304 Stainless Steel

304 stainless steel is standard 18/8 Austenitic stainless steel, it contains both Chromium (usually 18%) and Nickel (usually 8%) metals as the main non-iron constituents, 304 stainless steel has good weldability, corrosion resistance, heat resistance, low temperature strength and mechanical properties and good hot workability, it is not very electrically or thermally conductive, these properties make it become the most familiar and most frequently used alloy in the stainless steel family.

304 Stainless Steel Overview

  • The most used stainless steel
  • Typical 18/8 Chromium-Nickel stainless steel
  • Make up: beside chromium and nickel elements, Carbon, Silicon, Manganese, Phosphorus, Sulfur are added.
  • It is non-magnetic stainless steel in the annealed condition.
  • It is food grade stainless steel
  • Aka, AISI 304, T304, TP 304, SUS304, SS304, 304SS, 304 SS, UNS S30400
  • More forms and finishes
  • Can be used in the most conditions due to excellent properties

304 Stainless Steel Chemical Composition:

GradeCMnPSSiNiCrNFe
TP3040.082.000.0450.0301.08-1118-20Bal.
SUS3040.082.000.0400.0301.08-10.518-20Bal.
1.43010.072.000.0400.0151.08-10.517-19.50.11Bal.

304 Stainless Steel Mechanical Properties:

Tensile Strength(Mpa) MaxYield Point(Mpa) MaxElongation(%)Hardness (HRB) Max
TP3045152053592
SUS30452020535
1.4301500-70019540

304 Stainless Steel Equivalent Grades

AISIUNSDINENJISGB
304304001.4301X5CrNi18-10SUS30406Cr19Ni10

澳门凯发娱乐Specifications reference: ASTM A240, JIS G 4303, EN 10088-1, GB/T 20878, there material are possible alternative grades, in the most cases, these materials can be replaced each other.

304 Stainless Steel Physical Properties

Density Melting Point Specific heat Thermal conductivity [W/(m·K)] Coefficient of Expansion( 10-6/K ) Electrical Resistivity Elastic modulus
g/cm3 (℃) [J/(kg·K)] 0~100 ℃ 100 ℃ 500 ℃ 0~100 ℃ 0~500 ℃ ( NΩ.m kN/mm2
7.99 1398~1427 500 16.3 21.5 16.6 18.6 720 193

Physical properties of 304 stainless steel in the annealed condition and room temperature if not stated.

Magnetic

Type 304 stainless steel is not magnetic due to Austenitic structure, but may be slightly magnetic after cold working.

Heat Resistance

Stainless steel 304 has good resistance to oxidation in intermittent service up to 870°C and in continuous service to 925°C. However, continuous use at 425-860°C is not recommended, 304l stainless steel is recommended due to its resistance to carbide precipitation, where high strength is required at temperatures above 500°C and up to 800°C, grade 304H stainless steel is recommended due to its high carbon content (0.04 – 0.10%).

Heat Treatment

Annealed to 1010-1120°C and cool rapidly, 1040 °C is recommended, 304 cannot be hardened by thermal treatment, it can only be hardened by cold working。

Welding

澳门凯发娱乐304 stainless has excellent weldability in both with and without filler metals, it does not require preheating.

Corrosion Resistance

澳门凯发娱乐304 stainless steel has excellent corrosion resistance in a wide range of atmospheric environments and many corrosive media. Pitting and crevice corrosion can occur in chloride environments, Stress corrosion cracking (SCC) can occur at temperatures over 60°C.

When 304 stainless steel is too sensitive to pitting or crevice corrosion by chlorides or general corrosion in acidic applications, it is commonly better to use 316/316L stainless steel.

Rust

In common situation, standard 304 stainless steel is not rust, it has good corrosion resistance and oxide resistance characteristics.

However, in some very harsh environment, it can be stain, like chloride exist condition, and corrosion occur fast. If base metal is not perfect, it may be rust too.

Applicable Specifications

Forms

304 stainless steel can be produced in various forms。

  • Tube
  • Pipe
  • Plate
  • Sheet
  • Strip
  • Bar
  • Fitting

Applications

AS the most used grade, 304 stainless steel has excellent forming and welding characteristics to the most cases

  • Household products
  • Auto parts
  • Medical equipment
  • Building materials
  • Chemicals
  • Food process
  • Agriculture
  • Ship parts
  • Heat exchanger

304 vs. 304L Stainless Steel

The key difference between 304 and 304L stainless steel is the carbon content, 304 contains max 0.08% of carbon content while 304 has max 0.03%, generally 304L is considered as low carbon of 304, other alloy elements are the same proportion, low carbon content gives 304L better property to resist corrosion, of course, there are slight differences in mechanical properties.

304 and 304L stainless steels are usually used as dual certified grade 304/304L, these items have chemical and mechanical properties complying with both 304 and 304L.

304 vs. 316 Stainless Steel

304 and 316 stainless steel are the first and second most used stainless steel grades respectively, they naturally draw comparisons, reading more details about 澳门凯发娱乐difference between 304 and 316.

It is not easy to judge which grade is better, it depends on some conditions, such as cost, application, lifetime。

316 and 304 stainless steel, which one is more expensive?

316 is higher price due to more Molybdenum and Nickel content added.

Hardness of 304 Stainless Steel

  • ≤187HB;
  • ≤90HRB;
  • ≤200HV

Is 304 Stainless Steel Good for Knife?

304 stainless steel is relatively soft compared to some 400 series grades。 which are more suitable material for knife, like 410, 420 and 430, and lower cost。

Is 304 Stainless Steel Good in Salt Water?

Although 304 stainless steel has overall excellent corrosion resistance, however, 304 stainless steel is not recommended to use in salt water or marine use, it will not withstand corrosion for very long and corrode very quickly, 316/316 or 2205 grade is better choice.