What is the difference between P355GH and P355NH

P355GH and P355NH are both steel grades for pressure vessel applications, but they have some key differences:

1. P355GH:
- P355GH is a non-alloy quality steel with specified elevated temperature properties, typically used in high-temperature industrial applications.
- It is primarily used for pressure vessels and boilers operating at moderate to high temperatures.
- P355GH is normalized fine-grain steel with good weldability and excellent toughness.

2. P355NH:
- P355NH is a normalized fine-grain steel with specified low-temperature properties, designed for use in low-temperature pressure vessel applications.
- It offers good impact toughness at low temperatures, making it suitable for cryogenic applications.
- P355NH has enhanced strength compared to P355GH due to its normalized condition.

In summary, the main difference between P355GH and P355NH lies in their intended applications and working conditions. P355GH is suitable for high-temperature environments, while P355NH is designed for low-temperature service, offering better impact toughness at lower temperatures.