CA1130617A - Silicon alloyed steel - Google Patents
Silicon alloyed steelInfo
- Publication number
- CA1130617A CA1130617A CA319,150A CA319150A CA1130617A CA 1130617 A CA1130617 A CA 1130617A CA 319150 A CA319150 A CA 319150A CA 1130617 A CA1130617 A CA 1130617A
- Authority
- CA
- Canada
- Prior art keywords
- steel
- heat treatment
- steel according
- residual austenite
- microstructure
- 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.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 38
- 239000010959 steel Substances 0.000 title claims abstract description 38
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 8
- 239000010703 silicon Substances 0.000 title claims abstract description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract 4
- 239000012535 impurity Substances 0.000 claims abstract 2
- 229910052742 iron Inorganic materials 0.000 claims abstract 2
- 229910001566 austenite Inorganic materials 0.000 claims description 19
- 238000005275 alloying Methods 0.000 claims description 14
- 229910001563 bainite Inorganic materials 0.000 claims description 9
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 8
- 239000011651 chromium Substances 0.000 claims description 6
- 239000011572 manganese Substances 0.000 claims description 6
- 239000010955 niobium Substances 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052758 niobium Inorganic materials 0.000 claims description 4
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052748 manganese Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims 2
- 229910052782 aluminium Inorganic materials 0.000 claims 2
- 229910052750 molybdenum Inorganic materials 0.000 claims 2
- 239000011733 molybdenum Substances 0.000 claims 2
- 230000009977 dual effect Effects 0.000 claims 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 abstract 1
- 230000015572 biosynthetic process Effects 0.000 description 5
- 229910000617 Mangalloy Inorganic materials 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910000677 High-carbon steel Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- FXNGWBDIVIGISM-UHFFFAOYSA-N methylidynechromium Chemical compound [Cr]#[C] FXNGWBDIVIGISM-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000005482 strain hardening Methods 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
- C21D1/20—Isothermal quenching, e.g. bainitic hardening
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Laminated Bodies (AREA)
Abstract
ABSTRACT
High strength steel is produced with a bainitic-austentitic microstructure, obtained by isothermal heat treatment. The steel contains (in weight percentages) 0.8% to 1.2% carbon, 2.0% to 2.6% silicon, 0.3% to 1.0% manganese, the remainder consisting of iron and normal impurities. The steel has good strength and toughness properties which render it useful in wearing parts subjected to heavy impacts.
High strength steel is produced with a bainitic-austentitic microstructure, obtained by isothermal heat treatment. The steel contains (in weight percentages) 0.8% to 1.2% carbon, 2.0% to 2.6% silicon, 0.3% to 1.0% manganese, the remainder consisting of iron and normal impurities. The steel has good strength and toughness properties which render it useful in wearing parts subjected to heavy impacts.
Description
Silicon alloyed steel The present invention relates to Si-alloyed high carbon steel, which by isothermal heat treatment o~tains particularly advan-tageous strength and toughness properties and which is useful especially in wearing parts subjected to heavy impacts.
For such wearing parts it is generally known to use Mn-alloyed austenitic steel, so~called Hadfield steel, when, in addition to a~rasion resistance, toughness is required of the part, If toughness is not necessary~ it is possihle to use e.g.
high carbon chromium allo~ed steels (1,0 % C, 12 % Cr). Both such steels have several dra~backs~ Hadfield steel (1,0 % C, 13 % Mn) is difficult to manufacture, it can only be formed by casting and its corrosion resistance and weldability are poor. Due to the high Mn~alloy content, this steel is also expensive.
High carbon chromium steels, on the other hand, are brit-tle and their workability is poor. They are also expensive due to high alloy content.
The advantageous mechanical properties of the steel according - 20 to the present invention are based on the bainitic-austenitic dual-phase microstructure o~tained in the isothermal heat treatment, The bainitic component of the microstructure gives the steel good initial hardness and rich residual austenite gives it strong strain hardening capacity.
- In the present steel, advantage has been taken of a known effect of silicon to prevent carbide formation. By increasing the silicon content of a high carbon steel up to 2,0 - 3,0 ~, carbide formation can be prevented during isothermal decom-position of austenite at a suitable temperature~
The use of silicon as an alloying element is known e.g. in spring steels wherein C- and Si-contents are generally Cc0~8 Si~2,o %. In these steels, Si-alloying is generally used as ` ~
., :
, ~(1617 an alloying element increasing hardenability and tempering resistance.
Generally known are also low carbon high Si-alloyed steels (C < 0 ~1 % ~ Si~V 2 r - 4~0 %~ which are used as core plates of electromagnets.
The purpose of Si~alloying is to prevent the formation of carbide (cementite~,, when after the austenitizing the steel is allowed to decompose isothermally to upper bainite within a temperature range of 3sa - 45QC or to lower bainite within the temperature range of 280 - 350C, Thus, the obtained bainitic ferrite only contains ~0,01 % of carbon. With car-bide formation prevented, carbon must diffuse into the re-maining austenite as the bainite reaction proceeds. This, on the other hand~ increases the stability of austenite with increasing carbon content. If for example the carbon content of a steel is 1, a ~ and it decomposes to 50 ~ bainite without carbide formation, the carbon content of residual austenite increases to appr. 2 %. Thus, by controlling the composition (C- and Si-content) of the steel, decomposition temperature 20 and holdingtime, it is possible to control the bainite-austenite ratio obtained as a result of the decomposition of austenite.
The following examples illustrate mechanical properties obtained with the steel according to the invention.
The chemical compositions of the example steels are presented in table 1.
, ~, Steel C Si Mn C~ Ni Cu ~ll C~Si % %. % % % % % %
1 0~8Q 2~07 0,48 0,24 0,11 0,16 0,033 2,87
For such wearing parts it is generally known to use Mn-alloyed austenitic steel, so~called Hadfield steel, when, in addition to a~rasion resistance, toughness is required of the part, If toughness is not necessary~ it is possihle to use e.g.
high carbon chromium allo~ed steels (1,0 % C, 12 % Cr). Both such steels have several dra~backs~ Hadfield steel (1,0 % C, 13 % Mn) is difficult to manufacture, it can only be formed by casting and its corrosion resistance and weldability are poor. Due to the high Mn~alloy content, this steel is also expensive.
High carbon chromium steels, on the other hand, are brit-tle and their workability is poor. They are also expensive due to high alloy content.
The advantageous mechanical properties of the steel according - 20 to the present invention are based on the bainitic-austenitic dual-phase microstructure o~tained in the isothermal heat treatment, The bainitic component of the microstructure gives the steel good initial hardness and rich residual austenite gives it strong strain hardening capacity.
- In the present steel, advantage has been taken of a known effect of silicon to prevent carbide formation. By increasing the silicon content of a high carbon steel up to 2,0 - 3,0 ~, carbide formation can be prevented during isothermal decom-position of austenite at a suitable temperature~
The use of silicon as an alloying element is known e.g. in spring steels wherein C- and Si-contents are generally Cc0~8 Si~2,o %. In these steels, Si-alloying is generally used as ` ~
., :
, ~(1617 an alloying element increasing hardenability and tempering resistance.
Generally known are also low carbon high Si-alloyed steels (C < 0 ~1 % ~ Si~V 2 r - 4~0 %~ which are used as core plates of electromagnets.
The purpose of Si~alloying is to prevent the formation of carbide (cementite~,, when after the austenitizing the steel is allowed to decompose isothermally to upper bainite within a temperature range of 3sa - 45QC or to lower bainite within the temperature range of 280 - 350C, Thus, the obtained bainitic ferrite only contains ~0,01 % of carbon. With car-bide formation prevented, carbon must diffuse into the re-maining austenite as the bainite reaction proceeds. This, on the other hand~ increases the stability of austenite with increasing carbon content. If for example the carbon content of a steel is 1, a ~ and it decomposes to 50 ~ bainite without carbide formation, the carbon content of residual austenite increases to appr. 2 %. Thus, by controlling the composition (C- and Si-content) of the steel, decomposition temperature 20 and holdingtime, it is possible to control the bainite-austenite ratio obtained as a result of the decomposition of austenite.
The following examples illustrate mechanical properties obtained with the steel according to the invention.
The chemical compositions of the example steels are presented in table 1.
, ~, Steel C Si Mn C~ Ni Cu ~ll C~Si % %. % % % % % %
1 0~8Q 2~07 0,48 0,24 0,11 0,16 0,033 2,87
2 Q,78 2,45 0,55 0,07 0,07 0,01 0,034 3,23
3 Q,93 2,33 0,48 0,03 a,01 0,01 0,030 3,26
4 0,g8 2,49 0~51 0,02 0,01 Q,01 0,030 3,47 0,80 2,40 0,52 0,7g 0,01 0,01 0,035 2,91 The test steels were heat treated as .~ollows: austenitizing 92Q ~ 1030C~ lQ min ~ isothermal bainitizing at 380C, 350C
or 320C, water cooling, The test specimen were subjected to tensile tests performed with an ~ 8 mm tensile test specimen, to impact tests (KV~ and residual austenite content was determined with X-ray measurements. Test results are lllus-trated in table 2.
.
., ~.
13 ~30617 rl ~ 0 ~ O ~ al O ¦ ~ O ~ O
. O ~I O (~I O ~I O ~`I ~) ~ (~1 11 11 11 11 11 11 11 11 11 11 11 11m ~ . ~ ~ ~ .1~ ~ -~
~D In a:~ ~ ~ o o o L~'~
Cl~ ~ O ) C~ r~ co ~ ~ ~ ~' ~:: Z . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ U~ Ul .
. .
~,~, . : .
~ O ~ ~ r- ~ Oo ~ 0~ 1~ o ~r ~
C,) . ~ .
. O o ~ o o ~ o o o o K ~ I~ . In ,~~ ~, ~ ~D~ o ~ ~
. u~ ~n o o m o ~ u~~ ~D U) ~
oo ~ Lr ~~ ~ ~ ~oo co r~ t~' - ~ o~P ~ ~) N ~)~I ~1 ~ r I~) ~
O O ~ ~1O O 1~ a)N ~5) 1~ o , IS) O 1~ t~ ~:>Cl~ Il ) ~ ~ ~ O (~ ~
~¢ o~o r~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
.
. . .
00 ~ o Ln ~ ~ Ln o ~ ~ ~9 ~
~D ~ ~D ~ ~ O O ~r o r~ ~ ~ .~ ~ ~ ~ I~ r~
~ Z ~1 ~ ~ ~ ~ ~ ~ ~ ~ ~1 ~ ~
~ . , ' o ~ o Ln Ln L ) 1- r~ o o . ~ c~ ~ Ln ` ~ ~I ~ C~\ Ul ~1 ~ o~ o~) ~ ~ ~1 O ~Y .
z o o o~ ~ oo ~) ~ J ~1 ~1 _._ ~ , __ . ., _. _,___ _~ .
,o O O O O 'O .
oo CO~o ~o Ln t~ O , ~) ~ Ir) ~) ~ ~r _ ____ ._ _ .__. _~ . _ _ _.. _____._. .. ~ ...... __.. _ . .. _ .. _._.
~ .
. ~ ' . ~ Ln Ln .. ..
. - ~ . ~, -.
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36~7 By comparing the strength and toughness values obtained with residual austenite contents~ it can be seen that the ~est com,~inations of properties are accomplished with t~e residual austenite content ~etween 30 - 40 %, Thus~ the yield strength will be Rp o 2 7 850 N~mm2 and the tensile strength Rm ~1300 N/~m2 when the isothermal bainitizing temperature is 380C. Lowering the bainitizing temperature ~elow 350C
increases the strength of the steel considerably. The bain-itizing time will be then longer and the microstructure ob-tained is lower bainite, Elongation to fracture A5 ~ 20 ~.
; Too low a C + Si-content leads to too small an amount of residual austenite, stronger but more brittle bainite con-trolling the properties. This is the case with the example steel 1, so C + Si must be ~2,80.
Too high a C + Si-content, on the other hand, leads to too high a residual austenite content. Thus the residual austenite is too much in control of mech'anical properties, the strength thus remaining lower. Thus, the res,idual austenite is also mechanically more unstable which impairs the elongation to fracture. This is the case with the example steel 4, so C + Si must be c 3,5.
According to the test results, the most suitable range for the sum is C + Si = 2,90 - 3,40 ~, however with C ~ 0,8 % and Si 2 2,0 ~.Thus the elongation to fracture A5 is 30 -- 40 ~ and consists mainly of uniform elongation which is an indication of strain hardening capacity found only in austenitic Hadfield manganese steel and staïnless steels. However, in unworked condition, yield strength of ~oth of these steels is ~50 %
of the yield strength of the steel of the present invention.
In order to improve its heat treatment properties, the steel according to the invention can be alloyed with austenite stabilizing alloying elements, such as manganese and nickel, up to appr. 1 ~. Thus for the C-content, it is necessary to take into account the effect of the additional alloying - : ~" ~ ~
~L~.30617 on the stability of austenite, ~lso carbide forming chromium and niobium can be used in alloying~ The former improves hardenabilit~ on large bar diameters and it can be used in : amounts5~ 1 %r preferably ~a~s %~ Niobium, on the other hand, can be used to control grain growth properties, The alloying amount needed for this is C 0,1 ~Al~alloying is preferable for binding of free nitrogen in ferritic bainite which is advantageous for toughness, particularly at low temperatures.
The alloying amount needed for this is ~ 0,1 ~.
The steel according to the invention has produced a combination of strength and toughness properties that has been impossible to obtain with prior art steels. Moreover, since these properties are achieved by simple isothermal heat treatment and inexpensive alloying, the steel according to the invention can be expected to receive wide acceptance and to be widely used in applications requiring high strength and good abrasion resistance.
.
or 320C, water cooling, The test specimen were subjected to tensile tests performed with an ~ 8 mm tensile test specimen, to impact tests (KV~ and residual austenite content was determined with X-ray measurements. Test results are lllus-trated in table 2.
.
., ~.
13 ~30617 rl ~ 0 ~ O ~ al O ¦ ~ O ~ O
. O ~I O (~I O ~I O ~`I ~) ~ (~1 11 11 11 11 11 11 11 11 11 11 11 11m ~ . ~ ~ ~ .1~ ~ -~
~D In a:~ ~ ~ o o o L~'~
Cl~ ~ O ) C~ r~ co ~ ~ ~ ~' ~:: Z . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ U~ Ul .
. .
~,~, . : .
~ O ~ ~ r- ~ Oo ~ 0~ 1~ o ~r ~
C,) . ~ .
. O o ~ o o ~ o o o o K ~ I~ . In ,~~ ~, ~ ~D~ o ~ ~
. u~ ~n o o m o ~ u~~ ~D U) ~
oo ~ Lr ~~ ~ ~ ~oo co r~ t~' - ~ o~P ~ ~) N ~)~I ~1 ~ r I~) ~
O O ~ ~1O O 1~ a)N ~5) 1~ o , IS) O 1~ t~ ~:>Cl~ Il ) ~ ~ ~ O (~ ~
~¢ o~o r~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
.
. . .
00 ~ o Ln ~ ~ Ln o ~ ~ ~9 ~
~D ~ ~D ~ ~ O O ~r o r~ ~ ~ .~ ~ ~ ~ I~ r~
~ Z ~1 ~ ~ ~ ~ ~ ~ ~ ~ ~1 ~ ~
~ . , ' o ~ o Ln Ln L ) 1- r~ o o . ~ c~ ~ Ln ` ~ ~I ~ C~\ Ul ~1 ~ o~ o~) ~ ~ ~1 O ~Y .
z o o o~ ~ oo ~) ~ J ~1 ~1 _._ ~ , __ . ., _. _,___ _~ .
,o O O O O 'O .
oo CO~o ~o Ln t~ O , ~) ~ Ir) ~) ~ ~r _ ____ ._ _ .__. _~ . _ _ _.. _____._. .. ~ ...... __.. _ . .. _ .. _._.
~ .
. ~ ' . ~ Ln Ln .. ..
. - ~ . ~, -.
. .
36~7 By comparing the strength and toughness values obtained with residual austenite contents~ it can be seen that the ~est com,~inations of properties are accomplished with t~e residual austenite content ~etween 30 - 40 %, Thus~ the yield strength will be Rp o 2 7 850 N~mm2 and the tensile strength Rm ~1300 N/~m2 when the isothermal bainitizing temperature is 380C. Lowering the bainitizing temperature ~elow 350C
increases the strength of the steel considerably. The bain-itizing time will be then longer and the microstructure ob-tained is lower bainite, Elongation to fracture A5 ~ 20 ~.
; Too low a C + Si-content leads to too small an amount of residual austenite, stronger but more brittle bainite con-trolling the properties. This is the case with the example steel 1, so C + Si must be ~2,80.
Too high a C + Si-content, on the other hand, leads to too high a residual austenite content. Thus the residual austenite is too much in control of mech'anical properties, the strength thus remaining lower. Thus, the res,idual austenite is also mechanically more unstable which impairs the elongation to fracture. This is the case with the example steel 4, so C + Si must be c 3,5.
According to the test results, the most suitable range for the sum is C + Si = 2,90 - 3,40 ~, however with C ~ 0,8 % and Si 2 2,0 ~.Thus the elongation to fracture A5 is 30 -- 40 ~ and consists mainly of uniform elongation which is an indication of strain hardening capacity found only in austenitic Hadfield manganese steel and staïnless steels. However, in unworked condition, yield strength of ~oth of these steels is ~50 %
of the yield strength of the steel of the present invention.
In order to improve its heat treatment properties, the steel according to the invention can be alloyed with austenite stabilizing alloying elements, such as manganese and nickel, up to appr. 1 ~. Thus for the C-content, it is necessary to take into account the effect of the additional alloying - : ~" ~ ~
~L~.30617 on the stability of austenite, ~lso carbide forming chromium and niobium can be used in alloying~ The former improves hardenabilit~ on large bar diameters and it can be used in : amounts5~ 1 %r preferably ~a~s %~ Niobium, on the other hand, can be used to control grain growth properties, The alloying amount needed for this is C 0,1 ~Al~alloying is preferable for binding of free nitrogen in ferritic bainite which is advantageous for toughness, particularly at low temperatures.
The alloying amount needed for this is ~ 0,1 ~.
The steel according to the invention has produced a combination of strength and toughness properties that has been impossible to obtain with prior art steels. Moreover, since these properties are achieved by simple isothermal heat treatment and inexpensive alloying, the steel according to the invention can be expected to receive wide acceptance and to be widely used in applications requiring high strength and good abrasion resistance.
.
Claims (5)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. High strength steel provided with a bainitic-austenitic micro-structure which is accomplished by isothermal heat treatment, characterized in that the steel contains various alloying elements in the following ranges expressed as weight percentage;
Carbon (C) 0.8 --- 1.2%
Silicon (Si) 2.0 --- 2.6%
Manganese (Mn) 0.3 --- 1.0%
Chromium (Cr) 0 --- 1.0%
Nickel (Ni) 0 --- 1.0%
Niobium (Nb) 0 --- 0.1%
Aluminum (Al) 0 --- 0.1%
Molybdenum (Mo) 0 --- 0.5%
the remainder consisting of iron and normal impurities,
Carbon (C) 0.8 --- 1.2%
Silicon (Si) 2.0 --- 2.6%
Manganese (Mn) 0.3 --- 1.0%
Chromium (Cr) 0 --- 1.0%
Nickel (Ni) 0 --- 1.0%
Niobium (Nb) 0 --- 0.1%
Aluminum (Al) 0 --- 0.1%
Molybdenum (Mo) 0 --- 0.5%
the remainder consisting of iron and normal impurities,
2. Steel according to claim 1, wherein the alloying sum C + Si =
2.9 --- 3.4%.
2.9 --- 3.4%.
3. Steel according to claim 1, characterized in that it contains one or more of the following alloying elements in the following weight ranges:
Chromium (Cr) 0.01 --- 0.5%
Nickel (Ni) 0.01 --- 0.5%
Niobium (Nb) 0.001 -- 0.05%
Aluminum (Al) 0.001 -- 0.05%
Molybdenum (Mo) 0.3 -- 0.5%
Chromium (Cr) 0.01 --- 0.5%
Nickel (Ni) 0.01 --- 0.5%
Niobium (Nb) 0.001 -- 0.05%
Aluminum (Al) 0.001 -- 0.05%
Molybdenum (Mo) 0.3 -- 0.5%
4. Steel according to claim 1, characterized in that it has been provided with a dual phase microstructure produced by isothermal heat treatment carried out at a temperature of 350 - 450°C, the microstructure mainly consisting of upper bainite and residual austenite and wherein the proportion of residual austenite is 30 ---40%.
5. Steel according to claim 1, characterized in that it contains a dual-phase microstructure obtained by isothermal heat treatment carried out at a temperature of 280 - 350° the microstructure mainly consisting of lower bainite and wherein the proportion of residual austenite is 30 - 40%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI780026A FI780026A (en) | 1978-01-05 | 1978-01-05 | KISELLEGERAT STAOL |
| FI780,026 | 1978-01-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1130617A true CA1130617A (en) | 1982-08-31 |
Family
ID=8511375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA319,150A Expired CA1130617A (en) | 1978-01-05 | 1979-01-04 | Silicon alloyed steel |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0003208A1 (en) |
| CA (1) | CA1130617A (en) |
| DK (1) | DK583778A (en) |
| FI (1) | FI780026A (en) |
| IT (1) | IT1110730B (en) |
| NO (1) | NO790013L (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102006038670B4 (en) * | 2006-08-17 | 2010-12-09 | Federal-Mogul Burscheid Gmbh | High silicon steel material for the production of piston rings and cylinder liners |
| KR101067896B1 (en) * | 2007-12-06 | 2011-09-27 | 주식회사 포스코 | High carbon steel plate with excellent strength and ductility and its manufacturing method |
| EP2410070B1 (en) * | 2008-07-31 | 2014-11-05 | The Secretary Of State For Defence | Bainite steel and methods of manufacture thereof |
| WO2011023988A2 (en) * | 2009-08-24 | 2011-03-03 | The Secretary Of State For Defence | Armour |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1924099A (en) * | 1931-11-20 | 1933-08-29 | United States Steel Corp | Thermally hardening steel |
| CH311324A (en) * | 1952-03-12 | 1955-11-30 | Gussstahlwerk Witten Aktienges | Process for producing a workpiece from a steel alloy. |
| FR1286077A (en) * | 1961-01-20 | 1962-03-02 | Renault | Steel and treatment to obtain parts with a high thermal expansion coefficient |
| DE1558505A1 (en) * | 1967-01-23 | 1970-04-16 | Hilti Ag | Anchoring means |
| US3860457A (en) * | 1972-07-12 | 1975-01-14 | Kymin Oy Kymmene Ab | A ductile iron and method of making it |
-
1978
- 1978-01-05 FI FI780026A patent/FI780026A/en unknown
- 1978-12-28 DK DK583778A patent/DK583778A/en not_active Application Discontinuation
-
1979
- 1979-01-03 NO NO790013A patent/NO790013L/en unknown
- 1979-01-04 EP EP79850001A patent/EP0003208A1/en not_active Ceased
- 1979-01-04 CA CA319,150A patent/CA1130617A/en not_active Expired
- 1979-01-05 IT IT19100/79A patent/IT1110730B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| DK583778A (en) | 1979-07-06 |
| NO790013L (en) | 1979-07-06 |
| FI780026A (en) | 1979-07-06 |
| EP0003208A1 (en) | 1979-07-25 |
| IT7919100A0 (en) | 1979-01-05 |
| IT1110730B (en) | 1986-01-06 |
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