API 6 Temperature class

[Miloheinrich]

Hello ,

I wonder if someone can help me. API 6A says that a material is qualified for a temperature rating if the impact test is done at or below the lowerst temperature of the classification range. So in case a forged steel bar is made according to API 6A temperature class K ( -75F-180°F) does this mean that it is also temperature class U (0 - 250°F)? Shouldn´t there also be a test for the highest temperature?

Thanks in advance

Milo

 

[yudhichen]

hi....

let me share what i know about API6A. im using API6A 20th edition. According to table7 page 36, impact test requirement depends on PSL and temperature range. as you mention about temperature class K(-75°F to 180°F), impact test is mandatory regardless PSL requirement. for temperature class U(0°F to 250°F), it depends on PSL that you decide based on user requirement.

Table7 also mention impact value requirement at lowest limit temperature s go-no go criteria since it was done in order to ensure steel can withstand toughness property when exposed to lowest working temperature. AFAIK, i never heard impact test was done on steel at max limit temperature (normally its for minus temp).

regards

yudhi

 

[OGMetEngr]

No test if upper temperature equal to/below 250F per API 6A. What you do have to consider, per section 4.2.2.2, is:

"The design shall consider the effects of differential thermal expansion from temperature changes and temperature
gradients which the equipment can experience in service."

 

[jbeckhou]

See Annex G

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