Question 1

What are the Primary and Secondary working operations?

Accepted Answer

Primary - Rolling, Extrusion, Forging, Machining Secondary - Wire drawing

Question 2

What is Rolling?

Accepted Answer

It is the process of reducing the thickness or cross section of a workpiece by compressive forces applied through a set of rolls. Production of flat plates or structural shapes, e.g. I-beams High speed production High capital investment required

Question 3

What's a Steckle mill?

Accepted Answer

Steckle mill used for producing medium sized sheet material, say 5mm thick. Coil on left hand side, uncoils, through set of rolls, coiled up on other side, process repeats itself until required thickness Can apply a tension to your piece of material as it is being deformed In theory, gives a better surface quality at the end

Question 4

What does Rolling Force increase with?

Accepted Answer

Flow stress, rolling reduction, roll radius, width. Increasing temperature decreases flow stress, therefore decreases rolling load

Question 5

What's Extrusion?

Accepted Answer

A round billet is placed into a chamber and forced through a die opening by a ram Normally carried out at elevated temperatures Pressure requirements will govern the choice of operating parameters

Question 6

What's the main defect of Extrusion?

Accepted Answer

Surface cracking can occur if the extrusion temperatures are either too high or too low, or if the extrusion speed is too high to allow the material to deform

Question 7

List some components that can be produced by Forging

Accepted Answer

Crankshafts, gears, wheels, turbine blades, and many other structural components

Question 8

What is Forgeability?

Accepted Answer

Forgeability is the capability of a metal to undergo deformation without severe surface cracking. Materials with good forgeability should be able to be shaped by low forces without cracking

Question 9

How can forgeability be quantified?

Accepted Answer

Simple simulation tests, such as upsetting tests or hot twist tests

Question 10

What is Isothermal Forging?

Accepted Answer

Dies are heated to the same temperature as the workpiece. Cooling of the specimen is eliminated, and the low flow stress of the metal is maintained.

Question 11

What is a particular problem in all three deformation processes?

Accepted Answer

Anisotropy

Question 12

What are the advantages of Isothermal Forging?

Accepted Answer

Forging can be carried out over a very narrow temperature range and at longer times. Much greater control over the microstructural and mechanical properties. Very good dimensional accuracy, but compared to other routes, is expensive

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Metals - Solid State Processes Flashcards

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