What are the measures to prevent layer tear of Z-direction steel

In the process of applying Z-direction steel, in order to give full play to the role of Z-direction steel and avoid lamellar tearing of Z-direction steel, many effective measures need to be taken. It is effective to select steel with resistance to lamellar tearing, reduce the content of inclusions in the steel and control the form of the inclusions, and increase the plasticity in the thickness direction of the steel plate.

In design and process, the following measures can be taken to avoid laminar tearing of the Z-direction steel.

1. One-sided welds should be avoided as much as possible, and double-sided welds should be used, so as to ease the stress state at the root of the welds and prevent stress concentration.

2. When the strength permits, try to use symmetric fillet welds with less welding volume instead of full weld penetration welds with large welding volume to avoid excessive stress.

3. Bevels should be made on the side subject to the Z-direction stress.

4. For T-shaped joints, a layer of low-strength deposited metal can be deposited on the horizontal plate in advance to prevent cracks in the root of the weld, and at the same time, the Z-direction stress of the horizontal plate can be relieved.

5. In order to prevent the layered tear of Z-direction steel caused by cold cracking, some measures to prevent cold cracking should be adopted as much as possible, such as reducing the amount of hydrogen, appropriately increasing the preheating, and controlling the temperature between the layers.