# Hyundai Steel gets Korea's first KS certification for fire- and earthquake-resistant H-beam SHN355FR

- Published: 2026-11-13 00:34 UTC
- Section: Machines & Making › Materials science
- Tags: Hyundai Steel, SHN355FR, KS certification, KS D 3866, fire-resistant steel, seismic H-beam, structural steel, 355 MPa yield strength, SHN-FR, Incheon plant
- URL: https://realtech.media/news/rt-cb9fd8d6da94031b836536e3_hyundai_steel_gets/

**The Incheon plant certified SHN355FR, a 355 MPa-class steel, under the revised KS D 3866, which since July 2024 includes fire- and seismic-resistant SHN-FR beams.**

![Hyundai Steel gets Korea's first KS certification for fire- and earthquake-resistant H-beam SHN355FR](https://realtech.media/media/2026/11/cd252a2501184247.jpg)
*biz.heraldcorp.com*

Hyundai Steel said on the 12th that its structural H-beam SHN355FR, which combines fire resistance and seismic resistance, has received KS certification under the standard for hot-rolled structural shapes, KS D 3866, according to biz.heraldcorp.com [1]. The company stressed that its Incheon plant is the first site in Korea to receive KS certification for fire- and seismic-resistant H-beams under the revised KS D 3866 [1].

## Properties of SHN355FR

SHN355FR is a steel of the 355 MPa yield-strength class. Yield strength is the maximum stress at which steel keeps its original shape under external force; beyond it, permanent deformation occurs. SHN355FR can withstand a load of about 36 kgf per mm² or more [1].

The product has the deformation capacity and seismic performance needed during an earthquake, and it retains strength in a fire. The company said that even when the steel temperature rises to 600°C, it keeps at least 67% of its room-temperature yield strength, which, according to the company, helps preserve structural stability in a fire [1].

## Revised standard and plans

The certification follows KS D 3866 as revised and announced in July 2024 by the Korean Agency for Technology and Standards. Alongside the existing seismic shapes (SHN), the revision added fire- and seismic-resistant SHN-FR shapes with a yield strength of 355–460 MPa to the national standard [1].

As buildings grow taller and larger, technology that addresses fire and earthquakes together is becoming more important. Hyundai Steel developed the hot-rolled structural H-beam SHN in 2005. It then released SD500S and SD600S ultra-high-strength seismic rebar and high-performance building steels such as SHN460, and in 2017 launched the seismic steel brand H CORE.

The company expects that using fire- and seismic-resistant steel will raise buildings' safety against fire and earthquakes. It also expects to use less fireproof coating material and to simplify construction, which should shorten build times.

Hyundai Steel plans to widen the strength levels and thickness range of the steel step by step, and to work on manufacturing technology that secures both performance and cost-effectiveness. A company representative said the certification is official recognition of the technology and manufacturing capability the company has accumulated over a long period [1].

## Sources

1. [biz.heraldcorp.com](https://biz.heraldcorp.com/article/10934532)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-cb9fd8d6da94031b836536e3_hyundai_steel_gets/