Ferrous Metals Revision

Questions and Answers

When drilling stainless steel, what is the recommended drill angle and cutting speed?

Drill ground to 150 °, moderate cutting speed.

Drill ground to 90 °, fast cutting speed.

Drill ground to 120 °, slow cutting speed. (correct)

Drill ground to 90 °, slow cutting speed.

What process is used to galvanise a material effectively?

Coated with a zinc-based paint at room temperature.

Sprayed with a nickel solution.

Dipped in a bath of molten zinc. (correct)

Packed in a drum containing zinc dust and heated.

At what temperature is steel typically tempered?

At the annealing temperature.

Above the annealing temperature.

Below the annealing temperature. (correct)

At room temperature.

What is the primary benefit of tempering steel?

Relief of internal stress after hardening. Signup and view all the answers

What effect does adding chromium to steel have?

Improves hardness of the steel. Signup and view all the answers

Which of the following statements about the annealing temperature and steel is correct?

Tempering is done at temperatures below the annealing temperature. Signup and view all the answers

Which of the following is NOT a result of tempering steel?

Increased brittleness. Signup and view all the answers

What characteristic is primarily associated with steel that has had chromium added?

Greater hardness and strength. Signup and view all the answers

What effect does adding chromium to plain carbon steel have?

Increases its resistance to corrosion. Signup and view all the answers

Which statement accurately describes the purpose of case hardening?

Produces a hard case over a tough core. Signup and view all the answers

The hardness of high-carbon steel at normal temperatures is attributed to what factor?

The balance of carbon content in the granules. Signup and view all the answers

What is the process of nitriding primarily classified as?

A type of case hardening. Signup and view all the answers

What is the characteristic carbon content of medium carbon steels?

0.3 - 0.5%. Signup and view all the answers

Which element is essential for the classification of a metal as ferrous?

Iron. Signup and view all the answers

Which statement about ferrous metals is true?

Iron is a primary component and most ferrous metals exhibit magnetic properties. Signup and view all the answers

What is the primary goal of the annealing process in steel?

To relieve internal stress caused by previous mechanical work. Signup and view all the answers

The hardness range for cobalt steel as tested by the Brinell test typically falls between what values?

600 to 700. Signup and view all the answers

What action should be taken if a material is found in the tertiary phase of creep?

The component should be replaced immediately. Signup and view all the answers

Which method is primarily used for marking out steels?

Copper sulphate. Signup and view all the answers

Phosphating of steels involves immersing the steel in a solution that contains:

Phosphoric acid and metal phosphates. Signup and view all the answers

Tempering involves which heating and cooling method?

Heating below the lower critical temperature and slow cooling. Signup and view all the answers

What is true about austenitic stainless steels?

They are classified as non-magnetic. Signup and view all the answers

What is the primary transformation of steel during cooling from above the LCT?

The transformation of austenite into pearlite. Signup and view all the answers

Which method is specifically used to demagnetize steel after a NDT examination?

Degaussing. Signup and view all the answers

What structural change contributes most to the increased hardness of steel?

Formation of cementite. Signup and view all the answers

What is the cooling process characteristic of normalizing steel?

Cooling in still air. Signup and view all the answers

The purpose of normalizing steel is primarily to:

Remove residual stress from manufacturing. Signup and view all the answers

Cast iron is characterized by which of the following properties?

Heavy and brittle. Signup and view all the answers

Case hardening can be effectively applied to which type of metals?

Any ferrous metal. Signup and view all the answers

What type of corrosion is stainless steel exhaust systems particularly susceptible to?

Intergranular corrosion. Signup and view all the answers

What is a common consequence of heating steel above its critical temperature and then cooling it rapidly?

Both B and C. Signup and view all the answers

When is steel typically tempered during the heat treatment process?

After hardening treatment. Signup and view all the answers

Under what condition is the fatigue life of a steel component considered infinite?

When operated below the fatigue limit. Signup and view all the answers

What is the primary purpose of annealing steels?

Make the metal malleable. Signup and view all the answers

Which process is most appropriate for case hardening low carbon steel?

Pack or gas carburizing. Signup and view all the answers

What term describes the stress that remains in a steel product after manufacturing and heat treatment?

Residual stress. Signup and view all the answers

What is the main goal of tempering hardened steel?

Lower brittleness while maintaining strength. Signup and view all the answers

Which metallic element is crucial for the cutting ability of high speed steel?

Tungsten. Signup and view all the answers

When a low carbon steel bolt is stretched beyond its elastic limit, what happens?

It deforms permanently. Signup and view all the answers

1% Nickel and 1% Carbon steel is typically used for what application?

Ball and roller bearings. Signup and view all the answers

Fatigue failure is defined by which characteristic?

Reduction in strength due to alternating loads. Signup and view all the answers

What is one of the effects of normalising steels?

Relieves internal stresses. Signup and view all the answers

Which property describes cast iron accurately?

Heavy and brittle. Signup and view all the answers

Austenitic steel is formed under what specific condition?

Heated above the upper critical point. Signup and view all the answers

Refining pig iron to produce steel mainly involves the removal of which element?

Carbon. Signup and view all the answers

During a Rockwell Hardness test, what specifically gets measured?

The depth of the indent. Signup and view all the answers

What does the '0' in 2024-T3 indicate about the alloy?

The alloy has not been modified. Signup and view all the answers

What is eliminated by using two-piece tube connectors in aircraft hydraulic systems?

The flaring operation prior to assembly. Signup and view all the answers

What method can potentially reduce flare thickness during the tightening process?

Wiping or ironing the flare Signup and view all the answers

What happens to material during a tensile strength test?

It is pulled until it breaks. Signup and view all the answers

Which characteristic does impact resistance primarily measure?

Material toughness Signup and view all the answers

During a Vickers or Brinell hardness test, how long is the specified contact time between the indentor and test piece?

15 seconds Signup and view all the answers

The striking energy of the striker in an Izod impact test is approximately what value?

163 J Signup and view all the answers

What does the Charpy test evaluate?

Impact energy Signup and view all the answers

In terms of static U.T.S., what is the typical range for the fatigue limit of steel?

20%-40% Signup and view all the answers

What phenomenon allows mild steel to bear additional load after reaching its yield point?

Strain hardening Signup and view all the answers

What is the primary use of a Rockwell tester?

Testing for hardness Signup and view all the answers

Which of the following is not a type of hardness testing machine?

Izod Signup and view all the answers

Study Notes

Drilling and Material Treatment

Stainless steel requires a drill ground to 120° with a slow cutting speed for effective drilling.
Galvanization involves dipping a material in a bath of molten zinc to protect it against corrosion.
Tempering steel is performed below the annealing temperature to relieve internal stress without compromising material integrity.

Steel and Alloy Characteristics

The addition of chromium to steel enhances hardness and increases resistance to corrosion.
Case hardening produces a hard surface layer on ferrous metals while retaining a tough core to improve wear resistance.
Medium carbon steels contain approximately 0.3 - 0.5% carbon for balanced strength and ductility.

Ferrous Metals and Heat Treatment

Ferrous metals predominantly contain iron; they are often magnetic except for some stainless steels.
Annealing is used to relieve internal stress and increase malleability in steel by heat treatment.
Nitriding serves as a case hardening method to improve surface hardness and wear resistance.

Steel Properties and Treatment Processes

Cobalt steel exhibits high hardness ranging from 600 to 700 on the Brinell hardness scale, making it suitable for cutting applications.
Fatigue failure results from alternating loads reducing material strength over time rather than exceeding ultimate tensile strength (UTS).
Normalizing steel involves heating above the upper critical temperature (UCT) and then allowing it to cool in air to relieve stresses.

Specific Applications and Properties of Alloys

Austenitic stainless steels are categorized as non-magnetic and are produced above the upper critical point.
1% Nickel, 1% Carbon steel is typically used for ball and roller bearings due to its favorable strength and wear characteristics.
Low carbon steel is commonly case hardened using pack or gas carburizing methods to enhance surface durability.

Damage Assessment and Material Testing

Residual magnetism from non-destructive testing (NDT) examinations is eliminated through a process called degaussing.
The Charpy test evaluates impact energy resistance, an essential measure of material toughness.
The Rockwell hardness test measures the depth of the indent made by a specific load to determine material hardness.

Connection Techniques and Material Properties

Two-piece tube connectors in aircraft hydraulic systems prevent flaring thickness reduction during assembly, enhancing reliability.
Steel is produced by refining pig iron through oxygen blow to reduce carbon content, resulting in stronger material properties.
Tempering hardened steel significantly reduces brittleness while maintaining overall strength, crucial for practical applications.### Fatigue Limit of Steel
The fatigue limit for steel ranges between 20%-40% of its static Ultimate Tensile Strength (U.T.S.).

Strain Hardening in Mild Steel

Mild steel can endure additional load past the yield point due to strain hardening, which increases its strength after deformation.

Rockwell Tester

A Rockwell tester is primarily used for hardness testing, measuring a material's resistance to deformation.

Impact Resistance Test

The impact resistance test employs a weighted pendulum that strikes a material until it fractures, assessing the material's toughness.

Hardness Testing Machines

Common hardness testing machines include Rockwell, Brinell, and Vickers, each utilized for different material hardness assessments.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on metalworking techniques, particularly the correct methods for drilling stainless steel and the process of galvanizing materials. This quiz covers key concepts that every metalworker should understand to ensure precision and quality in their work.