Method for strengthening and toughening high-strength steel local region

A high-strength steel, strengthening and toughening technology, applied in the field of strengthening and toughening high-strength steel, can solve the problem of processing area limitations

Active Publication Date: 2021-09-14
JIMEI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the pulse sequence method is used, and the treatment area is limited to sub-centimeter width, and the strengthening and toughening mechanism is to form a phase transformation of a certain mass fraction of layered plastic phase (ie austenite) in addition to grain refinement. The toughness mechanism, there is no relevant literature disclosure

Method used

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  • Method for strengthening and toughening high-strength steel local region
  • Method for strengthening and toughening high-strength steel local region
  • Method for strengthening and toughening high-strength steel local region

Examples

Experimental program
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Effect test

Embodiment 1

[0050] Such as figure 1 As shown, the high-strength steel samples adjacent to Comparative Example 1 were intercepted, and processed into tensile test and impact test samples respectively as in Comparative Example 1. Install a tungsten alloy electrode with a diameter of 5mm on the moving electrode end of the working platform. Place the tensile specimen to be pulsed on the bench. On the control panel, set the current value of the crisping pulse to 17 A / mm 2 , the width is 30ms, and the distribution pulse current is 4 A / mm 2 , the width is 300ms, the pulse interval is 300ms, the sequence frequency is 1Hz, and the number of pulse sequences is 3. Start the pulse generator switch, the tungsten electrode is driven by the working platform to move down to the surface of the workpiece, and the pulse sequence is sent out. After the sequence number reaches the set number, the pulse switch is closed. The tungsten electrode was raised under the driving of the working platform, and the ...

Embodiment 2

[0055] The pulse sequence parameters of this embodiment 2 and embodiment 1 are the same, the difference is that the sample of embodiment 2 adopts the air cooling state after FH690 welding. Tensile test obtains the yield strength 692 N / mm of embodiment 2 2 , the tensile curve of embodiment 2 sees Figure 10 , the impact toughness value of Example 2 is 0.45 J / mm 2 , the impact toughness value of base metal is 0.46 J / mm 2 .

Embodiment 3

[0059] The implementation of the pulse sequence parameters in this embodiment 3 is the same as that of the embodiment 1, except that the sample material of the embodiment 3 is A36 steel. Tensile test obtains the yield strength 371 N / mm of embodiment 3 2 , the tensile curve of embodiment 3 sees Figure 11 . The impact toughness value of embodiment 3 is 0.19 J / mm 2 , the impact toughness value of the base material in Example 3 is 0.24 J / mm 2 . The current spot diameter is given by Figure 13 It can be seen that the horizontal leucorrhea in the figure is the spot of current action, and the width is less than 0.2mm.

[0060] Such as Figure 8 As shown, the present invention is a localized method for strengthening and toughening high-strength steel. After applying a pulse sequence to the welding heat-affected zone of high-strength steel, the grains of the microstructure become finer. Figure 7 In the scanning electron microscope image of the fracture, dimples appear on the ...

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Abstract

The invention discloses a method for strengthening and toughening a high-strength steel local region, which comprises the following steps of: installing a tungsten electrode on a moving end of a workbench, placing a sample on the workbench, and aligning a to-be-strengthened and toughened local region with the center of the tungsten electrode; starting a pulse power supply, and setting parameters of a pulse sequence control panel, which include sizes and widths of a brittleness elimination pulse current and a distribution pulse current, a frequency of a pulse sequence and a pulse interval width; turning on a pulse operation switch, and moving down the tungsten electrode to be in contact with the surface of a workpiece and acting on the high-strength steel local region; after the action time reaches the number set by the pulse sequence, turning off the pulse operation switch; and recovering the tungsten alloy electrode to a standby state. According to the method, cracks, impurities, coarse grains and the size of brittle components of the high-strength steel local region can be effectively eliminated and reduced, grain boundary film layered austenite is formed, the content of the grain boundary film austenite is increased, and the martensite grain size is refined, so that the strength and toughness of the local region are improved. The generated local region does not exceed 0.2 mm.

Description

technical field [0001] The invention relates to a method for strengthening and toughening steel, in particular to a method for locally strengthening and toughening high-strength steel. Background technique [0002] Cracks, brittle impurities (such as compounds of sulfur, phosphorus and other elements), brittle components (such as martensite in the outer layer of blocks and austenite in the inner layer) and stresses inevitably exist in the process of high-strength steel manufacturing and service. Soften and embrittle the steel locally. In particular, the width of the heat-affected zone of high-strength steel welding is on the order of sub-centimeters. The localized softening and embrittlement becomes the weak part of the structure, resulting in low stress failure of the structure and low service life. [0003] For the embrittlement and softening of steel, the currently widely used strengthening and toughening methods are heat treatment and current pulse treatment, which are...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D10/00
CPCC21D10/00C21D2211/001C21D2211/008
Inventor 陈章兰熊云峰李振宇李宗民李晓文
Owner JIMEI UNIV
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