The method for determining the propensity of rolled metal to layered destruction

 

(57) Abstract:

Use: in testing equipment, tensile testing. Essence: in the sample is cut in the thickness direction of the car, creating tension and reduce cyclic load method of heating-cooling insert installed sequentially aligned sample and rigidly bonded with him. The strength of the material of the insert exceeds the strength of the material sample. 1 C. p. F.-ly, 1 Il.

The invention relates to the study of physical-mechanical properties of rolled metals, namely the anisotropy of plasticity and viscosity, which causes formation during welding of layered cracks.

Known mechanical methods of determining the propensity to hire layered destruction with the application of load in the thickness direction of the car. They include the application of tensile force to the core samples cut perpendicular to the plane of the Bicycle.

You know the drop test bending or methods of fracture mechanics specimens with a notch or induced crack located in the plane of the Bicycle, the test for static bending of flat samples cut in the thickness direction crosswise to the direction of p is the preliminary plastic deformation in the thickness direction of the car.

The disadvantage of the methods of mechanical tests is that they do not reflect the possible effects on the propensity to layered destruction effects of thermal and deformation cycles welding, and other related welding factors. Under the influence of heat and power effects of welding individually change the microstructure and mechanical properties of the metal, it is saturated with hydrogen, it flow deformation and thermal ageing. All this cannot but affect the reliability of determination of the inclination of the base metal to the formation of layered cracks.

Also known testing methods, in which the layered destruction occurs in the samples under the influence of its own stresses welding is initiated or tensile stresses from external forces applied to the sample during the welding process or after its completion.

In these methods, the criterion penchant for layered destruction rental is the presence or absence of cracks, and the value of the critical voltage, causing the formation of cracks.

However, these methods are characterized by great intensity, complexity and cost and give qualitative rather than quantitative assessment of p the market and stresses in the cross section of the connection, high speed changes in these characteristics over time make it difficult to separate the study of the role of individual factors in the formation of cracks and their conditions of occurrence.

The closest technical solution of the invention is a method for determining the propensity of rolled metal to layered destruction during welding by testing a sample of the metal to the efforts of the compression-tension in terms of simulated thermal deformation cycles. Quality steel are the maximum stress and strain endured by the sample at the destruction.

A significant drawback is the unreliability of the test results due to inconsistencies simple stretching deformation of the welding cycle. When welding each element of the metal compound sequentially undergoes compression due to local heating and stretching during cooling. When the multilayer welding (which mainly explains the appearance of layered cracks) deformation cycles periodically repeated.

The purpose of the invention is to increase the reliability of test results.

This is achieved by the fact that the efforts applied to the sample using thermal expansion coaxially located with the sample rod will westerhout heating and cooling in thermal cycle of welding, and the test specimen cut out from a rolled in the direction of its thickness and provide test specified constant or variable heat treatment of the sample, and on the resistance of the layered destruction judged by the number of cycles of compression-tension and the total plastic deformation, leading to destruction of the sample.

In addition, the core insert perform with strength greater than the strength of the test sample.

The drawing shows a circuit implementing the method.

The method is implemented in the following sequence.

The test sample 1 is cut out from a rolled in the direction of its thickness and feature between the rigid grip 2 and the connecting yoke 3, which is on the opposite side coaxially with the sample will montirat hard core box 4, which has greater strength properties than the test sample 1. When this box 4 teploizolirovat from sample to create a test independent of temperature regimes.

The free end of the rod inserts are also rigidly fixed to the grip 5. After that, the paste is subjected to heating and cooling in thermal cycle of welding, and the person concerned about the Denia rod insert 4 on the test sample is passed through the ferrule 3 cyclic mechanical load. Warm the insert 4 and its thermal expansion initially cause compression of the sample. With increasing heating temperature and a sharp decline in the material of the insert is plastic deformation of compression, which causes a slight increase in the diameter of the insert and to a reduction of finite length. Upon further cooling, the paste due to the "defect length in the system to insert the sample occurs tensile stress exceeding the yield strength of the sample and causing his plastic elongation.

Repeated heating and cooling of the insert 4 excite the sample 1 repeated cycles of compression-tension, which is accompanied by accumulation (summation) of the deformation characteristic of the multi-layer welding.

The criterion of quality material in this test is the number of cycles to failure of the sample and the maximum total plastic deformation.

Before testing the sample by using the heat treatment can be created with different microstructure corresponding to one of the characteristic zones of the welded connection (high holidays, complete or incomplete recrystallization, overheating).

The temperature of the sample 1 when the test can p the RCTs.

The heating rate and the cooling rod insert 4 can be varied within wide limits.

This allows using the proposed method separate study of the effect on the propensity to layered destruction hire various metallurgical and technological factors with a high degree of accuracy. (56) Jombardini I Einflub des Terrasseubruches Sehweiftechnik, 1978, N 9, p. 168-174.

1. The method for determining the propensity of rolled metal to layered destruction, namely, that the metal sample is exposed to cyclic loads efforts compression, and penchant for layered destruction judged by the number of cycles to failure, characterized in that, in order to bring credibility by bringing to the conditions of thermal deformation cycles welding, coaxially with the sample and consistently with him install the insert, opposite ends of which are rigidly interconnected and available rigidly fixed in the clamps, the effects of cyclic load perform cyclic heating - cooling insert and the sample cut out from a rolled in the direction of its thickness.

2. The method according to p. 1, characterized in that the insert is made of a material whose strength exceeds strongly the

 

Same patents:

FIELD: testing engineering.

SUBSTANCE: device comprises high-frequency generator and inductor connected in series, device for control of heating, system for air supply, device for external cooling, measuring system, unit of contact temperature gauges, and device for bottom clamping connected with the end section of the blade. The device is provided with a means for axial loading, device for top clamping connected with the shelf of the end section of the blade, device for control of axial loading, first dynamometer, device for applying torque, which has the second dynamometer, device for information input, load-bearing frame, contactless temperature gauge, generator of nonstandard signals, oil pumping system, and device for internal cooling.

EFFECT: enhanced reliability of testing.

7 cl, 1 dwg

FIELD: measuring technique.

SUBSTANCE: method comprises heating the heat-shield structure from one side up to a high temperature, cooling the structure, applying marker dots on the section of the outer surface under study, cutting the axisymmetric specimens of the heat-shield structure, applying marker dots on the side of the specimen at a given distance from the inner surface, cutting the specimen over the planes perpendicular to its longitudinal axis and passing through the marker dots into pieces, subsequent heating of the pieces in the atmosphere of an inert gas, recording the change of weight of the pieces, recording the temperature of the beginning of the decrease of weight of each piece, and judging on the spatial temperature distribution from data obtained.

EFFECT: expanded functional capabilities.

5 dwg

FIELD: physics.

SUBSTANCE: stone sample saturated with water is frozen to a specified temperature. The sample is unfrozen and deformation is measured. Before freezing, the threshold load which accounts for long-term compression strength of the sample is measured using a nondestructive method. After several thermal cycles, residual deformation of the unfrozen sample is measured in the direction perpendicular the previous compression. A least residual deformation is achieved through periodical compression of the sample in the current direction from zero to a load which exceeds the threshold by not more than a third. The number of thermal cycles required for reducing long-term strength to the required value is determined by repeating these operations.

EFFECT: reduced labour input and increased efficiency.

1 tbl

FIELD: physics.

SUBSTANCE: method of determining heat resistance of bentonite clay is characterised by that, a nomograph which reflects dependency of temperature of the second endothermal effect and heat resistance of bentonite clay from contained structural iron is constructed first. For this purpose samples of bentonite clay from known deposits are analysed. The samples are tested in a derivatograph. Derivatograms with differential thermo-weighted (DTW) and differential thermal (DT) curves are obtained, from which temperature of the second endothermal effect is determined depending on structural iron contained in the samples. Heat resistance of the samples is determined depending on structural iron contained in the samples. From the said two curves, the said nomogram is constructed, which is then used for subsequent determination of heat resistance of the analysed bentonite clay; a wet ground up sample is tested in a derivatograph by heating followed by drying. Derivatograms with differential thermo-weighted and differential thermal curves are obtained, from which temperature of the second endothermal effect is determined and heat resistance of the analysed bentonite clay is determined from the said nomogram.

EFFECT: cutting on time and simplification of the process of determining heat resistance.

2 dwg

FIELD: physics.

SUBSTANCE: device has a cylindrical housing, a horizontal partition wall and sensors for monitoring and controlling tests. Inside the cylindrical housing, which has a flat bottom and an air-tight cover which is fixed by bolts and nuts in the top part, there is a drum which is mounted on the cover inside the housing. The horizontal partition wall is placed in the bottom part of the drum and is in form of a perforated disc whose perforations are in form of calibrated orifices lying on a circle, having along their edge calibrated channels for passage of heating medium. Inside the drum there is an additional horizontal partition wall with calibrated orifices which are exactly as those in the perforated disc. Sample pipes are fitted in the perforations of the disc and are fixed on the cover of the housing, and there are vertical partition walls between the pipes. Pipes with a smaller diameter are fitted inside each sample pipe and are fixed in a dispensing receiver and have in their top part connecting pipes for outlet of cooling medium and discharge pipes with calibrated devices on them. In the bottom part of the housing under the perforated disc there is a pipe with a diffusion nozzle connected to a cylindrical diffuser and a connecting pipe for inlet of heating medium and a system of chambers with a connecting pipe at the bottom for outlet of the heating medium.

EFFECT: high quality and accuracy of tests and efficiency thereof.

3 dwg

FIELD: transport.

SUBSTANCE: invention relates to space hardware testing, namely to installations for simulation of spacecraft components operation modes. Installation for vacuum thermocycling of photoconverter panels includes vacuum chamber consisting of two communicating compartments. In one compartment, two cryopanels are installed in parallel with possibility to place tested panel between them. In the second compartment there is thermal panel made as assembly of filament lamps. The cryopanels and thermal panel are positioned vertically, and thermal panel compartment is placed over cryopanel compartment. The cryopanels are installed with possibility of additional placement of thermal panel between them. The thermal panel is provided with reciprocating mechanism of vertical action and thermal insulation at the side facing cryopanel.

EFFECT: higher accuracy of thermal simulation of outer space conditions.

3 cl, 4 dwg

FIELD: testing equipment.

SUBSTANCE: device comprises a body with a flange joint and tested samples in the form of tubes. Tested samples in the amount of two arranged coaxially one inside the other to form a circular gap between them, are fixed inside separate parts of the body, placed on a header of hot water and a header of drainage of a mixture of hot and cold water. Headers by means of pipelines are connected to a heater and a refrigerator. The outer surface of the outer tube and the inner surface of the central tube are coated with a layer of insulation. In the upper part of the body there is a nozzle and a valve for supply and control of cooling water flow.

EFFECT: elimination of medium working pressure impact at process of crack formation, providing for pure crack formation only due to pulsation of medium temperature, which results in getting absolutely accurate testing results.

1 dwg

FIELD: test equipment.

SUBSTANCE: stand includes base, coaxial sample grips mounted on the base, sample loading device connected to the grips, mechanical sample processing device and platform for processing devise movement against grip axes. Additionally the stand features aggregate for grip turning around grip axis, consisting of drive with two gear wheels bearing the grips, on the drive shaft.

EFFECT: extended functionality of stand due to test performance at changing directions of mechanical processing against radial directions of sample.

1 dwg

FIELD: testing equipment.

SUBSTANCE: invention relates to testing equipment, to tests of mostly samples of rocks. The bench comprises a base, sample grips installed on it coaxially, a device to load a sample with an axial mechanical load, a mechanism for interaction with the sample, a platform for movement of the mechanism along the axis of the grips, a platform for movement of the mechanism in the vertical direction perpendicularly to the axis of the grips and a platform for movement of the mechanism in the horizontal direction perpendicularly to the axis of the grips. The mechanism for interaction with the sample is made as milling.

EFFECT: expansion of functional capabilities of a bench by provision of research with gradual removal of material sample without removal of mechanical load.

1 dwg

FIELD: test equipment.

SUBSTANCE: device includes gas generator and operation part with structural material sample, connected in series. Gas generator features removable mixing head. Cylindrical combustion chamber of the gas generator features ignition device and orifice plate. Operation part includes interconnected clamping flange with central hole and flange holding a sample. Central longitudinal axes of flange and sample are coincident. Internal cylindrical surface of clamping flange forms an annular slot with the sample surface, the slot joins a cavity ending with output nozzle through end outlet holes in the flange around sample.

EFFECT: possible maintenance of required pressure-heat loading modes for samples, modelling natural thermal stress state of structural materials of various aggregates operating in alternate heat modes.

1 dwg

Up!