How to fix the weld cracks

Date 06/05/2019

In the course of welding, welds are susceptible to defects and deformations if the welders fail to follow the proper procedure nor properly understand the metal properties of the welding material. The most common defects are cracked welds.

Weld cracking has many different causes so there are also many different fixes.

First determine the location of the weld crack: cracking, cracking or cracking along the welds, cracking in the weld or cracking in the middle of one of the welds.

Determination of crack properties: hot cracking or cracking.

Hot cracking is a defect that occurs during coagulation when the temperature is too high (over 1000 degrees Celsius).

Cold cracking usually occurs after finishing the welding process at temperatures below 1000 degrees centigrade. Cold cracking is harder to detect than hot cracking as it usually appears after several hours or even days.

Determine the size of the crack:

- Crude cracking: the texture can be destroyed as soon as the work. Can be detected with the naked eye or through the magnifying glass.

Microcrystalline cracks: This cracking will gradually spread and lead to the formation of rough crack. Only detectable by ultrasonic weld, magnetic, X-ray examination.

According to the shape of the crack:

1. vertical cracks:

Testing and detection methods:

+ Visual inspection.

+ Use the word powder

+ Use color indicator

+ X-ray, ultrasound

Causes and solutions

+ Formed by impurities with low melting point, concentrating on the center of welding when freezing

+ Use of materials for welding is not correct. »» »Selection of suitable welding materials.

+ In welding joints, there exists a large residual stress. »» »When welding, release the clamping forces for the welding joint. Increase the filling capacity of the welding material.

+ Speed too fast »» »Preheat for welding material, cool down by keeping heat for welding joint.

+ Incorrect weld joints. »» »Use a suitable welded, bevelled joint, reducing the gap between the welds.

+ Welds are not properly arranged. »» »Welds should be spaced apart.

2. Cracks in the area causing and closing the arc:

How to check and detect the above.

Causes and solutions:

The position of the arc is dented, there are many impurities. »» »Choosing the right welding equipment, can have a separate mode for attaching and closing the arc.

+ The arc protection is not good. »» In the beginning and end of the arc should use the technology connectors, so that the cracks outside the welding joint.

3. Horizontal cracking:

How to check and detect the above.

Causes and solutions:

+ Selection of improper welding materials. »» »Selection of suitable welding materials.

+ Speed of cool »» »Increase the current and size of welding electrodes.

+ Small welds compared to welding joints. »» »Preheat heating.

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