57results about How to "Play the role of fine grain strengthening" patented technology

The invention relates to the field of third-generation advanced high-strength steel used for automobiles and discloses 1180 MPa-grade ultrahigh-strength low-cost cold-rolled quenched partition steel and a manufacturing method thereof. A steel plate comprises the chemical components including, by mass percent, 0.18-0.22% of C, 1.0-3.0% of Mn, 1.0-2.0% of Si, not greater than 0.05% of P, not greaterthan 0.02% of S, 0-0.05% of Nb, 0-0.2% of Ti and the balance iron and inevitable impurities. The steel plate manufacturing method relates to the process of steel smelting, hot rolling, cold rolling,pre-quenching and heat treatment, and finally, a ferrite-bainite-martensite-retained austenite mixed structure is obtained. According to the 1180 MPa-grade ultrahigh-strength low-cost cold-rolled quenched partition steel and the manufacturing method thereof, on the basis of traditional C-Mn-Si series quenched partition steel, Nb and Ti elements are added for refining the structure, pre-quenching treatment and a one-step partition process are adopted, finally the ultrahigh-strength quenched partition steel with the yield strength being 500-800 MPa, the tensile strength not smaller than 1180 MPa, the elongation after fracture not smaller than 20% and the product of strength and elongation not smaller than 24GPa.% is obtained, and the mechanical property is quite excellent.

The invention discloses Mo-C-N-Si-Nb gradient coating material and a preparation method thereof. One side or two sides of Mo-Nb alloy are provided with composite coatings. The composite coatings are gradient coatings with Si, C and N content gradually increasing and Mo and Nb content gradually decreasing from inside to outside along the Mo-Nb alloy direction. The gradient coatings are tightly combined with a base. The gradient coatings are high in bending strength. Steady-state creep rate of base material is 3 levels lower than that of pure Mo monocrystal. The surface of the coatings has high silicon content. The surface layers of the coatings are mainly made from, MoSi2, SiC, Si3N4 and Si, the middle layers of the coatings are mainly made from MoSi2, SiC and Si3N4, and transition layers of the coatings are mainly made from Mo5Si3, MoSi3 and a trace of NbSi2. No cryogenic pulverization occurs in low-temperature oxidation experiment at 500 DEG C, and the coatings are high in high-temperature oxidation resistance. The preparation method has the advantages that the formation speed of gradient layers is high, the preparation time is short, and the thickness of the coatings is free to control. The Mo-C-N-Si-Nb gradient coating material has the advantages of compact surface structure, fine high-temperature creep resistance, fine high-temperature oxidation resistance and the like.

The invention discloses a high-strength Mg-Gd-Y-Zn-Zr rare-earth magnesium alloy. The high-strength Mg-Gd-Y-Zn-Zr rare-earth magnesium alloy comprises the following chemical components in percentage by mass: 10.8%-13.6% of Gd, 4.0%-4.6% of Y, 1.8%- 2.2% of Zn, 0.4%-0.6% of Zr and the balance of magnesium and inevitable impurity elements. The invention further discloses a preparation method of the high-strength Mg-Gd-Y-Zn-Zr rare-earth magnesium alloy. The preparation method sequentially comprises the following steps: (1) preparing a magnesium alloy cast bar; (2) homogenization of the bar: heating the magnesium alloy bar and preserving heat by adopting a grading homogenization system, then heating and reheating, preserving heat and carrying out homogenization treatment; and (3) upsetting-extruding composite deformation: putting the bar into a heated upsetting-extruding composite die, and obtaining a high-toughness deformed-state heat-resistant rare-earth magnesium alloy material after multiple times of circulating upsetting-extruding; (4) solid solution and aging treatment: adopting solid solution and aging treatment for heat treatment, and preserving heat, and quenching by adopting hot water after discharging; and after cooling to room temperature, aging and preserving heat. The magnesium alloy prepared through the preparation method is high in quality, and particularly can keep high mechanical performance at a temperature of 300 DEG C.

The invention discloses steel for an engine non-quenched and tempered expanded-forged connection rod, and a preparation method for a fine-grain forged piece. A preparation method for the steel for theconnection rod comprises the steps that non-quenched and tempered steel is rolled into a phi37-40 bar, and the bar is subjected to initial rolling, water cooling, precision rolling, water cooling andfinal rolling, wherein the rolling heating temperature is 1150-1200 DEG C, the initial rolling temperature is 1110-1160 DEG C, the precision rolling temperature is 860-900 DEG C, and the final rolling temperature is 830-860 DEG C. The preparation method for the fine-grain forged piece for the connection rod comprises the steps of blanking, induction heating, roll forging, air blowing, forging molding, punching and edge cutting, shaping, and controlled cooling, wherein the connection rod induction heating temperature is 1260-1280 DEG C, the roll forging temperature is 1200-1250 DEG C, and theforging molding temperature is 1050-1100 DEG C. According to the connection rod prepared through the steel and the method, the grain size of the connection rod is effectively decreased, the material strength, toughness and plasticity are improved, and the production technology is simplified.

The invention provides a stirring head for friction stir welding and a fabrication method of the stirring head. The stirring head for friction stir welding comprises the following raw materials basedon percent by mass: 55-85% of tungsten powder, 5-15% of rhenium powder and 10-30% of zirconium carbide and/or hafnium carbide powder. The fabrication method of the stirring head for friction stir welding comprises the following steps of A, preparing matrix alloy powder; B conducting pressing and forming, specifically conducting pressing and forming on the matrix alloy powder obtained in the step Ato obtain a formed blank; C, performing high-temperature sintering, specifically sintering the formed blank in the step B to obtain a sintered blank; and D, performing hot isostatic pressure processing. By introducing elements such as rhenium, zirconium carbide and/or hafnium carbide into a tungsten matrix, the plasticity and the processability can be remarkably improved, and the zirconium carbide and/or hafnium carbide is distributed in the tungsten matrix in a diffusion way so as to achieve an effect of fine-grain strengthening; and meanwhile, a W-C chemical bond can be formed at an interface bonding position, so that the enhancement effect can be further improved.

The invention provides an ultra-light high-modulus high-strength casting aluminum-lithium matrix composite and a preparation method thereof. The aluminum-lithium matrix composite comprises a matrix alloy and a strengthening phase, the matrix alloy comprises the following elements of, by mass, 2.5%-3.5% of Li, 1%-2.5 % of Cu, 0.4%-0.5% Mg, 0.15%-0.2% of Sc, 0.15%-0.2% Zr, 0-0.2% of Cd, less than 0.2% of the total content of impurity elements and the balance Al; and the strengthening phase is TiB2. The preparation method comprises the steps that Ti B2/Al base metal alloy is prepared by using in-situ synthesized reaction; and then the TiB2/Al base metal alloy, pure aluminum and Al-Cu, Al-Li and other intermediate alloys are smelted to obtain a composite, and after specific solid solution andaging treatment are carried out, the ultra-light high-modulus high-strength casting aluminum-lithium matrix composite is obtained. The ultra-light high-modulus high-strength casting aluminum-lithium matrix composite has higher strength and elastic modulus and lower density, and has lower cost meanwhile.

The invention belongs to the field of stainless steel metal materials, and particularly relates to microalloy element Nb reinforced double-phase stainless steel and a preparation method thereof. The double-phase stainless steel is prepared from components in percent by mass including smaller than or equal to 0.03% of C, smaller than or equal to 1.0% of Si, smaller than or equal to 2.0% of Mn, smaller than or equal to 0.02% of S, smaller than or equal to 0.03% of P, 21%-23% of Cr, 4.5%-6.5% of Ni, 2.5%-3.5% of Mo, 0.03%-0.05% of Nb, 0.08%-0.20% of N and the balance Fe and inevitable impurities.According to the double-phase stainless steel, a trace of Nb element is added into 2205 double-phase stainless steel, the 2205 stainless steel has more excellent mechanical performance, meanwhile, the corrosion resistance of the 2205 double-phase stainless steel is not reduced, the cost of the double-phase stainless steel can be effectively reduced, the application range of the double-phase stainless steel is widened, the preparation method is simple, and important engineering application value and remarkable economic benefits are achieved.

The invention discloses a rare earth magnesium alloy and a preparation method thereof. The rare earth magnesium alloy contains the following components in percentage by mass: 8.4-8.7% of Al, 0.85-0.89% of Zn, 0.28-0.30% of Mn, 0.39-1.21% of Nd, 0.41-0.43% of Er, less than 0.04% of impurity elements (Si, Fe and Cu) in total, and the balance of Mg. According to the method, rare earth elements Nd and Er are compounded and added in a magnesium alloy by smelting so as to modify the magnesium alloy and the obtained casting-state rare earth magnesium alloy is subjected to T6 heat treatment. Compared with the prior art, the rare earth magnesium alloy prepared by the method is relatively high in room-temperature tensile strength and high-temperature tensile strength and the plasticity is enhanced greatly.

The invention discloses a preparation method for an SnBi-series lead-free solder containing graphene and a MAX phase, and belongs to the technical field of low-temperature welding materials. The mass fraction of the graphene is 0-0.1%; the mass fraction of titanium aluminum carbide is 0-1.0%; and the balance is tin-bismuth binary eutectic alloy. The invention further discloses a preparation method for a lead-free solder. The brazing filler metal alloy is of an eutectic structure, is low in melting point, uniform in microstructure and good in wettability, does not contain toxic and harmful elements, is environment-friendly, and is suitable for the field of low-temperature soft soldering.

The invention relates to a heat treatment method capable of improving an elongation rate of a PCRni3MOVA material forge piece. The method comprises the following steps that normalizing is conducted toheat to 610-650 DEG C firstly, then heating up to 880-900 DEG C is conducted, then heat preservation is conducted, and cooling to a room temperature is conducted; quenching is conducted to heat to 610-650 DEG C firstly, then heating up to 860-880 DEG C is conducted, the heat preservation is conducted, cooling and quenching are conducted, taking out of a furnace is conducted, and water cooling, air cooling, secondary water cooling and oil cooling are conducted for cooling and quenching; tempering at a high temperature is conducted to heat to 320-350 DEG C firstly, then preserving heat is conducted, and then heating up to 580-610 DEG C is conducted; after the furnace cooling to 400 DEG C is conducted, and taking out of the furnace is conducted for the air cooling. According to the method, the heat treatment mode of normalizing, cooling and quenching and high-temperature tempering is adopted, the material forge piece with a effective section phi 101 mm to phi 250 mm can be subjected to heat treatment, the elongation rate of the material forge piece subjected to the heat treatment can reach 16%-19%, technical requirements of an ultra-high pressure container forge piece can be met, andthe production process is high in operability.

The invention provides fine-grain steel for an engineering machinery track link section and a preparation method thereof. The fine-grain steel comprises the following chemical components: by mass, 0.30-0.38% of C, 0.20-0.30% of Si, 1.15-1.35% of Mn, less than or equal to 0.013% of P, less than or equal to 0.003% of S, 0.020-0.032% of Al, 0.0017-0.0030% of B, less than or equal to 0.06% of V, lessthan or equal to 0.04% of Ti, 0.18-0.24% of Cr, less than or equal to 0.012% of Ni, less than or equal to 0.04% of Cu, less than or equal to 0.02% of Mo, less than or equal to 12*10<-6> of [O], less than or equal to 44*10<-6> of [N], and the balance Fe and inevitable impurities. Through the reasonably designed chemical components, the purity of molten steel is improved, heating and rolling technological parameters are controlled, the components of the steel are designed reasonably, the purity and performance of the steel are improved, and the grain size is refined. The fine-grain steel produced through the preparation method has excellent strength and toughens, is fine and uniform in grain size and has the low-power non-metallic inclusion and surface quality.

The invention relates to a photocuring 3D printing nanoparticle reinforced metal part and a preparation method thereof. The preparation method comprises the following steps that after amorphous powder and a coating agent are mixed, a coupling agent and metal powder are added into a mixture at the set temperature, and stirring is carried out for coating; post-treatment is carried out on a product obtained in the coating step, and an amorphous layer coated metal powder material is obtained; the amorphous layer coated metal powder material, photosensitive resin, an ultraviolet light initiator and a dispersing agent are prepared into a photocuring 3D printing slurry; a photocuring 3D printer is used for carrying out photocuring forming treatment on the photocuring 3D printing slurry, and a photocuring 3D printing biscuit is obtained; and degreasing and sintering treatment are carried out on the photocuring 3D printing biscuit, and the photocuring 3D printing nanoparticle reinforced metal part is obtained. According to the photocuring 3D printing nanoparticle reinforced metal part and the preparation method, the metal powder is prepared into the amorphous layer coated metal powder material with a powdery core-shell structure, so that the dispersity of the metal powder in the photosensitive resin slurry is improved, and the photocuring 3D printing nanoparticle reinforced metal part is prepared.

The invention relates to a welding material, in particular to a lead-free solder in the field of submerged-arc welding. The lead-free solder comprises, in weight percent, 0.2-0.8% of Cu, 0.075-0.5% of Ni-V alloy particles, 0.1-1.2% of nano ZrO2 particles and the balance Sn. The invention further relates to a preparation method which includes the steps: uniformly mixing components of the lead-free solder according to the mass ratio and then placing the components into an Al2O3 crucible; placing the crucible in a 400-600 DEG C resistance furnace for smelting; keeping the temperature for 100min to 200min after complete smelting; sufficiently stirring the components after keeping the temperature; discharging the components and pouring the components into a solder bar mould; cooling the components to obtain a lead-free solder bar. The lead-free solder has the advantages that wetting property is fine, electromagnetic induction is not generated, the lead-free solder has a fine creep performance and resistant to oxidation and the like.

The invention provides a method for preparing lightweight special-shaped steel by a sandwich sintering method. The method comprises the following steps that prepared special-shaped steel powder, a binding agent, a pore-forming agent and a steel plate serving as the middle layer are adopted for rolling and forming, then drying and removing the drying agent, sintering and forming by adopting an electromagnetic field sintering method, and then the pore-forming agent is dissolved in the water solution so as to obtain a required foam steel. According to the method, the steel plate is adopted as themiddle layer of the sandwich rolling method so that the overall strength and toughness of the foam steel product can be remarkably improved; the strength of the foam steel finished product can be remarkably improved by applying rare earth elements such as Ce in the powder; in the sintering process, an additional magnetic field and an electric field are applied so that the diffusion effect of theelements in the powder can be remarkably improved, the density of the foam steel can be increased, strength is improved, and therefore the light-weight special-shaped steel with excellent mechanical properties is obtained; the method has the advantages of being simple to operate, low in cost, capable of continuously preparing the light special-shaped steel, high in yield and capable of preparing the light special-shaped steel with the excellent mechanical properties. The invention belongs to the field of metallurgy technology and material science.

The invention relates to a 1300Mpa grade high tenacity cold-formed steel plate and a production method thereof and belongs to the technical field of metallurgy. The steel plate comprises the chemical components in percent by mass: 0.1-0.2% of C, 1.8-2.5% of Mn, less than or equal to 0.005% of S, less than or equal to 0.02% of P, 1.0-1.5% of Si, less than or equal to 0.08% of Als, 0.01-0.04% of Nb, 0.02-0.08% of Ti, 1.0-2.0% of Ni and the balance Fe and inevitable impurities. The production method comprises the following steps: steelmaking, continuous rolling, heating, rolling, pickling, continuous annealing and level pulling straightening. A temperature of a soaking zone in the continuous annealing step is 760-820 DEG C, and an insulating time is 60-225s. The yield strength of the steel plate is greater than or equal to 850 MPa, a tensile strength is greater than or equal to 1300 MPa, and a ductility A50 is greater than 8%. The steel plate has a good cold-forming property and meets a requirement on light weight steel for an automobile.