39results about How to "Avoid cracking tendencies" patented technology

The invention provides a method for preparing a continuous alumina-based ceramic fiber, which relates to an alumina-based ceramic fiber, in particular to a method for preparing a continuous alumina-based ceramic fiber which takes alumina as a main component and adds a second component as a crystalling phase inhibitor. The invention provides a method for preparing the continuous alumina-based ceramic fiber, which is simple in technique and low in cost. The method comprises the steps: preparing alumina sol; preparing silicon dioxide sol; mixing the alumina sol and the silicon dioxide sol to obtain biphase sol, and adding a spinning addition agent into the biphase sol; condensing the biphase sol added with the addition agent and spinning by a dry method to obtain the gel fiber; pyrolyzing the gel fiber to obtain the ceramic fiber; and sintering the ceramic fiber to obtain the continuous alumina-based ceramic fiber.

The invention relates to a novel nickel-free grate material for a sintering machine, which mainly solves the technical problems of insufficient oxidation resistance and low service life of the existing grate. The material comprises the following chemical components in percentage by weight: 1.20 to 2.00 percent of C, 1.5 to 2.5 percent of Si, 1.5 to 2.5 percent of Mn, less than 0.06 percent of S, less than 0.06 percent of P, 11 to 20 percent of Cr, 0.3 to 0.8 percent of Mo, 0.02 to 0.03 percent of Nb, 0.02 to 0.03 percent of Ti, 0.05 to 0.2 percent of modificator and the balance of iron. A novel multi-element high-temperature resistant alloy with good high-temperature oxidation resistance and abrasion resistance can be obtained through the design of reasonable components and the multi-element alloying treatment. The service life of the grate material for the sintering machine is greatly prolonged, the using cost is reduced, the labor intensity is reduced, the operability of a sinteringtrolley is improved, and the quality stability of sintered ore is also improved.

The invention discloses a laser selective area impact-additive composite manufacturing method for a three-dimensionally reinforced shape memory alloy, which comprises the following steps: designing a three-dimensional laser shock-strengthened structural model of a component, generating impact-strengthened path information for each layer; the additive manufacturing control system based on The alloy component model and process parameters are used to manufacture a single deposition layer; the laser shock strengthening control system extracts the impact strengthening path information of this layer, applies preheating to the deposited component as required, and performs laser shock treatment; and so on until the entire component forming and manufacture. By controlling the graphic structure and process parameters of the laser shock, the invention can accurately control the deformation state of austenite and martensite in the three-dimensional direction and the forward and reverse phase transformation of martensite in the shape memory alloy in situ, and realize the solid phase transformation of the alloy. , high-efficiency, high-quality integrated control and optimization of superelasticity and shape memory effects, providing new manufacturing methods and means for complex structures and high-performance shape memory alloys.

The invention discloses a plasma-surfacing iron-based Cr3C2 hypereutectic wear-resistant coating layer added with micrometer Ti and a preparation method thereof and belongs to the technical field of wear-resistant coating layers on the surfaces. The plasma-surfacing iron-based Cr3C2 hypereutectic wear-resistant coating layer is prepared from the following components in percent by mass after plasmasurfacing: 49%-69.5% of iron-based self-fluxed alloy powder, 30%-50% of micrometer Cr3C2 powder and 0.5%-1% of micrometer Ti powder. The plasma-surfacing iron-based Cr3C2 hypereutectic wear-resistantcoating layer is prepared by the following steps: pretreatment of base materials, preparation and drying of composite powder, preparation of the coating layer and post heat treatment. By use of the technical scheme disclosed by the invention, on the basis of improving the hardness and wear resistance of the plasma-surfacing iron-based hypereutectic wear-resistant coating layer enhanced by multiscale particles, the process characteristics of the coating layer can be obviously improved, and the generation of cracks of the coating layer can be effectively prevented.

The invention discloses an aluminum alloy multi-variable cross-section extrusion profile for aerospace and a preparation method thereof. The profile is composed of the following elements in weight percent: Zn 5.0-6.0%, Cu1.0-2.0%, Mn 0.04-0.1% , Mg2.0‑3.0%, Cr0.15‑0.25%, Fe0.35‑0.42%, Si≤0.25%, and the balance is Al. The finished product is obtained after smelting, purification and standing, casting, homogenization treatment, ingot heating, extrusion, pre-finishing, solution treatment, straightening and finishing, deep processing, aging treatment and fine-tuning treatment during preparation. In the present invention, by setting a specific alloy composition and its preparation process, a one-time formed aluminum alloy multi-section extruded profile is obtained, which greatly improves the strength, fatigue resistance toughness, corrosion resistance and stress corrosion resistance of the aluminum alloy profile. It can meet the comprehensive performance requirements of the carrier rocket launcher for multi-section aluminum alloy profiles, break through the current bottleneck of extrusion molding of multi-section profiles, and ensure that its various indicators meet the standards and use requirements. Material guarantee is provided.

The invention discloses an oil removal and heavy metal removal modified walnut shell filter material and a preparation method thereof; the surface of the oil removal and heavy metal removal modified walnut shell filter material is provided with an oxidized graphene coating. The preparation method of the filter material includes the steps that walnut shell powder and oxidized graphene powder are added into a V-shaped mixer simultaneously to be stirred and mixed uniformly, then a cross-linking agent and deionized water are added, cross linking is conducted at the temperature of 50-80 DEG C for 3-3.5 hours, after the liquid phase is filtered out, absolute ethyl alcohol is washed to be neutral, drying is conducted for 1-3 hours at the temperature of 100-140 DEG C, finally a vibration screen is utilized to screen out the filter material with the particle size meeting the requirement, and a finished product is obtained. By means of the filter material, grease and heavy metal in sewage water can be removed simultaneously, the sewage treatment process is greatly simplified, sewage treatment cost is lowered, sewage treatment efficiency is high, the filter material is high in hardness, resistant to wear, good in pressing resistance, not prone to caking, large in toughness, easy to regenerate, long in replacement cycle and low in cost.

The invention relates to a heat-resistant sphere which is prepared from the following components in percentage by weight: 3.00-4.20% of C, 1.8-3.0% of Si, 0.2-1.2 of Mn, 2.0-4.0% of Ni, 0.3-1.0% of Mo, less than or equal to 0.07% of P, less than or equal to 0.02% of S and the balance of Fe. According to the heat-resistant sphere provided by the invention, the fatigue resistance of the material is guaranteed by adding Ni and Mo elements; and moreover, the cold cracking tendency is reduced, the safety coefficient is improved, and the service life is prolonged. The preparation process is further improved, for example, the content of S is strictly controlled, and S is removed in a ladle by using industrial sodium carbonate; a metal-stream inoculation treatment method is adopted; a unique high-medium annealing treatment process and the like are adopted, and the tensile strength, yield strength, ductility and hardness HS of the prepared heat-resistant sphere are greatly improved.

The invention discloses a method used for manufacturing ploughing blade reinforcing ribs of agricultural ploughs. The method comprises the steps of carrying out blanking on steel sheets to form ploughing blade blanks with to-be-upset parts on the edges; heating the to-be-upset parts, on the edges, of the ploughing blade blanks; placing the ploughing blade blanks partially heated into upsetting dies; carrying out upsetting on the heated to-be-upset parts, placed into the upsetting dies, of the ploughing blade blanks through a forging machine so as to thicken the to-be-upset parts; forging and pressing the thickened to-be-upset parts of the ploughing blade blanks so as to form the reinforcing ribs on the ploughing blade blanks. According to the invention, the upsetting dies are simple in structure and convenient to use, blade bodies and the reinforcing ribs of ploughing blade products machined through the upsetting dies can be formed through one steel sheet, machined ploughing blades are high in strength and good in durability, the reinforcing ribs of the ploughing blades are prevented from being separated from the blade bodies, and the production efficiency is improved.

The invention provides soldering flux applicable to quick restoration of cold-punching dies and inserts and a preparation process of the soldering flux. The soldering flux comprises, by weight, 15-20% of aluminum, 1-5% of chromium, 1-5% of manganese, 1-3% of iron and the balance of copper and inevitable impurity. The preparation process of the soldering flux includes steps of continuously casting blank metal bar in the diameter of 3-6 mm in a horizontal or vertical continuous casting manner, and grinding and polishing the blank metal bar so as to be directly used as soldering flux for quickly restoring the cold-punching dies and the inserts. The soldering flux used for quickly restoring the cold-punching dies and the inserts has the advantages of short restoration time, less post-welding defects, good mobility during welding, less deformation and cracking and capability of preventing scratch or drag damage and the like. The cold-punching dies and the inserts after restoration can be further used more than 30,000 times.

The invention discloses a method for electrodepositing a nanocrystalline functional coating on the surface of a porous metal substrate based on anodic oxidation. 2+ -Sn 2+ Sensitization activation, Ni-P electroless plating and pulse electrodeposition nanocrystalline functional coating. The method of the present invention utilizes the electroless Ni-P film as a transition layer, which is beneficial to subsequent electrodeposition of multiple coatings, such as Ni, Cu, and the amorphous structure helps to refine the grain size of the subsequent coating; The aging treatment at low temperature in the method is beneficial to alleviate the growth stress of the Ni-P film and avoids the tendency of cracking; the method of the present invention is applicable to the surface modification of various active metals such as pure titanium, aluminum or magnesium; The Ni‑P thin film is used as a transition layer to electrodeposit a large thickness of nanocrystalline coating. The method of scratch test and cross-section observation is used to verify that the interface bonding force is good, and it can be used as an engineering surface material under general low-load and anti-wear conditions.