CN106868275A - The method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel - Google Patents
The method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel Download PDFInfo
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- CN106868275A CN106868275A CN201611230149.4A CN201611230149A CN106868275A CN 106868275 A CN106868275 A CN 106868275A CN 201611230149 A CN201611230149 A CN 201611230149A CN 106868275 A CN106868275 A CN 106868275A
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- 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
- C21D6/00—Heat treatment of ferrous alloys
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- Crystallography & Structural Chemistry (AREA)
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- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The present invention relates to iron and steel smelting technology field, a kind of method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel is specifically provided, it is to set rail steel heating-up temperature in stove to be more than 1250 DEG C, and soaking time is more than 80min.The method provided using the present invention can effectively suppress the precipitation of crystal boundary cementite in eutectoid rail steel, and then improve the hardness and wearability of rail.
Description
Technical field
It is more particularly to a kind of to suppress crystal boundary cementite analysis in hypereutectoid steel rail steel the present invention relates to iron and steel smelting technology field
The method for going out.
Background technology
The intensity of rail can be improved by adding alloying element and heat treatment.For pearlite steel rail, reach
1300MPa has arrived the limit substantially.In order to meet requirement of the heavy haul railway to rail wearability and anti-fatigue performance, hypereutectoid rail
Anti-wear performance can be improved by the density for increasing carburizing body phase in pearlite, and the full face high rigidity of rail head also to improve its tired
Labor performance.Therefore in railway high speed, today of heavy duty, research hypereutectoid rail is significant.
The Fe3C type carbide separated out when cementite is in iron-carbon alloy by the solidification of metastable equilibrium system and cooling transformation,
After austenite is transformed into pearlite, secondary cementite is just distributed on the border of pearlite in continuous net-shaped.Net carbide
Presence be a kind of defect(ive) structure, will increase steel fragility, reduce rail using fatigue, serious can also cause railway thing
Therefore.
The content of the invention
In view of this, the present invention provides a kind of method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel.
The present invention provides a kind of method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel, and it is to set rail steel to exist
Heating-up temperature is more than 1250 DEG C in stove, and soaking time is more than 80min.
Further, in the rail steel C content 0.85~1.05%.
The present invention is by the precipitation and the research of solubility behavior to secondary cementite in eutectoid rail steel, there is provided one kind suppresses
The method that crystal boundary cementite is separated out in hypereutectoid steel rail steel.The cementite on crystal boundary is completely dissolved when rail semifinished product is heated,
I.e. with the rising of austenitizing temperature, the cementite that crystal boundary is separated out is gradually decreased；It is more than when being incubated more than 1250 DEG C
80min, the complete back dissolving of crystal boundary cementite.Crystal boundary carburizing in eutectoid rail steel can effectively be suppressed using the method for originally putting offer
The precipitation of body, and then improve the hardness and wearability of rail.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
The accompanying drawing to be used needed for having technology description is briefly described.
Fig. 1 is 100 times of microstructure pictures after the sample a of the embodiment of the present invention 1 separates out experiment through cementite；
Fig. 2 is 500 times of microstructure pictures after the sample a of the embodiment of the present invention 1 separates out experiment through cementite；
Fig. 3 is 100 times of microstructure pictures after the sample b of the embodiment of the present invention 1 separates out experiment through cementite；
Fig. 4 is 500 times of microstructure pictures after the sample b of the embodiment of the present invention 1 separates out experiment through cementite；
Fig. 5 is the metallurgical microscopic of the sample a1 of the embodiment of the present invention 2；
Fig. 6 is the metallurgical microscopic of the sample a2 of the embodiment of the present invention 2；
Fig. 7 is the metallurgical microscopic of the sample a4 of the embodiment of the present invention 2；
Fig. 8 is the metallurgical microscopic of the sample a5 of the embodiment of the present invention 2.
Specific embodiment
The invention discloses a kind of method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel, those skilled in the art
Present disclosure can be used for reference, technological parameter realization is suitably modified.In particular, all similar replacements and change are right
It is it will be apparent that they are considered as being included in the present invention for those skilled in the art.The method of the present invention and application are
It is described through by preferred embodiment, related personnel can be not substantially being departed from present invention, spirit and scope to this
Methods and applications described in text are modified or suitably change is realized and apply the technology of the present invention with combining.
C content in hypereutectoid rail must make the carburizing on crystal boundary when rail base is heated about 0.86~1.1%
Body is completely dissolved, and suppresses it in cooling procedure after rolling and separated out in crystal boundary, promotes transgranular precipitation, improves cementite institute accounting
Example improves hardness, the wearability of rail.
The present invention provides a kind of method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel, and it is specially：Steel is set
Rail steel heating-up temperature in stove is more than 1250 DEG C, and soaking time is more than 80min.
Further, in the rail steel C content 0.85~1.05%.
The present invention is by the precipitation and the research of solubility behavior to secondary cementite in eutectoid rail steel, there is provided one kind suppresses
The method that crystal boundary cementite is separated out in hypereutectoid steel rail steel.The cementite on crystal boundary is completely dissolved when rail semifinished product is heated,
I.e. with the rising of austenitizing temperature, the cementite that crystal boundary is separated out is gradually decreased；It is more than when being incubated more than 1250 DEG C
80min, the complete back dissolving of crystal boundary cementite.Crystal boundary oozes during the method provided using the present invention can effectively suppress eutectoid rail steel
The precipitation of carbon body, and then improve the hardness and wearability of rail.
With reference to embodiment, the present invention is expanded on further：
Embodiment 1- crystal boundaries cementite separates out experiment
Two kinds of experiment steel are heated into 4h at 1200 DEG C, then the cold 22h of stove.This step is to make cementite in crystal boundary by slow cooling
Separate out completely, two used in the present embodiment kind sample steel is respectively labeled as sample a and sample b, carbon containing to be followed successively by 1.02wt%
And 0.86wt%.Through cementite separate out experiment after microstructure picture as shown in Figures 1 to 4.
From Fig. 1 to Fig. 4, the C content of sample a experiment steel is higher, and by slow cooling, secondary cementite is in netted along crystal boundary
Separate out.Sample b experiment steel part crystal boundary has secondary cementite to separate out.
Embodiment 2- heat treatment experiments
Simulate the heat treatment experiment of heating steel billet, in order to retain the reset condition of crystal boundary, direct oil quenching after heat treatment.Specifically
, because sample a tests steel by slow cooling, secondary cementite is more apparent in netted intercrystalline precipitation, the sample a realities stove after cold
Test steel curved beam and be cut into 5 pieces, be respectively labeled as sample a1~a5, tested by the technique of table 1.Under research various austenitizing,
Crystal boundary separates out the back dissolving situation of cementite, and photo is as shown in Fig. 5 to Fig. 8.
The handling process parameter of table 1
| Numbering | Technology for Heating Processing |
| a1 | 1250 DEG C × 50min, oil cooling |
| a2 | 1250 DEG C × 80min, oil cooling |
| a3 | 1200 DEG C × 50min, oil cooling |
| a4 | 1150 DEG C × 50min, oil cooling |
| a5 | 1100 DEG C × 50min, oil cooling |
Drawn by experimental result：
With the rising of austenitizing temperature, the cementite that crystal boundary is separated out is gradually decreased.When the insulation at 1250 DEG C
80min, the complete back dissolving of crystal boundary cementite.
The heating-up temperature of continuous casting billet, soaking time provide theoretical foundation, i.e. rail steel during for hypereutectoid rail Industry trial-production
Heating-up temperature have to be larger than 1250 DEG C in stove, and soaking time is more than 80min.
The above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, under the premise without departing from the principles of the invention, some improvements and modifications can also be made, these improvements and modifications also should
It is considered as protection scope of the present invention.
Claims (2)
1. a kind of method that crystal boundary cementite is separated out in suppression hypereutectoid steel rail steel, it is characterised in that setting rail steel is in stove
Heating-up temperature is more than 1250 DEG C, and soaking time is more than 80min.
2. the method that crystal boundary cementite is separated out in suppression hypereutectoid steel rail steel according to claim 1, it is characterised in that institute
C content is 0.85~1.05% in stating rail steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611230149.4A CN106868275A (en) | 2016-12-28 | 2016-12-28 | The method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611230149.4A CN106868275A (en) | 2016-12-28 | 2016-12-28 | The method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel |
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| CN201611230149.4A Pending CN106868275A (en) | 2016-12-28 | 2016-12-28 | The method for suppressing crystal boundary cementite precipitation in hypereutectoid steel rail steel |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101921950A (en) * | 2010-09-02 | 2010-12-22 | 攀钢集团有限公司 | Steel rail used for high-speed and quasi-high speed railways and manufacturing method thereof |
| CN102220545A (en) * | 2010-04-16 | 2011-10-19 | 攀钢集团有限公司 | High-carbon and high-strength heat-treated steel rail with high wear resistance and plasticity and manufacturing method thereof |
| CN105154773A (en) * | 2015-07-23 | 2015-12-16 | 攀钢集团攀枝花钢铁研究院有限公司 | Steel rail for heavy haul railway and production method and application of steel rail for heavy haul railway |
-
2016
- 2016-12-28 CN CN201611230149.4A patent/CN106868275A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102220545A (en) * | 2010-04-16 | 2011-10-19 | 攀钢集团有限公司 | High-carbon and high-strength heat-treated steel rail with high wear resistance and plasticity and manufacturing method thereof |
| CN101921950A (en) * | 2010-09-02 | 2010-12-22 | 攀钢集团有限公司 | Steel rail used for high-speed and quasi-high speed railways and manufacturing method thereof |
| CN105154773A (en) * | 2015-07-23 | 2015-12-16 | 攀钢集团攀枝花钢铁研究院有限公司 | Steel rail for heavy haul railway and production method and application of steel rail for heavy haul railway |
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Application publication date: 20170620 |
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