CA2034874A1 - Wear-resistant steel for intermediate and room temperature service - Google Patents
Wear-resistant steel for intermediate and room temperature serviceInfo
- Publication number
- CA2034874A1 CA2034874A1 CA 2034874 CA2034874A CA2034874A1 CA 2034874 A1 CA2034874 A1 CA 2034874A1 CA 2034874 CA2034874 CA 2034874 CA 2034874 A CA2034874 A CA 2034874A CA 2034874 A1 CA2034874 A1 CA 2034874A1
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- Canada
- Prior art keywords
- temperature
- wear
- room
- brinell hardness
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
WEAR-RESISTANT STEEL FOR INTERMEDIATE
AND ROOM TEMPERATURE SERVICE
ABSTRACT OF THE DISCLOSURE
A wear-resistant steel for the intermediate and room temperature service consisting essentially of:
carbon : from 0.08 to 0.40 wt.%, silicon : from 0.8 to 2.5 wt.%, manganese : from 0.1 to 2.0 wt.%, and the balance being iron and incidental impurities.
The above-mentioned wear-resistant steel has a Brinell hardness at a room-temperature of at least 250, a Brinell hardness at a temperature of 300°C of at least 90% of its room-temperature Brinell hardness and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness.
AND ROOM TEMPERATURE SERVICE
ABSTRACT OF THE DISCLOSURE
A wear-resistant steel for the intermediate and room temperature service consisting essentially of:
carbon : from 0.08 to 0.40 wt.%, silicon : from 0.8 to 2.5 wt.%, manganese : from 0.1 to 2.0 wt.%, and the balance being iron and incidental impurities.
The above-mentioned wear-resistant steel has a Brinell hardness at a room-temperature of at least 250, a Brinell hardness at a temperature of 300°C of at least 90% of its room-temperature Brinell hardness and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness.
Description
~3~7~
REF~RENCE TO PATENTS, APPLICATIONS AND PUBI,ICATIONS
PERTINENT TO THE INVENTION
. . _ . .
As far as we know, there are available the following prior art documents pertinent to the present invention:
(1) Japanese Patent Provisional Publication No. 62-142,726 dated June 26, 1937;
REF~RENCE TO PATENTS, APPLICATIONS AND PUBI,ICATIONS
PERTINENT TO THE INVENTION
. . _ . .
As far as we know, there are available the following prior art documents pertinent to the present invention:
(1) Japanese Patent Provisional Publication No. 62-142,726 dated June 26, 1937;
(2) Japanese Patent Provisional Publication No. 63-169,359 dated July 13, 1988; and 10(3) Japanese Patent Provisional Publication No. 1-142,023 dated June 2, 1989.
The contents of the p.r1or art disclosed in the above-mentioned prior art documents wi.ll be discussed hereafter under the heading of the "BACKGROUND OF THE
INVENTION."
:
FIELD OF_THE INVENTION ;~
The present inventLon relates to a wear-resistant : : :
steel having a high hardness in an intermediate tempera-ture region ancl a room-temperature region.
BACKGROUND OF THE INVENTION
, , ,.
:: : :
:
` : - 2 - ~ :
::
:
, . . - : : , 2~3~
A wear-resistant steel is used as a material ~or portions exposed to serious wea~ in an indu.strial machine and a transportation machine such as a power shovel, a bulldozer, a hopper or a bucket and parts thereof. Wear resistance of steel can be improved by increasing hardness of the steel. A steel having a high hardness which contains carbon, silicon and manganese in prescribed amounts and is additionally added with elements to increase hardness, is therefore used as the wear-resistant steel mentioned above.
.
The following wear-resistant steels have so far been proposed as steels excellen~ in wear resistance and satlsfactory in weldabllity, toughness and workabillty~
(1) A wear-resistant steel sheet having an~excellent weldability, disclosed in Japanese Patent Provisional ` ;
Publicatlon No. 62-142,726 dated June~26j 1987, whlch consists essentially o~
carbon : from 0.10 to O.l9 wt.%, silicon : : from O . 05 to O. 55 wt.
manganese : from 0.90 to 1.60 wt.%, and the balance being iron an~ incidental impuri~.ies;
where, a carbon;eguivalent (C + 1/24 Si~ T
- 1/6 Mn +~l/40 Ni + :1/5 Cr ~ 1/4~ Mo * 1/14 V)~
~ - 3 :. : - . ,, , . : . :. , , - :: :: :
being within a range of from 0.35 to 0.44 wt.%
(hereinafter eierred to as ~he "prior art 1").
The above-mentioned wear-resistant steel sheet of the prior art 1 may additionally contain at least one of vanadium and niobium in an amount of up to 0.10 wt.%.
(2) A wear-resistant steel sheet having a high toughness, disclosed in Japanese Patent Provisional Publication No. 63-169,359 dated July 13, 1988, which consists essentially of: ~
carbon ~ : from 0.~10 to 0.20 wt.%, sillcon ~ - from~0.03 to 0.75 wt.%, manganese~ from C. 4 to 1.8~wt.~, phosphorus ~ ~: up to 0.015 wt.%, sulfur ~ : up to~0.002 wt.
nitrogen ~ ;up to 0~0025 wt.%~
sol. Al ~ ~: from~;0~.001 ~to 0.080 wt.%, oxygen ~ up to 0~.0020 wt.
and the balance belng~iron~and lnclden~tal l~purlties (hereinafter referred to~as the "prior art"). ~
The above-mentioned we.r-resistant steel sheet af the prior art Z may~additionally contain Rt least~one elemen~ selected;~rom the~group~consisting o~
:
. ., . : : ~ . . :
7 ~
copper : from 0.05 to 0.75 wt.%, nickel : from 0.05 to 1.50 wt.%, c~romium : from 0.05 to 1.50 wt.%, molybdenum : from 0.01 to 0.75 wt.%
and boron : from 0.0001 to 0.0025 wt.%.
The contents of the p.r1or art disclosed in the above-mentioned prior art documents wi.ll be discussed hereafter under the heading of the "BACKGROUND OF THE
INVENTION."
:
FIELD OF_THE INVENTION ;~
The present inventLon relates to a wear-resistant : : :
steel having a high hardness in an intermediate tempera-ture region ancl a room-temperature region.
BACKGROUND OF THE INVENTION
, , ,.
:: : :
:
` : - 2 - ~ :
::
:
, . . - : : , 2~3~
A wear-resistant steel is used as a material ~or portions exposed to serious wea~ in an indu.strial machine and a transportation machine such as a power shovel, a bulldozer, a hopper or a bucket and parts thereof. Wear resistance of steel can be improved by increasing hardness of the steel. A steel having a high hardness which contains carbon, silicon and manganese in prescribed amounts and is additionally added with elements to increase hardness, is therefore used as the wear-resistant steel mentioned above.
.
The following wear-resistant steels have so far been proposed as steels excellen~ in wear resistance and satlsfactory in weldabllity, toughness and workabillty~
(1) A wear-resistant steel sheet having an~excellent weldability, disclosed in Japanese Patent Provisional ` ;
Publicatlon No. 62-142,726 dated June~26j 1987, whlch consists essentially o~
carbon : from 0.10 to O.l9 wt.%, silicon : : from O . 05 to O. 55 wt.
manganese : from 0.90 to 1.60 wt.%, and the balance being iron an~ incidental impuri~.ies;
where, a carbon;eguivalent (C + 1/24 Si~ T
- 1/6 Mn +~l/40 Ni + :1/5 Cr ~ 1/4~ Mo * 1/14 V)~
~ - 3 :. : - . ,, , . : . :. , , - :: :: :
being within a range of from 0.35 to 0.44 wt.%
(hereinafter eierred to as ~he "prior art 1").
The above-mentioned wear-resistant steel sheet of the prior art 1 may additionally contain at least one of vanadium and niobium in an amount of up to 0.10 wt.%.
(2) A wear-resistant steel sheet having a high toughness, disclosed in Japanese Patent Provisional Publication No. 63-169,359 dated July 13, 1988, which consists essentially of: ~
carbon ~ : from 0.~10 to 0.20 wt.%, sillcon ~ - from~0.03 to 0.75 wt.%, manganese~ from C. 4 to 1.8~wt.~, phosphorus ~ ~: up to 0.015 wt.%, sulfur ~ : up to~0.002 wt.
nitrogen ~ ;up to 0~0025 wt.%~
sol. Al ~ ~: from~;0~.001 ~to 0.080 wt.%, oxygen ~ up to 0~.0020 wt.
and the balance belng~iron~and lnclden~tal l~purlties (hereinafter referred to~as the "prior art"). ~
The above-mentioned we.r-resistant steel sheet af the prior art Z may~additionally contain Rt least~one elemen~ selected;~rom the~group~consisting o~
:
. ., . : : ~ . . :
7 ~
copper : from 0.05 to 0.75 wt.%, nickel : from 0.05 to 1.50 wt.%, c~romium : from 0.05 to 1.50 wt.%, molybdenum : from 0.01 to 0.75 wt.%
and boron : from 0.0001 to 0.0025 wt.%.
(3) A wear-resistant steel sheet having an excellent bending workability, disclosed in Japa~ese Patent Provi-sional Publication No. 1-142,023 dated June 2, 1989, which consists essentially of:
carbon : from 0.07 to 0.17 wt.%, ~, . .
silicon from 0.05~ to 0.55 wt.%, manganese : from 0.70 to 1.80 wt.%, vanadium ~ : from 0.02 to 0.10 wt.~%, boron ~ :~from 0 0003 to 0.0050;wt.%~
aluminum :~from 0.01~ ~to O.lO~wt.%, ~ i-and the balance being iron and~lncidental impurities ;hareinafter referred~to as the~"prlor~art 3")~
~: : , : ~
The above-mentioned wear-resistant ste~.l sheet ~
~ ; , : : :
of the prior art 3 may additionally contain at least one element selected;from the~grou~ consi~stlng of:~
:
copper ~ from 0.05 to 0.30 wt.%, nichel~ : from O.OS~to 0.45 wt.%, `
- 5 ~ ~ ~
, : ~ . : : . , : ~ .
~0~87~
chromium : from 0.05 to 0.20 wt.%, and molybdenum : fro~n 0.03 to 0.20 wt.~.
According to the above-ment.ioned prior arts 1 to 3, a wear-resistant steel having a high room-tempera-ture hardness is available in all cases. However, the prior arts 1 to 3 have the following problems: ~ wear-resistant steel is used also as a material for a machine and parts thereof for treatlng slag at a temperature within an intermediate temperature region of from about 300 to about 400C in a slag yArd. A wear-resistant steel used as such a material should preferably have a Brinell hardness(HB) at a room-temperature~of at~least:
250, a Brinell hardness~at:a~temperature of~ about 300C~ -of at least 90% of its room-tempèrature Brinel~l hardness,~
and a Brinell hardness at a temperature~ of about:400C ::
of at least 70% of its:room-:temperature Brinel~l;hardness.
However, according to the wear-reslstant~steels of the prior arts l~to 3, whl1e it ls possible~to~lmprove wear resista7lce at a temperature within a room~temperature region, it: lS lmpossible to lmprove~ear~reslstance~at a temperature with:;n an intermedLal'e:temperature:~region of from about 300 to~ahout~400C.~ The wear-resis~tant~
ste~ls of the prior~arts l to ~a~re not satisfactory i~n :: : : .
terms of wear~reslstance:when used~as~a:material~for a - 6 -~
:
::
. -;, - : , :
~3~7~
machine and parts thereof employel at a temperature within an intermediate temperature region.
With a view to improving wear resistance at a temperature within an intermediate temperature region, a conceivable measure is to largely increase a room-temperature hardness of steel, kaking account of the decrease in hardness at a temperature within an interme-diate temperature region. When a room-temperature hardness of steel is increased excessively, however, ductility, toughness, workability and weldability o~ the steel are deteriorated. --Under such circumstances, there is a strong demand for the development of a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250~ ~
and has a Brinell hardness at a temperature of about 300C
of at least 90% of its room temperature Brinell hardness, and a Brinell hardness at a temperature of about 400C
of at least 70% of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely lnCreaSing its room-temperature Brinell hardness, ~ ~ -but SUC_l ~a wear-resistant ~:teel eor the intermediate and room temperature~service has not as yet been proposed.
:: : : ::
SUM~RY OF~THE INVENTION ~ ~ ~
_ 7 _ ~ -. : . : : : : , . ::~ : . :
, ~J3~ 7 An object of the present invention is therefore to provide a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, and has a Brinell hardness at a temperature of 300C of at least 90% of its room-temperature Brinell hardness and a Brinell hardness at a temperature of 400C of at least 70% of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely increasing its room-temperature Brinell hardness.
:
In accordance with one o~f the features of the present invention, there is provided a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a~room-temperature of ~
, at least 250, a Brinell hardness at~a temperature~of;
300C of at least 90% of its room-temperature Brinell hardness/and a Brinell hardness at a temperature of 430C
of at least 70~ of its room-temperature Brinell hardness, characterized hy consisting essentially of:
carbon ~: from 0.08;~to~0.40~wt~%, ;
silicon : from;0.8 to~2.S ~wt.%,~
manganese : from~0.1 to ~.O wt.
and - ~
the bal~ance being iron and inciden~al impu~ities.
The wear-reslstant~ste~l~for the intermedi~te .
~.~3~7~
and room temperature service of the present invention may additionally contain at least one element selected from the group (A) consistinc of:
(A) copper : from 0.1 to 2.0 wt.~, nickel : from 0.1 to 10.0 wt.~, i chromium : from 0~1 to 3.0 wt.~, molybdenum : from 0.1 to 3.0 wt.~, and boron : from 0.0003 to 0.0100 wt.~.
The wear-resistant steel for the 1ntermediate and : .
room temperature service of the~present invention`may additionally contain at least one element selected from the group (B) consisting of:
:
(B) niobium : from O.OOS to O.lOO`wt.~, vanadium : from 0.01 to 0.~10 wt.~, and titanium : from O~OO5 to 0~.100 wt.
Furthermore, the wear-resistant~stee1~for the~
intermediate and -room temperature service of the~present invention may addLtion~lly~contain at least~one element~
selected from the above-mentioned group~ (A)~and~at~least one~element selected from the above-mentioned group (B).
:
, ~3~7~
BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is a graph illustrating the relationship between a silicon content and a Brinell hardness (HB) in a wear-resistant steel.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
From the above-mentioned point of view, extensive studies were carried out to develop a wear-resistant steel for the intermediate and room temperature service having an excellent wear resistance in an intermediate temperature region without largely incxeasing its room-temperature hardness. As a result, findlngs were obtained that silicon contained in steel had a function of increasing, for a certain range of the content thereof, hardness of steeI ln an intermedlate temperature region without increasing a room-temperature hardness thereof.
The present invention was made on the basis of the above-mentioned findings, and the wear-resistant st~el for the intermediate and room temperature service of tne present invention consists essentially of:
~0 carbon : from 0.08 to 0~40 wt.~, silicon ~ : fxom 0. 8 to 2 . 5 wt. ~o;, manganese ~ ~: from 0.1 to 2.0 wt.~, and the balance~ being iron and~incidental impurities.
-- 1 0 -- ~
3-~87~
The wear-resistant steel for the intermediate and room temperature service of ~he presen~ invention may additionally contain at least one e'ement selected from the group (A) consisting of:
(A) copper : from 0.1 to 2.0 wt.~, nickel : from 0.1 to 10.0 wt.%, chromium : from 0.1 to 3.0 wt.%, molybdenum : from 0.1 to 3.0 wt.%, and boron : from 0.000~3 to O~.OlOO wt.~.
The wear-resistant steel for the~intermediate~and room temperature service of the present~invention may additionally contain at least one element~selected from the group (B) consisting of~
niobium : from 0.005 to~0.;100 wt.%,~
vanadium : from O.0~1 to~O.lO~ wt.%,;
and ;~
titanium : from O.OO5~to O~.~lOO~wt.
Purthermore, the wear-res1stant steel~ for the~
intermediate and room tem~erature~service~o~the~present iDVentlon may additionally contain~at~least one~elemQnt selected from the above-mentloned group~(Aj and at~least onè element selected from the~above-men~tioned group tB).
.~ .. ,: ~ ,, , . . . : , ~3~7~
The chemical composition of the wear-resistant steel for ~he intermediate and room temperature service of the p~esent invention is limited within a range as described above for the following reasons.
(1) Carbon:
Carbon is an element which exerts an important effect on hardness of steel. ~owever, with a carbon content of under 0~08 wt.%, a Brinell hardness (HB) a~
a room-temperature of at least 250 is not availab1e.
With a carbon content of over 0.40 wt.%, on the other ~ ~
hand, a room-temperature Brinell hardness becomes excessively high to result in deteriorati~on of ductility, toughness, workability~and weldability of s~teel.~The carbon content should therefore be limited wi~hin a~
range of from 0.08 to 0.40 wt.
~2) Silicon~
Silicon has a function of increasing`~hardness of steel in an intermedlate~temperature re~lon without~
increaslng its room-temperature hardne3s.~ owever,~with~
a silicon content of under 0.8 wt.~,~a~desired~effect~as~
mentione~;abo-ve 13 ~not av~1lable.
The relationship between a silicon content and a Brinall hardness (HB) in a Wear-reSlStant steel was nvestigated. More particularly, for test pieces~o ~ - 12 -~
: ~
-, :-; , ~ ~ , : .
: ~ , . .. . .
2~87~
hardened wear-resistant steel haviny a thickness of 20 mm, which containec 0.3 wt.~ carbon, 0.7 wt.% manganese, 0.9 wt.~ chromium and silicon in a certain amount, a Brinell hardness (HB) was measured for each test piece at a S room-temperature, 300C, 400C and 500C with the silicon content varying within a range of from about 0.4 to about 2.0 wt.~. The results are shown in Fig. 1.
In Fig. 1, the mark "o" represents a Brinell hardness at a room-temperature of the test piece; the mark "e" represents a Brinell hardness at a temperature of 300C of the test piece; the mark ~"~" represents a Brinell hardness at a temperature of~400C of the test piece; and the mark "~" represents a Bri~nell hardness at a temperature of 500C of the test piece. As shown in Fig. 1, the test pieces showed a Brinell hardness~at~a room-temperature of about 500 almost constantly irrespec-, tive of the increase in the silicon content. The test ~ .
pieces showed a Brinell~hardness at a~temperature of~
300C of at least 450, i.e., about 90% of lts room-~0 tr~mperature Brinell hardness by increasing the silic~n content to at least 0.8 wt.~. The test~pLeoes~showed a Brir.ell hardness at a temperature of 400C of at least 350, i.e.j about 70% of~lts room-temperature~Brlnell~
har~ness by increasing the siliCQn~content ~o at least :: :
25 0.8 wt.~. The test pieces showed a;Brinell~hardness at ~ `
~ ~ :
~:
~ - 13 -:
~;7~ 7 a temperature of 500~C also increased, though on a rela-tively low level~ by increasing the silicon content to at least 0.8 wt.~.
With a silicon content of over 2.5 wt.%, on the other hand, ~-ferrite is produced in the steel structure, and this may cause degradation of a room-temperature hardness o~ steel, and the manufacturing cost of steel becomes higher. The silicon content should therefore be limited within a range of from 0.8 to 2.5 wto~.
~3) Manganese: ~ ~
Manganese has a function of~improvlng hardenability of steel. However, with a manganese content of under~0.~
wt.%, a desired effect as mentioned above ;l~s not~available.
With a manganese content of over 2.0 wt.~ on the~other `
handr weldability of steel is degraded,; and the~manufactur~
ing Fost of steel becomes hlgher.~ The manganese content should therefore be limited within a range~of;from 0.1 to 2.0 wt.%.
carbon : from 0.07 to 0.17 wt.%, ~, . .
silicon from 0.05~ to 0.55 wt.%, manganese : from 0.70 to 1.80 wt.%, vanadium ~ : from 0.02 to 0.10 wt.~%, boron ~ :~from 0 0003 to 0.0050;wt.%~
aluminum :~from 0.01~ ~to O.lO~wt.%, ~ i-and the balance being iron and~lncidental impurities ;hareinafter referred~to as the~"prlor~art 3")~
~: : , : ~
The above-mentioned wear-resistant ste~.l sheet ~
~ ; , : : :
of the prior art 3 may additionally contain at least one element selected;from the~grou~ consi~stlng of:~
:
copper ~ from 0.05 to 0.30 wt.%, nichel~ : from O.OS~to 0.45 wt.%, `
- 5 ~ ~ ~
, : ~ . : : . , : ~ .
~0~87~
chromium : from 0.05 to 0.20 wt.%, and molybdenum : fro~n 0.03 to 0.20 wt.~.
According to the above-ment.ioned prior arts 1 to 3, a wear-resistant steel having a high room-tempera-ture hardness is available in all cases. However, the prior arts 1 to 3 have the following problems: ~ wear-resistant steel is used also as a material for a machine and parts thereof for treatlng slag at a temperature within an intermediate temperature region of from about 300 to about 400C in a slag yArd. A wear-resistant steel used as such a material should preferably have a Brinell hardness(HB) at a room-temperature~of at~least:
250, a Brinell hardness~at:a~temperature of~ about 300C~ -of at least 90% of its room-tempèrature Brinel~l hardness,~
and a Brinell hardness at a temperature~ of about:400C ::
of at least 70% of its:room-:temperature Brinel~l;hardness.
However, according to the wear-reslstant~steels of the prior arts l~to 3, whl1e it ls possible~to~lmprove wear resista7lce at a temperature within a room~temperature region, it: lS lmpossible to lmprove~ear~reslstance~at a temperature with:;n an intermedLal'e:temperature:~region of from about 300 to~ahout~400C.~ The wear-resis~tant~
ste~ls of the prior~arts l to ~a~re not satisfactory i~n :: : : .
terms of wear~reslstance:when used~as~a:material~for a - 6 -~
:
::
. -;, - : , :
~3~7~
machine and parts thereof employel at a temperature within an intermediate temperature region.
With a view to improving wear resistance at a temperature within an intermediate temperature region, a conceivable measure is to largely increase a room-temperature hardness of steel, kaking account of the decrease in hardness at a temperature within an interme-diate temperature region. When a room-temperature hardness of steel is increased excessively, however, ductility, toughness, workability and weldability o~ the steel are deteriorated. --Under such circumstances, there is a strong demand for the development of a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250~ ~
and has a Brinell hardness at a temperature of about 300C
of at least 90% of its room temperature Brinell hardness, and a Brinell hardness at a temperature of about 400C
of at least 70% of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely lnCreaSing its room-temperature Brinell hardness, ~ ~ -but SUC_l ~a wear-resistant ~:teel eor the intermediate and room temperature~service has not as yet been proposed.
:: : : ::
SUM~RY OF~THE INVENTION ~ ~ ~
_ 7 _ ~ -. : . : : : : , . ::~ : . :
, ~J3~ 7 An object of the present invention is therefore to provide a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, and has a Brinell hardness at a temperature of 300C of at least 90% of its room-temperature Brinell hardness and a Brinell hardness at a temperature of 400C of at least 70% of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely increasing its room-temperature Brinell hardness.
:
In accordance with one o~f the features of the present invention, there is provided a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a~room-temperature of ~
, at least 250, a Brinell hardness at~a temperature~of;
300C of at least 90% of its room-temperature Brinell hardness/and a Brinell hardness at a temperature of 430C
of at least 70~ of its room-temperature Brinell hardness, characterized hy consisting essentially of:
carbon ~: from 0.08;~to~0.40~wt~%, ;
silicon : from;0.8 to~2.S ~wt.%,~
manganese : from~0.1 to ~.O wt.
and - ~
the bal~ance being iron and inciden~al impu~ities.
The wear-reslstant~ste~l~for the intermedi~te .
~.~3~7~
and room temperature service of the present invention may additionally contain at least one element selected from the group (A) consistinc of:
(A) copper : from 0.1 to 2.0 wt.~, nickel : from 0.1 to 10.0 wt.~, i chromium : from 0~1 to 3.0 wt.~, molybdenum : from 0.1 to 3.0 wt.~, and boron : from 0.0003 to 0.0100 wt.~.
The wear-resistant steel for the 1ntermediate and : .
room temperature service of the~present invention`may additionally contain at least one element selected from the group (B) consisting of:
:
(B) niobium : from O.OOS to O.lOO`wt.~, vanadium : from 0.01 to 0.~10 wt.~, and titanium : from O~OO5 to 0~.100 wt.
Furthermore, the wear-resistant~stee1~for the~
intermediate and -room temperature service of the~present invention may addLtion~lly~contain at least~one element~
selected from the above-mentioned group~ (A)~and~at~least one~element selected from the above-mentioned group (B).
:
, ~3~7~
BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is a graph illustrating the relationship between a silicon content and a Brinell hardness (HB) in a wear-resistant steel.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
From the above-mentioned point of view, extensive studies were carried out to develop a wear-resistant steel for the intermediate and room temperature service having an excellent wear resistance in an intermediate temperature region without largely incxeasing its room-temperature hardness. As a result, findlngs were obtained that silicon contained in steel had a function of increasing, for a certain range of the content thereof, hardness of steeI ln an intermedlate temperature region without increasing a room-temperature hardness thereof.
The present invention was made on the basis of the above-mentioned findings, and the wear-resistant st~el for the intermediate and room temperature service of tne present invention consists essentially of:
~0 carbon : from 0.08 to 0~40 wt.~, silicon ~ : fxom 0. 8 to 2 . 5 wt. ~o;, manganese ~ ~: from 0.1 to 2.0 wt.~, and the balance~ being iron and~incidental impurities.
-- 1 0 -- ~
3-~87~
The wear-resistant steel for the intermediate and room temperature service of ~he presen~ invention may additionally contain at least one e'ement selected from the group (A) consisting of:
(A) copper : from 0.1 to 2.0 wt.~, nickel : from 0.1 to 10.0 wt.%, chromium : from 0.1 to 3.0 wt.%, molybdenum : from 0.1 to 3.0 wt.%, and boron : from 0.000~3 to O~.OlOO wt.~.
The wear-resistant steel for the~intermediate~and room temperature service of the present~invention may additionally contain at least one element~selected from the group (B) consisting of~
niobium : from 0.005 to~0.;100 wt.%,~
vanadium : from O.0~1 to~O.lO~ wt.%,;
and ;~
titanium : from O.OO5~to O~.~lOO~wt.
Purthermore, the wear-res1stant steel~ for the~
intermediate and room tem~erature~service~o~the~present iDVentlon may additionally contain~at~least one~elemQnt selected from the above-mentloned group~(Aj and at~least onè element selected from the~above-men~tioned group tB).
.~ .. ,: ~ ,, , . . . : , ~3~7~
The chemical composition of the wear-resistant steel for ~he intermediate and room temperature service of the p~esent invention is limited within a range as described above for the following reasons.
(1) Carbon:
Carbon is an element which exerts an important effect on hardness of steel. ~owever, with a carbon content of under 0~08 wt.%, a Brinell hardness (HB) a~
a room-temperature of at least 250 is not availab1e.
With a carbon content of over 0.40 wt.%, on the other ~ ~
hand, a room-temperature Brinell hardness becomes excessively high to result in deteriorati~on of ductility, toughness, workability~and weldability of s~teel.~The carbon content should therefore be limited wi~hin a~
range of from 0.08 to 0.40 wt.
~2) Silicon~
Silicon has a function of increasing`~hardness of steel in an intermedlate~temperature re~lon without~
increaslng its room-temperature hardne3s.~ owever,~with~
a silicon content of under 0.8 wt.~,~a~desired~effect~as~
mentione~;abo-ve 13 ~not av~1lable.
The relationship between a silicon content and a Brinall hardness (HB) in a Wear-reSlStant steel was nvestigated. More particularly, for test pieces~o ~ - 12 -~
: ~
-, :-; , ~ ~ , : .
: ~ , . .. . .
2~87~
hardened wear-resistant steel haviny a thickness of 20 mm, which containec 0.3 wt.~ carbon, 0.7 wt.% manganese, 0.9 wt.~ chromium and silicon in a certain amount, a Brinell hardness (HB) was measured for each test piece at a S room-temperature, 300C, 400C and 500C with the silicon content varying within a range of from about 0.4 to about 2.0 wt.~. The results are shown in Fig. 1.
In Fig. 1, the mark "o" represents a Brinell hardness at a room-temperature of the test piece; the mark "e" represents a Brinell hardness at a temperature of 300C of the test piece; the mark ~"~" represents a Brinell hardness at a temperature of~400C of the test piece; and the mark "~" represents a Bri~nell hardness at a temperature of 500C of the test piece. As shown in Fig. 1, the test pieces showed a Brinell hardness~at~a room-temperature of about 500 almost constantly irrespec-, tive of the increase in the silicon content. The test ~ .
pieces showed a Brinell~hardness at a~temperature of~
300C of at least 450, i.e., about 90% of lts room-~0 tr~mperature Brinell hardness by increasing the silic~n content to at least 0.8 wt.~. The test~pLeoes~showed a Brir.ell hardness at a temperature of 400C of at least 350, i.e.j about 70% of~lts room-temperature~Brlnell~
har~ness by increasing the siliCQn~content ~o at least :: :
25 0.8 wt.~. The test pieces showed a;Brinell~hardness at ~ `
~ ~ :
~:
~ - 13 -:
~;7~ 7 a temperature of 500~C also increased, though on a rela-tively low level~ by increasing the silicon content to at least 0.8 wt.~.
With a silicon content of over 2.5 wt.%, on the other hand, ~-ferrite is produced in the steel structure, and this may cause degradation of a room-temperature hardness o~ steel, and the manufacturing cost of steel becomes higher. The silicon content should therefore be limited within a range of from 0.8 to 2.5 wto~.
~3) Manganese: ~ ~
Manganese has a function of~improvlng hardenability of steel. However, with a manganese content of under~0.~
wt.%, a desired effect as mentioned above ;l~s not~available.
With a manganese content of over 2.0 wt.~ on the~other `
handr weldability of steel is degraded,; and the~manufactur~
ing Fost of steel becomes hlgher.~ The manganese content should therefore be limited within a range~of;from 0.1 to 2.0 wt.%.
(4) Copper~
Copper has a fun~tlon~of lmproving~hardenabillt~
of steel. In the wear-resistant steeI of the present invention, therefore, copper is additionally ad~ed as required.; However, wlth a copper con~ent of under~0.1 wt.%, a desired efLec~; as ~wentioned~above;is~not ava~lable.
2)~3~7~
With a copper content of o~er 2.0 wt.~, on the other hand, hot workability of steel is degraded. The copper content should therefore be limited within a range of from O.l to 2.0 wt.~.
Copper has a fun~tlon~of lmproving~hardenabillt~
of steel. In the wear-resistant steeI of the present invention, therefore, copper is additionally ad~ed as required.; However, wlth a copper con~ent of under~0.1 wt.%, a desired efLec~; as ~wentioned~above;is~not ava~lable.
2)~3~7~
With a copper content of o~er 2.0 wt.~, on the other hand, hot workability of steel is degraded. The copper content should therefore be limited within a range of from O.l to 2.0 wt.~.
(5) Nickel:
Nickel has a function of improving hardenability and low-temperature ~oughness of steel. In the wear-resistant steel of the present invention, therefore, nickel lS additionally added as required. However, ~ith a nickel content of under O.l wt.%, a~desired effect as mentioned above is not avaL1ab1e. With~a nickel content of over lO.0 wt.%, on the other handi the~manufacturing cost of steel becomes higher. The nickel content~should~
:~ .
therefore be limited within a-range of from O.l to lO.0 wt.%.
.
Nickel has a function of improving hardenability and low-temperature ~oughness of steel. In the wear-resistant steel of the present invention, therefore, nickel lS additionally added as required. However, ~ith a nickel content of under O.l wt.%, a~desired effect as mentioned above is not avaL1ab1e. With~a nickel content of over lO.0 wt.%, on the other handi the~manufacturing cost of steel becomes higher. The nickel content~should~
:~ .
therefore be limited within a-range of from O.l to lO.0 wt.%.
.
(6) Chromium:
::
Chro~ium has a function of 1mprov1ng hardenab1lity ~;
of steel. In the wear-resistant steel of the present invention, therefore,~chromium lS ~additionally added as~
required. However~ with a chromium content of under~0~
;tt.~, a desired ~3ffect ~as~ ment1~oned~above~;is~not~av-9-1ab1e.
With a chrom1um content~of over ~.O~wt.~, on the~other hand, weldàbility of steel~is degraded~, and the manufactur- `
ing cost~of ste~l becomes higher.~The chromium content ;
showld therefore be limited withi~ a range of from 0.1 to ~ - 15 - ~
.
8 7 ~
3.n wt.%.
::
Chro~ium has a function of 1mprov1ng hardenab1lity ~;
of steel. In the wear-resistant steel of the present invention, therefore,~chromium lS ~additionally added as~
required. However~ with a chromium content of under~0~
;tt.~, a desired ~3ffect ~as~ ment1~oned~above~;is~not~av-9-1ab1e.
With a chrom1um content~of over ~.O~wt.~, on the~other hand, weldàbility of steel~is degraded~, and the manufactur- `
ing cost~of ste~l becomes higher.~The chromium content ;
showld therefore be limited withi~ a range of from 0.1 to ~ - 15 - ~
.
8 7 ~
3.n wt.%.
(7) Moly-bdenum:
Similarly to chromium, molybdenum has a function of improving hardenability of steel. In the wear-resistant steel of the present invention, therefore, molybdenum is additionally added as required. However, with a molybdenum content of under O.l wt.~, a desired effect as mentioned above is no~ available. With a molybdenum content of over 3.0 wt.%, on the other hand, weldability of steel is degraded and the manufacturing cost o~ steel becomes higher. The molybdenum content should therefore be limited within a range of from O.l to 3.0 wt.%.
Similarly to chromium, molybdenum has a function of improving hardenability of steel. In the wear-resistant steel of the present invention, therefore, molybdenum is additionally added as required. However, with a molybdenum content of under O.l wt.~, a desired effect as mentioned above is no~ available. With a molybdenum content of over 3.0 wt.%, on the other hand, weldability of steel is degraded and the manufacturing cost o~ steel becomes higher. The molybdenum content should therefore be limited within a range of from O.l to 3.0 wt.%.
(8) Boron:
Boron has a Eunction of improving~hardenability o~
steel with a slight content. In;the~wear-resl$tant~steel of the present invention, thereore,~boron;is additionally added as required. However, with a boron content of under 0.0003 wt.~, a desired effect as mentioned above is not available. With a boron;content~of over O.O100 ~O wt.~, on the other hand, weldability and hardenability of~
steel are degraded. ~The boron~;-ontent should~therefore be limi.ted within a range~of ~rom 0.00~03~to 0.OlOU wt.%;.
~9) Niobium~
~iobium has a iunc-ion Gf impro-i~n~ bardnes6 of ~ ;
16~
,, ,: . : ~: . ~:
:, . .
7 ~
steel through precipitation hardening. In the wear-resistant steel of the present invention, therefore, niobium is additionally a~ded as rPquired. ~owever, with a niobium content of under 0.005 wt.%, a desired effect as mentioned above is not available. With a niobium content of over 0.100 wt.~, on the other hand, weldability of steel is degraded. The niobium content should therefore be limited within a range of from 0.005 to 0.100 wt.%.
(10) Vanadium Similarly to niobium, vanadium has a function of improving hardness of steel through precipitation hardening.
In the wear-resistant steel of the present invention, therefore, vanadium is additionally added as required.
However, with a vanadium coDtent of under 0.01 wt.%, a desired effect as mentioned above is not available.
With a vanadium content of over 0.10 wt.~, on the other hand, weldability of steel is degraded. The vanadium content should therefore be limited within a range of ~xom 0.01 to O.lQ wt.~.
: ~
(11) Titanium~ ~
Similai-ly to n~obium, itanium has a function of improving ha~dness Or steel through precipi~atlon hardening. In the wear-resistant steel of the present :
invention, therefore, titaniw,l is additionally added as required. Howeve~^, with a titanium content of under ~ - 17 -7 ~
0.005 wt.~, a desired effect as mentioned above is not available. With a titanium content of over 0~100 wt.%, weldability of steel i5 degraded. The titanium content should therefore be lim.ited within a range of from 0.005 to 0.100 wt.%.
In the present invention, for example, a slab of a wear-resistant steel having the above-mentioned chemical composition may be hot-rolled to prepare a steel sheet, and the thus prepared steel sheet may be subjected to heat treatments including a hardening treatment,~ a tempering treatment, an ageing treatment and a s~ress relieving treatment. Hardness~ and toughness of the steel sheet can further be improved by the~application of these heat treatments thereto. ;~
Now, the wear-reslstant steel of the present invention is described more in~detail by means of examples while comparing with a wear-resistant steel for comparison outside the scope of the present l~nVentlon.
EXA~SPLES
Ingots of the wear-resistant steel of the present invention havlng the chemical compositions withln the ~
scop~ of the present ir.ventlon as shown in Table l, an~d ingots of a wear-resistant steel for comparison having the chemical composltions outslde the s~ope of ~he :- 18 ~
:
: ~: .
~3~87~
present invention as shown also in Table 1, were melted in a melting .l`urnace, and then cast into slabs. The resultant slabs were then hot-rolled to prepare samples of the wear-resistant steel of the present invention (herein-after referred to as the "samples of the invention") Nos. 1 to 13 having a thickness of 15 mm, and samples of the wear-resistant steel for comparison outside the scope of the present invention (hereinafter referred to as the "samples for comparison") Nos. 1 to 4 also having a thickness of 15 mm.
The samples of the invention Nos. 1 to 4 and 6 to 13, and the samples for comparison Nos~ 1 to 3 were subjected to any one of the following heat treatments as shown in the column of "heat treatment" in Table l.~ The sample of the invention No. 5;and~the sample for comparison No. 4 were maintained in~the~as-rolled state without being subjected to any heat treatment. ~ ~
(1) A sample is hardened by heating the sample to a temperature of 900C and then water-quenching the heated sample from the above-mentioned temperature (hereinafter, this heat treatm~nt being referred to as the "RQ")i (j) A sample is subjected:to the~above-mentio4ed RQ, and then tempered at a temperature as shown in the parentheses in the column of "heat t.reatment" in Table 1 , (hereinafter, thls heat~treatment being referred to as 19 -; ~
-- - . : . , ~ - ' ~ , :,: , 8~
the "RQT");
t3) A sample is directly hardened by immediately water-quenching the samp~e from the hot-rolling finishing temperature (hereinafter, this heat treatment being referred to as the "nQ"); and (4) A sample is subjected to the above-mentioned DQ, and then tempered at a temperature as shown in the paren-theses in the column of "heat treatment" in Table l (hereinafter, this heat treatment being referred to as the "DQT").
Then, for each of the samples of the invention Nos. l to 13 and the samples for comparison Nos, l to 4, a Brinell hardness (HB) at a room-temperature, a Brinell hardness at a temperature of 300C and a Br1ne11 hardness at a temperature of 400C were investigated. ~ThP results are shown in ~able 2. In the column of "Brinell hardness (HB)" in Table 2, the values of Brinell hardness shown in the subcolumns oE "at 300C" and "at 400-C" were~
obtain~d by converting the values measured in the tensile 2Q test, although the values of Brinell hardness showr. In the subcolumn of "at room-temperature" were obtained by means of the Brinell test. Each va1ue of percentages shown in~the parentheses in the subcolumns of "at 300C"
~ and "at 400~C"~presents a ratio of each value of Brinell hardnesses ~at temperatures of 300C and 400C to a value of its Brinell hardness at a room-temperature.
' .
.J ~ ~ ~ ~ a _ u o ~ a o ~1~ a a ~ _ ~ ~ _ _ _ _ ~ E~ ._ C~ _ _ _ _ _ _ Ql Ql a) Ql ~1) Q) C) Ql 5) a) Ql a) (U IU a~ a) ~1) r r-l r I r-l r1 r1 r-l r1 r~ r1 r-J r-l r-l r-l r l r~ r-l rl r _ _ _ J __ _ . O O O O O _ __ _ r _ ~ l l l l l l ~ O l l O O l l l c l _ _ _ _ _ _ _ _ N U~ _ O O ~ _ _ O _ ,~0 ~ ~ ~
r t.l _ _ _ _ O O O _ _ _ O O _ _ _ O _ ~LI~ t~t~ i O~ 1~1 O r-l ~ ~ O r-l O O O ~1 O rl ~ rl ~ 1~ CO CO I~ I_ ~_ 1~ ~ G ~r 1~ U~ It~ 1~ 1~ 1~ t--_ O O O O O O O ~ r-l O r-l _ O O O O
N ~ ~ ~1 ~ C~ N N C O ~) ~1 CO ~D ~ r l N r 1 r O r: N r~ r~ r-l r-l r-l O~ O O r; O N O O r1 _ ~ _ --- - -1- - -- -- - ~
~ ,.o~ o ~r ~ ~ 1 O O O u~
r1 N l r ¦ N r-l r1 ¦ N ¦ (`'1 ~¦
L~ uo~uaJ~u~ a~ 30 aldwes uosl~edwo -- 21 -- .
.
8 ~ ~
Table 2 _ ~
Brinell hardness (HB) ~o . . . ~ __ . __ ._ _ _ At room- At 300CAt 400C
m~ _. _ . __ _ 1518 477 (92%)383 (74%) _ ._ _.
. 2481 ~ 441 (92%)361 (75%) 3510 477 ~94%)448 (88%) , o 449g 461 (92%)388 (78~) .~ _ 5304 280 (92%)221 (73%3 ~ _ :
.~ 6522 495 -(g5%)~395 ~76%) _ . . ____ . . .. . . . _ _ 7 378 3S6 (94%):~ ~295 (78~) o 8 ~04 ~ 375~(93%)~:~ ~ 297 (74%j ~ 9 429 406~(95%~ ~333 ~78%): ~:
. ~ _ _ ~ _ ____ __ ~ 10 412 ~ ~378~ (92%)~ ~ 302 (~73%~):
u~ . ~ - :: - :
ll 522 478 (9~%): ~ :~;374 (72%) ~ ~ ~
2 339 ~ 317~(94%) ~ 250 ~(74~ : ~ ~ :
13 352 326 (9~3%) ~ ~260~(74~) 1 518 432 ~(~83~%):~:~~:~341~(66%) :
o o . ~ ~ -.
2 522 : 4~4 (85%): ~ :~-339~(65%) a) ~ - .,.
3 510 426 (84%) ~ ~ 34~6~(68~) ` ~
o 4 : 150 ~ 139~(93%)~ ~ :121;(81%)~ :: :
_ _ _ _ n~ . _ : : , : :: :
As is clear from Tables 1 and 2, each of the samples for comparison Nos. 1 to 3, which have a low silicoll content outside the scope of the present invention, has a Brinell hardness at a temperature of 300C within a range of from 83 to 85% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400C within a range of from 65 to 68% of its room-temperature Brinell hardness, both of which are lower than the target values in the present invention. The sample for comparison No. 4, which has a low carbon content outside the scope of the present invention, has a room-temperature Brinell hardness of 150, which is far lower than the target value in the present lnvention.
Each of the samples of the invention Nos. 1 to :
13 has, in contrast, a Brinell hardness at a room-temperature withln a range~of from 304 to 522, which lS
higher than the target value in the present invention, and has a Brinell ha~rdness at a temperature of 300C of at least 90% of its room-temperature Brinell hardness, which is the target ~alue in the present invention, and has a Brinell hardnèss at a temperature 400~C of at least ?~ of its room temperature Brinell hardness, which is the tar~et value in the present invention. ~
Thus, each~of the sampies of the invention Nos. 1 to 13 has an~exceller.t w~ar~ resistance in the intermediate tempernture rec.lon without largely increasing its room-. .
.
- .
.. . . . . . .
~3~87~
temperature hardness.
According to the present invention, as described abc.ve in detail, ~.t is possible to obtain a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, and has a srinell hardness at a temperature of 300C of at least 90% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400C of at least 70~ of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely increasing its room-temperature Brinell hardness, thus providing lndustrially useful effects.
`: ' - : :
::
;
, ,, :: : : : :
: .
:
2~4 -~
` ' ' - . : -' : ' ', ,' ', ` ~ . ' , , ' ' ' ,
Boron has a Eunction of improving~hardenability o~
steel with a slight content. In;the~wear-resl$tant~steel of the present invention, thereore,~boron;is additionally added as required. However, with a boron content of under 0.0003 wt.~, a desired effect as mentioned above is not available. With a boron;content~of over O.O100 ~O wt.~, on the other hand, weldability and hardenability of~
steel are degraded. ~The boron~;-ontent should~therefore be limi.ted within a range~of ~rom 0.00~03~to 0.OlOU wt.%;.
~9) Niobium~
~iobium has a iunc-ion Gf impro-i~n~ bardnes6 of ~ ;
16~
,, ,: . : ~: . ~:
:, . .
7 ~
steel through precipitation hardening. In the wear-resistant steel of the present invention, therefore, niobium is additionally a~ded as rPquired. ~owever, with a niobium content of under 0.005 wt.%, a desired effect as mentioned above is not available. With a niobium content of over 0.100 wt.~, on the other hand, weldability of steel is degraded. The niobium content should therefore be limited within a range of from 0.005 to 0.100 wt.%.
(10) Vanadium Similarly to niobium, vanadium has a function of improving hardness of steel through precipitation hardening.
In the wear-resistant steel of the present invention, therefore, vanadium is additionally added as required.
However, with a vanadium coDtent of under 0.01 wt.%, a desired effect as mentioned above is not available.
With a vanadium content of over 0.10 wt.~, on the other hand, weldability of steel is degraded. The vanadium content should therefore be limited within a range of ~xom 0.01 to O.lQ wt.~.
: ~
(11) Titanium~ ~
Similai-ly to n~obium, itanium has a function of improving ha~dness Or steel through precipi~atlon hardening. In the wear-resistant steel of the present :
invention, therefore, titaniw,l is additionally added as required. Howeve~^, with a titanium content of under ~ - 17 -7 ~
0.005 wt.~, a desired effect as mentioned above is not available. With a titanium content of over 0~100 wt.%, weldability of steel i5 degraded. The titanium content should therefore be lim.ited within a range of from 0.005 to 0.100 wt.%.
In the present invention, for example, a slab of a wear-resistant steel having the above-mentioned chemical composition may be hot-rolled to prepare a steel sheet, and the thus prepared steel sheet may be subjected to heat treatments including a hardening treatment,~ a tempering treatment, an ageing treatment and a s~ress relieving treatment. Hardness~ and toughness of the steel sheet can further be improved by the~application of these heat treatments thereto. ;~
Now, the wear-reslstant steel of the present invention is described more in~detail by means of examples while comparing with a wear-resistant steel for comparison outside the scope of the present l~nVentlon.
EXA~SPLES
Ingots of the wear-resistant steel of the present invention havlng the chemical compositions withln the ~
scop~ of the present ir.ventlon as shown in Table l, an~d ingots of a wear-resistant steel for comparison having the chemical composltions outslde the s~ope of ~he :- 18 ~
:
: ~: .
~3~87~
present invention as shown also in Table 1, were melted in a melting .l`urnace, and then cast into slabs. The resultant slabs were then hot-rolled to prepare samples of the wear-resistant steel of the present invention (herein-after referred to as the "samples of the invention") Nos. 1 to 13 having a thickness of 15 mm, and samples of the wear-resistant steel for comparison outside the scope of the present invention (hereinafter referred to as the "samples for comparison") Nos. 1 to 4 also having a thickness of 15 mm.
The samples of the invention Nos. 1 to 4 and 6 to 13, and the samples for comparison Nos~ 1 to 3 were subjected to any one of the following heat treatments as shown in the column of "heat treatment" in Table l.~ The sample of the invention No. 5;and~the sample for comparison No. 4 were maintained in~the~as-rolled state without being subjected to any heat treatment. ~ ~
(1) A sample is hardened by heating the sample to a temperature of 900C and then water-quenching the heated sample from the above-mentioned temperature (hereinafter, this heat treatm~nt being referred to as the "RQ")i (j) A sample is subjected:to the~above-mentio4ed RQ, and then tempered at a temperature as shown in the parentheses in the column of "heat t.reatment" in Table 1 , (hereinafter, thls heat~treatment being referred to as 19 -; ~
-- - . : . , ~ - ' ~ , :,: , 8~
the "RQT");
t3) A sample is directly hardened by immediately water-quenching the samp~e from the hot-rolling finishing temperature (hereinafter, this heat treatment being referred to as the "nQ"); and (4) A sample is subjected to the above-mentioned DQ, and then tempered at a temperature as shown in the paren-theses in the column of "heat treatment" in Table l (hereinafter, this heat treatment being referred to as the "DQT").
Then, for each of the samples of the invention Nos. l to 13 and the samples for comparison Nos, l to 4, a Brinell hardness (HB) at a room-temperature, a Brinell hardness at a temperature of 300C and a Br1ne11 hardness at a temperature of 400C were investigated. ~ThP results are shown in ~able 2. In the column of "Brinell hardness (HB)" in Table 2, the values of Brinell hardness shown in the subcolumns oE "at 300C" and "at 400-C" were~
obtain~d by converting the values measured in the tensile 2Q test, although the values of Brinell hardness showr. In the subcolumn of "at room-temperature" were obtained by means of the Brinell test. Each va1ue of percentages shown in~the parentheses in the subcolumns of "at 300C"
~ and "at 400~C"~presents a ratio of each value of Brinell hardnesses ~at temperatures of 300C and 400C to a value of its Brinell hardness at a room-temperature.
' .
.J ~ ~ ~ ~ a _ u o ~ a o ~1~ a a ~ _ ~ ~ _ _ _ _ ~ E~ ._ C~ _ _ _ _ _ _ Ql Ql a) Ql ~1) Q) C) Ql 5) a) Ql a) (U IU a~ a) ~1) r r-l r I r-l r1 r1 r-l r1 r~ r1 r-J r-l r-l r-l r l r~ r-l rl r _ _ _ J __ _ . O O O O O _ __ _ r _ ~ l l l l l l ~ O l l O O l l l c l _ _ _ _ _ _ _ _ N U~ _ O O ~ _ _ O _ ,~0 ~ ~ ~
r t.l _ _ _ _ O O O _ _ _ O O _ _ _ O _ ~LI~ t~t~ i O~ 1~1 O r-l ~ ~ O r-l O O O ~1 O rl ~ rl ~ 1~ CO CO I~ I_ ~_ 1~ ~ G ~r 1~ U~ It~ 1~ 1~ 1~ t--_ O O O O O O O ~ r-l O r-l _ O O O O
N ~ ~ ~1 ~ C~ N N C O ~) ~1 CO ~D ~ r l N r 1 r O r: N r~ r~ r-l r-l r-l O~ O O r; O N O O r1 _ ~ _ --- - -1- - -- -- - ~
~ ,.o~ o ~r ~ ~ 1 O O O u~
r1 N l r ¦ N r-l r1 ¦ N ¦ (`'1 ~¦
L~ uo~uaJ~u~ a~ 30 aldwes uosl~edwo -- 21 -- .
.
8 ~ ~
Table 2 _ ~
Brinell hardness (HB) ~o . . . ~ __ . __ ._ _ _ At room- At 300CAt 400C
m~ _. _ . __ _ 1518 477 (92%)383 (74%) _ ._ _.
. 2481 ~ 441 (92%)361 (75%) 3510 477 ~94%)448 (88%) , o 449g 461 (92%)388 (78~) .~ _ 5304 280 (92%)221 (73%3 ~ _ :
.~ 6522 495 -(g5%)~395 ~76%) _ . . ____ . . .. . . . _ _ 7 378 3S6 (94%):~ ~295 (78~) o 8 ~04 ~ 375~(93%)~:~ ~ 297 (74%j ~ 9 429 406~(95%~ ~333 ~78%): ~:
. ~ _ _ ~ _ ____ __ ~ 10 412 ~ ~378~ (92%)~ ~ 302 (~73%~):
u~ . ~ - :: - :
ll 522 478 (9~%): ~ :~;374 (72%) ~ ~ ~
2 339 ~ 317~(94%) ~ 250 ~(74~ : ~ ~ :
13 352 326 (9~3%) ~ ~260~(74~) 1 518 432 ~(~83~%):~:~~:~341~(66%) :
o o . ~ ~ -.
2 522 : 4~4 (85%): ~ :~-339~(65%) a) ~ - .,.
3 510 426 (84%) ~ ~ 34~6~(68~) ` ~
o 4 : 150 ~ 139~(93%)~ ~ :121;(81%)~ :: :
_ _ _ _ n~ . _ : : , : :: :
As is clear from Tables 1 and 2, each of the samples for comparison Nos. 1 to 3, which have a low silicoll content outside the scope of the present invention, has a Brinell hardness at a temperature of 300C within a range of from 83 to 85% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400C within a range of from 65 to 68% of its room-temperature Brinell hardness, both of which are lower than the target values in the present invention. The sample for comparison No. 4, which has a low carbon content outside the scope of the present invention, has a room-temperature Brinell hardness of 150, which is far lower than the target value in the present lnvention.
Each of the samples of the invention Nos. 1 to :
13 has, in contrast, a Brinell hardness at a room-temperature withln a range~of from 304 to 522, which lS
higher than the target value in the present invention, and has a Brinell ha~rdness at a temperature of 300C of at least 90% of its room-temperature Brinell hardness, which is the target ~alue in the present invention, and has a Brinell hardnèss at a temperature 400~C of at least ?~ of its room temperature Brinell hardness, which is the tar~et value in the present invention. ~
Thus, each~of the sampies of the invention Nos. 1 to 13 has an~exceller.t w~ar~ resistance in the intermediate tempernture rec.lon without largely increasing its room-. .
.
- .
.. . . . . . .
~3~87~
temperature hardness.
According to the present invention, as described abc.ve in detail, ~.t is possible to obtain a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, and has a srinell hardness at a temperature of 300C of at least 90% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400C of at least 70~ of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely increasing its room-temperature Brinell hardness, thus providing lndustrially useful effects.
`: ' - : :
::
;
, ,, :: : : : :
: .
:
2~4 -~
` ' ' - . : -' : ' ', ,' ', ` ~ . ' , , ' ' ' ,
Claims (4)
1. A wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, a Brinell hardness at a temperature of 300°C of at least 90%
of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness, characterized by consisting essentially of:
carbon : from 0.08 to 0.40 wt.%, silicon : from 0.8 to 2.5 wt.%, manganese : from 0.1 to 2.0 wt.%, and the balance being iron and incidental impurities.
of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness, characterized by consisting essentially of:
carbon : from 0.08 to 0.40 wt.%, silicon : from 0.8 to 2.5 wt.%, manganese : from 0.1 to 2.0 wt.%, and the balance being iron and incidental impurities.
2. A wear-resistant steel for the intermediate and room temperature service as claimed in Claim 1 wherein:
said wear-resistant steel additionally contains at least one element selected from the group consist-ing of:
copper : from 0.1 to 2.0 wt.%, nickel : from 0.1 to 10.0 wt.%, chromium : from 0.1 to 3.0 wt.%, molybdenum : from 0.1 to 3.0 wt.%, and boron : from 0.0003 to 0.0100 wt.%,
said wear-resistant steel additionally contains at least one element selected from the group consist-ing of:
copper : from 0.1 to 2.0 wt.%, nickel : from 0.1 to 10.0 wt.%, chromium : from 0.1 to 3.0 wt.%, molybdenum : from 0.1 to 3.0 wt.%, and boron : from 0.0003 to 0.0100 wt.%,
3. A wear-resistant steel for the intermediate and room temperature service as claimed in Claim 1, wherein:
said wear-resistant-steel additionally contains at least one element selected from the group consist-ing of:
niobium : from 0.005 to 0.100 wt.%, vanadium : from 0.01 to 0.10 wt.%
and titanium : from 0.005 to 0.100 wt.%.
said wear-resistant-steel additionally contains at least one element selected from the group consist-ing of:
niobium : from 0.005 to 0.100 wt.%, vanadium : from 0.01 to 0.10 wt.%
and titanium : from 0.005 to 0.100 wt.%.
4. A wear-resistant steel for the intermediate and room temperature service as claimed in Claim 3, wherein:
said wear-resistant steel additionally contains at least one element selected from the group consist-ing of:
copper : from 0.1 to 2.0 wt.%, nickel : from 0.1 to 10.0 wt.%, chromium : from 0.1 to 3.0 wt.%, molybdenum : from 0.1 to 3.0 wt.%, and boron ; from 0. 0003 to 0. 0100 wt.%.
said wear-resistant steel additionally contains at least one element selected from the group consist-ing of:
copper : from 0.1 to 2.0 wt.%, nickel : from 0.1 to 10.0 wt.%, chromium : from 0.1 to 3.0 wt.%, molybdenum : from 0.1 to 3.0 wt.%, and boron ; from 0. 0003 to 0. 0100 wt.%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3743190A JPH03243743A (en) | 1990-02-20 | 1990-02-20 | Wear-resistant steel for ordinary and medium temperature use having high hardness in medium and ordinary temperature range |
| JP2-37431 | 1990-02-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2034874A1 true CA2034874A1 (en) | 1991-08-21 |
Family
ID=12497328
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2034874 Abandoned CA2034874A1 (en) | 1990-02-20 | 1991-01-24 | Wear-resistant steel for intermediate and room temperature service |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0445519A1 (en) |
| JP (1) | JPH03243743A (en) |
| AU (1) | AU7107891A (en) |
| CA (1) | CA2034874A1 (en) |
| FI (1) | FI910727A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5131965A (en) * | 1990-12-24 | 1992-07-21 | Caterpillar Inc. | Deep hardening steel article having improved fracture toughness |
| US5366568A (en) * | 1993-10-13 | 1994-11-22 | Bruce Douglas G | Method of producing primarily tempered martensite steel |
| CN1293222C (en) * | 2003-12-11 | 2007-01-03 | 杨军 | Easy cut by flame abrasion-resistant steel in high rigidity, in toughness and preparation method |
| US8684235B2 (en) | 2007-02-14 | 2014-04-01 | Kao Corporation | Trigger-type liquid sprayer |
| TWI341332B (en) | 2008-01-07 | 2011-05-01 | Nippon Steel Corp | Wear-resistant steel sheet having excellent wear resistnace at high temperatures and excellent bending workability and method for manufacturing the same |
| JP6459875B2 (en) * | 2015-09-25 | 2019-01-30 | Ｊｆｅスチール株式会社 | Abrasion-resistant steel plate and method for producing the same |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH317544A (en) * | 1956-06-07 | 1956-11-30 | Monteforno Acciajerie E Lamina | Structural steel |
| US2863763A (en) * | 1957-03-19 | 1958-12-09 | Samuel J Rosenberg | Ductile and tough high strength steel |
| SU266215A1 (en) * | 1968-01-09 | 1970-03-17 | Чел бинский ордена Ленина завод дорожных машин Колющенко | |
| GB1202513A (en) * | 1969-01-15 | 1970-08-19 | Stoody Co | Process of forming a layer of added steel to a steel workpiece |
| SU342941A1 (en) * | 1970-01-20 | 1972-06-22 | М. П. Браун, И. Н. Попов , Э. И. Мировский | |
| JPS5442812A (en) * | 1977-09-12 | 1979-04-05 | Nat Jutaku Kenzai | Method of constructing building |
| JPS5565350A (en) * | 1978-11-10 | 1980-05-16 | Mitsubishi Heavy Ind Ltd | High toughness, wear resistant steel |
-
1990
- 1990-02-20 JP JP3743190A patent/JPH03243743A/en active Pending
-
1991
- 1991-01-24 CA CA 2034874 patent/CA2034874A1/en not_active Abandoned
- 1991-01-28 EP EP91101082A patent/EP0445519A1/en not_active Withdrawn
- 1991-02-14 FI FI910727A patent/FI910727A/en unknown
- 1991-02-15 AU AU71078/91A patent/AU7107891A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| FI910727A0 (en) | 1991-02-14 |
| JPH03243743A (en) | 1991-10-30 |
| EP0445519A1 (en) | 1991-09-11 |
| FI910727A (en) | 1991-08-21 |
| AU7107891A (en) | 1991-08-22 |
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