Austenitic Stainless Steel Composition for Hydrogen Equipment Bonding

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Solution Overview

Problem

Existing austenitic stainless steels lack adequate hydrogen embrittlement resistance (HGE) and diffusion bonding properties, particularly when diffusion bonding is required for manufacturing hydrogen-related equipment.

Innovation Solution

An austenitic stainless steel material with a specific chemical composition and passivation film, including controlled f value and cation fractions, to enhance HGE resistance and diffusion bonding properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If austenitic stainless steel is used to suppress hydrogen embrittlement, then HGE resistance is improved, but diffusion bonding properties deteriorate

Engineering Contradiction:
Improvehydrogen embrittlement resistanceVSAvoiddiffusion bonding properties
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling the chemical composition parameters (Ni: 7.0-9.0%, Mn: 8.0-10.0%, Cr: 15.0-18.0%, N: 0.15-0.25%) and the f value (29.5-32.5) to achieve both improved hydrogen embrittlement resistance and diffusion bonding properties. This systematic parameter optimization resolves the contradiction by finding the optimal balance point where both requirements are satisfied simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Strength

If welding is used to bond members, then bonding strength is improved, but shape change increases

Engineering Contradiction:
Improvebonding strengthVSAvoidshape change
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent inverts the conventional bonding approach by selecting diffusion bonding instead of welding. While welding provides strong bonding but causes significant shape change, diffusion bonding accepts slightly lower bonding strength in exchange for minimal shape change, which is critical for hydrogen-related equipment requiring high dimensional accuracy. This inversion of the bonding method selection resolves the contradiction.

Inventive Principle:
Principle #13The other way round (Inversion)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The steel exhibits excellent HGE resistance and diffusion bonding properties, suitable for manufacturing hydrogen-related equipment with improved dimensional accuracy and bonding strength.

Implementation Method 1

which has a passivation film on a surface

Methodology Applied
Scientific EffectPassivation:

Implementation Method 2

the diffusion of atoms between interfaces is utilized to perform bonding

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentUS12435402B2Austenitic stainless steel material
Publication Date: 2025.10.07 NIPPON STEEL STAINLESS STEEL CORP

AI summary

An austenitic stainless steel material that has a passivation film on a surface is provided. The austenitic stainless steel material has a chemical composition consisting of, in mass %, C: 0.10% or less, Si: 1.0% or less, Mn: 8.0-10.0%, P: 0.030% or less, S: 0.003% or less, Cr: 15.0-18.0%, Ni: 7.0-9.0%, N: 0.15-0.25%, Al: 0.005-0.20%, Ca: 0.0005-0.01%, Cu: less than 1.0%, Mo: less than 1.0%, B: 0-0.0050%, Nb: 0-0.50%, Ti: 0-0.50%, V: 0-0.50%, W: 0-0.50%, Zr: 0-0.50%, Co: 0-0.50%, Mg: 0-0.005%, Ga: 0-0.005%, Hf: 0-0.10%, REM: 0-0.10%, and the balance: Fe and impurities. An f value, namely, [Ni+0.72Cr+0.88Mo+1.11Mn−0.27Si+0.53Cu+12.93C+7.55N], is more than 29.5 and less than 32.5.