AUSTENITIC STAINLESS STEEL

AISI 348H

AISI 348H is listed in the AUSTENITIC STAINLESS STEEL material family. The reference data below should be checked against the governing product specification, product form and delivery condition before selection or certification.

AISI 348H
MATERIAL INTRODUCTION

AISI 348H

The reference chemistry table for AISI 348H lists Chromium (Cr): Corrosion-resistant alloying element; Nickel (Ni): Austenite stabilizer; Niobium / tantalum (Nb / Ta): Stabilizing additions. Confirm exact limits and analysis tolerances against the governing standard and product form.

The mechanical-property table for AISI 348H lists Tensile Strength: Condition and product-form dependent —; Yield Strength: Condition and product-form dependent —; Elongation: Condition and product-form dependent %; Hardness: Grade and condition dependent —. These are reference entries; supplied condition, dimensions, test method and governing specification control the requirements, and the figures are not design allowables.

Werkstoff / EN cross-reference for AISI 348H: 1.4940. This comparison does not guarantee interchangeability; confirm chemistry, product form and condition against the governing specification.

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TECHNICAL INFORMATION

Material Identification

Standard identification and material designation information for AISI 348H.

Material AISI 348H
UNS Number S34809
Werkstoff Number 1.4940
Material Type Niobium-stabilized austenitic stainless steel
MATERIAL PROPERTIES

Chemical Composition

The reference chemistry table lists Chromium (Cr): Corrosion-resistant alloying element; Nickel (Ni): Austenite stabilizer; Niobium / tantalum (Nb / Ta): Stabilizing additions. Confirm the governing standard, product analysis tolerances and product form before ordering.

Element / feature Symbol Grade information
Chromium Cr Corrosion-resistant alloying element
Nickel Ni Austenite stabilizer
Niobium / tantalum Nb / Ta Stabilizing additions
Other elements — Limits controlled by applicable specification
PERFORMANCE DATA

Mechanical Properties

The table reports Tensile Strength: Condition and product-form dependent —; Yield Strength: Condition and product-form dependent —; Elongation: Condition and product-form dependent %; Hardness: Grade and condition dependent — as reference data for AISI 348H. Actual requirements depend on condition, dimensions, test method and specification; these values are not design allowables.

Property Value Unit
Tensile Strength Condition and product-form dependent —
Yield Strength Condition and product-form dependent —
Elongation Condition and product-form dependent %
Hardness Grade and condition dependent —
MATERIAL DATA

Physical Properties

Density Typically about 7.9–8.1 g/cm³
Elastic Modulus Typically about 193 GPa
Thermal Conductivity Typically about 14–17 W/m·K
Specific Heat Typically about 500 J/kg·K
Melting Range Typically about 1370–1450°C
WHY SELECT THIS MATERIAL

Material Characteristics

AISI 348H is a stabilized austenitic chromium-nickel stainless steel designed to reduce sensitization and intergranular corrosion risk after elevated-temperature exposure. Key performance features vary by grade and condition.

01

Stabilized with Nb/Ta

AISI 348H is selected when stabilized with nb/ta is important in service.

02

Good elevated-temperature service

The grade provides good elevated-temperature service, subject to product form and specification.

03

Good corrosion resistance

This characteristic supports use of AISI 348H in appropriate industrial environments.

04

Suitable for welded construction

Performance depends on the certified material condition and governing specification.

AISI 348H Bolting Products

INDUSTRIAL USE

Typical Applications

AISI 348H is selected for bolting and engineered components where its corrosion, temperature or fabrication characteristics match the service environment.

01

General Industrial Use

Typical applications include high-temperature piping. Confirm suitability against the project specification, temperature, media and product condition.

02

Process & Chemical Service

Typical applications include pressure equipment. Confirm suitability against the project specification, temperature, media and product condition.

03

Bolting & Fasteners

Typical applications include heat exchangers. Confirm suitability against the project specification, temperature, media and product condition.

04

High-Temperature / Special Service

Typical applications include chemical processing. Confirm suitability against the project specification, temperature, media and product condition.

ENGINEERING GUIDE

Engineering Considerations

Material Selection

Consider corrosion environment, temperature, product form, fastener size, heat treatment and the governing specification when selecting AISI 348H.

Formability

Corrosion Resistance: AISI 348H is intended for corrosion-resistant service, but actual performance depends on the environment, concentration, temperature and surface condition.

Mechanical Requirements

Mechanical Requirements: use certified mechanical properties for the exact grade, product form and condition; do not substitute generic family values for design allowables.

COMMON QUESTIONS

Frequently Asked Questions

What is the Werkstoff number for AISI 348H?

The commonly listed Werkstoff / EN cross-reference for AISI 348H is 1.4940. Treat this as a grade comparison, not a guarantee of interchangeability. Verify chemistry, product form, condition and governing specification against the supplier certificate before substitution.

Where is AISI 348H used?

Typical applications include high-temperature piping, pressure equipment, heat exchangers. Suitability depends on service environment and product condition.

Are the mechanical properties of AISI 348H condition dependent?

Yes. Tensile strength, yield strength, elongation and hardness vary with product form, heat treatment, cold work, section size and the governing specification.

ENGINEERING SUPPORT

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