How to choose 35# and 45# steel?

45# steel is a high-quality carbon structural steel, its strength is 61, HRC is 48-55, and it is used more mechanically; 35# steel is also a high-quality carbon structural steel, but its strength is only 54, HRC is 38- 45. The difference between them can be distinguished from sparks. Sparks with low carbon content have a drooping tail and a slightly darker color. Sometimes there are spear-pointed tail flowers. The amount of flowers is not much and the thread is thick. For 45# steel, there is a bifurcation phenomenon in the streamline at the end of the straight end of the tail, which has a large shooting force and a large amount of flowers.
 
45# steel has a higher carbon content than 35# steel. Of course, 45# steel is relatively hard.
 
The difference between 35# steel and 20# steel
 
Both steel 20# and steel 30# steel are high-quality carbon steels. The numbers in their grades indicate the carbon content of the steel. Steel 20 indicates a carbon content of about 0.2%; 35 steel has a carbon content of about 0.35%.
 
The main difference: 20# steel belongs to low carbon steel, and its plasticity is good. It is mainly used to make profiles that can be stamped and formed, such as steel pipes and plates. 35# steel is medium carbon steel with high strength, which is mainly used to produce heat-treated Mechanical parts, such as gears, shafts, etc.
 

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