Mild steel Brief introduction
One of the classes in the low-carbon steel, low carbon content, the hardness smaller steel. (Reference: carbon content of 0.13% to 0.20
%) And the microstructure of ferrite plus a small amount of pearlite, characterized by low hardness (HB 100 to 130), low intensity (σb is 372 to 470 MPa), high plasticity (δ is 24% to 36%), shaping and weldability steel foundry
Mild steel Composition and structure
Steel is an iron-carbon alloy carbon content between 0.04% -2.3%. In order to ensure its toughness and ductility, the carbon content is generally not more than 1.7%. The steel main element in addition to iron, carbon, silicon, manganese, sulfur, phosphorus and the like.
The steel is added to the iron (Fe), carbon (C) is synthesized from, depending on the number of C content and harden or soften. Mild steel, hard steel of the difference is that the C content:
Very soft steel the C content of 0.15% or less —-
— Soft steel of the content of 0.20% to 0.30%
Content of 0.30% to 0.50% — semi-hard steel
Content of 0.50% to 0.80% — hard steel
— Extremely hard steel of the content of 0.81.2% to 3.0%
Indeed steel in addition to the carbon (C), further mixed with silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), these elements and carbon (C) of five elements of the steel, collectively referred to as examination of the chemical composition of the steel, the first five elements for analysis. Five elements on the effects of the physical properties of the steel are as follows:
Carbon (C): the important elements of the steel indispensable, can increase the hardness, strength;
Silicon (Si) can increase the strength and hardness;
Manganese (Mn) can increase the toughness of the steel, high toughness steel containing Mn 1.2% ~~ 1.5%;
Phosphorus (P) the steel harmful elements, steel cold brittle, content little as possible;
Sulfur (S) and P are harmful elements, steel hot shortness.
Mild steel Classification
Distinguish its physical properties:
Hard steel and soft steel yield point divided according to whether they exist, because of the hard steel no obvious yield point, plastic softer steel, so its control stress factor than .
1. Mechanical properties of soft steel
Mild steel (hot rolled steel) yield point, before the damage of the clear signs (large deformation, ie elongation), is a plastic failure.
2. The mechanical properties of hard steel
Hard steel (heat-treated steel bars and high-strength steel wire) high strength but poor ductility, brittleness. From load to suddenly pull off, basically there is no yield phase (stream width). The case of brittle failure.
The plasticity of the material directly affects to the destructive nature of the structural member. So, should choose a the plastic good reinforcement.
Steel wire and strand are hard steel, cold drawn hot rolled bars are . Hard steel and soft steel yield point divided according to whether they exist, because of the hard steel no obvious yield point, plastic softer steel, so its control stress factor than mild steel.
Product forms such as bar, plate, tube, strip, directly used in the rolling state can manufacture all kinds of construction machinery components, in particular the need for welding, riveting, cold working parts, such as the boiler casing, flame tube, aircraft suction pipe, fuel pipe, water pipe, Reinforcing.