120 + Interview Questions in Molding And Core Sands in Casting-Forming-Welding I Page 3 InterviewSolution

101.	The attraction of clay minerals with water is a surface phenomenon which is called absorption.(a) True(b) FalseI got this question in an interview.Enquiry is from Fire Clays, Illite and Kaolinite topic in division Molding and Core Sands of Casting-Forming-Welding I
Answer» Right answer is (b) False To explain: Clay MINERALS have the ability to ATTRACT water particles and this attraction is a surface phenomenon which is CALLED as ADSORPTION, which is completely different from absorption process because the IONS and water molecules do not get inside the clay particles and they remained to adhere to the clay grains, that’s why the process is called as adsorption.

Discussion

102.	What is the percentage composition of quartz in Western bentonite?(a) 5%(b) 10%(c) 15%(d) 20%The question was asked by my school teacher while I was bunking the class.Question is from Molding Sands Binders topic in division Molding and Core Sands of Casting-Forming-Welding I
Answer» Correct CHOICE is (b) 10% Easiest EXPLANATION: Bentonite is classified into 2 types, NAMELY, Sodium montmorillonite and Calcium montmorillonite. Western bentonite ALSO CALLED Sodium montmorillonite is known to have a percentage composition 10% of quartz.

Discussion

103.	Which of the following percent of carbon is correct for Eutectoid steel (at 723^oC in Fe3-C diag)?(a) 0.05%(b) 0.5%(c) 0.6%(d) 0.8%I got this question in unit test.The above asked question is from Mold Materials in chapter Molding and Core Sands of Casting-Forming-Welding I
Answer» Right choice is (d) 0.8% To explain I WOULD SAY: At 723^oC in Fe3C diagram the TRANSFORMATION change takes place. The CARBON content at this point is 0.8% and is called as eutectoid STEEL.

Discussion

104.	A form of cast iron in which free carbon is present in the form of nodules in the matrix of cementite and ferrite. This form of cast iron is ____________(a) Malleable iron(b) Pig iron(c) Wrought iron(d) None of theseI had been asked this question in an international level competition.I'm obligated to ask this question of Mold Materials topic in division Molding and Core Sands of Casting-Forming-Welding I
Answer» The correct choice is (a) Malleable IRON The explanation: Malleable iron is ONE TYPE of cast iron in which free carbon is present in the form of nodules in the matrix of cementite and FERRITE.

Discussion

105.	Which of the following material is not used for mold making?(a) Iron(b) Zinc(c) Mild steel(d) Alloy steelI got this question in quiz.The origin of the question is Mold Materials topic in section Molding and Core Sands of Casting-Forming-Welding I
Answer» Right choice is (B) Zinc To explain: Zinc (Zn) has a very low MELTING POINT, making it non-dependable material to be USED as the material for mold making.

Discussion

106.	In magnesium alloys, what is the bentonite percentage composition?(a) 1%(b) 2%(c) 3%(d) 4%The question was asked in quiz.Question is from Molding Sand Mixtures for Casting in division Molding and Core Sands of Casting-Forming-Welding I
Answer» Correct choice is (d) 4% BEST explanation: In magnesium ALLOYS, the bentonite percentage composition is CALCULATED to be 4%. Whereas, in the CASE of GREEN sands, the bentonite percentage is recorded to be around 3.5%.

Discussion

107.	The figure below shows which foundry sand grain shape?(a) Round(b) Sub angular(c) Angular(d) CompoundThis question was addressed to me during an interview.The above asked question is from Molding Sands in portion Molding and Core Sands of Casting-Forming-Welding I
Answer» CORRECT ANSWER is (a) Round Best EXPLANATION: NONE.

Discussion

108.	Which of the following is not a type of moulding sand?(a) Red sand(b) Natural sand(c) Synthetic sand(d) Loam sandI got this question in an online quiz.This intriguing question originated from Molding Sands in section Molding and Core Sands of Casting-Forming-Welding I
Answer» Right option is (a) Red sand For EXPLANATION I would say: Red sand is not counted among the moulding SANDS, WHEREAS natural sand, synthetic sand and LOAM sand are various other TYPES of moulding sand, which can be effectively used for casting processes.

Discussion

109.	What is the percentage composition of water in natural sands?(a) 2-4%(b) 5-8%(c) 6-9%(d) 10-13%The question was posed to me in final exam.This is a very interesting question from Molding Sands in portion Molding and Core Sands of Casting-Forming-Welding I
Answer» The correct answer is (b) 5-8% The BEST I can explain: Water is an IMPORTANT agent used in sands, but its composition should be inside the DESIRED range. The percentage composition of water in natural sands is around 5-8% for mixing before MAKING a mould.

Discussion

110.	Nitriding process is used to increase surface hardness for which of the following materials?(a) Alloy steels(b) Low carbon steels(c) Medium carbon steels(d) High carbon steelsThis question was addressed to me in an interview for job.Query is from Mold Materials topic in portion Molding and Core Sands of Casting-Forming-Welding I
Answer» The CORRECT choice is (a) Alloy steels Explanation: Alloy steels ( DUE to low carbon CONTENT) can EASILY UNDERGO nitriding process.

Discussion

111.	Which of the following is a perfect composition of clay (Bentonite) used in moulding sand?(a) Al2O3(b) Al2O3.2SiO2(c) Al2O3.2H2O(d) Al2O3.2SiO2.2H2OI had been asked this question in an interview for job.Asked question is from Mold Materials topic in section Molding and Core Sands of Casting-Forming-Welding I
Answer» Correct CHOICE is (d) Al2O3.2SiO2.2H2O For EXPLANATION: Bentonite is one type of clay used in moulding sand as a BINDER. Its CHEMICAL formula is represented as Al2O3.2SiO2.2H2O.

Discussion

112.	Which of the following non-metallic material is not used in the synthesis of molds?(a) Magnesite(b) Silimanite(c) Zircon(d) Valcanised rubberI have been asked this question by my school principal while I was bunking the class.I would like to ask this question from Mold Materials topic in chapter Molding and Core Sands of Casting-Forming-Welding I
Answer» Right option is (d) Valcanised rubber The explanation: Valcanised rubber has a very low REFRACTORINESS, hence, using valcanised rubber for making molds can cause damage to the mold CAVITY or METALLIC structure so formed.

Discussion

113.	In light to medium size malleable iron castings, lake sand constitutes of 30 parts.(a) True(b) FalseThe question was asked during an online exam.This interesting question is from Preparation of Core Mix in portion Molding and Core Sands of Casting-Forming-Welding I
Answer» The correct answer is (b) False Explanation: In light to medium size MALLEABLE iron CASTINGS, lake sand constitutes only 20 parts and BANK sand constitutes to 75 parts.

Discussion

114.	Palygorskite and sepiolite clay minerals generally have similar fibrous structures.(a) True(b) FalseI got this question during an interview.The above asked question is from Fire Clays, Illite and Kaolinite in chapter Molding and Core Sands of Casting-Forming-Welding I
Answer» Right option is (a) True For explanation I would say: Palygorskite and sepiolite clay minerals have similar FIBROUS structures or MORPHOLOGIES, but palygorskite shows more structural variety. Both the clay minerals are MAGNESIUM silicates, but palygorskite has less magnesium and more aluminium than sepiolite. Structurally, both the clay minerals include blocks and RIBBON like sheets extending in a SPECIFIC direction.

Discussion

115.	Which of the following types of clay mineral includes potassium in the layer structure?(a) Chlorite(b) Vermiculite(c) Illite(d) KaoliniteThe question was asked in class test.My question is taken from Fire Clays, Illite and Kaolinite in portion Molding and Core Sands of Casting-Forming-Welding I
Answer» Correct option is (C) Illite The explanation: Illite is a CLAY mineral which has potassium in the INTERLAYER structure. The size and coordination number of potassium are like that it FITS tightly in the hexagonal ring of oxygen of the tetrahedral sheets. This makes the structure a STRONG interlocking ionic bond which packs the individual layers together and restricts the water particles from immersing the interlayer site.

Discussion

116.	The layer structure of kaolinite mineral totally consists of three tetrahedral silicate sheets.(a) True(b) FalseThe question was asked in examination.I'm obligated to ask this question of Fire Clays, Illite and Kaolinite topic in division Molding and Core Sands of Casting-Forming-Welding I
Answer» Right answer is (B) False Best explanation: The kaolinite minerals NORMALLY include kaolinite, nacrite and halloysite which are the most common but IMPORTANT CLAY minerals in nature that are widely USED in industries. They consist one to one layered structure, in which each layer include one tetrahedral silicate sheet and one octahedral silicate sheet.

Discussion

117.	Kaolinite clay mineral generally adsorbs fewer ions than that of other clay minerals.(a) True(b) FalseThe question was posed to me in final exam.The doubt is from Fire Clays, Illite and Kaolinite topic in chapter Molding and Core Sands of Casting-Forming-Welding I
Answer» Right choice is (a) True Easy EXPLANATION: KAOLINITE clay mineral is a weathering PRODUCT of feldspars and it commonly has white and powdery appearance. Kaolinite NAME is derived from a region named kaolin in china using the local clay mineral. It is extensively used in ceramics industries because it is electrically balanced but ADSORBS fewer ions than that of other clay minerals.

Discussion

118.	What is mixed with natural sand to make it semisynthetic sand?(a) Bentonite(b) Barelelne(c) Cubane(d) PrismaneThe question was posed to me in unit test.Question is from Molding Sands in chapter Molding and Core Sands of Casting-Forming-Welding I
Answer» The correct choice is (a) Bentonite For explanation: The ADDITION of a MATERIAL LIKE bentonite in its sand form, is because of the need to enhance the sand properties. Bentonite is MIXED with natural sand to MAKE it semisynthetic sand and thus improving its properties.

Discussion

119.	Ganister is another name for which sand?(a) Magnesite(b) Zircon(c) Silica sand(d) DolomiteI had been asked this question in exam.I'd like to ask this question from Refractory Sands topic in chapter Molding and Core Sands of Casting-Forming-Welding I
Answer» Right option is (c) SILICA SAND The best I can explain: GANISTER is another name for silica sand. As, silica is OBTAINED from carbon-ferrous sandstone, also known as dinas.

Discussion

120.	Which of the following group of material type is used in mold making?(a) Metallic only(b) Non-Metallic only(c) Both metallic as well as non-metallic(d) Neither metallic nor non-metallicThe question was asked in unit test.I'm obligated to ask this question of Mold Materials in section Molding and Core Sands of Casting-Forming-Welding I
Answer» The correct answer is (c) Both METALLIC as well as non-metallic The explanation is: Both metallic as well as non-metallic materials are USED for MAKING MOLDS.

Discussion

Explore topic-wise InterviewSolutions in .

The attraction of clay minerals with water is a surface phenomenon which is called absorption.(a) True(b) FalseI got this question in an interview.Enquiry is from Fire Clays, Illite and Kaolinite topic in division Molding and Core Sands of Casting-Forming-Welding I

What is the percentage composition of quartz in Western bentonite?(a) 5%(b) 10%(c) 15%(d) 20%The question was asked by my school teacher while I was bunking the class.Question is from Molding Sands Binders topic in division Molding and Core Sands of Casting-Forming-Welding I

Which of the following percent of carbon is correct for Eutectoid steel (at 723^oC in Fe3-C diag)?(a) 0.05%(b) 0.5%(c) 0.6%(d) 0.8%I got this question in unit test.The above asked question is from Mold Materials in chapter Molding and Core Sands of Casting-Forming-Welding I

Which of the following material is not used for mold making?(a) Iron(b) Zinc(c) Mild steel(d) Alloy steelI got this question in quiz.The origin of the question is Mold Materials topic in section Molding and Core Sands of Casting-Forming-Welding I

In magnesium alloys, what is the bentonite percentage composition?(a) 1%(b) 2%(c) 3%(d) 4%The question was asked in quiz.Question is from Molding Sand Mixtures for Casting in division Molding and Core Sands of Casting-Forming-Welding I

The figure below shows which foundry sand grain shape?(a) Round(b) Sub angular(c) Angular(d) CompoundThis question was addressed to me during an interview.The above asked question is from Molding Sands in portion Molding and Core Sands of Casting-Forming-Welding I

Which of the following is not a type of moulding sand?(a) Red sand(b) Natural sand(c) Synthetic sand(d) Loam sandI got this question in an online quiz.This intriguing question originated from Molding Sands in section Molding and Core Sands of Casting-Forming-Welding I

What is the percentage composition of water in natural sands?(a) 2-4%(b) 5-8%(c) 6-9%(d) 10-13%The question was posed to me in final exam.This is a very interesting question from Molding Sands in portion Molding and Core Sands of Casting-Forming-Welding I

In light to medium size malleable iron castings, lake sand constitutes of 30 parts.(a) True(b) FalseThe question was asked during an online exam.This interesting question is from Preparation of Core Mix in portion Molding and Core Sands of Casting-Forming-Welding I

Palygorskite and sepiolite clay minerals generally have similar fibrous structures.(a) True(b) FalseI got this question during an interview.The above asked question is from Fire Clays, Illite and Kaolinite in chapter Molding and Core Sands of Casting-Forming-Welding I

Which of the following types of clay mineral includes potassium in the layer structure?(a) Chlorite(b) Vermiculite(c) Illite(d) KaoliniteThe question was asked in class test.My question is taken from Fire Clays, Illite and Kaolinite in portion Molding and Core Sands of Casting-Forming-Welding I

The layer structure of kaolinite mineral totally consists of three tetrahedral silicate sheets.(a) True(b) FalseThe question was asked in examination.I'm obligated to ask this question of Fire Clays, Illite and Kaolinite topic in division Molding and Core Sands of Casting-Forming-Welding I

Kaolinite clay mineral generally adsorbs fewer ions than that of other clay minerals.(a) True(b) FalseThe question was posed to me in final exam.The doubt is from Fire Clays, Illite and Kaolinite topic in chapter Molding and Core Sands of Casting-Forming-Welding I

What is mixed with natural sand to make it semisynthetic sand?(a) Bentonite(b) Barelelne(c) Cubane(d) PrismaneThe question was posed to me in unit test.Question is from Molding Sands in chapter Molding and Core Sands of Casting-Forming-Welding I

Ganister is another name for which sand?(a) Magnesite(b) Zircon(c) Silica sand(d) DolomiteI had been asked this question in exam.I'd like to ask this question from Refractory Sands topic in chapter Molding and Core Sands of Casting-Forming-Welding I