Note: Descriptions are shown in the official language in which they were submitted.
CA 02941276 2016-08-31
HIGH-STRENGTH BOLTING STEEL AND PREPARATION METHOD THEREFOR
100011 This application claims the benefit of priority to Chinese Patent
Application No.
201410091577.8, titled "HIGH STRENGTH BOLTING STEEL AND PREPARING
.. METHOD THEREOF", filed with the Chinese State Intellectual Property Office
on March 13,
2014.
FIELD
[0002] The present application relates to the field of metal, and in
particular to a high
strength bolting steel and a preparing method for the high strength bolting
steel.
BACKGROUND
[0003] In recent years, strong wind disasters, such as typhoon, frequently
attack the
southeast costal areas of China, causing damage to a number of electric
transmission and
transformation equipments and severely affecting a safe operation of a power
grid. Since the
southeast costal areas are developed areas of China and an electric load is
concentrated there,
the strong wind disasters often cause inestimable social damage and economical
loss for the
local areas. A high voltage power arrester in a substation is an important
device for power
supplying of a power system, which has a relatively low inherent frequency,
and a part of the
.. inherent frequency at low level is close to a main frequency range of a
strong fluctuating wind,
such as typhoon. The device will vibrate due to the strong fluctuating wind,
causing stress
concentration in different positions. In the case that the device resonates
due to the motivation,
the stress concentration areas of the device will rupture and fail.
[0004] Bolts of the power arrester device are generally arranged in the stress
concentration
areas of the device for supporting, fixing and connecting. In the case that
the vibrations
caused by wind causes stress concentration in the device, the bolts are apt to
distort when
suffering pulling stress and bending stress. Further, due to the supporting by
the bolts, upper
porcelain knobs will distort due to the distortion of the bolts, thereby
causing failure of the
whole device in the strong wind.
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English translation of PCT/CN2014/081896
OP1614-09-0442
[0005] In recent years, it is found by practice that adding RE (rare earth)
elements to an
alloy steel can efficiently improve a mechanical property of the alloy steel
and improve
various performance indexes of the material in different degrees. The
performances of the
material can be optimized by separately preparing the RE elements and the
alloy steel, and
mixing the RE elements with the alloy steel. Thus, currently, it is of great
importance to
optimize the components and improve performances of the bolting alloy steel
dedicated for
the arrester device in the wind resistance field of the power arrester.
SUMMARY
[0006] An object of the present application is to provide a high strength and
plastic bolting
steel and a preparation method for making the high strength and plastic
bolting steel.
[0007] In view of the above, a high strength belting steel is provided
according to the
present application, which includes:
RE 0.05w0/0-0.5wt%;
C 0.3510%-0.45wt%;
Cr 1.2wtcY0-1.8wt%;
Si 0.17wt%-0.37wt%;
Mo 0.4wt%-0.8wt%;
V 0.2wt%-0.4wt%;
Nb 0-0.005wt%;
with remainder being Fe,
where the RE is at least one of La and Ce.
[0008] Preferably, a content of the RE is 0.10wt%-0.48wt%.
[0009] Preferably, a content of the Mo is 0.48wt%-0.72wt%.
[0010] Preferably, a content of the Si is 0.20wt%-0.32wt%.
[0011] Preferably, a content of the Nb is 0.002wt%-0.0048wt%.
[0012] A method for preparing the high strength bolting steel is further
provided according
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to the present application, which includes:
step 1) casting a bolting steel ingot containing: rare earth 0.05wt%-0.5wt%,
carbon
0.35wt%-0.45wt%, chromium 1.2wt%-1.8wt%, silicon 0.17wt%-0.37wt%, molybdenum
0.4wt%-0.8wt%, vanadium 0.2wt%-0.4wt%, niobium 0-0.005wt%, with remainder
being Fe,
where the rare earth is at least one of lanthanum and cerium;
step 2) forging the bolting steel ingot and annealing the forged bolting steel
ingot;
step 3) quenching the bolting steel ingot obtained in step 2) and tempering
the quenched
bolting steel to obtain a high strength bolting steel.
100131 Preferably, step 1) may include:
preparing a raw material containing: the rare earth 0.05wt%-0.5wt%, the carbon
0.35wt%-0.45wt%, the chromium 1.2wt%-1.8wt%, the silicon 0.17wt%-0.37wt%, the
molybdenum 0.4wt%-0.8wt%. the vanadium 0.2wt%-0.4wt%, the niobium 0-0.005wt%
with remainder being the Fe, where the rare earth is at least one of the
lanthanum and the
cerium;
smelting, based on contents of the raw material, the carbon, the chromium, the
silicon,
the molybdenum, the vanadium, the niobium and the Fe for 40mins-45mins at 1500
C to
1600 C, and preserving heat for 15mins-25mins to obtain an initial bolting
steel ingot:
re-smelting the initial bolting steel ingot, adding at least one of the
lanthanum and the
cerium, and casting into a bolting steel ingot.
[0014] Preferably, a temperature of the annealing is 650 C to 700 C, and the
duration of
heat preservation for the annealing is 2-3 hours.
[0015] Preferably, a temperature of the quenching is 800 C to 900 C, and the
duration of
heat preservation for the quenching is 1 2 hours.
[0016] Preferably, a temperature of the tempering is 500 C to 600 C, and the
duration of
heat preservation for the tempering is 1-2 hours.
[001-1 The high strength bolting steel is provided according to the present
application,
which includes: rare earth 0.05wt%-0.5wt%, carbon 0.35%-0.45wt%, chromium
1.2w0/0-1.8wt%, silicon 0.17w0/0-0.37wt%, molybdenum 0.4wt%-0.8wt%, vanadium
0.2wt%-0.4wt%, niobium 0-0.005wt%, with remainder being the Fe. In the present
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application, the lanthanum or the cerium added into the bolting steel can
efficiently refine
grain structures of the bolting steel, reduce the content of hydrogen and
diffusion and
permeation of hydrogen in the steel, reduce grain boundary segregation of the
harmful
elements. and improve strength of the steel: the added chromium can
efficiently improve the
antioxidation and anticorrosion capability of the material, and improve the
hardenability of
the material to increase the strength; and the added molybdenum can strengthen
the grain
boundary of the material, improve the hardenability of the material, increase
the tempering
stability and improve the toughness of the material. The carbon, vanadium,
niobium and Fe
are further added into the bolting steel according to the present application,
which interact and
cooperate with each other, such that the bolting steel has high strength and
plasticity, thereby
providing strong supporting, fixing and connecting for the power arrester
device, efficiently
resisting stress concentration and deviation behavior of the arrester device
due to a strong
wind, and protecting a safe operation of the device.
[0018] A method for preparing the high strength bolting steel is further
provided according
to the present application. During a process of preparing the bolting steel,
in the present
application, the bolting steel ingot is prepared firstly, and then the
prepared bolting steel ingot
is forged, such that grains of the bolting steel ingot are broken sufficiently
to obtain structures
with fine and uniform grains; the forged bolting steel ingot is annealed to
eliminate stress
generated during the forging process; and lastly the annealed bolting steel
ingot is quenched
and tempered, thereby obtaining martensite structures and a part of austenite
structures having
fine and uniform internal grains, and efficiently improving the strength and
plasticity of the
material.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0019] Hereinafter technical solutions of embodiments of the present
application are
described in detail. Apparently, the descried embodiments are only some rather
than all of the
embodiments of the present application. Any other embodiments obtained based
on the
embodiments of the present application by those skilled in the art without any
creative work
fall within the scope of protection of the present application.
[0020] According to an embodiment of the present application, a high strength
bolting steel
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English translation of PCT/CN2014/081896
OP1614-09-0442
is provided, which includes:
RE 0.05w0/0-0.5wt%;
0.35wt%-0.45wt%;
Cr 1.2wt%-1.8wt%;
Si 0.17wt%-0.37wt%;
Mo 0.4wV/0-0.8wt%;
V 0.2wt%-0.4wt%;
Nb 0-0.005wt%;
with remainder being Fe,
where the RE is at least one of La and Ce.
[0021] Lanthanum (La) and Cerium (Ce) each are RE elements. In the present
application,
La, Ce or a mixture of La and Ce is added into the bolting steel, and La or
Ce, which, as an
active element, can refine grain structures of the bolting steel efficiently,
thereby reducing a
content of hydrogen and diffusion and permeation of hydrogen in the steel,
decreasing grain
boundary segregation of hydrogen, sulphur and other harmful elements, and
improving the
strength, stiffness and plasticity of the steel. In the present application, a
content of La, Ce or
the mixture of La and Ce is 0.05wt%-0.5wt%. In this range, martensite and
austenite
structures increase obviously in the steel, and mechanical properties of the
steel are optimized.
In the case that the content of La, Ce or the mixutre of La and Ce is less
than 0.05wt%, the
generated effect is limited due to a less content, thereby influencing wind
resistance
performance of the material. In the case that the content of La, Ce and the
mixture of La and
Ce exceeds 0.5%, metal inclusions containing La, Ce or the mixture of La and
Ce enlarge and
increase in the material structure, and the material performance is
influenced, thereby causing
that a wind resistance requirement of the power arrester can not be met
gradually. The content
of La, Ce or the mixture of La and Ce is preferably in a range of 0.08wt%-
0.5wt%, more
preferably in a range of 0.10wV/0-0.48wt%, most preferably in a range of
0.12wt%-0.40wt%,
and most preferably in a range of 0.25wt%-0.35wt%.
[0022] Carbon (C), as an added element in the present application, can improve
the strength,
hardness and hardenability of the material. In the case that a content of C is
less than 0.35wt%,
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English translation of PCT/CN2014/081896
OP1614-09-0442
the bolting steel has good toughness and plasticity, but the strength,
hardness and
hardenability of the steel will be limited to a certain degree. In the case
that the content of C is
greater than 0.45w1%, the toughness and plasticity of the material is reduced
significantly, and
brittle fracture will occur easily. Thus, the content of C should be in a
range of
0.35wt%-0.45wt%. The content of C is preferably in a range of 0.37wt%-
0.42wV/o, and more
preferably in a range of 0.35wt%-0.40wt%.
[0023] Chromium (Cr) is added to the bolting steel, thereby efficiently
improving
antioxidation and anticorrosion capability of the material, and improving the
hardenability of
the material to increase the strength of the material. In the case that a
content of Cr is less than
1.2wt%, the above effect is difficult to be achieved; or in the case that the
content of Cr is
higher than I .8wt%, the toughness of the material will be reduced, thus the
content of Cr
should be in a range of 1.2wV/0-1.8wt%. The content of Cr is preferably in a
range of
1.3wt%-1.6wt%, and more preferably in a range of 1.4wt%-1.55wt%.
[0024] Silicon (Si) is a good deoxidizer for the material, and Si is added
into the bolting
steel, thereby improving strength of a solid solution of the bolting steel,
which is beneficial to
increase tempering stability of the material. In the case that a content of
silicon is higher than
0.37wt%, plasticity of the material will be reduced, or in the case that the
content of silicon is
less than 0.17wt%, the function of the deoxidizer and solid solution
strengthening of silicon
will be weakened. Thus, the best effect can be achieved only when the content
of silicon is in
a range of 0.17wt%-0.37wt%. The content of silicon is preferably in a range of
0.20wt%-0.32wt%, more preferably in a range of 0.23w0/0-0.30wt%, and most
preferably in
a range of 0.25wt%-0.28wt%.
[0025] Molybdenum (Mo) can strengthen grain boundary of the material, improve
hardenability of the material, increase temping stability and improve
toughness of the material.
In the case that a content of molybdenum is less than 0.4wt%, the above effect
is difficult to
be achieved; or in the case that the content of Mo is higher than 0.8wt%, a
cost of the bolting
steel is increased and the optimal economy can not be realized. Thus, a good
effect can be
achieved only when the content of molybdenum in the bolting steel is in a
range of
0.4wt%-0.8wt%. The content of Mo is preferably in a range of 0.48wt%-0.72wt%,
more
preferably in a range of 0.54wt%-0.68wt%, and most preferably in a range of
0.60wt%-0.65wt%.
- 6 -
[0026] Vanadium (V) can efficiently restrain diffusion of hydrogen, refine
grains, and
improve a mechanical property of the material. In the case that a content of V
is less than
0.2wt%, the above effect is difficult to be achieved; or in the case that the
content of V is
higher than 0.4wt%, the beneficial effect to the material structure will not
be improved but the
mechanical property of the material will be influenced as the content
increases. Thus, the
content of vanadium should be in a range of 0.2wt%-0.4wt%. The content of
vanadium is
preferably in a range of 0.25wt%-0.38vvt%, more preferably in a range of
0.28wt%-0.35wt%,
and most preferably in a range of 0.30wt /0-0.32wt%.
[0027] Niobium (Nb) can improve toughness of the material and refine
grain structures
efficiently. Niobium is a trace element contained in the material. In the case
that a content of
niobium is too high, the above effect can not be achieved, and the economy
will be influenced
greatly. Thus, the content of niobium should be in a range of 0-0.005wt%. The
content of
niobium is preferably in a range of 0.002wt%-0.0048wt%, and more preferably in
a range of
0.0035wt%-0.0040wt%.
[0028] "I he high strength bolting steel provided according to the present
application
includes: rare earth 0.05wV/0-0.5wV/0, carbon 0.35wt%-0.45wt%, chromium
1.2wt%-1.8wt%, silicon 0.17wt%-0.37wt%, molybdenum 0.4wt%-0.8wt%, vanadium
0.2wt%-0.4wt%, niobium 0-0.005wt%, with remainder being Fe, wherein the rare
earth is at
least one of lanthanum and cerium. In the bolting steel according to the
present application,
the added active element lanthanum and cerium can efficiently refine grain
structures of the
bolting steel, reduce the content of hydrogen and diffusion and permeation of
hydrogen in the
steel, reduce grain boundary segregation of the harmful elements, and improve
strength of the
steel. The added chromium can efficiently improve the antioxidation and
anticorrosion
capability of the material, arid improve the hardenability of the material to
increase the
strength. The added Mo can strengthen the grain boundary of the material,
improve the
hardenability of the material, increase the tempering stability and improve
the toughness of
the material. Carbon, vanadium, niobium and Fe are further added into the
bolting steel
according to the present application, which interact and cooperate with each
other, such that
the bolting steel has high strength and plasticity.
[0029] According to the present application, a method for preparing the
bolting steel is
further provided, which includes:
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step 1) casting a bolting steel ingot containing: rare earth 0.05wt%-0.5wt%,
carbon
0.35wt%-0.45wt%, chromium 1.2wt%-1.8wt%, silicon 0.17wt%-0.37wt%, molybdenum
0.4wt /0-0.8wt%, vanadium 0.2w0/0-0.4wt%, niobium 0-0.005wt%, with remainder
being Fe,
where rare earth is at least one of lanthanum and cerium;
step 2) forging the bolting steel ingot and annealing the forged bolting steel
ingot;
step 3) quenching the bolting steel ingot obtained in step 2) and tempering
the
quenched bolting steel to obtain a high strength bolting steel.
[0030] During a process of preparing the bolting steel, in the present
application, the
bolting steel ingot is cast firstly, and then the prepared bolting steel ingot
is forged, such that
internal structures of the bolting steel ingot are broken sufficiently; the
annealing is performed
to eliminate residual stress generated during the forging process, so as to
obtain uniform and
fine internal grains; and finally the annealed bolting steel is quenched and
tempered, which
obtains martensite structures and a part of austenite structures having
uniform and fine
internal grains, thereby improving the strength and plasticity of the bolting
steel.
[0031] According to the present application, during the process of
preparing the bolting
steel, firstly the bolting steel ingot is prepared, and rare earth elements
lanthanum, cerium or a
mixture of lanthanum and cerium is added into the bolting steel. Lanthanum and
cerium are
active elements, and lanthanum and cerium may be consumed in the case that
lanthanum and
cerium are added earlier during the forging process, Thus in the present
application,
preferably the active elements lanthanum and cerium are added later.
Preferably, the bolting
steel ingot is prepared as follows:
preparing a raw material containing: rare earth 0.05wt%-0.5wt%, carbon
0.35wt%-0.45wt%, chromium 1.2wt%-1.8vvt%, silicon 0.17wt%-0.37wt%, molybdenum
0.4wt%-0.8wt%, vanadium 0.2wt%-0.4wt%, niobium 0-0.005wt%, with remainder
being Fe,
where rare earth is at least one of lanthanum and cerium;
smelting, based on contents of the raw material, carbon, chromium, silicon,
molybdenum, vanadium, niobium and Fe for 40mins-45mins at 1500 C to 1600 C,
and
preserving heat for 15mins-25mins to obtain an initial bolting steel ingot;
re-smelting the initial bolting steel ingot, adding lanthanum, cerium or a
mixture of
lanthanum and cerium and casting into a bolting steel ingot.
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100321 During the process of preparing the bolting steel ingot, the
smelting is
performed by ways well-known for those skilled in the art, and preferably the
smelting is
performed in a vacuum induction furnace.
[0033] After the bolting steel ingot is prepared, in the present
application, the bolting
steel ingot is forged, so as to eliminate structure defect generated during
the casting process
and break big grains in the bolting steel ingot sufficiently, thereby
obtaining fine internal
grains. The forging is performed by ways well-known for those skilled in the
art. The steel
ingot is hot-rolled at 1150 C to obtain a hot-rolled bar, then the hot-rolled
bar is forged within
a range of 900 C to 1030 C. That is, the bolting steel is hot formed on a
horizontal forging
machine, such that a metal flow line is continuous along components, and a
fiber flow line is
complete. The forged bolting steel is cooled slowly and then annealed. The
annealing can
eliminate residual stress generated in the forging process, which prepares for
the subsequent
heat processing. The annealing is preferably performed at a temperature of 650
C to 700 C,
and the duration of heat preservation for the annealing is preferably 2-3
hours.
[0034] According to the present application, after the bolting steel is
annealed, the
bolting steel is quenched. The quenching is preferably performed at a
temperature of 800 C
to 900 C, and the duration of heat preservation for the quenching is
preferably 1-2 hours.
Finally the quenched bolting steel ingot is tempered, the tempering is
preferably performed at
a temperature of 500 C to 600 C, and the duration of the tempering is
preferably 1-2 hours.
In the present application, after the quenching and tempering, the bolting
steel ingot obtains
internal structures with uniform and fine grains. After the tempering, the
bolting steel obtains
martensite structures and a parc cf austenite sEtuctures.
100351 According to the present application, a method for preparing the
high strength
bolting steel is further provided. During the process of preparing the bolting
steel, in the
present application, firstly the bolting steel ingot is prepared, and then the
bolting steel ingot
is forged, such that grains in the bolting steel ingot are broken sufficiently
to obtain structures
with fine and uniform grains; the forged bolting steel ingot is annealed,
which eliminates
stress generated in the forging process; and finally the annealed bolting
steel ingot is
quenched and tempered, thereby obtaining martensite structures and a part of
austenite
structures having fine and uniform grains, which improves the strength and
plasticity of the
material efficiently.
.9.
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[0036] According to the elements of the bolting steel, element contents
and the
preparing method, the bolting material in the present application has high
tensile strength and
plasticity, thereby providing strong supporting, fixing and connecting for a
power arrester
device, efficiently resisting stress concentration and deviation behavior of
the arrester device
in a strong wind, and protecting a safe operation of the device. For the
material components of
the bolting steel provided by the present application, little precious metal
is contained, the
mechanical property is good, and cost-effectiveness is high. In addition, the
preparing process
for the material is simple and is convenient to apply, which may be promoted
in a large scale.
According to the present application, the strength and stiffness of the
material are improved,
thereby changing a natural frequency of the arrester device at a certain
degree, avoiding
resonance of structures due to the motivation of a strong wind, reducing
vibration amplitudes
of structures of the device, and guaranteeing a normal operation of the power
arrester device.
[0037] Hereinafter the high strength bolting steel and the preparing
method for the high
strength bolting steel are described in detail in conjunction with
embodiments, and the scope
.. of the present application is not limited by the following embodiments.
[00381 First embodiment
[0039] In the embodiment, the bolting steel contains: Ce 0.12%, C 0.37%,
Cr 1.2%, Si
0.25%, Mo 0.5%, V 0.3%, Nb 0.0048%, with remainder being Fe.
[0040 The preparing method for the bolting steel includes: step 1),
preparing a raw
material based on the above weight percentages; step 2), smelting the raw
material for 40mins
at 1560 C by a vacuum indiction tia-nace, presrving heat for 25m1ns, sampling
and casting,
and preparing an alloy steel; step 3), re-smelting the prepared alloy steel,
adding Ce and
casting into a steel ingot; step 4), perfo:ming hot-rolling on the steel ingot
obtained in step 3)
at 1150 C to obtain a hot-rolled bar, forging the hot-rolled bar at 900 C,
cooling the forged
steel ingot slowly and then annealing, wherein the annealing temperature is
650 C and the
duration of heat preservation is 2 hours; and step 5), quenching the material
obtained in step 4)
for lb at 320 'C, tempering the material at 500 'C for 60mins at 500 C, air-
cooling the
material to a room temperature to obtain a bolting steel. Performances of the
bolting steel
prepared according to the embodiment are tested, and the test result is shown
in table 1.
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Table i
data table of performances of the bolting steel prepared according to the
first embodiment
Performance index Tensile strength (Mpa) Elongation ( /0)
Performance value 1210 13.5
[0041] Second embodiment
100421 In the embodiment, the bolting steel contains: La 0.06%, Ce 0.08%, C
0.42%,
Cr 1.6%, Si 0.32%, Mo 0.72%, V 0.28%, Nb 0.0045%, with remainder being Fe.
[0043] The preparing method for the bolting steel includes: step 1),
preparing a raw
material based on the above weight percentages; step 2), smelting the material
for 40mins at
1540 C by a vacuum induction furnace, preserving heat for 20mins, sampling
and casting,
and preparing an alloy steel; step 3), re-smelting the prepared alloy steel,
adding Y and casting
into a steel ingot; step 4), performing hot-rolling on the steel ingot
obtained in step 3) at 1150
C to obtain a hot-rolled bar, forging the hot-rolled bar at 1030 C, cooling
the forged steel
ingot slowly to a room temperature and then annealing, where the annealing
temperature is
680 C and the duration of heat preservation is 2.5 hours; and step 5),
quenching the material
obtained in step 4) at 830 `C., tempering the material for 70mins at 520 C,
air-cooling the
material to a room temperature to obtain a bolting steel, where the duration
of heat
preservation for the quenching is 70mins. Performances of the bolting steel
prepared
according to the embodiment are tested, and the test result is shown in table
2.
Table 2
data table of performances of the bolting steel prepared according to the
second embodiment
Performance index Tensile strength (Nina) Elongation (%)
Performance value 1260 12.7
L_ _______________
[0044] Third embodiment
100451 In the embodiment, the bolting steel contains: La 0.05%, C 0.35%,
Cr 1.8%, Si
0.17%, Mo 0.40%, V 0.20%, Nb 0.005%, with remainder being Fe.
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[0046] The preparing method for the bolting steel includes: step 1),
preparing a raw
material based on the above weight percentages; step 2), smelting the material
for 45mins at
1550 C by a vacuum induction furnace, preserving heat for 25mins, sampling
and casting,
and preparing an alloy steel; step 3), re-smelting the prepared alloy steel,
adding Y and casting
into a steel ingot; step 4), performing hot-rolling on the obtained steel
ingot at 1150 C to
obtain a hot-rolled bar, forging the hot-rolled bar at 1000 Cr cooling the
forged steel ingot
slowly to a room temperature and then annealing, wherein the annealing
temperature is 700
C ani the duration of heat preservation is 3 hours; and step 5), quenching the
material
obtained in step 4) at 800 'C, tempering the material for 80mins at 550 C,
air-cooling the
material to a room temperature to obtain a bolting steel. Performances of the
bolting steel
prepared according to the embodiment are tested, and the test result is shown
in table 3.
Table 3
data table of performances of the bolting steel prepared according to the
third embodiment
Performance index Tensile strength (Mpa) Elongation (%)
Performance value 1300 13.0
[0047] Fourth embodiment
[00481 In the embodiment, the bolting steel contains: La 0.25%, Ce
0.25%, C 0.45%,
Cr 1.4%, Si 0.20%, Mo 0.65%, V 0.4%, Nb 0.0012%, with remainder being Fe.
[0049] The preparing method for the bolting steel includes: step 1),
preparing a raw
material based on the above weight percentage; step 2), smelting the material
for 40mins at
1540 C by a vacuum induction furnace, preserving heat for 20mins, sampling
and casting,
and preparing an alloy steel; step 3), re-smelting the prepared alloy steel,
adding Y and casting
into a steel ingot; step 4), performing hot-rolling on the obtained steel
ingot at 1150 C to
obtain a hot-rolled bar, forging the hot-rolled bar at 1030 C, cooling the
forged steel ingot
slowly to a room temperature and then annealing, wherein a temperature of
annealing is 680
C and the duration of heat preservation is 2.5 hours; and step 5), quenching
the material
obtained in step 4) at 830 C. tempering the material for 70mins at 520 C,
air-cooling the
material to a room temperature to obtain a bolting steel. Performances of the
bolting steel
prepared according to the embodiment are tested, and a test result is shown in
table 4.
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õ .õ---
Table 4
data table of performances of the bolting steel prepared according to the
fourth embodiment
Performance index Tensile strength (Mpa) Elongation (%)
Performance value 1280 13.2
100501 Fifth embodiment
[00511 A process of preparing a bolting steel in the embodiment is the same
as the
process in the first embodiment. However, in the embodiment, the bolting steel
contains: La
0.15%, Ce 0.23%. C 0.39%. Cr 1.5%. Si 0.28%, Mo 0.47%, V 0.38%, Nb 0.0014%,
with
remainder being Fe. Performances of the bolting steel prepared according to
the embodiment
are tested, and the test result is shown in table 5.
Table 5
data table of performances of the bolting steel prepared according to the
fifth embodiment
Performance index Tensile strength (Mpa) Elongation (%)
Performance value 1310 13.5
100521 Sixth embodiment
100531 A process of preparing a bolting steel in the embodiment is the
same as that in
the first embodiment. However, in the embodiment, the bolting steel contains:
Ce 0.28%, C
0.43%, Cr 1.7%, Si 0.27%, Nlo 0.77%, V 0.33%, Nb 0.0041%, with remainder being
Fe.
Performances of the bolting steel prepared according to the embodiment are
tested, and a test
result is shows as table 6.
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CA 2941276 2018-01-25
CA 02941276 2016-08-31
English translation of PCT/CN2014/081896
0P1614-09-0442
Table 6
data table of performances of the bolting steel prepared according to sixth
the embodiment
Performance index Tensile strength (Mpa) Elongation (%)
Performance value 1290 13.2
[0054] It is apparent for those skilled in the art that the present
application is not limited to
details of the exemplary embodiments, and the present application can be
implemented in
other manners without departing from the spirit or basic features of the
present application.
Thus, from any point, the embodiments should be regarded as exemplary and are
not intended
to limit. The scope of the present application is defined by the attached
claims rather than the
above description. Thus, all modifications within the concept and scope of the
claims and
equivalent thereof will fall into the scope of the present application.
[0055] In addition, it should be understood that the specification is
described according to
the embodiments, but each embodiment does not include only one independent
technical
solution. The specification is described in this way for clearance, and those
skilled in the art
should take the specification as a whole. Technical solutions in various
embodiments may be
combined appropriately to form other embodiments which can be understood by
those skilled
in the art.
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