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Cyclic torsion machining process for improving mechanical property of metal material

A technology of metal materials and processing technology, applied in the field of cyclic torsion processing technology, can solve the problems of limited strength, mechanical instability, complex equipment, etc., and achieve high yield strength and tensile strength, uniform plasticity and elongation at break, good Effect of Strength and Plasticity Matching

Active Publication Date: 2020-03-27
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the limited thickness of the surface nanocrystalline layer in the gradient nanocrystalline structure obtained by the prior art and its intrinsic mechanical instability, the further improvement of its strength is limited.
More importantly, the equipment used in several surface deformation processes currently developed, such as surface mechanical grinding and surface rolling treatment technology, is relatively complicated, and it is necessary to use cemented carbide cutter heads with special geometric dimensions to grind or grind the metal surface. Rolling treatment, the process technology is harsh, and the treatment efficiency is low, which seriously limits its wide application in industry

Method used

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  • Cyclic torsion machining process for improving mechanical property of metal material
  • Cyclic torsion machining process for improving mechanical property of metal material
  • Cyclic torsion machining process for improving mechanical property of metal material

Examples

Experimental program
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Effect test

Embodiment 1

[0034] In this embodiment, 304 austenitic stainless steel rods are subjected to small-angle cyclic reciprocating torsional deformation treatment.

[0035] Fix one end of the coarse-grained 304 austenitic stainless steel sample, and apply cyclic torsional deformation to the other end (such as figure 1 Shown), the gradient structure 304#1 sample was obtained.

[0036] The process parameters of the gradient structure 304#1 sample are selected as follows: the diameter of 304 austenitic stainless steel is 6 mm, the torsion angle amplitude is 5 degrees, the torsion speed is 5000° / min, the torsion cycle is 200 cycles, and the torsion time is about 14 seconds. The temperature is room temperature 25 degrees.

[0037] As the depth from the surface increases, the degree of deformation in the material presents a monotonically decreasing trend, forming a gradient distribution of deformation microstructure ( figure 2 ). However, the microstructure is still austenite and no martensite ph...

Embodiment 2

[0040] In this embodiment, a cyclic torsional deformation treatment is applied to the coarse-grained 304 austenitic stainless steel #2 sample to obtain a 304 #2 sample with a gradient structure.

[0041] The difference from Example 1 is that the process parameters of the gradient structure 304#2 sample are selected as follows: the diameter of 304 austenitic stainless steel is 6 mm, the torsion angle amplitude is 15 degrees, the torsion speed is 5000 ° / min, and the torsion cycle is 200 cycles , the torsion time is about 6 minutes, and the torsion temperature is 25 degrees at room temperature.

[0042] As the depth from the surface increases, the degree of deformation in the material presents a monotonically decreasing trend, forming a gradient distribution of deformation microstructure ( figure 2 ). The outermost surface is still coarse-grained ( Figure 4 ), there are high-density dislocations distributed inside the coarse grain, a large number of dislocation cells and disl...

Embodiment 3

[0050] This example is for coarse-grained Al 0.1 CoCrFeNi high-entropy alloy samples subjected to cyclic torsional deformation treatment.

[0051] The process parameters of gradient structure high-entropy alloy #2 samples are selected as follows: Al 0.1 The CoCrFeNi high-entropy alloy sample diameter is 4.5mm, the torsion angle amplitude is 15 degrees, the torsion speed is 1800° / min, the torsion cycle is 200 cycles, the torsion time is about 3 minutes, and the torsion temperature is 25 degrees at room temperature.

[0052] As the depth from the surface of the material increases, the microhardness of the gradient structure high-entropy alloy #2 sample gradually decreases from 4.0GPa to 2.4GPa, which has the characteristics of a gradient change, which is significantly higher than that of the coarse-grained high-entropy alloy sample (1.7GPa), such as Figure 9 shown.

[0053] In this embodiment, the gradient structure high-entropy alloy #2 sample is subjected to uniaxial tensil...

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Abstract

The invention discloses a cyclic torsion machining process for improving the mechanical property of a metal material, and belongs to the technical field of metal material strengthening. Specifically,the process comprises the steps: applying small-angle circulating torsional deformation to a metal bar, a pipe or a plate sample, and generating shear shaping strain in gradient distribution from thesurface to the interior of a metal material, so deformation microstructures such as dislocation in gradient distribution and nano twin crystals are introduced, and an original coarse grain structure is reserved, wherein the torsion angle amplitude is between 2 degrees and 30 degrees, and the number of torsion cycles is between 2 and 200. Compared with a uniform coarse grain structure with the samecomponents, the metal material treated by the circulating torsion process is improved by more than 1.5 times in yield strength, and the metal material has uniform plasticity equivalent to that of coarse grains. By utilizing the method, the microstructure with gradient distribution is obtained in the original coarse grain and has high strength and good plasticity matching.

Description

technical field [0001] The invention relates to the technical field of metal material strengthening, in particular to a cycle torsion process for improving the mechanical properties of metal materials. Background technique [0002] Metal materials are widely used in almost all industrial fields such as aerospace, petrochemical, and transportation due to their comprehensive mechanical and physical and chemical properties such as strength, plasticity, and toughness. They are an important class of indispensable materials for human society. In recent years, with the development of society, resources are increasingly scarce, energy consumption and environmental pollution are intensifying, which forces metal components and equipment to continue to develop in the direction of high performance, light weight, energy saving and environmental protection, and the service environment is becoming more and more complex. Microstrength Traditional structural metal materials with low hardness...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D10/00C22F3/00
CPCC21D10/00C22F3/00
Inventor 卢磊潘庆松崔方
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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