CN103740912A - Processing method for improving temper embrittlement resistance of steel plate for pressure vessels - Google Patents
Processing method for improving temper embrittlement resistance of steel plate for pressure vessels Download PDFInfo
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Abstract
The invention provides a processing method for improving the temper embrittlement resistance of a steel plate for pressure vessels, belonging to the technical field of medium plate production. A Cr-Mo system low alloy steel plate for pressure vessels is subjected to weak water cooling treatment after being normalized. The processing method is characterized in that the technical parameters of control are as follows: the rolled steel plate is normalized, the normalizing temperature is 850-950 DEG C, and the steel plate is insulated for 5-30 minutes; the steel plate immediately enters a quenching machine after being discharged to be subjected to weak water cooling treatment, the final cooling temperature of the steel plate is controlled at 300-500 DEG C, and then the steel plate is air-cooled to the room temperature; the weak water cooling speed is controlled at 2-5 DEG C/s; the tempering temperature is 700-760 DEG C, and the tempering and insulating time is 5-30 minutes. The processing method has the advantages that the element P in the treated steel plate can be controlled within 0.015%; the final temper embrittlement resistance of the steel plate can achieve and exceed that of the steel plates produced by traditional methods; a uniform lath bainite structure is formed after the steel plate is normalized and subjected to weak water cooling treatment, thus being beneficial for improvement of the temper embrittlement resistance of the steel plate; as the temper embrittlement resistance of the steel plate is improved by the method of heat treatment, the production cost is lower, the production organization is easier and the method is widely applied.
Description
Technical field
The invention belongs to Heavy Plate Production technical field, particularly relate to a kind of working method that improves the anti-temper embrittlement performance of steel heavy plate for pressure vessels, improved the anti-temper embrittlement of Cr-Mo series low-alloy steel plate for pressurized vessel.
Background technology
Temper embrittlement is some low alloy steel, and particularly Cr-Mo series low-alloy steel long service is in 325～565 ℃ or slow cooling in this temperature range, and when in envrionment temperature, the METAL EMBRITTLEMENT phenomenon of appearance is called temper embrittlement.
Cr-Mo series low-alloy steel specifically comprises GB trade mark 15CrMoR, 14Cr1MoR and 12Cr2Mo1R(American Standard trade mark A387Gr12, A387Gr11, A387Gr22) etc., be Refractory Steel and the anti-hydrogen steel that countries in the world are generally used, be widely used in manufacturing the large-scale plants such as thermal power generating equipment, nuclear power generating equipment and the oil contacting with hydrogen, chemical industry, matchmaker's converting apparatus.Rapidly, scrap build project is many, larger to this type of steel demand in China's oil chemical industry development at present.Because such steel Working environment is in high temperature (300～480 ℃), high pressure (1.5～20MPa), contact with hydrogen, service condition is very severe, therefore requires such steel to have compared with high resistance temper embrittlement performance.
Steel plate temper embrittlement generally just there will be under arms for many years later, be difficult to do experiment and remove direct-detection, therefore generally utilize the cold experiment of step (as shown in Figure 1) to accelerate the steel plate embrittlement tendency in process under arms both at home and abroad, the object that walks cold experiment is to utilize relatively short time (about 230 hours) and economic method to accelerate and simulate the embrittlement of steel plate in long service process to be inclined to.Steel plate walks cold experiment will do minimum simulation postweld heat treatment (Min.PWHT) as last, after walking cold experiment, detect respectively and the cold experiment of matching step front and back steel billet temperature-ballistic work curve, measure ductile-brittle transition temperature (ballistic work 55J corresponding temperature), vTr55 is the cold front spring ductile-brittle transition temperature of step, Δ vTr55 is the cold front difference of the cold rear ductile-brittle transition temperature of step and step, utilizes following formula to judge the anti-temper embrittlement performance of steel plate:
vTr55+2.5ΔvTr55≤10℃
This decision method can effectively be simulated the embrittlement tendency that steel plate is used 30 years under 400～450 ℃ of conditions.
At present, the existing technology that is the anti-temper embrittlement performance of steel plate steel plate about raising Cr-Mo discloses, if French scholar Sylvain Pillot etc. is described in International Journal of Pressure Vessels and Piping110 volume 17-23 page in 2013, mainly by the harmful elements such as P, As, Sn and Sb being controlled to realize on composition, concrete passing through controlled J coefficient and X coefficient, wherein defines J coefficient and is:
J=(Si+Mn) * (P+Sn) * 10
4(chemical element unit is wt%)
Definition X coefficient is:
X=(10P+5Sb+4Sn+As)/100 (chemical element unit is ppm)
Require 15CrMoR, 14Cr1MoR steel plate J≤150,12Cr2Mo1R steel plate J≤100; X coefficient is all less than 15; Additional requirement P+Sn≤0.012% in addition.
Because As, Sn, Sb are general, content is lower, so major control P constituent content, and general requirement is controlled in 0.008%, and steel plate just can obtain good anti-temper embrittlement performance, reaches steel plate and faces hydrogen service requirements.But the strict control on composition, can increase substantially smelting cost and destroy and smelt rhythm, steel plate cost is improved and Steel Plant's organization of production difficulty, therefore urgently seek a kind of relaxing and smelt composition and do not increase smelting difficulty, can significantly promote again the working method of the anti-temper embrittlement performance of Cr-Mo series low-alloy steel steel plate.
Summary of the invention
The object of the present invention is to provide a kind of working method that improves the anti-temper embrittlement performance of steel heavy plate for pressure vessels, overcome now mainly by be strictly controlled to assign to improve Cr-Mo be steel anti-temper embrittlement performance cause production cost high, smelt the shortcoming that difficulty increases.
It is the anti-temper embrittlement performance of steel plate that the present invention mainly processes to improve Cr-Mo by water-cooled a little less than carrying out after steel plate normalizing, the steel plate composition of processing by present method requires to relax to P element, P control of element is 0.015% with interior, and the final anti-temper embrittlement performance of steel plate can reach and be better than the steel plate of produced in conventional processes.
The present invention carries out industrial normalizing thermal treatment after pressurized vessel is smelted with Cr ?Mo series low-alloy steel plate steel plate, carries out weak water-cooled and process after normalizing; The concrete technical parameter of controlling is as follows:
(1) normalizing: roll rear steel plate and carry out normalizing, 850～950 ℃ of normalizing temperatures, insulation 5～30min;
(2) weak water-cooled: coming out of the stove enters immediately quenching press and carry out weak water-cooled and process, and steel plate final cooling temperature is controlled at 300～500 ℃, afterwards again air cooling to room temperature; Weak cooling by water speed control is at 2～5 ℃/s; The weak water-cooled of steel plate normalizing forms even ferrite bainite tissue after processing.
(3) tempering: the weak water-cooled of normalizing is processed rear steel plate and carried out temper, 700～760 ℃ of tempering temperatures, tempering insulation time 5～30min; Steel plate carbide after tempering is separated out along sheaf of bainitic lath and former crystal boundary even dispersion difficult to understand.
After steel plate tempering, carry out successively minimum simulation postweld heat treatment and walk cold experiment the anti-temper embrittlement performance performance of steel plate is assessed; P≤0.015% in the chemical composition of steel plate mentioned above, does not strictly control P on composition.
Steel plate is after minimum simulation postweld heat treatment, and carbide has alligatoring trend, but alligatoring situation not obvious.
The cold rear carbide of steel plate step still has alligatoring trend, but with comparing after minimum simulation postweld heat treatment, the state of carbide and the difference that distributes are little, and this lifting to the anti-temper embrittlement performance of steel plate is very crucial.
By this art breading, steel plate vTr55+2.5 Δ vTr55 value, lower than-60 ℃, far below the decision content of 10 ℃, proves the anti-temper embrittlement excellent performance of steel plate.
The object of carrying out weak water-cooled after steel plate normalizing is to obtain uniform ferrite bainite tissue, as shown in Figure 2; Steel plate carbide after tempering is separated out along sheaf of bainitic lath and former crystal boundary even dispersion difficult to understand, and as shown in Figure 3, the disperse educt of carbide is conducive to the lifting of the anti-temper embrittlement performance of steel plate; After the minimum simulation of steel plate postweld heat treatment, carbide has alligatoring trend, but alligatoring situation not obvious, as shown in Figure 4; The cold rear carbide of steel plate step still has alligatoring trend, and as shown in Figure 5, but with comparing after minimum simulation postweld heat treatment, the state of carbide and the difference that distributes are little, and this lifting to the anti-temper embrittlement performance of steel plate is very crucial.
If in steel plate, lath sheaf of bainitic lath is excessively thick, or inhomogeneous, can cause the inhomogeneous of carbide to be separated out, easily cause Carbide Coarsening, the anti-temper embrittlement performance of steel plate is sharply declined.Therefore very strict for the process parameter control of water-cooled a little less than steel plate.
If final cooling temperature is lower than 300 ℃, the easy flexural deformation of steel plate, affects template and subsequent production; If final cooling temperature is higher than 550 ℃, steel plate inside can not form uniform ferrite bainite, and it is unfavorable that the anti-temper brittleness of steel plate is promoted.
If speed of cooling, higher than 2～5 ℃/s, has martensite at the inner local location of steel plate and generates, martensite is very unfavorable to the anti-temper embrittlement performance of steel plate; If speed of cooling is lower than 2～5 ℃/s, steel plate inside can not form uniform ferrite bainite, unfavorable to the anti-temper embrittlement performance boost of steel plate.
Utilize and accelerate cooling method after normalizing to improve Cr-Mo be that the working method feature of the anti-temper brittleness of steel plate is as follows:
1. on steel plate composition, P is not strictly controlled, general control ,≤0.015%, has reduced smelting difficulty;
2.Cr-Mo series low-alloy steel plate can obtain good anti-temper embrittlement performance by present method;
3. the weak water-cooled of steel plate normalizing forms even ferrite bainite tissue after processing, and after tempering, carbide is at lath bundle and former crystal boundary disperse educt difficult to understand;
4. steel plate is minimum simulates postweld heat treatment and walks after cold experiment, and carbide has alligatoring trend, but distribution difference is little, is conducive to anti-temper brittleness performance boost.
The invention has the advantages that, by heat treated means, significantly promote the anti-temper embrittlement performance of steel plate, on composition, need not especially strictly control P element, P element only requires to be controlled in 0.015% common claimed range, and the anti-temper embrittlement performance of steel plate is more excellent, vTr55+2.5 Δ vTr55 decision content is lower than-60 ℃.With heat-treating methods, promote the anti-temper brittleness performance of steel plate production cost lower, organization of production is easier, and the applicable ability of method is strong.
Accompanying drawing explanation
Fig. 1 is the cold experiment heating curve of step.
Fig. 2 is metallographic structure after steel plate normalizing.
Fig. 3 is metallographic structure after steel plate tempering.
Fig. 4 is metallographic structure after steel plate minimum simulation postweld heat treatment (Min.PWHT).
Fig. 5 is that steel plate walks metallographic structure after cold experiment.
Embodiment
Embodiment 1:
Passing through 14Cr1MoR(A387Gr11CL2) steel plate carries out confirmatory experiment, and steel plate is smelted composition: C:0.13%, Si:0.55, Mn:0.50%, P:0.013%, S:0.001%, Cr:1.25%, Mo:0.46%, As:0.003%, Sb:0.001, Sn:0.0019%, surplus is Fe, J coefficient is 157, X coefficient is that 14.6, J coefficient surpasses 150 decision contents.
Steel plate carries out weak water-cooled after 920 ℃ of insulation 20min, and speed of cooling is controlled at 3 ℃/s, 350 ℃ of final cooling temperatures; At 710 ℃, carry out temper, tempering insulation 15min; After tempering, steel plate samples and at 680 ℃, carries out Min.PWHT processing, soaking time 8 hours; Sample walks cold experiment afterwards, and heating curve as shown in Figure 1.Min.PWHT samples respectively after processing and walk cold experiment, utilizes ballistic work-temperature curve to detect respectively vTr55 and is-115 ℃, and Δ vTr55 is 17 ℃, and vTr55+2.5 Δ vTr55 decision content is-72.5 ℃, the judgement requirement far below 10 ℃.
Embodiment 2:
Passing through 12Cr2Mo1R(A387Gr22CL2) steel plate carries out confirmatory experiment, and steel plate is smelted composition: C:0.11%, Si:0.48, Mn:0.55%, P:0.011%, S:0.002%, Cr:2.24%, Mo:1.00%, As:0.002%, Sb:0.002, Sn:0.002%, surplus is Fe, J coefficient is 134, X coefficient is that 13, J coefficient surpasses decision content 100.
Steel plate carries out weak water-cooled after 920 ℃ of insulation 20min, and speed of cooling is controlled at 4 ℃/s, 330 ℃ of final cooling temperatures; At 730 ℃, carry out temper, tempering insulation 15min; After tempering, steel plate samples and at 680 ℃, carries out Min.PWHT processing, soaking time 8 hours; Sample walks cold experiment afterwards, and heating curve as shown in Figure 1.Min.PWHT samples respectively after processing and walk cold experiment, utilizes ballistic work-temperature curve to detect respectively vTr55 and is-103 ℃, and Δ vTr55 is 8 ℃, and vTr55+2.5 Δ vTr55 decision content is-83 ℃, the judgement requirement far below 10 ℃.
Embodiment 3:
Passing through 15CrMoR(A387Gr12CL2) steel plate carries out confirmatory experiment, and steel plate is smelted composition: C:0.14%, Si:0.44, Mn:0.50%, P:0.014%, S:0.001%, Cr:0.95%, Mo:0.45%, As:0.0015%, Sb:0.003, Sn:0.001%, surplus is Fe, J coefficient is 141, X coefficient is that 16.1, X coefficient surpasses decision content.
Steel plate carries out weak water-cooled after 920 ℃ of insulation 20min, and speed of cooling is controlled at 2 ℃/s, 300 ℃ of final cooling temperatures; At 710 ℃, carry out temper, tempering insulation 15min; After tempering, steel plate samples and at 680 ℃, carries out Min.PWHT processing, soaking time 8 hours; Sample walks cold experiment afterwards, and heating curve as shown in Figure 1.Min.PWHT samples respectively after processing and walk cold experiment, utilizes ballistic work-temperature curve to detect respectively vTr55 and is-106 ℃, and Δ vTr55 is 17 ℃, and vTr55+2.5 Δ vTr55 decision content is-63.5 ℃, the judgement requirement far below 10 ℃.
Claims (3)
1. improve a working method for the anti-temper embrittlement performance of steel heavy plate for pressure vessels, pressurized vessel is processed with carrying out weak water-cooled after the normalizing of Cr-Mo series low-alloy steel plate; It is characterized in that, the concrete technical parameter of controlling is as follows:
(1) normalizing: roll rear steel plate and carry out normalizing, 850～950 ℃ of normalizing temperatures, insulation 5～30min;
(2) weak water-cooled: coming out of the stove enters immediately quenching press and carry out weak water-cooled and process, and steel plate final cooling temperature is controlled at 300～500 ℃, afterwards again air cooling to room temperature; Weak cooling by water speed control is at 2～5 ℃/s;
(3) tempering: 700～760 ℃ of tempering temperatures, tempering insulation time 5～30min.
2. method according to claim 1, is characterized in that, the weak water-cooled of described step (2) steel plate normalizing forms even ferrite bainite tissue after processing.
3. method according to claim 1, is characterized in that, described step (3) light plate carbide after tempering is separated out along sheaf of bainitic lath and former crystal boundary even dispersion difficult to understand.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104805380A (en) * | 2015-05-06 | 2015-07-29 | 山东钢铁股份有限公司 | Low-temper-brittleness Cr-Mo steel plate for high temperature resisting pressure-bearing equipment and preparation method of steel plate |
| CN109837367A (en) * | 2017-11-28 | 2019-06-04 | 中国科学院金属研究所 | Refine the heat treatment process on the island M-A in low-carbon low-alloy steel granular bainite microstructure |
| CN110895274A (en) * | 2018-09-11 | 2020-03-20 | 中国石化工程建设有限公司 | Method for testing temper brittleness of steel and application thereof |
| CN111304414A (en) * | 2020-03-30 | 2020-06-19 | 舞阳钢铁有限责任公司 | Method for reducing tempering embrittlement tendency of 2.25Cr-1Mo steel |
| WO2022179560A1 (en) | 2021-02-25 | 2022-09-01 | 宝山钢铁股份有限公司 | Steel plate for high-temperature equipment and manufacturing method therefor |
| CN115029638A (en) * | 2022-06-24 | 2022-09-09 | 重庆钢铁股份有限公司 | ASTM A387M Gr11CL2 chromium-molybdenum alloy steel plate for pressure container and production method thereof |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104805380A (en) * | 2015-05-06 | 2015-07-29 | 山东钢铁股份有限公司 | Low-temper-brittleness Cr-Mo steel plate for high temperature resisting pressure-bearing equipment and preparation method of steel plate |
| CN109837367A (en) * | 2017-11-28 | 2019-06-04 | 中国科学院金属研究所 | Refine the heat treatment process on the island M-A in low-carbon low-alloy steel granular bainite microstructure |
| CN109837367B (en) * | 2017-11-28 | 2020-09-18 | 中国科学院金属研究所 | Heat treatment process for refining M-A island in granular bainite structure of low-carbon low-alloy steel |
| CN110895274A (en) * | 2018-09-11 | 2020-03-20 | 中国石化工程建设有限公司 | Method for testing temper brittleness of steel and application thereof |
| CN111304414A (en) * | 2020-03-30 | 2020-06-19 | 舞阳钢铁有限责任公司 | Method for reducing tempering embrittlement tendency of 2.25Cr-1Mo steel |
| WO2022179560A1 (en) | 2021-02-25 | 2022-09-01 | 宝山钢铁股份有限公司 | Steel plate for high-temperature equipment and manufacturing method therefor |
| CN115029638A (en) * | 2022-06-24 | 2022-09-09 | 重庆钢铁股份有限公司 | ASTM A387M Gr11CL2 chromium-molybdenum alloy steel plate for pressure container and production method thereof |
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Application publication date: 20140423 |