Pores in the weld seam are a common quality issue during robot welding. The presence of pores can lead to a decrease in the strength of welds, and even cause cracks and fractures. The main reasons for the formation of pores in robot welds include the following:
1. Poor gas protection:
During the welding process, the supply of protective gases (such as argon, carbon dioxide, etc.) is insufficient or uneven, which fails to effectively isolate oxygen, nitrogen, etc. in the air, resulting in gas mixing into the melt pool and the formation of pores.
2. Poor surface treatment of welding materials and base materials:
There are impurities such as oil stains, rust, moisture, and oxide scales on the surface of the welding material or base metal. These impurities decompose at high welding temperatures to produce gas, which enters the molten pool and forms pores.
3. Inappropriate welding process parameters:
If the current, voltage, and welding speed are too high or too low, resulting in insufficient stirring of the melt pool and the inability of gas to escape smoothly; Or if the blowing angle of the protective gas is improper, it may affect the gas protection effect.
4. Unreasonable weld design:
If the gap between the weld seams is too large, the fluidity of the molten pool metal is poor, and the gas is difficult to discharge; Or the shape of the weld seam is complex, and gas is not easy to escape at the depth of the weld seam.
5. High humidity in welding environment:
The moisture in the air decomposes into hydrogen gas at high welding temperatures, which has a high solubility in the molten pool and cannot escape in time during the cooling process, forming pores.
The measures to solve the problem of porosity in robot welds are as follows:
1. Optimize gas protection:
Ensure that the purity of the protective gas meets the standard, the flow rate is moderate, and the distance between the nozzle and the weld seam is appropriate, forming a good air curtain protection.
● Use appropriate gas composition and mixing ratio, such as using low or ultra-low hydrogen welding rods and wires, to reduce the source of hydrogen gas.
2. Strict surface treatment:
Thoroughly clean the surface of the welding material and base metal before welding, remove impurities such as oil, rust, and moisture, and perform preheating treatment if necessary.
For environments where moisture may occur during the welding process, take drying measures, such as using a weld seam dryer or preheating the workpiece.
3. Adjust welding process parameters:
Select the appropriate current, voltage, and welding speed based on the welding material, base material, and welding position to ensure moderate stirring and gas escape time of the molten pool.
Adjust the blowing angle of the protective gas to ensure that the gas evenly covers the weld seam.
4. Improve weld design:
Control the weld seam gap within a reasonable range to avoid being too large or too small.
For complex welds, methods such as segmented welding, preset filler metal, or changing the welding sequence can be used to improve gas discharge conditions.
5. Control welding environment:
Try to weld in a dry and well ventilated environment to avoid excessive humidity.
For environments where humidity cannot be controlled, measures such as using hygroscopics and welding seam heating can be considered to reduce the impact of moisture.
6. Monitoring and quality control:
Regularly check the performance of welding equipment, such as gas flow meters, welding gun nozzles, etc., to ensure their good working condition.
Real time monitoring of the welding process, such as using a welding process monitoring system, to promptly detect and adjust abnormal parameters.
Perform non-destructive testing (such as ultrasonic testing, radiographic testing, etc.) after welding to promptly detect and treat welds containing porosity. The comprehensive application of the above measures can effectively reduce the generation of pores in robot welds and improve welding quality.
The causes of porosity in robot welds include surface contamination of the welding material, insufficient gas protection, improper control of welding current and voltage, and excessive welding speed. To solve this problem, we need to take corresponding measures, including using clean welding materials, selecting protective gases reasonably and controlling flow rate, setting welding parameters reasonably, and controlling welding speed according to the situation. Only by simultaneously addressing multiple aspects can we effectively prevent and solve the problem of porosity in robot welds, and improve welding quality.
Post time: Apr-07-2024
