CN1748927A - Method for preventing aluminum alloy stirring friction welding seam crystal particle from abnormal growth in heat process - Google Patents
Method for preventing aluminum alloy stirring friction welding seam crystal particle from abnormal growth in heat process Download PDFInfo
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- CN1748927A CN1748927A CN 200510010420 CN200510010420A CN1748927A CN 1748927 A CN1748927 A CN 1748927A CN 200510010420 CN200510010420 CN 200510010420 CN 200510010420 A CN200510010420 A CN 200510010420A CN 1748927 A CN1748927 A CN 1748927A
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Abstract
The method of preventing aluminum alloy stirring friction welding seam crystal particle from abnormal growth in heat treatment belongs to the field of welding technology. The present invention controls the welding technological parameters to control the structure in the weld seam area and make the structure under weld state condition possess relatively high strain energy. The isometric crystal structure with relatively high strain energy forms fine crystal particle structure in the fallowing solid solution heat treatment owing to the increased nucleation particles. Therefore, controlling the weld technological parameters can avoid the abnormal growth of the weld seam area crystal particles in subsequent solid solution heat treatment.
Description
Technical field
The invention belongs to welding field, be specifically related to a kind of Aluminum Alloy Friction Stir Welding joint welding district crystal grain that prevents unusual method of growing up takes place in the post weld heat treatment process.
Background technology
The basic principle of agitating friction welding is as described in the European patent EP 0615480-B1, in stir friction welding process, utilize the stirring-head and the fricative heat of workpiece of rotation at a high speed to make the local plasticizing of materials to be welded, when stirring-head when weld interface moves forward, plastifying material is shifted to the rear portion by the front portion of stirring-head under the rotation friction effect of stirring-head, and forms fine and close solid phase weld seam under the extruding of stirring-head.Though adopt the method for agitating friction welding can realize that the softening problem of joint still exists than the more connection of high-quality of fusion welding method.Particularly for heat-treatable strengthened aluminium alloy, the reduction of strength of joint is even more serious.In order to bring into play the high-intensity characteristics of heat-treatable strengthened aluminum alloy to greatest extent, postwelding solution heat treatment technology has been applied to the agitating friction welding field of this aluminium alloy, so that overcome the above problems.
The case that postwelding solution heat treatment technology can significantly improve Aluminum Alloy Friction Stir Welding member overall performance for example U.S. Pat 6802444-B1, US6168067-B1 and US6780525-B2 is described, and the intensity of member, hardness, corrosion resistance all are significantly improved after the heat treatment.But because the friction stir welding joint weld metal zone is made up of tiny equi-axed crystal, the unstability of equi-axed crystal in the solution treatment process causes crystal grain generation abnormality to be grown up.Patent WO2004104258-A1 points out that weld metal zone crystal grain can reach about 200 μ m after the heat treatment.So thick equi-axed crystal certainly will worsen the performance of joint, therefore must take effective measure to prevent that the abnormality that weld metal zone crystal grain takes place from growing up in heat treatment process, so that make postwelding solution heat treatment technology can be applied to agitating friction welding field better.
At present less about prevent that Aluminum Alloy Friction Stir Welding joint welding district crystal grain from the report of the method that abnormality grows up taking place in the postwelding solution treatment.European patent EP 1285707-A1 avoids this district that the problem of abnormal grain growth takes place in solution heat treatment subsequently by the method that presets the intermediate alloy floor in the weld metal zone, but does not set forth the effect that prevents grain growth in the patent.And also there is tangible weak point in this method.At first, European patent EP 1285707-A1 is difficult to find effective intermediate alloy layer when implementing, promptly allow to find, and how to prepare also is the individual problem to be solved that has; Secondly, the introducing of intermediate alloy layer can produce certain influence to stir friction welding process, even the butt welded seam shaping produces destruction; Once more, the intermediate alloy composition of introducing is different from materials to be welded, thereby formed composition of weld line is inevitable different with mother metal, and some performance that like this will butt welded seam causes adverse influence.
Summary of the invention
Prevent in the prior art that in order to solve Aluminum Alloy Friction Stir Welding joint welding district crystal grain from unusual method of growing up taking place have the problem that is difficult to carry out and influences the shortcoming of Weld Performance in the postwelding solution heat treatment, the present invention proposes a kind of aluminum alloy stirring friction welding seam crystal particle unusual method of growing up in heat treatment that prevents, it prevents that by the control welding condition Aluminum Alloy Friction Stir Welding joint welding district crystal grain from abnormality taking place grow up in postwelding solution heat treatment process.Method of the present invention not only can effectively be avoided the abnormality of the weld metal zone crystal grain phenomenon of growing up, and technology is simple, is easy to realize.
The present invention can realize by following steps: at first determine the stirring-head rotary speed, then, in the scope of the speed of welding of described stirring-head rotary speed correspondence, determine not produce the range of choice of the speed of welding of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type, at last, select the higher limit of above-mentioned scope as speed of welding aluminum alloy materials to be welded to be carried out the agitating friction welding, described aluminum alloy materials is the aluminum alloy materials that can heat-treat.
The present invention can also realize by following steps: at first determine speed of welding, then, in the scope of the stirring-head rotary speed of described speed of welding correspondence, determine not produce the range of choice of the stirring-head rotary speed of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type, select the lower limit of above-mentioned scope as the stirring-head rotary speed aluminum alloy materials to be welded to be carried out the agitating friction welding at last, described aluminum alloy materials is the aluminum alloy materials that can heat-treat.
The above-mentioned weld defect that do not produce is meant and guarantees that material fully plastifies and do not form the tunnel type cavity blemish in weld seam.The agitating friction welding that the inventive method is mentioned is meant that the stirring-head and the fricative heat of workpiece that utilize rotation at a high speed make the local plasticizing of materials to be welded, when stirring-head when weld interface moves forward, plastifying material is shifted to the rear portion by the front portion of stirring-head under the rotation friction effect of stirring-head, and forms fine and close solid phase weld seam under the extruding of stirring-head.
Determine the stirring-head rotary speed earlier or determine speed of welding earlier no matter be, the present invention (adopts the high weldering speed or the slow-speed of revolution by the method for control welding condition as far as possible under the prerequisite that does not produce weld defect, welding condition is meant speed of welding and stirring-head rotary speed) be controlled at the institutional framework of weld metal zone under the as-welded condition, make this regional organization's structure under as-welded condition, have higher strain energy; This equiaxed grain structure that contains the improved strain energy forms the institutional framework of small grains owing to increasing of forming core particle in solution heat treatment process subsequently.Therefore, can solve weld metal zone crystal grain by the method for controlling welding condition unusual problem of growing up takes place in the postwelding solution heat treatment.
Description of drawings
Fig. 1 be the stirring-head rotary speed be 800rpm, when speed of welding is 100mm/min, the 2219-O aluminium alloy carries out the cross sectional representation of conventional friction stir welding joint; Fig. 2 be the stirring-head rotary speed be 800rpm, when speed of welding is 400mm/min, the 2219-O aluminium alloy carries out the cross sectional representation of conventional friction stir welding joint; Fig. 3 be the stirring-head rotary speed be 800rpm, when speed of welding is 100mm/min, the 2219-T6 aluminium alloy carries out the cross sectional representation of conventional friction stir welding joint; Fig. 4 be the stirring-head rotary speed be 800rpm, when speed of welding is 260mm/min, the 2219-T6 aluminium alloy carries out the cross sectional representation of conventional friction stir welding joint; Fig. 5 is the cross sectional representation of the heat treatment state Aluminum Alloy Friction Stir Welding joint of Fig. 1; Fig. 6 is the cross sectional representation of the heat treatment state Aluminum Alloy Friction Stir Welding joint of Fig. 2; Fig. 7 is the cross sectional representation of the heat treatment state Aluminum Alloy Friction Stir Welding joint of Fig. 3; Fig. 8 is the cross sectional representation of the heat treatment state Aluminum Alloy Friction Stir Welding joint of Fig. 4; Fig. 9 is that the employing speed of welding is that 400mm/min, stirring-head rotary speed are the cross sectional representation of the heat treatment state 2219-O Aluminum Alloy Friction Stir Welding joint after 700rpm welds; Figure 10 is that the employing speed of welding is that 400mm/min, stirring-head rotary speed are the cross sectional representation of the heat treatment state 2219-O Aluminum Alloy Friction Stir Welding joint after 1200rpm welds.
The specific embodiment
The specific embodiment one: this specific embodiment is to realize by such method: at first determine the stirring-head rotary speed, then, in the scope of the speed of welding of described stirring-head rotary speed correspondence, determine not produce the range of choice of the speed of welding of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type, at last, select the higher limit of above-mentioned scope as speed of welding aluminum alloy materials to be welded to be carried out the agitating friction welding, described aluminum alloy materials is the aluminum alloy materials that can heat-treat.The above-mentioned weld defect that do not produce is meant and guarantees that material fully plastifies and do not form the tunnel type cavity blemish in weld seam; The scope of described stirring-head rotary speed is 100～6000rpm; The scope of the speed of welding of described stirring-head rotary speed correspondence is 50～2000mm/min.Among the present invention, the range of choice of parameter can be determined with experiment.
The specific embodiment two: this specific embodiment with the difference of the specific embodiment one is: it is aluminum alloy materials to be welded that this specific embodiment adopts the 2219-O aluminium alloy, it is of a size of 300mm * 100mm * 5mm, joint categories is butt joint, adopt the tapered thread stirring-head, the shaft shoulder diameter of stirring-head is 14mm (millimeter), mixing needle is long to be 4.8mm, the stirring-head rotary speed is 800rpm (revolutions per minute), the range of choice that determine do not produce the speed of welding of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type this moment is 100～400mm/min (a millimeter per minute), therefore, according to the specific embodiment one, the higher limit 400mm/min that selects above-mentioned scope is that speed of welding comes the 2219-O aluminum alloy materials is carried out the agitating friction welding.Other steps are identical with the specific embodiment one.The typical organization in the as-welded joint welding district of this specific embodiment as depicted in figs. 1 and 2; And the microstructure in post weld heat treatment attitude joint welding district as shown in Figure 5 and Figure 6, and described heat treated solid solubility temperature is 540 ℃, and temperature retention time is 32 minutes, and aging temp is 165 ℃, and temperature retention time is 18 hours.As can be seen from Figure 5, when speed of welding was 100mm/min, weld metal zone crystal grain took place obviously to grow up in heat treatment process, about 1000～2000 μ m (micron) of crystallite dimension; As can be seen from Figure 6, be under the situation of 400mm/min when speed of welding, the degree of growing up of weld metal zone crystal grain obviously reduces, about 20～40 μ m of average grain size.This explanation adopts the method for High Speed Welding can prevent effectively that the abnormality that weld metal zone crystal grain takes place from growing up in the postwelding solution heat treatment.
The specific embodiment three: this specific embodiment with the difference of the specific embodiment one is: this specific embodiment adopts the 2219-T6 aluminium alloy as aluminum alloy materials to be welded, it is of a size of 300mm * 100mm * 5mm, joint categories is butt joint, adopt the tapered thread stirring-head, stirring-head shaft shoulder diameter is 14mm, mixing needle is long to be 4.8mm, the rotary speed of stirring-head is 800rpm, the range of choice that determine do not produce the speed of welding of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type this moment is 100～260mm/min, therefore, according to the specific embodiment one, the higher limit 260mm/min that selects above-mentioned scope is that speed of welding comes the 2219-T6 aluminum alloy materials is carried out the agitating friction welding.Other steps are identical with the specific embodiment one.The as-welded joint welding district typical organization of this specific embodiment as shown in Figure 3 and Figure 4; And the microstructure in post weld heat treatment joint welding district as shown in Figure 7 and Figure 8, and described heat treated condition is identical with the heat-treat condition that the specific embodiment one is mentioned.As can be seen from Figure 7, when speed of welding was 100mm/min, weld metal zone crystal grain took place obviously to grow up in heat treatment process, and crystallite dimension reaches 500～1000 μ m; As can be seen from Figure 8, be under the situation of 260mm/min when speed of welding, the degree of growing up of weld metal zone crystal grain obviously reduces, about 10～20 μ m of average grain size.This explanation adopts the method for High Speed Welding can prevent effectively that the abnormality that weld metal zone crystal grain takes place from growing up in the postwelding solution heat treatment.
The specific embodiment four: this specific embodiment is to realize by such method: at first determine speed of welding, then, in the scope of the stirring-head rotary speed of described speed of welding correspondence, determine not produce the range of choice of the stirring-head rotary speed of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type, select the lower limit of above-mentioned scope as the stirring-head rotary speed aluminum alloy materials to be welded to be carried out the agitating friction welding at last, described aluminum alloy materials is the aluminum alloy materials that can heat-treat.The above-mentioned weld defect that do not produce is meant and guarantees that material fully plastifies and do not form the tunnel type cavity blemish in weld seam; The scope of described speed of welding is 50～2000mm/min; The scope of the stirring-head rotary speed of described speed of welding correspondence is 100～6000rpm.
The specific embodiment five: this specific embodiment with the difference of the specific embodiment four is: it is aluminum alloy materials to be welded that this specific embodiment adopts the 2219-O aluminium alloy, it is of a size of 300mm * 100mm * 5mm, joint categories is butt joint, adopt the tapered thread stirring-head, the shaft shoulder diameter of stirring-head is 14mm, mixing needle is long to be 4.8mm, speed of welding is 400mm/min, the range of choice that determine do not produce the stirring-head rotary speed of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type this moment is 700～1200rpm, therefore, according to the specific embodiment four, select the lower limit 700rpm of above-mentioned scope to come the 2219-O aluminum alloy materials is carried out the agitating friction welding for the stirring-head rotary speed.Other steps are identical with the specific embodiment four.The microstructure such as the Fig. 9 and shown in Figure 10 in the heat treatment state joint welding district of this specific embodiment postwelding, described heat treated condition is identical with the heat-treat condition that the specific embodiment one is mentioned.As can be seen from Figure 9, when the rotary speed of stirring-head is under the situation of 700rpm, phenomenon does not take place significantly to grow up in weld metal zone crystal grain, about 10～20 μ m of average grain size; As can be seen from Figure 10, when the rotary speed of stirring-head was 1200rpm, weld metal zone crystal grain took place obviously to grow up in heat treatment process, about 500～1000 μ m of crystallite dimension.This explanation adopts the method for slow-speed of revolution welding can prevent effectively that the abnormality that weld metal zone crystal grain takes place from growing up in the postwelding solution heat treatment.
Claims (9)
1, prevents aluminum alloy stirring friction welding seam crystal particle unusual method of growing up in heat treatment, it is characterized in that its at first definite stirring-head rotary speed, then, in the scope of the speed of welding of described stirring-head rotary speed correspondence, determine not produce the range of choice of the speed of welding of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type, at last, select the higher limit of above-mentioned scope as speed of welding aluminum alloy materials to be welded to be carried out the agitating friction welding, described aluminum alloy materials is the aluminum alloy materials that can heat-treat.
2, the aluminum alloy stirring friction welding seam crystal particle unusual method of growing up in heat treatment that prevents according to claim 1, the scope that it is characterized in that described stirring-head rotary speed is 100～6000rpm.
3, the aluminum alloy stirring friction welding seam crystal particle unusual method of growing up in heat treatment that prevents according to claim 1, the scope that it is characterized in that the speed of welding of described stirring-head rotary speed correspondence is 50～2000mm/min.
4, according to claim 1, the 2 or 3 described aluminum alloy stirring friction welding seam crystal particle unusual methods of growing up in heat treatment that prevent, it is characterized in that it adopts the 2219-O aluminium alloy is aluminum alloy materials to be welded, it is of a size of 300mm * 100mm * 5mm, adopt the tapered thread stirring-head, the stirring-head rotary speed is 800rpm, and the range of choice of determining not produce the speed of welding of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type is 100～400mm/min.
5, according to claim 1, the 2 or 3 described aluminum alloy stirring friction welding seam crystal particle unusual methods of growing up in heat treatment that prevent, it is characterized in that its employing 2219-T6 aluminium alloy is as aluminum alloy materials to be welded, it is of a size of 300mm * 100mm * 5mm, adopt the tapered thread stirring-head, the rotary speed of stirring-head is 800rpm, and the range of choice of determining not produce the speed of welding of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type is 100～260mm/min.
6, prevent aluminum alloy stirring friction welding seam crystal particle unusual method of growing up in heat treatment, it is characterized in that its at first definite speed of welding, then, in the scope of the stirring-head rotary speed of described speed of welding correspondence, determine not produce the range of choice of the stirring-head rotary speed of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type, select the lower limit of above-mentioned scope as the stirring-head rotary speed aluminum alloy materials to be welded to be carried out the agitating friction welding at last, described aluminum alloy materials is the aluminum alloy materials that can heat-treat.
7, the aluminum alloy stirring friction welding seam crystal particle unusual method of growing up in heat treatment that prevents according to claim 6, the scope that it is characterized in that described speed of welding is 50～2000mm/min.
8, the aluminum alloy stirring friction welding seam crystal particle unusual method of growing up in heat treatment that prevents according to claim 6, the scope that it is characterized in that the stirring-head rotary speed of described speed of welding correspondence is 100～6000rpm.
9, according to claim 6, the 7 or 8 described aluminum alloy stirring friction welding seam crystal particle unusual methods of growing up in heat treatment that prevent, it is characterized in that it adopts the 2219-O aluminium alloy is aluminum alloy materials to be welded, it is of a size of 300mm * 100mm * 5mm, adopt the tapered thread stirring-head, speed of welding is 400mm/min, and the range of choice of determining not produce the stirring-head rotary speed of weld defect according to the material of aluminum alloy materials to be welded and size and stirring-head type is 700～1200rpm.
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| CN102626824A (en) * | 2012-04-28 | 2012-08-08 | 沈阳航空航天大学 | Friction stir welding process for preparing high-performance aluminum alloy sheet |
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| CN103567625B (en) * | 2012-07-19 | 2017-04-12 | 住友轻金属工业株式会社 | Method for welding aluminum alloy part and aluminum alloy plate manufactured with method |
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| AU733140B2 (en) * | 1998-09-29 | 2001-05-10 | Hitachi Limited | A friction stir welding method |
| JP3459210B2 (en) * | 1999-11-24 | 2003-10-20 | 株式会社日立製作所 | Friction stir welding method |
| CN1311073A (en) * | 2000-02-21 | 2001-09-05 | 株式会社日立制作所 | Friction mixing welding method |
| JP3589930B2 (en) * | 2000-02-25 | 2004-11-17 | 株式会社日立製作所 | Friction stir welding method |
| CN1369336A (en) * | 2001-02-15 | 2002-09-18 | 株式会社日立制作所 | Friction stirring connecting method of structural body, structural body and extruded bar section |
| US6660106B1 (en) * | 2001-08-22 | 2003-12-09 | The Boeing Company | Methods of manufacture of spin-forming blanks, particularly for fabrication of rocket domes |
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| CN102626824A (en) * | 2012-04-28 | 2012-08-08 | 沈阳航空航天大学 | Friction stir welding process for preparing high-performance aluminum alloy sheet |
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