5 results about "Metallography" patented technology

The invention relates to the field of metal materials, and discloses a universal high-efficiency metallographic preparation method for metal materials, which comprises the following steps of: (a) roughing a metal sample by using abrasive paper or a grinding disc; (b) finely grinding the metal sample by using a POS / POH (Poly Olefin Sulfonate / Poly Olefin Hydroxide) disc matched with a 9-micron (c) roughly polishing the sample by using weaving type polishing cloth matched with a grinding material with the particle size of 1-3 microns; and (d) finely polishing the metal sample by using polishing cloth matched with a 50nm-1mu m grinding material. The grinding pass can be reduced, the process is greatly shortened, the sample preparation efficiency is improved, batch sample preparation can be realized by matching with automatic equipment, and batch characterization is possible; the usage amount of abrasive paper can be greatly reduced, resources are saved, cost is reduced, and efficiency is improved; and the method has general applicability to metal material samples, and the high-quality metallographic sample can be prepared by only replacing suitable consumables according to the physicochemical properties of metal through four steps.

The invention discloses a welding joint micro-area fatigue performance testing method, and belongs to the technical field of material fatigue performance testing. The method comprises the following steps: firstly, determining a micro-area microstructure of a welding joint through metallographic phase or electron back scattering diffraction, measuring the length and width of the micro-area, then carrying out a micro-area mechanical property auxiliary test, obtaining hardness and residual stress distribution, and determining whether the micro-area is reasonably divided or not; preparing a fatigue sample which is completely positioned in the micro region; performing cyclic loading on the sample, and synchronously recording mechanical response and fatigue life data; establishing a corresponding relation between macroscopic stress and micro-area stress based on test data, and drawing a micro-area S-N curve; and finally, integrating the micro-area fatigue performance and initial performance distribution, and analyzing a multi-scale correlation mechanism among microstructure evolution, micro-area performance and macroscopic failure. According to the method, the fatigue performance of the local weak area of the welding joint is accurately represented, the limitation of traditional macroscopic overall evaluation is broken through, and a new method is provided for service life prediction and process optimization of a welding structure.

The application discloses a CrMoTa series refractory high-entropy alloy metallographic etching liquid and a preparation method thereof, and belongs to the technical field of preparation and detection of refractory high-entropy alloy metallography. According to mass percentage, the metallographic etching liquid contains 16.6-25.4wt% nitric acid, 8.3-12.0wt% hydrofluoric acid, 20-22wt% polyethylene glycol, 0.1-5wt% special additives, and the rest is deionized water. The preparation method is that the deionized water, polyethylene glycol, nitric acid, hydrofluoric acid and special additives are added into a container and stirred uniformly to obtain the etching liquid. The etching liquid can destroy the dense passivation film on the surface of the alloy through the coordination of hydrofluoric acid and the oxidation of nitric acid, can clearly show the grain boundary and grain structure, and solves the problem that the traditional etching liquid cannot effectively etch the alloy with high content of tantalum and molybdenum. The method is simple in operation, low in cost, low in requirement for equipment, good in etching effect, and suitable for rapid metallographic detection of the CrMoTa series refractory high-entropy alloy.

The invention provides an oil and gas pipeline welded joint metallographic determination method and device based on transfer learning, and can be applied to the field of gasoline pipeline maintenance. Based on the method, before specific implementation, according to a preset training rule, a small number of sample metallographic images about the oil and gas pipeline are utilized, a conventional visual image library is combined, and through transfer learning, the oil and gas pipeline can be trained at a relatively low training cost. And training to obtain a preset oil and gas pipeline welded joint metallographic recognition model which is suitable for an oil and gas pipeline maintenance scene and has a relatively good effect. During specific implementation, the preset oil and gas pipeline welded joint metallographic phase identification model can be utilized to identify and determine the metallographic phase type of the target oil and gas pipeline welded joint by processing a target image which is acquired on an oil and gas production and transportation site and at least comprises the welded joint of the target oil and gas pipeline and an adjacent area of the welded joint. Therefore, the method can be well adapted to an oil and gas pipeline maintenance scene, and the metallographic phase type can be efficiently and accurately identified with low data processing cost.

The application provides a carbonitriding process for GCr15 parts, and steps are as follows: pre-oxidation, strong penetration, diffusion, quenching, hot cleaning, cold cleaning, cold treatment, tempering, taking out GCr15 parts, and air cooling after discharging. The application realizes continuous production by using a continuous mesh belt furnace production line with controllable atmosphere for carbonitriding, improves production efficiency, reduces labor intensity of workers, increases production capacity, reduces gap furnace opening and closing actions, reduces energy consumption, and saves at least 50% of cost compared with ordinary carbonitriding. In addition, carbon potential of each zone in the furnace can be controlled, so that quality stability is ensured. The surface hardness of the GCr15 parts obtained by the heat treatment process of the application can reach 62-65HRC, the core hardness is 61-64HRC, the carbide layer is less than 0.02mm, the carbonitriding layer is greater than 0.4mm, the surface carbon content is 1.15-1.5%, and the carbonitriding metallography can reach level 1.