30results about How to "Achieving grain refinement" patented technology

The invention relates to a preparation method of an ultrafine-grain titanium matrix composite material by using a mushy-zone titanium alloy as a matrix. The preparation method comprises the following steps: carrying out hot working of a titanium matrix composite material; cutting to form a blank material, and polishing; simultaneously preheating a sample and a die, and uniformly smearing the surface of the sample and the inner wall of the die with a graphite lubricant; respectively carrying out heating and heat insulation of the die and the sample; putting the sample in a die channel to make the sample completely go through the channel corner of the equal-diameter corner extrusion die, and cooling the sample with water to complete a primary extruding technology; and machining the sample, carrying out 90DEG anticlockwise rotation, beveling the head, and carrying out 2-4 time equal-diameter bending channel extrusion deformation to obtain the ultrafine-grain titanium matrix composite material. The preparation method realizes the strength and plasticity deformation of the titanium matrix composite material, effectively refines the internal crystal grain size, has the advantages of short process flow, easy operation, high efficiency, low cost and strong adaptability, and can be used in the titanium matrix composite material processing field.

The invention relates to a processing method for refining crystal grains and improving texture of double surface layers of a magnesium alloy plate strip. In the method, the magnesium alloy plate strip is arranged between at least two groups of bending rolls which are stacked up and down and staggered mutually at the temperature of between 250 and 400 DEG C; the magnesium alloy plate strip is driven to move towards one direction for at least one pass, and when passing through the bending rolls, the magnesium alloy plate strip are bent and deformed, so the magnesium alloy plate strip of which the crystal grains of the double surface layers are refined and the texture is improved is prepared. In the deformation process, large strain is accumulated on the upper and lower surface layers of the plate strip due to repeated stretching and compression, and dynamic recrystallization is induced at middle and high temperature, so that the crystal grains of the double surface layers of the plate strip are refined; and the surface layers are subjected to shear stress, so that a basal plane deflects to improve the original texture. In the method, a process design is reasonable, and equipment is simple and convenient to operate, can be matched with the conventional processing equipment for magnesium alloy, has high processing efficiency and can improve the rigidity and ductility of the double surface layers of the magnesium alloy plate strip effectively and improve the subsequent processing performance of the magnesium alloy plate strip; and large-scale industrial production is easy to realize.

The invention relates to a rolling-deformation thermal treatment method for improving performance of a bearing ring. The rolling-deformation thermal treatment method comprises the steps of carrying out roll forming on a bearing ring blank to break crystal grins, generating a lot of crystal defects like dislocation and substructures inside the material, and enlarging recrystallization nucleation positions; then, carrying out quenching treatment, dynamic recrystallization nucleation, solid state phase change and dispersion strengthening, and refining the crystal grains to improve the distribution uniformity of the crystal grins; and decreasing the content of retained austenite in the bearing ring through cold treatment, so as to improve the strength, rigidity, toughness and structure stability of the bearing ring considering the problems that the structure quickly cooled through oil quenching or water quenching has retained austenite with a relatively high content, and the retained austenite with the relatively high content influences the size accuracy stability and reduces the strength, rigidity, plasticity and fatigue crack propagation resistance of the bearing ring. According to the rolling-deformation thermal treatment method, the fineness uniformity, mechanical property and size stability of the bearing ring structure are remarkably improved.

The invention discloses a rotary deep drawing forming mold of a thin-wall cup-shaped part. The mold comprises a punch, a forming female mold and a lower mold plate, the forming female mold is coaxially provided with a composite mold cavity allowing a blank to be placed in, the end face of the contact of the punch and the blank is a conical boss mold face, the composite mold cavity is formed through compositing of a V mold cavity in the upper portion and a rectangular mold cavity in the lower portion, the two sides of the connecting position of the V mold cavity and the rectangular mold cavityare each provided with multi-pass arc convex face tables making contact with the blank, the multi-pass arc convex face tables are sequentially mounted from top to bottom, the arc radii of the convex face tables are sequentially increased, the number of the arc convex face tables on one side is larger than that of the arc convex face tables on the other side by one, the forming die mold is an asymmetric annular rotation body, the additional arc convex face table is mounted on the highest position on the side, according to the mold, the steel forming property can be improved, the forming component comprehensive mechanical property can be improved, and the defect that strength differences of all directions of a traditional thin drawing forming thin-wall cup-shaped part are large can be overcome.

The invention provides marine ultrahigh-strength low-temperature steel with excellent fatigue performance and a manufacturing method thereof. The steel comprises the following components in percentage by weight: 0.080%-0.140% of C, 0.20%-0.60% of Si, 1.15%-1.60% of Mn, 0.020%-0.050% of Nb, 0.040%-0.080% of V, 0.30%-0.50% of Cu, 0.50%-0.80% of Ni, 0.0140%-0.057% of N, 0.10%-0.20% of Cr, less than or equal to 0.010% of P, less than or equal to 0.005% of S, 0.015%-0.035% of Als and the balance of Fe and inevitable impurities. The preparation method comprises the steps of smelting, continuous casting, heating, rolling and cooling. The microscopic structure of the low-temperature steel produced through the method is a complex-phase structure of superfine ferrite, bainite and a small amount of martensite, the room-temperature high-cycle fatigue ultimate strength is 320 MPa or above, the fatigue ratio is larger than or equal to 0.52, and the-20 DEG C high-cycle fatigue ultimate strength is 350 MPa or above; according to the low-temperature steel, the yield strength is 500 MPa or above, the tensile strength is 620 MPa or above, the percentage elongation after fracture is 23.0% or above, the impact absorption energy at the temperature of-40 DEG C is larger than or equal to 260 J, and the impact absorption energy at the temperature of-60 DEG C is larger than or equal to 230 J.

The invention discloses a laser impact grain refinement pretreatment auxiliary laser dynamic flexible micro-forming method and device, and relates to the field of laser processing and forming. The device comprises a laser loading system, a plastic forming system, an automatic mold changing system and a clamp system. According to the method, a workpiece is subjected to laser impact pretreatment toachieve grain refinement and then subjected to laser dynamic flexible micro-forming, and grain refinement pretreatment and forming machining are achieved through a movable mold core and a mold core supporting body. According to the method and device, the novel micro-mold is used for carrying out laser impact grain refining pretreatment before laser dynamic flexible micro-forming, so that the forming capability is improved, the micro-forming precision, the surface quality and the forming limit are further improved, and failure behaviors such as breakage caused by a size effect phenomenon are avoided; and meanwhile, the novel automatic mold changing system for the micro mold can avoid secondary clamping, so that the production cost is effectively saved.

The invention provides a steel material for a forged steel brake disc of a high-speed train with the speed of 350 km or above per hour and a forging technology of the steel material. The brake disc is prepared from, by mass, 0.25%-0.29% of C, 0.2%-0.35% of Si, 0.6%-0.9% of Mn, 2.1%-2.5% of Cr, 0.9%-1.1% of Mo, 0.2%-0.3% of V, 0.02%-0.04% of Al, 0.05%-0.08% of Nb and the balance iron and other elements, and the other elements are residual microelements. The blank of steel materials for forging and heat treatment of the high-speed rail brake disc with the speed of 350 km and above in China is filled firstly, the steel materials have the characteristics of fine grain size, uniform structure, normal-temperature performance, low-temperature performance and high-temperature performance, it is guaranteed that various performance requirements of the high-speed rail brake disc with the speed of 350 km and above are met, the raw material cost is saved, and the production cost is reduced. And the range of the steel material for forging the high-speed rail brake disc with the speed of 350 km and above in China can be widened to a certain extent, and localization of the steel material for forging the high-speed rail brake disc with the speed of 350 km and above is achieved.