304 (S30400) | BYBOLT

Grade: 304

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Each grade retains its own composition, condition and specification requirements.

What is 304 stainless steel and its applications?

304 stainless steel (UNS S30400) is a chromium-nickel austenitic grade used for equipment exposed to many everyday industrial environments. It combines formability and corrosion resistance in food equipment, general plant hardware and non-marine architectural components.

Food-handling equipment: Frames and equipment components with specified cleaning and surface-finish requirements.
General industrial assemblies: Covers, brackets and machinery connections in moderately corrosive environments.
Architectural hardware: Indoor and non-marine exterior fittings where appearance and exposure must be considered together.

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Choose your 304 product

Engineering Application & Selection Guide

Chromium supports the passive surface film, while nickel stabilizes the austenitic structure. Cold working can increase strength; a 304 chemical certificate alone does not identify the mechanical properties of a finished bolt.

304 hex bolts — For routine machinery joints, specify the required mechanical property class as well as the alloy designation.
304 socket head cap screws — For frequently serviced covers, define lubrication and installation practice to limit thread damage.
304 hex nuts — Match nut load capacity and thread tolerance to the bolt rather than choosing a pair solely because both say 304.

Choose between 304 and 304L on the actual fabrication and certification requirements. If chlorides govern corrosion, compare 316L and more resistant alternatives. A stainless grade is not a blanket approval for seawater exposure.

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304 Composition

Selected typical composition · wt.%

ElementWeight %

Cr: 18.1%
Ni: 8.1%
C: 0.04%

ASTM / ASME specifications by product form

Finished-product requirements

Specify the finished-fastener mechanical requirements, condition and inspection separately from the starting-stock specification.

304 hex bolt requirements ↗

Fasteners · dimensional references

Product	Reference
Hex bolts	ISO 4014 / ISO 4017 · ASME B18.2.1
Threaded studs	DIN 976-1 · ASME B18.31.2
Hex nuts	ISO 4032 · ASME B18.2.2
Socket head screws	ISO 4762 · ASME B18.3
Flat washers	ISO 7089 / ISO 7090 · ASME B18.21.1
Custom fasteners	Customer drawing

Raw-material specifications

Product form / scope	Reference
Bar & shapes · Specify grade, condition and order requirements.	ASTM A276

Dimensions do not define material or finished-part compliance. Specify the grade, condition and applicable requirements.

How to specify round bar, plate, wire and strip ↗

304 Mechanical Properties

Reference sample and condition

Data basis: Producer typical reference
Test sample form: Hot-rolled quarto plate
Test temperature: Room temperature
Gauge length: A5

Key properties	Value
Tensile strength	600 MPa
0.2% yield strength	270 MPa
Elongation	55%

Outokumpu · Stainless Steel Handbook · Tables 2:1, 2:2, 7:5 & 7:6 · PDF pages 52–53 for tensile values; hosted by SCI ↗

Procurement and application guide

Specify the material and final condition

Specify the required condition and fastener property class separately.

Material forms in the technical reference: Plate · Sheet · Strip · Bar · Shapes.

Define the finished-part acceptance

Include the material or bolting specification, required final condition, dimensions and quantity. State the service medium, temperature and loading where known. Agree the required tests, inspection coverage and acceptance criteria for the finished part.

Start with the information you have

Send a drawing or share the product form and dimensions. Identify any undecided requirements for review rather than copying a typical property value into the purchase order.

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