阅读说明：本技术 一种双主轴搅拌摩擦焊辅助热源焊接方法 (Auxiliary heat source welding method for double-spindle friction stir welding ) 是由 张会杰 刘旭 孙舒蕾 张豪 宋歌星 刘剑飞 张友民 于 2019-11-21 设计创作，主要内容包括：一种双主轴搅拌摩擦焊辅助热源焊接方法,所属焊接技术领域,焊接步骤：(1)准备待焊工件；(2)搅拌头安装定位；(3)焊接；(4)后处理。本发明采用辅助热源搅拌头和焊接焊缝搅拌头配合焊接,使高硬度金属材料与低硬度金属材料在厚度方向上可以同时达到塑性状态,从而使得焊接时的塑性金属流动、搅拌针更加充分,得到强度更高的焊接接头,且操作简单、可行度高,可适用于全位置焊接。(A welding method of an auxiliary heat source for double-spindle friction stir welding belongs to the technical field of welding and comprises the following welding steps: (1) preparing a workpiece to be welded; (2) installing and positioning a stirring head; (3) welding; (4) and (5) post-treatment. The auxiliary heat source stirring head and the welding seam stirring head are adopted to be matched for welding, so that the high-hardness metal material and the low-hardness metal material can simultaneously reach a plastic state in the thickness direction, the plastic metal flows and stirring pins are more sufficient during welding, a welding joint with higher strength is obtained, the operation is simple, the feasibility is high, and the welding seam stirring head is suitable for all-position welding.)

1. A double-spindle friction stir welding auxiliary heat source welding method comprises the following steps:

step 1, preparing a workpiece to be welded:

cleaning the surfaces of a high-hardness metal plate and a low-hardness metal plate, placing the high-hardness metal plate and the low-hardness metal plate on a workbench by adopting a butt joint method, and clamping and positioning the high-hardness metal plate and the low-hardness metal plate by using a special tool clamp to form a workpiece to be welded and a weld to be welded;

step 2, installing and positioning a stirring head:

installing and fixing an auxiliary heat source stirring head on an auxiliary heat source rotating main shaft, installing and fixing a welding seam stirring head on a welding seam rotating main shaft, then adjusting the positions of the auxiliary heat source rotating main shaft and the welding seam rotating main shaft to enable the auxiliary heat source stirring head to be positioned on a high-hardness metal plate, enabling the welding seam stirring head to be positioned on a welding seam of a workpiece to be welded, and finally respectively adjusting the auxiliary heat source stirring head and the welding seam stirring head to a welding starting point;

step 3, welding:

starting an auxiliary heat source stirring head, advancing towards the advancing direction of the welding seam stirring head along a straight line parallel to the welding seam, starting the welding seam stirring head to weld the welding seam when the auxiliary heat source stirring head advances to a distance of 25-50 mm from the starting point, upwards pulling the auxiliary heat source stirring head away from a workpiece when the auxiliary heat source stirring head advances to a distance of 20-40mm beyond the edge of the low-hardness metal plate, and then upwards pulling the welding seam stirring head away from the workpiece after the welding seam stirring head finishes welding the welding seam;

and 4, post-treatment:

and respectively detaching the auxiliary heat source stirring head and the welding seam stirring head from the rotating main shaft, detaching the welded workpiece from the workbench, and cutting off the part of the high-hardness metal plate, which exceeds the low-hardness metal plate.

2. The welding method of the auxiliary heat source for the friction stir welding with the double spindles as recited in claim 1, wherein in the step 1, the high-hardness metal plate and the low-hardness metal plate are made of metals and alloys thereof with a mohs hardness range of 2.5-6.5, such as aluminum, copper, titanium, and the like, and have a thickness range of 2-10 mm; the high-hardness metal plate is longer than the low-hardness metal plate along the direction of the weld joint to be welded.

3. The welding method of the auxiliary heat source for the double-spindle friction stir welding according to claim 1, wherein in the step 1, the welding seam to be welded is a straight line or a curve.

4. The welding method of auxiliary heat source for double spindle friction stir welding according to claim 1, wherein in step 2, the material of the auxiliary heat source pin and the welding seam pin is W18Cr4V, W6Mo5Cr4V2 or W9Mo3Cr4V brand high speed steel, or nickel based alloy, WC-Co alloy, polycrystalline cubic boron nitride, or the like, the material of the auxiliary heat source pin and the welding seam pin may be the same material or different materials, and when the material is different, the material hardness of the auxiliary heat source pin should be higher than the material hardness of the welding seam pin.

5. The welding method of auxiliary heat source for double-spindle friction stir welding according to claim 1, wherein in step 2, the shaft shoulders of the stirring head of the auxiliary heat source and the stirring head of the welding seam have a diameter of 10-35mm, and are shaped as a concave surface, an asymptotic groove, a flat surface, a concentric circular groove, a volute line, a spoke shape or a spiral line.

6. The welding method of auxiliary heat source for friction stir welding with double spindles according to claim 1, wherein in step 2, the pin is disposed on the pin of auxiliary heat source and the pin of welding seam, the pin has a tip diameter of 3-6mm, a root diameter of 4-10mm, a pin length of 1.5-10mm, and the pin has a left-handed or right-handed spiral shape.

7. The welding method of auxiliary heat source for friction stir welding with double spindles according to claim 1, wherein in the step 3, the auxiliary heat source pin and the welding bead pin are spaced apart from each other by 20 to 45mm in the welding direction (X coordinate direction) and 20 to 40mm in the direction perpendicular to the welding direction (Y coordinate direction) with respect to the table during the traveling.

8. The welding method of the auxiliary heat source for the friction stir welding with the double spindles as recited in claim 1, wherein in the step 3, the working parameters of the stirring head of the auxiliary heat source are as follows: the inclination angle is 0-3 degrees, the rotating speed is 500-2500r/min, the advancing speed is 10-1000mm/min, and the press-in amount of the shaft shoulder is 0.05-0.3 mm.

9. The welding method of the auxiliary heat source for the double-spindle friction stir welding according to claim 1, wherein in the step 3, the working parameters of the welding seam stirring head are as follows: the inclination angle is 0-3 degrees, the rotating speed is 500-2500r/min, the advancing speed is 10-1000mm/min, and the press-in amount of the shaft shoulder is 0.05-0.3 mm.

Technical Field

The invention belongs to the technical field of welding, and particularly relates to an auxiliary heat source welding method for double-spindle friction stir welding.

Background

Friction stir welding is a novel solid-phase welding method, and in the welding process, the welding temperature is lower than the melting point of a base metal, so that the problems of large residual stress, easy generation of air holes, large deformation degree and the like in the fusion welding process can be solved, and therefore, friction stir welding is widely applied to the welding process of aluminum alloy, copper alloy and magnesium alloy. With the development of industry, the application field of friction stir welding is continuously expanded, and the friction stir welding has a great application prospect in the connection of dissimilar metals such as aluminum-copper, aluminum-magnesium, aluminum-titanium and the like. However, in the friction stir welding process of welding a low-hardness metal material and a high-hardness metal material, the high-hardness material and the low-hardness metal material cannot simultaneously reach a plasticized state, so that the performance of a welded joint is reduced. At present, the prior art adopts a preheating mode for high-hardness metal materials to solve the problems.

Patent CN103008897A discloses a welding technique combining laser and friction stir welding. It is proposed to provide a preheating laser beam on the back of the welded plate; and the front surface is sequentially provided with a stirring head and a post-heating laser beam along the welding direction. The method can realize rapid high-quality welding, solves the problem of high-efficiency connection of the friction stir welding of the hard material welding plate, but is difficult to apply to complex and closed conditions; meanwhile, the laser preheating range is narrow, and the laser cannot be effectively preheated. Patent CN108907448A discloses a friction stir welding process for movably heating the back of a thick plate of aluminum-copper dissimilar metal. An auxiliary heating device mainly comprising an electromagnetic heating furnace is proposed, and the auxiliary heating device and a stirring pin move simultaneously through a guide rail to perform auxiliary heating on the copper plate. The design reduces the time difference between the friction heat in the stirring process and the time when two metals reach the plastic state, but the experimental device is complex. Patent CN104551379A discloses preheating a workpiece to be welded by using an arc, MIG, etc. as an auxiliary heat source. The method for adding the auxiliary heat source increases the service life of the stirring head by adopting electric arcs or plasma beams as the auxiliary heat source when welding high-melting-point materials and adopting MIG or MAG as the auxiliary heat source when welding dissimilar materials, but when welding aluminum alloy and high melting point, the metal side of the aluminum alloy is easier to reach a plastic state, so that the defect of adhesion is easier to generate.

Disclosure of Invention

In order to solve the technical problems, the invention provides an auxiliary heat source welding method for double-spindle friction stir welding, which enables a high-hardness metal material and a low-hardness metal material to simultaneously reach a plastic state in the thickness direction, thereby improving the performance of a welding seam, having the advantages of wide heating area and cost saving, and being capable of improving the quality of a joint and prolonging the service life of a stirring head for welding the welding seam. The specific technical scheme comprises the following steps:

step 1, preparing a workpiece to be welded:

cleaning the surfaces of a high-hardness metal plate and a low-hardness metal plate, placing the high-hardness metal plate and the low-hardness metal plate on a workbench by adopting a butt joint method, and clamping and positioning the high-hardness metal plate and the low-hardness metal plate by using a special tool clamp to form a workpiece to be welded and a weld to be welded;

step 2, installing and positioning a stirring head:

installing and fixing an auxiliary heat source stirring head on an auxiliary heat source rotating main shaft, installing and fixing a welding seam stirring head on a welding seam rotating main shaft, then adjusting the positions of the auxiliary heat source rotating main shaft and the welding seam rotating main shaft to enable the auxiliary heat source stirring head to be positioned on a high-hardness metal plate, enabling the welding seam stirring head to be positioned on a welding seam of a workpiece to be welded, and finally respectively adjusting the auxiliary heat source stirring head and the welding seam stirring head to a welding starting point;

step 3, welding:

starting an auxiliary heat source stirring head, advancing towards the advancing direction of the welding seam stirring head along a straight line parallel to the welding seam, starting the welding seam stirring head to weld the welding seam when the auxiliary heat source stirring head advances to a distance of 25-50 mm from the starting point, upwards pulling the auxiliary heat source stirring head away from a workpiece when the auxiliary heat source stirring head advances to a distance of 20-40mm beyond the edge of the low-hardness metal plate, and then upwards pulling the welding seam stirring head away from the workpiece after the welding seam stirring head finishes welding the welding seam;

and 4, post-treatment:

respectively detaching the auxiliary heat source stirring head and the welding seam stirring head from the rotating main shaft, detaching the welded workpiece from the workbench, and cutting off the part of the high-hardness metal plate exceeding the low-hardness metal plate;

the welding method of the auxiliary heat source for the double-spindle friction stir welding comprises the following steps:

in the step 1, the high-hardness metal plate and the low-hardness metal plate are made of metals and alloys thereof with Mohs hardness of 2.5-6.5 such as aluminum, copper, titanium and the like, and the thickness range is 2-10 mm; the high-hardness metal plate is longer than the low-hardness metal plate along the direction of the weld joint to be welded;

in the step 1, the welding seam to be welded is a straight line or a curve;

in the step 2, the auxiliary heat source stirring head and the welding seam stirring head are made of high-speed steel of W18Cr4V, W6Mo5Cr4V2 or W9Mo3Cr4V, or nickel-based alloy, WC-Co alloy, polycrystalline cubic boron nitride and the like, the auxiliary heat source stirring head and the welding seam stirring head can be made of the same material or different materials, and when the materials are different, the hardness of the auxiliary heat source stirring head is higher than that of the welding seam stirring head;

in the step 2, the diameters of the shaft shoulders of the auxiliary heat source stirring head and the welding seam stirring head are 10-35mm, and the shaft shoulders are concave, asymptote grooves, planes, concentric circular grooves, vortex lines, spoke shapes or spiral shapes;

in the step 2, stirring pins are arranged on the auxiliary heat source stirring head and the welding seam stirring head, the diameter of the end part of each stirring pin is 3-6mm, the diameter of the root part of each stirring pin is 4-10mm, the length of each stirring pin is 1.5-10mm, and each stirring pin is in a left-spiral or right-spiral shape;

in the step 3, the distance between the auxiliary heat source stirring head and the welding seam stirring head along the welding direction (X coordinate direction) is 20-45mm, and the distance perpendicular to the welding direction (Y coordinate direction) is 20-40mm relative to the workbench in the traveling process;

in the step 3, the working parameters of the auxiliary heat source stirring head are as follows: the inclination angle is 0-3 degrees, the rotating speed is 500-;

in the step 3, the working parameters of the welding seam stirring head are as follows: the inclination angle is 0-3 degrees, the rotating speed is 500-2500r/min, the advancing speed is 10-1000mm/min, and the press-in amount of the shaft shoulder is 0.05-0.3 mm.

Compared with the prior art, the auxiliary heat source welding method for the double-spindle friction stir welding has the beneficial effects that:

firstly, an auxiliary heat source stirring head rotates on a high-hardness metal plate at a high speed, so that the auxiliary heating effect on the high-hardness metal plate is achieved, and the speed of enabling the high-hardness metal plate at a welding seam to reach a plastic state is increased;

secondly, the welding seam stirring head rotates on the welding seam of the workpiece to be welded at a high speed, so that the high-hardness metal plate at the welding seam is promoted to further reach a plastic state, and the high-hardness metal and the low-hardness metal material are promoted to simultaneously reach the plastic state;

the auxiliary heat source stirring head and the welding seam stirring head are matched for use, so that the contact surfaces of the two metal plates can synchronously reach a plastic state, the plastic metal flows and stirring pins are more sufficient during welding, and a welding joint with higher strength is obtained;

and fourthly, the auxiliary heating method is simple to operate, high in feasibility and suitable for all-position welding.

Drawings

FIG. 1 is a schematic view of the installation and positioning of an auxiliary heat source stirring head and a welding seam stirring head: 1-high-hardness metal plate, 2-low-hardness metal plate, 3-auxiliary heat source stirring head, 4-welding seam stirring head, 5-auxiliary heat source rotating main shaft and 6-welding seam rotating main shaft;

fig. 2-4 are diagrams of the weld process stir head travel route of the present invention, wherein 1-a high hardness metal plate, 2-a low hardness metal plate, 5-the travel track of the auxiliary heat source stir head, and 6-the travel track of the weld joint stir head.

Detailed Description

The technical solutions in the embodiments of the present invention will be further described below with reference to fig. 1 to 4 of the present invention, but the present invention is not limited to these embodiments.

A double-spindle friction stir welding auxiliary heat source welding method comprises the following steps:

step 1, preparing a workpiece to be welded:

cleaning the surfaces of a high-hardness metal plate 1 and a low-hardness metal plate 2, placing the high-hardness metal plate and the low-hardness metal plate on a workbench by adopting a butt joint method, and clamping and positioning the high-hardness metal plate and the low-hardness metal plate by using a special tool clamp to form a workpiece to be welded and a welding line to be welded;

step 2, installing and positioning a stirring head:

installing and fixing an auxiliary heat source stirring head 3 on an auxiliary heat source rotating main shaft 5, installing and fixing a welding seam stirring head 4 on a welding seam rotating main shaft 6, then adjusting the positions of the auxiliary heat source rotating main shaft 5 and the welding seam rotating main shaft 6 to enable the auxiliary heat source stirring head 3 to be positioned on a high-hardness metal plate 1, enabling the welding seam stirring head 4 to be positioned on a welding seam of a workpiece to be welded, and finally respectively adjusting the auxiliary heat source stirring head 3 and the welding seam stirring head 4 to a welding starting point;

step 3, welding:

starting the auxiliary heat source stirring head 3 and advancing along a straight line parallel to the weld joint towards the advancing direction of the welding weld joint stirring head, as shown in FIG. 2; when the auxiliary heat source stirring head 3 moves to a distance of 25mm from the welding starting point, starting the welding seam stirring head 4, and welding the welding seam, as shown in fig. 3; when the auxiliary heat source stirring head 3 moves to a position 25mm beyond the edge of the low-hardness metal plate, the auxiliary heat source stirring head 3 is pulled upwards to leave the workpiece, and then after the welding seam stirring head 4 finishes welding seam welding, the welding seam stirring head 4 is pulled upwards to leave the workpiece, as shown in fig. 4;

and 4, post-treatment: respectively detaching the auxiliary heat source stirring head 3 and the welding seam stirring head 4 from the rotating main shaft, detaching the welded workpiece from the workbench, and cutting off the part of the high-hardness metal plate 1, which exceeds the low-hardness metal plate 2;

the welding method of the auxiliary heat source for the double-spindle friction stir welding comprises the following steps:

in the step 1, the high-hardness metal plate 1 is made of copper and has a thickness of 3.5 mm; the low-hardness metal plate 2 is made of aluminum and has the thickness of 3.5 mm; in the step 1, the high-hardness metal plate 1 is 30mm longer than the low-hardness metal plate 2 along the direction of the weld joint to be welded;

in the step 1, the welding seam to be welded is a straight line;

in the step 2, the auxiliary heat source stirring head 3 and the welding seam stirring head 4 are made of WC-Co alloy;

in the step 2, the shaft shoulders of the auxiliary heat source stirring head 3 and the welding seam stirring head 4 are 12mm in diameter and concave in shape;

in the step 2, stirring pins are arranged on the auxiliary heat source stirring head 3 and the welding seam stirring head 4, the diameter of the end part of each stirring pin is 3.5mm, the diameter of the root part of each stirring pin is 5.1mm, the length of each stirring pin is 3mm, and each stirring pin is in a right spiral shape;

in the step 3, the distance (X coordinate direction) along the welding direction is 25mm, and the distance (Y coordinate direction) perpendicular to the welding direction is 25mm relative to the workbench in the traveling process of the auxiliary heat source stirring head 3 and the welding seam stirring head 4;

in the step 3, the working parameters of the auxiliary heat source stirring head 3 are as follows: the inclination angle is 2.5 degrees, the rotating speed of the stirring head is 1000r/min, the welding speed is 50mm/min, and the press-in amount of the shaft shoulder during welding is 0.15 mm;

in the step 3, the working parameters of the welding seam stirring head 4 are as follows: the inclination angle is 2.5 degrees, the rotating speed is 1000r/min, the advancing speed is 50mm/min, and the press-in amount of the shaft shoulder is 0.15 mm.

The tensile strength of the welding joint which is not welded by the auxiliary heat source is about 124MPa, and the tensile strength of the welding joint of the auxiliary heat source of the friction stir welding in the embodiment can reach about 178 MPa.