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A kind of niti shape memory alloy and stainless steel electron beam welding method

A technology of electron beam welding and memory alloy, which is applied in the direction of electron beam welding equipment, welding equipment, metal processing equipment, etc., can solve problems such as weld cracking, achieve fast heating and cooling speed, improve mechanical properties, and form good effects

Active Publication Date: 2020-09-18
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

[0005] The object of the present invention is to provide a kind of NiTi shape memory alloy and stainless steel electron beam welding method, adopt FeNi alloy as intermediate transition layer, NiTi shape memory alloy and stainless steel are carried out electron beam welding, this method solves two kinds of materials when welding due to generation The problem of weld cracking caused by brittle phase can significantly improve the performance of welded joints between NiTi and 304 stainless steel dissimilar materials

Method used

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  • A kind of niti shape memory alloy and stainless steel electron beam welding method
  • A kind of niti shape memory alloy and stainless steel electron beam welding method
  • A kind of niti shape memory alloy and stainless steel electron beam welding method

Examples

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Embodiment 1

[0046] In this embodiment, the surfaces of the NiTi plate and the stainless steel plate with a thickness of 1.6 mm were firstly polished, and then ultrasonic cleaning was performed with acetone and alcohol solvents to remove oil stains, and then dried for later use. The thickness is 0.3mm, the FeNi alloy foil of equiatomic ratio is cut into 1.6mm wide, after pickling (by weight percentage, with the proportioning preparation pickling of 20% nitric acid+5% hydrofluoric acid+75% water solution), ultrasonically cleaned with acetone and alcohol for 20 minutes, and then dried for use. The treated FeNi alloy is placed between the NiTi plate and the stainless steel plate to be welded as an intermediate transition layer to form the welded piece and fixed to the fixture. A compressive stress of 0.2MPa is applied at both ends of the fixture to prevent the intermediate transition layer from falling off during welding. Put the parts to be welded together with the fixture into the vacuum c...

Embodiment 2

[0049] The difference from Example 1 is:

[0050] 1) The compressive stress applied at both ends of the fixture is 0.1MPa.

[0051] 2) The composition of the selected FeNi alloy intermediate transition layer is Fe: 45 at.% Ni: 55 at. %.

[0052] 3) Focus the electron beam on the side of the FeNi intermediate transition layer that is 0.2mm away from the stainless steel side (this is to make up for the difference caused by the difference in thermal physical properties when the two base materials are directly welded), and perform vacuum electron beam welding. The welding parameters are as follows: the welding speed is 800mm / min, the accelerating voltage is 40KV, the focusing current is 2325mA, the electron beam current is 15mA, and the working distance is 150mm. After the program is completed, cool in vacuum for 10 minutes, then remove the vacuum and take out the workpiece to complete the welding of NiTi shape memory alloy and stainless steel.

[0053] In this embodiment, the w...

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Abstract

The invention relates to the welding field of dissimilar materials of NiTi shape memory alloy and stainless steel, in particular to an electron beam welding method of NiTi shape memory alloy and stainless steel. By adding a FeNi alloy intermediate transition layer, vacuum electron beam welding is used to realize the welding of the two materials. The invention adopts the FeNi alloy as the intermediate transition layer material to form a certain amount of gamma (Fe, Ni) austenites in the weld zone, improves the toughness of a joint, reduces the brittle phase and remarkably improves the mechanical properties of the welded joint. Furthermore, the intermediate transition layer of FeNi can effectively restrain the segregation of chemical components in the fusion zone and ensure the mechanical properties of the welded joint to the maximum extent. The room temperature strength of the electron beam welded joint can reach 340 ~ 350 MPa after optimization of the parameters.

Description

technical field [0001] The invention relates to the field of welding dissimilar materials of NiTi shape memory alloy and stainless steel, in particular to an electron beam welding method of NiTi shape memory alloy and stainless steel. Background technique [0002] NiTi shape memory alloy (Shape Memory Alloy, referred to as SMA) as a special shape memory material, with its good shape memory effect (Shape Memory Effect, referred to as SME), superelasticity (Pseudoelasticity) and excellent biocompatibility and High damping, has become the most practical shape memory material. At present, it has broad application prospects in aerospace, atomic energy, mechanical electronics, marine development, instrumentation, and medical fields, and is called "the ideal material across the 21st century". After decades of development, the research work on the composition design and preparation process of NiTi alloy, the crystal structure of each phase, the thermoelastic martensitic transformat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K15/00
CPCB23K15/0006B23K15/0033B23K15/0046
Inventor 姜海昌牛浩赵明久潘雪新闫德胜戎利建
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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