relevant wall thickness

[lidbasky]

Hi

I work on casting that has different wall thickness in different areas of casting. How I can determine the relevant wall thickness of a casting?

 

[Eddycurrentguy]

Relevant is a subjective term.

Do you mean nominal, or thinnest that a section can be to maintain structural integrity? In any case, the fabrication drawing should have this information specified.

 

[arunmrao]

You will have to consider each section individually while designing your gating and feeding systems. There is no such concept as average or nominal thickness for varying section thickness casting. Also,if mechanical properties are checked you could observe variations. If you tell us more,perhaps someone will guide you better.

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[lidbasky]

In standard prEN 1563: 2010 section 8 (Size of test sample) was written

"The size of the sample shall be in correspondence with the relevant wall thickness of the casting",
In the definition of relevant wall thickness was written:
section of the casting, to which the determined mechanical properties apply.
so I need to know relevant wall thickness to choose a correct test sample.

 

[arunmrao]

This will depend on what the customer wants. Most probably it would be from the thick section of castings. However,please check with the customer.

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[lidbasky]

Thank you arunmrao, but I am the customer of part and in the drawing of the casting, there is no guide for relevant wall thickness.
Are you sure that it is the thick section of castings?

 

[arunmrao]

Yes,all defects and imperfections,grain coarsening etc ,gas porosity are normally related to thick section of the castings. There will be a variation in mechanical properties between those tested from standard test bars and those samples removed from thick section of the casting. If you are interested,perhaps I can look up and let you know.

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[salmon2]

Yes, for mechanical testing purpose, thickest cross section will give you biggest variance. If for pressure rating purpose, the smallest wall/od ratio is where you want to check.

 

[lidbasky]

I should mention that
The sample is cast separately as a Y block or Kill block. The size of Y block is related to relevant thickness of casting. In standard there is table for choosing test block dimension regarding to casting relevant thickness.

 

[arunmrao]

Keel blocks have only one thickness about 32 mm,they are not varying. Y blocks are used more in cast irons . I have provided a link for you,please refer to it,you may find it useful.

" Test coupons and casting properties."

http://www.sfsa.org/sfsa/pubs/testcoupons/tc.pdf

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year