EN3B – BRIGHT BAR Grade Introduction:
The term Mild Steel applies to all low carbon steel that does not contain any alloying elements in its makeup and has a carbon content that does not exceed 0.25%. The term “Mild” is used to cover a wide range of specifications and forms for a variety of Steel.
Mild Steel is used in mechanical engineering applications for parts that will not be subject to high stress.
When in its bright cold drawn condition the Steel is able to endure higher levels of stress, particularly on smaller diameters.
Compared to normal Mild Steel, bright Mild Steel provides tighter sectional tolerances, increased straightness, and a much cleaner surface. The main advantage of cold drawn Steel is that Steel can be brought closer to the finished machine size, providing reduce machining costs. Another benefit of bright Steel bars is a marked increase in physical strength over hot rolled bars of the same section.
EN3B bright Mild Steel (070m20) used to be the most popular specification of bright Mild Steel available. It has since been replaced by steels that have a tighter chemical analysis.
EN3B Bright Mild Steel is now a general purpose Steel that is suitable for welding, can be case-hardened and is good for general machining. EN3B is generally used in engineering applications that will not be heavily stressed.
EN3B – BRIGHT BAR Grade Application:
  • Shafts & rollers
  • Machinery parts
  • Threaded bars
  • Spindles & axles
  • Low stress engineering applications
EN3B – BRIGHT BAR Equivalent grades: 
BS 970 1991
BS 970 1955 EN
AISI/SAE
Werkstoff
070M20
EN3B
1020
1.0402
   
Chemical composition: 
The following table shows the chemical composition of EN3B steel:
Element
C
Si
Mn
P
S
Cr
Mo
Ni
Content (%)
0.25 Max
0.35 Max
1.0 Max
0.06 Max
0.06 Max
EN3B – BRIGHT BAR Mechanical Properties: 
Condition
Tensile Strength
MPa Min.
Yield Strength
MPa Min.
Elongation %
Cold drawn
560
440
10
Turned & Polished
430
215
21