• Improper welding of X80 pipeline may cause cracks
• Brief introduction of API X52 pipeline steel
• The difference between PSL1 and PSL2
• Harm of inclusions in X70 pipeline steel
• API 5L pipeline pipe
• X52 steel plate surface quality standards that need to be met
• The basic production process of API 5L X60 pipeline steel
• The key to Q460D steel welding process
• What does the heat treatment of Q690 Steel include?
• Reasons for choosing Q690D steel

The cracking causes of 20mm thick Q345B steel plate right angle bending

As a conventional product, Q345B steel plate has mature production technology, good comprehensive mechanical properties, welding performance and high cost performance. With the continuous development of economy and technology, Q345B steel plate is widely used in construction machinery, construction, automobile manufacturing and other industries.

MnS inclusions flow and deform together with the metal matrix along the rolling direction during the rolling process, and finally become strips or bands in the Q345B steel matrix. Due to the different ways of stress transmission between the inclusions and the Q345B steel plate matrix, under the action of external force, stress concentration will appear around the inclusions and become the source of cracks, resulting in brittle cracking.

Through the analysis of the right-angle bending cracking parts of 20mm thick Q345B steel plate using metallographic microscope, scanning electron microscope, energy spectrum analysis and other means, it was found that the reason for the right-angle bending cracking was MnS inclusions in the 1/4 and 1/2 parts of the steel plate thickness Aggregation and central segregation are caused.

Through corresponding effective measures such as controlling the sulfur content of molten steel, strengthening refining operations, strictly controlling the continuous casting process, and formulating a reasonable rolling process, the quality of the Q345B steel plate is ensured, thereby effectively avoiding the right-angle bending cracking of the Q345B steel plate.