Application advantages and scenarios of high carbon steel seamless pipes

High carbon steel seamless pipes refer to seamless steel pipes made of high carbon steel as the main raw material. High carbon steel seamless pipes (usually 0.6%~1.7% carbon content) have important applications in specific industrial fields due to their high strength, high hardness and wear resistance, but they also need to be carefully selected due to their low toughness and poor weldability. This article mainly discusses the application advantages, typical application scenarios and precautions of high carbon steel seamless pipes.

Advantages of high carbon steel seamless pipes:

1. High strength and high hardness
High carbon steel seamless pipes have high strength and hardness, and can maintain their physical and mechanical properties under high temperature and high pressure environments.

The tensile strength can reach 800~1200MPa (after heat treatment), which is 2~3 times that of low carbon steel.

The hardness can reach HRC 50~65 (quenching + low temperature tempering), which is significantly better than ordinary carbon steel (HRC 15~25).

2. Excellent wear resistance
The high-carbon martensitic structure can resist abrasive wear, and the volume wear rate is 30%~50% lower than that of medium carbon steel.

Particularly suitable for:
Mining pipelines (lifespan of 6~12 months, ordinary steel pipes only 2~3 months)
Agricultural machinery tool guide rails (annual wear <0.5mm)

3. Seamless structure reliability
High carbon steel seamless pipes are manufactured by seamless process, with smooth inner and outer surfaces, not easy to produce oxide scale and surface cracks, thus increasing the service life of steel pipes.
There is no weak weld zone, and the bursting pressure is 20%~35% higher than that of welded pipes of the same specification.

Applicable to:
High-pressure hydraulic system (working pressure ≥30MPa)
Fatigue load components (such as connecting rods, cycle life is 3 times higher than that of welded pipes)

4. Dimensional stability
After low-temperature tempering, the residual austenite is <5%, and it is not easy to deform over time.
The straightness of precision cold-drawn tubes can reach 0.3mm/m, which meets the requirements of measuring tool manufacturing.

5. Good heat treatment responsiveness
Excellent hardenability (water quenching critical diameter can reach 15~25mm)

Gradient performance can be obtained through simple quenching and tempering:
Surface hardness HRC 58~62 (wear resistance)
Core hardness HRC 35~45 (impact resistance)

6. Good processing performance
High carbon steel seamless pipe has good processing performance and is easy to cut, weld, bend, etc. Among them, cutting mainly adopts flame cutting and plasma cutting; welding mainly adopts arc welding, gas welding, submerged arc welding, etc.; bending mainly adopts cold bending and hot bending.

Application areas of high carbon steel seamless pipe:

1. Mechanical manufacturing and tools
Hydraulic prop/cylinder:
Used in the hydraulic system of heavy machinery (such as excavators, injection molding machines), using the high compressive strength of high carbon steel (up to 800MPa or more) to withstand frequent high-pressure impact.

Transmission shaft and connecting rod:
High hardness (HRC 50~60) is suitable for low-speed and high-torque transmission parts, but surface quenching treatment is required to improve fatigue life.

Mold sleeve:
Such as the guide sleeve of cold stamping mold, the wear resistance is better than ordinary carbon steel.

2. Wear-resistant scene
Mining equipment:
Transportation pipelines (such as slurry pipes) and crusher liners need to be combined with carburizing treatment to improve surface wear resistance.

Agricultural machinery:
Harvester blades and plowshare sleeves are resistant to soil and crop friction.

3. Automobile industry
Suspension parts:
High-stress suspension arms of some commercial vehicles (need to be tempered to improve toughness).

Clutch shaft:
High-rigidity seamless pipes are used for high-torque transmission, but welding should be avoided (flange connection is used instead).

4. Special industry
Bearing ring blanks:
GCr15 and other high-carbon chromium steel seamless pipes are forged to make bearing rings.

Tools and measuring tools:
Such as saw blade backing materials and caliper sleeves, they rely on the dimensional stability of high-carbon steel.

Use with caution:

1. Low temperature environment
It is brittle (high ductile-brittle transition temperature), easy to crack below -20℃, and low-carbon alloy steel (such as 16MnDR) should be used instead.

2. Welding structure
Cold cracks are easy to occur during welding, and preheating (200~300℃) and low-hydrogen welding rods must be used.

3. Corrosive environment
Poor corrosion resistance, galvanizing, plastic coating or stainless steel (such as 304) is required in humid or acidic media.

Precautions for selecting high-carbon steel seamless pipes:

a. Preferred seamless process
Hot-rolled pipes (low precision but strong pressure bearing) or cold drawn pipes (precise size, used for precision parts).

b. Wall thickness design
The wall thickness in high stress environment needs to be ≥5mm to prevent brittle fracture.

c. Cost trade-off
The price of high-carbon steel pipes is 20%~30% higher than that of low-carbon steel, but the life can be increased by 2~5 times (wear-resistant scenario).

Conclusion:

High carbon steel seamless pipes are suitable for non-welded structures with high stress, low impact and wear resistance, but the heat treatment process and working conditions must be strictly controlled. In corrosive, low temperature or dynamic load environments, the comprehensive cost-effectiveness of alternative materials should be evaluated.

Read more: Types of seamless carbon steel pipes or American standard seamless steel pipe