heat treated with a specific heat treatment pattern and then stamped to desired shape. Two heat treatment pattern dimensions are examined. Variation at blank level and after stamping, and springback after stamping is observed. Results show that pattern offsetting leads to higher geometrical variation. Therefore, correct positioning of heat treatment pattern is important to minimize its effect on geometrical variation along with enhancing the material properties. Knowledge from this study will contribute to various stages of the geometrical assurance process.

Influence of Selective Laser Heat Treatment Pattern Position on Geometrical Variation

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Vaishak Ramesh Sagar ◽  
Kristina Wärmefjord ◽  
Rikard Söderberg
Keyword(s):  
Heat Treatment ◽  
Material Properties ◽  
Treatment Pattern ◽  
Boron Steel ◽  
Laser Heat Treatment ◽  
Cold Forming ◽  
Laser Heat ◽  
Wide Range ◽  
Local Areas ◽  
Geometrical Variation

Selective laser heat treatment allows local modification of material properties and can have a wide range of applications within the automotive industry. Enhanced formability and strength are possible to achieve. As the process involves selective heating, positioning of the heat treatment pattern in local areas is vital. Pattern positioning is often suggested based on the part design and forming aspects of the material to avoid failures during manufacturing. Along with improving material properties in desired local areas, the process also produces unwanted distortion in the material. Such effects on variation should be considered and minimized. In this paper, the heat treatment pattern is offset from its original position and its effect on geometrical variation is investigated. Boron steel blanks are selectively laser heat treated with a specific heat treatment pattern and then cold formed to the desired shape. Two heat treatment pattern dimensions are examined. Geometrical variation at the blank level and after cold forming, and springback after cold forming are observed. Results show that pattern offsetting increases the effect on geometrical variation. Therefore, correct positioning of the heat treatment pattern is important to minimize its effect on geometrical variation along with enhancement in the material properties. Knowledge from this study will contribute to various stages of the geometry assurance process.

The preparation and performance of grain size gradient TWIP steel fabricated by laser heat treatment

2019 ◽  
Vol 743 ◽  
pp. 294-300 ◽  
Author(s):  
Kun Wang ◽  
Aiping Wei ◽  
Zimu Shi ◽  
Xizhang Chen ◽  
Jixing Lin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Twip Steel ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
And Performance ◽  
Size Gradient

Formability of Ultrafine-Grained AA6016 Sheets Processed by Accumulative Roll Bonding

2012 ◽  
Vol 504-506 ◽  
pp. 575-580 ◽  
Author(s):  
Tina Hausöl ◽  
Christian W. Schmidt ◽  
Verena Maier ◽  
Wolfgang Böhm ◽  
Hung Nguyen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Laser Heat Treatment ◽  
Bending Tests ◽  
Roll Bonding ◽  
Laser Heat ◽  
Heat Treated ◽  
Ultrafine Grained ◽  
Ultrafine Grained Microstructure ◽  
Bending Behaviour

Aluminium alloy AA6016 was accumulative roll bonded up to eight cycles in order to produce an ultrafine-grained microstructure. The formability of these sheets was investigated by means of bending tests. Furthermore the influence of a local laser heat treatment at the bending edge is observed. The strength of the UFG samples is increased by a factor of around two compared to the conventionally grained T4 condition which also results in up to 50 % higher punch forces needed for bending of ARB processed samples. An anisotropic bending behaviour is observed. By applying a tailored laser heat treatment along the bending edge prior to the bending tests a local recrystallization and recovery at the deformation zone of the samples is achieved. Thus, ductility is increased locally whereby bending to an angle of 80° is possible with lower forming forces compared to the non-heat treated specimens. The results are compared to previous studies on mechanical properties and formability investigations of ARB processed AA6016.

scholarly journals Nanostructuring Behavior of NiCrBSi and CoCrWC Thermal Spray Coatings Formed by Temperature-Controlled Laser Heat Treatment

2020 ◽  
Vol 58 (4) ◽  
pp. 247-256 ◽  
Author(s):  
Eun-Joon Chun
Keyword(s):  
Heat Treatment ◽  
Thermal Spray ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
Laser Heat Treatment ◽  
Real Time Control ◽  
Continuous Casting Mold ◽  
Time Control ◽  
Laser Heat ◽  
Heat Treated

.For surface hardening of a continuous casting mold component, a thermal spray coating of NiCrBSi (Metco-16C) and CoCrWC (Stellite-1) was performed followed by laser heat treatment of the coatings. To support selective modification of the thermal spray coating, a metallurgically determined surface temperature was maintained during the laser heat treatment, by real-time control of the laser power. In other words, nonhomogeneities in the macrosegregation of certain alloying elements, and voids in the as-sprayed state, could be improved. The main microstructural features of the Metco-16C coating laser-heat-treated at 1423 K were nanosized (100–150 nm) Cr5B3, M7C3, and M23C6 precipitates with a lamellar structure of Ni (FCC) and Ni3Si as the matrix phase. Those of the laser heat-treated Stellite- 1 coating at 1473 K were fine (30–250 nm) precipitates of WC, M7C3, and M23C6 based on a Co (FCC) matrix. The results show that laser heat treatment at 1423 K increased the hardness of the Mecto-16C coating to 1115 HV from the as-sprayed state (754 HV), while treatment at 1473 K increased the hardness of the Stellite-1 coating from 680 HV to 860 HV.

scholarly journals Evaluation of Effectiveness of Heat Treatments in Boron Steel by Laser Thermography

2021 ◽  
Vol 8 (1) ◽  
pp. 8
Author(s):  
Giuseppe Dell’Avvocato ◽  
Davide Palumbo ◽  
Maria Emanuela Palmieri ◽  
Umberto Galietti
Keyword(s):  
Heat Treatment ◽  
Surface Modification ◽  
Heat Treatments ◽  
Boron Steel ◽  
Active Thermography ◽  
Heat Treated ◽  
Surface Laser ◽  
Boron Steels ◽  
Non Destructive

The applicability of active thermography as a non-destructive method to distinguish heat treated from not-treated boron steel has been investigated. While the usual hardness semi-destructive tests influence the inspected surface, laser thermography is capable of verifying the effectiveness of heat treatment in boron steel in a non-destructive way without any surface modification. The procedure has been verified on two plates of boron steels with different structures (100% ferritic–pearlitic and 100% martensitic).

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