Mechanical Engineering Section D Machine Tool Practices Kibbe Section Materials What Numerical System Used Designate Carbon

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Machine Tool Practices, 11e (Kibbe)

Section D – Materials

1) What numerical system is used to designate carbon in alloy steels?

A) U.S.A.

B) SAE – ANSI

C) Color based

D) ISAE – AES

2) Three basic types of stainless steel are:

A) Tungsten-based, martensitic and ferritic

B) Electric, basic and open hearth

C) Troositic, martensitic and ferritic

D) Martensitic, ferritic and austenitic

3) Color coding is used as one means of identifying a particular type of steel. Its main

disadvantage is that there is no universal color-coding system.

4) In steel identification systems the first 3 digits represent the alloy used in the steel.

5) A 1040 steel would have 10 points of carbon.

6) List three shop tests that can be applied to determine what type of steel is in a particular part.

A) Scratch, file, spark, magnet, and machinability

B) Spectrometer analysis, residual deformation, hardness

C) Spark, radiographic, spectral

D) Microscopic grain etching, radiographic, acid sectioning

7) The letter “O” as assigned to tool steels designates:

A) Over stressed steel

B) Oil hardening steels

C) Steels that were made from selected ores

D) Ostenitic steels

8) The weight of one square foot of steel one inch thick is 40.80 lbs. A steel bar 1/2 inch thick ×

6 inches × 8 feet long is priced at $.95 per pound. What is the cost of the bar?

A) $38.76

B) $77.52

C) $273.60

D) $136.80

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Answer: B

9) The element chromium (Cr) is what makes stainless steels stainless.

10) The file hardness test is useful to determine:

A) The carbon content of steels

B) The machinability and relative hardness of metals

C) Brinell or Rockwell hardness numbers exactly

D) All of the above

11) Certain nonferrous metals are magnetic. Among these are:

A) Titanium

B) Aluminum

C) Copper

D) Nickel

12) When selecting steel, some things you should keep in mind are:

A) Age of steel, color

B) Pliability, friability and its amorphous structure

C) Hardenability, machinability and strength

D) Point of origin and lot number

13) A good construction material for high-strength, light weight, space vehicle parts would be:

A) Magnesium

B) Steel

C) Titanium

D) Zinc

14) What do the letter “T” and the letter “H” following the four-digit designation for aluminum

represent?

A) Solution heat treatment and strain hardening

B) Tested and strain hardened

C) Temper and heat treatment

D) Titanium alloyed with aluminum and hardened

15) How is magnesium different than aluminum?

A) Lighter

B) Brighter

C) Stronger

D) Heavier

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16) Which metal can be a fire hazard when being machined?

A) Babbit

B) Magnesium

C) Beryllium

D) Titanium

17) Copper wire is basically pure copper that has been hardened by:

A) Alloying with tin and zinc

B) Strain hardening

C) Precipitation hardening

D) Heating to 1200 deg. F. (649 deg. C.) and quenching in water

18) What does an alloy of tin and copper make, an alloy of zinc and copper?

A) High temperature solder and galvanizing compound

B) Bronze and die cast

C) Brass and bronze

D) Bronze and brass

19) Nickel is the metal used for:

A) Electric power lines

B) United States nickel coins

C) Electroplating

D) All of the above

20) Galvanizing and plating are familiar uses of zinc, lead and tin. On what base material are

these metals plated and what do they resist?

A) On babbitt bearings to resist wear

B) On die castings to resist deformation

C) On steel to resist corrosion

D) On pipe joints to resist leaking

21) Steels are often alloyed with planned amounts of nonferrous metal such as:

A) Molybdenum and tungsten

B) Hydrogen, nitrogen and oxygen

C) Sulfur, phosphorus and hydrogen

D) Aluminum and magnesium

22) Molding with high pressures uses various metals. What are these metals called?

A) Die cast

B) Permanent mold

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C) Investment casting

D) Babbitt type

23) If high carbon tool steel (about 1.0% carbon) is quenched from only 1200 degrees F. (649

deg. C.), what is the result?

A) Annealing of the metal

B) Martensite will form

C) No increase in hardness

D) None of the above

24) The severity of water quench sometimes causes:

A) One-inch thick sections to harden clear through

B) Bubbles to form inside the steel

C) Distortion and cracking

D) Lack of hardening in W1 steels

25) The greatest advantage of the carburizing process is that:

A) It hardens the material completely through

B) Low carbon steels can be made very hard on the surface only, while the core remains soft and

tough

C) It makes possible the hardening of thicker sections completely through while using an oil

quench to avoid distortion

D) A case-hardened part can remain as hard as Rc60 all the way through without the need for

tempering and still be just as hard as a similar tempered part

26) The correct temperature for quenching carbon steels is ________ degrees above the upper

critical limit?

A) 100

B) 50

C) 200

D) 1450

27) High carbon steel is tempered after being hardened to:

A) Anneal it

B) Give is a good color

C) Make the grains smaller

D) Toughen and soften it

28) If wrought iron or a very low carbon steel (.10 percent carbon) is quenched from a red heat

about 1500 F. (815 C.), it will:

A) Get hard

B) Crack or split

C) Need to be tempered

D) Remain soft

29) Which of the following would require the highest tempering temperature?

A) Steel cutting tools

B) Cold chisel

C) Spring steel part

D) Wood chisel

30) When a carbon steel cutting tool such as a drill is heated to a blue color, it has:

A) Been re-tempered and is softer

B) Been optimized

C) Been re-tempered and is harder

D) Not been affected all

31) After hardening, tempering should be done:

A) Within 24 hours

B) Time does not matter

C) Whenever time permits

D) Immediately

32) Furnaces used for heat treating steels are:

A) Puddling, soaking pit

B) Open hearth, Bessemer

C) Blast, Bessemer

D) Electric, gas

33) Carbon steel, when heated to high temperature in the presence of air, will:

A) Carburize

B) Decarburize

C) Harden only the surface

D) Rust

34) A soaking period at high temperature is needed to:

A) Completely carburize the surface of the metal so it will fully harden when quenched

B) Insure a complete mixture of austenite and martensite before quenching

C) Complete the dispersion of carbon atoms and equalize internal temperature

D) Convert a shallow hardening steel into a deeper hardening steel

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35) Agitating the part in the quenching medium:

A) Causes the steel to harden to a depth of only one inch

B) Causes warping and bending

C) Breaks down the vapor barrier for more rapid quenching

D) Prevents a fire from occurring

36) The heat treater maintains better control of the product by tempering:

A) After the part has been hardened for 24 hours

B) Before the part gets completely down to the Mf temperature

C) By the color method

D) In the furnace for a specified time

37) Quench cracks:

A) Appear blackened and run toward the center of the part

B) Cause the piece to crumble into small granules

C) Appear as a “chicken wire” network

D) None of the above

38) Quench cracks may be caused by:

A) Overheating

B) Wrong selection of steel

C) Time delay between quench and tempering

D) All of the above

39) Decarburization can be avoided in a furnace by:

A) Using an electric furnace

B) Having an oxidizing atmosphere

C) Laying the part on top of cast iron chips

D) Wrapping the piece in stainless foil

40) When grinding hardened steel, two kinds of surface failures are:

A) Porosity and discoloration from the quench medium

B) Changes in hardness on the surface and internal stresses

C) Decarburization and pitting

D) None of the above

41) When distortion must be kept to a minimum, which steel type should be used for hardening?

A) Oil hardening

B) Low carbon

C) Water hardening

D) Air hardening

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Answer: D

42) Castings and forgings with a non-uniform grain structure need to be:

A) Process annealed

B) Spherodized

C) Normalized

D) Annealed

43) Medium-carbon steels are often normalized to give them better machining qualities.

44) What type of grain structure is mostly affected by stress relief anneal?

A) All grains are recrystallized

B) Cold worked ferrite grain

C) Intermetallic compounds and martensite

D) Hard carbide and pearlite grains

45) The stress relief anneal temperature is:

A) 1000 F above the upper critical T line

B) 950 F.

C) Close to 1300 F.

D) 500 F above the upper critical T line

46) Process annealing is essentially the same as stress relief annealing.

47) What is sometimes done to high carbon steels to give them free machining qualities?

A) Spheroidizing

B) Normalizing

C) Stress relieving

D) Process annealing

48) What is the term used by the wire and sheet industry for stress relieving?

A) Spheroidize anneal

B) Full anneal

C) Normalizing

D) Process anneal

49) After heating to the normalizing temperature, how should the piece be cooled?

A) By quenching in oil

B) By cooling slowly in the furnace

C) By cooling to 1300 F, holding for several hours and then air cooling

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D) By cooling in still air

50) After heating to full the full annealing temperature, how should the piece be cooled?

A) By quenching in oil

B) By cooling in salts

C) By slowly cooling the furnace

D) None of the above

51) Low carbon steels that are spheroidized tend to be:

A) Free machining

B) Work hardening

C) More likely to produce good finishes

D) “Gummy”

52) The Rockwell and Brinell Hardness Testers utilize the specific property of hardness known

as:

A) Elastic hardness

B) Hardenability

C) Resistance to abrasion

D) Resistance to penetration

53) The Rockwell Hardness tester measures:

A) The amount of pressure required to penetrate to major depth

B) Wear

C) The rebound

D) The depth of penetration

54) When hardness increases, what else also increases?

A) Ductility

B) Plasticity

C) Tensile strength

D) Depth of penetration

55) What will happen to the Rockwell steel ball penetrator, if it is used for testing hard steels?

A) It will roll and cause the specimen to fly out

B) It will flatten and become inaccurate

C) It will become embedded in the specimen

D) None of the above

56) The Brinell hardness test is performed by applying two loads to a specimen and measuring

the depth of penetration in the specimen between the first, or minor, load and the major load.

57) On the Brinell tester, how much load should be used for testing steel?

A) 150 kg.

B) 3000 kg.

C) 10 kg.

D) 500 kg.

58) Which of the following penetrators should be used for testing thin brass?

A) “N” Brale

B) “C” Brale

C) “A” Brale

D) One sixteenth inch ball penetrator

59) Hardness is the ability to resist deformation and rupture when a load is applied.

60) The diamond spot anvil is used for:

A) Testing soft materials

B) Testing normalized materials

C) Superficial testing

D) Cylindrical surfaces

61) The test results can be affected by the specimen having:

A) Been tested too near the edge

B) A curved surface

C) Excessive roughness on the surface

D) All of the above