JNTU
JNTU B.Tech III ALLOY STEELS Previous Question Paper (February - 2023 - R18)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Write the effects of any two alloying elements in steel.
Answer
1. Chromium: Increases hardenability and provides corrosion and oxidation resistance by forming a protective oxide layer. 2. Nickel: Improves toughness and ductility, particularly at low temperatures, and promotes the formation of an austenitic structure.
How high strength packing steels are produced?
Answer
High strength packing steels, often referred to as dual-phase or high-strength low-alloy (HSLA) steels, are produced through controlled rolling followed by rapid cooling. This process refines the grain structure and introduces a microstructure of ferrite and martensite or bainite, which provides a superior combination of high tensile strength and good formability.
Draw the heat treatment cycle for bainitic steels.
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Mention the requirements for a low-carbon bainitic steel.
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Compare and contrast between pearlite and bainitic steels.
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Write about thermo-mechanical treatments.
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Give the composition of Austenitic stainless steels.
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Write about Schaeffler diagram.
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What elements improve the heat resistance in steels?
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Write the composition of chromium hot work tool steels.
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Part B
List out the design criteria for the development of high strength low–alloy steels.
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Describe the structure-property relationship for low-carbon ferrite pearlite steels.
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Explain the production methods of HSLA steels.
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Describe the strengthening mechanisms involved in low-carbon bainitic steels.
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Compare and contrast between lower and upper bainitic steels.
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Explain the main characteristics of high – carbon bainitic steels and mention its limitations.
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Write a short notes on the effect of impact properties in low-carbon bainitic steels.
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Explain the structure property relationships in tempered martensite.
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Ausforming
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Cold drawn pearlitic steels
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Explain about precipitation stainless steels.
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Compare and contrast between duplex and austenitic stainless steels.
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What are the martensitic stainless steels? Explain the different types of martensitic stainless steels and their applications.
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Classify the tool steels with flow chart.
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Write the composition, heat treatment, mechanical properties, and applications of High Carbon High Chrome (HCHC) steels.
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Write the composition, heat treatment and resultant microstructure, mechanical properties, and applications of high chromium nickel austenitic alloys.
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