Method for detecting welding quality of Q345B seamless steel pipe

After the Q345B seamless steel pipe is welded, the thermal hardness test of the weld should be carried out. The evaluation standard is that the thermal hardness of the weld of the Q345B seamless steel pipe does not exceed 100 of the hardness of the base metal itself.

When inspecting the internal quality of Q345B seamless steel pipe welds, ultrasonic waves or radiation can be used, and the outer surface of the welds can be inspected by magnetic powder or penetrant and magnetic particle or penetrant. Q345B seamless steel pipes need to be thoroughly cooled and kept warm after welding. No matter which test method is used, it must meet the relevant requirements of the standard specification.

Check whether the weld appearance of Q345B seamless steel pipe meets the relevant requirements of the standard specification. At the same time, after each weld and heat treatment are completed, the Q345B seamless steel pipe weld should be inspected with a spectrum analyzer to see whether its chemical composition meets the relevant requirements. If Q345B seamless steel pipe does not meet the requirements, the cause should be found out in time and measures should be taken to deal with it.

When there are too many defects in the welded joints of Q345B seamless steel pipes, welding repairs can be used for repairing. Note that the number of times of welding and repairing alloy steel at the same position is not more than 2 times, and the following regulations must be met:
1. Defects must be completely eliminated;
2. When welding Q345B seamless steel pipes, corresponding measures need to be formulated and approved in strict accordance with the requirements of the repair process;
3. Re-appearance inspection and spectral analysis are required after rework;
4. Then heat-treat the joints of Q345B seamless steel pipes;
5. The repair service should carry out the necessary hardness test after the heat treatment of the Q345B seamless steel pipe;
6. After heat treatment, the reworked joint must be consistent with the original process flaw detection again.