EN8M – BRIGHT BAR Grade Introduction:

EN8M Bright Bars is an important type of free cutting steel that has made its way into the market. These are widely used by several industries for the use in the production of the above mentioned instruments and parts. As this type of steel forms chips when it is worked on, they can take up only an average amount of heavy duty items at a time. When they are sold in the market, the grade of the free cutting varies with its composition. Sulphur or phosphorous are the two main types of ingredients that are added to the steel, apart from some little amounts of carbon.

EN8M type of free-cutting steel in Bright Bars has Sulphur added to it with a medium amount of carbon. They are mostly round or hexagonal in shape. These bars are used for making shafts, gears, studs, pins and gears.

Bright Bars have found usage at a very wide scale, extending quality construction finish, anti-corrosive properties, and high durability.

EN8M – BRIGHT BAR Grade Application:

These bars are used for making shafts, gears, studs, pins and gears.

Equivalent grades:

USA	Japanese	Germany	British	France	International	Chinese
ASTM&AISI&SAE	JIS	EN DIN	EN BS	EN NF	ISO	GB
1345	SMnC443	EN8M	EN8M	EN8M	——	45Mn2

EN8M – BRIGHT BAR Chemical composition:

The following table shows the chemical composition of EN8M steel:

Element	C	Si	Mn	P	S
Content (%)	0.35 – 0.45	0.25	1.00 – 1.30	0.060 Max	0.12-0.20

EN8M – BRIGHT BAR Mechanical Properties: 

Properties	Metric	Imperial
Hardness, Brinell (typical)	300	33
Hardness, Rockwell C (typical)	30	30
Tensile strength, ultimate	965-1030 MPa	140000-150000 psi
Tensile strength, yield	827-862 MPa	120000-125000 psi
Elongation at break (in 50 mm (2″))	20.0%	20.0%
Compressive strength	862 MPa	125000 psi
Charpy impact (V-Notch)	27.1-33.9 J	20.0-25.0 ft-lb
Poisson’s ratio	0.27-0.30	0.27-0.30
Elastic modulus	190-210 GPa	27557-30457 ksi

EN8M – BRIGHT BAR Hardness:

300

EN8M – BRIGHT BAR Heat treatment:

Heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each EN8M steel component. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities.

EN8M – BRIGHT BAR Hardening:

Heat the component slowly to 820-860°C and allow it to be heated through. Quench in oil or water.

EN8M – BRIGHT BAR Tempering:

Temper the EN8M component immediately after quenching whilst tools are still hand warm. Re-heat the EN8M component to the tempering temperature then soak for one hour per 25 millimeter of total thickness (2 hours minimum) Cool in air. For most applications tempering of EN8M will be between 550-660°C.

EN8M – BRIGHT BAR Forging Properties: 

Preheat the steel carefully, then raise temperature to 1050°C for forging. Do not forge below 850°C. After forging cool slowly, preferably in a furnace.

EN8M – BRIGHT BAR Annealing: 

Heat slowly to 680-710°C, soak well. Cool slowly in the furnace.