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85 Cards in this Set

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What is hardness?

The ability to resist wear, abrasion, cutting and indentation

What is the Brinell Tester?

A ball in a hydraulic press is pressed into the specimen and the dent diameter is measured

Wha is the Rockwell Tester?

A 1.6mm ball or cone is pressed with 100kg. The impression is converted to hardness reading

What is brittleness?

No deformation before breaking, breaks instantly

What is ductility?

Can be permanently deformed without breaking

What is plasticity?

Very soft and a tiny amount of elasticity. Plasticity is the opposite of brittleness

What is elasticity?

Ability to return to its original shape after force is removed

What is malleability?

Can be hammered or rolled into other shapes. Malleability is increased when heated

What is toughness?

Materials that do not break easily under sudden impacts

What is the Izod test?

One end is held in a vice and it is struck on the side. the energy required to break is the test.

What is the Charpy test?

The same as the Izod, however both side are supported and it is struck in the middle.

What is pig iron?

The first stage of iron produced from iron ore

How is pig iron made?

Iron ore is heated with coke and limestone, the slag on top is removed, and the remaining molten is pig iron

What is pig iron used for?

It is refined to make steel or cast iron.

How is cast iron made?

It is melted pig iron mixed with scrap iron.

What is the carbon content of cast iron?

2 - 4%

What is white cast iron and what is it used for?

White cast iron is very hard and brittle. It is mainly used for thing that will be subjected to excessive wear

What is grey cast iron and what is it used for?

It is a more softer iron than white cast iron, and has a good compressive strength. It is mainly used for machine bases and supports

What is malleable cast iron?

It is white cast iron that has been annealed to make it more tough and durable

What is annealing?

The process of heating and cooling a metal at a controlled rate.

If the carbon content in iron is less than 2%, what is it?

Steel

If the carbon content in iron is more than 2%, what is it?

Cast iron

What are the 2 groups of steels?

1. Plain carbon steel


2. Alloy Steel

How are carbon steels grouped?

Low - 0.005% - 0.3% carbon


Med - 0.3% - 0.45% carbon


High - 0.45% - 0.75% carbon


Very high - 0.75% - 1.5% carbon

What are the 8 alloys added to steel?

1. Nickel


2. Chromium


3. Molybdenum


4. Vanadium


5. Copper


6. Lead


7. Manganese


8. Tungsten







What are the advantages of adding nickel to steel?

- Excellent resistance to corrosion


- Improves toughness


- Good for bearings

What are the advantages of adding Chromium to steel?

- Resistance to oxidization


- Retains high strength at high temp


- Increases hardness


- 12% chromium or higher is stainless steel

What are the advantages of adding molybdenum to steel?

- Increases hardness and endurance


- Decreases 'creep'


- increases corrosion resistance

What are the advantages of adding Vanadium to steel?

Promotes hardening ability, and increases ductility

What are the advantages of adding Copper to steel?

Improves atmospheric corrosion resistance

What are the advantages of adding Lead to steel?

Improves machinability

What are the advantages of adding Manganese to steel?

Increases strength, hardness and resistance to wear

What are the advantages of adding Tungsten to steel?

Retains hardness and strength at high temperatures

Why is copper a desired engineering material?

- High electrical conductivity


- High heat conductivity


- High corrosion resistance


- Tough


- Ductile

What is brass

Brass is a mixture of copper & up to 40% zinc

What is brass mainly used for?

Valves, fittings and bearing shells

What is bronze and what are some of the uses?

Alloy of copper and tin, also used for valves, fittings and bearing shells

Why is aluminium desired for engineering?

- Malleable and ductile


- Good conductor


- Good heat conductor


- Highly resistant to corrosion

What are some of the alloys added to aluminium?

- Copper


- Zinc


- Silicon


- Manganese


- Nickel


- Magnesium


- Chromium

What is white metal and what is it chiefly used for?

White metal is tin and lead, it is mainly used for bearing materials

What is arc welding?

The act of joining 2 pieces of metal together by means of an electrical arc

What are the temperatures produced by an arc?

3000 - 8300 Degrees c

What is the purpose of electrode covering?

To protect the bead of weld from the atmosphere

What determines the rate of electrode consumption?

The current setting

What are the two types off current used in arc welding?

AC and DC

What are the 3 power sources used for arc welding?

1. AC - Transformer


2. DC - Generator


3. DC - From AC rectifier



Wha does the "E" mean on welding rods?

Means its suitable for electric welding

What does the first 2 digits mean on a welding rod?

Tensile strength eg. (60 means 60k lbs)

What does the third digit mean on a welding rod

Weld position

What dies the fourth digit mean on a welding rod?

Rod characteristics

What are the numbers that correspond to welding positions?

1. All positions


2. Flat or horizontal (vertical surface)


3. Only in flat position


4. Down hand only (vertical surface)

What type of electrical current is preferred for welding?

DC

What is straight polarity?

The electron flow is negative

What is reverse polarity?

Electron flow is positive

Briefly describe submerged arc welding

Welding beneath a granular surface



Briefly describe braze welding

High temperature solder not actually a weld that requires an oxy-acetylene setup

What are the four non-destructive weld tests?

1. Visual


2. Liquid dye


3. Radiographic


4. Ultrasonic

Briefly describe a liquid dye penetrant inspection, and what are the 2 types of dye used?

The 2 types are fluorescent and dye. The are simply put on the weld and cleaned off, and remaining will show defects

Briefly describe a radiographic inspection

X-ray on one side and special paper on the other side, if theres holes in the wells it will trap some of the x-rays showing it on screen

Briefly describe ultrasonic inspection

Same as radiographic but it is sound mesured

What is arc welding?

The fusion of metal by the process of an arc.

What does the axis of weld mean?

An imaginary line through the weld used as a reference point.

What does backfire mean?

The retreat of a flame into a torch tip

What does backing pass mean?

Going back over a weld again



What does backing strip mean?

Things put behind welds to increase thermal capacity

What is a backing weld?

A backing weld is a weld on the other side of a but joint weld to fill in any missing voids

What is a bare electrode?

An electrode with no coating

What is a base metal?

The metal to be welded or cut.

What is the bevel angle?

The angle perpendicular to the surface of metal



What is boxing?

The act of continuing a weld around a corner

What is carbon arc cutting?

The act of cutting metal with the heat of an arc between a carbon electrode

What is coalescence?

The fusion of 2 metals into one

What is a crater?

The depression or hole at the end of a weld.

What is the lead angle?

The act of pulling an electrode

What is porosity?

The amount of pockets or voids in a weld.

What is post heating?

The act of heating a weld after to slow the cooling process to prevent cracking

What is slugging?

Filling weld areas with foreign material for filler

What is undercut?

To deep of a weld in the corner weld

What is forge welding?

Heating metals and hammering them together

What is oxy acetylene welding?

Using an oxy torch to heat filler rod in a weld segment

What is the base metal?

Base metal is the same as the welding rod

T/F - Oxy acetylene welding is limited to thin materials?

True

What are the bottle pressures for oxy acetalyne welding?

Oxygen bottle - 15,400 kPa


Acetylene bottle - 1,720 kPa

What is Acetylene absorbed in and why?

Acetylene is absorbed in acetone because it is unstable by itself

Does oxy cutting burn metal and what temp

Yes burn 870 degrees c