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UNS S30400 Austenitic Stainless Steel

What is UNS S30400? This grade of steel is an austenitic stainless steel. It is the most common grade of stainless steel, offered in an extensive types of variants, forms and surface finishes than any other type of stainless steel.

What is ASTM A240 / A240M? It is an American standard for Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications. UNS S30400 is referred in ASTM A240 as 304 grade steel.

Why S30400 called Alloy 304 Stainless Steel? Alloy 304 is a common market name for UNS S30400. Many international material standards refer UNS 30400 stainless steel as 304. For example the Japanese standard JIS G4303 also refers this grade as SUS304. UNS S30400 is ideally used for home and commercial applications.

This grade of steel is said to have robust forming and welding properties. The equilibrium of austenitic of Grade S30400 allows it to be steadily deep drawn even if it not being annealed, which has founded this grade prevalent in the production of drawn stainless parts for example saucepans, sinks, pots and other accessories that are hollow-ware. For such uses it is good to utilize special type of UNS S30400 i.e. also known as deep draw quality. 304DDQ is the market name of deep draw quality of this grade and it’s a variant within this.

Available Forms in Market: Following are the available forms of S30400 steels in the global market:

  • Sheets Coils
  • Cut to length Sheets
  • Slit Coils
  • Plates
  • Tabular Products
  • Round bars

Dimensional Characteristics of S30400 Steels: The applicable thickness for this S30400 material as obtained by data in the market starts from 0.38 mm to 35 mm. However the width of this material ranges to 660 mm and over.

The Indicative Chemical Composition of S30400 Steels:  The chemical composition of this grade is indicated as under:

  • Maximum percentage of Carbon (C) is 0.08 percent.
  • Maximum percentage of Manganese (Mn) is 2.0 percent.
  • Maximum percentage of Phosphorous (P) is 0.045 percent.
  • Maximum percentage of Sulphur (S) is 0.030 percent.
  • Minimum percentage of Chromium is 20.0 percent
  • Minimum percentage of Nickel is 5 percent from 8.0 percent.
  • Maximum percentage of Silicon (Si) is 0.75 percent.
  • Maximum percentage of nitrogen is 0.10 percent.

Remaining is iron (Fe) percentage and with few negligible impurities.

Mechanical Properties of S30400 Steels: Following are some of the mechanical properties of 304 (18/8 stainless) steels:

  • The tensile strength of the 254 alloy steel is expressed in Newton per millimeters and it must be at-least 515 N/mm2 (MPa).
  • The elongation property of S30400 steel varies with the heat treatment process but it indicated typically 40% at break.
  • S30400 has excellent welding property.
  • The Brinell hardness is indicated around 201.
  • Good Corrosion resistance in normal environment but susceptible to crevice and pitting in warm chloride atmosphere. For warm chloride environments, UNS S31254 can be used.

Equivalent Material Grades in Other International Standards: Read more about the

Applications of S30400 Stainless Steels: Applications are as under

  • Feedwater tubes
  • Chemical containers
  • Kitchen equipment
  • Process equipment in chemical industry
  • Flue-gas cleaning
  • Desalination
  • Heat exchangers

Suppliers of S30400 Steel: Suppliers are also listed below:

Supplier AK Steel Corporation bearing contact number 800-331-5050.The supplier address is 9227 Centre Pointe Drive, West Chester, OH 45069

Supplier Penn Stainless Steel bearing contact number 215-536-3053.The supplier address is 190 Kelly Road Quakertown, PA 18951


Waqas Imam is an Industrial Engineer, Certified Lead Auditor, Material Consultant and Blog Writer.

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