With the increasing market demand for titanium products, the problem of manufacturing costs has become increasingly prominent. In order to save the usage of the metal titanium, more and more large-size and thin-gauge titanium-steel composite plates are used in energy, petroleum, chemical, marine, mining, and other industries.
The large-thickness clad titanium-steel clad plates used in important fields in China are mostly produced by the explosive welding method, but the explosive clad plate produces residual stress after rolling, which seriously affects the physical and chemical properties of the clad plate, such as fatigue performance, dimensional stability, and corrosion resistance performance. Baoji Taicheng Clad Metal Materials Co., Ltd is a professional metal clad plate factory, today I will take you to explore the reasons for the cracks caused by the cold rolling of titanium steel clad plates.
The performance of the steel plate is tested after explosive composite, and the shear strength of the composite plate is 270MPa, and the bending performance is qualified. The composite board passed the flaw detection before cold rolling without any defects. After cold rolling, delamination defects appeared. The defect was located at the thickness layer of 16mm and the length was about 500mm, which was confirmed to be caused by the base metal.
The internal cracks existing in the steel plate are formed during the continuous casting process. Normally, they can be rolled by post-heat pressure processing. However, the internal cracks contain contaminated molten steel, which changes the internal chemical composition of the cracks, resulting in carbon, sulfur, and nitrogen. The content of such harmful elements increases sharply, forming abnormal structures in and around the cracks, and contains a large number of non-metallic inclusions. Even if the cracks are rolled during the hot rolling process, the local plastic toughness is greatly reduced, and the cracks are distributed in the thickness of the plate. 1/3 position. The closer the crack is to the surface, the less deformation the steel plate can withstand, and the greater the damage.
There are type A microscopic non-metallic inclusions in the steel plate, which destroy the continuity of the steel matrix and become the source of cracks during the explosive recombination process. In the process of metal explosive compounding, the base metal is subjected to high-speed and high-pressure impact, and severe plastic deformation occurs inside, which has high requirements on the impact toughness and plasticity of the steel plate, and the intermediate cracks and local composition changes in the steel reduce the steel. toughness and plasticity. The internal cracks in the steel plate have cracked and are perpendicular to the surface, indicating that the cracks are mainly formed during the explosive composite deformation process. Subsequent rolling and welding processes also deform the interior of the steel plate, allowing cracks to continue to grow. The preventive measures mainly improve the internal quality of the steel plate and the toughness index of the matrix by controlling the number of inclusions, so as to improve the plastic deformation resistance of the explosive composite plate and reduce the probability of cracks.
(1) When the base metal crack does not expand under force, the performance and flaw detection index of the composite plate can meet the standard requirements.
(2) The root cause of cold rolling cracks in titanium-steel clad plates lies in the presence of non-metallic inclusions (sulfides) in the steel, which destroy the continuity of the matrix and continue to expand the cracks in the subsequent rolling and welding processes. Taking preventive measures to control the number of inclusions and improve the toughness of the base metal can reduce the probability of cracks in the explosive clad plate.
If you have any questions or needs about metal composite plates, welcome to consult and cooperate! As a qualified titanium-steel composite plate manufacturer, we must provide you with high-quality products.
