Carbon Steels
What quantity of chromium do martensitic steels have?
13% chromium (and 0.3% carbon and 1.0% nickel)
What quantity of chromium do ferritic steels have?
14% chromium (and 0.04% carbon and 0.5% nickel)
What quantity of chromium do austenitic steels have?
18% chromium (and 0.1% carbon and 8.0% nickel) also known as 18/8
What are stainless steels?
Alloy steels that contain a high proportion of Chromium to provide corrosion resistance
What is the result of oxidisation?
Bronze is weakened and becomes hard, brittle and scratchy
What are ferrous metals?
Cast irons that contain 3% carbon. Low cost engineering material.
What are ferrous metals?
Plain carbon steels that have other metals added to them. These are called alloying elements.
What are the properties of high carbon steels?
They are harder, more expensive and less ductile than both mild and medium carbon steel
How many groups of high carbon steel are there?
Three: 0.8 to 1.0% carbon (used for chisels) 1.0 to 1.2% carbon (used for metal cutting tools) 1.2 to 1.4% carbon (working knives)
What is the percentage of sulphur and phosphorus?
Up to 0.05%
What is the most corrosion resistant of all the stainless steels?
austentitic
How much carbon is in low carbon steels?
between 0.1 and 0.15% carbon
How much carbon is in medium carbon steels?
between 0.3 and 0.5% carbon
What is the forging temperature of high carbon steel?
between 700 and 900 degrees Celsius
What elements are contained in carbon steels in addition to iron?
carbon, manganese, silicon, sulphur and phosphorus
What products can be made using medium carbon steel?
drop hammer die blocks, laminated springs, wire ropes, screw driver blades, spanners, hammers and heavy duty forgings
What are non ferrous metals and alloys?
metals and alloys that do not contain iron
Name some common alloying elements
nickel, chromium, Molybdenum, manganese, tungsten and cobalt
What are high carbon steels used for?
springs, cutting tools, dies
What are high speed steels?
they are a group of alloy steels containing metallic elements such as tungsten and cobalt. They are used for making tools suitable to cutting metals.
What are the properties of medium carbon steel?
they are harder, stronger and tougher than low carbon steel
What are the properties of low carbon steel?
they are soft and ductile
What are the disadvantages of using medium carbon steels?
they need close temperature control to avoid 'burning' which leads to embrittlement and 'cracking' which leads to hardening
What is the percentage of silicon?
up to 0.3%
what is the percentage of manganese?
up to 1%
