CN102814580A

CN102814580A - Ultrasound arc welding method for ODS (Oxide Dispersion Strengthened) alloys

Info

Publication number: CN102814580A
Application number: CN2012102858107A
Authority: CN
Inventors: 雷玉成; 黄巍; 朱强; 承龙
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2012-08-13
Filing date: 2012-08-13
Publication date: 2012-12-12
Anticipated expiration: 2032-08-13
Also published as: CN102814580B

Abstract

The invention relates to arc welding of ODS (Oxide Dispersion Strengthened) alloys, in particular to an ultrasound arc welding method for the ODS alloys. The principle of the method is as follows: a method that the conventional arc welding power source is parallelly coupled to an ultrasonic excitation power source is adopted in the conventional ODS alloy arc welding process, ultrasonic alternating signals are coupled into a welding arc, then, ultrasonic waves are introduced into a fusion welding arc, the arc is enabled to serve as both a heat production mechanism and an ultrasonic emission mechanism, the emitted ultrasonic waves act on a welding pool of the ODS alloys and are used for removing gas in a weld seam and refining the structure of the weld seam, and thus, the mechanical property of weld seam joints of the ODS alloys is improved.

Description

A kind of ultrasonic arc-welding method that is used for the ODS alloy

Technical field

The present invention relates to the arc welding of ODS alloy, refer in particular to a kind of ultrasonic arc-welding method of the ODS of being used for alloy.

Background technology

The ODS alloy is oxide dispersion intensifying (the Oxide dispersion strengthened that adopts the mechanical alloying method to make; ODS) high temperature alloy; Has the good comprehensive advantage of mechanical behavior under high temperature, high-temperature oxidation resistant and corrosion resistance; In Aeronautics and Astronautics and nuclear energy field etc. has the parts of high temperature resistant requirement, be widely used at present, make powder stand repeatedly distortion, cold welding, fragmentation owing to mechanical alloying is one through high-energy ball milling, thereby reach the complicated physical and chemical process of atomic level alloying between element; Therefore the ODS alloy prepares the refinement that particle often takes place in the process; And the introducing defective, make isolation fine pore residual in the material be difficult to eliminate, become residual hole.In the melting process, these holes can cause in the molten bath metal flow irregular, form pore fast in the cooled and solidified process easily; Simultaneously, the ODS alloy is in metallurgical non-equilibrium state, welds relatively difficulty with conventional melting method; Be easy to generate the thick problem of weld grain etc.; Heavy damage original tissue and the performance of material, therefore fundamentally improve the performance of weld metal, just must crystal grain thinning, reduce pore.

In prior art; Application number is that " based on the aluminium alloy of alternating current arc excitation ultrasound and the aluminum matrix composite welding " of CN101797659A is primarily aimed at aluminium alloy and aluminum matrix composite for the 201010123736.X publication number; Adopt alternating current arc to weld; Utilize the RC high-pass filter to realize the coupling of ultrasonic action electric current and welding current; But because the ODS alloy is to adopt direct-current arc to weld, therefore in the ultrasonic action loop, needs to add capacitance and carry out electricity isolation, prevent the direct current ultrasonic action source of breaking; Preparation method owing to the ODS alloy has determined need can control in real time the ultrasonic action electric current that gets into welding current in the welding process simultaneously; Therefore in the ultrasonic action loop, also need add rheostat, to be used for the size that real-time regulated is loaded into the ultrasonic action voltage and current of electric arc.

Summary of the invention

The objective of the invention is to propose a kind of ultrasonic arc-welding method of new method-ODS alloy of the ODS of being used for alloy melting weldering; Its principle is in conventional ODS alloy Arc Welding Process, through with the method for the Arc Welding Power parallel coupled ultrasonic action power supply of routine, make the ultrasonic wave alternating signal be coupled into welding arc; Thereby ultrasonic wave is incorporated in the melting electric arc; Make electric arc promptly as heat production mechanism, simultaneously again as ultrasound emission mechanism, the ultrasonic wave of launching acts on the welding pool of ODS alloy; Utilize ultrasonic wave to remove gas and refinement seam organization in the weld seam, thereby improve the mechanical property of ODS alloy welding line joint.

The arc-ultrasonic welding method of the ODS alloy that the present invention proposes may further comprise the steps:

(1) encourages the generation source to be connected with Arc Welding Power in parallel arc-ultrasonic, make the supersonic frequency alternate electrical signal be coupled into welding arc; The capacitance that utilizes series connection to enter the ultrasonic action loop carries out electricity isolates, with protection ultrasonic action source; The size of the ultrasonic action voltage and current that rheostat of series connection is used for regulating being loaded into electric arc in the ultrasonic action loop simultaneously;

The selection of capacitance capacitance: because the ODS alloy adopts direct current to weld, and welding current is big, and (be generally 60 ~ 150A), for effectively protecting the ultrasonic action source, prevent that it is soldered electric current and breaks, the capacitance capacitance should suitably select more greatly; But because ultrasonic action electric current less (being 30A to the maximum) can effectively be coupled with welding current for guaranteeing the ultrasonic action electric current, and capacitance again can not be too big, therefore, selecting the capacitance capacitance in the present invention for use is 40 ~ 100PF.

The selection of rheostat Standard resistance range: because the ultrasonic action electric current is less, therefore only need select for use the rheostat of little resistance to get final product, selecting rheostatic Standard resistance range in the present invention for use is 0 ~ 200 Ω.

(2) connect the ultrasonic action power supply again after the welding starting the arc; The selection dutycycle is 50% square wave excitation source, and driving frequency is 28 ~ 80KHz, and it is preferably 30KHz; Exciting current is 0 ~ 30A, realizes that through the high frequency modulated to welding arc alternate electrical signal is to hyperacoustic power conversion;

(3) after realizing the coupling of ultrasonic wave and welding arc, select for use conventional TIG welding method that the ODS alloy is welded.

Description of drawings

Fig. 1 is the section of weld joint figure and the micro-organization chart of the conventional TIG weldering of MGH956 alloy;

(a) section of weld joint; (b) weld seam microscopic structure;

Fig. 2 is the principle schematic of the inventive method;

Among the figure: 1-source of welding current; 2-ultrasonic action power supply; 3-electric arc; 4-workpiece; 5-rheostat; 6-partiting dc capacitor; 7-ammeter; 8-voltmeter;

Fig. 3 is a MGH956 alloy arc-ultrasonic TIG welding line sectional view, and a, b, c, d figure apply 5A, 10A, 20A and 30A ultrasonic action electric current respectively among the figure;

Fig. 4 is a MGH956 alloy arc-ultrasonic TIG welding line micro-organization chart, and a, b, c figure apply 10A, 20A and 30A ultrasonic action electric current respectively among the figure.

The specific embodiment

Materials to be welded is selected the MGH956 alloy for use, and the MGH956 alloy is a kind of typical material in numerous ODS high temperature alloys, and this alloy adopts ultra-fine overstable oxide particle (Y ₂O ₃) matrix is strengthened, have that mechanical behavior under high temperature is good, high-temperature oxidation resistant and a good comprehensive advantage of high-temperature corrosion-resistance performance, have wide practical use at aspects such as Aeronautics and Astronautics, nuclear energy.

Its chemical composition is as shown in table 1.

The chemical composition of table 1 MGH956 alloy (mass fraction, %)

Comparative Examples:

Before the welding, (surface of 70mm * 35mm * 1.5mm) and groove place clean out, and using model is MW3000 inversion total digitalization tungsten argon arc welding machine with the mother metal test plate (panel); The tungsten electrode diameter is 2.4mm, straight polarity direct current, and adopting purity is that 99.9% argon gas is as protection gas; Gas flow is 7.5L/min; Welding current 70A, weldingvoltage 12V, speed of welding 1.8mm/s.

More than be the conventional TIG welding method welding parameter of (not adding the excitation ultrasonic wave), the postwelding section of weld joint is shown in Fig. 1 a.It is thus clear that have a large amount of pores in the weld seam, and weld grain is thicker, be mostly dendroid crystal grain, shown in Fig. 1 b.

Embodiment:

Arc-ultrasonic ODS gold alloy solder connection technology through with the method for the Arc Welding Power parallel coupled ultrasonic action power supply of routine; Realize encouraging coupling ultrasonic and welding arc; Make welding arc promptly as thermal source; As ultrasound emission mechanism, in welding, utilize ultrasonic wave to remove gas and refinement seam organization in the weld seam again.

The schematic diagram of the inventive method is as shown in Figure 2.

It is 80KHz that arc-ultrasonic driving source 2 can produce the maximum excitation frequency; The maximum excitation electric current is the overclocking alternation square-wave signal of 30A; Peak power can reach 1500W, and the method through resistance-capacitance coupling is together in parallel itself and melting Arc Welding Power, thereby realizes the coupling of ultrasonic wave and welding arc; Because the method for straight polarity direct current is adopted in the welding of ODS alloy; Therefore in the ultrasonic action loop, add partiting dc capacitor (40 ~ 100PF) 6; Reach the purpose that protection ultrasonic action power supply is not influenced by the source of welding current, and the size of the ultrasonic action voltage and current of regulating to be loaded in the electric arc through a rheostat of access (0 ~ 200 Ω).

After realizing the coupling of ultrasonic wave and welding arc, still select for use conventional TIG welding parameter that the ODS alloy is welded, use model to be MW3000 inversion total digitalization tungsten argon arc welding machine; The tungsten electrode diameter is 2.4mm, straight polarity direct current, and adopting purity is that 99.9% argon gas is as protection gas; Gas flow is 7.5L/min, welding current 70A, weldingvoltage 12V; Speed of welding 1.8mm/s produces ultrasonic wave because arc-plasma receives the excitation of the supersonic frequency signal of telecommunication, acts on the weld seam molten bath; Therefore reduce air vent content, refinement weld grain in the weld seam and improved mechanical property, the especially tensile strength of weld seam to a certain extent.

Fig. 3 is the ODS alloy weld seam sectional view when applying different exciting current, compares with conventional TIG weldering, along with the increase of exciting current; Pore quantity in the weld seam obviously reduces, and size also obviously reduces, and brings up to 20A when exciting current; The pore minimum number; This shows, in welding arc, introduce the quantity that ultrasonic wave can reduce pore in the weld seam effectively, reach the purpose of degasification.

Fig. 4 is the ODS alloy weld seam micro-organization chart when applying different exciting current, and when the ultrasonic action electric current was brought up to 20A, the weld grain size was minimum, and therefore, ultrasonic arc welding technology has positive effect for the refinement weld grain.

MGH956 alloy arc-ultrasonic TIG weldering is compared with conventional TIG weldering, and its welding line joint tensile strength is improved significantly, and table 2 is comparisons of MGH956 joint tensile property.

Table 2 MGH956 alloy weld seam tensile property

When in production practices, using this solder technology; Need not original welding equipment is transformed; Can directly Arc Welding Power be connected through this isolation coupling device with the high frequency ultrasound excitation power supply; Realization improves ODS alloy quality of weld joint to the technology upgrading of legacy equipment, is with a wide range of applications.

Claims

1. ultrasonic arc-welding method that is used for the ODS alloy is characterized in that may further comprise the steps:

2. a kind of ultrasonic arc-welding method that is used for the ODS alloy as claimed in claim 1, it is characterized in that: said capacitance capacitance is 40 ~ 100PF.

3. a kind of ultrasonic arc-welding method that is used for the ODS alloy as claimed in claim 1, it is characterized in that: said rheostatic Standard resistance range is 0 ~ 200 Ω.