CN101509058A - High-chromium ferrite heat-resistant steel fine-deformation martensite lath microstructure refinement method - Google Patents
High-chromium ferrite heat-resistant steel fine-deformation martensite lath microstructure refinement method Download PDFInfo
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- CN101509058A CN101509058A CNA2009100681685A CN200910068168A CN101509058A CN 101509058 A CN101509058 A CN 101509058A CN A2009100681685 A CNA2009100681685 A CN A2009100681685A CN 200910068168 A CN200910068168 A CN 200910068168A CN 101509058 A CN101509058 A CN 101509058A
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Abstract
The invention relates to a method for refining the micro-deformation martensitic lath microstructure of high-chromium (Cr) ferrite heat-resistant steel, comprising the following steps: the high-chromium (Cr) ferrite heat-resistant steel is hot-rolled into tubes or plates, and is generally produced into samples with the wall thickness being not larger than 6cm to be ensured to reach required heating and cooling rate; the method is characterized in that the samples are placed in a high-frequency induction heat-treating device for treatment, wherein, the procedures are set as follows: setting the heating rate as 30 to 80 K/min; preserving temperatrue for 5 to 15min after the temperature rises from room temperature to 1,223 to 1,323 K; further cooling to 1,023 to 1,073 K at a cooling rate equal to the heating rate; carrying out slight compressive stress deformation, loading for 3 to 10 s and then unloading immediately, wherein, the stress loaded is 10 to 40 MPa; and then, cooling to the room temperature at the rate equal to the cooling rate. Compared with the conventional method for refining the martensitic lath microstructure, which is characterized in that the deformation is formed by increasing the stress, the method of the invention for refining alloy grains has the advantages of small loaded stress and short loading time; the energy consumption is much lower than that of the conventional method; furthermore, the high-temperature performance of the alloy is much improved, therefore, the method is a potential and practical manufacturing method.
Description
Technical field
The invention belongs to high chromium content ferrite high temperature steel production technical field, the little distortion martensite lath of particularly a kind of high chromium content ferrite high temperature steel structure refinement method.
Background technology
The progress of the development of high temperature steel and the energy, power and mechanical industry is closely related.In fields such as thermal power generation, nuclear energy, aerospace, aviation, oil and chemical industry, the quality of high temperature steel performance is the key of success or not.For solving energy shortage and the problem of environmental pollution that becomes increasingly conspicuous, the high-level efficiency generating has become hot issue in recent years.For improving thermo-efficiency, super (surpassing) critical parameter of countries in the world thermal power generation unit parameter forward develop, and improving thermo-efficiency mainly is the heat power problem, and thermo-efficiency mainly improves by improving the working steam temperature in power plant.Just setting about parameter as Japan, the U.S. etc. is that 34.5Mpa, 620～650 ℃ unit are comprehensively studied, and makes every effort to make thermo-efficiency to improve more than 10%, and the unit that generates electricity like this discharges CO every year less
2Be equivalent to the coal for power generation more than 26 tons.This shows that the development of high temperature steel has considerable meaning to the realization of the energy-saving and emission-reduction major action that China is implementing.
The raising of vapor temperature has proposed requirements at the higher level to the use properties of boiler steel.High temperature steel in the boi1er tube is in the medium-term and long-term work of high temperature, high pressure and steam corrosion, and the tissue of steel and performance will change, and the metallic high temperature performance is obviously worsened, thereby influences the security of equipment operation.Everything requires boi1er tube to have following good Performance Match with high temperature steel: 1. high tensile strength and yield strength, good impelling strength; 2. You Yi high temperature endurance performance, creep-resistant property, the good high-temperature structure stability; 3. the anti-oxidant and anti-steam corrosion performance of good high-temperature; 4. good cold and hot working performance, welding property and bending property; 5. low thermal coefficient of expansion and thermal conductive resin; 6. good economic.
Be further to improve the steam use temperature of high temperature steel, in the hope of improving the boi1er tube heat exchanger effectiveness, each state is all carrying out the research and development that are suitable for the heat resistance steel that use under elevated steam conditions energetically at present.Developed countries such as the U.S., Europe and Japan take the lead one after another and research and develop authentication, set up the high temperature steel system of super (surpassing) critical generating set on the one hand, improve existing high temperature steel system on the other hand and also develop more advanced high temperature steel.
Boiler steel divides ferrite and austenitic heat-resistance steel two classes both at home and abroad.Compare with austenitic steel, jessop has become the first-selected steel grade of boiler tube steel because of its excellent comprehensive performance.The development of ferritic steel can be divided into two main lines: the one, vertically by improving the content (from 2.25Cr to 12Cr) of main heat-resisting element Cr gradually; The 2nd, laterally by adding V, Nb, Mo, W and Co etc.Begin the jessop to 9～12%Cr from simple C-Mn steel, by adopting alloying and organizational controls, corresponding high temperature creep strength has improved nearly 10 times, and wherein 9～12%Cr high chromium content ferrite is heat-resisting is that steel is the highest.Therefore, developed country will research and develop emphasis to have turned to 9～12%Cr be high chromium content ferrite high temperature steel.
For improving the use temperature and the permissible stress of jessop, need badly systematic study is carried out in formation of high chromium content ferrite high temperature steel tissue and forming technology, explore new efficient hardening approach.From tissue, after the prior heat treatment, high chromium content ferrite high temperature steel tissue is formed (seeing Fig. 1 a and Fig. 1 b) by the martensite lath and the carbonitride of separating out, and wherein original austenite grain is divided into several born of the same parents by approximately parallel martensite Shu Zucheng, and throw out is mainly by the M of corynebacterium
23C
6The granular MX type carbonitride that type carbide and disperse are distributed in the lath is formed.Having given 9～12%Cr just because of the refined crystalline strengthening of this martensite lath with the precipitation strength of the carbonitride of separating out is high chromium content ferrite high temperature steel mechanical property preferably.Therefore, do not changing under the situation about being grouped into, seeking the method for refinement high chromium content ferrite high temperature steel martensite lath tissue effectively from the forming technology process, thereby further improve its high-temperature behavior, having very important and practical meanings.
Summary of the invention
Purpose of the present invention is exactly that to adopt the method for the little distortion in high-temperature zone to come refinement 9～12%Cr be the martensite lath tissue of high chromium content ferrite high temperature steel, thus the over-all properties of raising high temperature steel, and then advance its application in practice.
The little distortion martensite lath of high chromium content ferrite high temperature steel of the present invention structure refinement method, technical scheme is as follows:
Is tubing or sheet material with high chromium content ferrite high temperature steel through hot rolling, for guaranteeing to meet the requirements of heating and cooling speed, generally makes the sample that wall thickness is not more than 6 centimetres; It is characterized in that sample is put into the high-frequency induction thermal treatment unit to be handled: setting program is: temperature rise rate is 30～80K/min, after rising to 1223～1323K from room temperature, be incubated 5～15 minutes, reduce to 1023～1073K with identical rate of cooling again, carry out microdeformation then, the stress intensity that pressurizes is 10～40Mpa, and unloading is immediately reduced to room temperature with identical speed then behind loading 3～10s.
Experiment is that the chemical ingredients scope of high chromium content ferrite high temperature steel sees Table 1 with 9～12%Cr.Raw materials used purity all is higher than 99%, by melting and carry out vacuum refinement and two technological processs of external refining in electric arc furnace or induction furnace after the set composition proportion, be tubing or sheet material (wall thickness generally should be not more than 6 centimetres, to guarantee that after the normalizing be the lath martensite tissue) through hot rolling then.
The chemical ingredients scope of table 1 high chromium content ferrite high temperature steel
| Constituent element | Content (wt.%) |
| C | 0.01-0.09 |
| Si | 0.02-0.04 |
| Cr | 8.5-12.0 |
| Mo | 0.3-1.3 |
| Mn | 0.3-0.5 |
| V | 0.1-0.3 |
| Nb | 0.05-0.08 |
| N | 0.01-0.05 |
| Ti | <0.01 |
| Al | <0.04 |
| W | <2.5 |
| B | <0.05 |
The method of the refinement high chromium content ferrite high temperature steel martensite lath tissue that the present invention adopts is different from the martensite lath thinning microstructure method of traditional increasing stress machining deformation.The loading stress that adopts is little, loading time is short, used energy loss-rate traditional method significantly reduces, and the performance of high chromium content ferrite high temperature steel has greatly improved, and is a kind of very potential practical production method (as realizing by the finishing process in the production of high chromium content ferrite heat resisting pipe).Can see from the contrast metallograph of Fig. 2 and Fig. 3, with do not carry out little deformation process sample (see figure 2) and compare, adopt the high chromium content ferrite high temperature steel sample (see figure 3) martensite lath structure refinement significantly (wherein martensite lath average headway 15.0 microns before little distortion are refined as after the little distortion of 1048K 4.1 microns) after the inventive method is handled, at selected temperature (1023K, 1030K, 1048K, 1058K and 1073K) carry out behind the 20Mpa minimal-stress deformation that average martensite lath spacing all has obvious refinement in the high chromium content ferrite high temperature steel sample tissue, that wherein refinement amplitude is less is 1073K, pairing average martensite lath spacing is 9.3 microns, and thinning effect is 1048K (4.1 microns) the most significantly.Concerning congruent high chromium content ferrite high temperature steel, adopt its corresponding high-temperature behavior of little distortion refinement martensite lath tissue back obviously to improve.Fig. 5 has provided at 1023K, 1030K, 1048K, 1058K and 1073K and has carried out the pairing 200 ℃ of yield strength sizes of minimal-stress deformation (20Mpa) back high chromium content ferrite high temperature steel.Compare (corresponding yield strength is 512Mpa) with not adopting little distortion refinement martensite lath tissue sample, the high chromium content ferrite high temperature steel martensite lath after little deformation process is organized tiny more, and its corresponding yield strength is high more.The yield strength the highest (620Mpa) of the little distortion high chromium content ferrite of 1048K high temperature steel, the yield strength of the little distortion high chromium content ferrite of 1073K high temperature steel also has raising (535Mpa) by a relatively large margin, and this shows this method versatility and importance in process of production.
Description of drawings
Fig. 1 a: high chromium content ferrite high temperature steel typical case martensite lath is organized synoptic diagram;
Fig. 1 b: high chromium content ferrite high temperature steel typical case carbonitride distribution schematic diagram;
Fig. 2: high chromium content ferrite high temperature steel typical gold phase constitution before little deformation process;
Fig. 3: high chromium content ferrite high temperature steel typical gold phase constitution after little deformation process;
Fig. 4: the little distortion high chromium content ferrite of differing temps high temperature steel martensite lath average headway size;
Fig. 5: 200 ℃ of yield strength sizes of the little distortion high chromium content ferrite of differing temps high temperature steel.
Embodiment
Concrete technical scheme embodiment of the present invention is as follows:
Embodiment 1: corresponding high chromium content ferrite high temperature steel
Experiment sees Table 1 with the chemical ingredients scope of high chromium content ferrite high temperature steel.Raw materials used purity all is higher than 99%, by melting and carry out vacuum refinement and two technological processs of external refining in electric arc furnace or induction furnace after the set composition proportion, is tubing or sheet material through hot rolling then.
Get the sample that melts the identical component after joining, cut cylindrical sample with the line cutting from steel pipe, the polar expansion specimen size is diameter 5mm, long 10mm; Putting into the high-frequency induction thermal treatment unit behind the cleaning-drying handles: setting program is: temperature rise rate is 30～80K/min, after rising to 1223～1323K from room temperature, be incubated 5～15 minutes, reduce to 1023～1073K with identical rate of cooling again, carry out minimal-stress deformation then, it is 10～40Mpa that institute adds stress intensity, and unloading is immediately reduced to room temperature with identical speed then behind loading 3～10s.
Embodiment 2: corresponding T91 high chromium content ferrite high temperature steel
(1) specimen preparation
Raw materials used purity all is higher than 99%, by the melting and carry out vacuum refinement and two technological processs of external refining in electric arc furnace or induction furnace of the set composition proportion of table 2 (corresponding T91 high chromium content ferrite high temperature steel) back, be tubing or sheet material (1.5 centimetres of wall thickness) through hot rolling then.
The chemical ingredients scope of table 2 T91 high chromium content ferrite high temperature steel
| Constituent element | Content (wt.%) |
| C | 0.09 |
| Si | 0.03 |
| Cr | 9.1 |
| Mo | 1.1 |
| Mn | 0.4 |
| V | 0.2 |
| Nb | 0.07 |
| N | 0.04 |
| Al | 0.01 |
(2) little deformation process
Sample is put into the high-frequency induction thermal treatment unit to be handled: setting program is: temperature rise rate is 50K/min, after rising to 1273K from room temperature, be incubated 5 minutes, reduce to 1030K with identical rate of cooling again, carry out minimal-stress deformation then, it is 30Mpa that institute adds stress intensity, and unloading is immediately reduced to room temperature with identical speed then behind the loading 10s.
After above-mentioned little deformation process, the average martensite lath spacing in this T91 high chromium content ferrite high temperature steel sample tissue is refined as 6.2 microns from 15.0 microns, and pairing 200 ℃ of yield strengths are brought up to 562Mpa from 512Mpa.
Embodiment 3: corresponding T92 high chromium content ferrite high temperature steel
(1) specimen preparation
Raw materials used purity all is higher than 99%, by the melting and carry out vacuum refinement and two technological processs of external refining in electric arc furnace or induction furnace of the set composition proportion of table 3 (corresponding T92 high chromium content ferrite high temperature steel) back, be tubing or sheet material (1.5 centimetres of wall thickness) through hot rolling then.
The chemical ingredients scope of table 3 T92 high chromium content ferrite high temperature steel
| Constituent element | Content (wt.%) |
| C | 0.08 |
| Si | 0.03 |
| Cr | 9.1 |
| Mo | 0.4 |
| Mn | 0.4 |
| V | 0.2 |
| Nb | 0.05 |
| N | 0.04 |
| Al | 0.01 |
| W | 1.0 |
| B | 0.05 |
(2) little deformation process
Sample is put into the high-frequency induction thermal treatment unit to be handled: setting program is: temperature rise rate is 50K/min, after rising to 1273K from room temperature, be incubated 5 minutes, reduce to 1073K with identical rate of cooling again, carry out minimal-stress deformation then, it is 30Mpa that institute adds stress intensity, and unloading is immediately reduced to room temperature with identical speed then behind the loading 10s.
After above-mentioned little deformation process, the average martensite lath spacing in this T92 high chromium content ferrite high temperature steel sample tissue is refined as 7.2 microns from 15.3 microns, and pairing 200 ℃ of yield strengths are brought up to 569Mpa from 518Mpa.
Embodiment 4: corresponding T92 jessop
(1) specimen preparation
Raw materials used purity all is higher than 99%, by the melting and carry out vacuum refinement and two technological processs of external refining in electric arc furnace or induction furnace of the set composition proportion of table 3 (corresponding T92 jessop) back, be tubing or sheet material (1.5 centimetres of wall thickness) through hot rolling then.
(2) little deformation process
Sample is put into the high-frequency induction thermal treatment unit to be handled: setting program is: temperature rise rate is 70K/min, after rising to 1273K from room temperature, be incubated 10 minutes, reduce to 1048K with identical rate of cooling again, carry out minimal-stress deformation then, it is 35Mpa that institute adds stress intensity, and unloading is immediately reduced to room temperature with identical speed then behind the loading 8s.
After above-mentioned little deformation process, the average martensite lath spacing in this T92 high chromium content ferrite high temperature steel sample tissue is refined as 5.6 microns from 15.3 microns, and pairing 200 ℃ of yield strengths are brought up to 587Mpa from 518Mpa.
The little distortion martensite lath of the high chromium content ferrite high temperature steel structure refinement method that the present invention proposes, be described by embodiment, person skilled obviously can be changed or suitably change and combination making method as herein described in not breaking away from content of the present invention, spirit and scope, realizes technology of the present invention.Special needs to be pointed out is, the replacement that all are similar and change apparent to those skilled in the artly, they are regarded as being included in spirit of the present invention, scope and the content.
Claims (1)
1. the little distortion martensite lath of a high chromium content ferrite high temperature steel structure refinement method is tubing or sheet material with high chromium content ferrite high temperature steel through hot rolling, for guaranteeing to meet the requirements of heating and cooling speed, generally makes the sample that wall thickness is not more than 6 centimetres; It is characterized in that sample is put into the high-frequency induction thermal treatment unit to be handled: setting program is: temperature rise rate is 30～80K/min, after rising to 1223～1323K from room temperature, be incubated 5～15 minutes, reduce to 1023～1073K with identical rate of cooling again, carry out microdeformation then, the stress intensity that pressurizes is 10～40Mpa, and unloading is immediately reduced to room temperature with identical speed then behind loading 3～10s.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103014514A (en) * | 2012-11-27 | 2013-04-03 | 天津大学 | Novel high-chromium ferritic heat-resistant steel and martensite lath refining method |
| CN103290188A (en) * | 2013-05-30 | 2013-09-11 | 天津大学 | Method for controlling martensite/austenite structure in process of straightening WB36 steel pipes |
| CN103305663A (en) * | 2013-05-30 | 2013-09-18 | 天津大学 | Martensite lath tissue refining method under effect of strong magnetic field of heat-resistant steel of 9-12% Cr system |
| CN103966408A (en) * | 2013-01-30 | 2014-08-06 | 中国科学院金属研究所 | Technology for preparing multi-scale nitride-reinforced martensite heat-resistant steel |
| CN106086347A (en) * | 2016-08-30 | 2016-11-09 | 华北理工大学 | A kind of method promoting large-size workpiece crystal grain to refine |
| CN106399655A (en) * | 2016-09-20 | 2017-02-15 | 天津理工大学 | Method for refining ferritic structure by loading microstress on 20MnSi thread steel |
| CN108728621A (en) * | 2017-04-14 | 2018-11-02 | 天津大学 | A kind of martensite lath thinning method of high martensitic chromium steel |
-
2009
- 2009-03-18 CN CNA2009100681685A patent/CN101509058A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103014514A (en) * | 2012-11-27 | 2013-04-03 | 天津大学 | Novel high-chromium ferritic heat-resistant steel and martensite lath refining method |
| CN103966408A (en) * | 2013-01-30 | 2014-08-06 | 中国科学院金属研究所 | Technology for preparing multi-scale nitride-reinforced martensite heat-resistant steel |
| CN103966408B (en) * | 2013-01-30 | 2016-03-16 | 中国科学院金属研究所 | A kind of technique obtaining multiple dimensioned nitride strengthening martensite heat-resistant steel |
| CN103290188A (en) * | 2013-05-30 | 2013-09-11 | 天津大学 | Method for controlling martensite/austenite structure in process of straightening WB36 steel pipes |
| CN103305663A (en) * | 2013-05-30 | 2013-09-18 | 天津大学 | Martensite lath tissue refining method under effect of strong magnetic field of heat-resistant steel of 9-12% Cr system |
| CN103290188B (en) * | 2013-05-30 | 2014-10-15 | 天津大学 | Method for controlling martensite/austenite structure in process of straightening WB36 steel pipes |
| CN106086347A (en) * | 2016-08-30 | 2016-11-09 | 华北理工大学 | A kind of method promoting large-size workpiece crystal grain to refine |
| CN106399655A (en) * | 2016-09-20 | 2017-02-15 | 天津理工大学 | Method for refining ferritic structure by loading microstress on 20MnSi thread steel |
| CN108728621A (en) * | 2017-04-14 | 2018-11-02 | 天津大学 | A kind of martensite lath thinning method of high martensitic chromium steel |
| CN108728621B (en) * | 2017-04-14 | 2020-05-05 | 天津大学 | Method for refining martensite lath of high-chromium martensite steel |
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