阅读说明：本技术 一种低合金超高强度钢的制造方法 (Manufacturing method of low-alloy ultrahigh-strength steel ) 是由 孙海涛 栾吉哲 钟庆元 刘军凯 冯文静 于 2021-04-28 设计创作，主要内容包括：本发明公开了一种低合金超高强度钢,该低合金超高强度钢的配方包括以下组份：C：0.30-0.35%、Mn：1.0-1.5%、Si：1.50-1.80%、S≤0.010%、P≤0.010%、Ni：1.45-1.85%、Al：0.03-0.08%、Cr：0.80-1.20%、V:0.08-0.15%、H：≤0.0001%、O：≤0.0015%、N：≤0.010%、余量为Fe和其它不可避免的杂质,本发明还公开了一种低合金超高强度钢的制造方法,该制备方法包括以下步骤：定量称取,冶炼,锻造,正火,一次回火,淬火,二次回火；本发明提出的低合金超高强度钢与现有30CrMnSiNi2相比较,优化冶炼工艺,调整为真空感应+真空自耗的冶炼方法,钢锭在热加工前使用高温扩散工艺,可以减少使碳化物弥散分布,通过对化学成分的调整和冶炼方法的改变,提高其纯度,细化组织,晶粒更细使其强度及韧性、塑性均得到提高。(The invention discloses low-alloy ultrahigh-strength steel, which comprises the following components in parts by weight: c: 0.30-0.35%, Mn: 1.0-1.5%, Si: 1.50-1.80%, S is less than or equal to 0.010%, P is less than or equal to 0.010%, Ni: 1.45-1.85%, Al: 0.03-0.08%, Cr: 0.80-1.20%, V0.08-0.15%, H: less than or equal to 0.0001%, O: less than or equal to 0.0015 percent, N: the invention also discloses a manufacturing method of the low-alloy ultrahigh-strength steel, which comprises the following steps: quantitative weighing, smelting, forging, normalizing, primary tempering, quenching and secondary tempering; compared with the existing 30CrMnSiNi2, the low-alloy ultrahigh-strength steel provided by the invention has the advantages that the smelting process is optimized and adjusted to a vacuum induction and vacuum self-consumption smelting method, the high-temperature diffusion process is used before hot processing of steel ingots, so that the dispersion distribution of carbides can be reduced, the purity of the steel ingots is improved by adjusting chemical components and changing the smelting method, the structure is refined, and the strength, the toughness and the plasticity of the steel ingots are improved by making grains finer.)

1. A low-alloy ultrahigh-strength steel, which is characterized in that; the formula of the low-alloy ultrahigh-strength steel comprises the following components: c: 0.30-0.35%, Mn: 1.0-1.5%, Si: 1.50-1.80%, S is less than or equal to 0.010%, P is less than or equal to 0.010%, Ni: 1.45-1.85%, Al: 0.03-0.08%, Cr: 0.80-1.20%, V0.08-0.15%, H: less than or equal to 0.0001%, O: less than or equal to 0.0015 percent, N: less than or equal to 0.010 percent, and the balance of Fe and other inevitable impurities.

2. A low alloy ultra high strength steel as claimed in claim 1, wherein: the method comprises the following steps: 0.30%, Mn: 1.0%, Si: 1.50%, S: 0.010%, P: 0.010%, Ni: 1.45%, Al: 0.03%, Cr: 0.80%, V:0.08%, H: 0.0001%, O: 0.0015%, N: 0.010% and the balance of Fe and other inevitable impurities.

3. A low alloy ultra high strength steel as claimed in claim 1, wherein: the method comprises the following steps: 0.35%, Mn: 1.5%, Si: 1.80%, S: 0.08%, P: 0.09%, Ni: 1.85%, Al: 0.08%, Cr: 1.20%, V: 0.15, H: 0.00008%, O: 0.0014%, N: 0.009%, and the balance Fe and other inevitable impurities.

4. A low alloy ultra high strength steel as claimed in claim 1, wherein: the method comprises the following steps: 0.32%, Mn: 1.2%, Si: 1.60%, S0.007%, P0.006%, Ni: 1.55%, Al: 0.05%, Cr: 0.90%, V:0.10%, H: 0.00007%, O: 0.0013%, N: 0.007% and the balance of Fe and other inevitable impurities.

5. A low alloy ultra high strength steel as claimed in claim 1, wherein: the method comprises the following steps: 0.34%, Mn: 1.4%, Si: 1.70%, S0.004%, P0.005%, Ni: 1.65%, Al: 0.06%, Cr: 1.10%, V:0.13%, H: 0.00004%, O: 0.0011%, N: 0.004%, and the balance of Fe and other inevitable impurities.

6. A method of manufacturing a low alloy ultra high strength steel as claimed in any one of claims 1 to 5, wherein: the preparation method comprises the following steps:

s1: quantitative weighing, namely weighing all the raw materials according to the components;

s2: smelting, namely smelting the raw materials into steel ingots by adopting a smelting process of smelting and casting in a vacuum induction furnace and vacuum consumable remelting;

s3: forging, namely heating the consumable steel ingot to 1220 ℃, preserving the heat for more than 25h, diffusing to disperse and distribute carbide, discharging from a furnace and forging after diffusion, wherein the open forging temperature is 1180-1200 ℃, the finish forging temperature is 850-900 ℃, and the steel can be guaranteed to be formed in the optimal thermoplastic zone in the temperature range, so that forging cracking is avoided;

s4: normalizing at 920 deg.C, keeping the temperature at 2.5 mm/min +60min, and air cooling;

s5: tempering for the first time, treating the tempering at 680 ℃, preserving heat according to 2.5 mm/min and 120-240 min, and cooling in air;

s6: quenching, treating at 900 deg.C, keeping the temperature at 2.5 mm/min +60min, and oil cooling;

s7: and (4) secondary tempering, wherein the tempering is carried out according to salt bath treatment at 260 ℃, heat preservation is carried out according to the ratio of 2.5 mm/min to 60min, and air cooling is carried out.

7. A low alloy ultra high strength steel casting mold according to claim 6, comprising a bottom plate (1), characterized in that: the top surface of chassis (1) is provided with the ingot mould of falling (2), the top of falling ingot mould (2) is provided with the ingot top mould (3), outer loop splice groove (4) have been seted up to the top surface of falling ingot mould (2), inner ring splice groove (5) have been seted up to the bottom surface of falling ingot top mould (3), the interior anchor ring of falling ingot top mould (3) has been seted up and has been accomodate groove (6), the inside of accomodating groove (6) is provided with splint (7), the outer anchor ring of falling ingot top mould (3) is provided with mounting bracket (9), the inside of mounting bracket (9) is provided with miniature telescopic link (8), the piston rod of miniature telescopic link (8) runs through the surface of falling ingot top mould (3) after-fixing at splint (7), the top surface of chassis (1) is provided with electric hydraulic cylinder (10), the piston rod of electric hydraulic cylinder (10) is fixed in the bottom surface of connecting plate (11), the outer anchor ring at falling ingot top mould (3) is fixed in connecting plate (11).

Technical Field

The invention relates to the technical field of low-alloy ultrahigh-strength steel preparation, in particular to a method for manufacturing low-alloy ultrahigh-strength steel.

Background

The ultra-high strength steel has tensile strength of more than 1400MPa at room temperature and yield strength of more than 1300 MPa. The ultra-high strength steel not only requires the tensile strength of more than 1400MPa, but also has certain plasticity and toughness, as small as possible notch sensitivity, high fatigue strength, good public welfare, accordance with resource conditions, low price and the like. A variety of low alloy ultra high strength steels have therefore been developed. The method is widely applied to the fields of aircraft landing parts, bulletproof steel plates and the like, the application range of the method is continuously expanded, and the method has wide development prospect.

At present, low-alloy ultrahigh-strength steel is developed on the basis of quenched and tempered structural steel, and a small amount of various alloy elements are added into the steel, so that the steel is subjected to solid solution strengthening, and the hardenability and the martensite tempering stability of the steel are improved. The total content of main elements such as Mn, Cr, Si, Ni, Mo, V and the like and alloy elements thereof is generally not more than 5 percent, so that the produced 30CrMnSiNi2 steel has the defects: the chassis 1 has high tensile strength and relatively poor toughness and plasticity; the steel of the inverted ingot bottom die 2 is produced by vacuum induction and electroslag, and the purity is relatively not optimal; the inverted ingot top die 3 has no element for refining grains, and the normalized grain size grade after forging is only 5 grades.

Disclosure of Invention

The present invention is directed to a method for manufacturing a low-alloy ultrahigh-strength steel, which solves the above-mentioned problems of the prior art.

In order to achieve the purpose, the invention provides the following technical scheme: the formula of the low-alloy ultrahigh-strength steel comprises the following components: c: 0.30-0.35%, Mn: 1.0-1.5%, Si: 1.50-1.80%, S is less than or equal to 0.010%, P is less than or equal to 0.010%, Ni: 1.45-1.85%, Al: 0.03-0.08%, Cr: 0.80-1.20%, V0.08-0.15%, H: less than or equal to 0.0001%, O: less than or equal to 0.0015 percent, N: less than or equal to 0.010 percent, and the balance of Fe and other inevitable impurities.

Preferably, the compound comprises C: 0.30%, Mn: 1.0%, Si: 1.50%, S: 0.010%, P: 0.010%, Ni: 1.45%, Al: 0.03%, Cr: 0.80%, V:0.08%, H: 0.0001%, O: 0.0015%, N: 0.010% and the balance of Fe and other inevitable impurities.

Preferably, the compound comprises C: 0.35%, Mn: 1.5%, Si: 1.80%, S: 0.08%, P: 0.09%, Ni: 1.85%, Al: 0.08%, Cr: 1.20%, V: 0.15, H: 0.00008%, O: 0.0014%, N: 0.009%, and the balance Fe and other inevitable impurities.

Preferably, the compound comprises C: 0.32%, Mn: 1.2%, Si: 1.60%, S0.007%, P0.006%, Ni: 1.55%, Al: 0.05%, Cr: 0.90%, V:0.10%, H: 0.00007%, O: 0.0013%, N: 0.007% and the balance of Fe and other inevitable impurities.

Preferably, the compound comprises C: 0.34%, Mn: 1.4%, Si: 1.70%, S0.004%, P0.005%, Ni: 1.65%, Al: 0.06%, Cr: 1.10%, V:0.13%, H: 0.00004%, O: 0.0011%, N: 0.004%, and the balance of Fe and other inevitable impurities.

A method for manufacturing a low alloy ultra high strength steel as described above, comprising the steps of:

s1: quantitative weighing, namely weighing all the raw materials according to the components;

s2: smelting, namely smelting the raw materials into steel ingots by adopting a smelting process of smelting and casting in a vacuum induction furnace and vacuum consumable remelting;

s3: forging, namely heating the consumable steel ingot to 1220 ℃, preserving the heat for more than 25h, diffusing to disperse and distribute carbide, discharging from a furnace and forging after diffusion, wherein the open forging temperature is 1180-1200 ℃, the finish forging temperature is 850-900 ℃, and the steel can be guaranteed to be formed in the optimal thermoplastic zone in the temperature range, so that forging cracking is avoided;

s4: normalizing at 920 deg.C, keeping the temperature at 2.5 mm/min +60min, and air cooling;

s5: tempering for the first time, treating the tempering at 680 ℃, preserving heat according to 2.5 mm/min and 120-240 min, and cooling in air;

s6: quenching, treating at 900 deg.C, keeping the temperature at 2.5 mm/min +60min, and oil cooling;

s7: and (4) secondary tempering, wherein the tempering is carried out according to salt bath treatment at 260 ℃, heat preservation is carried out according to the ratio of 2.5 mm/min to 60min, and air cooling is carried out.

The utility model provides a low-alloy ultrahigh-strength steel casting mold, which comprises a base, the top surface on chassis is provided with the ingot mould of falling, the top of falling the ingot mould is provided with the ingot top mould, the outer loop splice groove has been seted up to the top surface of falling the ingot mould of falling, the inner ring splice groove has been seted up to the bottom surface of falling the ingot top mould, the groove has been seted up to the inner ring face of falling the ingot top mould, the inside of accomodating the groove is provided with splint, the outer anchor ring of falling the ingot top mould is provided with the mounting bracket, the inside of mounting bracket is provided with miniature telescopic link, miniature telescopic link's piston rod runs through the surface of falling ingot top mould after-fixing at splint, the top surface on chassis is provided with electric hydraulic cylinder, electric hydraulic cylinder's piston rod is fixed in the bottom surface of connecting plate, the outer anchor ring at the ingot top mould is fixed to the connecting plate.

Compared with the prior art, the invention has the beneficial effects that:

1. compared with the existing 30CrMnSiNi2, the low-alloy ultrahigh-strength steel provided by the invention has the advantages that the smelting process is optimized and adjusted to a smelting method of vacuum induction and vacuum self-consumption, a high-temperature diffusion process is used before hot processing of a steel ingot, so that the dispersion distribution of carbides can be reduced, the purity of the steel ingot is improved by adjusting chemical components and changing the smelting method, the structure is refined, and the strength, the toughness and the plasticity of the steel ingot are improved by making grains finer;

2. the low-alloy ultrahigh-strength steel casting mold provided by the invention is divided into an inverted ingot bottom mold and an inverted ingot top mold, after the steel ingot is formed, the miniature telescopic rod pushes the clamping plate to clamp the top of the steel ingot, and the electric hydraulic cylinder pushes the connecting plate to drive the inverted ingot top mold to lift, so that the steel ingot is conveniently demoulded.

Drawings

FIG. 1 is a schematic view of the mold structure of the present invention,

Fig. 2 is an enlarged schematic view of a structure in fig. 1.

In the figure: the device comprises a chassis 1, an ingot-pouring bottom die 2, an ingot-pouring top die 3, an outer ring splicing groove 4, an inner ring splicing groove 5, a containing groove 6, a clamping plate 7, a micro telescopic rod 8, an installation frame 9, an electric hydraulic cylinder 10 and a connecting plate 11.

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 derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

The invention provides a technical scheme that: the formula of the low-alloy ultrahigh-strength steel comprises the following components: c: 0.30%, Mn: 1.0%, Si: 1.50%, S: 0.010%, P: 0.010%, Ni: 1.45%, Al: 0.03%, Cr: 0.80%, V:0.08%, H: 0.0001%, O: 0.0015%, N: 0.010% and the balance of Fe and other inevitable impurities.

A method for manufacturing a low alloy ultra high strength steel as described above, comprising the steps of:

s1: quantitative weighing, namely weighing all the raw materials according to the components;

s2: smelting, namely smelting the raw materials into steel ingots by adopting a smelting process of smelting and casting in a vacuum induction furnace and vacuum consumable remelting;

s3: forging, namely heating the consumable steel ingot to 1220 ℃, preserving the heat for more than 25h, diffusing to ensure that carbide is dispersed and distributed, discharging from a furnace and forging after diffusion, wherein the open forging temperature is 1180 ℃, the finish forging temperature is 850 ℃, and the steel can be ensured to be formed in the optimal thermoplastic region within the temperature range, so that forging cracking is avoided;

s4: normalizing at 920 deg.C, keeping the temperature at 2.5 mm/min +60min, and air cooling;

s5: tempering for the first time, treating at 680 ℃, preserving heat at 2.5 mm/min +120min, and cooling in air;

s6: quenching, treating at 900 deg.C, keeping the temperature at 2.5 mm/min +60min, and oil cooling;

s7: and (4) secondary tempering, wherein the tempering is carried out according to salt bath treatment at 260 ℃, heat preservation is carried out according to the ratio of 2.5 mm/min to 60min, and air cooling is carried out.

Example two

The invention provides a technical scheme that: the formula of the low-alloy ultrahigh-strength steel comprises the following components: c: 0.35%, Mn: 1.5%, Si: 1.80%, S: 0.08%, P: 0.09%, Ni: 1.85%, Al: 0.08%, Cr: 1.20%, V: 0.15, H: 0.00008%, O: 0.0014%, N: 0.009%, and the balance Fe and other inevitable impurities.

A method for manufacturing a low alloy ultra high strength steel as described above, comprising the steps of:

s1: quantitative weighing, namely weighing all the raw materials according to the components;

s2: smelting, namely smelting the raw materials into steel ingots by adopting a smelting process of smelting and casting in a vacuum induction furnace and vacuum consumable remelting;

s3: forging, namely heating the consumable steel ingot to 1220 ℃, preserving the heat for more than 25h, diffusing to ensure that carbide is dispersed and distributed, discharging from a furnace and forging after diffusion, wherein the open forging temperature is 1200 ℃, the finish forging temperature is 900 ℃, and the steel can be ensured to be formed in the optimal thermoplastic region within the temperature range, so that the forging cracking is avoided;

s4: normalizing at 920 deg.C, keeping the temperature at 2.5 mm/min +60min, and air cooling;

s5: tempering for the first time, treating at 680 ℃, preserving heat according to 2.5 mm/min +240min, and cooling in air;

s6: quenching, treating at 900 deg.C, keeping the temperature at 2.5 mm/min +60min, and oil cooling;

s7: and (4) secondary tempering, wherein the tempering is carried out according to salt bath treatment at 260 ℃, heat preservation is carried out according to the ratio of 2.5 mm/min to 60min, and air cooling is carried out.

EXAMPLE III

The invention provides a technical scheme that: the formula of the low-alloy ultrahigh-strength steel comprises the following components: c: 0.32%, Mn: 1.2%, Si: 1.60%, S0.007%, P0.006%, Ni: 1.55%, Al: 0.05%, Cr: 0.90%, V:0.10%, H: 0.00007%, O: 0.0013%, N: 0.007% and the balance of Fe and other inevitable impurities.

A method for manufacturing a low alloy ultra high strength steel as described above, comprising the steps of:

s1: quantitative weighing, namely weighing all the raw materials according to the components;

s2: smelting, namely smelting the raw materials into steel ingots by adopting a smelting process of smelting and casting in a vacuum induction furnace and vacuum consumable remelting;

s3: forging, namely heating the consumable steel ingot to 1220 ℃, preserving the heat for more than 25h, diffusing to ensure that carbide is dispersed and distributed, discharging from a furnace and forging after diffusion, wherein the open forging temperature is 1185 ℃, the finish forging temperature is 860 ℃, and the steel can be ensured to be formed in the optimal thermoplastic region within the temperature range, so that forging cracking is avoided;

s4: normalizing at 920 deg.C, keeping the temperature at 2.5 mm/min +60min, and air cooling;

s5: tempering for the first time, treating at 680 ℃, keeping the temperature for 2.5 mm/min +160min, and cooling in air;

s6: quenching, treating at 900 deg.C, keeping the temperature at 2.5 mm/min +60min, and oil cooling;

s7: and (4) secondary tempering, wherein the tempering is carried out according to salt bath treatment at 260 ℃, heat preservation is carried out according to the ratio of 2.5 mm/min to 60min, and air cooling is carried out.

Example four

The invention provides a technical scheme that: the formula of the low-alloy ultrahigh-strength steel comprises the following components: c: 0.34%, Mn: 1.4%, Si: 1.70%, S0.004%, P0.005%, Ni: 1.65%, Al: 0.06%, Cr: 1.10%, V:0.13%, H: 0.00004%, O: 0.0011%, N: 0.004%, and the balance of Fe and other inevitable impurities.

A method for manufacturing a low alloy ultra high strength steel as described above, comprising the steps of:

s1: quantitative weighing, namely weighing all the raw materials according to the components;

s2: smelting, namely smelting the raw materials into steel ingots by adopting a smelting process of smelting and casting in a vacuum induction furnace and vacuum consumable remelting;

s3: forging, namely heating the consumable steel ingot to 1220 ℃, preserving the heat for more than 25h, diffusing to ensure that carbide is dispersed and distributed, discharging from a furnace and forging after diffusion, wherein the open forging temperature is 1195 ℃, the finish forging temperature is 880 ℃, and the steel can be ensured to be formed in the optimal thermoplastic zone in the temperature range, so that forging cracking is avoided;

s4: normalizing at 920 deg.C, keeping the temperature at 2.5 mm/min +60min, and air cooling;

s5: tempering for the first time, treating at 680 ℃, preserving heat at 2.5 mm/min +200min, and cooling in air;

s6: quenching, treating at 900 deg.C, keeping the temperature at 2.5 mm/min +60min, and oil cooling;

s7: and (4) secondary tempering, wherein the tempering is carried out according to salt bath treatment at 260 ℃, heat preservation is carried out according to the ratio of 2.5 mm/min to 60min, and air cooling is carried out.

The mechanical properties of the low-alloy ultrahigh-strength steel prepared by the invention are compared with those of 30CrMnSiNi2 steel, and are shown in Table 1

TABLE 1 comparison of mechanical Properties

The utility model provides a when low alloy superhigh strength steel casting mold specifically uses, the molten steel is pour in the mould that mould 2 and the top mould of falling the ingot constitute at the bottom of, treat the inside steel ingot shaping back of mould, at first start miniature telescopic link 8, miniature telescopic link 8 promotes 7 centre gripping shaping steel ingots of splint, then start electric hydraulic cylinder 10 lifting connecting plate 11, connecting plate 11 drives the top mould of falling the ingot 3 and rises, takes out from the bottom mould 2 of falling the ingot up to the shaping steel ingot, is convenient for realize the drawing of patterns to the shaping steel ingot.