High-temperature pipe · ASTM A335 P11
A335 P11 is a chromium-molybdenum alloy pipe for high-temperature service. Unlike a general carbon pipe, the buying decision here is not settled by the grade name alone — the design temperature and service, the heat-treated condition the pipe is supplied in, the tests the order carries and how the joints will be welded and treated afterwards all move together. The gate below works through those inputs so the enquiry reaches the desk complete, rather than discovering a gap at the weld.
Price on request. We publish no allowable stress, PWHT value or service limit — those follow the governing edition and your project's design code, and are confirmed against the requirement you state.
Design basis
Temperature, pressure and the service the line carries.
Grade
A335 P11 confirmed against the family, not assumed.
Condition & tests
Heat-treated condition and the ordered test package.
Weld planning
Joint procedure, PWHT and inspection, agreed early.
Condition and fabrication gate
Four of these are required before a high-temperature enquiry can be reviewed at all. The gate reports what you have stated and what is still open — it deliberately will not supply a design temperature, a heat-treatment value or a welding procedure on your behalf, because each of those comes from the governing edition and your project's design code.
Four items must be stated before this enquiry can be reviewed
Design temperature and service, the exact grade, the governing edition and the required condition and test package decide everything downstream. Work down the gate; it reports what is stated and what is still open, and it will not supply a design temperature or a treatment value for you.
0 of 5 items stated. The gate confirms that the inputs exist — it never asserts an allowable temperature, a PWHT value or a welding procedure.
Gate record
ASTM A335 P11 pipe — condition & fabrication gate record Temp & service: [REQUIRED — NOT STATED] Grade: [REQUIRED — NOT STATED] Edition: [REQUIRED — NOT STATED] Condition: [REQUIRED — NOT STATED] Weld & PWHT: [open — to be supplied] Supplier: Noor Deira Steel Trading L.L.C. — sales@noordeirasteel.ae — office +971 56 398 0860 Governing edition, heat-treated condition, test package and acceptance criteria to be confirmed at quotation.
A chromium-molybdenum joint carries three decisions at once — the welding procedure, the heat treatment that follows it and the examination the joint receives. How those are fixed is a design-code question for whoever owns the fabrication, which is why the gate asks for the scope rather than offering a procedure of our own.
Where P11 sits in the A335 family
Buyers often ask about them together because one specification covers them all. That is exactly why they are easy to muddle on a requisition — the grade drives the welding procedure, the treatment after welding and the testing the order carries, so it has to come from the design basis rather than from what was quoted last time.
P11
This grade
A chromium-molybdenum alloy grade within A335, intended for high-temperature service. The design temperature, the delivered heat-treated condition and the test package are the inputs that shape a P11 order.
Confirm P11 came from your design basis, not from a previous requisition.
P22
Another grade in the family
A separate chromium-molybdenum grade under the same specification, used across a different part of the high-temperature range. It is not an upgrade path from P11 — it is a different material designation reached for its own design reasons.
Moving to P22 changes the weld procedure and treatment basis with it.
P91
A higher-alloy grade in the family
A further grade covered by A335, drawing on different alloying and its own fabrication controls. Selecting it belongs to a design decision about the duty, not to a supplier's preference for what is on the shelf.
A higher-alloy grade is not a drop-in for P11 — the joint discipline differs.
A reasonable fit when
Revisit the basis when
Read the surrounding grades before you settle this one — A335 P22 and A335 P91 sit in the same specification but not at the same point in the high-temperature range, and the A335 alloy pipe specification is where the whole family is organised.
Evidence and testing
On a high-temperature line the certificate is read against three things at once — the grade and edition the order invoked, the condition the pipe was supplied in, and the tests the order actually carried. Each record below answers one of those questions, and none of them happens unless the order asks for it.
The chemical and mechanical results for the heat, issued against the grade and the edition the order invoked — the core evidence a P11 requirement is read against.
The link that ties the certificate to the pipe you received. Without it the chemistry and mechanics describe some heat rather than your heat.
The tension and hardness results the order and the governing edition call for, performed on the basis those actually specify rather than assumed from the grade name.
How the pipe is supplied after its heat treatment, evidenced so the fabricator's welding and treatment plan starts from a known condition.
Outside diameter, wall and length confirmed against the ordered dimensions and the standard's own tolerance provisions — which are read from the edition, not invented here.
The pipe and bundle markings that let the whole record set be read back against the consignment on receipt, grade by grade.
Where A335 P11 genuinely applies
P11 is a service-driven purchase. These are the duties where it fits — not a claim that every hot line calls for an alloy grade.
We do not publish allowable stresses, service limits or PWHT values for this grade. Those follow the governing edition of the specification together with your project's design code, and they are confirmed against the requirement you state rather than quoted as a headline figure here.
GCC markets
Destination changes the commercial and documentary side of the order, not the acceptance basis. Choose the market to see what each destination expects before the consignment is released.
The product form this grade belongs to. If the pipe type, manufacturing route or standard family is still open, settle it on the hub before the grade — the ordering discipline is the same, but the acceptance criteria are not.
Project coordination and release documents.
Confirm the design temperature, grade, edition and test package against the project requirement, then plan release to site, stockist or fabricator.
Specification alignment and import papers.
State the grade, governing edition and ordered testing alongside the delivery base so the offer matches the requirement.
Requirement and delivery window.
Confirm dimensions, test scope, quantity and delivery window so the documentation plan stays aligned to the order.
Delivery basis and documentation.
Give the delivery point and Incoterm so the certificate and release paperwork can be arranged against the order.
Contract terms and certificates.
Settle the certificate set and heat traceability before quotation — it is the field most often left open on an alloy enquiry.
Energy and process supply.
Provide the destination, the required records and a delivery date so the offer can be fixed against your inputs.
These market pages are procurement destinations, not a claim of premises in each country. Supply is coordinated from Dubai and delivered against the destination and delivery date you state.
Compare and verify
An alloy grade is frequently specified where a carbon specification was actually meant, or the reverse. These are the neighbouring standards worth checking — together with the references that help you settle the order before it reaches the desk.
The chromium-molybdenum specification this grade belongs to, covering the wider grade family.
Start here to confirm the family and the other grades.
The high-temperature carbon steel specification — same service, different material basis and no alloying.
Check whether your duty calls for carbon or alloy.
General-purpose carbon steel pipe. Widely available, and not intended for high-temperature service.
The specification ordinary carbon pipe usually refers to.
A worked example of how diameter, wall and schedule narrow an order before the grade is priced.
Relevant when dimensions are still being fixed.
Comparing across a standard family
A designation from one family is not an interchangeable part for a designation in another, and within the alloy family the grades are not tiers of one product either. Moving between them changes the alloy content, and with it the welding procedure, the treatment after welding and what the certificate has to demonstrate — so it has to be re-confirmed against your design basis rather than carried across from a grade name on an old requisition.
Where the requirement is a steel tube rather than a pipe, or the standard family is still open, check the product form first — the dimensional and standard basis changes with it, and so does what the certificate has to demonstrate.
Destination matters commercially on an alloy order — the UAE market page sets out how project coordination and release documents are handled locally, which is worth reading before you fix the delivery basis.
From stated basis to offer
The gate settles what the pipe has to suit. This is the sequence that turns it into a comparable offer, and the point at which each piece of evidence is actually tested.
Design basis stated
Design authority
The temperature, pressure and service the line runs at are on the enquiry.
Without them the grade choice cannot be judged.
Grade and edition confirmed
Buyer
A335 P11, in a named product form, against a stated edition of the specification.
An unstated grade or edition makes quotations incomparable.
Condition and tests agreed
Buyer and commercial desk
The delivered heat-treated condition and the test package the order carries are fixed.
A test or treatment not ordered cannot be produced afterwards.
Fabrication scope flagged
Buyer and fabricator
Where joints are involved, the welding and post-weld treatment stay in view.
A documentation gap shows up at the weld, not on the desk.
Technical review
Commercial desk
The stated basis is read back against the governing edition and the project requirement.
Conflicts surface here, before money is committed.
Offer with commercial terms
Commercial desk
Availability, price, quantity and delivery confirmed on request.
Commercial variables stay open until you supply them.
Send the completed gate and the desk comes back against your requirement rather than a standard package. Reachable Monday to Saturday, 8.00 AM to 6.00 PM Gulf time.
Request a QuoteStraight answers
These are the ones the desk fields most often from power and process buyers, answered the way they are answered there — including the parts that make the process slower.
Not as a sourcing convenience, no. They are separate grades within the same specification, chosen for their own design reasons, and moving between them changes the alloy content — which changes the welding procedure, the treatment after welding and what the certificate has to demonstrate. If a substitute grade is acceptable to your design, that is a decision for whoever owns the design basis, and it should be written onto the enquiry as the grade you now want. We will quote what your requirement states rather than quietly offering a different grade because it happens to be available.
The treatment of a welded joint follows from the governing design code, the grade, the wall thickness and the specific joint, and it is normally performed by the fabricator who makes the weld, against a procedure qualified for that work. What sits with us is the condition the pipe is supplied in and the documentation that travels with it, which the fabricator needs in order to plan the joint correctly. If your scope includes welded assemblies, say so on the enquiry and the fabrication basis can be discussed against the code you are working to — but we will not hand you a PWHT value as if it were a catalogue figure.
To the form and manufacturing route your specification states. Both exist for high-temperature pipe, and which one is right depends on the design code, the pressure and temperature duty, the diameter and wall, and your project's own rules. Substituting one for the other because it is easier to source would put a decision in our hands that belongs in your specification. If your requirement gives the dimensions but leaves the form open, the enquiry should say so, and we will come back with what is offered and how each option is documented.
We quote against the edition your project is written to, and it does matter. The grades covered, the testing provisions and the marking requirements move between editions, so two suppliers quoting 'A335 P11' against different editions are not necessarily offering the same deliverable. Naming the edition is what makes the prices you are comparing describe the same product. If you do not have it to hand, ask us to confirm the current one — but do not let it stay unstated and assume both offers meant the same thing.
It includes what your order and the governing edition call for, plus any supplementary testing your project specification adds — and the honest answer is that the package is defined by those documents, not by a default list we would put on a page. What we can commit to is that the testing written onto the order is the testing performed and evidenced, and that the results travel with the heat identity so they can be tied to your pipe. Review the test scope before the order rather than assuming a standard package covers it.
We do not publish stock positions on this page, because a figure written here would be stale by the time it mattered, and availability at this grade varies with diameter, wall, product form and testing requirement. It is confirmed against your stated basis, quantity and required date when the enquiry reaches the desk. That is the honest sequence: the answer you plan around is the one given for your order.
Frequently asked questions
Five questions high-temperature equipment buyers raise most often, answered without deferring the technical position to the quotation stage.
They belong to the same specification — A335 covers several chromium-molybdenum grades — but they are separate grades, not tiers of one product. Moving from P11 to P22 or P91 changes the alloy content and, with it, the design and fabrication basis: the welding procedure, the heat treatment that follows welding and the testing the order carries are all specific to the grade and the joint. We cover P11 and P22 and P91 on this site because buyers ask about the family together, but we do not treat any of them as an automatic substitute for another. If your design calls for a different grade, the requirement should say so, and the fabrication documents should be built for that grade from the start.
Whether a welded joint needs post-weld heat treatment is an engineering decision that belongs to the governing design code, the grade, the wall thickness and the specific joint — not something a supplier can settle by itself. What we can tell you is how the pipe is supplied to you — its heat-treated condition at delivery — and what documentation the order will carry. The PWHT of a fabrication is normally performed by the fabricator against their qualified procedure. If your scope includes welded assemblies, state it on the enquiry and the fabrication basis can be discussed against the code you are working to.
Both forms exist for high-temperature pipe, and which one your requirement needs depends on the design code, the pressure and temperature duty, the diameter and wall, and your project's own rules on the product form. We will quote to the form and manufacturing route your specification states rather than substituting a different one because it is easier to source. If your requirement states the diameter and wall but leaves the form open, say so on the enquiry and we will come back with what is offered and how each option is documented.
We quote against the edition your project is written to. Editions matter here because the grades covered, the testing provisions and the marking requirements move between them, which means two suppliers quoting 'A335 P11' against different editions are not necessarily offering the same thing. The edition is one of the inputs we ask for on the enquiry, and if it is not stated we will say so rather than assume the latest and leave the comparison to chance.
The chromium-molybdenum grades of A335 are ferritic steels. What matters in practice is not the pipe's magnetic behaviour as a curiosity but the one thing it drives: for a ferritic alloy joint the more common site technique is the magnetic particle examination of the root or the finished weld rather than the dye-penetrant method used more often on austenitic work. That is a joint inspection decision the fabricator makes against the governing design code and their own procedures. State the examination the order and the fabrication call for, and the test package is built to match.
Still settling the basis?
Send the enquiry with what you have stated and flag what is still open. The desk will tell you which inputs it needs before it can price, rather than returning a number built on assumptions.
Noor Deira Steel Trading L.L.C.
Office 3303, Churchill Executive Tower, Business Bay, Dubai, United Arab Emirates · Monday to Saturday, 8.00 AM to 6.00 PM, Sunday closed.
Request a quote
Complete the gate as far as your project allows and send it with your requirement. The commercial desk confirms availability, price and the testing and documentation scope from what you state — price on request.
What a P11 enquiry needs
The design temperature, pressure and service the line runs at
The grade confirmed as A335 P11
The governing edition of the specification
Outside diameter, wall thickness and length
The product form — seamless or welded — if your spec fixes it
The delivered heat-treated condition and required test package
The welding and PWHT scope, if the pipe will be fabricated
Quantity, delivery point and required date
Prefer to talk it through?
