Effect of hydrogen embrittlement on seamless steel pipe under high pressure

Hydrogen embrittlement refers to the fact that after the steel absorbs and diffuses hydrogen atoms, the lattice structure is embrittlement, resulting in the material losing toughness, the tensile strength and ductility are significantly reduced, and the brittle fracture is more likely to occur. In high pressure environment, seamless pipes often need to withstand greater internal and external pressure, and hydrogen embrittlement phenomenon has a particularly significant impact on their performance.

Its main manifestations are:

Reduces toughness and ductility
After the hydrogen atom enters the steel lattice, it will promote the binding force between the grains to decline, forming micro-cracks and micro-pores, making the steel vulnerable. Under high pressure conditions, hydrogen embrittlement will greatly reduce the impact resistance and fatigue resistance of seamless steel pipes, which is prone to sudden brittle fracture.

crack
The high pressure environment makes it easier for hydrogen atoms to penetrate into the pipe, and local stress concentration areas (such as uneven annealing or surface defects) are more likely to become the starting point of cracks. With the passage of time, the microcracks continue to expand under the action of high pressure, which may cause the overall fracture.

Create security risks
Hydrogen embrittlement is particularly serious in applications that transport hydrogen or acidic media (such as environments containing hydrogen sulfide). Brittle fracture caused by hydrogen embrittlement usually has no obvious warning, once it occurs, it may cause leakage or even explosion, which seriously threatens the safety and reliability of pipeline system.

The service life of the pipeline is affected
The hydrogen embrittlement phenomenon will accelerate the fatigue damage of the steel pipe and reduce the service life of the pipe. Under high pressure conditions, if the seamless steel pipe can not effectively protect hydrogen penetration, its long-term service performance will be greatly affected.

preventive measure

Control of hydrogen source: In the process of production, welding and use, strictly control the source of hydrogen to avoid working in high temperature, high humidity or hydrogen-containing media.
Optimize the heat treatment process: the appropriate annealing and normalizing process is used to eliminate the residual stress generated during the processing, while promoting grain homogenization and reducing hydrogen embrittlement sensitivity.
Surface protection and coating: By surface coating, plating or chemical passivation treatment, an insulating layer is formed to prevent hydrogen atoms from penetrating the interior of the steel. For key parts, anti-hydrogen penetration coating or thermal spraying technology can be used to enhance protection.
Regular testing and monitoring: non-destructive testing technology (such as ultrasonic, eddy current testing) is used to monitor the hydrogen embrittlement defects that may occur inside the material, and timely maintenance measures are taken. Establish a perfect quality tracking and testing system to ensure that products meet the requirements of hydrogen brittleness resistance before and after service.

Through the above multiple measures, the impact of hydrogen embrittleness on seamless steel pipes can be effectively reduced, and its long-term safe operation in the environment of high pressure, high temperature and hydrogen-containing media can be guaranteed.