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Product Design

Ferrous and Non-Ferrous Metals


Learning objectives


Le

arn

ing

ob

jecti

ves

To understand where metals come from and how

they are prepared for use.

To look at examples of ferrous metals, non-ferrous

metals and alloys, and to know the properties of

different metals.

To understand how heat treatment can change the

properties of metals.

To be able to use hand tools to work with metals.

To be familiar with the industrial processes used to

manufacture metal goods.


Metals are common in manufacturing today. From

building and construction work to vehicles and

leisure products, they are a vital material for product

designers and engineers.

The elements of all metals are found naturally

in the earth. However, they need to be extracted

and processed before they can be used for

manufacturing purposes.

Because metals in their most basic form are

natural resources, designers and

manufacturers need to be careful and

socially responsible about how much they use,

and reuse or recycle metals where possible.

Background on metals


Metals form part of the earth’s crust as metal ore. To obtain

useful metals, the metal ore is mined and washed to

remove other minerals and unwanted materials.

Iron ore is the basis for most steels. To extract pure iron the

iron ore is heated in a furnace in a process known as

smelting.

Where do metals come from?


Primary processes – rolling


Primary processes – extrusion


Metals are available in several raw forms. Each form is

suitable for different manufacturing processes depending on

the type of equipment used, the cost of the metal, the scale

of production and the properties of the finished product.

Stock forms of metals

octagonal

hexagonal

square

round rod

sheet

flat strip round tube

square tube

angle

channel


Metals can be broken down into these main categories:

Non-ferrous

metals

Ferrous

metals

Allo

ys

Allo

ys

Pu

re m

eta

ls

Pure metals do

not contain any

other metals or

elements.

Categories of metals


Ferrous metals are obtained from iron ore. You might

recognize the letters ‘Fe’ from the periodic table, where they

represent iron.

Iron replaced bronze as the

principal metal by 1000 BC.

Early pots and pans made from

iron poisoned the users!

Early steels were made by

adding carbon to iron as it was

melted over a charcoal fire.

Ferrous metals

Ferrous metals:

contain iron

will corrode unless

protected

are attracted by a

magnet

are strong, rigid

and cheap.

Ferrous facts


A closer look at ferrous metals


Non-ferrous metals do not contain iron. These are pure

metals used by designers, manufacturers and engineers in

a wide variety of applications.

Aluminium is the most common

non-ferrous metal, found in

abundance in bauxite ore.

Non-ferrous metals are not

magnetic.

Non-ferrous metals

Non-ferrous metals:

contain no iron

are not attracted

by a magnet.

Non-ferrous facts


A closer look at non-ferrous metals


Sometimes ferrous and non-ferrous metals require different

properties in order to function better in specific situations.

Alloying metals involves mixing two or more metals and

other elements to improve their properties.

Alloys

Alloying metals can:

lower the melting point

alter thermal and electrical properties

make a material harder for cutting purposes

improve resistance to corrosion

help metal to flow better into a cast.


A closer look at alloys


Random alloy generator


Metals and their properties


Changing the properties of metals


Heat treatment – hardening steel


Heat treatment – tempering


Heat treatment – annealing


Working with metals – hand tools


Milling machines are used to remove thin

layers from a billet (block of material)

which is clamped to the bed (base) of the

machine. The material is fed past a cutting

tool which has many sharp teeth and can

remove material quickly.

Industrial processes

When manufacturers want to make

cylindrical products, they use a centre

lathe. Metals and plastics can be used

on this machine. The work is held in a

chuck and a cutting tool is moved

towards the work while being held in a

tool holder, mounted on the tool post.


Several surface finishing techniques can be used on metals.

The most common ones are detailed below:

Paint

Plastic Coating

Lacquering

Enamelling

Surface must be smooth and

de-greased

Primer required

Hammerite is a good one-coat

metal paint.

Suitable for most metals

Object is heated and dipped in a

tank of powder paint

Object is returned to oven to

ensure a smooth, glossy finish.

Helps to prevent corrosion

after polishing

A layer of cellulose or varnish

is applied

Often used on jewellery.

Powdered glass is melted

onto the metal surface

Provides a hard (but brittle)

finish with different colours

and textures.

Finishing techniques


Key points


Ke

y p

oin

ts

Metals are extracted from the earth’s crust and then

prepared into standard shapes before being sold to

manufacturers.

Ferrous metals are obtained from iron ore and

include cast iron and steel. Non-ferrous metals

include aluminium, copper and tin.

Alloys, such as brass and stainless steel, are formed

from two or more metals and other elements.

Different elements alter the properties of metals.

Heating metals also alters their properties.

Metals can be worked with hand and machine tools,

including milling machines and centre lathes.

Documents

Ferrous and Non-ferrous Metals - libvolume6.xyzlibvolume6.xyz/mechanical/btech/semester3/material... · Non-ferrous metals do not contain iron. These are pure metals used by designers,