Qualitative and Quantitative Testing

[Sandesh Pandey]

Dear All

 

Kindly give us information about Qualitative and Quantitative Testing.
What is the difference between CTOD Test and Impact Test,Which one is Qualitative or Quantitative Testing.
 

Reply as soon as possible.

 

Best Regards

Sandesh Pandey
 

[sanggyu Lee]

It would be better if you mentioned the background of your query. Generally speaking ctod is more sophicated and more reliable than impact test. in the sense ctod could be more likely quantitative.

sang gyu lee

Sandesh Pandey <sandesh....@gmail.com>님이 작성:

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[Harish Kannepalli]

Qualitative tests are the ones which do not give any measure or value of the quantity, like microstructures, liquid penetrant test,etc. In other case, a value is given as outcome of the test like tensile test, impact test, radiography, UT,etc. So in your case both CTOD & CVN are quantitative tests, as both give a value of the measurand. Like CTOD gives the JIC,KIC and CVN energy in Joules/ft.lb

         In CTOD a predefined crack is made and its rate of growth is measured to get the fracture toughness, whereas in CVN a predefined notch is made to get the energy absorbed, also here the energy is given in a sudden single blow. I think this would clear your query.

2010/9/14 Sandesh Pandey <sandesh....@gmail.com>

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regards,

Harish.

[N VENKATESWARA PRASAD]

CTOD is Qualitative test which  gives rate of crack growth.  The rate of crack growth depends on quality of micro structue of weld.  The crack growth will be slow if it is ductile and fast it is brittle.

 

Impact test is a quanititative test which give energy abosrobed before fracture.

 

Regards

 

N.V. PRASAD

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[Norton, Seth J]

Sandesh,

 

            Impact tests measure the energy absorbed in fracturing a metal sample at high velocity and are used to quantify toughness. The crack tip opening displacement test is a fracture mechanics test which can be used to calculate the stress intensity at a sharp crack tip in the tested material as well as critical flaw sizes which will result in unstable fracture. Both tests provide quantitative results, however, the CTOD test requires additional calculations to achieve the desired output (normally a critical stress intensity).

 

Seth Norton

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[Kathalingam Babu]

Hi N.V .Prasad,

 

Both tests are quantitative only.

 

In qualitative tests, we can conclude whether the product is accepted or rejected , but not based on the specified value.

 

For example, to find the presence of iron contamination in SS by some chemical test (ASTM A380) is the qualitative .

 

Reagrds,

 

K.Babu

Singapore

 

 

 

 

----- Original Message -----

From: N VENKATESWARA PRASAD

To: material...@googlegroups.com

Sent: Wednesday, September 15, 2010 12:50 AM

Subject: Re: [MW:7009] Qualitative and Quantitative Testing

CTOD is Qualitative test (It shall be quantitative) which  gives rate of crack growth.  The rate of crack growth depends on quality of micro structue of weld.  The crack growth will be slow if it is ductile and fast it is brittle.