CN103042306B - 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 measuring method of gravity butt joint weld seam form impact

Technical field

The invention belongs to welding technology field, relate to a kind of metal laser welding measuring method, particularly relate to the measuring method of a kind 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 manufacture gradually.Welding condition due to laser is often in welding direction and is different from gravity direction, and even under microgravity or genvironments, thus the impact of gravity on laser welding structure part weld seam form receives much concern.

In laser weld, molten bath is the (Semak of early Pleistocene under the buoyancy-driven caused at kickback pressure, surface tension and gravity, V.V., et al.A CONCEPT FOR A HYDRODYNAMIC MODEL OF KEYHOLE FORMATION AND SUPPORT DURING LASER WELDING.1994.Orlando, Fl:Spie-Int Soc Optical Engineering), gravity effect the form in molten bath and the formation of micro-structural.In existing research, have research genvironments under, 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 genvironments in the document, the impact of the weld seam form that checking gravity welds GTA and 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 304stainless steel and Al-4wt%Cu alloy.2003.Davos, SWITZERLAND:New York Acad Sciences, the document discloses the joint surface pattern and weld seam form of in KC-135 aircraft, to simulate GTAM welding under 1.2g and 1.8g gravity environment.Research is had to weld against gravity direction, as patent 1, Manabe, this patent of Yukio.et al.Welding method in the overhead and vertical positions.EP0832710-B1. disclose a kind of under ground gravity environment welding direction method upwards, can solve and need upwards to weld the Gravity Problem faced in large space structure.

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

Summary of the invention

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

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

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

2) taking laser as thermal source, carry out the welding that laser weld direction is perpendicular or parallel with gravity direction, by selecting predetermined technological parameter, making metal produce the characteristics of weld seam of conduction weldering or deep penetration welding formula;

3) postwelding utilizes WEDM to carry out Linear cut to sheet material along vertical weld direction;

4) utilize scanning electronic microscope observation to obtain seam cross-section pattern, by the observation of seam center tested different welding direction, carry out the impact of qualitative research gravity butt welded seam form;

5) utilizing image analysis software butt welded seam cross-sectional morphology figure to measure, obtaining molten wide, the fusion penetration value of weld seam by contrasting different welding direction, that carrys out quantitative analysis gravity butt welded seam form affects size.

The present invention can inquire into the impact of gravity factor butt welded seam form in gravity field on earth's surface environment, also can contrast with the result of the test in overweight or microgravity environment.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.

Accompanying drawing explanation

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

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

1---adjustable hold-down bolt;

2---test button;

3---pressing plate;

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

Fig. 4 sheet material Linear cut schematic diagram;

1 '---weld seam;

2 '---Linear cut position;

3 '---sheet material;

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

Fig. 6 is the seam center that in example 1,4 kinds of welding manners are corresponding;

Fig. 7 is the seam center that in example 2,4 kinds of welding manners are corresponding.

Detailed description of the invention

Known in existing research, under the effect having gravity, when being parallel to the welding of gravity direction level, molten bath has the feature 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 devises the experimental provision that can carry out different welding direction, as shown in Fig. 2 a ~ c.Because the welding direction of Fig. 2 a, 2b is perpendicular to gravity direction, from molten bath cross section, Fig. 2 a and Fig. 2 b can not be subject to the impact of gravity in Fig. 2 c.

Measuring method of the present invention is specific as follows:

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

Postwelding utilizes WEDM to carry out Linear cut to sheet material along vertical weld direction, and as shown in Figure 4, in figure, 1 ' is weld seam, and 2 ' is Linear cut position, and 3 ' is the test button forming weld seam.Utilize scanning electronic microscope observation to obtain seam cross-section pattern, by the observation of seam center tested different welding direction, carry out the impact of qualitative research gravity butt welded seam form; In addition, utilizing Potoshop butt welded seam cross-sectional morphology figure to measure, obtaining molten wide, the fusion penetration value of weld seam by contrasting different welding direction, as shown in Figure 5, that carrys out quantitative analysis gravity butt welded seam form affects size.

Illustrate below by way of concrete example.

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

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

Example 2: at laser power 400W, speed of welding 10m/s, during defocusing amount 0, laser weld pools pattern is the molten pool character of deep penetration welding weldering.The weld seam form of all directions is shown in 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 and deep penetration welding of laser weld, have identical action effect.The test of this measuring method is simple, it is convenient to measure, avoid the apparatus design of document 1,2 complexity and the environmental requirement of harshness, the impact of gravity factor butt welded seam form can be inquired in gravity field on earth's surface environment, also can contrast with the result of the test in overweight or microgravity environment.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 adjustable hold down gag, the compression that this device has horizontal direction and vertical direction is arranged;

2) taking laser as thermal source, carry out the welding that laser weld direction is perpendicular or parallel with gravity direction, by selecting predetermined technological parameter, making metal produce the characteristics of weld seam of conduction weldering or deep penetration welding formula;

3) postwelding utilizes WEDM to carry out Linear cut to sheet material along vertical weld direction;

4) utilize scanning electronic microscope observation to obtain seam cross-section pattern, by the observation of seam center tested different welding direction, carry out the impact of qualitative research gravity butt welded seam form;

5) utilizing image analysis software butt welded seam cross-sectional morphology figure to measure, obtaining molten wide, the fusion penetration value of weld seam by contrasting different welding direction, that carrys out quantitative analysis gravity butt welded seam form affects size.