29 results about "Shrinkage coefficient" patented technology

The invention relates to a method and device for preventing longitudinal cracks of a slab continuous casting head slab, and belongs to the technical field of continuous casting methods and devices. According to the technical scheme, the method comprises the following steps: calculating a function relational expression between a solidification shrinkage coefficient of molten steel and a casting blank temperature and between a linear expansion coefficient of a blank shell and the casting blank temperature; predicting the temperature of a billet shell and molten steel of the continuous casting billet discharged from the crystallizer; calculating the casting blank width of the continuous casting blank at the lower opening of the crystallizer and the actual casting blank width at high temperature; the ratio of the blank shell width to the lower opening width of the crystallizer is calculated and set according to actual conditions, and when the ratio is smaller than a threshold value, an operation interface gives an alarm for adjustment. The method has the beneficial effects that the longitudinal cracks of the head blank of the continuous casting blank are prevented on line, the flame cleaning work of the casting blank due to the longitudinal cracks is avoided, the time for offline casting blank cooling and manual cold detection is shortened, the temperature loss and turnover time of the casting blank are reduced, and the labor intensity of workers and the production cost loss are reduced.

The invention provides a semi-rigid base top surface early-age transverse cracking stress related strain measurement method and a cracking trend evaluation method. The method comprises the following steps: firstly, obtaining a dry shrinkage coefficient and a temperature shrinkage coefficient of a semi-rigid base material; obtaining the detection range of the construction site, and arranging a plurality of first strain sensors in the detection range along the longitudinal direction and the transverse direction; then manufacturing a semi-rigid base test piece, and arranging a second strain sensor on the top surface of the semi-rigid base test piece; and according to the difference value between the longitudinal strain of the top surface of the semi-rigid base and the longitudinal strain of the top surface of the semi-rigid base test piece, obtaining the early-age transverse cracking stress related strain of the top surface of the semi-rigid base at the construction site, and further obtaining the evaluation of the cracking trend. According to the method, the related strain of the cracking stress of the top surface of the semi-rigid base is accurately and continuously measured at the early age after the semi-rigid base is paved through simple operation, and the probability and trend of generation of transverse cracks at different positions of the top surface of the semi-rigid base are accurately evaluated.

The invention provides a production size control method for a hard alloy roll collar blank and an intelligent production system, and belongs to the technical field of powder metallurgy. The method aims to solve the problems of low finished product qualification rate and high cost caused by uncontrollable sintering shrinkage of the hard alloy roll collar in the prior art. According to the technical scheme, the method comprises the steps that a set of linear shrinkage coefficients of a hard alloy roll collar pressed blank are designed in advance based on the target finished product size, and the target size of the pressed blank is calculated according to the set of linear shrinkage coefficients and the target finished product size; then, according to the calculated target size, wax-doped powder serving as a raw material is subjected to compression molding, and a compressed blank is obtained; and finally, the pressed blank is transferred into a low-pressure sintering furnace for dewaxing and sintering treatment. According to the method, the quantifiable linear shrinkage coefficient is introduced, empirical estimation is converted into accurate calculation, operation is simplified, the accuracy and consistency of the size of a finished product are remarkably improved, and the rejection rate and the production cost are reduced.

The invention discloses an image printing method suitable for multi-level high-fall natural slate, and relates to the technical field of printing, and the method comprises the following steps: S1, rock surface characteristic analysis: the section fall delta h and the edge inclination angle theta of the natural slate are obtained through three-dimensional scanning, delta h represents the vertical height difference of adjacent levels, and theta is the included angle between the edge tangent plane and the horizontal plane; s2, dynamic parameter modeling: on the basis of delta h and theta, a bottom layer shrinkage coefficient C1 and an upper layer expansion coefficient C2 are calculated through RIP control software, C1 is dynamically adjusted to be 0.8-1.2 pixels according to delta h, and C1 = 1.2, delta hlt when delta h is larger than or equal to 8 mm; when the thickness is 8 mm, C1 is equal to 0.8 + 0.05 delta h; c2 is dynamically adjusted to be 1.0-1.5 pixels according to theta, and C2 is equal to 1.0 + 0.03 theta; s3, ink dispersion compensation control: calculating the ink dispersion compensation value of each area according to Cadj = 0.15 delta h + 0.2 tan theta, and dynamically adjusting the ink jet pressure; s4, real-time trapping adjustment is conducted, specifically, when color printing and gold and silver hot stamping are overlapped, the nozzle distance d is monitored in real time, and when d-d0gt is detected; and when the thickness is 0.5 mm, the special image printing technology can adapt to the dynamic structure of slate, the natural texture is reserved, and the limit printing precision is achieved.

This invention relates to the field of PCB manufacturing technology, and more particularly to a method for manufacturing large-size PCBs, comprising: cutting a large-size substrate into several core boards conforming to the dimensions of a PCB; drilling several positioning holes with a first pre-expansion / shrinkage amount in the core boards; determining the position range of the circuit pattern on the core boards according to the positioning holes; determining the range of the rivet hole circuit pattern that coincides with the range of the positioning hole circuit pattern according to the range of the positioning hole circuit pattern; drilling several rivet holes with a second pre-expansion / shrinkage amount in the range of the rivet hole circuit pattern, wherein the first pre-expansion / shrinkage amount is the sum of the etching expansion / shrinkage amount and the pressing expansion / shrinkage amount during the process of cutting and laminating the core board; and the second pre-expansion / shrinkage amount is the etching expansion / shrinkage amount during the process of cutting and etching the core board. This invention can solve the problems of inconsistent expansion / shrinkage coefficients of core boards with different thicknesses or different copper thicknesses due to expansion / shrinkage during the manufacturing of large-size PCBs, and the problems of rivets not fitting or laminating layers being misaligned during lamination and riveting.

The invention discloses a shrinkage coefficient calculation method based on an asphalt mixture core sample, which comprises the following steps: acquiring the asphalt mixture core sample, and cutting the asphalt mixture core sample into a disc test piece; measuring a calibration strain coefficient of the circular asphalt mixture shrinkage coefficient testing device; putting the disc test piece into a circular asphalt mixture shrinkage coefficient testing device, pasting a temperature sensor on the surface of the test piece, putting the testing device into an environment box, then carrying out a shrinkage coefficient test and calculating the shrinkage coefficient. The shrinkage coefficient calculation method based on the asphalt mixture core sample is simple and easy to implement, real and reliable in data and simple to operate, can effectively calculate the shrinkage coefficients of different asphalt mixture core samples, and is a shrinkage coefficient calculation method with relatively high innovativeness.

The invention discloses a thermal deformation detection system and method for a powder metallurgy component, and relates to the technical field of thermal deformation detection, and the method comprises the following steps: filling a detection cavity with inert gas, debugging a resistance furnace, calibrating a temperature control system, clamping a powder metallurgy component sample in the detection cavity, monitoring the internal and surface temperatures of the powder metallurgy component, and adjusting the heating rate. Cooling after heating; measuring coordinates of feature points on three arcs with the standard axis point as the circle center on the sections of the upper end and the lower end of the powder metallurgy component, calculating coordinates of measured axis points of the upper end and the lower end of the powder metallurgy component, calculating the axis point offset distance of the powder metallurgy component, calculating the axis offset angle and calculating the axis offset index; the height difference between the feature points and the standard plane is obtained, the flatness coefficient of the powder metallurgy component is calculated, the expansion and shrinkage coefficient of the powder metallurgy component is calculated, and the surface deformation index of the powder metallurgy component is calculated; and the axis deviation index and the surface deformation index of the powder metallurgy component are obtained, and the thermal deformation index of the powder metallurgy component is calculated.

This application relates to the technical field of evaluating the discharge capacity of a practical weir and discloses a method and apparatus for measuring the lateral shrinkage coefficient of a special-shaped isolated pier of a practical weir. The method includes the steps of obtaining test data for a dam's overflow weir, conducting a model test based on the test data to determine fitting coefficients, obtaining parameters for the special-shaped isolated pier of the practical weir, determining a lateral shrinkage correction coefficient for the special-shaped isolated pier based on the parameters of the special-shaped isolated pier of the practical weir and the fitting coefficients, and calculating a comprehensive lateral shrinkage coefficient for the special-shaped isolated pier of the practical weir based on the parameters of the special-shaped isolated pier of the practical weir and the lateral shrinkage correction coefficient for the special-shaped isolated pier. The comprehensive lateral shrinkage coefficient of the special-shaped isolated pier of the practical weir is used to evaluate the discharge capacity of a practical weir with a special-shaped isolated pier. This application enables accurate measurement of the calculated flow coefficient of a practical weir with a special-shaped isolated pier, laying a foundation for evaluating the discharge capacity of a practical weir with a special-shaped isolated pier.

The present invention discloses a radial shrinking forming method that breaks through the limitation of shrinking coefficient, including a fixing mechanism, a working mechanism and a power mechanism; the fixing mechanism includes a shell, the shell is provided with a feed port and a cavity, the feed port is for the tube blank to be placed and fed along the axial direction of the cavity, the working mechanism includes a plurality of shrinking petal dies, the shrinking petal dies are installed in the cavity and connected to the power mechanism, the plurality of shrinking petal dies are surrounded at equal angles around the outer circumference of the tube blank, the power mechanism drives the shrinking petal dies to reciprocate in a short distance along the normal direction of the cavity, and during the axial feeding of the tube blank, the short-range reciprocating motion of the shrinking petal dies hits the tube blank, causing the tube blank to produce plastic deformation. This case can effectively realize the cold and hot deformation of the tube blank, and is not limited by the shrinking coefficient, and will not cause defects such as instability of the force transmission area, wrinkling of the mouth and height inconsistency; by controlling the frequency of opening and merging of the shrinking petal dies to adapt to materials of different hardness and softness, the process flow is simplified and production efficiency is improved.

The invention relates to the technical field of civil engineering, in particular to a concrete structure random shrinkage creep calculation method which comprises the following steps: acquiring data of a concrete structure needing to be calculated; calculating a creep coefficient and shrinkage strain curve of the concrete structure; a concrete shrinkage and creep calculation model is constructed, and an updated stress-strain relation is obtained; combining a concrete shrinkage creep test database to construct a concrete shrinkage creep randomness coefficient, and finally obtaining a shrinkage creep deformation calculation result priori interval of the concrete structure; establishing a Gaussian process regression model; and performing Bayesian inference by adopting a Monte Carlo-Markov chain method and a Gaussian process regression model to obtain a posterior interval of a concrete structure shrinkage creep calculation result needing to be calculated. The problems that an existing concrete structure is high in shrinkage creep randomness and insufficient in prediction precision are solved. According to the method, Gaussian process regression is adopted, and the problem that a large amount of calculation cost of finite element calculation is needed in Bayesian inference is solved.

The invention belongs to the field of concrete shrinkage, and relates to a steel-concrete combined bridge deck concrete shrinkage parameter testing method which comprises the following steps: S1, manufacturing an equal-proportion test model according to a to-be-built steel-concrete combined bridge deck; s2, actually measured strain force of each strain force measuring point and actually measured displacement of each deflection measuring point in the test model are collected in real time; s3, obtaining the theoretical strain force of each strain force measuring point and the theoretical displacement of each deflection measuring point in the test model; s4, obtaining an actual measurement shrinkage equivalent cooling coefficient based on the actual measurement strain force of each strain force measuring point and the actual measurement displacement of each deflection measuring point in the test model, and the theoretical strain force of each strain force measuring point and the theoretical displacement of each deflection measuring point; and S5, inputting the actually measured shrinkage equivalent cooling coefficient and the concrete shrinkage hyperbolic power function into an Origin model for fitting to obtain a concrete shrinkage coefficient equation parameter and a fitting shrinkage equivalent cooling coefficient curve. The problem that the concrete shrinkage parameter testing result of an existing steel-concrete combined bridge deck is not accurate is solved.

The embodiment of the invention provides a post-lamination dimensional stability control method, system and device and a medium, and the method comprises the steps: respectively constructing a training sample set and an initial model set for different model set factors, and for each initial model set, constructing a training sample set and an initial model set; performing multi-round iterative training on the initial model group by using the corresponding training sample set to obtain a corresponding target model group; the method comprises the following steps: acquiring a model group factor of a product, determining a target model group corresponding to the product according to the model group factor, inputting to-be-processed expansion and contraction change data corresponding to the product into the target model group corresponding to the product, and performing derivative calculation on the to-be-processed expansion and contraction change data through the target model group, and obtaining a predicted expansion and shrinkage range after the PCB is laminated, and adjusting and controlling the expansion and shrinkage coefficient of the product according to the predicted expansion and shrinkage range after the PCB is laminated. The purposes of automatically adjusting and controlling the expansion coefficient and improving the efficiency of adjusting the expansion coefficient are achieved.

This invention relates to the field of spring testing technology, specifically disclosing a spring force testing device and method for spring production, comprising: an environmental parameter acquisition array to acquire temperature, humidity, and vibration distribution; a shrinkage parameter extraction module to extract vibration shrinkage coefficient and vibration shrinkage vector based on vibration distribution; an error coupling analysis module to calculate the non-uniformity of temperature field, humidity field, and vibration field and input it into a multi-field coupling error model to obtain a comprehensive error coupling coefficient; a parameter progressive correction module to progressively correct the original force value and deformation based on the vibration shrinkage coefficient and vibration shrinkage vector to obtain the final corrected force value and deformation; a stiffness progressive calculation module to calculate the initial stiffness coefficient and hysteresis coefficient; a vector composite navigation module to synthesize a composite navigation vector based on stiffness deviation and hysteresis deviation; and a navigation execution module to decompose the composite navigation vector into axial and radial components and perform adjustments. This invention achieves environmental adaptation and multi-parameter collaborative navigation for spring force testing.

The invention discloses a compaction pile hole shrinkage space-time change rule prediction method and system, and relates to the technical field of foundation treatment and geotechnical engineering.The method comprises the steps that data such as the depth of a to-be-measured pile hole is obtained; establishing a function relationship of the peak cohesion, the peak internal friction angle, the residual cohesion and the residual internal friction angle with respect to the water content based on the test data; establishing a softening constitutive relation of the strength evolved from a peak value to a residual value according to the accumulated plastic shear strain; determining far-field lateral stress by combining the depth, the soil weight and the static soil pressure coefficient, and constructing a three-zone stress field of a residual zone, a softening zone and an elastic zone around the pile hole according to the far-field lateral stress; further constructing a system shrinkage coefficient according to the relationship between the stress state at the hole wall and the viscoplastic strain rate, and establishing an evolution equation of the hole radius about time, depth and water content; and calculating a change result of the radius of the pile hole along with time and depth in the target time period according to the evolution equation. According to the method, unified calculation of the shrinkage process under the combined action of multiple factors is realized.

The invention discloses a method for calculating a damp-heat coupling strain and a cracking index of a cement-based material. The method comprises the following steps: firstly, deducing a damp-heat coupling control equation, and establishing a damp-heat coupling strain formula considering steel bar constraint, a concrete creep effect and a structural constraint condition, so as to obtain a calculation method of a cracking index; secondly, key parameters are measured, an engineering concrete finite element model is constructed, an initial value and boundary conditions are input, a partial differential equation is solved through an implicit difference method, and a concrete temperature and humidity coupling field is obtained; and then, through temperature and humidity changes at different time and positions, combining the thermal expansion coefficient and the moisture shrinkage coefficient, calculating actual temperature and humidity coupling strain, and comparing the actual temperature and humidity coupling strain with field monitoring data to verify that the actual temperature and humidity coupling strain is well matched with the field monitoring data. The method is suitable for a concrete structure with an obvious damp-heat coupling effect, such as a large-area long side wall, a pipe piece needing steam curing and water curing, mass concrete containing a cooling water pipe and the like.

The utility model discloses a hard alloy thin plate die which comprises a female die, an upper punch and a lower punch, a central groove of the female die is of a square structure, the opposite faces of the upper punch and the lower punch are planes, the outer sides of the upper punch and the lower punch define a square shape, the square size of the upper punch and the square size of the lower punch are matched with the groove, and the shrinkage coefficient of the female die is designed to be 1.26. The height pressing shrinkage coefficient of the upper punch and the lower punch is designed to be 1.23. According to the utility model, the compact can be ensured to have enough strength and density and is not easy to crack.

The invention relates to the field of PCB manufacturing, in particular to a control method for improving multilayer ultrahigh alignment of a laminated PCB, and the method comprises the following steps: S1, pre-giving an expansion coefficient; s2, pattern transfer; s3, browning and baking the board; s4, fusing and pressing the plate; s5, measuring the expansion and shrinkage coefficient of the core plate by a PL machine; s6, compensating the core board, and giving a formal coefficient; s7, manufacturing a formal plate by using the formal coefficient; in the step S2, pattern transfer is carried out by adopting a multi-time etching method; and a step S34 is added between the step S3 and the step S4, measurement is carried out on each layer of core board before lamination, the steps S2 and S3 are repeated, and the step S4 is continued. By adopting a multi-etching method, the expansion and shrinkage coefficient of each core board after etching can be more accurately controlled, and the coefficient deviation and the alignment degree between the laminated core boards are improved. And by adding the step S34, all the core plates are compensated to be consistent before lamination, so that the relative position of each layer of pattern is optimized, and the alignment deviation caused by overlarge difference of expansion and shrinkage coefficients is reduced.

The embodiment of the present application provides a plywood anchoring method and anchoring structure, which relates to the technical field of plywood anchoring. The plywood anchoring method includes the following steps: S1 placing a polyurethane plate body above the plywood under the insulation box, aligning the polyurethane plate body with the embedded holes of the plywood on the insulation box, embedding and installing the anchor plate in the embedded holes, and fixing the anchor connecting plate to the surface of the plywood on the insulation box by rivets; S2 screwing the intermediate connector assembly into the assembly screw groove opened on the surface of the anchor plate for pre-positioning assembly. This solution avoids the displacement problem caused by single-point fixation by limiting the position of the multi-layer plate. This fixing method uses a through-hole design of the multi-layer plate to avoid cracking at the step in the stepped hole and fixation failure caused by different shrinkage coefficients of different materials.

The invention provides a system and a method for synchronously measuring thermal expansion and chemical shrinkage coefficients of prepreg, and relates to the technical field of composite material attribute characterization, the system comprises: a heating table, which is used for placing a prepreg sample to be measured and providing an experiment temperature required by curing of the prepreg sample; the thermal infrared camera is used for measuring the surface temperature of the prepreg sample in the curing experiment process in real time; the lighting device is used for providing ambient brightness required by a curing experiment; the DIC image acquisition system is used for acquiring a high-resolution image of the prepreg sample in a curing experiment process in real time; and the data processing device is connected with the thermal infrared camera and the DIC image acquisition system, and is used for analyzing the image acquired by the DIC image acquisition system to obtain the strain of the prepreg sample and recording the strain and temperature data. The invention provides a non-contact measurement method based on an indirect volume measurement method, and the strain of the prepreg in the curing process is measured through a digital image correlation (DIC) method.

The embodiment of the invention provides a plywood anchoring method and structure, and relates to the technical field of plywood anchoring. The plywood anchoring method comprises the following steps that S1, a polyurethane plate body is arranged above a lower plywood of an insulation box, the polyurethane plate body is aligned with an embedding hole of an upper plywood of the insulation box, an anchoring plate is embedded and installed in the embedding hole, and an anchoring connecting plate is fixed to the surface of the upper plywood of the insulation box through rivets; and S2, the middle connector assembly is screwed into an assembly screw groove formed in the surface of the anchoring plate for pre-positioning assembly. According to the scheme, the problem of displacement caused by single-point fixation is avoided by limiting and fixing the multiple layers of plates, and the situation that the steps in the stepped holes crack and fixation fails due to different shrinkage coefficients of different materials is avoided due to the through hole design of the multiple layers of plates in the fixing mode.

The invention discloses a radial necking forming device breaking through necking coefficient limitation, and relates to the technical field of light metal material plastic processing, the radial necking forming device comprises a motor and a clutch, and the output end of the motor is in butt joint with the clutch. When the radial necking forming device breaking through the limitation of the necking coefficient is used, cold and hot deformation of the pipe blank can be effectively realized by adopting a mode of feeding the pipe blank and impacting the pipe blank through radial high-frequency reciprocating motion of the sectioning type necking die, the limitation of the necking coefficient is avoided, and the defects of instability of a force transfer area, wrinkling of an opening part, inconsistent height and the like are avoided; and the opening and closing frequency of the necking sectioning die is controlled to adapt to materials with different hardness degrees, so that the technological process is simplified, the production efficiency is improved, the necking coefficient range of one-time forming is expanded, and therefore when the radial necking forming device is used, the effects of breaking through necking coefficient limitation and improving the working efficiency are achieved.

The utility model discloses an asphalt mixture core sample shrinkage coefficient testing device which comprises a base plate, a core sample placing groove is concavely formed in the top surface of the base plate, and a plurality of steel balls are arranged in the core sample placing groove; a displacement sensor is arranged on the base plate and located on the side of the core sample containing groove, and the displacement sensor is used for making contact with the outer side of the core sample in the core sample containing groove. Displacement sensors in multiple directions are arranged to measure the shrinkage of a core sample in different directions in real time, so that the effect of monitoring data in the cooling process of the round core sample in real time is realized, the multidirectional shrinkage coefficient of a test piece can be measured in real time, the influence of anisotropy of an asphalt mixture is considered, and the measurement accuracy is improved. And the problems of poor dial indicator precision and large manual reading error in the existing shrinkage coefficient test are solved.

The application relates to the technical field of PCB production and processing, in particular to a method for designing a PCB milling path, which comprises the following steps: calculating a single-board area and a boundary area by using polygon Boolean operation and inclusion operation according to the drilling position and the plate frame position of a PCB; generating a PCB milling path; adjusting path coordinates according to the milling path and a shrinkage coefficient; reading a milling file, checking milling data, and manually fine-tuning the data; outputting the milling file and converting the file into a format that can be read by numerical control equipment. Compared with the prior art, the method for designing a PCB milling path solves the problems that, in the current PCB milling process, there is a manual cognitive bias when designing a milling path, which leads to low efficiency and quality and excessive human resources, and the method has the advantages of strong universality, the ability to quickly design a reasonable milling path and a tool changing path, the reasonable use of processing time, and the improvement of design efficiency, processing efficiency and quality.

The invention relates to the field of PCBs (printed circuit boards), in particular to a high-alignment multi-layer PCB expansion and shrinkage compensation method, which comprises the following steps of: adding a step S34 between the original steps S3 and S4, performing first measurement on each layer of core board, repeating the steps S2 and S3, and continuing the S4; and step S45 is added between the step S4 and the step S5, second measurement is carried out on each layer of core board, the steps S2-S4 are repeated, and the step S5 is continued. And the step S34 comprises the steps of etching and baking the etched core plates, then measuring the expansion and shrinkage coefficient for the first time, and compensating the core plates to be consistent. And the step S45 comprises the steps of performing browning on each layer of core board after browning, then performing baking, then measuring the expansion and shrinkage coefficient for the second time, and compensating each layer of core board to be consistent. The stability of the PCB is improved through multiple times of baking, and it is guaranteed that follow-up expansion and contraction are not too large. The expansion and shrinkage of each layer of core plate can be continuously corrected through multiple times of measurement, so that the expansion and shrinkage of each layer of core plate can be compensated according to the design copper thickness requirement, the core plates are compensated to be consistent, and the precision of hole positions is improved.

This application discloses a method and system for predicting the spatiotemporal variation law of borehole shrinkage in compaction piles, relating to the fields of foundation treatment and geotechnical engineering. The method includes: acquiring data such as the depth of the pile borehole to be tested; establishing functional relationships between peak cohesion, peak internal friction angle, residual cohesion, and residual internal friction angle with respect to water content based on experimental data; establishing a softening constitutive relationship based on the evolution of strength from peak to residual based on cumulative plastic shear strain; determining the far-field lateral stress by combining depth, soil weight, and at-rest earth pressure coefficient, and constructing a three-zone stress field around the pile borehole comprising a residual zone, a softened zone, and an elastic zone; further constructing a system shrinkage coefficient based on the relationship between the stress state at the borehole wall and the viscoplastic strain rate, and establishing an evolution equation for the borehole radius with respect to time, depth, and water content; and calculating the variation of the pile borehole radius with time and depth within a target time period based on the evolution equation. This method achieves unified calculation of the shrinkage process under the combined action of multiple factors.

The invention belongs to the technical field of water conservancy projects, and particularly relates to a mold for preparing a test piece in a low-temperature crack resistance test of an asphalt concrete panel sealing layer and a test method. The die is provided with a concave cavity with an opening, the inner depth of the concave cavity is 2 mm, and the concave cavity is made of indium steel. When the mold is used for preparing a test piece, the thickness can be accurately controlled to be 2 mm and is consistent with the actual thickness of an asphalt concrete panel sealing layer, and the actual temperature state of the interior and the surface of the sealing layer in actual engineering can be reflected. The sealing layer test piece is made of indium steel, the temperature shrinkage coefficient of the indium steel is far smaller than that of the sealing layer test piece, shrinkage of the sealing layer test piece cannot be affected in the cooling process of the low-temperature crack resistance test, the test piece and a mold can be tested together, and micro cracks caused by initial damage to the test piece due to demolding or moving are avoided. According to the test method, the cracking temperature of the closed layer is obtained according to the temperature-strain relation curve, and the method is more accurate than the method for evaluating the cracking temperature by simply observing cracks by naked eyes.

The invention relates to the technical field of mechanical engineering, and discloses a keyless cooperation equipment disassembly and assembly method based on cooperation of cold contraction and heat expansion of liquid nitrogen, and the method comprises the steps of S1, early-stage general preparation, S2, specific disassembly, S3, specific assembly and S4, key quality control. Multi-point measurement is carried out on the outer diameter of the shaft and the inner hole of the mating part through a micrometer and a dial indicator tool (the measurement section of the outer diameter of the shaft is larger than or equal to 3, and the measurement mode of the inner hole is coaxial with the outer diameter of the shaft), the thermal expansion and cold shrinkage target size is calculated by combining the thermal expansion coefficient and the cold shrinkage coefficient of a part material, and it is ensured that the actual interference magnitude is stabilized within the design range of 0.08 mm-0. 1 mm; disassembly and assembly clamping stagnation or part damage caused by parameter deviation is effectively avoided, and the disassembly and assembly failure rate is reduced to the minimum.

The present invention relates to the technical field of shipbuilding, and more particularly, to a method for compensating the accuracy of the deck of a pure car carrier. The method for compensating the accuracy of the deck of a pure car carrier is as follows: when welding the butt joints of the deck, the welding sequence of the deck is to first weld the upper deck and then weld the lower deck; the width of the butt joints gradually narrows in a stepped manner from the upper deck to the lower deck. The beneficial effects of the embodiments of the present invention are as follows: when welding the butt joints of the deck, welding is carried out from top to bottom. According to the assembly deformation coefficient and welding shrinkage coefficient of the deck, the width of the butt joints decreases in a stepped manner from top to bottom, reducing the influence of the assembly deformation coefficient and welding shrinkage coefficient of the deck on the welding accuracy and ensuring the accuracy of the sub-assembly.

The present application relates to a method for manufacturing a non-magnetic cemented carbide material standard block, comprising the following steps: determining the size of the cylindrical standard block to be prepared and the diameter and depth of the internal nickel pool, measuring the shrinkage coefficient c of the non-magnetic cemented carbide material, calculating the diameter φ3 and height h2 of the cylindrical compact, the diameter φ4 and depth H2 relative to the pressing surface of the paraffin wax ball according to the shrinkage coefficient c of the non-magnetic cemented carbide material, over-pressing the compact obtained in the mold to obtain a blank, and performing precision machining to obtain the non-magnetic cemented carbide material standard block. The method for manufacturing a non-magnetic cemented carbide material standard block provided by the present application utilizes the migration of metallic nickel to the position of the specifically designed paraffin wax ball during the sintering process to form a nickel pool with a specific diameter and / or depth in the standard block. The present application also relates to a non-magnetic cemented carbide material standard block manufactured by the above method and a rapid detection method for the nickel pool in the non-magnetic cemented carbide material.