36results about How to "Prevent gestational decline" patented technology

The invention belongs to the field of casting technologies and new materials and particularly relates to a high-strength high-tenacity cast-state QT700-10 and a production method thereof. Compared with ductile iron produced in the prior art, the high-strength high-tenacity cast-state QT700-10 has high strength and a high elongation rate, heat treatment is not needed, heavy metal, such as, Ni and Mo are not added in production, the tensile strength Rm in the cast state is larger than or equal to 700 MPa, the elongation rate A is larger than or equal to 10%, compared with the standard brand QT 450-10, the lowest tensile strength is improved by 55% under the same elongation rate; and compared with the standard brand QT 700-2, the lowest elongation rate is improved by four times under the same tensile strength. The high-strength high-tenacity cast-state QT700-10 can meet requirements of automobile ductile iron castings with high requirements for safety and comprehensive mechanical properties.

The present invention discloses an inoculant for increasing the strength of gray cast iron, a preparation method and a use method thereof, and belongs to the technical field of casting. According to the present invention, nitrogen is adopted as an alloy element so as to significantly refine graphite, change graphite morphology, reduce structure wall thickness sensitivity and significantly increase the pearlite content, such that the tensile strength of the gray cast iron is improved, and especially the significant effects are provided for the high-carbon equivalent gray cast iron or high-carbon gray cast iron; the chemical components of the inoculant comprise, by weight, 25-35% of Si, 10-20% of Mn, 10-20% of Cr, less than 0.1% of C, 1-5% of Ca, 1-6% of Ba, 1-6% of N, less than 0.05% of P, less than 0.02% of S, and the balance of Fe; and for the original hot metal having the same components, compared with the ferrosilicon inoculants, the tensile strength of the gray cast iron can be improved by 30-80 MPa with the inoculant of the present invention.

The invention discloses a high-performance magnesium alloy parison continuous casting production line and relates to the technical fields of vacuum magnesium alloy metallurgy and material preparation. The production line is used for producing high-strength deformation magnesium alloy parison materials by whole-course vacuum protection. Equipment for the production line is provided with two vertical melting furnaces used for melting magnesium medium alloy or working alloy, wherein each melting furnace is divided into the two following parts in space: a hermetic melting chamber and a hermetic furnace body; and the pressure of the furnace body is lower than that of the melting chamber so as to form a vacuum barrier and double vacuum protection melting. Feeding cabins are arranged above furnace covers of the melting furnaces, and the opening and closing of doors of the cabins is matched with the conversion of pressure in the cabins so as to eradicate oxidization and burning of magnesium during feeding materials into hot furnaces. A heat insulation and homogenization furnace is arranged between the two melting furnaces to mix liquid coming from the melting furnaces and prepare magnesium alloy containing target components, and then the heat insulation and homogenization furnace stand still to preserve heat. An inoculation agent and leavening agent flowing addition mechanism is arranged on a gap bridge so as to effectively increase cores and prevent recession. Magnetic stirring is carried out in a crystallization process to control the pressing force and the traction speed of a tractor in real time. The equipment has compact structure, safe production and no pollution.

The invention discloses pipe die powder for centrifugally casting a nodular cast iron pipe and a preparation process thereof. The pipe die powder comprises the following components in percent by mass: 60-65 percent of Si, 1.5-2.0 percent of Ca, 2.0-3.0 percent of Ba, 1.4-1.6 percent of Mn, 1.0-1.5 percent of Mg, 1.0-2.0 percent of Zr, 0.7-1.5 percent of Al and the balance of Fe; and the granularities of pipe die powder comprise less than 1.5 percent of 80 mu, 25-30 percent of 100-120 mu, 40-50 percent of 140-180 mu, 25-30 percent of 200-300 mu and less than 2.5 percent of more than 300 mu. The preparation process comprises the following steps of: preparing, melting, pouring, cooling, crushing, milling, proportioning granularities and packaging in vacuum. The pipe die powder has the advantages of uniform components, consistent melting points and reasonable granulometric class, and is beneficial to the prolonging of the service life of a pipe die of the nodular cast iron pipe, the reduction of a series of casting defects of cockles, poor nodulizing, surface cracks and the like of the nodular cast iron pipe, the improvement of the quality of the nodular cast iron pipe and the yield, and the lowering of the production cost.

The invention provides an inoculation line formula for gray cast iron feeding and inoculation and a production process. The inoculation line formula comprises elements: 2.0-2.5% of magnesium, 50-58% of silicon, 1-3% of rare earth, 2.0-3.5% of barium, less than or equal to 1.5% of calcium, less than or equal to 2% of aluminum, and the balance iron. The production process of the inoculation line formula comprises the steps of selecting raw materials including, by mass, 60-65% of steel scraps, 30-35% of recirculated iron and 5-10% of pig iron to be proportioned; smelting and controlling the material compositions; and conducting feeding and inoculation through the inoculation line formula after pre-burying 0.15-0.2% of ferrosilicon to conduct inoculation on molten iron for the first time. Through rational chemical composition control, the actions of all the elements under different environments are given full play to, so that the tensile strength of a produced gray cast iron material is greater than or equal to 330 MPa, and the yield strength is greater than or equal to 220 MPa. As the inoculation line contains rare earth, the inoculation effect is enhanced, inoculation fade is effectively prevented, and inoculation is uniform. After gray cast iron casting through the inoculation line formula, the obtained gray cast iron is excellent in performance, small in hardness drop and highin stability.

The invention discloses a die cavity structure of a back box body casing of a wind power generating unit and a method. The structure comprises a casting system, a back box body die cavity and an air outlet opening, wherein the air outlet opening is formed in the back box body die cavity; the casting system comprises a sprue and a cross pouring gate communicating with the sprue; the cross pouring gate sequentially communicates with a first transition pouring gate, a second transition pouring gate, a third transition pouring gate and a fourth transition pouring gate; the fourth transition pouring gate communicates with the back box body die cavity through a flow gate; a first buffer pouring gate is arranged on the cross pouring gate; the ratio of the cross section area of the first buffer pouring gate to the cross section area of the sprue is 1:(0.60 to0.75). The die cavity structure has the advantages that the iron liquid mold filling instability and turbulence generated by the metal liquid in the casting process can be reduced; the quality stability of the casting can be improved; the slag inclusion defects and air hole defects are reduced; the high-quality requirements can be met.

The preparation method comprises the following steps: uniformly mixing 66-72%% of Si, 3-10% of Ba, 1-2% of Ca, 0.8-1.8% of Al, 1.5-2% of Ce, 0-1% of S, 0.5-1% of a carburant and the balance of Fe and inevitable trace elements to obtain a mixture; smelting, cooling, pouring, quenching and crushing the mixture; mixing the mixture with Fe3O4 powder; and pressing, clustering and crushing the mixture and the Fe3O4 powder. The invention further discloses an application of the inoculant for nodular cast iron. The inoculant for for nodular cast iron provided by the invention can be adopted to improve comprehensive properties of the for nodular cast iron, and improves inoculation efficiency.

The invention provides a molten iron inoculation process for cast iron. A method adopted by molten iron inoculation process comprises the following steps: a dam-type ductile iron ladle is adopted for spheroidization, and an inoculant of which the weight accounts for 0.3-0.5% of that of molten iron is added into the spheroidized ladle; an intermediate ladle is inoculated, that is, the inoculant of which the weight accounts for 0.1-0.3% of that of the molten iron is added into the intermediate ladle, and the treated molten iron is passed into the next step after the inoculant is completely molten; and the molten iron treated in the previous step is added into a pouring ladle, and the inoculant of which the weight accounts for 0.05-0.35% of that of the molten iron is added. According to the molten iron inoculation process, the dam-type ductile iron ladle is adopted for spheroidization, thereby effectively preventing an inoculation fading phenomenon and overcoming a defect of white cast iron; the intermediate ladle is adopted for inoculation, thereby achieving long-acting inoculation of the molten iron; and accordingly, the tensile strength and the product stability can be improved, and the requirements for several high-hardness machinery castings can be met.

The invention discloses a production method capable of eliminating shrinkage cavities and shrinkage porosity for light calliper body castings. An adjusting iron solution is prepared from, by mass, 3.7%-3.9% of C, 1.9%-2.1% of Si, 0.2%-0.4% of Mn, smaller than or equal to 0.02% of S, smaller than or equal to 0.02% of P and the balance Fe. According to the production method, the carbon content in molten iron is increased by adding a graphitized carburant, and the silicon content in the molten iron is decreased by decreasing the addition amount of silicon iron; a strong inoculant is adopted for secondary inoculation, fast pouring is conducted for avoiding inoculation fade, carbon and high silicon in the molten iron are low, the content of phosphorus is also controlled to be low, good fluidity of the molten iron is guaranteed, castability is good, molten iron expansion is small, the strong inoculant promotes graphitization, automatic shrinkage compensation performance is good, the overall shrinkage compensation effect is good, and the weight of the calliper body castings is decreased; and meanwhile, hot-spot portions of the casting can be prevented from being subjected to shrinkage cavities and shrinkage cavity, the rejection rate of the castings is decreased, and the production cost of the castings is reduced.

The invention discloses a composite covering agent and a use method thereof in the production of a cylinder cover casting. The composite covering agent consists of a composite covering agent I and a composite covering agent II, wherein the composite covering agent I consists of the following components in parts by mass: 80-90 parts of SiC, 5-6 parts of recarbonizer and 5-15 parts of perlite; and the composite covering agent II consists of the components in parts by mass: 35-45 parts of inoculant and 55-65 parts of perlite. In the invention, the composite covering agents are adopted in the production of the cylinder cover casting to remove impurities and gas out of iron liquid so as to improve the metallurgical quality of the iron liquid; when heat preservation and collecting residues are carried out, the inoculation fade of the iron liquid is prevented, a favorable inoculation effect is obtained, thereby processing properties and mechanical properties of the cylinder cover are improved; meanwhile, a fine powder inoculant is turned into valuable materials and complies with the policies of recycling economy and low carbon economy. The invention has simple prescription, wide source materials which are easily obtained, simple use method, easy implementation, low production cost and favorable use effect.