CN115181900A

CN115181900A - Austenite age hardening heat-resistant steel and preparation method thereof

Info

Publication number: CN115181900A
Application number: CN202210338615.XA
Authority: CN
Inventors: 王晓岚; 倪刚; 邹饰宏; 朱军; 唐家辉
Original assignee: Chengdu Chenglin Cnc Tool Co ltd
Current assignee: Chengdu Chenglin Cnc Tool Co ltd
Priority date: 2022-04-01
Filing date: 2022-04-01
Publication date: 2022-10-14

Abstract

The invention provides austenite aging hardening heat-resistant steel, which comprises the following components: 0.48 to 0.55 weight percent of C, 0.10 to 0.40 weight percent of Si, 6 to 8 weight percent of Mn, 8.5 to 11.5 weight percent of Cr, 6.5 to 8.5 weight percent of Ni, 2.0 to 3.0 weight percent of Mo, 1.2 to 1.8 weight percent of V, 1.27 to 1.6 weight percent of Al, 2.2 to 2.5 weight percent of Cu, 0.02 weight percent of P, 0.004 weight percent of S, and the balance of Fe and impurities. The hardness of the heat-resistant steel product obtained by smelting in a vacuum induction furnace, electroslag remelting, degassing remelting in a vacuum consumable furnace, forging or rolling forming, solid solution and aging heat treatment can reach 37-44 HRC, and the use requirement of a high-corrosion and high-temperature working environment is met.

Description

Austenite age hardening heat-resistant steel and preparation method thereof

Technical Field

The invention belongs to the technical field of heat-resistant material processing, and particularly relates to austenite aging hardening type heat-resistant steel and a preparation method thereof.

Background

The service temperature of the common hot-working die steel is not more than 600 ℃, the corrosion resistance is poor, and the common hot-working die steel cannot stably and continuously work in an environment with the temperature of more than 600 ℃. The austenitic stainless steel is a stainless steel with an austenitic structure at normal temperature, an austenitic phase region is gradually opened by adding alloy elements such as Cr, ni and the like, and the austenitic stainless steel is cooled to normal temperature after being completely austenitized in the heat treatment process, so that the complete austenitic structure can still be obtained.

At present, the conventional types of main austenitic stainless steel are stainless steel of 200 and 300 series, the most common types of the stainless steel are 304/304L, 316 and the like, the stainless steel is mainly characterized in that the content of C is low and is generally not more than 0.1%, cr and Ni elements are greatly increased, the addition amount of the Cr elements is generally more than 13%, the addition amount of the Ni elements is more than 8%, the main corrosion resistance principle of the austenitic stainless steel is a passive film formed on the surface, the corrosion of an external medium to the material can be effectively prevented, but the possible failure mode of the austenitic stainless steel is intergranular corrosion, the intergranular corrosion is mainly caused by that the stainless steel is heated to 450-800 ℃, the Cr elements and the C elements near a grain boundary are easy to form carbides to cause elements near the grain boundary to be scarce, and further cause preferential corrosion of the grain boundary.

Therefore, the development of a heat-resistant steel with better performance becomes a hot spot of research in the field.

Disclosure of Invention

In view of the above, an object of the present invention is to provide an austenitic age-hardening heat-resistant steel having high hardness and capable of effectively suppressing intergranular corrosion, and a method for producing the same.

The invention provides austenitic aging hardening type heat-resistant steel which comprises the following components:

P<0.02wt％，

S<0.004wt％，

the balance being Fe and impurities.

Preferably, the components are as follows:

P<0.02wt％，

S<0.004wt％，

the balance being Fe and impurities.

The invention provides a preparation method of austenitic age hardening type heat-resistant steel in the technical scheme, which comprises the following steps:

the alloy raw materials are smelted and then formed, and then solid solution treatment and aging strengthening are carried out to obtain the austenite aging hardening heat-resistant steel.

Preferably, the smelting method comprises the following steps:

and carrying out one or more of vacuum induction smelting, electroslag remelting and vacuum consumable remelting on the alloy raw material.

Preferably, the molding method comprises: forging and/or rolling.

Preferably, the heating temperature of the forging is 1150-1230 ℃;

the forging temperature is 1100-1200 ℃;

the final forging temperature is more than 800 ℃.

Preferably, the solution treatment method comprises:

and heating, warming, preserving heat and cooling the formed product.

Preferably, the heating temperature is 650-750 ℃; the temperature of the temperature rise is 1100-1200 ℃; the heat preservation time is 2 to 5 hours; the cooling temperature is 50-100 ℃; the cooling method is oil cooling.

Preferably, the aging strengthening method comprises the following steps:

and heating, preserving heat and cooling the product after the solution treatment.

Preferably, the temperature is increased to 600-700 ℃, the heat preservation time is 5-10 hours, and the cooling method is air cooling.

Because the austenite structure has good corrosion resistance, and a certain content of C is dissolved in the matrix in a solid solution manner to strengthen the matrix, the austenite heat-resistant and corrosion-resistant stainless steel containing about 5 percent of C has wide market application prospect. The content of the material C is controlled to be about 5 percent, and the main purpose is to increase the heat resistance of the material so as to meet the requirements that the material cannot generate intergranular corrosion and softening in a 600 ℃ use environment, and simultaneously keep certain corrosion resistance, thereby conforming to the basic working characteristics of austenitic stainless steel. On one hand, the basic characteristics of the austenitic stainless steel are considered in the component design, so that the addition amount of Cr and Ni elements is kept to be in accordance with the general content of the austenitic stainless steel, meanwhile, mo is added to increase the tempering softening resistance of the material, cu, al and the like are increased, and the Al element mainly plays a role in refining the crystal grains of the steel and improving the heat resistance of the steel to a certain degree.

Drawings

FIG. 1 is a high magnification structural view of a heat-resistant steel produced in example 1 of the present invention;

FIG. 2 is a high power structure diagram of a heat resistant steel produced in example 2 of the present invention;

FIG. 3 is a high power structure diagram of a heat resistant steel produced in example 3 of the present invention;

fig. 4 is a thermal expansion curve of heat-resistant steels prepared in examples 1 to 3 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

P<0.02wt％，

S<0.004wt％，

the balance being Fe and impurities.

In the present invention, the mass content of C is preferably 0.48 to 0.52%, more preferably 0.50%; carbon is one of the most important elements for improving the hardenability and the hardenability of the material, and can form alloy carbide to improve the wear resistance, but the material toughness is low when the addition amount is too large, and the material is easy to crack during heat treatment, so the content of C is controlled to be 0.45-55 wt% in the invention.

In the present invention, the Si content is preferably 0.2 to 0.3% by mass, more preferably 0.25% by mass; the silicon is dissolved into the matrix to play a role in solid solution strengthening, so that the strength and the tempering stability of the steel are improved; when the addition amount of silicon is too much, segregation is easy to generate and the brittleness is increased, and the content of silicon is controlled to be 0.10-0.40 wt% in the invention.

In the present invention, the Mn content is preferably 6.5 to 7.5% by mass, more preferably 7%; manganese can improve the hardenability of steel and is an austenite stabilizing element, but the addition of manganese in an excessive amount can cause excessive retained austenite in a quenched structure and possibly reduce the wear resistance of the steel, and the manganese content is controlled to be 6.0-8.0 wt%.

In the present invention, the mass content of Cr is preferably 9 to 11%, more preferably 9.5 to 10.5%, most preferably 10%; chromium can improve the hardenability of the alloy, and the wear resistance can be improved by forming carbide after the chromium is combined with carbon element, but the eutectic carbide is increased and the brittleness is increased due to the excessively high chromium content, and the addition amount of the Cr is controlled to be 8.5-11.5 wt%.

In the present invention, the Ni content is preferably 7 to 8% by mass, and more preferably 7.5% by mass.

In the present invention, the mass content of Mo is preferably 2.3 to 2.7%, more preferably 2.5%; the molybdenum can improve the tempering resistance of the steel, and the molybdenum is combined with carbon to form fine carbide to improve the wear resistance, the excessively high molybdenum content causes the toughness of the material to be reduced and the cost to be increased, and the molybdenum content is controlled to be 2.0 to 3.0wt percent.

In the present invention, the mass content of V is preferably 1.3 to 1.7%, more preferably 1.4 to 1.6%, most preferably 1.5%; the vanadium has great affinity with carbon and nitrogen, the vanadium element and the formed vanadium carbide can pin crystal boundaries and refine crystal grains, and the vanadium carbide is dispersed and stable in property and plays a remarkable role in precipitation strengthening; the generation of eutectic vanadium carbide can be caused by the over-high vanadium content, the hardness is high, and the cracking phenomenon occurs when the matrix is cracked and forged or used; in the invention, the vanadium content is controlled to be 1.2-1.8 wt%.

In the present invention, the Al content is preferably 1.4 to 1.5% by mass, more preferably 1.45% by mass; the addition of a certain amount of Al element mainly forms fine and uniform oxide, can inhibit the growth of crystal grains, and can effectively improve the heat resistance of the material.

In the present invention, the mass content of Cu is preferably 2.3 to 2.4%, more preferably 2.35%; cu can obviously increase the atmospheric corrosion resistance of the material, and 2-3 wt% of copper is added into austenitic stainless steel, so that the corrosion resistance of the austenitic stainless steel in an acidic medium can be improved.

In the present invention, the sulfur is a harmful element to lower the toughness of the steel and cause anisotropy, and in the present invention, the sulfur is preferably controlled to 0.003wt% or less; the phosphorus is a harmful element, improves the brittleness of steel, deteriorates welding performance and increases temper brittleness, and the phosphorus content is preferably controlled to be less than 0.02wt% in the invention.

In the present invention, the austenitic age-hardening heat-resistant steel preferably contains: 0.49 to 0.53 weight percent of C, 0.28 to 0.30 weight percent of Si, 6.8 to 7.1 weight percent of Mn, 9.31 to 10.0 weight percent of Cr, 6.8 to 7.65 weight percent of Ni, 2.35 to 2.55 weight percent of Mo, 1.5 to 1.6 weight percent of V, 1.35 to 1.55 weight percent of Al, 2.12 to 2.16 weight percent of Cu, 0.02 weight percent of P, 0.004 weight percent of S, and the balance of Fe and impurities.

In the present invention, the austenitic age-hardening heat-resistant steel composition is more preferably: 0.49wt% of C, 0.28wt% of Si, 7.1wt% of Mn, 9.5wt% of Cr, 6.8wt% of Ni, 2.5wt% of Mo, 1.6wt% of V, 1.35wt% of Al, 2.4wt% of Cu, 0.02wt% of P, 0.004wt% of S and the balance of Fe and impurities.

In the present invention, the austenitic age-hardening heat-resistant steel composition is more preferably: 0.52wt% of C, 0.3wt% of Si, 6.8wt% of Mn, 9.31wt% of Cr, 7.25wt% of Ni, 2.35wt% of Mo, 1.50wt% of V, 1.45wt% of Al, 2.5wt% of Cu, 0.02wt% of P, 0.004wt% of S and the balance of Fe and impurities.

In the present invention, the austenitic age-hardening heat-resistant steel composition is more preferably: 0.53wt% of C, 0.3wt% of Si, 6.9wt% of Mn, 10.0wt% of Cr, 7.65wt% of Ni, 2.55wt% of Mo, 1.6wt% of V, 1.55wt% of Al, 2.3wt% of Cu, 0.02wt% of P, 0.004wt% of S and the balance of Fe and impurities.

The austenite age-hardening stainless steel provided by the invention has the hardness of 37-44 HRC, can effectively inhibit intergranular corrosion, stably works at the temperature of above 600 ℃, and has obviously improved tempering stability.

the alloy raw material is smelted and then molded, and then solid solution treatment and aging strengthening are carried out to obtain the austenite aging hardening type heat-resistant steel.

The austenitic age hardening heat-resistant steel provided by the invention has high use hardness and excellent corrosion resistance after solid solution aging, and the use hardness is 37-44 HRC after solid solution aging, and the austenitic age hardening heat-resistant steel has excellent corrosion resistance.

In the present invention, the method for smelting preferably includes:

In the invention, the ingredients of the vacuum induction smelting process preferably comprise:

P<0.02wt％，

S<0.004wt％，

the balance being Fe and impurities.

In the present invention, the vacuum induction smelting is preferably performed in a vacuum induction furnace; p is preferably controlled to be less than 0.02wt% during tapping in the vacuum induction smelting process, and S is controlled to be less than 0.006wt% through raw material components.

In the present invention, the vacuum induction smelting is preferably performed in a vacuum induction furnace; preferably, pure iron and alloy lump materials are added according to the proportion of steel components, when the vacuum degree reaches 0.69Pa through vacuumizing, the materials are heated by induction to be melted at the temperature of not less than 1550 ℃, molten steel splashing and alloy volatilization are prevented in the process, sampling and analysis are carried out in stages in the process, the alloy is supplemented properly until the alloy reaches the standard, casting is started, and a heat-insulating cap is adopted to carry out vacuum cooling.

In the invention, the electroslag remelting is preferably atmosphere protection electroslag remelting, and the steel ingot obtained by vacuum induction smelting is preferably subjected to atmosphere protection electroslag remelting to improve the cleanliness of steel, so that the S content is reduced to less than 0.004wt%; the solidification condition of the steel is improved by controlling the smelting preparation, thereby reducing the element segregation, reducing the defects of loosening, shrinkage cavity and the like, and improving the compactness of the cast ingot.

In the present invention, the electroslag remelting is preferably gas-shielded electroslag; preferably, a steel ingot to be remelted is connected with the dummy electrode and is arranged on the electroslag conducting arm, the remelting slag system is a ternary slag system or a quaternary slag system, and about 40kg (drying at 750 ℃) of a ton of steel is used; after the equipment is sealed, argon is introduced for 30 minutes, remelting is started, and the melting speed is controlled within 60 kg/minute; and after remelting is finished, demolding and air-cooling to room temperature.

In the invention, the remelting slag is preferably a ternary slag system, and preferably comprises:

calcium oxide, aluminum oxide and calcium fluoride.

In the invention, the mass content of the calcium oxide in the ternary slag system is preferably 15-25%, more preferably 18-22%, and most preferably 20%; the mass content of the alumina in the ternary slag system is preferably 15-25%, more preferably 18-22%, and most preferably 20%; the mass content of the calcium fluoride in the ternary slag system is preferably 55 to 65%, more preferably 58 to 62%, and most preferably 60%.

In the present invention, the vacuum consumable remelting is preferably vacuum consumable degassing remelting, preferably performed in a vacuum consumable furnace. The invention carries out vacuum consumable treatment on the steel ingot after electroslag remelting, can obviously reduce the gas content in the steel, and improves the ingot structure again, so that the content of O and N in the steel is reduced to 0.003wt% or lower.

In the present invention, the vacuum consumable remelting is preferably performed in a vacuum consumable furnace; preferably, connecting a steel ingot to be remelted with a false electrode, installing the steel ingot on equipment, vacuumizing the equipment after the equipment is sealed, and remelting the steel ingot, wherein the melting speed is controlled within 50 kg/min; and after remelting is finished, demolding and air-cooling to room temperature.

In the invention, the smelting method can also be direct die casting after vacuum induction smelting.

In the present invention, the method of forming preferably comprises forging and/or rolling.

In the invention, the heating temperature in the forging process is preferably 1150-1230 ℃, more preferably 1160-1220 ℃, more preferably 1170-1210 ℃, more preferably 1180-1200 ℃, and most preferably 1190 ℃; the forging temperature in the forging process is preferably 1100-1200 ℃, more preferably 1130-1170 ℃, and most preferably 1150 ℃; the finish forging temperature during the forging process is preferably > 800 ℃, more preferably 820 to 920 ℃, more preferably 850 to 900 ℃, and most preferably 860 to 880 ℃.

In the invention, after the material is heated to 1220 ℃ preferably in the forging process, the material is discharged from a furnace for forging and cogging, a round section is forged into a square section, the sectional area is gradually reduced, the length of the material is increased, the material is placed into the furnace for reheating when the temperature of the material is lower than 920 ℃, and finally, forming and forging are carried out by the last fire; and cooling the forging steel to room temperature.

In the present invention, the initial rolling temperature in the rolling process is preferably 1100 to 1200 ℃, more preferably 1130 to 1170 ℃, and most preferably 1150 ℃.

In the invention, after the rolling process is preferably heated to 1150 ℃, the round section is taken out of a furnace for rolling, the round section is firstly rolled into a square section, the sectional area is reduced step by step, and the length of the material is increased; and cooling the water to room temperature until the specification requirement is met.

In the present invention, the shaped bar or plate is preferable.

In the present invention, the method of solution treatment preferably includes:

and heating, warming, preserving heat and cooling the formed product.

In the present invention, the solution treatment is preferably performed in a heating furnace; the heating temperature in the solution treatment process is preferably 650 to 750 ℃, more preferably 680 to 720 ℃, and most preferably 700 ℃; the temperature rise is preferably 1100 to 1200 ℃, more preferably 1130 to 1170 ℃, and most preferably 1150 ℃; the holding time is preferably 2 to 5 hours, more preferably 3 to 4 hours, and most preferably 3.5 hours; the cooling temperature is preferably 50 to 100 ℃, more preferably 60 to 90 ℃, and most preferably 70 to 80 ℃; the cooling method is preferably oil cooling, which enables rapid cooling.

In the present invention, it is preferable to obtain a supersaturated solid solution by sufficiently dissolving the excess phase back into the matrix by solution treatment, and to reduce the hardness of the material so as to satisfy the machining requirements.

In the present invention, the aging strengthening method preferably includes:

In the invention, the temperature rise temperature in the aging strengthening process is preferably 600-700 ℃, more preferably 630-670 ℃, and most preferably 650 ℃; the heat preservation time is preferably 5 to 10 hours, more preferably 6 to 9 hours, and most preferably 7 to 8 hours; the cooling method is preferably tapping air cooling.

In the present invention, it is preferable to obtain a material having a hardness of 37 to 44HRC by aging hardening.

The hardness of the material can reach 37-44 HRC after solid solution and aging heat treatment by smelting in a vacuum induction furnace, electroslag remelting, degassing remelting in a vacuum consumable furnace, forging or rolling forming, and meeting the use requirements of high-corrosion and high-temperature working environments. The method provided by the invention can be used for obtaining the austenitic stainless steel material with pure matrix, low gas content and high corrosion resistance, the hardness after solid solution is less than or equal to 225HRC, cold processing can be carried out, the hardness after aging heat treatment is 37-44 HRC, and the method has better effect on working condition environment under high corrosion and high use hardness.

Example 1

The alloy raw material is prepared by adopting vacuum induction melting, atmosphere protection electroslag remelting and forging forming processes; after electroslag remelting, the diameter of the steel ingot is phi 110 mm, and the weight of the steel ingot is 96 kg; the specification of the forged finished product is a bar with the diameter of phi 50 mm;

adding pure iron and alloy lump materials according to the proportion of steel components in the vacuum induction smelting process, starting induction heating when the vacuum degree reaches 0.69Pa by vacuumizing to melt the materials at the temperature of not less than 1550 ℃, preventing molten steel from splashing and alloy volatilization in the process, sampling and analyzing in stages in the process, appropriately supplementing the alloy until the alloy reaches the standard, starting casting, and cooling in vacuum by adopting a heat-insulating cap;

in the electroslag remelting process, a steel ingot to be remelted is connected with a dummy electrode and is arranged on an electroslag conducting arm, a remelting slag system is a ternary slag system (20% of calcium oxide, 20% of aluminum oxide and 60% of calcium fluoride), and about 40kg (dried at 750 ℃) of ton steel is used; after the equipment is sealed, argon is introduced for 30 minutes, remelting is started, and the melting speed is controlled to be 55-60 kg/minute; after remelting is finished, demolding, and air-cooling to room temperature;

heating to 1220 ℃ in the forging process, discharging from a furnace, forging and cogging, forging a round section into a square section, gradually reducing the sectional area, increasing the length of the material, entering the furnace to reheat when the temperature of the material is lower than 920 ℃, finally performing final forming forging by using fire, and cooling to room temperature by water after the forging is finished.

Quenching in a vacuum oil furnace, tempering in a pit furnace for solution treatment and aging strengthening, wherein the quenching in the vacuum oil furnace comprises heating, temperature rising, heat preservation and cooling, the heating temperature is 700 ℃, the temperature rising is 1150 ℃, the heat preservation time is 3.5 hours, and the cooling method is oil cooling; the well furnace tempering method comprises the steps of heating, heat preservation and cooling, wherein the heating temperature is 650 ℃, the heat preservation time is 7 hours, and the cooling method is air cooling.

According to the method specified in national standard GBT-11170-2008 & methods for atomic emission spectrometry (conventional method) of stainless steel spark sources, the heat-resistant steel prepared in the embodiment 1 of the invention is subjected to component detection, and the detection results are as follows:

C	Si	Mn	P	S	Cr	Mo	V	Ni	Cu	Al	allowance of
												0.487	0.35	6.397	0.0079	<0.003	8.714	2.203	1.455	7.368	2.4	1.272	Fe

Example 2

The alloy raw material is prepared by adopting the processes of vacuum induction melting, vacuum consumable remelting, forging cogging and roll forming; after vacuum consumable remelting, the diameter of the steel ingot is 150 mm, and the weight is 203 kg; the specification of the forged finished product is a bar with the diameter of phi 50 mm;

adding pure iron and alloy lump materials according to the proportion of steel components in the vacuum induction smelting process, starting to perform induction heating on the materials when the vacuum degree reaches 0.69Pa by vacuumizing to melt the materials at the temperature of not less than 1550 ℃, preventing molten steel from splashing and alloy volatilization in the process, sampling and analyzing in stages in the process, appropriately supplementing the alloy until the alloy reaches the standard, starting to cast, and cooling in vacuum by adopting a heat-insulating cap;

in the vacuum consumable remelting process, connecting a steel ingot to be remelted with a false electrode, installing the steel ingot on equipment, vacuumizing the equipment after the equipment is sealed, remelting the steel ingot, controlling the melting speed to be 45-50 kg/min, demoulding and air-cooling the steel ingot to room temperature after remelting is finished;

heating to 1220 ℃ in the forging process, discharging from a furnace, forging and cogging, forging a round section into a square section, gradually reducing the sectional area, increasing the length of the material, entering the furnace for reheating when the temperature of the material is lower than 920 ℃, finally performing final forming forging by using fire, and cooling to room temperature by water after the forging is finished;

heating to 1150 ℃ in the rolling process, discharging from a furnace for rolling, rolling a circular section into a square section, reducing the sectional area one by one, increasing the length of the material until the material reaches the specification requirement, and cooling to room temperature by water.

Quenching by adopting a vacuum gas furnace, and tempering by adopting a box furnace to perform solution treatment and aging strengthening; the vacuum gas furnace quenching comprises heating, heat preservation and cooling, wherein the heating temperature is 650 ℃, the heating temperature is up to 1150 ℃, the heat preservation time is 4 hours, and the cooling method is oil cooling; the box-type furnace tempering method comprises the steps of heating, heat preservation and cooling, wherein the heating temperature is 700 ℃, the heat preservation time is 7.5 hours, and the cooling method is air cooling.

The heat-resistant steel prepared in example 2 of the present invention was subjected to composition measurement in accordance with the method of example 1, and the measurement results were as follows:

C	Si	Mn	P	S	Cr	Mo	V	Ni	Cu	Al	balance of
												0.490	0.4	6.392	0.01	<0.003	8.73	2.198	1.454	7.392	2.5	1.286	Fe

Example 3

Preparing alloy raw materials by adopting a vacuum induction melting and rolling forming process; carrying out vacuum induction melting to obtain a steel ingot with the diameter of phi 80 mm and the weight of 510 kg; the specification of the forged finished product is a bar stock with the diameter of phi 30 mm;

Quenching by adopting a vacuum gas furnace, and tempering by adopting a box furnace to perform solution treatment and aging strengthening; the vacuum gas furnace quenching comprises heating, temperature rising, heat preservation and cooling, wherein the heating temperature is 700 ℃, the temperature rising temperature is up to 1160 ℃, the heat preservation time is 3 hours, and the cooling method is oil cooling; the box-type furnace tempering method comprises the steps of heating, heat preservation and cooling, wherein the heating temperature is 660 ℃, the heat preservation time is 8 hours, and the cooling method is air cooling.

The heat-resistant steel prepared in example 3 of the present invention was subjected to composition measurement in accordance with the method of example 1, and the measurement results were as follows:

C	Si	Mn	P	S	Cr	Mo	V	Ni	Cu	Al	allowance of
												0.484	0.4	6.352	0.0078	<0.003	8.727	2.183	1.7	7.316	2.3	1.3	Fe

Performance detection

GB T228.1-2010 metal material tensile test, GBT _232-2010 metal material room temperature bending test and GBT230.1-2004 metal Rockwell hardness test are adopted to test the heat-resistant steels with different hardness prepared in the examples, and the tensile strength and the yield strength are as follows:

FIGS. 1 to 3 are metallographic images of products prepared in examples 1 to 3 of the present invention, and it can be seen that the material contains uniformly distributed carbides and matrix.

Fig. 4 is a thermal expansion curve of the heat-resistant steel prepared in examples 1 to 3 of the present invention, which is measured by GB/T4339-2008 "determination of thermal expansion characteristic parameters of metal material", and it can be seen that the material expansion amount increases linearly with the increase of temperature, and a higher thermal expansion rate is an important characteristic of the heat-resistant steel.

The method provided by the invention can not only ensure that the austenitic stainless steel accords with the conventional service performance and has good corrosion resistance, but also ensure that the material has excellent heat resistance and effectively avoids intergranular corrosion; the hardness of the material after solid solution and aging treatment can reach 37-44 HRC, and the material has more excellent heat resistance and corrosion resistance.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

While the invention has been described and illustrated with reference to specific embodiments thereof, such description and illustration are not intended to limit the invention. It will be clearly understood by those skilled in the art that various changes may be made to adapt a particular situation, material, composition of matter, substance, method or process to the objective, spirit and scope of this application without departing from the true spirit and scope of the invention as defined by the appended claims. All such modifications are intended to be within the scope of the claims appended hereto. Although the methods disclosed herein have been described with reference to particular operations performed in a particular order, it should be understood that these operations may be combined, sub-divided, or reordered to form equivalent methods without departing from the teachings of the present disclosure. Accordingly, unless specifically indicated herein, the order and grouping of the operations is not a limitation of the present application.

Claims

1. An austenitic age-hardening heat-resistant steel comprises the following components:

P<0.02wt％，

S<0.004wt％，

the balance being Fe and impurities.

2. The austenitic age-hardening heat-resistant steel of claim 1, comprising the following components:

P<0.02wt％，

S<0.004wt％，

the balance being Fe and impurities.

3. A method of producing the austenitic age-hardening heat-resistant steel of claim 1, comprising:

4. The method of claim 3, wherein the method of smelting comprises:

5. The method of claim 3, wherein the method of forming comprises: forging and/or rolling.

6. The method of claim 5, wherein the forging is performed at a heating temperature of 1150 to 1230 ℃;

the forging temperature is 1100-1200 ℃;

the final forging temperature is more than 800 ℃.

7. The method of claim 3, wherein the method of solution treatment comprises:

and heating, warming, preserving heat and cooling the formed product.

8. The method of claim 7, wherein the heating temperature is 650 to 750 ℃; the temperature of the temperature rise is 1100-1200 ℃; the heat preservation time is 2 to 5 hours; the cooling temperature is 50-100 ℃; the cooling method is oil cooling.

9. The method of claim 3, wherein the method of aging strengthening comprises:

10. The method according to claim 9, wherein the temperature is raised to 600-700 ℃, the holding time is 5-10 hours, and the cooling method is air cooling.