| Programmer | Code | Related chemical composition | Hardness（HB） | Extensio（%） | Tensile Strength（MP） | Yield Strength（MP） | ||||
| Material | C | Si | Mn | P | S | |||||
| Mn board | Q345B | 0.18 | 0.55 | 1.4 | 0.03 | 0.03 | 163-187 | 21 | 470-660 | 345 |
Q345B steel is a Chinese standardized low alloy, medium tensile strength steel made with a hot-rolling process, and is used for a number of manufacturing purposes. It is a steel with less than 0.2 percent of its composition made up of carbon, less than 0.55 percent of its composition made of silicon and several impurities (mostly sulfur, chromium and nickel). This particular grade of steel is a 'general purpose' manufacturing steel in construction equipment field, such as Q345B is basic mateiral of making excavator bucket and Excavator long reach booms
The major benefit of this grade of steel is its mild temper. It's easy to form and easy to weld,
Mechanical Properties
1, Yield Strength
A yield strength or yield point is the material property defined as the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed, Yield strength of Q345B is 345 MegaPascals. Like most steels of its grade, it suffers elongation before it pulls apart, typically at 20-21 percent of its initial length.
2, Tensile strength
The tensile strength of a material is the maximum amount of tensile stress that it can take before failure, for example breaking. Steel tensile strength is expressed in units of force divided by cross sectional area; in the Metric system, this unit is known as the Pascal. One Pascal is a Newton (the force needed to accelerate a one kilogram object to a velocity of one meter per second) per square meter. The tensile strength of Q345B steel is rated at 470 to 660 MegaPascals (where mega is million)
3, Hardness (HB)
Brinell scale hardness characterizes the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of hardness in materials science, The typical test uses a 10 millimetres (0.39 in) diameter steel ball as an indenter with a 3,000 kgf (29.42 kN; 6,614 lbf) force, copper hardness is 35HB, Pure Aluminium is 15HB,
