Carbon Steel for Machine Structural use

Mechanical structural carbon steel is a type of steel material with carbon as the main alloying element, with carbon content usually ranging from 0.02% to 2.11%.

According to different carbon content, carbon steel can be divided into three types: low carbon steel, medium carbon steel, and high carbon steel. Low carbon steel and medium carbon steel are mainly used for mechanical structural purposes.

㈠ Basic Concept of Carbon Steel

　　Carbon steel is an alloy composed primarily of iron and carbon,
　　with carbon content typically ranging from 0.02% to 2.11%.
　　Depending on the carbon content, carbon steel can be divided into:

   ⑴ Low Carbon Steel (carbon content less than 0.25%):
　　Also known as mild steel, it has good ductility and toughness, and is easy to process.

   ⑵ Medium Carbon Steel (carbon content between 0.25% and 0.6%):
　　It has higher strength and hardness,
　　but lower toughness and ductility compared to low carbon steel.

   ⑶ High Carbon Steel (carbon content greater than 0.6%):
　　It has the highest hardness and strength, but lower toughness and ductility,
　　often used in the manufacture of tools and mechanical parts requiring high strength and wear resistance.

 

㈡ Characteristics of Carbon Steel for Mechanical Structures

   ⑴ Strength and Toughness:
　　The strength and toughness of carbon steel mainly depend on its carbon content.
　　Low carbon steel has high toughness but low strength,
　　while medium carbon steel achieves a balance between strength and toughness.

   ⑵ Machinability:
　　Carbon steel has good machinability during both hot and cold processing, suitable for welding, cutting, forging,
       and casting. Low carbon steel is especially easy to machine.

   ⑶ Wear Resistance:
　　Medium to high carbon steel has good wear resistance,
　　suitable for manufacturing parts that need to withstand friction and wear.

   ⑷ Economy:
　　Carbon steel is relatively inexpensive compared to other alloy steels,
　　and raw materials are readily available, offering good economic benefits.

 

㈢ Applications of Carbon Steel for Mechanical Structures

   ⑴ Mechanical Parts:
　　Such as gears, shafts, bolts, and connecting rods, requiring good strength and toughness.

   ⑵ Structural Components:
　　Such as building steel structures, bridge components, pressure vessels, requiring high load capacity and durability.

   ⑶ Automotive Industry: Including chassis, body structures, engine parts, requiring good strength and wear resistance.

 

㈣ Heat Treatment of Carbon Steel

   To improve the performance of carbon steel, heat treatment is usually performed, including:

   ⑴ Annealing: Softens the steel, improves toughness and machinability.

   ⑵ Normalizing: Improves the mechanical properties of the steel, eliminates internal stress.

   ⑶ Quenching: Increases hardness and strength.

   ⑷ Tempering: Adjusts hardness and toughness, reduces brittleness after quenching.

Product Applications

General connection rods, connectors, shafts, crankshafts, screws, automotive parts, machine parts, mechanical parts, such as mechanical tools.

S15C Low Carbon Steel

Low-carbon steel, is referred to steel contains <0.25%C, so

MORE
S15C Low Carbon Steel

Low-carbon steel, is referred to steel contains <0.25%C, so it has lower strength and hardness; therefore, it is called “soft steel.” By and large, it can be divided into “normal carbon structural” and “high-quality” steel; they can all be used as engineering parts without heat-treatment, or some of them are carburized to increase its wear-resistance and become mechanical parts. Because of lower strength and hardness and better plasticity and toughness, low-carbon steel can be performed cold-forming easily : side rolling, folding, punching,…etc. Besides, for steel that contains carbon from 0.10~0.30%, other good features can be found such as: good weldability, easy to forge and machine. Chains, rivets, bolts and shaft are commonly made of it.

Close
S45C Medium Carbon Steel

Medium-carbon steel, is referred to steel contains 0.25%~0.6

MORE
S45C Medium Carbon Steel

Medium-carbon steel, is referred to steel contains 0.25%~0.6C, so it has good machinability and higher strength and hardness than low-carbon steel but it is worse in weldability. Besides, medium-carbon steel can be directly processed by hot-rolling and cold drawing with or without heat-treatment, due to its lower plasticity and toughness. After quenching and annealing, medium-carbon can reach hardness of HRC55 (HB538) and obtain better general mechanical attributes. Therefore, medium-carbon steel has been applied the most; not only to architectural materials but great variety of mechanical parts.

Application: This steel is the most widely used steel in various industries. It is suitable for general connecting rods, joints, shafts, crankshafts, screws, auto parts, machine parts, machine parts, machine tools, etc.

Heat treatment method:
1. Hardening : uniformly heat to 820~870℃ and harden in water.
2. Tempering: Heat to 550~650℃ and quickly cool down.
3. Hardness: The hardness after treatment is HB 201~269.
4. Tension: 70KG/mm2 or more.
※When the carbon content is reduced by 0.05%, the heat should be increased by 10℃ (ie S40C 830~880℃).

Close
S20C

S20C is a common type of medium carbon steel MORE

S20C

S20C is a common type of medium carbon steel known for its excellent mechanical properties and machinability,widely used in the manufacturing of various mechanical structures and components.


㈠ Characteristics:
⒈ Applicability:　
　S20C steel is suitable for general mechanical structures such as bearings, gears, etc.
⒉ Machinability:
　It has excellent machinability, making it easy to be processed through cutting, forging, welding, and other machining processes.
⒊ Heat Treatment:
　It can undergo heat treatment to adjust its properties, such as annealing, quenching, and tempering.


㈡ Applications:
S20C steel is commonly used in the manufacturing of various mechanical parts and structural components,including bearings, bolts, gears, connecting rods, etc. Its moderate carbon content and suitable mechanical properties make it an ideal choice for many mechanical engineering applications.

Close

Steel data

Standard Code Spec No. Material No. Mark
AISI 1006
AISI 1008
AISI 1010
CNS 3828 S15C
JIS G4051 S15C
AISI 1015
SAE G10150 1015
DIN 17210 1.0401 C15
GB 699 15
SAE G10180 1018
CNS 3828 S20C
JIS G4051 S20C
AISI 1020
DIN 17200 1.0402 C20
DIN 17200 1.1151 Ck20
CNS 3828 S35C
JIS G4051 S35C
AISI 1035
DIN 17200 1.0501 C35
DIN 17200 1.1181 Ck35
CNS 3828 S45C
GB 699 45
JIS G4051 S45C
AISI 1045
DIN 17200 1.0503 C45
CNS 3828 S55C
JIS G4051 S55C
AISI 1055
(C)% (Si)% (Mn)% (P)% (S)% (Ni)% (Cr)% (Cu)% Ni+Cr
≦ 0.08 0.25~0.4 ≦ 0.04 ≦ 0.05
≦ 0.1 0.3~0.5 ≦ 0.04 ≦ 0.05
0.08~0.13 0.3~0.6 ≦ 0.04 ≦ 0.05
0.13~0.18 0.15~0.35 0.3~0.6 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3
0.13~0.18 0.15~0.35 0.3~0.6 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.13~0.18 0.15~0.35 0.3~0.6 ≦ 0.04 ≦ 0.05
0.13~0.18 0.3~0.6 ≦ 0.04 ≦ 0.05
0.12~0.18 0.15~0.35 0.3~0.8 ≦ 0.045 ≦ 0.045
0.12~0.18 0.17~0.37 0.35~0.65 ≦ 0.035 ≦ 0.035 ≦ 0.25 ≦ 0.25 ≦ 0.25
0.15~0.2 0.6~0.9 ≦ 0.03 ≦ 0.05
0.18~0.23 0.15~0.35 0.3~0.6 ≦ 0.035 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.18~0.23 0.15~0.35 0.3~0.6 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.18~0.23 0.3~0.6 ≦ 0.04 ≦ 0.05
0.17~0.23 0.15~0.35 0.3~0.6 ≦ 0.045 ≦ 0.045
0.17~0.23 0.15~0.35 0.3~0.6 ≦ 0.035 ≦ 0.035
0.35~0.41 0.15~0.35 0.6~0.9 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.32~0.38 0.15~0.35 0.6~0.9 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.32~0.38 0.6~0.9 ≦ 0.04 ≦ 0.05
0.32~0.39 0.15~0.35 0.5~0.8 ≦ 0.045 ≦ 0.045
0.32~0.38 0.15~0.35 0.5~0.8 ≦ 0.035 ≦ 0.035
0.42~0.48 0.15~0.35 0.6~0.9 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.42~0.5 0.17~0.37 0.5~0.8 ≦ 0.035 ≦ 0.035 ≦ 0.25 ≦ 0.25 ≦ 0.25
0.42~0.48 0.15~0.35 0.6~0.9 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.43~0.5 0.6~0.9 ≦ 0.04 ≦ 0.05
0.42~0.5 0.15~0.35 0.5~0.8 ≦ 0.045 ≦ 0.035
0.52~0.6 0.15~0.35 0.6~0.9 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.52~0.6 0.15~0.35 0.6~0.9 ≦ 0.03 ≦ 0.035 ≦ 0.2 ≦ 0.2 ≦ 0.3 ≦ 0.35
0.5~0.6 0.6~0.9 ≦ 0.04 ≦ 0.05