1315 results about "High strength steel" patented technology

Provided is a high-strength steel sheet having excellent member strength, ductility, stretch flangeability, bendability of a shear end surface, and low-temperature toughness. A high-strength steel sheet having a prescribed component composition and a steel structure in which the area ratio of martensite is 10%-80%, the area ratio of bainite is 2%-70%, the area ratio of ferrite is 80% or less, and the area ratio of retained austenite is 15% or less at a position at 1 / 4 of the sheet thickness. The ratio of the number of martensite blocks in which metastable carbides are present relative to the number of martensite blocks is 2% or more, and the standard deviation [sigma] n of the nano-hardness relative to the average value [Hn] ave of the nano-hardness is 0.60 x [Hn] ave or less when the nano-hardness at 225 points or more is measured at a position of 1 / 4 of the sheet thickness.

The invention discloses copper-containing maraging ultrahigh-strength steel and a preparation method thereof, and belongs to the field of steel and iron materials. The copper-containing maraging ultrahigh-strength steel is prepared from the following chemical components in percentage by mass: 14.5 to 16.0 percent of Co, 17.0 to 18.0 percent of Ni, 6.0 to 8.0 percent of Mo, 1.0 to 1.5 percent of Ti, 0.5 to 1.0 percent of Cu, 0.5 to 1.0 percent of Al and the balance of Fe and inevitable impurities. The preparation method comprises the steps of vacuum smelting, high-temperature homogenization, forging cogging, thermal deformation and thermal treatment. According to the copper-containing maraging ultrahigh-strength steel prepared through the preparation method, under the condition that the grain size is larger than or equal to 8.0, the tensile strength of the material reaches 2800 MPa or above, meanwhile, the elongation of 7% or above is kept, and the application requirements of different fields for the ultrahigh-strength steel with the tensile strength of 2800 MPa or above can be met.

The invention provides a multi-step aging treatment method for improving the toughness of an ultrahigh-strength steel ingot, and belongs to the technical field of steel heat treatment. The treatment method comprises the following steps: carrying out solution treatment on the ultrahigh-strength steel at the temperature above AC3, carrying out water cooling or oil cooling to the room temperature, then carrying out subzero treatment, taking out and recovering to the room temperature; the multi-step aging treatment comprises the first step of single-time or multi-time low-temperature aging at the temperature of 400-550 DEG C and the second step of high-temperature aging at the temperature of 550-650 DEG C, and the ultrahigh-strength steel ingot is obtained. According to the method, the content of reversed austenite is increased, especially film-shaped austenite with stable mechanics is increased, meanwhile, it is guaranteed that a precipitated phase is not obviously coarsened, and good obdurability matching is achieved.

The invention belongs to the technical field of steel pipe welding, particularly relates to high-strength steel pipe welding equipment and process based on a laser-induced hybrid welding technology, and solves the problems of high interference degree and poor correction function in the prior art, the high-strength steel pipe welding equipment comprises a base, and the top of the base is fixedly connected with an outer gear ring and two symmetrically arranged clamping assemblies; a welding assembly is installed on the peripheral face of the outer gear ring and composed of an arc-shaped transmission frame and a limiting transmission frame, the outer gear ring is movably sleeved with the arc-shaped transmission frame, the limiting transmission frame is slidably assembled in the arc-shaped transmission frame, a laser induction head and a welding head are installed on one side of the limiting transmission frame, and the welding assembly is used for welding steel pipes. Through the arrangement of the outer gear ring, the arc-shaped transmission frame and other structures, the continuity and stability of circumferential welding are achieved, the problems of mechanical arm interference and the like are avoided, meanwhile, the adaptability of equipment to steel pipes with different pipe diameters is improved, frequent equipment parameter adjustment or clamp replacement is not needed, and the welding efficiency is remarkably improved.

The invention provides a laser welding method for tailor-welding hot forming steel with the tensile strength exceeding 1500 Mpa after hot forming before hot forming, and particularly relates to a method capable of avoiding cracking of a heat affected zone after welding. The hardness distribution of a heat affected zone is controlled during laser welding cooling, so that the hardness of the heat affected zone after welding does not exceed the highest hardness of a weld joint melting zone, and the highest hardness value does not exceed H / 3-20 HV; (H is the tensile strength of the material obtained after thermal forming); the minimum width of the heat affected zone is not less than 0.2 m; the method specifically comprises the steps that energy distribution of a laser welding heat source is controlled in the welding process, a laser beam forms a flat-top light source on the surface of a workpiece, a welding pool is formed when the light source irradiates the workpiece for welding, the welding pool has the length L and the width B, and L / B is larger than or equal to 3. A welded joint obtained through the laser welding method has excellent post-welding cracking resistance for welding of high-strength steel with the tensile strength exceeding 1500 Mpa after thermal forming.

The invention relates to the technical field of underground engineering, and discloses an automatic pipe jacking machine for pipe jacking construction, which comprises a main frame made of high-strength steel and capable of bearing thrust applied by the pipe jacking machine in the working process; the propelling module comprises a plurality of push rods, and the maximum thrust of the propelling module is 80 tons; the guide modules are arranged on the two sides of the main rack, each guide module is composed of a guide frame and a base, and the pipe jacking machine keeps linear motion in the construction process; the heading head is mounted in front of the propelling module and comprises a cutting tool and a spiral conveyor; the power module is arranged in the heading head, adopts a diesel engine, has the power of 150kW, and provides continuous power for the heading head; and the control module is arranged in the main rack and fixedly mounted on the side wall of the main rack. The reliability of the equipment is improved, and the intelligent monitoring and early warning system is additionally arranged, so that the equipment deviation or damage caused by geological sudden change can be effectively avoided, the construction risk is greatly reduced, and the operation safety and high efficiency are guaranteed.

The invention provides a model predictive control-based steel plate tension dynamic optimization method and system. The method comprises the following steps of: obtaining material characteristic parameters of a high-strength steel plate; according to the material characteristic parameters, predicting the tension change of the high-strength steel plate and defining a voltage regulation parameter range of an electric control valve by utilizing model prediction control so as to generate a voltage regulation instruction matched with the material characteristic parameters; according to the rotating speed adjusting requirement and the real-time load state of the driving motor, an optimized pulse sequence is generated through the pulse modulation technology; determining a duty ratio adjustment direction and a duty ratio adjustment proportion according to the voltage adjustment instruction so as to obtain a pulse sequence after duty ratio adjustment; and by means of the voltage adjusting instruction, the trigger phase of the pulse sequence with the duty ratio adjusted is corrected, so that the rotating speed of the driving motor is synchronously matched with the tension adjusting variable, and synchronous self-adaptive optimization of the tension control response speed and the material characteristic change in the production process of the high-strength steel plate is achieved.

The invention discloses an isomeric low-alloy high-strength steel structure electric arc additive manufacturing process, and relates to the technical field of electric arc additive manufacturing, the isomeric low-alloy high-strength steel structure electric arc additive manufacturing process comprises the following steps: carrying out heat treatment and tensile test on a low-alloy high-strength steel wire to obtain test data, and establishing a process parameter-performance prediction model according to the test data; obtaining a performance demand of a target structural member, and drawing up a process parameter by using a process parameter-performance prediction model according to the performance demand; an electric arc additive manufacturing system is used for conducting electric arc additive manufacturing on the low-alloy high-strength steel wire, and a low-alloy high-strength steel structural part is obtained; acquiring temperature information of the low-alloy high-strength steel structural member by using an infrared thermal imager, and adjusting the process parameters in real time according to the temperature information to obtain a target structural member; gradient distribution of precipitation strengthening phases is achieved, isomerism of alloy element in-situ strengthening low-alloy high-strength steel materials is achieved, and the diversified requirements of target structural parts for different strengths and plasticity are met.

The invention relates to the field of additive manufacturing, and discloses a dynamic phase change control additive ultrahigh-strength steel strengthening and toughening process which comprises the following steps: S1, constructing a phase change structure design target which comprises retained austenite distribution, a structure space structure and mechanical property requirements; s2, based on the phase change structure design target, establishing a free energy model taking a phase field variable as a core for representing a phase change driving behavior between austenite and martensite; s3, on the basis of the free energy model, constructing a multi-field partial differential control model coupling phase field evolution, element diffusion and heat conduction; and S4, in combination with the multi-field partial differential control model, determining an interface adsorption parameter, a diffusion coefficient and a thermophysical parameter based on experimental characterization data. According to the method, path parameters are optimized through a multi-field partial differential control model and tissue deviation feedback, and accurate control of the phase change tissue and dynamic closed-loop adjustment of the machining process are achieved.

The invention provides a dark crack detection method of an ultrahigh-strength steel plate stamping part for a new energy automobile, and relates to the technical field of stamping part detection, and the dark crack detection method comprises the following steps: obtaining a detection area and a reference area of a to-be-detected stamping part; injecting a group of same multi-frequency alternating-current excitation signals into the detection area and the reference area of the to-be-detected stamping part at the same time, and synchronously acquiring a first electrical response signal of the detection area under the multi-frequency alternating-current excitation signals and a second electrical response signal of the reference area under the multi-frequency alternating-current excitation signals; based on the first electrical response signal and the second electrical response signal, calculating a conductivity difference value of the detection area and the reference area at the same frequency point, and obtaining a conductivity difference value-frequency curve comprising a plurality of frequency points; and based on the conductivity difference-frequency curve, whether dark cracks exist in the detection area is judged. According to the detection method, the defect degree can be quantitatively evaluated, and the strict requirement of the new energy automobile industry for quality consistency is met.

The invention discloses low-alloy high-strength steel and a production method thereof. The low-alloy high-strength steel comprises the following chemical components in percentage by weight: 0.14 to 0.18 percent of C, 0.20 to 0.35 percent of Si, 0.65 to 0.75 percent of Mn, less than or equal to 0.025 percent of P, less than or equal to 0.018 percent of S, 0.010 to 0.035 percent of Als, 0.04 to 0.06 percent of Ti, 0.01 to 0.015 percent of Ca, 0.0020 to 0.0050 percent of N and the balance of Fe and inevitable trace elements. The low-alloy high-strength steel is developed by improving the content of microalloy Ti and reducing the content of alloy Mn, the rolling process is optimized according to the behavior characteristics of the second phase of Ti in the hot rolling process, production of the Q420 steel with the Mn content reduced to 0.65-0.75% is achieved, and the excellent impact performance of the Q420 steel is guaranteed.

The invention belongs to the technical field of metal heat treatment, and relates to a rapid quenching and tempering process of high-strength steel, which comprises the following steps: preheating a steel workpiece, then transferring to a vacuum induction furnace, heating to a first quenching temperature, preserving heat, and then periodically fluctuating and controlling the temperature to obtain a quenched workpiece; performing high-frequency induction heating on the quenched workpiece to a first tempering temperature, preserving heat, and performing water cooling after heat preservation to finish first tempering treatment; and then carrying out medium-frequency induction heating to a second tempering temperature under the alternating magnetic field, preserving heat, and air-cooling to room temperature along with the furnace after heat preservation is finished, so as to finish second tempering treatment. By optimizing key steps such as preheating, quenching, cooling and tempering in the heat treatment process, the comprehensive mechanical property of the high-strength steel is remarkably improved, rapid heating and structure homogenization are achieved through two-section preheating, and the problem of workpiece deformation or cracking caused by rapid heating in a traditional preheating process is solved.

The invention provides a laser welding method for an unequal-thickness heterogeneous hot-formed steel joint by cooperatively regulating and controlling annular light spots and light beam deflection. The method comprises the following steps: firstly, pretreating, clamping and positioning the PHS1500 and PHS2000 unequal-thickness ultrahigh-strength steel plates; then, the deflection angle of the light beam is adjusted to be within the range of-30 degrees to + 30 degrees; and finally, a galvanometer control system is used for driving a laser beam to conduct swing scanning in a circular track, and welding is completed under the condition that parameters such as laser power, welding speed, swing frequency, the ratio of swing amplitude to core ring energy and the like are set. According to the method, wire filling is not needed, the PHS1500 and PHS2000 butt welding joints can be effectively connected within the light beam deflection angle range of-30 degrees to + 30 degrees, efficient connection can be achieved within the light beam deflection angle range of-20 degrees to + 20 degrees, weld joint forming is effectively improved, weld joint grains are refined, and the problems of stress concentration and welding softening areas caused by different thicknesses and different strengths of plates are solved. And within the light beam deflection angle range of-20 degrees to + 20 degrees, the obtained joint welding seam is well formed, the tensile strength can reach 1400 MPa or above, and the method is suitable for manufacturing the tailor-welded structure of the unequal-thickness plates of the automobile body.

The invention discloses a method for controlling the thickness difference of a cold-rolled ultrahigh-strength steel plate with the tensile strength larger than or equal to 800 MPa. The method comprises the steps that in the steel coil transportation process, a hot coil saddle bears a steel coil, and heat insulation treatment is conducted between the hot coil saddle and the steel coil, so that the direct contact time between the hot coil saddle and the steel coil does not exceed the set time. According to the thickness difference control method for the cold-rolled ultrahigh-strength steel plate with the tensile strength larger than or equal to 800 MPa, the thermal insulation pad is additionally arranged on the hot rolling saddle, the situation that the time of direct contact between the hot rolling saddle and the steel coil exceeds the set time in the transportation process is avoided, the thickness difference amplitude and length are effectively reduced, and the product percent of pass is increased.

The invention provides corrosion-resistant 960MPa-grade high-strength steel. The corrosion-resistant 960MPa-grade high-strength steel comprises the following chemical components in percentage by mass: 0.07 to 0.13 percent of C, 0 to 0.1 percent of Si, 0.4 to 0.68 percent of Mn, 0.025 to 0.045 percent of P, less than or equal to 0.010 percent of S, 0.015 to 0.04 percent of Als, 0.03 to 0.06 percent of Ti, 0.001 to 0.003 percent of B, 0.1 to 0.4 percent of Cu and the balance of Fe and impurities. The invention further discloses a machining method of the corrosion-resistant 960MPa-grade high-strength steel. The Cu-P composite adding technology is innovatively adopted to replace traditional precious metal, and the alloy cost is remarkably reduced on the premise that the corrosion resistance is guaranteed. Compared with high-strength steel containing precious metal such as Mo in the prior art, the material cost can be reduced, and the strict requirement of the engineering machinery industry for economical efficiency is met.

The embodiment of the invention discloses ultrahigh-strength steel and a preparation method thereof, relates to the technical field of heat treatment, and can effectively improve the strength, corrosion resistance and high temperature resistance of the steel. The ultrahigh-strength steel comprises the following chemical components in percentage by weight: 0.05 to 0.20 percent of C, 0.10 to 0.25 percent of Mn, 0.50 to 1.00 percent of Si, 6.00 to 8.00 percent of Cr, 7.00 to 10.00 percent of Ni, 1.00 to 3.00 percent of Cu, 0.00 to 0.40 percent of V, 0.01 to 0.06 percent of Nb, 1.00 to 3.00 percent of Mo, 2.00 to 4.00 percent of Al, less than or equal to 0.02 percent of P and the balance of Fe. S is less than or equal to 0.02%. The method is suitable for production and manufacturing scenes of the ultra-high-strength steel.

The invention relates to the technical field of metal smelting, and discloses a method for improving the stability and uniformity of the content of Mn in double-vacuum 300M steel, a vacuum arc consumable electrode is smelted through a vacuum induction furnace (VIM) process, and the content of Mn in the electrode is controlled within the Mn target component * (1.43-1.67); during vacuum arc consumable remelting, in the arc starting stage, the vacuum degree is set to be in an ultimate vacuum state, and a current + voltage control mode is adopted; in the smelting stage, 0.15-0.20 Pa of argon is filled into a vacuum chamber, and a melting speed and molten drop control mode is adopted; and in the feeding stage, 0.30-0.35 Pa of argon is filled into a vacuum chamber, and a current + voltage control mode is adopted. According to the method, the Mn content uniformity of the double-vacuum medium-low alloy ultra-high strength steel vacuum consumable ingot and the stability between furnace batches can be effectively improved, and meanwhile the vacuum degassing capacity in the vacuum consumable process and the energy utilization efficiency in the smelting process are both considered.

The present application relates to a low-yield ratio 420MPa low-alloy high-strength steel and a preparation method, belonging to the technical field of steel manufacturing. In terms of mass fraction, the chemical composition of the low-alloy high-strength steel includes: C: 0.07% to 0.12%, Si: 0.10% to 0.40%, Mn: 1.60% to 1.80%, P: ≤0.015%, S: ≤0.010%, Alt: 0.020% to 0.060%, Nb: 0.03% to 0.05%, Ti: 0.01% to 0.03%, N≤0.005%, and matrix element Fe. The composition design gives full play to the solid solution strengthening of C and Mn and the fine grain strengthening and precipitation strengthening of Nb and Ti microalloys. At the same time, the continuous full annealing process does not require slow cooling treatment, which improves production efficiency and obtains low-cost, low-yield ratio 420MPa low-alloy high-strength (yield ratio ≤0.8) steel with both strength and excellent plasticity. This type of steel can withstand greater plastic deformation while meeting higher strength requirements without plastic instability, achieving the needs of lightweight automotive industry and excellent stamping integral forming of structural parts, and has broad application prospects.

The invention relates to the technical field of alloys, and discloses 2400MPa-grade ultrahigh-strength steel and a preparation method thereof. The 2400 MPa grade ultrahigh-strength steel comprises the following chemical components in percentage by mass: 0.3%-0.5% of C, 1.0%-2.5% of Si, 3.5%-5% of Mn, 0.2%-0.3% of V, 1%-3% of Ni, 0.02%-0.05% of Nb, 0.3%-0.5% of Mo, 0.5%-2% of Cr and the balance of Fe and inevitable impurities. The microstructure of the 2400 MPa grade ultra-high strength steel comprises martensite and austenite, the average grain size of the martensite ranges from 0.4 micrometer to 2.0 micrometers, and the ratio of the grain length axis to the grain length axis of the martensite is smaller than or equal to 1.6. The strength, plasticity and toughness of the 2400MPa-grade ultra-high-strength steel are improved, and the 2400MPa-grade ultra-high-strength steel has high strength, high plasticity and high toughness.

Provided is a steel sheet that may be used for automobile parts and the like, and to a steel sheet having an excellent balance of strength and ductility, an excellent balance of strength and hole expansion ratio, and an excellent yield ratio evaluation index, and a method for manufacturing the same. The steel sheet includes: by wt %, C: 0.1 to 0.25%, Si: 0.01 to 1.5%, Mn: 1.0 to 4.0%, Al: 0.01 to 1.5%, P: 0.15% or less, S: 0.03% or less, N: 0.03% or less, B: 0.0005 to 0.005%, a balance of Fe, and unavoidable impurities; and as microstructures, bainite, tempered martensite, fresh martensite, retained austenite and unavoidable structures.

The invention belongs to the technical field of manufacturing of low-alloy high-strength steel, and particularly relates to atmospheric corrosion resistant HC260LA low-alloy high-strength steel and a production method of the atmospheric corrosion resistant HC260LA low-alloy high-strength steel. 0.15% to 0.30% of Si; 0.40% to 0.60% of Mn; 0.06% to 0.10% of P; less than or equal to 0.015% of S; 0.02% to 0.08% of Al; 0.10% to 0.20% of Cu; 0 to 0.15% of Ti; 0 to 0.09 percent of Nb; 0.001% to 0.006% of N; and the balance of Fe and inevitable impurities. According to the method, the blocking effect of segregation of P-Cu elements on the grain boundary on a corrosion path is utilized, low-temperature rolling is combined, a three-dimensional corrosion-resistant system of fine grain strengthening, substructure strengthening and rust layer protection is constructed, and the weather resistance, the corrosion resistance and the mechanical property are jointly improved.

The invention relates to a high-strength steel wire winding reinforced pipe fitting and a using method thereof, and belongs to the technical field of steel wire winding reinforced pipe fittings. When the high-strength steel wire winding reinforced pipe fitting is used in a fire-fighting pipeline system and high-pressure water flow impacts an inner rubber layer, a first sliding part moves in the axial direction of a guide rail and cooperates with a spring part to form first-stage buffering; the peak impact force is converted into elastic potential energy; when pressure fluctuates to trigger a limiting part, the arc-shaped outer edge of a swing rod makes contact with a stop lever to generate a lever effect, a second sliding part is forced to move reversely, rigid stress borne by an outer rubber layer is converted into flexible deformation of a middle buffer layer, and a rigidity abrupt change interface is effectively eliminated. And meanwhile, a multidirectional displacement compensation mechanism under the constraint of the guide rail is utilized, the reflectivity of high-frequency vibration energy is reduced, and the problem that a stress transmission path is interrupted due to the fact that a rigidity abrupt change interface is formed by a low-rigidity buffer layer and a high-rigidity outer rubber layer is fundamentally solved.

The invention relates to the technical field of steel and iron materials, and discloses tungsten-containing maraging ultrahigh-strength steel and a preparation method thereof. The tungsten maraging ultrahigh-strength steel comprises, by mass, 14.5%-16.0% of Co, 17.0%-18.0% of Ni, 6.0%-8.0% of Mo, 1.0%-1.5% of Ti, 0.5%-1.0% of W and the balance Fe and inevitable impurities, and the impurity elements are controlled according to the requirements that C is smaller than or equal to 0.008%, Si is smaller than or equal to 0.1%, Mn is smaller than or equal to 0.1%, P is smaller than or equal to 0.005%, S is smaller than or equal to 0.005%, N is smaller than or equal to 0.0015%, and O is smaller than or equal to 0.0015%. Based on calculation and research results of a first principle that element doping influences a precipitated phase in the maraging steel, 0.5-1.0% of W element is added into a component system of the maraging steel, meanwhile, the content of Mo element in the steel is increased, and under the condition that the grain size of the steel is larger than or equal to 8.0 level, the tensile strength Rm is larger than or equal to 2800MPa, and the elongation A is larger than or equal to 5%.

The invention discloses a treatment process and a production line of a variable-strength automobile anti-collision beam rolling profile, and relates to the technical field of automobile anti-collision beam manufacturing, and the treatment process comprises the following steps: material selection and primary leveling; local heating and cooling; secondary leveling and punching are carried out; and carrying out primary cold roll forming and secondary cold roll forming. According to the treatment process, the strength of the target position of the ultra-high-strength steel forming plate is changed, so that the problem of cracking cannot occur when the small fillet of the ultra-high-strength steel forming plate is bent, a rolling production line can normally operate for a long time, and the production efficiency is guaranteed.

According to the double-arc low-stress welding device and method for the high-strength steel structural part, two symmetrically-distributed welding mechanical arms are used for achieving symmetrical welding of welding seams on the two sides of the structural part, a vibration exciter vibrates along with welding in the welding process, and vibration aging is conducted after welding; the vibration pickup display screen can reflect vibration frequency, vibration time and vibration waves, and the ultrasonic stress detector monitors the welding stress state of the structural member in real time; double-arc symmetrical welding enables welding shrinkage to be generated uniformly, and welding deformation is reduced; welding stress and a molten pool can be regulated and controlled in real time along with vibration in the welding process, so that the welding molten pool is in a vibration state, slag inclusion and air hole escape is facilitated, and welding seam forming and organization are optimized; the ultrasonic stress detector monitors the welding stress state of the structural part in real time, quantitative control over the welding process of the structural part is achieved, and the stress state and welding deformation control consistency of the structural part is guaranteed. Welding deformation and welding residual stress can be effectively controlled, heat treatment after welding is not needed, and the component quality is improved.

A high strength steel sheet having 1180 MPa or higher tensile strength and a method for manufacturing the same are disclosed. The high strength steel sheet has a specific chemical composition and is such that in a region at ¼ sheet thickness, the area fraction of martensite is 80% or more, the volume fraction of retained austenite is 3% or more and 15% or less, the area fraction of the total of ferrite and bainitic ferrite is 10% or less, the average grain size of prior austenite is 20 μm or less, and the average of the proportions of packets having the largest area in prior austenite grains is 70% by area or less of the prior austenite grain.

The invention discloses a method for improving impact toughness of aluminum-containing ultrahigh-strength steel. The method comprises the following steps: forging an aluminum-containing ultrahigh-strength steel cast ingot; carrying out two-stage hot rolling on the forged ultrahigh-strength steel, and carrying out water cooling treatment after hot rolling; the hot-rolled ultrahigh-strength steel is annealed at the annealing temperature of 800 + / -50 DEG C, heat preservation is conducted for a period of time, furnace cooling is conducted to 600 + / -50 DEG C, and discharging and air cooling are conducted; the ultrahigh-strength steel is subjected to solid solution and aging treatment, the solid solution process comprises the steps that a heat treatment furnace is heated to 950-1000 DEG C for charging, heat preservation is conducted for 30-40 min, then oil cooling is conducted, the aging process comprises the steps that heat preservation is conducted for 55-65 min at the temperature of 500-550 DEG C, and then air cooling is conducted. The technology is scientific and reasonable, the toughness of the aluminum-containing ultrahigh-strength steel is greatly improved while the strength of the ultrahigh-strength steel is guaranteed through the combination of two-stage rolling and the reasonable heat treatment technology, and therefore the service safety of the aluminum-containing ultrahigh-strength steel is improved.

Provided are a short-cut carbon fiber composite (SCFC)-high strength steel (HSS) hybrid bionic structure battery box and its integrated forming method. A SCFC-HSS hybrid bionic structure lower box body includes a lower box framework made of high strength steel and a SCFC lower box matrix; and an upper box body and the lower box are connected by bolts to form a complete SCFC-HSS hybrid bionic structure battery box. A high strength steel lower box framework scheme is designed based on the principle of bionics, then welding and surface treatment are carried out to obtain a bionic lower box framework structure, and the bionic lower box framework structure is placed in a mold for integrated injection molding using a SCFC matrix material.

The invention discloses a 1180MPa-grade ultrahigh-strength steel plate for an automobile and a preparation method of the 1180MPa-grade ultrahigh-strength steel plate, and belongs to the technical field of cold-rolled strip production. The steel plate comprises the following chemical components in percentage by mass: 0.17%-0.20% of C, 1.2%-1.6% of Si, 1.70%-2.10% of Mn, less than or equal to 0.008% of P, less than or equal to 0.005% of S, 0.30%-0.50% of Al, 0.15%-0.30% of Cr, 0.08%-0.12% of V, less than or equal to 0.0045% of N and the balance of Fe and impurities, wherein Ceq = C + Si / 30 + Mn / 20 + 2P + 4S < = 0.41. The preparation method comprises the steps of smelting, continuous casting, hot rolling, pickling cold rolling and continuous annealing. Through alloy component design and process collaborative optimization, the prepared ultrahigh-strength steel plate has high strength, high plasticity and high reaming performance, and the problem that existing bainite complex-phase steel is poor in comprehensive performance can be effectively solved.

The invention relates to ultrahigh-strength steel for ocean engineering and a manufacturing method thereof, belongs to the technical field of steel for ocean engineering, and solves the problems of poor low-temperature toughness, poorer weldability, insufficient corrosion resistance, higher manufacturing and welding cost and the like of ultrahigh-strength steel in the prior art. The invention provides ultrahigh-strength steel for ocean engineering. The steel for ocean engineering comprises the following components in percentage by mass: 0.020%-0.050% of C, 6.00%-10.00% of Ni, 1.50%-3.50% of Cu, 0.60%-1.0% of Mo, 0.80%-1.50% of Cr, 0.60%-1.0% of Mn, 0.10%-0.30% of Si, 0.040%-0.060% of V, 0.010%-0.020% of Ti, 0 < N < = 0.04%, < = 0.005% of P, < = 0.003% of S and the balance of Fe and inevitable impurities. The steel for ocean engineering is excellent in comprehensive performance, good in obdurability matching degree, excellent in welding performance and capable of achieving low-temperature preheating welding.