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What Is Rockwell Hardness of 304 Full Hard

what is rockwell hardness of 304 full hard

The Rockwell hardness is one of the best techniques for checking the hardness of 304 full hard stainless steel. There are some other measuring systems for calculating the hardness of stainless steel, like Brinell hardness and Vickers hardness, in different value ranges. The Rockwell hardness is a very precise and well-known non-destructive metallurgical testing system among them. With the help of this testing method, we can determine whether the material is hard or soft.

The two brothers Stanly P. Rockwell and Hugh M. Rockwell invented the Rockwell hardness testing system in the early 1900s. In 1914, Stanley Rockwell obtained a patent for his testing technique. He updated the patent in 1919 to add the Rockwell scale chart. The most commonly used scales are scale C and scale B.

This guide is very helpful if you want to learn more about the Rockwell hardness of 304 full hard stainless steel.

What is full hard 304 stainless steel?

The full hard 304 stainless steel is a Nickel-Chromium alloy, which belongs to the austenitic stainless steel group. Full hard 304 stainless steel has high ductility and excellent forming and drawing properties. It has better corrosion resistance than grade 302 stainless steel. It is non-magnetic, but it got magnetic properties after cold working.

304 full hard is mostly resistant to salt spray and oxidizing acids. It has low carbon content; therefore, it reduces pitting corrosion susceptibility and the amount of carbide that precipitates in the heat-affected zone during welding.

Which hardness test is most widely used?

The Rockwell hardness testing system is most widely used due to its easy testing method and precise results. Rockwell’s method of testing is replaced older metal testing methods such as the time-consuming Vickers test and the overly damaging Brinell metal test, particularly for small parts.

Rockwell is the successful testing system has the following factors:

  • The system needed to be simple to purchase and keep up with.
  • The least harmful testing tools are required.
  • Testing apparatus required simple implementation.
  • It made operator oversight and training simple.
  • The testing staff has to follow clear, documented standards.
  • Users could get useful information from test findings.

The Rockwell hardness testing method fulfills all the requirements for the hardness testing of 304 stainless steel and all other grades of the austenitic stainless steel family. It is a very old method but still the best. You can see the scales of the Rockwell hardness in the following table.

Rockwell hardness scales and applications

ScaleAbbreviationLoad  Kgf (1 Kgf is equal to 9.80665 N)IndenterApplication
AHRA60120-degree diamond coneCemented carbides, case-hardened steel
BHRB1001.588 mm steel sphereCopper alloys, soft steel, aluminum alloys
CHRC150120-degree diamond coneSteel, hard cast iron, titanium, deep case hardened steel
DHRD100120-degree diamond coneThin steel, medium case hardened steel
EHRE1003.175 mm steel sphereCast iron, aluminum, and magnesium alloys
FHRF601.588 mm steel sphereAnnealed copper alloys, thin soft sheet metals
GHRG1501.588 mm steel sphereBeryllium copper, malleable irons
HHRH603.175 mm steel sphereAluminum, zinc, lead
KHRK1503.175 mm steel sphereVery soft or thin materials, bearing materials

What is the Rockwell hardness of 304 full hard?

Rockwell hardness testing system is a quicker and more reliable method for checking the hardness of 304 full hard stainless steel. It is preferable for both large and small-volume work pieces due to the relatively high load. The values of Rockwell hardness for all the temper conditions of 304 stainless steel can see in the following table.

Temper condition of 304Rockwell hardness B HRBRockwell hardness C HRC
1/4  Hard95-10016-22
Half hard100-10622-31
3/4 Hard106-10931-38
Full hard38-41

Properties of 304 full hard stainless steel

304 full hard stainless steel is mostly used in industries due to its outstanding properties like excellent corrosion resistance and strength.

Mechanical properties

Mechanical properties  Full Hard 304
Tensile strength Min  MPa1280
Yield strength 0.2% Min MPa965  
Shear strength MPa690
Fatigue strength MPa440
Poisson’s ratio0.29
Fatigue strength MPa77

Thermal properties

Thermal properties304 Full hard
Latent heat of fusion J/g290
Maximum temperature corrosion °C420
Maximum temperature mechanical °C710
Specific heat capacity J/kg-K480
Thermal conductivity W/m-k16
Thermal Expansion µm/m-K17

Physical properties

DensityMelting rangeModulus of Elasticity
8.03 g/cm31400-1455 °C193 GPa

Chemical composition


Applications of 304 full hard stainless steel

The 304 stainless steel is the most widely used material in many applications like:

  • Architectural panels
  • In the production of pharmaceutical equipment
  • Brewery and food industry
  • Screws, bolts, nuts, and springs
  • Beer kegs, bellows, chemical apparatus
  • Coal hopper linings, evaporators,
  • Feed water tubing, flexible metal hose,
  • Hospital surgical apparatus,
  • Hypodermic needles, kitchen sinks,
  • Marine apparatus and fasteners, nuclear equipment, oil well filter screens, refrigeration apparatus, paper industry, pots and pans, pressure vessels, sanitary fittings, valves, and equipment for textile dyeing.

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