Welding of carbon steel

 

2.1 an overview of the

 

Carbon steel, also known as carbon steel, is iron and carbon alloy.Carbon steel, divided by carbon as the main alloy element, has a small amount of manganese and silicon beneficial elements.In addition, sulfur, phosphorus and other impurities.The properties of carbon steel depend on the carbon content.

 

Carbon steel is the most productive and widely used material in steel. Most welded structures are made of carbon steel.

 

 

 

2.1.1 classification of carbon steel

 

Carbon steels are classified in different ways and thus have various names:

 

(1) carbon content

 

It can be roughly divided into three types of low carbon steel, medium carbon steel and high carbon steel listed in table 7-2-1.Their carbon content range is not strictly limited, some countries between low carbon steel and medium carbon zha [w(C) about 0.15% ~ 0.3%] more soft steel, its typical hardness of 90HRB, its welding performance is good.

 

(2) by quality

 

The content of sulfur, phosphorus and other harmful impurities are classified

 

1) ordinary carbon steel contains w(S)≤ 0.050%, w(P)≤ 0.045%

 

2) high quality carbon steel with w(S)≤ 0.035%, w(P)≤ 0.035%

 

3) high-grade carbon steel with w(S)≤ 0.030%, w(P)≤ 0.035%

 

(3) according to the degree of deoxidation

 

1) the steel obtained from incomplete deoxidation of rimming steel has high oxygen content, more sulfur and phosphorus impurities, and uneven distribution, and there is a tendency of thermal crack and porosity when welding.

 

2) killed steel thoroughly deoxidized, so low oxygen content, less impurities.

 

3) semi-killed steel is between rimmed steel and killed steel.

 

(4) by purpose

 

1) structural steel is used to make various metal components and machine parts.

 

Tool steel is used to make various tools, such as measuring tools, cutting tools, molds, etc.