阅读说明：本技术 一种小功率大光斑激光-mag电弧复合堆焊方法 (Small-power large-light-spot laser-MAG arc composite surfacing welding method ) 是由 刘西洋 杨淼森 郭彦兵 张旺 方乃文 于 2019-11-08 设计创作，主要内容包括：本发明涉及一种小功率大光斑激光-MAG电弧复合堆焊方法,该方法包括如下步骤：(1)利用夹具将激光头与MAG焊枪固定；(2)调节激光束作用于被焊工件上的激光光斑尺寸至设定范围；(3)调节MAG焊枪位置,使得激光光斑入射点和焊丝轴线与被焊工件表面接触点的之间的距离在设定范围且激光光斑入射方向和焊丝轴线之间的夹角也在设定范围；(4)焊接过程中,调节激光功率和送丝速度,改变焊丝端头的熔化状态,使电弧形态由圆柱形向圆锥形变化；调节MAG电弧输出能量,减小熔池在母材厚度方向的熔化深度,增加熔池在母材表面的熔化面积。与现有技术相比,本发明实现小型空心辊类高效、高质量稳定堆焊,堆焊效率高。(The invention relates to a small-power large-light-spot laser-MAG arc composite surfacing method, which comprises the following steps: (1) fixing the laser head and an MAG welding gun by using a clamp; (2) adjusting the size of a laser spot of a laser beam acting on a welded workpiece to a set range; (3) adjusting the position of an MAG welding gun to ensure that the distance between the incident point of the laser spot and the contact point of the axis of the welding wire and the surface of the workpiece to be welded is in a set range and the included angle between the incident direction of the laser spot and the axis of the welding wire is also in the set range; (4) in the welding process, the laser power and the wire feeding speed are adjusted, the melting state of the end of the welding wire is changed, and the arc form is changed from a cylindrical shape to a conical shape; and adjusting MAG electric arc output energy, reducing the melting depth of the molten pool in the thickness direction of the parent metal, and increasing the melting area of the molten pool on the surface of the parent metal. Compared with the prior art, the invention realizes the efficient, high-quality and stable surfacing of the small hollow rollers and has high surfacing efficiency.)

1. A small-power large-light-spot laser-MAG arc composite surfacing method is characterized by comprising the following steps:

(1) fixing the laser head and an MAG welding gun by using a clamp;

(2) adjusting the size of a laser spot of a laser beam acting on a welded workpiece to a set range;

(3) adjusting the position of an MAG welding gun to ensure that the distance between the incident point of the laser spot and the contact point of the axis of the welding wire and the surface of the workpiece to be welded is in a set range and the included angle between the incident direction of the laser spot and the axis of the welding wire is also in the set range;

(4) in the welding process, the laser power and the wire feeding speed are adjusted, the melting state of the end of the welding wire is changed, and the arc form is changed from an MAG surfacing flat cylindrical shape to a laser-MAG arc composite surfacing conical shape; the MAG arc output energy is adjusted by utilizing the characteristic that the laser output power can be accurately controlled, the melting depth of a molten pool in the thickness direction of the base metal is reduced on the premise of ensuring that a welding wire is melted to provide deposited metal, and the melting area of the molten pool on the surface of the base metal is increased.

2. The small-power large-light-spot laser-MAG arc composite surfacing method according to claim 1, wherein the set range of the laser light spot size is 2-5 mm.

3. The small-power large-light-spot laser-MAG arc composite surfacing method according to claim 1, wherein the set range of the distance between the laser light spot incidence point and the contact point between the axis of the welding wire and the surface of the workpiece to be welded is 0-6 mm.

4. The small-power large-light-spot laser-MAG arc composite surfacing method according to claim 1, wherein the setting range of the included angle between the laser light spot incidence direction and the welding wire axis is 20-40 degrees.

5. The small-power large-light-spot laser-MAG arc composite surfacing method according to claim 1, wherein the composite surfacing is performed by consumable electrode open arc self-shielded flux-cored wire surfacing or consumable electrode gas shielded flux-cored wire surfacing.

6. The small-power large-light-spot laser-MAG electric arc composite surfacing method according to claim 1, wherein the welding wire comprises a C-Cr type flux-cored welding wire or a Ni-Cr type flux-cored welding wire, and the welding wire is determined according to the welding performance of a surfacing layer on the surface of a workpiece to be welded.

7. The small-power large-light-spot laser-MAG electric arc composite surfacing method according to claim 6, wherein when the surface surfacing layer of the workpiece is required to have high hardness, a C-Cr type flux-cored wire is used, and when the surface surfacing layer of the workpiece is required to have high corrosion resistance, a Ni-Cr type flux-cored wire is used.

8. The small-power large-light-spot laser-MAG arc composite surfacing method according to claim 1, characterized in that the optimal range of laser power is 0.5-2 kW, and the optimal range of wire feeding speed is 3-7 m-min^-1。

Technical Field

The invention relates to a composite surfacing method, in particular to a low-power large-light-spot laser-MAG electric arc composite surfacing method.

Background

At present, surfacing of the continuous casting roller mainly adopts traditional submerged arc welding and open arc self-shielded welding as main welding. Submerged arc overlaying has high deposition efficiency and low overlaying cost, but when overlaying a small-diameter continuous casting roller, the heat input is large, the axial shrinkage after welding is large, and the mechanical positioning size in the roller needs to be remachined, so the submerged arc overlaying is commonly used for the surface overlaying of the large-diameter (more than 180mm) continuous casting roller. The open arc self-protection surfacing has been designated as the main method of continuous casting roller surfacing by the austenitic steel union in recent years, in particular to surfacing of continuous casting rollers with medium and small diameters (140 mm and 180mm), because of simple equipment and process, convenient operation, high deposition efficiency, low dilution rate and small heat input, and gradually replaces submerged arc surfacing.

With the continuous development of continuous casting equipment and technology, the small hollow continuous casting roller has wider application in the metallurgical industry. When the small-sized hollow continuous casting roller (the diameter of the close packing roller is 100-120mm) is subjected to surfacing, the heat input, dilution rate and weld forming of open arc self-protection surfacing are not suitable, and during surfacing, a large heat influence is caused on a base material, so that the weld texture is loose, dendritic crystals are coarse, the small-sized hollow continuous casting roller is easily subjected to heat deformation, and the surfacing repair requirement of the small-sized hollow continuous casting roller is difficult to meet. The laser surfacing can accurately control heat input, has low dilution rate, easily causes stress imbalance because of high cooling speed of a molten pool, and easily generates cracks due to low toughness of a welded seam and a heat affected zone; meanwhile, the surfacing of the continuous casting roller not only comprises surface modification, but also comprises the restoration of mechanical dimension, needs laser multilayer surfacing, has lower efficiency and is not easy to carry out batch surfacing of the continuous casting roller. Therefore, no suitable surfacing method exists for surfacing of the small hollow continuous casting roller at present.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a small-power large-light-spot laser-MAG arc composite surfacing method.

The purpose of the invention can be realized by the following technical scheme:

a small-power large-light-spot laser-MAG electric arc composite surfacing method comprises the following steps:

(1) fixing the laser head and an MAG welding gun by using a clamp;

(2) adjusting the size of a laser spot of a laser beam acting on a welded workpiece to a set range;

(3) adjusting the position of an MAG welding gun to ensure that the distance between the incident point of the laser spot and the contact point of the axis of the welding wire and the surface of the workpiece to be welded is in a set range and the included angle between the incident direction of the laser spot and the axis of the welding wire is also in the set range;

(4) in the welding process, the laser power and the wire feeding speed are adjusted, the melting state of the end of the welding wire is changed, and the arc form is changed from an MAG surfacing flat cylindrical shape to a laser-MAG arc composite surfacing conical shape; the MAG arc output energy is adjusted by utilizing the characteristic that the laser output power can be accurately controlled, the melting depth of a molten pool in the thickness direction of the base metal is reduced on the premise of ensuring that a welding wire is melted to provide deposited metal, and the melting area of the molten pool on the surface of the base metal is increased.

The laser spot size setting range is 2-5 mm.

The set range of the distance between the laser spot incidence point and the contact point between the axis of the welding wire and the surface of the workpiece to be welded is 0-6 mm.

The setting range of an included angle between the incidence direction of the laser facula and the axis of the welding wire is 20-40 degrees.

When the composite overlaying is carried out, the surfacing with a consumable electrode open arc self-protection flux-cored wire or the surfacing with a consumable electrode gas protection flux-cored wire is adopted.

The welding wire comprises a C-Cr type flux-cored welding wire or a Ni-Cr type flux-cored welding wire, and the welding wire is determined according to the welding performance of a surfacing layer on the surface of a workpiece to be welded.

When the hardness of the surfacing layer on the surface of the workpiece to be welded is required to be high, the C-Cr type flux-cored wire is adopted, and when the corrosion resistance of the surfacing layer on the surface of the workpiece to be welded is required to be high, the Ni-Cr type flux-cored wire is adopted.

The optimal range of laser power is 0.5-2 kW, and the optimal range of wire feeding speed is 3-7 m.min^-1。

Compared with the prior art, the invention has the following advantages:

(1) in the process of the low-power large-light-spot laser-MAG electric arc hybrid pile, the MAG electric arc is mainly used for melting a welding wire to provide deposited metal and melting the surface of a base metal, and the application of the low-power large-light-spot is the key for realizing the efficient, high-quality and stable surfacing of the small hollow roller by the surfacing method. The effect of the device is that firstly, a small-power large light spot as a welding heat source is compounded with MAG electric arc, the MAG electric arc can be stabilized, the current variation coefficient is changed from 19.98 of MAG surfacing welding to 15.5 of MAG welding, and the current variation coefficient is reduced by 22%; secondly, the MAG arc space is changed, the arc action area is increased, and the melting surface area of the parent metal is increased; thirdly, actual output current of the MAG electric arc is weakened, and the melting depth in the thickness direction of the base metal is reduced; fourthly, when the same surfacing current is ensured for surfacing, stable surfacing with higher wire feeding speed can be realized by adding the laser, and smaller surplus height-fusion width ratio and dilution rate are obtained, so that the surfacing efficiency is obviously improved, the welding seam forming is improved, and the efficient and high-quality stable surfacing of small hollow rollers is realized.

(2) The small-power large-light-spot laser-MAG arc composite surfacing welding realizes efficient and high-quality stable surfacing welding of small hollow rollers. Compared with MAG arc surfacing, the residual height-fusion width ratio of a surfacing welding seam is reduced by 14%, the dilution rate is reduced by 20%, the width of a heat affected zone is reduced by 28%, and the deposition speed is increased by more than 40%. The current variation coefficient is changed from 19.98 of MAG surfacing welding to 15.5 of MAG welding, the current variation coefficient is reduced by 22 percent, and the stability of the surfacing welding process is obviously enhanced. The lath martensite characteristic of the composite surfacing welding seam is more obvious, the crystal of a heat affected zone is more uniform and fine, and the cross section of the welding seam has higher hardness.

Drawings

FIG. 1 is a schematic diagram of the process state of the small-power large-spot laser-MAG arc composite surfacing method.

In the drawing, 1 is a welding wire, 2 is a MAG arc, 3 is a surface overlay welding layer, 4 is a base material melting layer, 5 is a base material, 6 is a laser beam, and 7 is a laser spot.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. Note that the following description of the embodiments is merely a substantial example, and the present invention is not intended to be limited to the application or the use thereof, and is not limited to the following embodiments.