In the field of precision machining, carbon steel is widely used, such as rivets, bolts, chains, bolts, tools, molds, measuring tools, precision accessories, etc. Carbon steel precision processing manufacturers must clearly distinguish the types and applications of carbon steel, because different grades and materials have different characteristics, and only by matching the number can they achieve products that satisfy users. Let’s take a look at the grades and corresponding uses of carbon steel:

1. Grades and uses of carbon steel

1. Ordinary carbon steel:  Carbon steel is divided into 5 grades according to the yield strength of steel: Q195, Q215, Q235, Q255, Q275 . Each grade is divided into grades A, B, C, D due to different quality. Q195, Q215,  Q235 have good plasticity and can be rolled into steel plates, steel bars, steel pipes, etc.; Q255, &#8194 can be rolled into steel, steel plates, etc.;

2, high-quality carbon structural steel: steel grade is expressed by the average mass ten thousand fraction of carbon. Such as 20#, 45#, etc. 20# means containing C: 0.20% (20 parts per 10,000). Purpose: Mainly used to manufacture various machine parts;

3. Carbon tool steel: The steel grade is expressed in terms of the average mass per thousand of carbon, and is prefixed with T. Such as T9, T12, etc. T9 means C: 0.9% (9 parts per thousand). Uses: Mainly used to manufacture various knives, measuring tools, molds, etc.; 4. Cast steel: Cast steel grades are prefixed with ZG in front of the numbers, and the numbers represent the average mass fraction of steel (expressed in ten thousand points). Such as ZG25, which means containing C: 0.25%. Uses: Mainly used to manufacture parts with complex shapes and requiring certain strength, plasticity and toughness, such as gears, couplings, etc.

2. Classification of carbon steel

1. According to the quality of steel (mainly factors such as the content of impurity sulfur and phosphorus):

Ordinary carbon steel (S ≤0.055%, P ≤0.045%)

High quality carbon steel (S ≤0.040%, P ≤0.040%)

High quality carbon steel (S ≤0.030%, P ≤0.035%)

2, according to the percentage of carbon content:

Mild steel (C: ≤0.25%) is also called mild steel. Mild steel is easy to accept various processing such as forging, welding and cutting. It is often used to make chains, rivets, bolts, shafts, etc.

Medium carbon steel (C: 0.25%<C ≤ 0.6%) has a variety of products such as killed steel, semi-killed steel, and boiling steel. In addition to carbon, it can also contain a small amount of manganese (0.70% to 1.20%). According to product quality, it is divided into ordinary carbon structural steel and high-quality carbon structural steel. Good thermal processing and cutting performance, but poor welding performance. Strength and hardness are higher than low-carbon steel, while plasticity and toughness are lower than low-carbon steel. Hot-rolled and cold-drawn materials can be used directly without heat treatment, or they can be used after heat treatment. The quenched and tempered medium carbon steel has good comprehensive mechanical properties. The highest hardness that can be achieved is about HB538, and the tensile strength σb is 600-1100MPa. Therefore, medium-carbon steel is the most widely used in various applications of medium strength level. In addition to being used as a building material, it is also widely used in the manufacture of various mechanical parts.

High carbon steel (C:>0.6%) is often called tool steel, with a carbon content from greater than 0.60% to 1.70%, which can be hardened and tempered. Hammers, crowbars, etc. are made of steel with a carbon content of 0.75%;  cutting tools such as drills, taps, reamers, etc. are made of steel with a carbon content of 0.90%  to 1.00% .

The higher the carbon content, the greater the hardness and strength, but the lower the plasticity (in addition, iron-carbon alloys with a carbon content of 2.1% to 4.5% are generally called cast iron.)

3, divided by purpose:

Carbon structural steel: Mainly used for bridges, ships, building components, machine parts, etc.;

Carbon tool steel: Mainly used for tools, molds, measuring tools, etc.

Whether it is for product research and development or product processing, different grades of steel should choose the corresponding processing technology. Only by matching the number can users be assured. Bomei Precision Technology Co., Ltd. strictly performs high-precision processing of carbon steel in accordance with user needs. The products cover many It has multiple types of high-precision CNC processing equipment (mainly including 100 sets of CNC lathes, milling machines, machining centers, CNC walking machines, cutting machines, turning and milling composite machining centers, etc.) in various industries and fields. Services and complete solutions serve users.