API 650 material groups

[rww88]

What is the underlying factor or factors that differentiate the API 650 material groups. This question was raised when I observed that a flush-type clean out fitting's maximum opening dimensions are dependent on material group number. I cannot find a simple definition of material group other than the API 650 table that simply lists the various acceptable material specification by group number.

 

[rww88]

Finally the answer: The API Standard 650 material groups are differentiated by the average values of longitudinal and transverse notch toughness impact values.

 

[Geoff13]

The API material Groups are only used for non-impact tested materials to determine if they're permitted by the Figure 4.1 curves. Thus the Groups reflect what temperature / thickness combinations the Code feels the materials can be assumed to meet the Table 4.5 impact test energies.

You would expect the Code would group materials with similar chemistries, mechanical properties and production methods so it's reasonable to make a common assumption for them. Some of this can be seen in the Group descriptions. Group I is semi-killed whereas Group II and above are fully killed.

 

[rww88]

Thanks Geoff13.

 

[rww88]

Geoff13 would you be interested in conducting peer-reviews of originally authored engineering topics concerning storage tanks? If so, what would be the best way for us to converse?

 

[Geoff13]

Hi rww88

I remember you're the textbook writer from another thread on this forum. Not sure how I feel about review, but I'm certain I don't want to discuss it on the forum board. Other forum sites support some form of messaging between members, but this one doesn't seem to. What do you suggest?