CN117448682A - Ultra-fine grain Cr-Ni-Mo alloy steel forging material and manufacturing method thereof - Google Patents

Ultra-fine grain Cr-Ni-Mo alloy steel forging material and manufacturing method thereof Download PDF

Info

Publication number
CN117448682A
CN117448682A CN202311429698.4A CN202311429698A CN117448682A CN 117448682 A CN117448682 A CN 117448682A CN 202311429698 A CN202311429698 A CN 202311429698A CN 117448682 A CN117448682 A CN 117448682A
Authority
CN
China
Prior art keywords
percent
forging
alloy steel
steel
temperature
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.)
Pending
Application number
CN202311429698.4A
Other languages
Chinese (zh)
Inventor
郑凯哲
徐国庆
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiangsu Zhuhong Forging Co ltd
Original Assignee
Jiangsu Zhuhong Forging Co ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Jiangsu Zhuhong Forging Co ltd filed Critical Jiangsu Zhuhong Forging Co ltd
Priority to CN202311429698.4A priority Critical patent/CN117448682A/en
Publication of CN117448682A publication Critical patent/CN117448682A/en
Pending legal-status Critical Current

Links

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
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
    • B21J5/002—Hybrid process, e.g. forging following casting
    • 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
    • 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
    • C21D1/28—Normalising
    • 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
    • C21D11/00—Process control or regulation for heat treatments
    • 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
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • 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
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • 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
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Forging (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

The invention discloses an ultrafine grain Cr-Ni-Mo alloy steel forging material and a manufacturing method thereof, and relates to the technical field of alloy steel forging materials, wherein the alloy steel forging material comprises the following chemical components in percentage by mass: 0.38 to 0.43 percent of C, 0.25 to 0.35 percent of Si, 0.70 to 0.80 percent of Mn, less than or equal to 0.015 percent of S, less than or equal to 0.015 percent of P, 0.80 to 0.85 percent of Cr, 0.30 to 0.35 percent of Mo, 1.70 to 1.95 percent of Ni, 0.020 to 0.050 percent of Al, 90 to 150ppm of N, 0.06 to 0.15 percent of V, and the balance of iron and other unavoidable impurities. The alloy steel forging material has the grain size of more than or equal to 7 grades, has good toughness matching and organization, and can pass ultrasonic flaw detection inspection with phi of 2.5 mm; the manufacturing method is simple and convenient, has low dependency on equipment, high preparation efficiency and low energy consumption, and is suitable for continuous large-scale production.

Description

Ultra-fine grain Cr-Ni-Mo alloy steel forging material and manufacturing method thereof
Technical Field
The invention relates to the technical field of alloy steel forging materials, in particular to an ultrafine grain Cr-Ni-Mo alloy steel forging material and a manufacturing method thereof.
Background
The large forging is a bearing and transmission structural component in power station equipment such as nuclear power, thermal power and the like and large metallurgical, mining and transportation equipment, belongs to a core component, and is a foundation for reliable operation of the equipment. The large-scale of equipment also makes the forging bigger, especially under the design concept guidance of improvement efficiency, reduction consumption, safe and reliable, besides the high alloy steel is used in a large number, the combination parts which are formed by the subsequent assembly originally are integrated into a whole, so that the size and the weight of the single forging are increased sharply. With the gradual increase of the weight of large forgings, the problem of coarse grain of alloy steel forgings is more and more prominent. The coarse grain not only prevents flaw detection, but also strongly reduces toughness and plasticity of the forging. In the face of the increasingly higher quality requirements of forgings, the problem of coarse grain has come to be solved.
In order to solve the problems of coarse and uneven grains caused by the inheritance of the structure of the alloy steel forging material, the traditional method generally adopts a heat treatment process after forging with multiple normalizing, however, the traditional multiple normalizing process needs to be subjected to multiple heating and cooling, the energy waste is large, the process is complex, the working procedure time is long, the operation control difficulty is high, the actual effect is unstable, the comprehensive manufacturing cost is high, and the comprehensive manufacturing cost has a large space and can be improved. The main scheme for solving the problem of coarse grain at present is as follows: (1) Controlling the pouring temperature in the smelting or casting process to avoid overgrowth of crystal grains; (2) The method can avoid that grains which grow too fast in the heating process can not be refined by recrystallization due to the fact that the heating temperature of the forging is too high and the forging ratio is insufficient. However, the prior alloy steel forging material does not thoroughly solve the problem of coarse grain due to unreasonable selection of the component formula and the manufacturing process parameters, and causes larger energy waste.
For example, the chinese patent of application No. 201110009744.6 discloses a grain refinement method for a large-sized forging of medium-high alloy steel in the technical field of metal heat treatment, in which the forged forging is cooled to the temperature of the nose tip of a pearlite transformation zone after austenitizing to perform isothermal heat preservation or fluctuation heat preservation, isothermal decomposition of pearlite is realized, then the forging is cooled to room temperature and subjected to a secondary austenitizing process, and then re-crystallization is realized to refine grains again. The invention solves the problems of unstable grain refining effect, coarse grain and serious mixed grain phenomena of the large forging by the traditional multiple normalizing process in actual production. The structure inheritance is cut off and eliminated through incomplete isothermal equilibrium decomposition of austenite, the prior austenite average grain size of more than grade 5 of ASTM No. is obtained, the structure state of the large forging is improved, the ultrasonic flaw detection performance of the large forging is improved, the working hour is greatly shortened, the energy consumption is reduced, and the cost is saved. However, the grains thereof are further refined, and the grain refinement is not controlled from the angles of alloy steel formulation, casting temperature, heating temperature, forging ratio.
Therefore, the development of the superfine grain Cr-Ni-Mo alloy steel forging material and the manufacturing method thereof meet the market demand, have wide market value and application prospect, and have very important significance for promoting the development of grain refinement control technology.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide an ultrafine grain Cr-Ni-Mo alloy steel forging material with grain size more than or equal to 7 grade, good toughness matching and organization and capable of passing ultrasonic flaw detection with phi of 2.5mm and a manufacturing method thereof.
In order to achieve the above purpose, the invention adopts the following technical scheme: the ultra-fine grain Cr-Ni-Mo alloy steel forging material is characterized by comprising the following chemical components in percentage by mass: 0.38 to 0.43 percent of C, 0.25 to 0.35 percent of Si, 0.70 to 0.80 percent of Mn, less than or equal to 0.015 percent of S, less than or equal to 0.015 percent of P, 0.80 to 0.85 percent of Cr, 0.30 to 0.35 percent of Mo, 1.70 to 1.95 percent of Ni, 0.020 to 0.050 percent of Al, 90 to 150ppm of N, 0.06 to 0.15 percent of V, and the balance of iron and other unavoidable impurities.
Another object of the present invention is to provide a method for manufacturing the ultra-fine grain Cr-Ni-Mo alloy steel forging, comprising the steps of:
firstly, adding ingredients according to weight percentage into a smelting furnace, and smelting furnace burden into primary molten steel;
step two, refining outside the furnace: refining the molten steel obtained in the step one into alloy steel through LF and VD or RH vacuum refining treatment, and casting the molten steel into steel ingots by adopting a mold injection process after refining;
step three, forging: forging the alloy steel ingot obtained in the second step, and rolling the obtained ingot after heating to obtain a finished product size;
step four, heat treatment: and (3) placing the forge piece after natural cooling in the step (III) into an annealing furnace for heat treatment.
Preferably, in the first step, the smelting furnace is an electric furnace or a converter.
Preferably, the time of the vacuum refining treatment in the second step is 10-20min.
Preferably, in the second step, the steel ingot is square ingot or octagonal ingot; the liquidus temperature of the casting is 15-40 ℃.
Preferably, the heating temperature of the cast ingot in the third step is more than or equal to 1200 ℃ and the heating time is 3-6 h; the final forging temperature of the forging is 850-880 ℃, the forging opening temperature is 1100-1180 ℃, and the air cooling is carried out after the forging until the surface temperature is 180-280 ℃.
Preferably, the compression ratio of the control material in the forging process in the step three is more than or equal to 6.
Preferably, the heat treatment in the fourth step includes an annealing treatment and a normalizing treatment; the normalizing treatment temperature is 890-920 ℃, and the heat preservation is carried out for 7-9h.
Preferably, the annealing treatment is carried out in an annealing furnace with the temperature of 600-650 ℃, and the treatment process specifically comprises the following steps: after the batch is in a good order, the temperature is raised to 800-830 ℃ at a heating rate of less than or equal to 1.7 ℃/min, and the temperature is kept for 16-20 hours; cooling to 660-700 ℃ at a cooling rate of 0.3-0.7 ℃/min, and preserving heat for 34-42 hours; cooling to 450 deg.c at the speed of 0.3-0.7 deg.c/min and air cooling.
Detailed Description
The following detailed description of the preferred embodiments of the present invention will be provided in connection with.
The ultra-fine grain Cr-Ni-Mo alloy steel forging material is characterized by comprising the following chemical components in percentage by mass: 0.38 to 0.43 percent of C, 0.25 to 0.35 percent of Si, 0.70 to 0.80 percent of Mn, less than or equal to 0.015 percent of S, less than or equal to 0.015 percent of P, 0.80 to 0.85 percent of Cr, 0.30 to 0.35 percent of Mo, 1.70 to 1.95 percent of Ni, 0.020 to 0.050 percent of Al, 90 to 150ppm of N, 0.06 to 0.15 percent of V, and the balance of iron and other unavoidable impurities.
Carbon C:0.38 to 0.43 percent
Carbon C: in the Cr-Ni-Mo alloy steel, C is an element necessary for ensuring the strength of the steel, and the improvement of the C content in the steel increases the unbalanced structure transformation capacity of the steel, so that the strength of the steel is obviously improved; in the invention, diffusion of C element in steel can be inhibited by quenching and tempering heat treatment process to form a tangential martensitic transformation, thereby remarkably improving the strength of the steel. However, for the technical proposal, the content of C element in the steel is not too high, and the excessively high content of C can adversely affect the plasticity and toughness of the steel, and can obviously increase the carbon equivalent of the material, and deteriorate the welding performance of the steel. Based on this, in the high-strength steel material according to the present invention, the content of the element C is controlled to be 0.38 to 0.43 mass%.
Silicon Si:0.25 to 0.35 percent
Silicon Si: in the Cr-Ni-Mo alloy steel, si element can be dissolved in the steel in a solid solution mode and plays a role in solid solution strengthening, and the yield strength, the fatigue strength and the hardness of the steel can be remarkably improved. The solubility of Si in cementite is very low, the content of Si element in steel is not excessively high, when the content of Si element in steel is excessively high, not only a carbide-free bainitic structure is formed, but also the brittleness of the steel is increased. Based on this, in the high-strength steel material according to the present invention, the content of Si element is controlled to be 0.25 to 0.35 mass%.
Manganese Mn:0.70 to 0.80 percent
Manganese Mn: in the Cr-Ni-Mo alloy steel, mn element can improve the stability of austenite in the steel and can also improve the hardenability of the steel. In addition, mn can also increase the strength of martensite in steel by solid solution strengthening, thereby increasing the strength of steel. However, it should be noted that the content of Mn element in the steel is not too high, and when the content of Mn element in the steel is too high, austenite grains are easily grown and segregation of harmful elements in grain boundaries is promoted during quenching and heating. Based on this, in the high-strength steel material according to the present invention, the mass percentage of Mn element is controlled to be 0.70 to 0.80%.
Sulfur S: less than or equal to 0.015 percent/P: less than or equal to 0.015 percent
In the Cr-Ni-Mo alloy steel of the invention, the P element and the S element are both unavoidable harmful impurity elements in the steel and both deteriorate the performance of the steel, so that the P element is controlled to satisfy the following conditions in the invention: p is less than or equal to 0.015 percent, and the S element is controlled to satisfy the following conditions: s is less than or equal to 0.015 percent.
Chromium Cr:0.80 to 0.85 percent
In the Cr-Ni-Mo alloy steel, the addition of a proper amount of Cr element can improve the hardenability of the steel, has the function of secondary hardening, can form a hardened martensitic structure, and is beneficial to improving the strength of the steel. In addition, cr carbide can play a role in inhibiting grain growth, but the content of Cr element in steel is not too high, and when the content of Cr element in steel is too high, a large amount of carbide is generated and aggregated at grain boundaries, so that the toughness of the material is reduced and the carbon equivalent is obviously increased, and the mass percentage of Cr element is controlled to be between 0.8 and 0.85 percent based on the carbide.
Molybdenum Mo:0.30 to 0.35 percent;
in the Cr-Ni-Mo alloy steel, mo element mainly exists in the steel in a solid solution form, so that the Cr-Ni-Mo alloy steel has a solid solution strengthening effect, is beneficial to improving the hardenability of the steel, and enables the steel to form martensite in the quenching process. Mo is also a noble alloying element, and adding excessive Mo also leads to an increase in alloy cost. Based on the above, the mass percentage of Mo element is controlled to be between 0.3 and 0.35 percent.
Nickel Ni:1.70 to 1.95 percent;
in the steel of the present invention, ni is an austenite forming element which is one of the main strengthening elements, can exist in the steel in a solid solution form, can be infinitely solid-dissolved with iron, and can reduce the C content of eutectoid sites by adding an appropriate amount of Ni element to the steel, strengthen ferrite and refine and increase pearlite, and can improve the strength of the steel without significantly affecting the plasticity of the steel. The Ni element can improve the fatigue resistance of the steel, reduce the sensitivity of the steel to the notch, reduce the low-temperature embrittlement transition temperature of the steel and improve the impact toughness of the steel. In addition, the Ni element has less influence on toughness, plasticity and other technological performances of the steel while improving the strength of the steel. Based on this, in the high-strength steel material according to the present invention, the content of Ni element is controlled to be 1.70 to 1.95 mass%.
Aluminum Al:0.020 to 0.050 percent;
in the steel of the present invention, al has the main functions of deoxidizing and fixing nitrogen, and A1N formed by combining A1 and N can effectively refine grains. However, it should be noted that the content of Al element in the steel is not too high, and when the content of Al element in the steel is too high, the casting property of the steel is affected and the toughness of the steel is impaired. Based on this, in the high-strength steel material according to the present invention, the content of Al element is controlled to be 0.02 to 0.05 mass%.
Nitrogen N90-150 ppm
In the high-strength steel material according to the present invention, N is an austenite forming element and also an MX-type precipitate forming element; in order to avoid the enrichment of N element in steel, it is not preferable to add too much N in steel. Therefore, the content of N element must be strictly controlled, and in the high-strength steel material according to the present invention, the content of N element is controlled to be 0.009 to 0.015% by mass.
Vanadium V:0.06 to 0.15 percent
In the steel of the present invention, V is a strong carbide-forming element, and the strength of the steel can be remarkably improved in the form of dispersion precipitation. However, it should be noted that when the addition amount of the V element in the steel is too high, toughness and weldability of the steel are lowered. Based on this, in the high-strength steel material according to the present invention, the content of V element is controlled to be 0.06 to 0.15 mass%.
Another object of the present invention is to provide a method for manufacturing the ultra-fine grain Cr-Ni-Mo alloy steel forging, comprising the steps of:
firstly, adding ingredients according to weight percentage into a smelting furnace, and smelting furnace burden into primary molten steel;
step two, refining outside the furnace: refining the molten steel obtained in the step one into alloy steel through LF and VD or RH vacuum refining treatment, and casting the molten steel into steel ingots by adopting a mold injection process after refining;
step three, forging: forging the alloy steel ingot obtained in the second step, and rolling the obtained ingot after heating to obtain a finished product size;
step four, heat treatment: and (3) placing the forge piece after natural cooling in the step (III) into an annealing furnace for heat treatment.
Preferably, in the first step, the smelting furnace is an electric furnace or a converter.
Preferably, the time of the vacuum refining treatment in the second step is 10-20min.
Preferably, in the second step, the steel ingot is square ingot or octagonal ingot; the liquidus temperature of the casting is 15-40 ℃.
Preferably, the heating temperature of the cast ingot in the third step is more than or equal to 1200 ℃ and the heating time is 3-6 h; the final forging temperature of the forging is 850-880 ℃, the forging opening temperature is 1100-1180 ℃, and the air cooling is carried out after the forging until the surface temperature is 180-280 ℃.
Preferably, the compression ratio of the control material in the forging process in the step three is more than or equal to 6.
The size of the clamp before upsetting the steel ingot is matched with the diameter of the upsetting drain pan, and the clamp is ensured not to be eccentric. The forging temperature is 1100-1180 ℃. In order to avoid the riveting and upsetting phenomenon of the clamping handle in the upsetting process, the extrusion length of the clamping handle before upsetting is preferably 150-200 mm shorter than the height of the leak plate. Cutting off the dead head end of the steel ingot, and cutting off the tail part of the steel ingot is more than or equal to 2 percent. And after the pressing handle is finished, the material is put into a furnace for heat preservation (the temperature is 1180-1200 ℃) for 120-180 minutes. In upsetting, in order to avoid upsetting and bending of materials and double-drum shape in the upsetting process, the ratio of the height of the blank to the diameter is less than or equal to 2.5. Slowly upsetting to 1/2, stopping for 10-20 seconds in the middle, drawing to 530mm square (chamfering is needed), and returning to the furnace for heat preservation (the temperature is 1180-1200 ℃) for 15-40 minutes after chamfering is finished. After the material is discharged from the furnace, the finished product is forged according to the specification of the finished product, and the final forging temperature is 850-880 ℃. Air cooling to 180-280 deg.c after forging.
Preferably, the heat treatment in the fourth step includes an annealing treatment and a normalizing treatment; the normalizing treatment temperature is 890-920 ℃, and the heat preservation is carried out for 7-9h.
Preferably, the annealing treatment is carried out in an annealing furnace with the temperature of 600-650 ℃, and the treatment process specifically comprises the following steps: after the batch is in a good order, the temperature is raised to 800-830 ℃ at a heating rate of less than or equal to 1.7 ℃/min, and the temperature is kept for 16-20 hours; cooling to 660-700 ℃ at a cooling rate of 0.3-0.7 ℃/min, and preserving heat for 34-42 hours; cooling to 450 deg.c at the speed of 0.3-0.7 deg.c/min and air cooling.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages: the superfine grain Cr-Ni-Mo alloy steel forging material provided by the invention has the grain size of more than or equal to 7 grades, has good obdurability matching and structure, and can pass ultrasonic flaw detection inspection with the diameter of 2.5 mm; the manufacturing method is simple and convenient, has low dependency on equipment, high preparation efficiency and low energy consumption, and is suitable for continuous large-scale production.
The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto:
example 1
The example provides an ultrafine grain Cr-Ni-Mo alloy steel forging material, which is characterized by comprising the following chemical components in percentage by mass: 0.38% of C, 0.25% of Si, 0.70% of Mn, less than or equal to 0.015% of S, less than or equal to 0.015% of P, 0.80% of Cr, 0.30% of Mo, 1.70% of Ni, 0.020% of Al, 90ppm of N, 0.06% of V, and the balance of iron and other unavoidable impurities.
The manufacturing method of the superfine grain Cr-Ni-Mo alloy steel forging comprises the following steps:
firstly, adding ingredients according to weight percentage into a smelting furnace, and smelting furnace burden into primary molten steel;
step two, refining outside the furnace: refining the molten steel obtained in the step one by LF and VD vacuum refining treatment to further refine the molten steel into the alloy steel, and casting the molten steel into steel ingots by adopting a mold injection process after refining;
step three, forging: forging the alloy steel ingot obtained in the second step, and rolling the obtained ingot after heating to obtain a finished product size;
step four, heat treatment: and (3) placing the forge piece after natural cooling in the step (III) into an annealing furnace for heat treatment.
The smelting furnace is an electric furnace; the time of the vacuum refining treatment in the second step is 10min; step two, the steel ingot is square; the liquidus temperature of the casting was 15 ℃.
In the third step, the heating temperature of the cast ingot is more than or equal to 1200 ℃ and the heating time is 3 hours; the final forging temperature of the forging is 850 ℃, the forging opening temperature is 1100 ℃, and the air cooling is carried out after the forging until the surface temperature is 180 ℃; and in the third step, the compression ratio of the control material in the forging process is more than or equal to 6.
The heat treatment in the fourth step comprises annealing treatment and normalizing treatment; the temperature of the normalizing treatment is 890 ℃, and the normalizing treatment is kept for 7 hours.
The annealing treatment is carried out in an annealing furnace with the temperature of 600 ℃, and the treatment process comprises the following steps: after the batch is in a good order, the temperature is raised to 800 ℃ for 16 hours at a heating rate of less than or equal to 1.7 ℃/min; cooling to 660 ℃ at a cooling rate of 0.3 ℃/min, and preserving heat for 34 hours; cooling to less than or equal to 450 ℃ at a cooling rate of 0.3 ℃/min, discharging and air cooling.
Example 2
The example provides an ultrafine grain Cr-Ni-Mo alloy steel forging material, which is characterized by comprising the following chemical components in percentage by mass: 0.39% of C, 0.27% of Si, 0.73% of Mn, less than or equal to 0.015% of S, less than or equal to 0.015% of P, 0.82% of Cr, 0.32% of Mo, 1.75% of Ni, 0.030% of Al, 110ppm of N, 0.08% of V, and the balance of iron and other unavoidable impurities.
The manufacturing method of the superfine grain Cr-Ni-Mo alloy steel forging comprises the following steps:
firstly, adding ingredients according to weight percentage into a smelting furnace, and smelting furnace burden into primary molten steel;
step two, refining outside the furnace: refining the molten steel obtained in the step one into alloy steel through LF and RH vacuum refining treatment, and casting the molten steel into steel ingots by adopting a mold injection process after refining;
step three, forging: forging the alloy steel ingot obtained in the second step, and rolling the obtained ingot after heating to obtain a finished product size;
step four, heat treatment: and (3) placing the forge piece after natural cooling in the step (III) into an annealing furnace for heat treatment.
The smelting furnace is a converter; the time of the vacuum refining treatment in the second step is 13min; step two, the steel ingot is a square ingot; the liquidus temperature of the casting is 22 ℃; in the third step, the heating temperature of the cast ingot is more than or equal to 1200 ℃ and the heating time is 4 hours; the final forging temperature of the forging is 860 ℃, the forging opening temperature is 1120 ℃, and the air cooling is carried out after the forging until the surface temperature is 210 ℃; and in the third step, the compression ratio of the control material in the forging process is more than or equal to 6.
The heat treatment in the fourth step comprises annealing treatment and normalizing treatment; the temperature of the normalizing treatment is 900 ℃, and the temperature is kept for 7.5 hours; the annealing treatment is carried out in an annealing furnace with the temperature of 620 ℃, and the treatment process specifically comprises the following steps: after the batch is in a good order, heating to 810 ℃ at a heating rate of less than or equal to 1.7 ℃/min, and preserving heat for 17 hours; cooling to 670 ℃ at a cooling rate of 0.4 ℃/min, and preserving heat for 36 hours; cooling to less than or equal to 450 ℃ at a cooling rate of 0.4 ℃/min, discharging and air cooling.
Example 3
The example provides an ultrafine grain Cr-Ni-Mo alloy steel forging material, which is characterized by comprising the following chemical components in percentage by mass: 0.41% of C, 0.30% of Si, 0.75% of Mn, less than or equal to 0.015% of S, less than or equal to 0.015% of P, 0.83% of Cr, 0.33% of Mo, 1.88% of Ni, 0.035% of Al, 120ppm of N, 0.12% of V, and the balance of iron and other unavoidable impurities.
The manufacturing method of the superfine grain Cr-Ni-Mo alloy steel forging comprises the following steps:
firstly, adding ingredients according to weight percentage into a smelting furnace, and smelting furnace burden into primary molten steel;
step two, refining outside the furnace: refining the molten steel obtained in the step one by LF and VD vacuum refining treatment to further refine the molten steel into the alloy steel, and casting the molten steel into steel ingots by adopting a mold injection process after refining;
step three, forging: forging the alloy steel ingot obtained in the second step, and rolling the obtained ingot after heating to obtain a finished product size;
step four, heat treatment: and (3) placing the forge piece after natural cooling in the step (III) into an annealing furnace for heat treatment.
The smelting furnace is an electric furnace; the time of the vacuum refining treatment in the second step is 15min; step two, the steel ingot is an octagonal ingot; the liquidus temperature of the casting is 30 ℃; in the third step, the heating temperature of the cast ingot is more than or equal to 1200 ℃ and the heating time is 4.5h; the final forging temperature of the forging is 865 ℃, the forging opening temperature is 1150 ℃, and the air cooling is carried out after the forging until the surface temperature is 230 ℃; and in the third step, the compression ratio of the control material in the forging process is more than or equal to 6.
The heat treatment in the fourth step comprises annealing treatment and normalizing treatment; the temperature of the normalizing treatment is 905 ℃, and the temperature is kept for 8 hours; the annealing treatment is carried out in an annealing furnace with the temperature of 630 ℃, and the treatment process comprises the following steps: after the batch is in a good order, the temperature is raised to 815 ℃ for 18 hours at a heating rate of less than or equal to 1.7 ℃/min; cooling to 680 ℃ at a cooling rate of 0.5 ℃/min, and preserving heat for 39 hours; cooling to less than or equal to 450 ℃ at a cooling rate of 0.5 ℃/min, discharging and air cooling.
Example 4
The example provides an ultrafine grain Cr-Ni-Mo alloy steel forging material, which is characterized by comprising the following chemical components in percentage by mass: 0.42% of C, 0.33% of Si, 0.78% of Mn, less than or equal to 0.015% of S, less than or equal to 0.015% of P, 0.84% of Cr, 0.34% of Mo, 1.92% of Ni, 0.04% of Al, 140ppm of N, 0.13% of V, and the balance of iron and other unavoidable impurities.
The manufacturing method of the superfine grain Cr-Ni-Mo alloy steel forging comprises the following steps:
firstly, adding ingredients according to weight percentage into a smelting furnace, and smelting furnace burden into primary molten steel;
step two, refining outside the furnace: refining the molten steel obtained in the step one into alloy steel through LF and RH vacuum refining treatment, and casting the molten steel into steel ingots by adopting a mold injection process after refining;
step three, forging: forging the alloy steel ingot obtained in the second step, and rolling the obtained ingot after heating to obtain a finished product size;
step four, heat treatment: and (3) placing the forge piece after natural cooling in the step (III) into an annealing furnace for heat treatment.
The smelting furnace is a converter; the time of the vacuum refining treatment in the second step is 18min; step two, the steel ingot is an octagonal ingot; the liquidus temperature of the casting is 35 ℃; in the third step, the heating temperature of the cast ingot is more than or equal to 1200 ℃ and the heating time is 5.5h; the final forging temperature of the forging is 875 ℃, the forging opening temperature is 1170 ℃, and the air cooling is carried out after the forging until the surface temperature is 260 ℃.
In the third step, the compression ratio of the control material in the forging process is more than or equal to 6; the heat treatment in the fourth step comprises annealing treatment and normalizing treatment; the temperature of the normalizing treatment is 910 ℃, and the temperature is kept for 8.5 hours; the annealing treatment is carried out in an annealing furnace with the temperature of 640 ℃, and the treatment process specifically comprises the following steps: after the batch is in a good order, the temperature is raised to 825 ℃ for 19 hours at a heating rate of less than or equal to 1.7 ℃/min; cooling to 695 ℃ at a cooling rate of 0.6 ℃/min, and preserving heat for 41 hours; cooling to less than or equal to 450 ℃ at a cooling rate of 0.6 ℃/min, discharging and air cooling.
Example 5
The example provides an ultrafine grain Cr-Ni-Mo alloy steel forging material, which is characterized by comprising the following chemical components in percentage by mass: 0.43% of C, 0.35% of Si, 0.80% of Mn, less than or equal to 0.015% of S, less than or equal to 0.015% of P, 0.85% of Cr, 0.35% of Mo, 1.95% of Ni, 0.050% of Al, 150ppm of N, 0.15% of V, and the balance of iron and other unavoidable impurities.
The manufacturing method of the superfine grain Cr-Ni-Mo alloy steel forging comprises the following steps:
firstly, adding ingredients according to weight percentage into a smelting furnace, and smelting furnace burden into primary molten steel;
step two, refining outside the furnace: refining the molten steel obtained in the step one by LF and VD vacuum refining treatment to further refine the molten steel into the alloy steel, and casting the molten steel into steel ingots by adopting a mold injection process after refining;
step three, forging: forging the alloy steel ingot obtained in the second step, and rolling the obtained ingot after heating to obtain a finished product size;
step four, heat treatment: and (3) placing the forge piece after natural cooling in the step (III) into an annealing furnace for heat treatment.
The smelting furnace is an electric furnace; the time of the vacuum refining treatment in the second step is 20min; step two, the steel ingot is an octagonal ingot; the liquidus temperature of the casting is 40 ℃; in the third step, the heating temperature of the cast ingot is more than or equal to 1200 ℃ and the heating time is 6 hours; the final forging temperature of the forging is 880 ℃, the forging opening temperature is 1180 ℃, and the air cooling is carried out after the forging until the surface temperature is 280 ℃.
In the third step, the compression ratio of the control material in the forging process is more than or equal to 6; the heat treatment in the fourth step comprises annealing treatment and normalizing treatment; the temperature of the normalizing treatment is 920 ℃, and the temperature is kept for 9 hours; the annealing treatment is carried out in an annealing furnace with the temperature of 650 ℃, and the treatment process comprises the following steps: after the batch is in a good order, the temperature is raised to 830 ℃ for 20 hours at a heating rate of less than or equal to 1.7 ℃/min; cooling to 700 ℃ at a cooling rate of 0.7 ℃/min, and preserving heat for 42 hours; cooling to less than or equal to 450 ℃ at a cooling rate of 0.7 ℃/min, discharging and air cooling.
Comparative example 1
This example provides an ultra-fine grain Cr-Ni-Mo alloy steel forging, which is substantially the same as example 1 except that Si and Al are not added and that the liquidus temperature of the casting is 60 ℃.
Comparative example 2
This example provides an ultra-fine grain Cr-Ni-Mo alloy steel forging, which is substantially the same as example 1 except that Mn and V are not added and the liquidus temperature of the casting is 10 ℃.
In order to further illustrate the beneficial technical effects of the Cr-Ni-Mo alloy steel forging material with ultrafine grains, the products with various examples are subjected to relevant performance tests, the test results are shown in Table 1, and the test method is as follows: the grain size is measured according to GB/T6394 method for measuring average grain size of metals; tensile strength was measured according to GB/T228.1-2021.
TABLE 1
Project Tensile Strength Grain size of
Unit (B) MPa ％
Example 1 727 7
Example 2 745 7
Example 3 768 8
Example 4 780 8
Example 5 793 8
Comparative example 1 656 5
Comparative example 2 639 5
As can be seen from Table 1, the ultra-fine grain Cr-Ni-Mo alloy steel forging material in the example of the present invention has higher mechanical properties, and finer grains, and reasonable control of the addition and casting temperatures of Si, al, mn and V is beneficial to improving the above properties.
The above embodiments are provided for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the present invention and to implement the same, but are not intended to limit the scope of the present invention, and all equivalent changes or modifications according to the spirit of the present invention should be included in the scope of the present invention.

Claims (9)

1. The ultra-fine grain Cr-Ni-Mo alloy steel forging material is characterized by comprising the following chemical components in percentage by mass: 0.38 to 0.43 percent of C, 0.25 to 0.35 percent of Si, 0.70 to 0.80 percent of Mn, less than or equal to 0.015 percent of S, less than or equal to 0.015 percent of P, 0.80 to 0.85 percent of Cr, 0.30 to 0.35 percent of Mo, 1.70 to 1.95 percent of Ni, 0.020 to 0.050 percent of Al, 90 to 150ppm of N, 0.06 to 0.15 percent of V, and the balance of iron and other unavoidable impurities.
2. A method for manufacturing an ultra fine grain Cr-Ni-Mo alloy steel forging according to claim 1, comprising the steps of:
firstly, adding ingredients according to weight percentage into a smelting furnace, and smelting furnace burden into primary molten steel;
step two, refining outside the furnace: refining the molten steel obtained in the step one into alloy steel through LF and VD or RH vacuum refining treatment, and casting the molten steel into steel ingots by adopting a mold injection process after refining;
step three, forging: forging the alloy steel ingot obtained in the second step, and rolling the obtained ingot after heating to obtain a finished product size;
step four, heat treatment: and (3) placing the forge piece after natural cooling in the step (III) into an annealing furnace for heat treatment.
3. The method for producing an ultra-fine grain Cr-Ni-Mo alloy steel wrought material according to claim 2, wherein the smelting furnace in the step one is an electric furnace or a converter.
4. The method for manufacturing an ultra-fine grain Cr-Ni-Mo alloy steel forged material according to claim 2, wherein the time of the vacuum refining treatment in the second step is 10 to 20 minutes.
5. The method for manufacturing an ultra-fine grain Cr-Ni-Mo alloy steel forging according to claim 2, wherein in the second step, the steel ingot is a square ingot or an octagonal ingot; the liquidus temperature of the casting is 15-40 ℃.
6. The method for manufacturing an ultra-fine grain Cr-Ni-Mo alloy steel forging according to claim 2, wherein the heating temperature of the ingot in the third step is not less than 1200 ℃ and the heating time is 3-6 hours; the final forging temperature of the forging is 850-880 ℃, the forging opening temperature is 1100-1180 ℃, and the air cooling is carried out after the forging until the surface temperature is 180-280 ℃.
7. The method for manufacturing an ultra-fine grain Cr-Ni-Mo alloy steel forging according to claim 2, wherein the compression ratio of the control material in the forging process in step three is not less than 6.
8. The method for manufacturing an ultra-fine grain Cr-Ni-Mo alloy steel forged material according to claim 2, wherein the heat treatment in the fourth step includes an annealing treatment and a normalizing treatment; the normalizing treatment temperature is 890-920 ℃, and the heat preservation is carried out for 7-9h.
9. The method for manufacturing an ultra-fine grain Cr-Ni-Mo alloy steel forging according to claim 2, wherein the annealing treatment is performed in an annealing furnace at 600-650 ℃, and the treatment process is specifically: after the batch is in a good order, the temperature is raised to 800-830 ℃ at a heating rate of less than or equal to 1.7 ℃/min, and the temperature is kept for 16-20 hours; cooling to 660-700 ℃ at a cooling rate of 0.3-0.7 ℃/min, and preserving heat for 34-42 hours; cooling to 450 deg.c at the speed of 0.3-0.7 deg.c/min and air cooling.
CN202311429698.4A 2023-10-31 2023-10-31 Ultra-fine grain Cr-Ni-Mo alloy steel forging material and manufacturing method thereof Pending CN117448682A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311429698.4A CN117448682A (en) 2023-10-31 2023-10-31 Ultra-fine grain Cr-Ni-Mo alloy steel forging material and manufacturing method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311429698.4A CN117448682A (en) 2023-10-31 2023-10-31 Ultra-fine grain Cr-Ni-Mo alloy steel forging material and manufacturing method thereof

Publications (1)

Publication Number Publication Date
CN117448682A true CN117448682A (en) 2024-01-26

Family

ID=89592489

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311429698.4A Pending CN117448682A (en) 2023-10-31 2023-10-31 Ultra-fine grain Cr-Ni-Mo alloy steel forging material and manufacturing method thereof

Country Status (1)

Country Link
CN (1) CN117448682A (en)

Similar Documents

Publication Publication Date Title
CN110079740B (en) High-toughness hot-rolled 530 MPa-grade automobile cold-stamped axle housing steel plate and manufacturing method thereof
CN101481780B (en) Easy-to-weld superfine austenite crystal steel with superhigh intensity and high tenacity and manufacturing method thereof
CN101701316B (en) Automobile beam steel with tensile strength of 590MPa and manufacturing method thereof
WO2015197007A1 (en) Carburized alloy steel, method for preparing same, and use thereof
CN106987771B (en) A kind of extremely low yield strength steel plate and its production method
CN109763078B (en) Heat-resistant alloy carburizing steel and preparation method thereof
CN111254354A (en) V microalloyed high-strength high-toughness bainite non-quenched and tempered steel and forging and cooling control process and production process thereof
CN109252107B (en) Production method of high-flatness ultrahigh-strength steel
CN112813345A (en) Non-quenched and tempered steel for cold machining engineering machinery hydraulic piston rod and preparation method
CN111349856A (en) Cold heading steel wire rod for ultrahigh-strength lock rivet and preparation method thereof
CN110129673A (en) A kind of 800MPa grades of high strength and ductility Q&P steel plate and preparation method thereof
CN108950387A (en) With excellent high performance think gauge nuclear power safety injection tank steel and its manufacturing method
WO2021208181A1 (en) Low-temperature, high-toughness, high-temperature, high-intensity and high-hardenability hot mold steel and preparation method therefor
CN105543666B (en) A kind of yield strength 960MPa beam steels and its production method
CN101619419A (en) Steel plate for low-carbon high-niobium high strength welding structure and method for manufacturing same
CN113416902B (en) Low-cost thermal-forming axle housing steel plate with yield strength of 460MPa and preparation method thereof
CN113737099A (en) Tool steel suitable for large-deformation cold machining forming and preparation method thereof, and sleeve and preparation method thereof
CN109136759A (en) Spoke 1300MPa grades of hot forming steel of think gauge and preparation method
CN113073260A (en) Steel for high-plasticity cold-roll forming with tensile strength of 500MPa and production method thereof
CN115747678B (en) Steel for high-strength bolt for wind power and high-strength bolt for wind power
CN114990432B (en) Hot rolled strip steel with tensile strength not lower than 1500MPa produced by TSR production line and method
CN109972058A (en) A kind of air-cooled reinforcing steel of automobile cold-rolled low-alloy high-strength and preparation method
CN110331344A (en) A kind of Rm >=600MPa beam steel that strength character is stable and production method
CN112981238B (en) Standard Q460D steel plate for forge piece production by continuous casting billet and manufacturing method thereof
CN115125448A (en) Non-quenched and tempered steel for cold machining of hydraulic piston rod and preparation method

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