CN113699337B - Heat treatment process for 9Cr series heat-resistant steel continuous casting large round billet - Google Patents
Heat treatment process for 9Cr series heat-resistant steel continuous casting large round billet Download PDFInfo
- Publication number
- CN113699337B CN113699337B CN202110899601.0A CN202110899601A CN113699337B CN 113699337 B CN113699337 B CN 113699337B CN 202110899601 A CN202110899601 A CN 202110899601A CN 113699337 B CN113699337 B CN 113699337B
- Authority
- CN
- China
- Prior art keywords
- heat
- round billet
- continuous casting
- resistant steel
- annealing
- 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
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention relates to a 9Cr heat-resistant steel continuous casting round billet heat treatment process, belongs to the technical field of metal material heat treatment, and solves the technical problem that the rejection rate of directly penetrating a large-caliber thick-wall and thin-wall pipe is high due to coarse microstructure and precipitated phase of the 9Cr heat-resistant steel round billet in a one-time long-time annealing process.
Description
Technical Field
The invention belongs to the technical field of heat treatment of metal materials, and particularly relates to a heat treatment process for a 9Cr heat-resistant steel continuous casting round billet.
Background
The 9Cr heat-resistant steel material has the characteristics of high temperature resistance, high pressure resistance and corrosion resistance, and is mainly used for manufacturing key parts of super (super) critical thermal power generating units. The high-quality 9Cr heat-resistant steel continuous casting large round billet can be directly used for penetrating large-caliber thick-wall pipes and thin-wall pipes and is applied to the fields of super (supercritical) thermal power units, petroleum and chemical industry. However, 9Cr heat-resistant steel has a large variety of alloy elements, belongs to sub-peritectic steel, has a complex solidification process, and is easy to generate large thermal stress and coarse structure in the solidification process of large-specification continuous casting billets. The conventional one-time long-time annealing can release partial stress, but has the problems of coarse microstructure and incomplete tissue transformation, so that the mechanical property is influenced, the tube penetrating process is cracked, and the production stability and the product qualification rate are seriously influenced.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, solve the technical problem that the rejection rate of directly penetrating a large-caliber thick-wall and thin-wall pipe is high due to coarse microstructure and precipitated phase of a large round billet of 9Cr heat-resistant steel in one-time long-time annealing process, and provide a heat treatment process of the large round billet of 9Cr heat-resistant steel continuous casting.
The design concept of the invention is as follows:
the 9Cr heat-resistant steel has high alloy content and belongs to the crack sensitive steel category. In the process of continuous casting solidification of a large section, uneven microstructure and stress concentration are easy to form, cracks are caused, and long-time annealing is usually adopted to eliminate the thermal stress of a continuous casting blank of the large section, but the required heat preservation time is long, so that the microstructure, a precipitated phase are easy to be coarse, and residual martensitic structure exists, so that the cracks are easy to be caused in the subsequent pipe penetrating process.
The invention adopts the annealing and tempering process of the large round billet of the 9Cr heat-resistant steel to replace the traditional one-time long-time annealing process. The method not only effectively releases the thermal stress of the large-section continuous casting blank, shortens the high-temperature annealing time of the casting blank and effectively reduces the cost, but also achieves the purposes of refining the microstructure, eliminating the residual martensitic structure and reducing the rejection rate of the subsequent direct pipe penetrating.
In order to solve the problems, the technical scheme of the invention is as follows:
a heat treatment process for a 9Cr heat-resistant steel continuous casting round billet comprises the following steps:
s1, sequentially carrying out electroconverter, LF ladle refining and VD vacuum degassing on raw materials to obtain a steel with the diameter of
Is a 9Cr series heat resistant steel continuous casting large round billet;
s2, annealing process: carrying out red feeding annealing on the 9Cr series heat-resistant steel continuous casting round billet prepared in the step S1, wherein the temperature of the round billet entering an annealing furnace is more than or equal to 500 ℃; then, heating the annealing furnace to 765+/-10 ℃ at a heating speed of less than 100 ℃/h, wherein the heat preservation time is D multiplied by 2.5-2.8 min/mm, and D is the diameter/mm of the continuous casting billet; finally, cooling the large round billet with a furnace to be less than or equal to 500 ℃, discharging, air-cooling to room temperature, and finishing annealing;
s3, tempering: and (3) heating the annealed large round billet in the step (S2) to 650+/-10 ℃ at a heating speed of less than 100 ℃/h, and preserving the temperature D multiplied by 1.2-1.5 min/mm, wherein D is the diameter/mm of the continuous casting billet, then cooling the large round billet with a furnace to less than or equal to 200 ℃, discharging and air cooling to room temperature, and finishing tempering.
Compared with the prior art, the invention has the beneficial effects that:
the invention breaks through the traditional one-time long-time high-temperature annealing (the annealing temperature is 765+/-10 ℃, the annealing heat-preserving time is D multiplied by 3.7-4.3 min/mm, the D is the diameter/mm of the continuous casting billet, and the range is 300-800 mm) of the continuous casting round billet, invents an annealing and tempering process system of the continuous casting round billet, realizes the purpose of low energy consumption of the heat treatment process of the 9Cr heat-resistant steel, can effectively refine the annealing structure and the precipitated phase of the continuous casting round billet of the 9Cr heat-resistant steel, improves the mechanical property of the 9Cr heat-resistant steel, and reduces the rejection rate of the 9Cr heat-resistant steel round billet for directly penetrating thick-wall pipes.
Through on-site actual production data statistics, the rejection rate of the conventional once long-time annealed 9Cr heat-resistant steel round billet directly penetrating through a thick-wall pipe is 6-8%, and the rejection rate of the 9Cr heat-resistant steel round billet directly penetrating through the thick-wall pipe under the annealing and tempering process is 0.45%.
Drawings
FIG. 1 is a diagram of a microstructure after a single long anneal in the prior art;
FIG. 2 is a diagram of the microstructure after annealing and tempering treatment according to the present invention;
FIG. 3 is a microstructure chart of a precipitated phase after a long-time annealing in the prior art;
FIG. 4 is a microstructure of a precipitated phase after annealing and tempering treatment according to the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples.
A heat treatment process for a 9Cr heat-resistant steel continuous casting round billet comprises the following steps:
s1, sequentially refining the raw materials by an 80-ton electric converter, an LF ladle and a VDVacuum degassing to obtain a product with a diameter of
The large round billet is continuously cast by 9Cr heat-resistant steel, and the materials of the large round billet in the implementation are typical steel grades P91 and P92 of 9Cr steel;
TABLE 1P 91 chemical composition control (unit:%)
| Element(s) | C | Si | Mn | P | S | Cr | Mo |
| Content of | 0.08-0.12 | 0.20-0.50 | 0.30-0.60 | ≤0.020 | ≤0.010 | 8.00-9.50 | 0.85-1.05 |
| Element(s) | Nb | V | Al | Ni | Ti | Zr | N |
| Content of | 0.06-0.10 | 0.18-0.25 | ≤0.020 | ≤0.40 | ≤0.010 | ≤0.010 | 0.030-0.070 |
TABLE 2P 92 chemical composition control (unit:%)
S2, annealing process: carrying out red feeding annealing on the 9Cr series heat resistant steel continuous casting round billet prepared in the step S1, wherein the temperature of the round billet in an annealing furnace is 550 ℃; then, heating the annealing furnace to 765 ℃ at a heating speed of 100 ℃/h, and keeping the temperature for 30h; finally, cooling the large round billet to 450 ℃ along with the furnace, discharging, air-cooling to room temperature, and finishing annealing;
s3, tempering: and (3) heating the annealed large round billet in the step (S2) to 650 ℃ at a heating speed of 100 ℃/h, preserving heat for 15h, cooling the large round billet to 200 ℃ along with a furnace, discharging, air-cooling to room temperature, and finishing tempering.
The long-time annealing is usually adopted for eliminating the thermal stress of the large-section continuous casting blank, but the required heat preservation time is long, coarse microstructure and high-temperature ferrite residues are easy to cause, and cracks are easy to cause in the subsequent pipe penetrating process. By adopting the annealing and tempering process of the large round billet of the 9Cr heat-resistant steel, the heat stress of the large-section continuous casting billet is eliminated, the high-temperature annealing time of the casting billet is shortened, the cost is effectively reduced, the microstructure is thinned, and the subsequent pipe penetrating crack generation rate is reduced.
FIGS. 1 and 2 show the microstructure of 9 Cr-series heat resistant steel by conventional single-pass long-time annealing and the "annealing+tempering" process of the present invention, respectively. The microstructure is ferrite + pearlite + part of coarse residual martensite in the primary long-time annealing process, and the microstructure is ferrite + pearlite in the annealing + tempering process, so that the coarse martensite structure is completely eliminated.
From the comparison of fig. 3 and fig. 4, it is evident that the precipitated phase of the 9 Cr-system heat-resistant steel in the "annealing+tempering" process is significantly refined.
The strength and plasticity of the two steels P91 and P92 were compared under different heat treatment systems, and the results are shown in tables 3 and 4, respectively.
TABLE 3 mechanical properties of 9Cr series heat resistant steel P91
| Project | R P0.2 ,MPa | R m ,MPa | A 50 ,％ | Z,％ | Room temperature A KV ,J | HB |
| The invention is annealing and tempering " | 526 | 681 | 28 | 68 | 215 | 210 |
| Conventional primary annealing | 515 | 678 | 28 | 67 | 185 | 210 |
TABLE 4 mechanical properties of 9Cr series heat resistant steel P92
| Project | R P0.2 ,MPa | R m ,MPa | A 50 ,％ | Z,％ | Room temperature A KV ,J |
| The invention is annealing and tempering " | 538 | 705 | 26 | 63 | 207 |
| Conventional primary annealing | 536 | 703 | 25 | 62 | 204 |
As can be seen from tables 3 and 4: the strength and plasticity indexes of the blank prepared by the method are superior to those of the conventional one-time long-time annealing.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (1)
1. A heat treatment process for a 9Cr heat-resistant steel continuous casting round billet is characterized by comprising the following steps:
s1, sequentially carrying out electric converter, LF ladle refining and VD vacuum degassing on raw materials to obtain a 9Cr series heat-resistant steel continuous casting round billet with the diameter of phi 300-phi 800 mm;
s2, annealing process: carrying out red feeding annealing on the 9Cr series heat-resistant steel continuous casting round billet prepared in the step S1, wherein the temperature of the round billet entering an annealing furnace is more than or equal to 500 ℃; then, heating the annealing furnace to 765+/-10 ℃ at a heating speed of less than 100 ℃/h, wherein the heat preservation time is D multiplied by 2.5-2.8 min/mm, and D is the diameter/mm of the continuous casting billet; finally, cooling the large round billet with a furnace to be less than or equal to 500 ℃, discharging, air-cooling to room temperature, and finishing annealing;
s3, tempering: and (3) heating the annealed large round billet in the step (S2) to 650+/-10 ℃ at a heating speed of less than 100 ℃/h, and preserving heat D multiplied by 1.2-1.5 min/mm, wherein D is the diameter/mm of the continuous casting billet, then cooling the large round billet with a furnace to less than or equal to 200 ℃, discharging and air cooling to room temperature, and finishing tempering.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110899601.0A CN113699337B (en) | 2021-08-06 | 2021-08-06 | Heat treatment process for 9Cr series heat-resistant steel continuous casting large round billet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110899601.0A CN113699337B (en) | 2021-08-06 | 2021-08-06 | Heat treatment process for 9Cr series heat-resistant steel continuous casting large round billet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113699337A CN113699337A (en) | 2021-11-26 |
| CN113699337B true CN113699337B (en) | 2023-05-05 |
Family
ID=78652148
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110899601.0A Active CN113699337B (en) | 2021-08-06 | 2021-08-06 | Heat treatment process for 9Cr series heat-resistant steel continuous casting large round billet |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113699337B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115216686A (en) * | 2022-06-10 | 2022-10-21 | 江阴兴澄特种钢铁有限公司 | Manufacturing method of P92 steel continuous casting round billet for extra-large-specification high-temperature service environment |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104532149A (en) * | 2014-12-22 | 2015-04-22 | 江阴兴澄特种钢铁有限公司 | Round steel with high strength and toughness and hydrogen sulfide stress corrosion resistance for drilling tool and manufacturing method of round steel |
| CN110616360A (en) * | 2019-09-28 | 2019-12-27 | 江苏联峰能源装备有限公司 | Production method of 32Cr3Mo1V continuous casting round billet for roll sleeve |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59205449A (en) * | 1983-05-06 | 1984-11-21 | Hitachi Ltd | Heat resistant steel |
| JP3358951B2 (en) * | 1996-09-10 | 2002-12-24 | 三菱重工業株式会社 | High strength, high toughness heat-resistant cast steel |
| CN101538684B (en) * | 2008-09-23 | 2011-06-01 | 山西太钢不锈钢股份有限公司 | Stainless steel tube for brake system of rail vehicle and method for producing same |
| JP5435333B2 (en) * | 2009-04-22 | 2014-03-05 | 新日鐵住金株式会社 | Manufacturing method of α + β type titanium alloy thin plate and manufacturing method of α + β type titanium alloy thin plate coil |
| WO2015088523A1 (en) * | 2013-12-11 | 2015-06-18 | ArcelorMittal Investigación y Desarrollo, S.L. | Cold rolled and annealed steel sheet |
| CN104593697B (en) * | 2015-01-21 | 2016-08-24 | 山西太钢不锈钢股份有限公司 | A kind of manufacture method of power station high-strength temperature-resistant steel plate |
| CN106906340B (en) * | 2017-03-31 | 2018-11-27 | 河南科技大学 | A kind of fine grain heat treatment method |
| CN107245565A (en) * | 2017-06-13 | 2017-10-13 | 中原特钢股份有限公司 | The stress relief annealing method of the effective steel continuous casting round bloom of high-pressure boiler |
| CN108728611B (en) * | 2018-07-30 | 2020-05-26 | 钢铁研究总院 | Grain refinement method for martensite heat-resistant steel large-caliber thick-wall pipe |
-
2021
- 2021-08-06 CN CN202110899601.0A patent/CN113699337B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104532149A (en) * | 2014-12-22 | 2015-04-22 | 江阴兴澄特种钢铁有限公司 | Round steel with high strength and toughness and hydrogen sulfide stress corrosion resistance for drilling tool and manufacturing method of round steel |
| CN110616360A (en) * | 2019-09-28 | 2019-12-27 | 江苏联峰能源装备有限公司 | Production method of 32Cr3Mo1V continuous casting round billet for roll sleeve |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113699337A (en) | 2021-11-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11293072B2 (en) | Process for on-line quenching of seamless steel tube using residual heat and manufacturing method | |
| CN107475620B (en) | Low-temperature pressure container quenching and tempering type A537Cl2 steel plate and its production method | |
| WO2018090682A1 (en) | High hardenability, medium carbon, low alloy round steel for fasteners and manufacturing method therefor | |
| JP7300451B2 (en) | Wire rod for cold heading, processed product using the same, and manufacturing method thereof | |
| CN106011648B (en) | A kind of pinion steel and its production method | |
| WO2022011935A1 (en) | High-strength container thick plate having excellent core toughness, and manufacturing method | |
| CN105506457A (en) | Low-temperature forged steel manufacturing method and product thereof | |
| CN111500832A (en) | Preparation process of alloy steel forge piece | |
| CN106756509B (en) | A kind of high-temperature alloy structural steel and its Technology for Heating Processing | |
| CN103556047A (en) | 450MPa-grade hydrogen-induced-cracking-resistant pressure vessel steel plate and production method thereof | |
| CN111455146A (en) | Strengthening and toughening treatment method for low-alloy martensitic steel and martensitic steel | |
| CN113862434A (en) | Heat treatment process of 35CrNi3MoVR material for thick-wall ultrahigh-pressure container | |
| CN113699337B (en) | Heat treatment process for 9Cr series heat-resistant steel continuous casting large round billet | |
| WO2017050227A1 (en) | Seamless steel tube with high strength and toughness and manufacturing method therefor | |
| CN108913989B (en) | High-performance 10CrMo9-10 steel plate and production method thereof | |
| CN112593059B (en) | Thermal deformation method for reducing delta ferrite content in martensitic stainless steel | |
| CN109628833B (en) | Cr-Mo-Si-V cold-work die steel and preparation method thereof | |
| CN116426846A (en) | Complex-phase precipitated 2.4GPa aluminum-containing high cobalt-nickel secondary hardening steel and preparation method thereof | |
| CN109082513A (en) | A kind of heat treatment process of large size pump case | |
| CN114350969A (en) | Manufacturing method of stainless steel bar for liquid hydrogen storage device | |
| CN113151743A (en) | Manufacturing method and application of conditioning-free cold heading steel wire rod with low martensite content | |
| CN115433872B (en) | Steel with yield strength of 800MPa grade for rare earth engineering machinery and preparation method thereof | |
| CN104148555A (en) | Forge forming method for 1Cr14Mn14Ni stainless steel ring part | |
| WO2022228524A1 (en) | High-strength and heat-resistant casing for heavy oil exploration and manufacturing method therefor | |
| CN115627326B (en) | Method for eliminating delta ferrite in maraging steel |
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 |