防飞溅剂对焊接过程的影响分析
Effect analysis of anti-spatter fluid on welding process
- 2023年53卷第6期 页码:111-116
DOI: 10.7512/j.issn.1001-2303.2023.06.16
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针对焊接防飞溅剂在实际应用中可能出现的使用过量或局部累积现象进行了表面堆焊试验研究,分析不同类型、累积量的防飞溅剂在焊接过程中的状态变化及其对焊接过程中熔池流动性、电弧稳定性以及焊缝成形的影响。结果表明,油基防飞溅剂累积量一旦大于0.045 mL/cm2,便会有部分防飞溅剂进入熔池,从而降低熔池的流动性,导致焊丝液态熔敷金属堆积在电弧的后方,同时防飞溅剂会与电弧直接接触。水基防飞溅剂在电弧高温和压力的作用下会向前推进并迅速挥发,即使累积量为0.227 mL/cm2仍不会进入熔池,因此并不会影响熔池的流动性。水基防飞溅剂对应的电弧稳定性明显优于油基防飞溅剂,特别是当累积量小于等于0.09 mL/cm2时,这种差距最为明显。两类防飞溅剂作用下,焊缝整体成形基本一致,仅焊缝熔深较无防飞溅剂的降低约0.5 mm,而焊缝余高和熔宽并无明显变化。
In order to study the effect of anti-spatter fluid overuse and accumulation during welding process, overlaying tests are implemented to analyze the state changes of different types and accumulation of anti-spatter fluid in the welding process and its effect on molten pool fluidity, arc stability and weld geometry. The results show that once the accumulated amount of oil-based anti-spatter fluid is greater than 0.045 mL·cm-2, some of the anti-spatter fluid will enter into the molten pool, which in turn reduces the fluidity of the molten pool, resulting in the accumulation of molten metal behind the arc, while the anti-spatter fluid will be in direct contact with the arc. The water-based anti-spatter fluid moves forward and evaporates rapidly under the arc heat plus pressure and does not enter into the molten pool even at accumulation of 0.227 mL·cm-2, thus it has no influence on the fluidity of the molten pool. The arc stability of the water-based anti-spatter fluid is significantly better than that of the oil-based anti-spatter fluid, especially when the accumulated amount is less than 0.09 mL·cm-2. Under the influence of two types of anti-spatter fluids, the overall weld geometry is basically the same and only weld penetration is about 0.5 mm lower than that without anti-spatter fluids, while the weld reinforcement and width have no evident changes.
anti-spatter fluid;
molten pool fluidity;
arc stability;
weld geometry
焊接飞溅一直是实际焊接生产中的难题,既降低了焊丝的熔敷效率,同时也因焊后清理而降低了工作效率[
Kiszka A等人[
由此可见,虽然国内外研究人员对焊接防飞溅剂进行了深入研究,但这些研究主要关注防飞溅剂的应用效果及其对焊缝缺陷和力学性能的影响,并没有深入研究防飞溅剂的状态变化及其对焊接过程的影响。另外,这些研究仅针对防飞溅剂正常喷涂或稍有过量的情况,而忽视了实际使用过程中防飞溅剂过量使用以及在特定结构和位置中可能出现的局部累积现象。因此本文针对油基和水基两种焊接防飞溅剂,采用表面堆焊形式研究焊接过程中防飞溅剂的状态变化及其对熔池流动性、电弧稳定性及焊缝成形的影响。
选用尺寸6 mm×175 mm×50 mm的Q355B板材作为试验材料,焊前经喷砂和酒精擦拭处理。填充材料选择直径1.2 mm的SLD ER50-6焊丝,母材和焊丝的化学成分如
材料 | C | Mn | Si | S | P |
---|---|---|---|---|---|
Q355B | 0.17 | 1.09 | 0.25 | 0.002 | 0.012 |
SLD ER50-6 | 0.07 | 1.45 | 0.88 | 0.012 | 0.011 |
图1 防飞溅剂均匀铺展的焊接试板
Fig.1 Test plate with uniform anti-spatter fluid
为了减少人为因素的干扰,选择自动活性气体保护焊。焊接系统由发那科机器人工作站和福尼斯TPS5000焊接电源组成,焊接试验参数见
试验形式 | 焊接电流 /A | 焊接电压 /V | 焊接速度 /(mm·min-1) | 干伸长 /mm | 防飞溅剂累积量 /(mL·cm-2) |
---|---|---|---|---|---|
表面堆焊 | 250 | 32 | 360 | 18 |
0.045,0.09,0.136, 0.182,0.227 |
图2 防飞溅剂焊接试验设备系统
Fig.2 Welding test equipment system of anti-spatter fluid
相同电弧状态下不同类型、累积量防飞溅剂在焊接过程中的状态变化如
图3 不同类型、累积量防飞溅剂在焊接过程中的状态变化
Fig.3 State changes during welding process for different styles and accumulation of anti-spatter fluid
另外,由
由于原始的电流波形包含太多的噪声,严重影响对电弧稳定性的分析,因此使用
In=In-1×factor+In×(1-factor) | (1) |
图4 不同类型、累积量防飞溅剂对应的电流波形
Fig.4 Current wave pattern for different styles and accumulation of anti-spatter fluid
另外,焊接电压-电流图(U-I图)在一定程度上反映了电弧燃烧时电压和电流工作点轨迹的集中程度,因此也可以用于分析电弧的稳定性,不同类型、累积量防飞溅剂在表面堆焊过程中对应的U-I图如
图5 不同累积量的油基防飞溅剂对应U-I图
Fig.5 U-I diagram for different accumulation of oil-based anti-spatter fluid
图6 不同累积量的水基防飞溅剂对应U-I图
Fig.6 U-I diagram for different accumulation of water-based anti-spatter fluid
综合电流波形图和U-I图可以看出,水基防飞溅剂对应的电弧稳定性要明显优于油基防飞溅剂,特别是当累积量小于等于0.09 mL/cm2时,这种差距最为明显。对于油基防飞溅剂,当累积量小于等于0.182 mL/cm2时,其对应电弧的稳定性无明显变化,但是当累积量达到0.227 mL/cm2时,由于电弧不再直接与防飞溅剂接触,因此电弧稳定性稍有提升。而对于水基防飞溅剂,当累积量大于0.136 mL/cm2时,电弧波动逐渐增加,但当累积量为0.227 mL/cm2时,电弧波动性再次降低。由图
图7 不同类型、累积量防飞溅剂对应的表面堆焊焊缝成形
Fig.7 Overlaying weld appearance for different styles and accumulation of anti-spatter fluid
图8 油基防飞溅剂对应表面堆焊收弧位置的孔洞缺陷
Fig.8 Crater defect in ending position of overlaying weld for oil-based anti-spatter fluid
截取表面堆焊试板并测量焊缝的宏观金相,得到各焊缝的具体尺寸如
图9 不同类型和累积量防飞溅剂对应焊缝尺寸
Fig.9 Weld geometry for different styles and accumulation of anti-spatter fluid
本研究考虑了实际生产中焊接防飞溅剂使用过量和局部累积的情况,对比分析了两类防飞溅剂在不同累积量情况下的状态变化及其对焊接过程的影响,结果如下:
(1)油基防飞溅剂在电弧作用下的移动和挥发能力较弱,当累积量超过0.045 mL/cm2时,便会有部分防飞溅剂进入熔池,进而降低熔池的流动性,导致焊丝液态熔敷金属堆积在电弧的后方,同时防飞溅剂会与电弧直接接触。相比之下,水基防飞溅剂在电弧高温和压力的作用下会向前推进并迅速挥发,即使累积量达到0.227 mL/cm2时仍不会进入熔池,因此并不会影响熔池的流动性。
(2)水基防飞溅剂对应的电弧稳定性明显优于油基防飞溅剂,特别是当累积量不大于0.09 mL/cm2时,这种差距最为明显,同时电弧的波动性会随着累积量的增加呈现一定规律的变化。
(3)两类防飞溅剂作用下,焊缝整体成形基本一致,除焊缝熔深显著降低外,焊缝余高和熔宽无明显变化。但是对于油基防飞溅剂,当累积量达到0.182 mL/cm2,焊缝表面出现大颗粒飞溅,而当累积量达到0.227 mL/cm2时,熔池流动性受到严重影响,导致试板在收弧处出现深度为2 mm的孔洞。
从研究结果可以看出,制造商应尽量选用对焊接过程影响较小的水基防飞溅剂,同时做好焊工的培训和管理工作,避免在防飞溅剂显著过量的情况下进行焊接。
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