Materials: APL 5L vs. ASTM A106GrB

For what are "we" using it, and at what temperature and pressure? What is it wetted with?

PWSLACK is right. For some things you could use a toiletpaper roll...

The standards are similar but it just depends on the application and the grade. A106 grB and API 5L GrB have similar dimensional and strength ratings, but the chemistry limits are slightly different (lower max carbon, Mn, Phos. and S for the API grade.). generally speaking API 5L grB will meet A106 grB but not the other way around. but there are multiple grades of API 5L too. A, B, A25 cl I and II, and it is available in seamless, ERW and butt welded flavors of each.

So mark this as a conditional yes.

It is impossible to answer this question 100% correctly without knowing what grade of APL 5L you are refering to. While it is true that you can choose a grade of APL 5L that could be safely substituted for SA106 grade B not all grades of APL 5L could be IMO. As it has already been said the safe substitution of any pipe materials and grades with another can be done as long as things such as pressure, heat rating of the piping service and chemistry etc. of the two different materials are considered and checked/matched to the codes and standards you are using. I would suggest you to go to ASME section II and compare the different grades of APL 5L with the SA106 Grade B and be sure to read all the notes.

Dear friends pipewelder, PWSlack, and Rorschach,

You are rights.