Common welding defects of welded pipes

Common welding defects of welded pipes are mainly the following:

1. Porosity
Porosity is the most common welding defect, which is formed by the inability of the gas in the weld to be completely released during the solidification process. Porosity will reduce the strength and sealing performance of the weld, and even cause the weld to rupture.

2. Slag inclusion

Slag inclusion is the failure to completely remove foreign matter such as impurities and oxides during welding, resulting in these impurities being sandwiched inside the weld. Slag inclusion will reduce the strength and sealing performance of the weld.

3. Cracks
During the welding process, cracks may appear in the weld due to the effect of thermal stress or other reasons. Cracks can cause the weld to break and reduce the strength and sealing performance of the weld.

4. Welding residual stress
During the welding process, thermal stress can cause certain residual stresses in the weld and the base material. This stress can affect the deformation and performance of the welded parts.

5. Pinholes
Pinholes are tiny pores that usually do not have a significant effect on the strength and sealing performance of the weld. However, when the pinhole density is large, the strength of the weld may be reduced.

6. Welding temperature is too high or too low
During the welding process, if the temperature is too high or too low, the weld may not be completely melted or melted unevenly, affecting the quality of the weld.

7. Weld deviation
The phenomenon that the weld deviates from the design position is called weld deviation. Weld deviation will affect the strength and sealing performance of the welded joint.

8. Unqualified weld size
If the weld size is too large or too small, the strength and sealing performance of the welded joint will be reduced.

9. Loose weld joint
The welded joint is not well combined, resulting in loose welds and low strength.

10. Welded joint is not firm
Failed to achieve sufficient welding strength during welding, and the joint is easy to loosen or fall off.

11. Welding deformation
During the welding process, the size or shape of the welded joint changes due to deformation caused by thermal expansion.

12. Uneven weld surface
During the welding process, the weld surface cannot be flattened, which affects the appearance and use effect.

The above are common welding defects of welded pipes. These defects will have a negative impact on the strength, sealing and durability of the welded pipes. Therefore, welding operators should strictly control welding parameters, check weld quality, and deal with welding defects in time during the welding process to ensure the quality and reliability of the welded joints.

Factors affecting weld quality:

Welds can be seen everywhere in our lives, from iron doors and fences at home to cars, ships, and even rockets. The quality of welds is the main factor to ensure their safety. Then, the most widely used manual arc welding is used as an example to illustrate the factors affecting weld quality.

1. Current size
If the current is too small, the weld is likely to be narrow and shallow, so that the weld strength does not meet the requirements.

If the current is too large, it is easy to burn the welded body, and it is more challenging for the welder's technical level. When welding steel bars with too large current, it is easy for the steel bars to be burned or even burned through. Therefore, the choice of current size should be appropriate.

2. Welding rod tilt angle

a. Excessive bevel
Excessive bevel of the welding rod angle will make the arc unstable, and obvious spatter will appear during welding. At the same time, the welding speed will also be affected, resulting in a decrease in welding quality.

b. Flat angle
The flat welding rod angle is generally considered to be the best angle. It can not only stabilize the arc, but also not affect the welding speed too much, while ensuring the appearance and quality of the weld.

c. Obtuse angle

The obtuse welding rod angle will produce a large amount of molten metal at the welding point, resulting in uneven welds and prone to defects such as cracks.

d. Sharp corners

The angle of the sharp welding rod will shorten the arc length and increase the molten metal at the welding point, resulting in quality problems such as weld deformation and deformation.

3. Welding speed

The welding speed should be appropriate and uniform. Too fast speed will lead to insufficient weld depth and width, and too slow speed will easily lead to burns. Uniform speed welding can ensure the overall quality and avoid pressure concentration caused by uneven speed.

4. Welding rod size

The size of the welding rod directly determines the choice and speed of the current. The larger the welding rod, the greater the current required, and the greater the current, the more difficult it is to control. Therefore, high-strength and high-quality welding requires extremely high technical level of welders.

The above are some basic factors that affect the quality of welds. Although welding technology is constantly updated and changed, for welders, it is important to improve their professionalism, but they should not forget to protect their own health.

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