used ASME flanges as conventional flanges . There are other flange designs in the market , such as DNV compact flanges whereby one can refer to the NORSOK Standard L-005 for the desired tightening value . On top of that , there are various “ Clamp Connectors ” in the market that can be used as substitute flanges . It is therefore crucial for engineers to study and understand the manufacturing specifications and ensure suitability before utilising the product .
As mentioned earlier , gasket cold flow is meant to seal off the flange mating surface , including minor defects on the flange profile . Thus , a suitable gasket needs to be selected for the job per the pressure rating and flange surface design . Generally , there are three categories of gaskets used in our industry , namely soft nonmetallic gasket ( e . g . aramid fibre / neoprene rubber ), composite spiral wound gasket , and metal ring gasket ( e . g . RTJ ) for pressure rating
of low , medium , and high respectively . The metal ring gasket is non-compressible , and per Newton ’ s 3 rd law , the said gasket will exert the same force back to the stud bolt during tightening . Safety Factor may be used to prevent damaging the stud bolt .
PERSONNEL QUALIFICATION ( Joint Assembler )
One may have the best procedure , process , and equipment in place but without the correct skill set , the work is still error-prone . Therefore , individual qualification can be another area of consideration . For example , ASME CPP- 1 Appendix A recommends a Qualification Programme which comprises training , demonstration , and examination ( practical and written ) to evaluate the skills of the personnel .
Sample Stress-Strain Curve for Steel
Note :
In general , plastic deformation occurs when the steel material exceeds the “ Elastic limits ” ( left ), and the material is unable to return to its original shape .
Adapted from : www . twi-global . com / technical-knowledge / job-knowledge / mechanical-testing-tensiletesting-part-1-069
General Information :
● Newton ' s third law states that for every action ( force ) in nature , there is an equal and opposite reaction ( force )
● Asbestos-type gasket ( crocidolite ) is banned in Malaysia per OSHA 1994 , Occupational Safety and Health ( Prohibition of Use of Substance ) Order
● Stainless Steel Bolts are discouraged in salty environments , particularly offshore platforms , due to the Chloride Stress Corrosion Crack ( CSCC ) effect in which the bolt can break without any warning signs .
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