SU1308873A1 - Method of studying material yield under hightemperature - Google Patents

Abstract

The invention relates to the improvement of mechanical testing methods and can be used to study the laws of flow, determining the yield strength of a metal in technological processes. The purpose of the invention is to improve the accuracy of use due to torsional loading. The method consists in loading the sample of the material in torsion at the temperature of the beginning of recrystallization and stepwise unloading it by heating, starting from the lower limit of the temperature of recrystallization. At each stage of unloading, the magnitude of the torque is measured and, according to its variation, the yield strength of the sample material is judged. from 00 sh with

Description

eleven

The invention relates to the improvement of mechanical testing methods and can be used to study the laws governing the determination of the fluidity of a metal in hot metal forming processes.

The purpose of the invention is to increase the accuracy of the study by obtaining a uniaxial stress state of the test material, torsion,

The method consists in heating a sample of the material to a temperature above the temperature of the onset of recrystallization, then loading it with torsion to a value of shear deformation corresponding to the technological processes of hot working with pressure of this metal and holding it at that temperature under load until the torque stabilizes. At this time, the torque value corresponds to the yield point at shear of the material under study at a given fixed temperature. Then the sample is stepwise unloaded in proportion to the change in its yield strength during shear due to its heating in the furnace, starting from the lower limit of the sample heating temperatures. At each temperature stage, the sample is held inside the furnace under isothermal conditions to

one

the invention of the end of softening (torque stabilization), according to the change in the rotational momentum formula, is determined by the fluidity of the material. Thermal expansion of the grippers of the testing machine and the sample is compensated for by removing the axial connection during its deformation. The sample unloading at each temperature level occurs due to its short-term creep under step heating under load, in a rigid elastic system.45 starting from the recrystallization temperature- The aluminum alloy of AKChtion was investigated,

350 - that, in order to improve the accuracy of the study, loading is carried out by torsion to a deformation value of 0.55, which corresponds to the forging of large shear, unloading in each step ingots of this alloy on hydraulic - - until the hydraulic presses are stabilized . Investigation of the moment and change in the twist was carried out on the upgraded test moment in the stages, judging the KM-50-1 flow machine. To investigate the material.

The method of studying the fluidity of the material at high temperatures, namely, that the sample of the material is loaded at a temperature above the recrystallization temperature, is scaled at this temperature under load until the end of softening, and is stepwise unloaded by heating.

1 h in the temperature range

 at warp speed

 .0,002 s and the degree of deformation 6

VNIIPI Order 1790/34 Circulation 777 Subscription Proizv.-poly. pr-tie, Uzhgorod, st. Project, 4

Torsion samples with a diameter of 4 and 3.5 mm and a working section length of 40 mm were used for the additions. A sample with a diameter of 4 mm, mounted in the working grippers, was placed inside the furnace. A chromel-aluminum thermocouple was pressed to the sample, the signal from which was fed to the calibration instrument. The sample was heated to the minimum temperature (350 ° C). After heating the sample at

five

0

five

0

At a given temperature, it was twisted in a rigid elastic system and, when it reached a given degree of deformation, the machine stopped without removing the torque on the specimen. After stopping the machine, the metal of the sample was softened. The termination of the softening was judged by the stabilization of torque. After that, the loaded sample was heated to the next temperature (400 ° C) and the change in the twist angle and torque on the sample, etc. was measured at this temperature. to the upper limit of the temperature range of testing. The current twist angle of the sample during the experiment was measured and recorded on the tape of the chart device. At the same time, the current torque and process time were recorded on the tape. Whether the difference between the torques and by it was determined was the material's fluidity.

one

isobormula starting from temperature

35 Formula 45 starting from recrystallization temperature, characterized in

The method of studying the fluidity of the material at high temperatures, namely, that the sample of the material is loaded at a temperature above the recrystallization temperature, is scaled at this temperature under load until the end of softening, and is stepwise unloaded by heating.

Claims (1)

Claim· 1 ' , A method for studying the fluidity of a material at high temperatures, namely, that a sample of the material is loaded at a temperature above the recrystallization temperature, it is held at this temperature under load until the softening is completed, and it is gradually unloaded by heating, starting from the recrystallization temperature, characterized in that, with In order to improve the accuracy of the study, loading is carried out by torsion to the value of shear strain, unloading in each stage is carried out until the torque is stabilized and torque in NIJ levels are judged on the strength of the material. ВНИИПИ Order 1790/34 Circulation 777 Subscription Custom polygr. ave, city of Uzhhorod, st. Project, 4