The steel structure manufacturer Wiskind will explain the factors that cause the difference in steel structure materials for you

chemical composition

Carbon: The main component of the strength of steel. As the carbon content increases, the strength of the steel increases, but at the same time the plasticity, resistance, cold bending function, weldability and rust resistance of the steel decreases, especially the impact resistance at low temperatures.

Manganese and silicon: the beneficial elements in steel are all deoxidizers, which can increase strength without excessively reducing plasticity and impact resistance.

Vanadium, niobium, and titanium: alloying elements in steel, which can not only improve the strength of steel, but also maintain outstanding plasticity and resistance.

Aluminum: A strong deoxidizer that uses aluminum to compensate for deoxidation, which can further reduce harmful oxides in steel.

Chromium and nickel: alloying elements of steel strength in steel building.

Sulfur and Phosphorus: Impurities and harmful elements left in the steel during exercise. They reduce the plasticity, durability, weldability and fatigue strength of steel. Sulfur can make steel "hot and brittle", and phosphorus can make steel "cold and brittle".

"Hot brittleness": Sulfur can produce iron sulfide that is easy to melt. When the temperature reaches 800-1000℃ by hot working and welding, the steel will appear to crack and become brittle.

"Cold brittleness": At low temperatures, phosphorus significantly reduces the impact resistance of steel.

Oxygen and nitrogen: harmful impurities in steel. Oxygen can make steel hot and brittle, and nitrogen can make steel cold and brittle.

The impact of metallurgical shortcomings

Common metallurgical shortcomings include segregation, non-metallic inclusion, pores, cracks, delamination, etc., which will make the steel function worse.

Hardened steel

Cold working such as cold drawing, cold bending, punching, and mechanical shearing causes the steel to undergo great plastic deformation, which then increases the yield point of the steel, and reduces the plasticity and resistance of the steel. This appearance is called cold work hardening or strain hardening .

Temperature effect

Steel is suitably sensitive to temperature, and both temperature rise and fall will change the function of steel. In contrast, the low temperature function of steel is more important.

At the positive temperature scale, the general trend is that as the temperature increases, the strength of the steel decreases and the deformation increases. The function of steel does not change much within about 200℃, and the strength (yield strength and tensile strength) drops sharply between 430℃ and 540℃; when it reaches 600℃, the strength is very low and cannot bear the load.

In addition, there is a blue and brittle appearance near 250 ℃, and a creep appearance at about 260-320 ℃.