CN103042306A - Method for measuring effects of gravity on laser welded joint welded seam shapes - Google Patents

Abstract

The invention discloses a method for measuring effects of gravity on laser welded joint welded seam shapes. The method comprises that a metal plate is installed on an adjustable press device which is provided with press arrangements in horizontal and vertical directions; laser serves as a heat source, welding with the laser welding direction vertical to or parallel with the gravity direction is performed, and preset technological parameters are selected to enable metal to produce conduction welding or deep penetration welding type welded seam characteristics; a wire cut electric discharge machine is used for performing linear cutting on the plate along the direction perpendicular to the welding direction after welding; a scanning electron microscope is used for observation to obtain welded seam cross section shapes, and effects of gravity on welded seam shapes are studied qualitatively by observation of welded seam cross section shape images tested in different welding directions; and image analysis software measures welded seam cross section shape images, and effects of gravity on welded seam shapes are analyzed qualitatively by comparing different welding directions to obtain weld widths and weld depths.

Description

A kind of gravity is on the measuring method of laser weld joint weld seam form impact

Technical field

The invention belongs to welding technology field, relate to a kind of metal laser welding measuring method, relate in particular to a kind of measuring method of gravity butt joint weld seam form impact.

Background technology

Along with developing rapidly of laser welding technology, laser weld has become a key technology in the modern manufacturing fields such as automobile making, large-sized structural parts, space structure manufacturing gradually.Because the welding condition of laser often is in welding direction and is different from gravity direction, even under microgravity or the genvironments, thereby gravity receives much concern on the impact of laser welding structure spare weld seam form.

The molten bath is to form under the buoyancy-driven that kickback pressure, surface tension and gravity cause and (the Semak that develops in the laser weld, V.V., et al.ACONCEPTFOR A HYDRODYNAMIC MODEL OF KEYHOLE FORMATION AND SUPPORT DURING LASER WELDING.1994.Orlando, Fl:Spie-Int Soc Optical Engineering), gravity effect the formation of form and the micro-structural in molten bath.In existing research, have under the research genvironments, such as document 1, AIDUN, D., J.DOMEY, and G.AHMADI, Effect of High Gravity on Weld Fusion Zone Shape.2000 discloses a kind of experimental rig of simulating under the genvironments in the document, checking gravity is on the weld seam form of GTA welding and the impact of tissue.Document 2, Kang, N.Y., J.Singh, and A.K.Kulkarni.Gravitational effects on the weld pool shape and microstructural evolution during gas tungsten arc and laser beam welding of 304 stainless steel and Al-4wt% Cu alloy.2003.Davos, SWITZERLAND:New York Acad Sciences, the document discloses joint surface pattern and the weld seam form of simulating GTAM welding under 1.2g and the 1.8g gravity environment in the KC-135 aircraft.Research is arranged against gravity direction welding, such as patent 1, Manabe, a kind of method that welding direction makes progress under the ground gravity environment of Yukio.et al.Welding method in the overhead and vertical this patent disclosure of positions.EP0832710-B1. can solve the Gravity Problem that needs upwards welding to face in large space structure.

Because the cost of testing under microgravity or genvironments is huge, the requirement of experimental technique is high.Impact for research gravity butt welded seam form is necessary to explore the method for carrying out simulated test under ground environment.

Summary of the invention

The object of the present invention is to provide a kind of gravity on the measuring method of laser weld joint weld seam form impact, can under the ground gravity environment, inquire into the impact of gravity butt welded seam form, also can with overweight or microgravity environment under experimental result compare.

A kind of gravity provided by the invention on the measuring method of laser weld joint weld seam form impact is:

1) sheet metal is installed on the adjustable hold down gag, this device has the compression setting of horizontal direction and vertical direction;

2) take laser as thermal source, carry out the laser weld perpendicular direction or be parallel to the welding of gravity direction, by the technological parameter of selecting to be scheduled to, make metal produce the characteristics of weld seam of conduction weldering or deep penetration welding formula;

3) postwelding utilizes WEDM that sheet material is carried out the line cutting along the vertical weld direction;

4) utilize scanning electronic microscope observation to obtain the seam cross-section pattern, the observation by to the weld seam pattern of different welding directions test comes the impact of qualitative research gravity butt welded seam form;

5) utilize image analysis software butt welded seam cross-sectional morphology figure to measure, obtain molten wide, the fusion penetration value of weld seam by contrasting different welding directions, come the impact size of quantitative analysis gravity butt welded seam form.

The present invention can inquire into the impact of gravity factor butt welded seam form in the gravity field on earth's surface environment, also can with overweight or microgravity environment in result of the test compare.The method can provide reference to utilizing laser to carry out large-sized structural parts welding effect under different directions, is beneficial to the optimization of technological parameter.

Description of drawings

Fig. 1 is weight-driven molten bath flow schematic diagram (molten bath cross section) in the laser weld;

Fig. 2 is different laser weld direction lower device schematic diagrames;

1---adjustable hold-down bolt;

2---test button;

3---pressing plate;

4---the matrix fixing hole;

5---adjustable hold down gag matrix.

Fig. 2 a---weld downward or upward perpendicular to gravity direction

Fig. 2 b---perpendicular to the gravity direction transverse weld

Fig. 2 c---be parallel to the welding of gravity direction level

Fig. 3 is four welding direction schematic diagrames;

1.---be parallel to the welding of gravity direction level, corresponding intrument (Fig. 2 c)

2.---perpendicular to upwards welding of gravity direction, (Fig. 2 is a) for corresponding intrument

3.---weld downwards perpendicular to gravity direction, (Fig. 2 is a) for corresponding intrument

4.---perpendicular to the gravity direction transverse weld, corresponding intrument (Fig. 2 b)

Fig. 4 sheet material line cutting schematic diagram;

1 '---weld seam;

2 '---the line cutting position;

3 '---sheet material;

The fusion penetration of Fig. 5 weld seam melts wide schematic diagram;

Fig. 6 is 4 kinds of weld seam patterns that welding manner is corresponding in the example 1;

Fig. 7 is 4 kinds of weld seam patterns that welding manner is corresponding in the example 2.

The specific embodiment

As can be known, having under the action of gravitation in existing research, when being parallel to the welding of gravity direction level, the molten bath has the characteristics that fusion penetration reduces molten wide increase, as shown in Figure 1.Therefore, if change the direction of gravity and laser weld, the form in molten bath can change to some extent.For this reason, the present invention has designed the experimental provision that can carry out different welding directions, shown in Fig. 2 a～c.Because the welding direction of Fig. 2 a, 2b is perpendicular to gravity direction, from the cross section of molten bath, Fig. 2 a and Fig. 2 b can not be subject to the impact of gravity among Fig. 2 c.

Measuring method of the present invention is specific as follows:

Shown in Fig. 2 a～c, test button 2 is installed on the matrix 5 of adjustable hold down gag by pressing plate 3, offer matrix fixing hole 4 on the matrix 5, pressing plate 3 is fixed on the matrix 5 by bolt 1.Shown in Fig. 2 a～c; this device has the compression setting of horizontal direction and vertical direction; take laser as thermal source; carry out the laser weld perpendicular direction or be parallel to the soldering test of gravity direction; by selecting rational technological parameter; make metal produce the characteristics of weld seam of conduction weldering or deep penetration welding formula, do not use protection gas for the impact that reduces the destabilizing factors such as environment in the test, the experimental condition of metal sheet and all directions is the same.

Postwelding utilizes WEDM that sheet material is carried out the line cutting along the vertical weld direction, and as shown in Figure 4,1 ' is weld seam among the figure, and 2 ' is the line cutting position, and 3 ' for forming the test button of weld seam.Utilize scanning electronic microscope observation to obtain the seam cross-section pattern, the observation by to the weld seam pattern of different welding directions test comes the impact of qualitative research gravity butt welded seam form; In addition, utilize Potoshop butt welded seam cross-sectional morphology figure to measure, obtain molten wide, the fusion penetration value of weld seam by contrasting different welding directions, as shown in Figure 5, come the impact size of quantitative analysis gravity butt welded seam form.

Below by concrete example explanation.

Concrete example: for convenience of explanation, the rough schematic view of Fig. 2 is seen Fig. 3.

Example 1: at laser power 200W, speed of welding 25m/s, during defocusing amount 0, the laser weld Pool is the molten pool character of conduction weldering.The weld seam form of all directions is seen Fig. 6.Since Fig. 3 2. 3. 4. cross-sectional direction be not affected by gravity, 1. its molten wide ratio little, fusion penetration is large than 1., conforms to existing research.

Example 2: at laser power 400W, speed of welding 10m/s, during defocusing amount 0, the laser weld Pool is the molten pool character of deep penetration welding weldering.The weld seam form of all directions is seen Fig. 7.1. molten wide all larger than other as seen from the figure, fusion penetration is less.

This shows the impact of gravity butt welded seam form, in the conduction weldering of laser weld and deep penetration welding, identical action effect is arranged.This measuring method test is simple, it is convenient to measure, avoided device design and the harsh environmental requirement of document 1,2 complexity, can in the gravity field on earth's surface environment, inquire into the impact of gravity factor butt welded seam form, also can with overweight or microgravity environment in result of the test compare.The method can provide reference to utilizing laser to carry out large-sized structural parts welding effect under different directions, is beneficial to the optimization of technological parameter.

Claims (1)

1. a gravity on the measuring method that laser weld joint weld seam form affects is:

1) sheet metal is installed on the adjustable hold down gag, this device has the compression setting of horizontal direction and vertical direction;

2) take laser as thermal source, carry out the laser weld perpendicular direction or be parallel to the welding of gravity direction, by the technological parameter of selecting to be scheduled to, make metal produce the characteristics of weld seam of conduction weldering or deep penetration welding formula;

3) postwelding utilizes WEDM that sheet material is carried out the line cutting along the vertical weld direction;

4) utilize scanning electronic microscope observation to obtain the seam cross-section pattern, the observation by to the weld seam pattern of different welding directions test comes the impact of qualitative research gravity butt welded seam form;

5) utilize image analysis software butt welded seam cross-sectional morphology figure to measure, obtain molten wide, the fusion penetration value of weld seam by contrasting different welding directions, come the impact size of quantitative analysis gravity butt welded seam form.

Images