33results about How to "Eliminate tensile stress" patented technology

A ram type blowout preventer includes variable ram packers for sealing about tubulars of different outside diameters in the bore of the preventer housing or about a single tubular having a variable outside diameter. Each ram packer includes a body of elastomeric material formed about vertical ribs to conform to tubular having variable OD within a certain range.

A shoe sole with a footbed (5) is described which forms a flexible foot support. In order to provide advantageous constructive conditions it is proposed that the foot support consists of a flat structure (4) receiving tensile forces which is held in a freely suspended manner in a frame (1) defining the edge contour of the footbed (5).

The extrusion apparatus for preparing superfine crystal block material has one structure comprising a die holder, a connecting seat, a conic die case, a conic die core, a wedged extruding rod with reduced extrusion force to avoid cracking of the block, a turning unit, a square vertical channel, a square horizontal channel and a product outlet. The product has high crystal grain fining and smooth surface, and the extrusion apparatus has simple structure, excellent mechanical performance, easy installation and use, and no pollution.

The invention discloses a heating unit for a bottom surface and a conical surface of an engine valve cap part and an application method, belongs to a heat treating device, and particularly relates to a heating source taking oxyacetylene flame as a heat source. The heating unit is characterized by mainly comprising a heater arranged on a rack and a valve fastening and a rotating device, wherein the heater is an oxyacetylene burner nozzle fixed on a burner nozzle support; and the valve fastening and the rotating device is composed of a sleeve which is arranged on a turnplate and can automatically rotate and rotate along with the turnplate, a sleeve self-rotating driving device and a turnplate rotating driving device. The heating unit provided by the invention has the beneficial effects that the heating unit can rapidly and conveniently heat the bottom surface and the conical surface subjected to overlaying, of the valve cap part and conveniently control heating time and temperature, the volume of equipment is small so as facilitate connection with a next step process, and the equipment is conveniently used for eliminating tension stress generated by overlaying of the valve.

A method for fabricating a semiconductor device, in which a lifting phenomenon can be prevented from occurring in forming an amorphous carbon film on an etched layer having tensile stress. According to the invention, since a compression stress on the etched layer or the amorphous carbon film can be reduced or a compression stress film is formed between the etched layer or the amorphous carbon film to prevent a lifting phenomenon from occurring and thus another pattern can be formed to fabricate a highly integrated semiconductor device.

The invention discloses a nickel plating process for an optical mold core, which comprises the following operation steps: cleaning and activation, impact nickel pretreatment, chemical nickel plating and heat treatment. The optical mold core is pretreated by multiple degreasing and activation to avoid the impact of impurities on the surface of the optical mold core on the nickel layer; the surface of the optical mold core is pretreated by impact nickel plating to prevent the chromium contained in the optical mold core material The influence of corrosion-resistant metals such as molybdenum and molybdenum on nickel plating can improve the bonding force between the nickel layer and the substrate; the use of a special electroless nickel plating solution makes the uniformity of the grains formed by the nickel layer and the deposition rate of the coating more ideal, and the obtained High-thickness nickel layer; finally, heat treatment is used to eliminate the compressive stress and tensile stress of the nickel layer, and further make hydrogen gas escape, so as to obtain a high-quality nickel layer without cracking and peeling.

The invention relates to a technical method for composite casting of ceramic and a titanium alloy through assistance of variable-frequency ultrasonic waves. The method aims to solve the problem that the ceramic is fragile, and can reduce the stress of the ceramic and avoid cracking of the ceramic. An ultrasonic solidification technology can enable molten titanium alloy to be well combined with a ceramic matrix, the variable-frequency ultrasonic waves assist in the casting process, so that segregation of the titanium alloy in the solidification process is reduced in the casting process, a finegrained area is enlarged, and formation of developed dendritic crystals is reduced; and the ceramic matrix is coated with the molten titanium alloy, so that the crack resistance of the ceramic material is improved. The molten titanium alloy is prepared by adopting a non-consumable vacuum smelting furnace, wherein a titanium alloy bar is made into consumable electrodes, electric arc heat is generated through discharge between the electrodes under the vacuum condition, and the titanium alloy bar is rapidly heated to a high temperature and then melted to obtain the molten titanium alloy. In the casting and cooling process of the molten titanium alloy, due to solidification and shrinkage of the molten titanium alloy, a pressure stress is applied to the surface of the ceramic matrix, and therefore cracks cannot be easily generated in the using process of the ceramic, and the material integrating the advantages of the ceramic and the titanium alloy is obtained.

The invention relates to a subzero treatment method of a hard alloy for a cold heading mold. Subzero treatment and tempering treatment are performed in sequence for the sintered hard alloy for the cold heading mold; the subzero treatment comprises the following three stages of cooling and insulation treatment after cooling: the temperature is firstly reduced to -75 to -85 DEG C, then is reduced to -135 to -145 DEG C, and is finally reduced to -186 to -196 DEG C; and the tempering treatment comprises the following two stages of heating and insulation treatment after heating: the temperature is firstly heated up to 95-105 DEG C, and then is heated up to 180-240 DEG C. The method enables part face-centered cubic (fcc) cobalt in the alloy to be converted to hexagonal close-packed (hcp) cobalt, improves the wear resistance and the comprehensive performance of the alloy, eliminates the tensile stress in the alloy, and prolongs the service life.

The invention provides a method for manufacturing a pre-deformation line diamond line saw through powder metallurgy, comprising the following steps: basic line manufacturing: selecting metal wires, stranding at least two metal wires into a line, and deforming the stranded line by a deformer to obtain a pre-deformation base line; powder preparation: weighing metal powder, a binder and diamond by mass percent, and adding the mixture into a blender mixer to evenly mixing; line blank manufacturing: putting the base line and powder into a mould, and taking the pre-deformation base line as a centerto prepare a line blank by using a forming technology; and line saw manufacturing: putting the line blank to a sintering furnace for sintering, and cooling with the furnace to obtain the line saw. The manufacturing method provided by the invention has the advantages of simple process, low cost and high production efficiency. The produced line saw has excellent performance, high strength, good flexibility, high hold to diamonds, stable cutting performance, good chip discharging performance and long service life, and is not easy to crack.

The invention discloses a prefabricated and assembled lattice type composite floor slab and a construction method thereof, belonging to the technical field of prefabricated and assembled buildings. The prefabricated assembled lattice type composite floor is assembled by a plurality of prefabricated slab units. Intercostal grid; the sides of the rib beams that constitute the intercostal grid are provided with upper, middle, and lower planes, and the lower parts of the upper and lower planes extend toward the intercostal grid to form inclined surfaces. The surface is connected with the surface of the upper and lower regions, and the intercostal cells are correspondingly filled with intercostal cell filling materials. Adopting the technical scheme of the present invention can effectively satisfy its heat insulation and sound insulation performance on the basis of ensuring the bearing capacity of the floor slab, and at the same time can better control the thickness of the floor slab. Continuous performance improvement conditions, strong practicability.