How to convert the hardness to strength for aluminum

Written by richard rowe
  • Share
  • Tweet
  • Share
  • Pin
  • Email
How to convert the hardness to strength for aluminum
The relationship between hardness and tensile strength is all about how load travels through a crystalline matrix. (Jupiterimages/Photos.com/Getty Images)

While hardness and tensile strength aren't directly correlative, there is a well-known link between the two. The reasons behind this are complex, but have to do with the material's ability to withstand molecular shearing along certain lines of force. Metal has a crystalline structure, so when you place a load on it during a hardness test, the load transfers -- not just downward -- but out to the sides. This aspect of material-loading in metal mimics very closely the consequences of bending the material during a tensile strength test. This means that you can fairly accurately estimate the tensile strength of a material like aluminium, copper, steel, brass or iron using only its hardness rating.

Skill level:
Moderately Challenging

Other People Are Reading

Instructions

  1. 1

    Gather the data regarding your material's hardness on the 3000-kilogram Brinell scale. The material's hardness rating will vary, depending upon whether it's a pure metal or an alloy.

    For our example, we'll estimate the tensile strength of 2011-T3 aluminium. 2011-T3 has a Rockwell hardness of B60 and 3000-kg Brinell hardness of 107. If you have the Brinell hardness in a different range, refer to a hardness conversion scale to convert it.

  2. 2

    Multiply the 3000-kg Brinell rating by 515, if the Brinell reading is lower than 175. As this is the case with our 2011-T3 alloy, we'll multiply its Brinell hardness of 107 by 515 -- to arrive at an approximate tensile strength of 24995 Kilogram per square inch. Double-checking this against the ultimate tensile strength given at Onlinemetals.com, we find that our estimate is a mere 0.2-per cent off of the material's 55,000 psi rating.

  3. 3

    Multiply the 3000-kg Brinell rating by 490 -- if the Brinell rating is greater than 175. Since no forms of aluminium have a Brinell rating that high, we'll use aircraft-grade titanium. This titanium has a 3000-kg Brinell rating of 330. Multiplying that by 490 we get 161,700 psi. Titanium Era states that this alloy's tensile strength is about 150,000 psi, which is about 7.8-per cent off of our estimation.

Tips and warnings

  • Bear in mind that these formulas are for estimation purposes only. The fact is, that while there is a correlation between hardness and tensile strength; the correlation will vary depending on that particular material's crystalline structure and hardness.

Don't Miss

Filter:
  • All types
  • Articles
  • Slideshows
  • Videos
Sort:
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the eHow.co.uk site, you consent to the use of cookies. For more information, please see our Cookie policy.