The Method Of Low Temperature Cold Brittle Phenomenon In Steel Silo
According to our long-term steel silo engineering practice, Steel Silo summed up a set of measures to prevent and eliminate low temperature cold brittleness of Steel Silo, which are based on a large number of theoretical test results and Steel Silo engineering experience, and Involving the Steel Silo design and processing of the installation and transportation of the various stages, the following companies to explain to you under the prevention and elimination of low-temperature cold billet phenomenon.
First, the choice of structural type:
1. Minimize the stress concentration caused by the structural type and the machining process.
2. Reduce the stress concentration area due to the thermal impact of welding caused by local plastic deformation, the composite cross-section of the components should ensure the integrity of its cross-section.
3. Try to use thin plate and so on. With the increase of the thickness, the stress in the thickness direction increases gradually and the position is in the three-way tension state, and the transition to the plane strain state gradually increases, which also improves the possibility of brittle failure of the steel box component. , The higher stress concentration of low carbon steel and low alloy steel components, the thickness should be limited to 40mm or less.
Second, the choice of steel: in the selection should consider the following factors:
The importance of components, component production and installation of the installation of temperature conditions and process conditions. Sometimes depending on the ultimate thickness of the steel used and the structural type of the component.
Third, reduce the stress concentration method:
Reduce the stress concentration method is to improve the anti-low temperature cold brittle performance point of view artificially adjust the stress state of the component. It is beneficial to reduce the change of the stress concentration structure structure to reduce the ductile-brittle transition temperature, that is, to reduce the risk of brittle crack.
Fourth, the impact of grain size: the finer the grain of steel, the better the toughness, can reduce the toughness and brittle transition temperature. The smaller the grain size in the steel, the shorter the slip line, the less the screw dislocations in the tissue and the longer cracks in the slippery surface. The stress is concentrated in the night and the crack is less likely to expand. So it can improve the toughness of steel.
V. PROCESSING AND INSTALLATION Technical Measures: Technical measures relating to the production of processing and installation processes are based on the following principles:
1. cold steel processing will lead to cold deformation, so the process is not allowed to make the steel too hard and crack, scratches and so on defects.
2. Try to eliminate welding defects in welds and other welds and connected components as far as possible.
3. No large thermoplastic deformation and residual stress left in the weldment during welding.