ISO 21635:2018

INTERNATIONAL ISO
STANDARD 21635
First edition
2018-07
Ships and marine technology —
Specification of high manganese
austenitic steel used for LNG tanks on
board ships
Navires et technologie maritime — Spécification des aciers à haute
teneur en manganèse utilisés pour les réservoirs de GNL à bord des
navires
Reference number
©
ISO 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Required specification. 2
5 Manufacture . 2
5.1 Steel-making practice . 2
5.2 Steel plates . 2
6 Chemical composition and mechanical properties . 2
6.1 Chemical composition . 2
6.2 Mechanical properties . 3
6.2.1 Requirements of tensile strength and yield strength . 3
6.2.2 Toughness requirements . 3
6.2.3 Bend test . 3
6.3 Supplementary requirements . 4
7 Test procedures . 4
7.1 Mechanical test . 4
7.2 Retest procedures . 4
8 Weldability . 4
9 Marking . 4
10 Documentation . 5
Bibliography . 6
Foreword
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This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 8, Ship design.
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iv © ISO 2018 – All rights reserved

Introduction
There have been several requirements regarding metallic materials for cryogenic applications since the
adoption of the IGC and IGF Codes. The newly developed, high manganese (Mn) austenitic steel should
possess mechanical properties including Charpy impact energy values comparable to those of materials
[1] [2]
for cryogenic service listed in both the IGC Code and IGF Code . Consequently, high Mn austenitic
steel is intended to satisfy the strength requirements of the structure of cargo tanks, fuel tanks and
piping systems of LNG carriers and LNG-fuelled ships.
This document provides a standard specification of high manganese austenitic steel for material
suppliers, ship owners, ship yards, manufacturers and shipping companies with regard to producing,
purchasing and using such materials.
INTERNATIONAL STANDARD ISO 21635:2018(E)
Ships and marine technology — Specification of high
manganese austenitic steel used for LNG tanks on board
ships
1 Scope
This document describes the specification of high manganese (Mn) austenitic steel plates to be used for
LNG tanks on board ships.
The specification of high manganese austenitic steel can be also considered for design and manufacture
of cargo tanks and process pressure vessels of LNG supply/terminal and transportation of fuels and
traded gases.
This document is primarily applicable for the specification of LNG tank
...