Are there any significant risks in using cast iron for tunnel linings in an urban transit environment?
Main topic: Science
Short answer:
Cast iron is fragile and liable to brittle fracture. As a result of residual tensions in a cast product, linings subjected to loads far lower than the design loads may develop cold fractures. However, cast iron is much better than its next alternative steel with owing to its superior flowability and capability to fill a mold.
Components of cast iron[edit]
Cast iron is an alloy composed of iron, carbon, and as well as other components. The carbon percentage in cast iron surpasses 2.14 percent. Carbon increases cast iron's hardness but decreases its plasticity and ductility.[1] It can be classified by:
- Carbon condition
- Carbon spot form
- Type of metal base structure
- Chemical composition
The characteristics of the cast iron metal basis are comparable with steel and is more corrosion-resistant than steel.[2]
Risks of using cast iron in tunnel linings[3][edit]
- Cast iron is fragile and liable to fracture due to less elasticity.
- Taking into consideration the long transit and storage times, as well as the possibility of sensitive cast iron being damaged during transit to the installation site.
- The life cycle of cast iron has the possibility of causing defects, including hidden ones and those that are not identified visually by visual examination. These defects might possibly arise at any time.
- Phosphorus is an undesirable additive that significantly alters the characteristics of cast iron by decreasing its fluidity and increasing its cold brittleness.
- Lesser metal strength or flexibility increases the likelihood of cold fracture formation. For this reason, iron castings are more susceptible to cold cracking than steel castings.
- Casting product flaws needs to be reviewed in detail for the course of an integrated engineering assessment.
- Adding admixtures such as silicon, manganese, sulphur, and phosphorus to cast iron may change the mechanical characteristics of the material.
Cast Iron vs Steel[4][edit]
- Cast Iron has better abrasion resistance and anti-friction characteristics to steel.
- Cast Iron has rapid damping of both fundamental and resonant vibrations.
- The corrosion resistance of cast iron is higher than that of steel.
- Cast iron is made resistant to a variety of external stress concentrators, such as surface defects, notches, and grooves, by the presence of graphite.
Conclusion[edit]
As of 2022, components made of cast iron are believed to be a more advanced technology.[5]
References[edit]
- ↑ Oleinik, Pavel; Yurgaytis, Alexey (2017). "Optimization of the annual construction program solutions". MATEC Web of Conferences. 117: 00130. doi:10.1051/matecconf/201711700130. ISSN 2261-236X.
- ↑ Topchiy, Dmitriy; Tokarskiy, Andrey (2018). "Formation of the organizational-managerial model of renovation of urban territories". MATEC Web of Conferences. 196: 04029. doi:10.1051/matecconf/201819604029. ISSN 2261-236X.
- ↑ "Tunnelling and Underground Space Technology | Journal | ScienceDirect.com by Elsevier". www.sciencedirect.com. Retrieved 2022-10-06.
- ↑ "Reinforced Plastics Handbook | ScienceDirect". www.sciencedirect.com. Retrieved 2022-10-06.
- ↑ Topchiy, Dmitriy; Shatrova, Anastasia; Yurgaytis, Alexey (2018). "Integrated construction supervision as a tool to reduce the developer's risks when implementing new and redevelopment projects". MATEC Web of Conferences. 193: 05032. doi:10.1051/matecconf/201819305032. ISSN 2261-236X.