Select the false statement from the list provided?
Show answer Hide answer
Answer: A. aluminium in steel results in excessive grain growth
Explanation
Aluminum added to molten steel acts primarily as an effective deoxidizer and grain refiner. Rather than causing excessive grain growth, aluminum nitride precipitates restrict austenitic grain expansion. Therefore, claiming that aluminum results in excessive grain growth is demonstrably false. Grain refinement improves the overall mechanical strength and toughness of structural steels. Steelmakers intentionally add small quantities of aluminum during the final killing process. Other elements like manganese and nickel serve distinct alloying purposes in steel metallurgy.
Automotive and aerospace manufacturers demand fine-grained steels for reliable high-stress components. Controlling grain size during steel production prevents unexpected brittle fractures in service. Metallurgical testing verifies grain structure compliance before steel is approved for fabrication. Option B is true because manganese dissolves in iron to increase hardness and tensile strength. Option C is correct because nickel and chromium improve elasticity, resilience, and ductility. Option D is accurate because tungsten enhances magnetic properties and extreme wear hardenability.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Examine the following statements and select the correct one?
Show answer Hide answer
Answer: E. none of the above
Program Evaluation and Review Technique is specifically an event-oriented project management tool. Critical Path Method focuses primarily on activity durations and scheduling pathways. Since standard comparative statemen...
Q2. Select the correct comparative statement regarding Cornish and Lancashire boilers _______________?
Show answer Hide answer
Answer: D. lancashire has two fire tubes and cornish has one
A Lancashire boiler incorporates two internal fire tubes, whereas a traditional Cornish boiler contains only one. This dual-flue design in Lancashire boilers increases the internal heating surface area for enhanced steam...
Q3. Identify the incorrect assertion from the options below?
Show answer Hide answer
Answer: D. the arrows are drawn (to scale from) left to right
Project network arrows represent individual tasks but their physical lengths are not drawn to scale. Activity durations are indicated numerically alongside arrows rather than proportional to drawing lengths. Therefore dr...
Q4. Find the erroneous statement concerning the critical state of steam___________________?
Show answer Hide answer
Answer: D. this is the maximum pressure limit
The critical state marks the thermodynamic endpoint of the vapor-liquid coexistence curve rather than a maximum pressure limit. Engineering systems can operate at pressures well above the critical pressure in supercritic...
Q5. Choose the valid procedure step utilized when scheduling a project using the Critical Path Method__________________?
Show answer Hide answer
Answer: E. all of the above
CPM scheduling requires dividing complex projects into distinct manageable individual activities. Estimating required time durations and establishing logical task sequences are essential procedural steps. Constructing a...
Q6. Point out the incorrect statement when comparing water tube boilers to fire tube boilers ______________________?
Show answer Hide answer
Answer: E. chances of explosion are less in former case
Water tube boilers contain high-pressure water inside small tubes, making catastrophic explosions more dangerous or likely compared to shell-type fire tube boilers.