Rockwell Hardness Test Concepts

The video explains the Rockwell hardness test, focusing on scale C, using a gear wheel. It describes the test's basic idea, which involves measuring the permanent depth of indentation by a diamond cone indentor under specific forces. The process is divided into three steps: applying a minor force, increasing to a major force, and then removing the major force to measure the indentation depth. The Rockwell hardness (HRC) is calculated using a specific formula. The video also demonstrates the practical application of the test and highlights the automation of the process in modern testing machines, making it suitable for automated production lines.

What is the primary purpose of the Rockwell hardness test?

• To calculate the temperature resistance

• To measure the permanent depth of indentation

• To determine the weight of a material

• To measure the color of a material

What type of indentor is used in the Rockwell hardness test scale C?

• A steel ball

• A rounded cone made of diamond

• A flat plate

• A cylindrical rod

What is the minor force applied to the test piece in the first step?

• 20 kiloponds

• 50 kiloponds

• 10 kiloponds

• 30 kiloponds

How much is the test force increased by in the second step?

• 100 kiloponds

• 120 kiloponds

• 140 kiloponds

• 160 kiloponds

What is the total force acting on the indentor during the major force application?

• 100 kiloponds

• 150 kiloponds

• 200 kiloponds

• 250 kiloponds

How is the Rockwell hardness HRC calculated?

• 0.2 minus permanent depth of indentation e in millim times 100

• 0.2 minus permanent depth of indentation e in millim times 200

• 0.2 minus permanent depth of indentation e in millim times 300

• 0.2 minus permanent depth of indentation e in millim times 500

What is the first step in the practical demonstration of the Rockwell hardness test?

• Installing the conical diamond indentor

• Selecting the test piece

• Measuring the depth of indentation

• Applying the major force

What is adjusted to ensure the test piece is at the correct height?

• The support table

• The test force

• The microscope lens

• The indentor

What is a key feature of modern Rockwell hardness testing machines?

• They are fully automated

• They require constant supervision

• They are manually operated

• They use a steel ball indentor

What was the Rockwell hardness result of the gear wheel in the video?

• 50 HRC

• 45 HRC

• 55 HRC

• 60 HRC