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[sachchi007]

I am some queries regarding the material selection cluses mentioned in the API 617 for the centrifugal compressor.

Refer clause No. 2.2.1.6 and 2.2.1.9 of 7th edition.

My query is why API have provided the limitations on the max. yield strength and rockwell hardness values of the materials to be selected for the compressors.And what will be the effect if materials of higher yield strength are selecte.

Thanx in advance
Regards

[riven]

I am some queries regarding the material selection cluses mentioned in the API 617 for the centrifugal compressor.

Refer clause No. 2.2.1.6 and 2.2.1.9 of 7th edition.

My query is why API have provided the limitations on the max. yield strength and rockwell hardness values of the materials to be selected for the compressors.And what will be the effect if materials of higher yield strength are selecte.

Thanx in advance
Regards

I am not aware of the code but does it refer to any specific application. High yield steel are susceptible to hydrogen enbrittlement. Thus corrosive gases (H2S H2SO4 etc) will cause the blades to become brittle and shatter. Indeed this could happen if there is water vapour present in the air (for air compressors = always) in which carbon dioxide will dissolve and create a weak acid solution allowing the enbrittlement problem to occur.
Tho avoids this the steel is generally annealed to limit the yield strength.