MZCET/MECH/II A&B/ME6403/EMM/II 91 GAS CARBURIZING • Conveyor hearth furnaces make quenching in a controlled atmosphere possible. Find the diffusion coefficient for A into gas B. The microstructure of a hardened steel part is ferrite, martensite, or cementite. A Closer Look. Q8. A high temperature heat treatment process performed around A1, the aim of which is to make a material as soft as possible. Q.1 The correct order of the coordination number is SC, BCC, FCC and HCP unit cells is (A) 12, 8, 12, 6. It is often used to anneal metal, making it more malleable and flexible during the welding process. Filler material used for brazing is an alloy of (a) Copper andLead (b) Copper and Tin (c) Copper and Zinc and Lead Q.1 The correct order of the coordination number is SC, BCC, FCC and HCP unit cells is (A) 12, 8, 12, 6. Home MCQ Production Engg Manufacturing Technology-Joining, Machining and Metal Casting Processes - Set 06 ... Carburizing flame (B) Oxidizing flame (C) Oxy-acetylene flame (D) Neutral flame. Quick return. Learn Engineering Materials MCQ questions & answers are available for a Mechanical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. d) All of these . Maximum flame temperature in case of gas welding occurs at. Which one of the following temperatures is the actual, correct, exact temperature that officially separates brazing from soldering? He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, … 6. 100?C below critical temperature: D. Critical temperature: E. 30?C to 60?C above critical temperature View Answer Workspace Report Discuss in Forum. c) Nitriding. Keep in mind that pure Oxyacetylene is very susceptible to an explosion caused by pressure and temperature factors. 1) Flame hardening: In this method, oxyacetylene flame is used to heat the surface to it's critical temperature. a) Low. a) Carburizing. 12. 350°C to 450°C 4. A thin section of water hardening steel will air harden if you are not careful. The process consists of introducing the part to be carburized into the carburizing material for a stated time and at a stated temperature, depending upon the depth of case desired and the composition of the part. • The advantage over pack carburizing is an improved ability to quench from the carburizing temperature. d) Temperature . Comment * Related Questions on Workshop Technology. Carburizing, liquid salt or cyanide, nitriding or gas method. Usually by furnace cooling method, or isothermal in about 20 ℃ below Ar1 for a long time. (B) … b. inner cone. (C) 8, 6, 12, 12. b. Clapper box. 2. Brazing is done at the temperature of a) More than c b) Less than 450 C c) At 1000 c Soft soldering is done at the temperature of (a) More than 450 Oc (b) than 450 Oc (c) At Oc (d) At 1500 c (d) At 1500 Oc 450 O O O 34. The heating time should be increased ensuring that the core will also be fully transformed into austenite. (D) 6, 12, 12, 8. Medium temperature tempering C. High temperature tempering List-ll 1. Set - 2 Metallurgy Test - This test comprises 31 questions on Metallurgy. d. at the tip of the fame. For this reason, the Oxy-acetylene generator is limited to a maximum pressure of 5 atm. c. at the tip of the torch. Harikesh Yadav June 20, 2017 EE AND ECE MCQ PDF, General. 150°C to 250°C 2. 8. Which of the following is a case hardening process? MATERIAL SCIENCE 79 IMPORTANT EXPECTED MCQ PDF FOR VIZAG MT AND BEL PE EXAM 2017. 800F b. The part may then be quenched directly from the carburization temperature and tempered, or in some cases it must undergo a double heat treatment in order to ensure that both the … 8 9 P.T.O. Soaking time _____ with increase in section thickness and the amount of alloying elements a) decreases b) remains same c) increases d) none 33. A. Decreases with increase in gap between the two joining surfaces . C. Carburising. 118. Q10. In this method, surface layer gets austenatized because the temperature of flame is about 3000°C. T or F; It is important to know the stock allowance on parts prior to hardening because: It will help determine how much distortion is acceptable. MCQ (Single Correct Answer) GATE ME 2005. If the tearing efficiency of a riveted joint is 50%, then ratio of rivet hole diameter to the pitch of rivets is (A) 0.20 (B) 0.30 (C) 0.50 (D) 0.60. B. Oxidizing. Annealing / Normalising. Ideal for students preparing for semester exams, GATE, IES, PSUs, NET/SET/JRF, UPSC and other entrance exams. Annealing is a heat treatment process which alters the microstructure of a material to change its mechanical or electrical properties. The proper austenitizing temperature for hardening is typically 50º - 90ºC over the upper critical transformation temperature. 9. The strength of a brazed joint. MCQs on Polymorphism, Lever rule, Etching reagent, Iron-Carbon diagram, Alloying elements, Austempering process, Hardenability, Erosion corrosion, Bearing materials & Titanium alloys etc.1 mark is awarded … ANSWER: c. 450C — Metric (SI units) is the primary system of measurement in the world, and to comply with SI standards, AWS (in coordination with SI groups around the world) modified the definition of brazing back in the early … Remember there are three basic crystalline structures favored by metals: body-centered cubic (BCC), face-centered cubic (FCC), and hexagonal close packed (HCP). What is the process of heating a hardened steel to any temperature below the lower critical temperature, followed by any desired rate of cooling? b) Cyaniding. D. All of these. A. Normalizing B. Spheroidizing C. Carburizing D. Tempering 89. (D) 6, 12, 12, 8. Stage 3: Cooling the metal/alloy (i.e., quenching) at a rate necessary to obtain the desired properties. C. Decreases up to certain gap between the two joining surfaces beyond which it increases. The partial pressure of A at the surface of the liquid was 0.06 atm. The temperature was 25° C and the total pressure was maintained at 1 atm. Join The Discussion . Assume that gas B is insoluble in liquid A. In normalizing, one of the following statements is not correct. To test the above cooling rate, heat your part to above non-magnetic and put into your annealing medium (lime or vermiculite). B. 250°C to 350°C 3. Heated to the temperature which is 20 ~ 30 ℃ higher than Ac1, the holding time should not be too long, generally 2 ~ 4 hours. Engineering Materials MCQ question is the important chapter for a Mechanical Engineering and GATE students. Increases with increase in gap between the two joining surfaces . Carburizing depths of 0.1 to about 5 mm can be economically achieved with this method. The temperature varies but the cooling rate is the same for alloy tool steels. The temperature, thermal gradients and stress fields in the beam dump of the SARAF phase II Beam Dump (go to google) should withdraw power of … And while temperature is what controls these transformations, stress, cooling rate, and alloy or chemical composition can all influence the temperature at which the changes take place. View Answer. Since only the austenite structure is able to absorb sufficient amounts of carbon, the temperature during carburizing is above 900 °C with a carburizing time of several hours. 10. b. Flame 11. In shaper machine the time taken during the idle stroke is less as compared to forward cutting stroke and this is obtained by ___ mechanism. It can reduce the air hardening of low carbon martensitic stainless steel, avoid the hardening temper brittleness, and increase the creep strength. The process of inducing carbon to _____ Carbon steels in order to give it a hard surface is known as carburizing. carburizing flame is one with little oxygen, which produces a sooty, lower-temperature flame. Utilization of Electrical Energy MCQ PDF 1 Utilization of Electrical Energy is a important subject for RRB,SSC and others AE,JE & Technician exam,In this subject Today we are providing Electric Welding MCQ 1,In upcoming days we will cover Illumination, Electric heating,Electroplating, Electric drives and motors. Stage 1: Heating a metal/alloy beyond the critical temperature. The brass and bronze are welded by _____ flame. c) High. a. Q9. d) None . After heating, the surface is immediately quenched with water and cold base metal. A. Carburizing B. Annealing C. Normalizing D. Martempering 88. It ranges from 1400°F–2400°F (760°C–1316°C), depending on the alloy and carbon content. 1. • A material can be annealed by heating it to a specific temperature and then letting the material slowly cool to room temperature in an oven. (B) 6, 8, 12, 12. Neutral. In the carburizing and tempering alloy structural steel, it can increase hardenability while improving toughness and low-temperature performance of steel. Correct Answer. Match List-I (Temperature) with List-ll (Tempering) and select the correct answer using the codes given below the lists: List-I A. Home BEL MATERIAL SCIENCE 79 IMPORTANT EXPECTED MCQ PDF FOR VIZAG MT AND BEL PE EXAM 2020 MATERIAL SCIENCE 79 IMPORTANT EXPECTED MCQ PDF FOR VIZAG MT AND BEL PE EXAM 2020 Akash Yadav December 22, 2019. PART 2: MCQ from Number 51 – 100 Answer key: PART 2 PART 3: MCQ from Number 101 – 150 Answer key: PART 3 PART 4: MCQ from Number 151 – 200 Answer key: PART 4 T or F; Annealing, normalizing and hardening of a given steel are typically done at the same temperature. • The annealing process consists of heating the steel to or near the critical temperature (temperature at which crystalline phase change occurs) to make it suitable for fabrication. (C) 8, 6, 12, 12. a. next to the inner cone. Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry.He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. b) Medium. The temperature at which austentizing rapidly takes place depends upon the carbon content in the steel used. (B) 6, 8, 12, 12. Low temperature tempering B. On a small part it is easy to lose heat at too fast a rate and end up with a hard part without quenching. Case Carburizing •Heating of low carbon steel in carburizing medium like charcoal •Carbon atoms diffuse in job surface •Typical depth of carburisation; 0.5 to 5mm •Typical Temperature is about 9500C •Quenching to achieve martensite on surface and sub-surface •If needed, tempering to refine grain size and reduce stresses 9. 840F c. 450C. The molar flux of component A at the top of the test tube was found to be 1.6 × 10–3 kgmol/m2.h. Correct Answer . The temperature at which steel will harden. • In gas carburizing, the parts are surrounded by a carbon-bearing atmosphere that can be continuously replenished so that a high carbon potential can … Stage 2: Holding at that temperature for a sufficient period of time to allow necessary changes to occur. The temperature range of the solid carburizing in degree celsius ____ a) 750 – 850 b) 721 – 800 c) 925 – 950 d) 550 – 650 32. Ans: B … It produces thin and hard surfaces due to the transformation of austenite to martensite. A. 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