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• 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
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• Reasons for choosing Q690D steel

The Effect of Preheating Temperature on AH36 Ship Steel Hardness

AH36 ship steel has been widely used in the ship field because of its good comprehensive performance and weldability. Laser welding has the advantages of high efficiency, good forming, and high power, and can effectively weld ship steel structure parts.

However, due to the fast cooling rate of laser welding, a large amount of martensite is prone to appear in the laser welded joint. Martensite is a typical brittle hard phase. Excessive martensite content in the weld can easily lead to defects such as cold cracks, which affect Joint impact toughness and other mechanical properties. Studies have shown that the mechanical properties of welded joints can be effectively improved by preheating before welding.

By controlling the preheating temperature, the cold cracking resistance of AH36 ship steel welded joints is improved; through the pre-weld preheating process, the tensile shear load of resistance welded joints is increased by more than 7%, and the fracture of AH36 ship steel joints is improved form.

In order to effectively improve the performance of welded joints of AH36 ship steel, BBN studied the microstructure and distribution of joints under different preheating temperatures and the influence of preheating temperatures on the microhardness of joints through flat plate butt laser welding experiments, providing a theory for rationally optimizing welding processes in accordance with.