CN107779759B - Boron-containing bainite steel rail with excellent delayed fracture resistance and production method thereof - Google Patents
Boron-containing bainite steel rail with excellent delayed fracture resistance and production method thereof Download PDFInfo
- Publication number
- CN107779759B CN107779759B CN201610737596.2A CN201610737596A CN107779759B CN 107779759 B CN107779759 B CN 107779759B CN 201610737596 A CN201610737596 A CN 201610737596A CN 107779759 B CN107779759 B CN 107779759B
- Authority
- CN
- China
- Prior art keywords
- steel
- rail
- bainite
- cooled
- delayed fracture
- 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.)
- Active
Links
- 229910001563 bainite Inorganic materials 0.000 title claims abstract description 45
- 230000003111 delayed effect Effects 0.000 title claims abstract description 16
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 13
- 229910000831 Steel Inorganic materials 0.000 title abstract description 69
- 239000010959 steel Substances 0.000 title abstract description 69
- 229910052796 boron Inorganic materials 0.000 title abstract description 15
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 title abstract description 14
- 238000001816 cooling Methods 0.000 claims abstract description 24
- 238000010438 heat treatment Methods 0.000 claims abstract description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 229910052742 iron Inorganic materials 0.000 claims abstract description 4
- 239000004615 ingredient Substances 0.000 claims description 7
- 238000005096 rolling process Methods 0.000 claims description 2
- 238000005098 hot rolling Methods 0.000 abstract description 9
- 238000000034 method Methods 0.000 abstract description 3
- 238000003723 Smelting Methods 0.000 abstract 1
- 238000005266 casting Methods 0.000 abstract 1
- 238000009749 continuous casting Methods 0.000 abstract 1
- 230000009466 transformation Effects 0.000 description 13
- 239000000126 substance Substances 0.000 description 12
- 239000010936 titanium Substances 0.000 description 11
- 239000000203 mixture Substances 0.000 description 10
- 239000000047 product Substances 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 8
- 239000011651 chromium Substances 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000005204 segregation Methods 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- 238000005275 alloying Methods 0.000 description 5
- 229910001567 cementite Inorganic materials 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 5
- 229910000859 α-Fe Inorganic materials 0.000 description 5
- 229910000734 martensite Inorganic materials 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000005457 optimization Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 238000005496 tempering Methods 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 230000005641 tunneling Effects 0.000 description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 229920001296 polysiloxane Polymers 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000003908 quality control method Methods 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000010310 metallurgical process Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 238000009377 nuclear transmutation Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000001568 sexual effect Effects 0.000 description 1
- 235000015170 shellfish Nutrition 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000000844 transformation Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
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
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
- C21D9/06—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails with diminished tendency to become wavy
-
- 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
-
- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention provides a boron-containing bainite steel rail with excellent delayed fracture resistance and a production method thereof, wherein the steel rail comprises the following components in percentage by weight: c ]: 0.18% -0.26%; [ Si ]: 1.30% -1.70%; [ Mn ]: 1.75% -2.15%; [ Cr ]: 0.30% -0.70%; [ Mo ]: 0.15% -0.40%, [ P ] is less than or equal to 0.020%, [ S ] is less than or equal to 0.010%, and [ B ]: 0.0006% -0.0015%, [ Ti ]: 0.01% -0.03%, [ H ]: 0.00017% or less, and the balance of iron and inevitable impurity elements; the production method comprises the steps of smelting, continuous casting, casting blank heating, hot rolling and heat treatment, wherein the heat treatment is that the steel rail is cooled to 700 +/-60 ℃ or 600 +/-60 ℃ in air after hot rolling, then cooled to 300 +/-40 ℃ at the cooling speed of 0.5 ℃/s-4 ℃/s, and then cooled to room temperature in air. The bainite steel rail produced by the method can be applied to railways through on-line heat treatment, and the delayed fracture resistance of the steel is improved.
Description
Technical field
The invention belongs to the field of metal processing more particularly to a kind of boracic bainites with excellent resistance for delayed fracture
Rail.
Background technique
So far from 1970s, the exploitation of bainite rail has had nearly 50 years history.Bainite rail due to
Its excellent application performance and the rail for being known as 21st century.So far, bainite rail application or it is very limited
, the sexual valence that this is largely determined by bainite rail is relatively low, production technology is also unable to satisfy wanting for large-scale industrial production
It asks.
Presently disclosed bainite rail chemical composition ranges are wide, bring difficulty to rail control of product quality.Test
Research shows that: under conditions of continuous air-cooled after rail hot rolling, bainite structure is generally produced by the high, medium and low temperature transformation of austenite
Object is constituted, and when the chemical composition ranges of steel are excessively wide in range, above-mentioned high, medium and low temperature organizational composition ratio and scale will occur more
Big variation, therefore can cause properties of product that biggish fluctuation occurs, it is unfavorable for the stabilization of product quality, is less useful for welding quality
Control.
Bainite rail intensity has reached high-strength (1200MPa) or strong (1400MPa) grade of steel of superelevation is other, to high-strength steel
Speech, delayed fracture resistance ability declines with the raising of intensity, therefore the resistance to delay of high strength bainite steel rail under normal circumstances
Fracture property is lower than pearlite steel rail, is embodied in elongation percentage is relatively low, fatigue crack growth rate is higher etc..Therefore shellfish is improved
The delayed fracture resistance ability of family name's body rail improves steel to the Technological adaptability of existing metallurgical process controlled level, is successfully to produce
Bainite rail has to solve the problems, such as.Delayed fracture be usually as the residual hydrogen in steel it is relatively high caused by, therefore, improve steel
Resistance for delayed fracture mainly realized by controlling residual hydrogen amount, but by the control of residual hydrogen amount to steel below 0.0001%
Metallurgical production brings larger pressure.
Invention " with the damaging bainitic steel rail with high-wearing feature of highly resistance surface fatigue " (application number:
99800029.9) the bainite rail chemical component disclosed is " carbon 0.15%-0.45%, silicon 0.1%-2.00%, manganese
0.20%-3.00%, chromium 0.20%-3.00%, along with one or more elements selected from following elements group: molybdenum
0.01%-1.00%, copper 0.05%-0.50%, nickel 0.05%-4.00%, titanium 0.01%-0.05%, vanadium 0.01%-
0.30%, niobium 0.005%-0.05%, boron 0.0001%-0.0050%, magnesium 0.0010%-0.0100%, calcium 0.0010%-
0.015%.Although " boracic, chemical composition ranges are very wide in range, bring difficulty to rail control of product quality.Invention limit
Determined carbide in steel tissue signature " a kind of bainitic steel rail steel with good resistance to surface fatigue damage and wearability, until
Small part contains bainite structure, it is characterised in that its long axis is in the carbide between 100nm~1000nm in the bayesian
Body tissue one gives between the gross area shared on section is the section 10%~50%."
Invent " improved non-carbide bainitic steel and its production method " (application number: bayesian disclosed in 96192013.0)
The chemical component of body steel includes C0.05-0.50%, Si and/or Al 1.00-3.00%, Mn0.50-2.50%, Cr0.25-
2.50%, Ni0-3.00%, S0-0.025%, W0-1.00%, Mo0-1.00%, Cu0-3%, Ti0-0.10%, V0-
0.50% and B0-0.005%, Fe be remaining and adjoint impurity.Although boracic, chemical composition ranges are very wide in range, give rail product
Quality control brings difficulty.The invention does not propose specific technological parameter yet, and production technology is only proposed " from its rolling temperature
The continuous natural cooling rail to room temperature, or acceleration cools down the rail to room temperature in air ".
Invention " the tough weldable air-cooled great health bainitic steel of the dedicated superelevation of railroad frog " (application number: 98124899.3) open
Bainitic steel chemical component " (Wt%) C0.10-0.6, Si≤2.65, Mn0.50-3.20, Cr0.20-2.80, Ni≤3.50,
Mo≤2.00, remainder are Fe, and are added on its basic ingredient one or two or more kinds of following elements (Wt%): Nb≤
0.20, V≤0.20, Ti≤0.20, Re≤0.10, B≤0.008." production technology is empty after 850 DEG C~1000 DEG C austenitizings
Cold ,≤650 tempering are become a useful person.Tempering is needed after the invention hot rolling and air cooling, production technology is complicated, it is difficult to guarantee that rail quality is stablized
Property.
The content chemical composition ranges that above three invention is opened are wide in range, and bainite rail chemical composition ranges are wide, give steel
Rail control of product quality brings very big difficulty.Under conditions of continuous air-cooled after rail hot rolling, bainite structure is generally by Ovshinsky
The high, medium and low temperature transmutation product of body is constituted, when the chemical composition ranges of steel are excessively wide in range, above-mentioned high, medium and low temperature organizational composition
Larger change will occur for ratio and scale, therefore can cause properties of product that biggish fluctuation occurs, and be unfavorable for the steady of product quality
It is fixed, it is less useful for the control of welding quality.
Summary of the invention
It is an object of the invention to overcome the above problem and insufficient and provide a kind of with excellent resistance for delayed fracture
Boracic bainite rail, bainite rail obdurability after burning optimization on line is superior to hot rolled bainite steel rail, without subsequent time
Fire processing, so that it may be applied on railway.
The object of the present invention is achieved like this:
Within the scope of the chemical composition ranges of steel are limited in reasonably；Alloying element is added and realizes tunneling boring bainite group
The purpose knitted, but alloy total amount is unsuitable excessively high, it is excessively high, increase cost and increases the tendency that excessive martensite is precipitated in steel
With the tendency of element segregation, steel toughness plasticity deteriorates or performance inconsistency is serious, and alloy total amount is too low, is unable to get tunneling boring and is
The bainite rail of bainite structure；Further boron element is limited in: within the scope of 0.0006-0.0015%, avoiding boron member
The adverse effect of plain On Impact Toughness, while the resistance for delayed fracture of steel gets a promotion, the upper limit of the residual hydrogen of steel can be improved to
0.00017%.Therefore alloying element range proposed by the present invention is more accurate.
Design ingredient within the scope of bainite rail after burning optimization on line obdurability be superior to hot rolled bainite steel rail,
Without subsequent tempering, so that it may be applied on railway.
A kind of boracic bainite rail that resistance for delayed fracture is excellent and its production method, the ingredient of the rail is by weight
Percentages are as follows: [C]: 0.18%-0.26%；[Si]: 1.30%-1.70%；[Mn]: 1.75%-2.15%；[Cr]:
0.30%-0.70%；[Mo]: 0.15%-0.40%, [P]≤0.020%, [S]≤0.010%, [B]: 0.0006%-
0.0015%, [Ti]: 0.01%-0.03%, [H] :≤0.00017%, remaining is iron and inevitable impurity element.
It is as follows that present component designs reason:
Carbon is most effective intensified element, thus it is acceptable in engineering under the premise of, content is higher, and cost is lower,
Therefore its content should be improved as far as possible, but no more than 0.26%, martensite proportion is excessively high in steel if more than 0.26%,
The toughness plasticity of steel will receive influence；Its content not preferably less than 0.18% simultaneously, otherwise needs to increase containing for other alloying elements
Amount is to strengthen steel matrix, and cost of alloy is excessively high, and steel grade does not have competitiveness, and carbon content within this range, realizes the good of obdurability
Good matching.
Silicon generally as reinforced ferrite element be added steel in, in this steel, it primarily serve inhibit ε-carbide or
The effect that cementite is precipitated, non-carbide precipitate due to carbon segregation and convert the austenite to temperature lower than room temperature, with remnants
The form of austenite remains.Previous typical bainite is divided into upper bainite and lower bainite, wherein containing in difference
The cementite that position is precipitated, cementite can cause the toughness plasticity of steel to significantly reduce, therefore low-carbon bainite steel answering in engineering
With seldom, only ultra-low carbon bainite is applied.With the addition of element silicon, the cementite in bainitic steel, which is precipitated, to be pressed down
System, the non-carbide bainitic steel toughness plasticity that continuous coo1ing obtains significantly improve.Silicone content is lower than 1.30%, then cannot achieve suppression
The purpose that cementite processed is precipitated, silicone content are higher than 1.70%, and remained austenite content increases in steel and carbon content is too low, residual austenite
The stability of body reduces, and the toughness plasticity of steel equally reduces.
Manganese element is that it is strong to have primarily served phase transformation in this steel than more typical cheap, displaced type solution strengthening element
The effect of change, therefore in order to reduce the cost of alloy of steel, additional amount is bigger.Additional amount is lower than 1.75%, then needs to increase it
The content of his expensive alloying elements, therefore it is both economical for being higher than 1.75%, but additional amount should not also be higher than 2.15%, add
The trend for entering the excessively high then element segregation of amount increases, and another aspect structure property especially toughness plasticity will be substantially reduced.
It needs to control Mn content 2.15% hereinafter, the insufficient portion of harden ability to reduce the trend of segregation
Divide and is usually made up by the way that Cr member is added.
Cr is the harden ability element for significantly improving steel, and suitable Cr is added in steel, and ferrite electrode potential also can be improved, and is promoted
So that the surface of steel is formed fine and close oxidation film, improves its corrosion resistance.Cr content is low, and hardness is insufficient after heat treatment, Cr too high levels,
Increase cost of alloy, therefore, the present invention controls in 0.3%~0.7% range of Cr content.
Molybdenum element is typical postponement perlitic transformation, separates bainite and perlitic transformation C curve, to keep steel easy
It is the alloying element for making rail tunneling boring that can obtain bainite structure under the conditions of hot rolling and air cooling in bainite transformation occurs.
Mo content should be higher than that 0.15% in order to achieve the above objectives, but be sufficient below 0.40%.
Boron: in bainitic steel, since boron is in the enough precipitations for effectively inhibiting pro-eutectoid ferrite of segregation energy, B
With the compound addition of Mo, it can be individually added into than Mo and postpone ferrite and pearlite transformation more significantly, since boron element is added
Amount is less and ferro-boron is cheap, therefore boron element often becomes the first choice of bainitic steel.Largely studies have shown that since boron is in crystalline substance
Boundary's segregation also easily causes the loss of impact flexibility, therefore is just added without boron element when more demanding impact flexibility.When
When boron element is more than 0.0015%, the impact flexibility of bainite rail is decreased obviously, and by boron element be limited in 0.0015% with
When lower, impact flexibility remains at higher level, when B < 0.0006%, does not act on the raising of elongation percentage, therefore, control
[B]: 0.0006%-0.0015%.After joined micro boron element, the resistance for delayed fracture of steel (elongation percentage significantly improves)
It gets a promotion, the upper limit of the residual hydrogen of bainitic steel rail steel can be improved to 0.00017%.
Ti is that fine TiN and TiCN can be precipitated after carrying out trace Ti processing in steel in strong nitride forming element
Son hinders Austenite Grain Growth, refines crystal grain, and another aspect Ti can reduce the formation rate of BN, reduce BN in conjunction with N
Harm, give full play to solid solution B improve hardenability effect.The nitrogen fixation effect of Ti content 0.01-0.03%, Ti are best, and titanium contains
Amount is lower than 0.01%, does not have an effect of fixed nitrogen, and Ti content is higher than 0.03%, fixed nitrogen while also will form coarse Ti (N,
C) non-metallic inclusion reduces purity of steel.
A kind of production method for the boracic bainite rail that resistance for delayed fracture is excellent, including smelting-continuous casting-slab
Heating-hot rolling-heat treatment, the heat treatment are that rail hot rolling is air-cooled to 700 DEG C ± 60 DEG C or 600 DEG C ± 60 DEG C later, it
300 DEG C ± 40 DEG C are cooled to the cooling rate of 0.5 DEG C/s-4 DEG C/s afterwards, is then air-cooled to room temperature.
700 DEG C ± 60 DEG C or 600 DEG C ± 60 DEG C are air-cooled to after rail hot rolling, rail hot rolling and air cooling has been able to inhibit first
The precipitation of eutectoid ferrite, as long as therefore start transition temperature (Bs) or more in bainite, according to environment temperature (environment temperature≤
0 DEG C is air-cooled to 600 DEG C ± 60 DEG C, and environment temperature > 0 DEG C is air-cooled to 700 DEG C ± 60 DEG C) will start fast cooling temperature control compared with
Within the scope of narrow, it can achieve the purpose that limit cooling velocity fluctuation.
It is cooling with the cooling velocity of 0.5 DEG C/s-4 DEG C/s, it is because cooling rate is excessively slow, structure of steel when cooling rate is lower than 0.5 DEG C/s
In have more medium temperature block type transformation and occur, this structure stability is poor, and cooling rate is higher than 4 DEG C/s, martensite institute accounting in steel
Regular meeting increases sharply, and the fracture mechanical property of steel can be caused to deteriorate, therefore, cooling velocity preferably controls between 0.5-4 DEG C/s.
Accelerate cooling final cooling temperature control at 300 DEG C ± 40 DEG C, exactly in order to make to accelerate cooling terminate in bainite transformation
In temperature (Bs-Bf) range, 300 DEG C ± 40 DEG C can further make accelerate cooling termination temperature fall in narrow range it
It is interior, start bainite transformation or transformation amount not yet seldom higher than 340 DEG C or medium temperature bainite proportion is higher, it is unfavorable
In the toughness for improving steel, it is lower than 260 DEG C, bainite cryo tissue, even martensite transfor mation proportion are excessively high, the disruptive force of steel
Penalty is learned, is limited to the cooling temperature range of acceleration is terminated, that is, the formation for avoiding high temperature transformation tissue is also reduced
The formation of low-temperature transformation tissue.So accelerating cooling final cooling temperature control at 300 DEG C ± 40 DEG C.
Above-mentioned process technology scheme by technological specification be limited in one it is relatively narrow and reasonable within the scope of, to make to start
It is cooling with terminate cooling structural state and more tend to consistent, to obtain uniformly tiny bainite structure, guarantee rail quality is steady
It is fixed.The consistency of tissue morphology is then influenced beyond the range.
The beneficial effects of the present invention are the bainite rail designed within the scope of ingredient can be through burning optimization on line
It is applied on railway, and the resistance for delayed fracture of steel gets a promotion.
Specific embodiment
Below by embodiment, the present invention is further illustrated.
The embodiment of the present invention is according to the component proportion of technical solution, including at refining-continuous casting-slab heating-hot rolling-heat
Reason, the ingredient of steel of the embodiment of the present invention are shown in Table 1.The main technologic parameters of steel of the embodiment of the present invention are shown in Table 2.Steel of the embodiment of the present invention
Performance be shown in Table 3.
The ingredient (wt%) of 1 steel of the embodiment of the present invention of table
The main technologic parameters of 2 steel of the embodiment of the present invention of table
The performance of 3 steel of the embodiment of the present invention of table
Claims (1)
1. a kind of boracic bainite rail that resistance for delayed fracture is excellent, which is characterized in that the ingredient of the rail by weight hundred
Divide as follows than counting: [C]: 0.18%-0.26%；[Si]: 1.30%-1.70%；[Mn]: 1.75%-2.15%；[Cr]:
0.30%-0.70%；[Mo]: 0.15%-0.40%, [P]≤0.020%, [S]≤0.010%, [B]: 0.0006%-
0.0015%, [Ti]: 0.01%-0.03%, [H] :≤0.00017%, remaining is iron and inevitable impurity element；It is described
The production method of boracic bainite rail includes smelting-continuous casting-slab heating-hot rolling-heat treatment, and the heat treatment is rail heat
It is air-cooled to 700 DEG C ± 60 DEG C or 600 DEG C ± 60 DEG C after rolling, is cooled to 300 DEG C ± 40 later with the cooling rate of 0.5 DEG C/s-4 DEG C/s
DEG C, then it is air-cooled to room temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610737596.2A CN107779759B (en) | 2016-08-26 | 2016-08-26 | Boron-containing bainite steel rail with excellent delayed fracture resistance and production method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610737596.2A CN107779759B (en) | 2016-08-26 | 2016-08-26 | Boron-containing bainite steel rail with excellent delayed fracture resistance and production method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107779759A CN107779759A (en) | 2018-03-09 |
| CN107779759B true CN107779759B (en) | 2019-05-31 |
Family
ID=61439462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610737596.2A Active CN107779759B (en) | 2016-08-26 | 2016-08-26 | Boron-containing bainite steel rail with excellent delayed fracture resistance and production method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107779759B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110607488A (en) * | 2019-09-02 | 2019-12-24 | 鞍钢股份有限公司 | Online heat treatment steel rail for high-speed railway and manufacturing method thereof |
| CN112276030B (en) * | 2020-10-13 | 2021-11-19 | 攀钢集团攀枝花钢铁研究院有限公司 | High-strength delayed fracture-resistant hot-rolled steel rail and preparation method thereof |
| CN112301200A (en) * | 2020-10-13 | 2021-02-02 | 攀钢集团攀枝花钢铁研究院有限公司 | Steel rail with delayed fracture resistance and preparation method thereof |
| CN117327985B (en) * | 2023-10-24 | 2024-10-29 | 包头钢铁（集团）有限责任公司 | B, ti microalloyed hot rolled bainite rail and manufacturing method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1255949A (en) * | 1998-01-14 | 2000-06-07 | 新日本制铁株式会社 | Bainite type rail excellent in surface fatigue damage resistance and wear resistance |
| CN1978690A (en) * | 2005-12-05 | 2007-06-13 | 鞍钢股份有限公司 | Bainite steel rail with excellent fatigue resistance and production method thereof |
| CN101942616A (en) * | 2010-09-15 | 2011-01-12 | 北京科技大学 | Bainite steel plate with high elongation, high strength and low carbon and production method thereof |
| CN103160736A (en) * | 2011-12-14 | 2013-06-19 | 鞍钢股份有限公司 | High-strength bainite steel rail and heat treatment process thereof |
-
2016
- 2016-08-26 CN CN201610737596.2A patent/CN107779759B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1255949A (en) * | 1998-01-14 | 2000-06-07 | 新日本制铁株式会社 | Bainite type rail excellent in surface fatigue damage resistance and wear resistance |
| CN1978690A (en) * | 2005-12-05 | 2007-06-13 | 鞍钢股份有限公司 | Bainite steel rail with excellent fatigue resistance and production method thereof |
| CN101942616A (en) * | 2010-09-15 | 2011-01-12 | 北京科技大学 | Bainite steel plate with high elongation, high strength and low carbon and production method thereof |
| CN103160736A (en) * | 2011-12-14 | 2013-06-19 | 鞍钢股份有限公司 | High-strength bainite steel rail and heat treatment process thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107779759A (en) | 2018-03-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101153370B (en) | Low-alloy high-strength steel plate capable of being welded at high heat input and manufacturing method thereof | |
| CN110029274A (en) | A kind of 1600MPa grades of High-strength high-plasticity drop stamping steel and preparation method thereof | |
| CN101487101B (en) | Steel for CT70 grade coiled tubing and method of manufacturing the same | |
| CN105543676B (en) | A kind of martensite ferrite dual phase wear-resisting steel plate and preparation method thereof | |
| CN102337480B (en) | Ultra-high strength steel plate with excellent environmental embrittlement resistance and fatigue resistance, and manufacturing method thereof | |
| CN102220545A (en) | High-carbon and high-strength heat-treated steel rail with high wear resistance and plasticity and manufacturing method thereof | |
| CN100443617C (en) | Pearlite heat-treated steel rail and production method thereof | |
| CN107974636A (en) | A kind of high rigidity high-hardenability pre-hardening plastic die steel and preparation method thereof | |
| CN101353765A (en) | Steel for CT80 grade coiled tubing, and manufacturing method and use thereof | |
| CN106811698A (en) | High-strength steel plate based on fine structure control and manufacturing method thereof | |
| CN100519812C (en) | Production method of pearlite high-strength low-alloy steel rail steel | |
| CN102534403A (en) | Bainite heat-treated steel rail and heat treatment method thereof | |
| CN107779759B (en) | Boron-containing bainite steel rail with excellent delayed fracture resistance and production method thereof | |
| CN108998725A (en) | Track link rail 35MnBM steel and preparation method thereof | |
| CN110129670A (en) | A kind of 1300MPa grades of High-strength high-plasticity drop stamping steel and preparation method thereof | |
| CN103014545B (en) | High-strength steel plate with 900 Mpa-level yield strength and preparation method of steel plate | |
| CN102747290A (en) | Economical wear-resistant steel and manufacturing method thereof | |
| CN109957729A (en) | Wear-resistant steel plate for tramcar turnout and production method thereof | |
| CN105112782A (en) | Low-temperature ferrite LT-FH40 steel plate applied to hot-rolled ships and production method thereof | |
| CN109735765B (en) | Large-sized, ultra-fine grain, high-strength and high-toughness spring steel and production method thereof | |
| CN102367540A (en) | Deep sea pipeline steel produced based on steckel mill and preparation method thereof | |
| CN108048741A (en) | hot rolled bainite steel rail and preparation method thereof | |
| CN115386805A (en) | Low-yield-ratio high-toughness bridge weathering steel and manufacturing method thereof | |
| CN111809114B (en) | Plastic die steel with excellent high-temperature strength and preparation method thereof | |
| CN111254355B (en) | Bainite alloy steel heat and treatment process |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |