1. Effect of Carbon (C) in steel

What is the Carbon (C) effect on steel material?

Carbon is the most important element found in steel material. Steel material mechanical strength is directly connected with carbon content.

When the carbon element content increased, yield point and tensile strength increased, but the plasticity and impact reduced.

In the case of carbon content more than 0.23%, steel welding performance will get worse.

So in the low alloy steel structural, to get better welding performances, the carbon content usually less than 0.2%.

Meanwhile, high carbon content also reduces the air corrosion resistance of steel, and the high carbon steel in the open field is easy to rush.

In addition, carbon will increase the cold brittleness and the aging sensitivity of steel.

2. Effect of Phosphorus (P) on steel

Effect of phosphorus on steel made various effects on steel pipe and steel plate, in the case of different concentrations.

Generally speaking, phosphorus is a harmful element in steel, it will increase the cold brittleness. It makes welding, pending performances get worse and reduce the plasticity.

Therefore, the content of phosphorus in steel material is usually less than 0.045%, in high-quality steel material grade, it is lower.

In higher steel grade, the P content is 0.03 to 0.05, if P exceeds 0.10 in low alloy high strength steels, it will increase the strength as well as improve the corrosive resistant performances. But the bad part is even the strength increased through P, it becomes brittle, ductility and toughness will reduce.

3.Effect of Sulfur (S) in steel pipe

Effect of Sulfur in steel.

As we know, sulfur is a harmful element. It increases hot brittleness, reduces the ductility and toughness, causes cracks in forging and rolling.

Secondly, Sulfur is bad for welding performance, reduce the corrosion resistance. So it usually requires the sulfur content is less than 0.055%.

For high-quality steel, it requires S should be less than 0.04%. Adding 0.08-0.2% sulfur could improve cutting performance, which often called easy cutting steel.

So even S is a harmful element, if content less than 0.05%, it would be accepted in general applications.