Metallic Materials Testing

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What does the Rockwell hardness tester measure?

Depth to which the penetrator sinks into the material (correct)

Diameter of the impression

Temperature of the material

Weight of the material

How is the depth of penetration represented by the Rockwell hardness tester?

In thousandths of an inch

In Brinell numbers

In Celsius scale

In Rockwell numbers on a red or black scale (correct)

What does the Brinell hardness tester measure?

Weight of the material

Temperature of the material

Depth to which the penetrator sinks into the material (correct)

Density of the material

What kind of load is initially applied by the Rockwell hardness tester?

Minor load Signup and view all the answers

How is tensile strength of ferrous metal tested?

By applying a longitudinal load and measuring the resulting deformation Signup and view all the answers

What does the Rockwell hardness tester indicate in its test results?

Depth of penetration in Rockwell numbers Signup and view all the answers

What is one of the properties tested for in metallic materials after a heat-treatment process?

Tensile strength Signup and view all the answers

Which hardness testing method uses a hydraulic force to impress a spherical penetrator into the surface of a metal sample?

Brinell method Signup and view all the answers

What is typically used to measure the hardness of metals?

Calibrated microscope Signup and view all the answers

Why is it necessary to test metallic materials after a heat-treatment process?

To ensure desired qualities have been achieved Signup and view all the answers

Which property is often correlated with the hardness of most metals?

Tensile strength Signup and view all the answers

How is the Brinell number calculated in the Brinell hardness testing method?

By converting the impression diameter measured with a calibrated microscope Signup and view all the answers

What is the purpose of fatigue strength testing?

To establish the stress level at which structural failure will occur Signup and view all the answers

How is fatigue life determined in fatigue strength testing?

By measuring the number of cycles completed Signup and view all the answers

What is a key purpose of airframe fatigue testing for aircraft?

To identify causes of premature fatigue damage Signup and view all the answers

How are aircraft components benefited from fatigue strength tests?

By determining their fatigue life Signup and view all the answers

In what way does tensile testing differ from fatigue strength testing?

Tensile testing focuses on static strength, while fatigue strength testing examines cyclic loading. Signup and view all the answers

Why is it important to conduct airframe fatigue tests on aircraft?

To predict potential structural failures and develop maintenance programs Signup and view all the answers

What is the main difference between the Izod and Charpy impact tests?

The beam configuration used Signup and view all the answers

Which impact testing method is most commonly used for metals today?

Charpy V-notch impact test Signup and view all the answers

What shape is the specimen in the Charpy V-notch impact test?

Bar of square cross section Signup and view all the answers

What type of hammer is used in impact resistance testing?

Pendulum hammer Signup and view all the answers

What happens to the pendulum in the Charpy V-notch impact test after striking the specimen at the notch?

Continues its swing Signup and view all the answers

In the Izod impact test, what type of beam configuration is used?

Cantilevered configuration Signup and view all the answers

Study Notes

Hardness Testing

The Brinell hardness tester measures the diameter of the impression made by a spherical penetrator on a metal surface, which is then converted to a Brinell number.
The Rockwell hardness tester measures the depth of penetration of a penetrator into a metal surface, indicated by a Rockwell number on a red or black scale.

Rockwell Hardness Tester

Uses minor and major loads, with three types of penetrators and three major loads available.
Provides the same information as the Brinell tester, but measures the depth of penetration instead of the diameter of the impression.

Tensile Strength Testing

Tests the tensile strength of a ferrous metal by applying a longitudinal load to a sample and plotting the load against the resulting elongations on a graph.
Provides data on the strength of a metal.

Testing of Metallic Materials

Testing is carried out with a test piece of the same material and thickness as the component being tested.
Properties tested for include hardness, tensile strength, fatigue strength, and impact resistance.

Impact Resistance Testing

The Charpy and Izod impact tests measure the impact resistance (or impact strength) of a metal.
Both tests involve a pendulum hammer fracturing a notched piece of material with one blow.
The main difference between the two tests is the beam configuration used.

Charpy V-Notch (CVN) Technique

A common impact testing method used for metals.
Involves a specimen with a V-notch, which is struck by a weighted pendulum hammer.
The pendulum continues its swing, rising to a maximum final height, which is lower than the initial height.

Fatigue Strength Testing

Establishes the stress level at which structural failure will occur.
Involves a specially shaped test piece subjected to tension and compression stresses in a rotating machine.
The number of cycles completed is measured to determine fatigue failure, which is then classified as fatigue life.

Airframe Fatigue Testing

Aircraft are subjected to fatigue tests to determine the likelihood and causes of premature fatigue damage or wear on the airplane's structure and structural components.
Provides data for the development of maintenance programs.

Studying That Suits You

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

Description

Learn about the testing of metallic materials after heat treatment to ensure desired qualities such as hardness, tensile strength, fatigue strength, and impact resistance. Find out how testing is done using a test piece matching the material and thickness of the component.