Heat treatment

Question 1

XRD

Answer 1

X ray Diffraction. Read wavelenght to determine grain size and different phases

Question 2

Quenching

Answer 2

The procces where metal is cooled in some type of solution at a fast cooling rate. cooled through it’s eucteoid point.

Question 3

Temperature gradient

Answer 3

change in temperature

Question 4

Tempering

Answer 4

The procces to change the tempeture to increase toughness. rapid cooling

Question 5

Stress Relieve

Answer 5

Procces where you heat up to recyrazatioln and then cool down. Used to remove the different stresses, residual stresses, and inertial stresses as well as distortion.

Question 6

Hot rolling

Answer 6

Heated at recryzalation tempeture and then strecthed out to be put through two rollers. rolled out

Question 7

Surface Hardening

Answer 7

Proccess where the surface is treateeted to create a thin, wear resistance layer with increased harndess . the core remains soft and ductile . Done to increase hardness

Question 8

Homogenizing

Answer 8

Procces to reduce chemical segregation one element. allows for chemical diffusion involves heating near the metling point and then slowly cooling it.

Question 9

Spherodizing

Answer 9

results in nodules in grains turningign into spheres. results in high ductility.

Question 10

Normalizing

Answer 10

Done outside of the furnace. Increases formability.

Question 11

Ovens

Answer 11

Air ducts distribute heated air from separate heating chamber via recirculating fan. best at lower temperatures

Question 12

Annealing

Answer 12

The process involves heating the metal so that the metal as well as rearranges the structure of the metal. . Done to increase ductility.

Question 13

Quenching medium

Answer 13

The liquid material into which metal is plunged during the quenching. Process

Question 14

4 stages of quenching

Answer 14

Steam forming. Steam coverage. Steam

Question 15

Surface Hardening

Answer 15

Pro

Question 16

4 stages of vapor film

Answer 16

4 stages of quenching decreases temperature throughout.
Steam formation: metal I. The beaker metal starts to cool. forms a vapor field.
Steam coverage: covered in a cloud of vapor or steam blanket. Bubbles stick to the metal and consulate if from the quenching medium.
Steam discharge: a discharge where the film of bubbles collapses. Allows the metal to again make contact with the quenching medium. Agitation can decrease time in this stage. Very violent.
Slow cooling: cools at a slower cooling rate to a normal rate. No more vapor film.

Question 17

Process’s of Martempering

Answer 17

put in a molten salt booth just above it’s martensite start tempt. The quench is much less severe. Partial quench, hold, finish quench,reheat, hold, then quench. are done to minimize residual stress, distortion, and cracking.

Question 18

Proccess of Austempering

Answer 18

ss

Question 19

Product of Martempering

Answer 19

Tempered Martensite

Question 20

Thermal location Dislocation

Answer 20

Raise the temperature to rearrange the position of atoms in the crystal structure.

Question 21

Raise the temperature in tempering

Answer 21

will decrease yield strenght, and tensile strenght.

Question 22

Interupted Quenching

Answer 22

1. Metal is winched to martensite region. 2. Hold 3. Raised to Bainite. 4. Held at Bainite. 5. Then lowered to Martensite

Question 23

Full annealing is done to

Answer 23

Reduce Hardness and Brittleness, ie increase ductility. done at high temperatures and turns austenite to coarse pearlite.

Question 24

Normalizing is done to

Answer 24

increase hardness and strength. done at a faster cooling rate. forms fine pearlite

Question 25

Rapid heat treating is done

Answer 25

changes are caused by heat, not chemical changes. Only the preheated part is hardened.

Question 26

Carburizing

Answer 26

a process where iron absorbs carbon while it is heated in the presence of heat-treated metals. The main concern is quenching

Question 27

Flame hardening

Answer 27

used above the torch where heat is applied to only small selected areas. no carbon or nitrogen is added. Quenches rapidly. Most commonly used on medium carbon steel.

Question 28

Pack carburizing

Answer 28

put in a furnace with many carbon materials. gas Carbnoaceous: Carbon monoxide makes the carbon fuse into the material

Question 29

The main difference between Carburirzzing and Nitritiding.

Answer 29

Nitriding does not require secondary heat treatment like (quenching).

Question 30

Gas carburizing

Answer 30

Where the metal is subject to a carbonaceous gase such as carbon monoxide in an enclosed space. Then heated to a high temperature until carbon is diffused into material. A contnouoius gas is used. Longer it stays in that furnace the more parts will be produced

Question 31

Liquid Carburizing

Answer 31

Put into salt bath containing material liek cynanide and being heated by electricity. Solution is stirred transfer is done quickly

Question 32

What steels is flame hardening used for

Answer 32

Medium Carbon Steel is the most common. must contain enough carbon.

Question 33

Induction Hardening

Answer 33

Uses a copper coil and the process of induction to heat the metal and then quenched. Alternating current at high frequency. Electric resistant of part is used to heat metal. Most expensive but also most efficient.

Question 34

Nitriding

Answer 34

The steel is heated at below the Austnetic temperature where Ammonia is added to allow for the nitrogen atoms to enter the steel.

Question 35

Normalizing and annealing do what to affect the crystal structure of the grains

Answer 35

it will return it back to original shape

Question 36

How Slow cooling affects cracking

Answer 36

Slow cooling allows for less cracking and distortion of the surface of the material.

Question 37

Rapid heat treatment hardening of metal when quenched must have

Answer 37

a high enough carbon content.

Question 38

what composition change process produces the most hardness?

Answer 38

Nitriding

Question 39

Normalizing

Answer 39

Heating 20 degrees above upper transformation line.

Question 40

4 different Nitriding methods

Answer 40

Nitriding, Cyanididng, Carbonitriding, vacuum gas nitriding.

Question 41

Laser/ Electron Beam Hardening

Answer 41

concentrated and precise beam sent to heat the metal. Instantaneous process.

Question 42

Carbonitriding

Answer 42

Metalis is heated in chamber with ammonia and natural gas. induces surface with carbon and nitrogen atoms. Heat treated to temperature less than carburizing then Left to quench. Can increase wear resistance

Question 43

What quenching medium is heat for low carbon steels

Answer 43

Water

Question 44

Best Quenching medium for cast iron

Answer 44

Air

Question 45

Lowest temp medium

Answer 45

Brine

Question 46

Tempering happens after

Answer 46

Quenching and Annealing

Question 47

Full Annealing

Answer 47

Heated to 50-100 f above utt. Held their and completely changes to Austenite

Question 48

Sheropheredizing g is done on what steels

Answer 48

High carbon steels.

Question 49

Procces Annealing

Answer 49

Heated below LTT. Used when time/furnace time is a concern

Question 50

Die casting

Answer 50

Where molten metal is inserted into container under very high pressure for increased strnenght and more precise dimensions

Question 51

advantages of nitriding

Answer 51

more corrosion resistance, less cracking, requires less cleaning than carburizing.

Question 52

three issues with quenching.

Answer 52

cracking, distortion, and internal stresses.