CN110846563B - Heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 - Google Patents
Heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 Download PDFInfo
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Abstract
The invention provides a heat treatment process for grain refinement of X12CrMoWVNbN10-1-1, which is characterized in that the amount of needle-shaped austenite is reduced as much as possible and the amount of spherical austenite is increased by increasing the heating speed, so that the grains are refined, the grain size meets the technical requirement, and the application range of X12CrMoWVNbN10-1-1 is expanded. The blanked material is forged to form a workpiece, then the workpiece is subjected to high-temperature normalizing, high-temperature tempering, conventional normalizing and high-temperature tempering in sequence, and then the workpiece subjected to high-temperature tempering is subjected to subsequent processing treatment. In the high-temperature normalizing process, the heating rate of the workpiece in an alpha + gamma double-phase region is increased, so that the workpiece quickly passes through the double-phase region to obtain spherical austenite as much as possible, and on one hand, the crystallographic orientation relation, namely the K-S relation, is broken to a greater extent; on the other hand, the heating speed is increased, so that the nucleation rate of austenite can be increased; the specific process of high-temperature tempering is that the temperature is kept for 15-20 hours in an environment with the temperature of 700 ℃, carbides are precipitated as much as possible, the metallological orientation relation is further destroyed, and then air cooling is carried out.
Description
Technical Field
The invention relates to the technical field of material heat treatment, in particular to a heat treatment process for grain refinement of X12CrMoWVNbN 10-1-1.
Background
The forging manufacturing industry is the basic industry of the national equipment manufacturing industry, is also the strategic industry which is indispensable and is related to national safety and national economic life, and is also the important composition of national capability, and the development level of the large-scale forging is an important mark for measuring the national comprehensive capability.
With the rapid development of industries such as domestic and foreign electric power, petrochemical industry and the like, new technologies and new equipment are developed, and new materials are adopted; meanwhile, new requirements are put forward to the forging industry, so that continuous upgrading and updating of forging equipment are promoted, and generation of a plurality of new technologies and new processes in the forging industry is accelerated.
At present, the technical level of large forgings in China has a quite large gap compared with developed countries in the world, and the problem that certain market requirements in China cannot be met is not only the problem of equipment capacity but also the more central technical problem. The key to whether the large forging industry in China can be continuously and stably developed and can replace large forgings in China lies in whether the core manufacturing technology is mastered and whether the independent innovation capability is provided while enough capacity is provided. Therefore, the technical research and development become an important factor of enterprise competitive position in the large forging manufacturing industry. Qualified high-quality large forgings can be manufactured only by improving the process level through the improvement of the working procedures of smelting, forging, heat treatment and the like; can really become a strong country for producing large-scale steel forgings.
The X12CrMoWVNbN10-1-1 steel belongs to martensite heat-resistant steel and is mainly used for power station equipment and other workpieces which have higher use temperature and require certain corrosion resistance and oxidation resistance, such as high-pressure steam pipelines and reheat hot steam pipelines on boilers, flanges, valve discs, valve bodies and the like. Due to the problem of atmospheric pollution, the requirements on environmental protection are higher and higher, the requirements on power station equipment are also higher and tighter, in order to reduce the pollution to the atmosphere, the power station equipment is developed into ultra supercritical and new ultra supercritical, and the use temperature reaches or exceeds 620 ℃; small power station units which can not meet new emission standards and have serious air pollution are eliminated at home and abroad, and large units with small pollution and high heat efficiency are developed; the increase of unit operation parameters (temperature and pressure) and single unit capacity requires the development of steel with better endurance strength, thermal fatigue resistance and creep resistance, supercritical and supercritical steel such as F91 and F92 are eliminated, and X12CrMoWVNbN10-1-1 martensite heat-resistant steel capable of meeting higher requirements is used more and more.
The X12CrMoWVNbN10-1-1 steel has good high-temperature strength and creep resistance, can effectively reduce the mass of parts such as boilers, pipelines and the like, and improves the thermal fatigue resistance, and has good thermal conductivity and lower expansion rate compared with other austenitic stainless steels, so that the X12CrMoWVNbN10-1-1 steel forge piece is more and more used in the future.
X12CrMoWVNbN10-1-1 has many problems in the actual production process, such as: the crystal grains are coarse. However, since this material contains a large amount of alloying elements and many strong carbide-forming elements, it has very good hardenability and very tough tissue inheritance, and therefore, after the grains become coarse, it is difficult to refine the grain size, and the difficulty of refining the grains is significantly higher than that of martensitic heat-resistant steels such as SA336F91 and SA336F 92.
The existing heat treatment process of the refined crystal grains of the X12CrMoWVNbN10-1-1 steel comprises normalizing, high-temperature tempering, high-temperature normalizing and high-temperature tempering, and then the conventional normalizing, high-temperature tempering and complete annealing are adopted, so that the effect is poor, the grain size can be only improved by 0.5 grade, the crystal grains are coarse, the grain boundary area is reduced, and the concentrations of carbide and nitride are relatively increased, thereby increasing the sensitivity of tempering brittleness; moreover, after the crystal grains are coarse, the path of crack propagation is relatively straight and simple, so that the absorption of energy is reduced, and the impact absorption power is obviously influenced, and an effective solution is not provided at present, so that the problem of coarsening the grain size of the X12CrMoWVNbN10-1-1 steel forging becomes an urgent subject.
Disclosure of Invention
Aiming at the problems, the invention provides a heat treatment process for refining X12CrMoWVNbN10-1-1 grains, which is characterized in that the amount of needle-shaped austenite is reduced as much as possible and the amount of spherical austenite is increased by increasing the heating speed, so that the grains are refined, the grain size meets the technical requirement, and the application range of X12CrMoWVNbN10-1-1 is expanded.
The heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 is characterized by comprising the following steps: forging the blanked material to form a workpiece, sequentially carrying out high-temperature normalizing, high-temperature tempering, conventional normalizing and high-temperature tempering on the workpiece, and then carrying out subsequent processing treatment on the high-temperature tempered workpiece;
in the high-temperature normalizing process, the heating rate of the workpiece in an alpha + gamma double-phase region is increased, so that the workpiece quickly passes through the double-phase region to obtain spherical austenite as much as possible, and on one hand, the crystallographic orientation relation, namely the K-S relation, is broken to a greater extent; on the other hand, the heating speed is increased, so that the nucleation rate of austenite can be increased;
the specific process of the high-temperature tempering is that the temperature is kept for 15-20 hours in an environment with the temperature of 700 ℃, carbides are precipitated as much as possible, the metallological orientation relation is further destroyed, and then air cooling is carried out.
It is further characterized in that: the final mass percentage of each element of the material after controlling the chemical components is as follows, carbon C: 0.11 to 0.13%, Si: less than or equal to 0.12 percent, manganese Mn: 0.40 to 0.50%, phosphorus P: less than or equal to 0.010 percent, sulfur S: less than or equal to 0.005 percent, chromium Cr: 10.20 to 10.80%, molybdenum Mo: 1.00-1.10%, Ni: 0.70-0.80%, Cu: less than or equal to 0.15 percent, vanadium V: 0.15 to 0.25%, Nb: 0.04-0.06%, N: 0.045-0.060%, B: 0.0010-0.0060%, tungsten W: 0.95-1.05%, aluminum Al: less than or equal to 0.010 percent, and the balance of Fe, wherein the sum of the percentages of the elements is 100 percent;
preheating for 2-3 hours in an environment with the temperature of 650 ℃, then heating the environment to 790 ℃, preserving heat for 10-15 hours to ensure thorough burning of the workpiece, then heating with the maximum power of a heat treatment furnace to ensure that the workpiece quickly passes through an alpha + gamma double-phase region to obtain spherical austenite as much as possible, destroying the metal orientation relation, then preserving heat for 6-8 hours in the environment with the temperature of 1080-1110 ℃, adjusting the temperature between 1080 and 1110 ℃ to obtain the most appropriate austenitizing temperature, and then furnace cooling or air cooling the workpiece;
the specific process flow of the conventional normalizing is as follows, preheating a workpiece for 2-3h in an environment with the temperature of 650 ℃; heating to 790 ℃, preserving heat for 10-15h to ensure thorough burning of the workpiece, then heating at the maximum power of a heat treatment furnace, enabling the workpiece to rapidly pass through an alpha + gamma double-phase region to obtain spherical austenite as much as possible, destroying the metal orientation relation, then preserving heat for 6-8h at 950-1000 ℃ and adjusting the temperature between 950-1000 ℃ to obtain the most appropriate austenitizing temperature, and then carrying out furnace cooling or air cooling on the workpiece;
the temperature rise speed of the maximum power temperature rise of the heat treatment furnace is more than 220 ℃/h;
the subsequent processing treatment comprises rough machining, quenching, tempering, sampling, sample processing, tensile test and Charpy impact test, test report and technical analysis.
It is further characterized in that:
when two heat treatment normalizing high-temperature furnaces are adopted for carrying out the heat treatment process, the specific process flow is as follows:
1, preheating: keeping the temperature at 650 ℃ for 2-3 h; heating to 790 ℃, and preserving heat for 10-12h to ensure thorough burning of the workpiece;
2, carrying out high-temperature normalizing by a first heat treatment normalizing high-temperature furnace: heating the furnace to 1080-1110 ℃ in advance, preserving heat for at least 2.5 hours at the temperature, then transferring the preheated and completely burnt workpiece into the furnace, rapidly heating up at the maximum power, passing the workpiece through an alpha + gamma two-phase region at the heating speed as fast as possible, then heating to 1080-1110 ℃ and preserving heat for 6-8 hours, and cooling in the furnace or air; adjusting the temperature between 1080-1110 ℃ to select the most appropriate austenitizing temperature;
3, high-temperature tempering: keeping the temperature at 700 ℃ for 15-20h, and cooling in air;
4, preheating: keeping the temperature at 650 ℃ for 2-3 h; heating to 790 ℃, and preserving the temperature for 10-12h, wherein thorough burning is guaranteed;
and 5, carrying out conventional normalizing by a second heat treatment normalizing high-temperature furnace: heating the furnace to 950-fold-plus-minus 1000 ℃ in advance, preserving heat for at least 2.5h at the temperature, then transferring the preheated and completely-burnt workpiece into the furnace, rapidly heating the workpiece to 950-fold-plus-minus 1000 ℃ by the maximum power, preserving heat for 6-8h by rapidly passing through an alpha + gamma double-phase region, and cooling the furnace or air; adjusting the temperature between 950 and 1000 to obtain the most appropriate austenitizing temperature;
6, high-temperature tempering: keeping the temperature at 700 ℃ for 12-15h, and cooling in air;
when two heat treatment normalizing high-temperature furnaces are adopted for carrying out the heat treatment process, enough other workpieces are reserved in each heat treatment normalizing high-temperature furnace, and the workpieces are in a through-burning state at the corresponding furnace temperature.
The heat treatment process of X12CrMoWVNbN10-1-1 steel refined grains in the prior art comprises normalizing, high-temperature tempering, high-temperature normalizing and high-temperature tempering, then the conventional normalizing, high-temperature tempering, complete annealing and the like are adopted, the effect is poor, the grain size can be only improved by 0.5 grade, and the effect is not ideal because the alloy element content of the X12CrMoWVNbN10-1-1 steel is higher, the hardenability is very good, the tissue inheritance is very stubborn, the tissues obtained by the normalizing, the high-temperature tempering and the complete annealing are non-equilibrium tissues, namely lath martensite tissues, the tissue inheritance is not damaged, namely the K-S relationship is not changed, and the point is proved by metallographic analysis; still another reason is that the workpiece is larger, the heating speed is insufficient, the temperature rising speed in the alpha + gamma double-phase region is slower, the amount of the obtained needle-shaped austenite is larger, the generated spherical austenite is less, the needle-shaped austenite engulfs the spherical austenite, and the metallurgical orientation relationship is not changed; the small sample has very good effect of grain refinement, namely, the small sample has small section size, the surface and the core almost reach the required temperature at the same time, and can pass through an alpha + gamma double-phase region at very high speed, so the effect is very good; according to the invention, the heating speed of the workpiece in an alpha + gamma double-phase region is increased in high-temperature normalizing and conventional normalizing, the spherical austenite is obtained as far as possible by quickly passing through the double-phase region, and on one hand, the crystallographic orientation relation, namely the K-S relation, can be broken to a greater extent; on the other hand, increasing the heating rate can increase the nucleation rate of austenite; the combined process of high-temperature normalizing and high-temperature tempering properly improves the austenitizing temperature of heat treatment, on one hand, alloy elements are diffused as much as possible, on the other hand, carbides and the like which play a role in nailing and binding are dissolved as much as possible, the pinning effect of the carbides and nitrides is removed, then, the mixture is cooled slowly, the alloy elements are precipitated slowly and uniformly, the carbides and the nitrides of the alloy elements are distributed uniformly again in fine and dispersed mass points, and the preparation work is well prepared for the next heat treatment process; the grain size problem is further solved by conventional normalizing and high-temperature tempering; the grain is refined through a combined process, the grain size meets the technical requirement, the X12CrMoWVNbN10-1-1 steel has enough high-temperature strength resistance, high corrosion resistance, high oxidation resistance, good thermal fatigue resistance and good creep resistance, and the application range of the X12CrMoWVNbN10-1-1 steel is expanded.
Detailed Description
The heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 comprises the following steps: forging the blanked material to form a workpiece, sequentially carrying out high-temperature normalizing, high-temperature tempering, conventional normalizing and high-temperature tempering on the workpiece, and then carrying out subsequent processing treatment on the high-temperature tempered workpiece;
in the high-temperature normalizing process, the heating rate of the workpiece in an alpha + gamma double-phase region is increased, so that the workpiece quickly passes through the double-phase region to obtain spherical austenite as much as possible, and on one hand, the crystallographic orientation relation, namely the K-S relation, is broken to a greater extent; on the other hand, the heating speed is increased, so that the nucleation rate of austenite can be increased;
the specific process of high-temperature tempering is that the temperature is kept for 15-20 hours in an environment with the temperature of 700 ℃, carbides are precipitated as much as possible, the metallological orientation relation is further destroyed, and then air cooling is carried out.
The final mass percentage of each element after the chemical composition of the material is controlled is as follows, carbon C: 0.11 to 0.13%, Si: less than or equal to 0.12 percent, manganese Mn: 0.40 to 0.50%, phosphorus P: less than or equal to 0.010 percent, sulfur S: less than or equal to 0.005 percent, chromium Cr: 10.20 to 10.80%, molybdenum Mo: 1.00-1.10%, Ni: 0.70-0.80%, Cu: less than or equal to 0.15 percent, vanadium V: 0.15 to 0.25%, Nb: 0.04-0.06%, N: 0.045-0.060%, B: 0.0010-0.0060%, tungsten W: 0.95-1.05%, aluminum Al: less than or equal to 0.010 percent, and the balance of Fe, wherein the sum of the percentages of the elements is 100 percent;
the specific process flow of the high-temperature normalizing is as follows, preheating is carried out for 2-3h in an environment with the temperature of 650 ℃, then the environment temperature is heated to 790 ℃, heat preservation is carried out for 10-15h, the workpiece is ensured to be fully burnt, then the temperature is raised with the maximum power of a heat treatment furnace, the workpiece rapidly passes through an alpha + gamma double-phase region, as much spherical austenite as possible is obtained, the metal orientation relation is destroyed, then the workpiece is subjected to heat preservation for 6-8h in the environment with the temperature of 1080-1110 ℃, the temperature is adjusted between 1080 and 1110 ℃, so that the most appropriate austenitizing temperature is obtained, and then the workpiece is subjected to furnace cooling or air cooling;
the specific process flow of the conventional normalizing is as follows, preheating a workpiece for 2-3h in an environment with the temperature of 650 ℃; heating to 790 ℃, preserving heat for 10-15h to ensure thorough burning of the workpiece, then heating at the maximum power of a heat treatment furnace, enabling the workpiece to rapidly pass through an alpha + gamma double-phase region to obtain spherical austenite as much as possible, destroying the metal orientation relation, then preserving heat for 6-8h at 950-1000 ℃ and adjusting the temperature between 950-1000 ℃ to obtain the most appropriate austenitizing temperature, and then carrying out furnace cooling or air cooling on the workpiece;
the temperature rise speed of the maximum power temperature rise of the heat treatment furnace is more than 220 ℃/h;
the subsequent processing treatment comprises rough machining, quenching, tempering, sampling, sample processing, tensile test and Charpy impact test, test report and technical analysis.
The first embodiment is as follows: when one heat treatment furnace is adopted, the specific process flow is as follows:
1, high-temperature normalizing: preheating for 2-3h at 650 ℃; heating to 790 ℃, and preserving heat for 10-15h to ensure that the workpiece is completely burnt; then heating up by the maximum power of the heat treatment furnace, rapidly passing through an alpha + gamma double-phase region to obtain spherical austenite as much as possible, destroying the metallographical orientation relationship, preserving heat for 6-8h at 1080-1110 ℃, and cooling in the furnace or in the air; adjusting the temperature between 1080-1110 ℃ to obtain the most appropriate austenitizing temperature;
2, high-temperature tempering: keeping the temperature at 700 ℃ for 15-20h to separate out carbide as much as possible, further destroying the metallology orientation relation, and cooling in air;
3, conventional normalizing: preheating for 2-3h at 650 ℃; heating to 790 ℃, and preserving heat for 10-15h, wherein the thorough burning of the workpiece must be ensured. Then heating up by the maximum power of the heat treatment furnace, passing through an alpha + gamma double-phase region as fast as possible to obtain spherical austenite as much as possible, destroying the metal orientation relation, adjusting the temperature between 950 + 10 ℃ and 950 + 1000 ℃ to obtain the most appropriate austenitizing temperature, and preserving the heat for 6-8 h; furnace cooling or air cooling;
4, high-temperature tempering: keeping the temperature at 700 ℃ for 10-15 h.
Specific example two:
when two heat treatment normalizing high-temperature furnaces are adopted for carrying out the heat treatment process, the specific process flow is as follows:
1, preheating: keeping the temperature at 650 ℃ for 2-3 h; heating to 790 ℃, and preserving heat for 10-12h to ensure thorough burning of the workpiece;
2, carrying out high-temperature normalizing by a first heat treatment normalizing high-temperature furnace: heating the furnace to 1080-1110 ℃ in advance, preserving heat for at least 2.5 hours at the temperature, then transferring the preheated and completely burnt workpiece into the furnace, rapidly heating up at the maximum power, passing the workpiece through an alpha + gamma two-phase region at the heating speed as fast as possible, then heating to 1080-1110 ℃ and preserving heat for 6-8 hours, and cooling in the furnace or air; adjusting the temperature between 1080-1110 ℃ to select the most appropriate austenitizing temperature;
3, high-temperature tempering: keeping the temperature at 700 ℃ for 15-20h, and cooling in air;
4, preheating: keeping the temperature at 650 ℃ for 2-3 h; heating to 790 ℃, and preserving the temperature for 10-12h, wherein thorough burning is guaranteed;
and 5, carrying out conventional normalizing by a second heat treatment normalizing high-temperature furnace: heating the furnace to 950-fold-plus-minus 1000 ℃ in advance, preserving heat for at least 2.5h at the temperature, then transferring the preheated and completely-burnt workpiece into the furnace, rapidly heating the workpiece to 950-fold-plus-minus 1000 ℃ by the maximum power, preserving heat for 6-8h by rapidly passing through an alpha + gamma double-phase region, and cooling the furnace or air; adjusting the temperature between 950 and 1000 to obtain the most appropriate austenitizing temperature;
6, high-temperature tempering: keeping the temperature at 700 ℃ for 12-15h, and cooling in air;
specific example three: when the heat treatment process is performed using two heat treatment normalizing high-temperature furnaces as in the second embodiment, a sufficient number of other workpieces remain in each heat treatment normalizing high-temperature furnace, and these workpieces are in a through-fired state at the corresponding furnace temperature (the process and heat treatment parameters are as in the second embodiment).
The heat treatment process of X12CrMoWVNbN10-1-1 steel refined grains in the prior art comprises normalizing, high-temperature tempering, high-temperature normalizing and high-temperature tempering, then the conventional normalizing, high-temperature tempering and complete annealing are adopted, the effect is poor, the grain size can be only improved by 0.5 grade, and the effect is not ideal because the alloy element content of the X12CrMoWVNbN10-1-1 steel is higher, the hardenability is very good, the tissue inheritance is very stubborn, the tissue obtained by the normalizing, high-temperature tempering or complete annealing is a non-equilibrium tissue, namely a lath martensite tissue, the tissue inheritance is not damaged, namely the K-S relationship is not changed, and the point is proved to be obtained by metallographic analysis; still another reason is that the workpiece is larger, the heating speed is insufficient, the temperature rising speed in the alpha + gamma double-phase region is slower, the amount of the obtained needle-shaped austenite is larger, the generated spherical austenite is less, the needle-shaped austenite engulfs the spherical austenite, and the metallurgical orientation relationship is not changed; the small sample has very good effect of grain refinement, namely, the small sample has small section size, the surface and the core almost reach the required temperature at the same time, and can pass through an alpha + gamma double-phase region at very high speed, so the effect is very good.
According to the invention, the heating speed of the workpiece in an alpha + gamma double-phase region is increased in high-temperature normalizing and conventional normalizing, the spherical austenite is obtained as far as possible by quickly passing through the double-phase region, and on one hand, the crystallographic orientation relation, namely the K-S relation, can be broken to a greater extent; on the other hand, increasing the heating rate can increase the nucleation rate of austenite; the combined process of high-temperature normalizing and high-temperature tempering properly improves the austenitizing temperature of heat treatment, on one hand, alloy elements are diffused as much as possible, on the other hand, carbides and the like which play a role in nailing and binding are dissolved as much as possible, the pinning effect of the carbides and nitrides is removed, then, the mixture is cooled slowly, the alloy elements are precipitated slowly and uniformly, the carbides and the nitrides of the alloy elements are distributed uniformly again in fine and dispersed mass points, and the preparation work is well prepared for the next heat treatment process; the grain size problem is further solved by conventional normalizing and high-temperature tempering; the grain is refined through a combined process, the grain size meets the technical requirement, the X12CrMoWVNbN10-1-1 steel has enough high-temperature strength resistance, high corrosion resistance, high oxidation resistance, good thermal fatigue resistance and good creep resistance, and the application range of the X12CrMoWVNbN10-1-1 steel is expanded.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (5)
- The heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 is characterized by comprising the following steps: forging the blanked material to form a workpiece, sequentially carrying out high-temperature normalizing, high-temperature tempering, conventional normalizing and high-temperature tempering on the workpiece, and then carrying out subsequent processing treatment on the high-temperature tempered workpiece;in the high-temperature normalizing process, the heating rate of the workpiece in an alpha + gamma double-phase region is increased, so that the workpiece quickly passes through the double-phase region to obtain spherical austenite as much as possible, and on one hand, the crystallographic orientation relation, namely the K-S relation, is broken to a greater extent; on the other hand, the heating speed is increased, so that the nucleation rate of austenite can be increased;preheating for 2-3 hours in an environment with the temperature of 650 ℃, then heating the environment to 790 ℃, preserving heat for 10-15 hours to ensure thorough burning of the workpiece, then heating with the maximum power of a heat treatment furnace to ensure that the workpiece quickly passes through an alpha + gamma double-phase region to obtain spherical austenite as much as possible, destroying the metal orientation relation, then preserving heat for 6-8 hours in the environment with the temperature of 1080-1110 ℃, adjusting the temperature between 1080 and 1110 ℃ to obtain the most appropriate austenitizing temperature, and then furnace cooling or air cooling the workpiece;the specific process of the high-temperature tempering is that the temperature is kept for 15-20 hours in an environment with the temperature of 700 ℃, so that carbides are precipitated as much as possible, the metallological orientation relation is further destroyed, and then the air cooling is carried out;the specific process flow of the conventional normalizing is as follows, preheating a workpiece for 2-3h in an environment with the temperature of 650 ℃; heating to 790 ℃, preserving heat for 10-15h to ensure thorough burning of the workpiece, then heating at the maximum power of a heat treatment furnace, enabling the workpiece to rapidly pass through an alpha + gamma double-phase region to obtain spherical austenite as much as possible, destroying the metal orientation relation, then preserving heat for 6-8h at 950-1000 ℃ and adjusting the temperature between 950-1000 ℃ to obtain the most appropriate austenitizing temperature, and then carrying out furnace cooling or air cooling on the workpiece; the temperature rise speed of the maximum power temperature rise of the heat treatment furnace is more than 220 ℃/h.
- 2. The heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 as claimed in claim 1, wherein: the final mass percentage of each element of the material after controlling the chemical components is as follows, carbon C: 0.11 to 0.13%, Si: less than or equal to 0.12 percent, manganese Mn: 0.40 to 0.50%, phosphorus P: less than or equal to 0.010 percent, sulfur S: less than or equal to 0.005 percent, chromium Cr: 10.20 to 10.80%, molybdenum Mo: 1.00-1.10%, Ni: 0.70-0.80%, Cu: less than or equal to 0.15 percent, vanadium V: 0.15 to 0.25%, Nb: 0.04-0.06%, N: 0.045-0.060%, B: 0.0010-0.0060%, tungsten W: 0.95-1.05%, aluminum Al: less than or equal to 0.010 percent, and the balance of Fe, wherein the sum of the percentages of the elements is 100 percent.
- 3. The heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 as claimed in claim 1, wherein: the subsequent processing treatment comprises rough machining, quenching, tempering, sampling, sample processing, tensile test and Charpy impact test, test report and technical analysis.
- 4. The heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 as claimed in claim 1, wherein when two heat treatment normalizing high-temperature furnaces are used for heat treatment process, the specific process flow is as follows:1, preheating: keeping the temperature at 650 ℃ for 2-3 h; heating to 790 ℃, and preserving heat for 10-12h to ensure thorough burning of the workpiece;2, carrying out high-temperature normalizing by a first heat treatment normalizing high-temperature furnace: heating the furnace to 1080-1110 ℃ in advance, preserving heat for at least 2.5 hours at the temperature, then transferring the preheated and completely burnt workpiece into the furnace, rapidly heating up at the maximum power, passing the workpiece through an alpha + gamma two-phase region at the heating speed as fast as possible, then heating to 1080-1110 ℃ and preserving heat for 6-8 hours, and cooling in the furnace or air; adjusting the temperature between 1080-1110 ℃ to select the most appropriate austenitizing temperature;3, high-temperature tempering: keeping the temperature at 700 ℃ for 15-20h, and cooling in air;4, preheating: keeping the temperature at 650 ℃ for 2-3 h; heating to 790 ℃, and preserving the temperature for 10-12h, wherein thorough burning is guaranteed;and 5, carrying out conventional normalizing by a second heat treatment normalizing high-temperature furnace: heating the furnace to 950-fold-plus-minus 1000 ℃ in advance, preserving heat for at least 2.5h at the temperature, then transferring the preheated and completely-burnt workpiece into the furnace, rapidly heating the workpiece to 950-fold-plus-minus 1000 ℃ by the maximum power, preserving heat for 6-8h by rapidly passing through an alpha + gamma double-phase region, and cooling the furnace or air; adjusting the temperature between 950 and 1000 to obtain the most appropriate austenitizing temperature;6, high-temperature tempering: keeping the temperature at 700 ℃ for 12-15h, and cooling in air.
- 5. The heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 as claimed in claim 4, wherein: when two heat treatment normalizing high-temperature furnaces are adopted for carrying out the heat treatment process, enough other workpieces are reserved in each heat treatment normalizing high-temperature furnace, and the workpieces are in a through-burning state at the corresponding furnace temperature.
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