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Effect of heat-treatment on the hardness and mechanical properties of Boron Alloyed Steel

Authors:
Mohammad Raffik bin Khiyon
Mohammad Raffik bin Khiyon
Mohammad Raffik bin Khiyon
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M. S. Salwani at Universiti Malaysia Pahang Al-Sultan Abdullah
M. S. Salwani
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Abstract and Figures

In an automotive industry, hot stamped, die quenched structural components have been widely used to provide extra protection against crash intrusion. Boron alloyed steel exhibit limited ductility, but it also promotes improvement in impact performance. This study analyzed the effect of cooling rate on the hardness and energy absorption. Self-quenched specimens were heated to 850°C and cooled in air of room temperature, water at room temperature and cold water. Vickers hardness test and tensile test was then carried out to analyze the effect of different quenching rate. Self-quenched specimens were compared to the properties of the die-quenched specimens obtained from commercial automobile body. Result shows that boron steel with the highest cooling rate has the highest value of hardness but low in strength.
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Available via license: CC BY 4.0
Content may be subject to copyright.
Effect of heat-treatment on the hardness and
mechanical properties of Boron Alloyed Steel
Mohammad Raffik bin Khiyon1, Salwani Mohd Salleh1,*
1Faculty of Mechanical Engineering, Universiti Malaysia Pahang (UMP), 26600 Pekan, Pahang,
Malaysia
Abstract. In an automotive industry, hot stamped, die quenched structural
components have been widely used to provide extra protection against
crash intrusion. Boron alloyed steel exhibit limited ductility, but it also
promotes improvement in impact performance. This study analyzed the
effect of cooling rate on the hardness and energy absorption. Self-
quenched specimens were heated to 850qC and cooled in air of room
temperature, water at room temperature and cold water. Vickers hardness
test and tensile test was then carried out to analyze the effect of different
quenching rate. Self-quenched specimens were compared to the properties
of the die-quenched specimens obtained from commercial automobile
body. Result shows that boron steel with the highest cooling rate has the
highest value of hardness but low in strength.
1 Introduction
Steel manufacturers produce alloy boron steels that have undergone heat treatment,
including quenching or quenching and tempering at low temperatures to attain high
resistance to dynamic loads [1]. The adding of boron significantly increases the
hardenability and strength of low and medium carbon steel was already observe in the year
1930s.
The demand in automotive industry to reduce the vehicle weight while considering the
safety have rapidly increase the manufacturing of lightweight body parts from ultrahigh-
strength steels (UHSS). The process of forming this ultrahigh-strength steel is limited by
low formability and considerable spring back. To overcome this problem, boron has been
used as an alloying element for alloy steel. It is a vital material that plays an important role
as it has strong and hard properties [2]. Thus, when the strength is increased, the size of the
steel can be decreased and the weight will become lighter.
The desired mechanical properties and microstructure suitable for the specific purpose
can be reached, by selecting the parameters of heat treatment of these steels [3,4]. This
would allow them to extend their range of applications. However, the different
* Corresponding author: salwani@ump.edu.my
DOI: 10.1051/
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© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative
Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).
microstructures can cause different mechanical properties, require careful decision making
to define the application of these steels in many states of heat treatment. Thus, this study
the effect of heat-treatment on the hardness and mechanical properties of boron alloyed
steel.
2 Experimental setup
2.1 Specimens
Specimens are made of boron alloyed steel. This boron alloy steel grade 22MnB5 belongs
to the product category of quenched and tempered steels, and features outstanding strength
after heat treatment. The materials strength is propagated by adding a small fraction of
boron to the carbon, manganese and chromium composition. Table 1 below shows the
chemical composition of boron alloyed steel 22MnB5 that has been used in this research.
Table 1. Chemical composition of 22MnB5.
Chemical Element Percentage (%)
Carbon, C
0.250
Silicon, Si
0.400
Manganese, Mn
1.350
Phosphorus, P
0.023
Sulphur, S
0.010
Aluminium, Al
0.080
Nitrogen, N
0.010
Chromium, Cr
0.250
Boron, B
0.004
Different types of specimens tested are notated as: Blanked specimens (specimen-B);
Die-quenched specimens (specimen-HPF), Blanked specimens that are heated and cooled at
Room Temperature (specimen-RT); Blanked specimens that are heated and cooled in room
temperature water (specimen-WRT); and Blanked specimens that are heated and cooled in
cold water (specimen-WC). A total of 9 specimens were used in this heat treatment. First,
all the specimen was heated in the furnace up to 900 qC for 2 hours. Secondly, the initial
temperature of the specimen was taken by using infrared thermometer (range -50 qC – 1150
qC). Then, three of the specimen was taken out and cooled at room temperature. Another
three specimens was taken out and cooled in water at room temperature (25 qC) for 5
seconds and the final temperature of the specimen was taken. Then, last three specimens
was taken out and cooled in cold water (5 qC) for 5 seconds and the final temperature of the
specimen was taken. The temperature was taken to calculate the cooling rate for each type
of quenching process in both type of water.
2.2 Experimental procedures
Vickers test was done based on the ASTM E384 to determine the hardness of each
specimen. Since the material is in form of sheet, which is used for hot stamping, it is
important to study the behaviour of the rolled sheet using tensile test. For the tensile testing,
boron steel plate were cut into dimension as specified in ASTM 08M. All of the specimens
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were tested subjected to three velocities of the top platen plate, 3 mm/min, 6mm/min and 9
mm/min.
3 Results and discussion
There are two types of testings that was conducted in this research which is the Hardness
Test (Vickers) and Tensile Test. Both test conducted based on the ASTM. Both tests consist
of control specimen of 22MnB5 with different type of treatment that has been done.
3.1 Hardness test result
Vickers Hardness test is carried out to obtain the hardness. Pyramid diamond indenter is
pressed at 7 points for an interval of 0.2 mm for each of specimen types. The graph for this
test were summarized in Figure 1 below.
Fig. 1. Vickers Hardness test result for (a) specimen-B (b) specimen-HPF (c) specimen
--RT
(d) specimen-WRT and (e) specimen-WC.
(a)
(b)
(c)
(d)
(e)
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Based on Fig. 1, the average Vikers Hardness for each of the specimens are: 192.96 HV
(specimen-B); 304.19 HV (specimen-HPF), 253.91 (specimen-RT); 272.4HV (specimen-
WRT); and 457.93HV (specimen-WC). The Vickers hardness test results for 22MnB5
shows that the highest value for hardness is for specimen-OWC that is and the lowest value
is for specimen-O. Specimen-O has the lowest Vickers Hardness value because the
microstructure for this steel contains a mixture of pearlite phase, ferrite and small amount
of carbide. It has no martensitic in the microstructure. For other types of 22MnB5, it has
martensitic in the microstructure because of the process of annealing. The hardness of the
steel depends on the amount of martensitic on it and it also depends on the grain size, the
smaller the grain size, the higher the value of hardness and strength. The size of the grain
size depends on the cooling rate of the specimen. The faster the cooling rates, the smaller
the size of the grain size. Specimen-OWC has the fastest cooling rate which is 122.6 qC/s.
The fine grain of the martensitic structure of these steels creates their characteristic features
of high toughness, strength.
3.2 Tensile test result
In this analysis, properties that are directly measured via a tensile test are ultimate tensile
strength, and Young's modulus. This tensile test was done based on ASTM E8/E8M – 13
which is the Standard Test Methods for Tension Testing of Metallic Materials. The reading
for tensile test was taken with three different velocities which is 3, 6 and 9 mm/min. The
graph for all results was summarized in Table 2
Based on all the results obtained, the best steel is 22MnB5 HPF. 22MnB5 HPF has good
Tensile Stress and good Young Modulus compare to other 22MnB5. For as-received
22MnB5 and 22MnB5 RT, it has good Young Modulus but poor Tensile Stress. For
22MnB5 WRT, it has good Tensile Stress but poor Young Modulus and for 22MnB5 CW it
has poor Tensile Stress and Young Modulus. Poor Young Modulus will make the steel
becomes less flexible and become more to brittle. Brittle materials cannot absorb the impact
applied on it and it will break easier. Poor Tensile Stress means that the steels are not strong
enough. Weak materials cannot hold the high Tensile Stress applied on it and it also will
break easier.
Table 2. Stress-strain curves and fractured specimens.
Specimen
typ
es
Fractured specimen
specimen-B
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specimen-
HPF
specimen-
RT
specimen-
WRT
specimen-
CW
Legend: 3 mm/min 6 mm/min 3 mm/min
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4 Conclusions
As conclusion, the heat treatment done to the 22MnB5 with different type of quenching
process has portrayed an encouraging result, particularly in the hardness of the 22MnB5.
The higher the cooling rate of the quenching, the smaller the size of the grain size. Hence, it
will increase the hardness of the steel. When the cooling rate is very high, it will increase
the strength of the steel but it will reduce the toughness and the ductility of the steel. Higher
cooling rate tends to make the steel become less flexible and more brittle.
The authors would like to thanks Universiti Malaysia Pahang for providing laboratory facilities and
financial assistance under project no. RDU1303114.
References
1. H. So, D. Fasmann, H. Hoffmann, R. Golle, M. Schaper, An investigation of the
blanking process of the quenchable boron alloyed steel 22MnB5 before and after hot
stamping process, Journal of Materials Processing Technology 212 (2012) 437– 449.
2. M. Naderi, V. Uthaisangsuk, U. Prahl, W. Bleck, A Numerical and Experimental
Investigation into Hot Stamping of Boron Alloyed Heat Treated Steels, steel research
int. 79 (2008) No. 2.
3. N. Aziz, S.N. Aqida, Optimization of quenching process in hot press forming of
22MnB5 steel for high strength properties for publication, Materials Science and
Engineering 50 (2013).
4. P. Hu, D. Shi, L. Ying, G. Shen, W. Liu, The finite element analysis of ductile damage
during hot stamping of 22MnB5 steel, Materials and Design 69 (2015) 141–152.
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Full-text available
  • Jan 2009
Hot stamping of steel sheets using water or nitrogen cooling media was studied on a laboratory scale. Sheets of grade 22MnB5 boron steels in three different thicknesses were investigated and the results of experimental hot stamping tests were considered. Microstructural analysis, linear and surface hardness profiling as well as tensile tests of formed samples were carried out. After hot stamping, mostly fully martensitic microstructures, which yield ultra high strength levels, were produced. It is concluded that die cooling media, i.e., water or nitro- gen, have a significant effect on material properties after hot stamping. Using liquid nitrogen as coolant in the punch instead of water in- creases yield strength by 50 to 65MPa. Moreover, the evolution of the temperature and force during the hot stamping process was simu- lated by using a coupled thermomechanical FEM program. The results of numerical simulation and experimental results are in good agreement.
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The finite element analysis of ductile damage during hot stamping of 22MnB5 steel
Article
  • Mar 2015
  • MATER DESIGN
This study deals with the finite element investigation of hot stamping of high strength steel. The main objective is to predict when and where the crack can appear in the work-piece during the hot stamping operation. A set of thermo-elastic-plastic constitutive equations coupled with material damage is presented in detail based on continuum damage mechanics. The damage parameters involved in the constitutive equations were determined from uniaxial tensile experimental data of 22MnB5 steel at a temperature range of 650-800 °C and strain rates of 0.01, 0.1, 1.0 s−1. Using the calibrated constitutive equations, a finite element program was developed based on dynamic explicit algorithm and applied to simulate the deformation process and ductile damage of 22MnB5 under hot stamping conditions. The capability of the program as a predictive tool has been evaluated by comparing experimental and calculated results of the hot stamping process of an automotive B-pillar. And the effects of blank holding force and friction on formability, damage evolution and punch force were analyzed.
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