Where K55 belongs in a casing programme
K55 is one of the grades in the standard list this factory publishes — J55, K55, N80, L80, P110. It is named in the published grade list for the casing family; which grade an interval takes is the design engineer's load-case decision, written on the programme.
K55 is named in the published grade list; the fourteen machinable sizes from 4-1/2 in to 20 in are published as a separate size list, and the two lists are not documented against each other — a K55 line at a given size is confirmed in the quotation. Threading follows the design, not the grade: the form for each section is the one the design names — STC, LTC or BTC, or a premium pattern from the threading family — stated per line in the RFQ, and the quotation confirms whether the stated grade-and-form combination can be accepted for that line.
K55 next to its neighbours
| Grade | In the published list | How it is specified |
|---|---|---|
| J55 | Published grade | Named by the design for its interval; see the J55 page |
| K55 | This page | Named by the design; size and thread confirmed per enquiry |
| N80-1 / N80Q | Published grades | Named by the design; see the N80 page |
| L80-1 / P110 | Published grades | Named by the design; see their grade pages |
Two distinctions in the published grade list are worth stating exactly at RFQ stage. First, K55 and J55 are separate published designations: a design that names one does not accept the other by default. Second, K55 and N80 are separate designations in the same published list. State the grade exactly as your design names it, and ask for any substitution to be raised as a design change in the quotation rather than made silently inside an order.
Ordering K55 casing
A K55 enquiry needs the same five fields as any casing line: outside diameter, weight or wall, grade stated as K55, thread and coupling form, and length range, plus quantity and destination. The couplings for the string are named on their own enquiry lines, and pup joints for the string are named on theirs. Ask for MOQ, packing and lead time to be confirmed for your specification in the written quotation.
Is K55 available across the full size list?
K55 is in the published grade list for the casing family, whose machinable sizes run 4-1/2 in to 20 in. A specific size-and-grade combination is confirmed in the quotation, as with every grade on this site.
Can K55 casing take BTC threads?
Thread form is specified independently of grade, and BTC is a listed form for the casing family. State STC, LTC or BTC per string section in the RFQ, with size and weight; the quotation confirms whether the stated grade-and-form combination can be accepted for that line.
Should I choose K55 or N80?
That is a design load-case decision, taken by the design engineer against the interval's loads. Both grades are in the published list; send the well section data with the enquiry if you want the quotation to price both options separately.
Request a Quotation
Send your size, grade, thread and quantity. MOQ, packing and lead time are confirmed in the quotation for your exact specification — no generic promise replaces a written quote.