Steel and it's Application

A page around the subject of steel and it’s application allows me to bring information together and help to build on a knowledge base.

Steel is an iron-based alloy containing carbon, and other alloying elements eg manganese. Steel contains anywhere between 0.2% carbon for soft wire and sheet steel and 1.5% carbon for cutting tools.

The American Iron and Steel Institute divides tool steels into six major categories:

  1. water hardening
  2. shock resisting
  3. cold work
  4. hot work
  5. special purpose
  6. high speed.

A work in progress as I add descriptions and data about the various types of steel.


Hot deformation of metastable austenite within controlled ranges of temperature and time that avoids formation of non-martensitic transformation products.


Quenching a ferrous alloy from a temperature above the transformation range, in a medium having a rate of heat abstraction high enough to prevent the formation of high-temperature transformation products, and then holding the alloy, until transformation is complete. The advantages of this method of interrupted quenching are increased ductility and toughness.

  • Austempering at lower temperatures (240°C to 270°C) produces a part with maximum strength.
  • Austempering at higher temperatures (360°C to 380°C) yields high ductility and toughness.


Non-magnetic face-centered cubic iron. Also iron and steel alloys that have the face-centered cubic crystal structure.

It is produced by heating steel above the upper critical temperature and has a high solid solubility for carbon and alloying elements. This temperature or temperature range is called the austenitizing temperature and must be attained to obtain the proper microstructure and full hardness of steel in heat treating. The austenitizing temperature varies for the different grades of carbon, alloy and tool steels.

Austenite can dissolve up to 2 percent carbon. Austenite is relatively soft, ductile and nonmagnetic.


An austenitic transformation product found in some steels and cast irons; it forms at temperatures between those at which pearlite and martensite transformations occur; the microstructure consists of alpha-ferrite and a fine dispersion of cementite.

This term is used by metallurgists to describe a particular structure of steel when the steel is polished, etched and examined with a microscope.

Cold Rolled Steel

Steel that has been rolled to accurate size and smooth finish when made. In contrast, hot-rolled steel may have a rough, pitted surface and slag inclusion.


Low carbon free cutting mild steel. Good machining qualities. Also known as: 230M07, AISI 1213


EN8 steel round rods

A medium tensile strength steel with a carbon content of 0.4 to 0.45%. The mechanical properties are just above those of mild steel. Can be heat treated to improve surface hardness. Also known as 080A40


An unalloyed medium carbon steel. Uses: Bolts, m/c Tool. Axial shaft. Also known as070m55


Manganese molybdenum steel with good ductile and mechanical strength and the ability to withstand shock loading. Uses include: High tensile shafts, bolts and gears. Also known as: 605M36T


A nickel chrome molybdenum steel with good ductile and tensile strength with good shock and wear resistance properties. Also known as: 817M40T


A nickel chrome case hardening steel that can be hardened to provide a very hard surface with a strong, tough core. Also known as655M13


A 0.70/0.85% carbon steel which is normally heat treated to achieve high hardness and for the production of springs. Uses: Gear case hardening tensils Tools.


Wear-resistance makes it ideal for edge tools and scraper blades. Uses: Spring action parts. Also known asAISI 1095


A manganese spring steel. Un-tempered EN45 is harder than mild steel, and will not suffer as much from burs or require as much repair. Uses: Leaf and conical springs.


High ratio of yield point to tensile strength and torsional fatigue strength.

Uses: High duty volute and leaf springs, Heavy engine valve springs,Helical and torsional bar springs.

Free Machining Steels

A group of steels designated as being easy to machine. Contain one or more additives, which enhance machining characteristics and lower machining cost.

High Speed Steel

high speed steels

Used a lot for cutting tools.

The image to the right shows some blank pieces ready to be ground to shape and then used as lathe cutting tools.

Maraging Steel

Steels which are known for possessing superior strength and toughness without losing malleability, although they cannot hold a good cutting edge.


Quenching an austenitized ferrous alloy in a medium at a temperature in the upper part of the martensite range, or slightly above that range, and holding it in the medium until the temperature throughout the alloy is substantially uniform. The alloy is then allowed to cool in air through the martensite range.


A metastable iron phase supersaturated in carbon that is the product of a diffusionless transformation from austenite.

Martensite is a microconstituent or structure in quenched steel characterized by an acicular or needle-lie pattern on the surface of polish. It has the maximum hardness of any of the structures resulting from the decomposition products of austenite.

Mild Steel

Used to cover a wide range of specifications and forms for a variety of Steels – in general it is used to describe steels that can be used in not very demanding applications.

single throw crankshaft

A single throw crankshaft machined from mild steel.

case hardening compound

Hardening: Mild steel can be case hardened to increase the surface hardness. Case hardening can be difficult to get hold of, but EKP Supplies Beta 1 compound.

Oil Hardening Steel: Heat the steel to 770 to 800°C and soak at this temperature for 3/4 hour per inch (25.4mm) thickness of material. Quench in a bath of oil inserting the heaviest end of the piece first (this way relieves stresses and reduces distortion). Further heat treatment at 100 to 120°C for a short while and then allowing the piece to cool naturally in air will reduce the stresses further and the possibility of cracking.

Note: the higher the carbon content the lower the hardening temperature of steel.

SAE Steel

Steel manufactured under the specifications by the Society of Automotive Engineers.

Silver Steel

There are a lot of uses for silver steel and a lot of these are because it is easy to harden. Also, silver steel is readily available in both metric and imperial round bar that is very accurate and so great for axles. Cutting speeds for silver steel, these are just an indication but they are a good starting point.

heat treating silver steel

Heat Treating Silver Steel is a great way of increasing it’s hardness after machining.

The heating, quenching and then tempering process is quite simple and worth learning for the hobby engineer.

Stainless Steel

A range of stainless steels are available that have varying degrees of resistance to corrosion, containing between 8 and 25% Chromium. Other elements used in Stainless Steel are Nickel and Niobium.

Machining: Keep the surface speed down to prevent work hardening. Work hardening can sneak up fast when machining stainless and so the default method is to go slow with a generous feed. Work hardening can also occur if the tool rubs on the surface.

The goal with the slow surface speeds is to reduce the work hardening. The goal of the higher feed rates is to make sure you are cutting a good distance under the surface that was previously cut to hopefully avoid having the cutter engage the hard surface.

Steel and it’s application is a page to come back to and extend the knowledge base, as such I would really like your additions to this and accompanying pages.

Tool Steel

Any steel used to make tools for cutting, forming, or otherwise shaping a material into a final part.

Water Hardening

High carbon grades of tool steel, straight carbon steels and low alloy steels that are hardened by quenching in water during the heat treating operation.

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