16 results about "Graphite morphology" patented technology

The invention provides a nodular cast iron material and a preparation method and application thereof. The preparation method of the nodular cast iron material comprises the following steps that S1, a mixture of pig iron, low-manganese waste steel and foundry returns is heated to be completely molten, alloy and auxiliary materials are supplemented and adjusted to target components, and base iron is obtained; s2, a spheroidizing agent is added into the base iron to conduct spheroidizing treatment, ladle-to-ladle inoculation is conducted after spheroidizing treatment, and an efficient inoculant is added during ladle-to-ladle inoculation; s3, pouring is conducted, and during pouring, a long-acting stream inoculant is added for instantaneous inoculation; and S4, carrying out vibration aging treatment to obtain the nodular cast iron material. According to the nodular cast iron material, collaborative upgrading is achieved in the three dimensions of graphite form-matrix strength-thermal stress dissipation, in a bench test, the number of hot cracks is greatly increased, the service life is obviously prolonged, and reliable guarantee is provided for braking safety of heavy vehicles.

The invention relates to a thick and large-section nodular cast iron inoculation method based on a laminated slow-release inoculation block. The method comprises the following treatment steps that S1, raw materials are prepared; s2, the high-purity pig iron, the waste steel and the nodular cast iron foundry returns in the step S1 are put into an electric induction furnace to be smelted; s3, performing carbon and silicon testing on the molten iron subjected to slag removal in the step S2 by using a carbon and silicon analyzer, and adjusting components; s4, carrying out primary spheroidizing inoculation by adopting a pouring method; and S5, after spheroidizing inoculation is completed, molten iron is poured into a sand mold, a laminated slow-release inoculation block is placed in the sand mold for slow-release inoculation, and a thick and large-section spheroidal graphite cast iron casting is formed. The method has the advantages that slow-release inoculation is implemented in the cross gate, and molten iron continuously and slowly releases an inoculant in the pouring process through the laminated slow-release inoculation blocks. By means of the method, inoculation recession can be effectively inhibited, the graphite form is improved, and finally the density and the spheroidization rate of graphite nodules in the center of the thick and large-section nodular iron casting are increased.

The invention discloses a high-carbon-equivalent gray cast iron brake disc and a casting method thereof, and relates to the technical field of cast iron. In the casting process of the high-carbon-equivalent gray cast iron brake disc, a specific amount of the inoculant with proper components and proper granularity is added in a proper adding mode, so that the structure defects of blocky graphite, graphite floating, coarse graphite and the like are avoided, the brake disc has a fine and bent A-type graphite form, and the service life of the brake disc is prolonged. The high thermal conductivity requirement of the brake disc is met, and the thermal fatigue performance of the brake disc is improved.

The present application relates to a kind of graphite morphology and spheroidization rate analysis system and method based on image processing, belong to the technical field of graphite morphology analysis. Including the following steps: S1, obtaining the two-dimensional metallographic image of the measured nodular cast iron;S2, the two-dimensional metallographic image is handled, to separate each graphite particle in image;S3, extract and calculate the multiple shape factor of each graphite particle, the shape factor at least includes roundness, convexity and sharpness;S4, based on the preset determination threshold, whether each graphite particle is qualified spherical graphite is comprehensively judged;S5, based on the area of qualified spherical graphite, the spheroidization rate of the measured nodular cast iron is calculated;S6, output analysis report containing the spheroidization rate. By the present application, the technical problem that single roundness is prone to misjudgment high-risk graphite in the prior art spheroidization rate analysis method is solved.

The invention discloses a low-stress iron alloy casting forming process for a high-strength driving unit shell, relates to the technical field of machine manufacturing, and aims to solve the technical problem that the high-strength state and the low-stress state of the current driving unit shell cannot be balanced after casting. Adding foundry returns into the output raw materials, outputting the foundry returns to an electric furnace for smelting, detecting alloy element states in molten iron, adding stream inoculants and instantaneous inoculants according to the alloy element states, preheating a casting mold, and demolding after cooling is completed, so that casting is completed. According to the method, molten iron added with the composite alloy additive is stirred at a constant speed in the third step, it is guaranteed that alloy elements are evenly distributed in the molten iron, local stress concentration caused by coarse grains can be effectively relieved, meanwhile, the spheroidized graphite form after casting can reduce the cutting effect on a matrix, stress concentration generated at the tip end of graphite is avoided, and the service life of the graphite is prolonged. The casting internal stress is further reduced.

The present application belongs to the field of casting materials, and provides a large volute casting and a preparation method thereof. The present application adopts a ternary synergistic spheroidizing treatment design of yttrium-based heavy rare earth spheroidizing agent, MgO@CaO core-shell structure spheroidizing agent and graphite morphology regulating element. Through step-by-step addition and accurate process control, excellent performance of a graphite spheroidizing rate ≥ 95%, a tensile strength ≥ 500 MPa and an elongation rate ≥ 7% is achieved, a microstructure of spheroidal graphite + ferrite + pearlite and an interface transition layer rich in Ca, Mg, C, O and Y elements are formed, and problems such as insufficient mechanical properties of traditional large volute castings, unstable casting quality of thick sections, formation of chunky graphite and the like are solved, so that the present application has wide application value in the manufacturing of water pumps, fans, compressors and the like.

The invention discloses high-hardness and high-toughness MoCr alloy cast iron for an automobile drawing die and a preparation process thereof.The alloy cast iron comprises, by mass, 3.1%-3.3% of C, 1.6%-1.8% of Si, 0.7%-0.9% of Mn, 0.8%-1.0% of Cr, 0.3%-0.4% of Mo, 0.2%-0.3% of Cu, 0.1%-0.2% of V, 0.05%-0.1% of Nb and the like, the carbon equivalent is controlled to be 3.6%-3.8%, the graphite form is A + B type, and a nanoscale VC + NbC composite dispersion strengthening phase and an epsilon-Cu precipitation phase are dispersed in a matrix; the preparation technology comprises the steps of raw material pretreatment and precise burdening, electric arc furnace smelting and vacuum refining, compound inoculation and A + B type graphite induction, lost foam casting and gradient cooling, double-stage heat treatment and the like, and optional defect repairing. According to the alloy cast iron and the preparation method thereof, through multi-element synergistic strengthening and precise process regulation and control, the tensile strength of the alloy cast iron is larger than or equal to 380 MPa, the impact toughness ak is larger than or equal to 22 J / cm < 2 >, the quenching hardness is 55-58 HRC, the alloy cast iron has high hardness and high toughness, the problem that a traditional material is strong and brittle is solved, the high-frequency stamping requirement of an automobile drawing die is met, the performance is stable, and the industrial adaptability is high.

The present invention relates to a method of controlling graphite morphology in a process of producing graphite, the method comprising: contacting a metal-containing catalyst with a hydrocarbon gas at an elevated temperature to catalytically convert at least a portion of the hydrocarbon gas to hydrogen and carbon; wherein the temperature is between 600 DEG C and 1000 DEG C and the pressure is between 0 bar (g) and 100 bar (g), and wherein both the temperature and the pressure are set within a predetermined range of values to selectively synthesize a graphite material having a desired morphology.

This invention discloses a gradient-strengthened dual high-carbon phase MoCr alloy cast iron and its preparation process, belonging to the technical field of alloy cast iron materials. This alloy cast iron contains 3.0-3.2% C and 1.7-1.9% Si by mass percentage, with a carbon equivalent of 3.7-3.9%. It forms a gradient structure from the surface to the core, consisting of a carbide-rich layer, a transition strengthening layer, and a matrix layer. The carbide content, graphite morphology, and grade of each layer are gradient-adapted, and the mechanical properties meet the requirements of tensile strength ≥390MPa and quenching hardness 56-59HRC. The preparation process includes raw material pretreatment and precise batching, segmented melting and gradient inoculation, directional solidification and gradient cooling, gradient heat treatment and performance regulation, and can also include surface strengthening and defect repair steps. This invention achieves a synergistic improvement in material strength, toughness, wear resistance, and fatigue resistance, completely eliminates the problem of quenching pitting, is compatible with existing production lines, has low raw material costs, and a high casting yield rate, making it suitable for the manufacture of cold stamping and drawing dies for automotive body panels.

The utility model is applicable to the technical field of casting, and provides an automatic weighing and adding device for inoculants, which comprises a mounting frame, and a feeding bin, a mixing bin and a storage bin which are mounted on the mounting frame, the feeding bin, the mixing bin and the storage bin are sequentially communicated, a mixing cavity formed by a structural plate is arranged in the mixing bin, and the structural plate is arranged in the mixing cavity. A mixing cavity is formed in the mixing bin, a discharging cavity is formed in the bottom of the mixing cavity, a mixing assembly is arranged in the mixing cavity, a discharging assembly is arranged at the bottom of the mixing cavity, and the mixing assembly comprises a mixing shaft rotationally installed on the mixing bin and a stirring rod arranged on the mixing shaft in a sleeving mode. The device solves the problems of casting mechanical property difference and abnormal graphite form caused by insufficient mixing of the inoculants, and achieves the effects that different types of inoculants are automatically weighed, fully and uniformly mixed and then added into casting equipment, and the influence on the casting performance due to insufficient mixing of the inoculants is avoided.

The invention relates to the technical field of cast iron materials, in particular to a silicon carbide pre-inoculation synthetic cast iron material system, which comprises a smelting module, a pre-inoculation module, a silicon carbide pre-inoculation module, a silicon carbide pre-inoculation module and a silicon carbide pre-inoculation module, the inoculation module is connected with the smelting module and comprises a first inoculation device and a second inoculation device; the detection module is connected with the smelting module and the inoculation module and used for monitoring the carbon equivalent in the smelting process in real time, collecting a plurality of metallographic samples at different point positions on the casting and conducting metallographic analysis to obtain the graphite form characteristic value and the white body content. And the control module is connected with the smelting module, the inoculation module and the detection module and used for dynamically adjusting the input amount of silicon carbide according to the real-time carbon equivalent in the smelting process and judging the inoculation qualification according to the graphite form characteristic value. The intelligent level and the quality controllability of cast iron production are improved.

The invention discloses a low-stress iron alloy casting forming process for a high-strength driving unit shell, relates to the technical field of machine manufacturing, and aims to solve the technical problem that the high-strength state and the low-stress state of the current driving unit shell cannot be balanced after casting. Adding foundry returns into the output raw materials, outputting the foundry returns to an electric furnace for smelting, detecting alloy element states in molten iron, adding stream inoculants and instantaneous inoculants according to the alloy element states, preheating a casting mold, and demolding after cooling is completed, so that casting is completed. According to the method, molten iron added with the composite alloy additive is stirred at a constant speed in the third step, it is guaranteed that alloy elements are evenly distributed in the molten iron, local stress concentration caused by coarse grains can be effectively relieved, meanwhile, the spheroidized graphite form after casting can reduce the cutting effect on a matrix, stress concentration generated at the tip end of graphite is avoided, and the service life of the graphite is prolonged. The casting internal stress is further reduced.

The application discloses a production method of a nodular cast iron cylinder body and belongs to the technical field of nodular cast iron. In the application, spheroidizing agents are added into molten iron to form spherical graphite morphology of carbon separated out in the solidification process of the molten iron. The graphite nucleation and spheroidization recession can be promoted and the spheroidization effect can be improved through twice inoculation and stream inoculation treatment processes. Silicon has two important functions, i.e. solid solution strengthening and matrix ferritization. Through high-concentration solid solution strengthening, silicon can enhance the strength of the alloy, improve the uniformity of the alloy and reduce the weight. Solid solution strengthening can change the crystal structure, and the solute atoms dissolved in the solid can cause lattice distortion, which increases the resistance of dislocation movement, makes the sliding difficult, and thus the strength and hardness of the nodular cast iron are improved.

The invention relates to a graphite form and spheroidization rate analysis system and method based on image processing, and belongs to the technical field of graphite form analysis. Comprising the following steps: S1, obtaining a two-dimensional metallographic image of nodular cast iron to be detected; s2, processing the two-dimensional metallographic image so as to segment each graphite particle in the image; s3, extracting and calculating a plurality of shape factors of each graphite particle, wherein the shape factors at least comprise roundness, convexity and sharpness; s4, comprehensively judging whether each graphite particle is qualified spherical graphite or not based on a preset judgment threshold value; s5, calculating the spheroidization rate of the to-be-measured nodular cast iron based on the area of the qualified spherical graphite; and S6, outputting an analysis report containing the spheroidization rate. According to the method, the technical problem that high-risk graphite is easily misjudged due to the fact that an existing spheroidization rate analysis method depends on single roundness is solved.

The invention belongs to the field of casting materials, and provides a large volute casting and a preparation method thereof.According to the large volute casting and the preparation method thereof, a yttrium-based heavy rare earth nodulizer, an MgO-CaO core-shell structure nodulizer and a graphite form regulating and controlling element are adopted for ternary cooperative nodulizing treatment design, and through step-by-step adding and accurate process control, the large volute casting is obtained; the excellent performance that the graphite spheroidization rate is larger than or equal to 95%, the tensile strength is larger than or equal to 500 MPa, and the elongation is larger than or equal to 7% is achieved, a spheroidal graphite + ferrite + pearlite microstructure and an interface transition layer rich in Ca, Mg, C, O and Y elements are formed, and the problems that a traditional large volute casting is insufficient in mechanical performance, the casting quality of a thick and large section is unstable, and fragment-shaped graphite is formed are solved. And wide application value is achieved in manufacturing of equipment such as water pumps, fans and compressors.

On the premise that the corrosion resistance and strength of the nodular cast iron are guaranteed, the corrosion resistance is improved by optimizing the alloy element adding amount and the process and utilizing the solid solution strengthening effect of silicon, meanwhile, generation of carbides is reduced through the low nickel-chromium using amount, toughness reduction is reduced, and the service life of the nodular cast iron is prolonged. By combining multi-stage inoculation and process control, it is guaranteed that graphite spheroidizing is sufficient and stable, poor spheroidizing is reduced, the matrix structure is refined, the graphite form is optimized, cooperation of low alloy, high corrosion resistance and high toughness is achieved, the casting strength and toughness are improved, the requirements for corrosion resistance, strength and toughness are met, and the method is suitable for the high-requirement corrosion environment.