API 510 WPS and PQR review: BOK scope and a step-by-step method

What the Body of Knowledge scopes

The Body of Knowledge for September 2026, January 2027 and May 2027 (it replaces the September 2025 version) sets out Section II on page 5. In our words, it expects you to be able to:

• decide whether the WPS, PQR and WPQ comply with Section IX and with any extra requirements in API 510
• decide whether every required essential and nonessential variable has been addressed
• decide whether the number and type of mechanical tests on the PQR are the right ones, and whether the results are acceptable
• decide whether the welder is qualified to make a production weld to the WPS

The same page fences the review in:

BOK limit (page 5)	What it means for your practice
Processes: SMAW, GTAW, GMAW or SAW only	Drill the variable tables for those four processes
One process per WPS, PQR or WPQ	No combination procedures to untangle
Each WPS is supported by a single PQR	Every WPS line traces back to one record
One filler metal per process	One filler column on each form
The WPQ coupon is welded to a qualified WPS	The WPQ check starts from the WPS
Base metals: P-No. 1, 3, 4, 5 and 8	Know which materials those P-Nos. cover
Dissimilar base metals and dissimilar thicknesses excluded	Both sides of the joint match
Overlay, hard-facing and buttered dissimilar welds excluded	Groove and fillet procedures only
For P-No. 1, 3, 4 and 5: lower transition 1330°F (720°C), upper transformation 1600°F (870°C)	Use these figures for any PWHT comparison
Supplementary essential variables are not part of the WPS/PQR	Note them, but the review doesn't turn on them

Two more points from the same page shape a review. Editorial items such as the WPS revision level, company name, WPS number and date and the testing lab's name are excluded. But the BOK says API 510 candidates must know that the PQR and WPQ must be certified by signing and dating. It also says any welding rule in API 510 takes precedence over Section VIII, Division 1 on the same subject, and that you should know all of API RP 577. Brazing is not covered.

The effectivity sheet for the same windows lists the 2025 edition of the ASME code, with Section IX marked "welding only", and API RP 577, 3rd edition (October 2020) with Errata 1 (September 2025).

Where things sit in Section IX

ASME's outline for its Section IX course) gives the layout of the welding part (Part QW) by article:

• Article I: welding general requirements
• Article II: welding procedure qualifications
• Article III: welding performance qualifications (the WPQ side)
• Article IV: welding data, where the variables themselves are defined
• Article V: standard welding procedure specifications

The same outline names Table QW-253 as the table of WPS qualification variables for SMAW. The outline names only that one. For a GTAW, GMAW or SAW procedure, find the matching variable table in your own copy before you start.

ASME's suggested forms show how the records are organized. The WPS form, QW-482, points to QW-200.1, and the PQR form, QW-483, points to QW-200.2. The PQR form is headed as a record of the actual variables used to weld the test coupon, which is the key contrast: a WPS gives ranges, and a PQR gives what actually happened.

Both forms group their entries under the same Article IV paragraphs:

Paragraph	Variable group	On the WPS (QW-482)	On the PQR (QW-483)
QW-402	Joints	Joint design, root spacing, backing	Groove design of the test coupon
QW-403	Base metals	P-No. and group, thickness range	P-No. and group, coupon thickness and diameter
QW-404	Filler metals	SFA spec, AWS class, F-No., A-No., deposit range	The same items, as used
QW-405	Positions	Groove and fillet positions, progression	Position and progression used
QW-406	Preheat	Minimum preheat, maximum interpass	Preheat and interpass recorded
QW-407	PWHT	Temperature and time ranges	Temperature and time used
QW-408	Gas	Shielding, trailing and backing gas	The same items, as used
QW-409	Electrical characteristics	Current, polarity, amp and volt ranges per pass	Current, polarity, amps, volts, heat input
QW-410	Technique	String or weave, cleaning, single or multiple pass	Travel speed, string or weave, passes

The back of the PQR form carries the test results: tensile tests (QW-150), guided-bend tests (QW-160), toughness tests (QW-170) and the fillet-weld test (QW-180). The PQR form ends with a certification line, with an organization, a date and a "certified by" signature.

A note on the forms' dates. The PDFs ASME posts carry revision marks of 07/13 on both PQR pages and the WPS front, and 07/10 on the WPS back. The effectivity sheet calls for the 2025 edition. We have not checked the forms against the 2025 printing, so use the table above as a map and confirm each paragraph number in your own copy.

A step order for reviewing a WPS against its PQR

This order follows the BOK's four tasks and the layout of the two forms. It is our own method, not one API or ASME publishes.

1. Confirm the review is in scope. One process from the four, base metals from the five P-Nos., no dissimilar joints, no overlay.
2. Link the two documents. The WPS names its supporting PQR, and the PQR names the WPS it was run for. They should point at each other.
3. Check the PQR is certified. Signed and dated, as the BOK requires. An unsigned PQR is a finding before any variable is compared.
4. Open the variable table for the process. For SMAW that is Table QW-253. Keep it open for the next two steps.
5. Work through QW-402 to QW-410 in order. For each line on the table, put the WPS value or range next to the PQR's recorded value. Mark each one as covered by the PQR, changed but nonessential, or changed and essential.
6. Check that nothing required is missing. The BOK's second task is that every required essential and nonessential variable is addressed. A blank where the table lists a variable counts as a finding, the same as a wrong value.
7. Check the tests. The type and number of specimens on the back of the PQR against what Section IX requires for that coupon, then each result against the acceptance rule in the test paragraph the form names (QW-150 to QW-180).
8. Redo the arithmetic. Width times thickness gives the area, and the load divided by the area gives the unit stress. The form gives you every number you need to check the lab's working.
9. Apply API 510's welding rules. Where API 510 says something about the same subject, it takes precedence over Section VIII, Division 1.
10. Then the welder. Take the WPQ against the WPS and Article III to answer the BOK's fourth task.

Worked review (invented documents)

Needs credential-holder sign-off. Every value below is invented for practice. This is not an exam item, it reproduces no code text, and a credential holder has not yet reviewed it. Where a finding depends on what Section IX says, we name the paragraph to open and leave the decision to your copy.

The documents. WPS LS-07 (SMAW, manual) lists PQR LS-07P as its support. PQR LS-07P lists WPS LS-07.

Group	WPS LS-07 says	PQR LS-07P records
QW-402 Joints	Single-V groove, 60° included angle, backing optional	Single-V groove, 60°, no backing
QW-403 Base metals	P-No. 1 to P-No. 1, 3/16 in. to 1-1/2 in.	P-No. 1 to P-No. 1, coupon 3/4 in. plate
QW-404 Filler metals	SFA 5.1, E7018, F-No. 4, A-No. 1, 1/8 and 5/32 in.	SFA 5.1, E7018, F-No. 4, A-No. 1, 1/8 in.
QW-405 Positions	All, vertical uphill	3G, uphill
QW-406 Preheat	50°F min, 500°F max interpass	60°F preheat, 450°F interpass
QW-407 PWHT	1100°F to 1400°F, 1 hr per in.	1150°F, 1 hr
QW-409 Electrical	DCEP, 90 to 160 A, 20 to 26 V	DCEP, 120 to 135 A, 22 to 24 V
QW-410 Technique	String or weave, multipass	String, multipass, 5 in./min travel
Tensile (QW-150)		2 specimens (below)
Bends (QW-160)		4 side bends, each recorded as acceptable
Toughness (QW-170)		None
Certification		Organization and date filled in, "certified by" blank

The F-No. and A-No. pairs are the invented forms' entries. Confirm the assignments for any real filler in your own copy.

Tensile results as the PQR records them, with a specified minimum tensile strength of 70,000 psi for the base metal written on the record (invented):

Specimen	Width (in.)	Thickness (in.)	Area (in.²)	Load (lb)	Unit stress recorded (psi)	Break
T-1	0.750	0.745	0.5588	40,600	72,660	Base metal
T-2	0.751	0.742	0.5572	38,100	73,800	Weld metal

Step 1, scope. SMAW, P-No. 1 to P-No. 1, same thickness on both sides, a groove weld. In scope.

Step 2, link. Each document names the other. Fine.

Step 3, certification. Finding. The "certified by" line is blank. The BOK says the PQR must be signed and dated, so this PQR can't support the WPS as it stands.

Steps 4 to 6, variables. With Table QW-253 open:

• QW-403 thickness. The coupon is 3/4 in. and the WPS claims 3/16 in. to 1-1/2 in. Check both ends of that range against the thickness rules your edition points to for SMAW.
• QW-404 filler. SFA spec, class, F-No. and A-No. match. The WPS adds a 5/32 in. electrode the PQR didn't use. Find how the table classes electrode size before you call it a finding.
• QW-405 positions. The PQR was welded in 3G uphill, and the WPS claims all positions uphill. Find whether position is a procedure essential variable on the table.
• QW-406 preheat. The WPS minimum of 50°F is 10°F below the 60°F on the PQR. Find the preheat line on the table and how large a decrease it permits.
• QW-407 PWHT. Flag for a decision. The PQR coupon was heat treated at 1150°F, below the BOK's 1330°F lower transition temperature for P-No. 1. The WPS range runs to 1400°F, above it. Our reading (inferred) is that the BOK gives that figure for comparisons like this one. Open QW-407 and the table's PWHT lines to decide whether a range that crosses 1330°F is supported by a coupon treated below it.
• QW-409 and QW-410. The WPS ranges contain the PQR's recorded values. Find which of these lines the table lists as nonessential for SMAW, and for each one, check the WPS addresses it.
• Supplementary essentials. No toughness tests on the PQR. Under the BOK, supplementary essential variables are not part of this review, so note it and move on.

Steps 7 and 8, tests and arithmetic. Finding. Redo each tensile row:

• T-1: 0.750 × 0.745 = 0.5588 in². 40,600 ÷ 0.5588 = about 72,660 psi. Matches the record.
• T-2: 0.751 × 0.742 = 0.5572 in². 38,100 ÷ 0.5572 = about 68,370 psi, not the 73,800 psi recorded.

The corrected T-2 figure is below the 70,000 psi written on the record, and the specimen broke in the weld metal. Open QW-150 for the tension test acceptance rule, including what it says about where a specimen breaks, to decide whether T-2 passes. Then check that two tensile specimens and four side bends are the right type and number for a 3/4 in. coupon.

Step 9, API 510. Nothing on these documents touches an API 510 welding rule. On a repair WPS you would check that next.

Summary of the invented review.

Item	Status
Blank certification on the PQR	Finding, from the BOK itself
T-2 unit stress miscalculated on the record	Finding, from the arithmetic
T-2 corrected stress against the acceptance rule	Decide in QW-150
PWHT range crossing 1330°F	Decide in QW-407 and Table QW-253
Preheat decrease, extra electrode size, all positions, thickness range	Classify each one in Table QW-253

The method is the point. Two findings came straight from the documents, without opening the code. The rest come down to one table and a few paragraphs, and finding them fast in your own copy is what the open-book part rewards.

How to practice this

• Write your own WPS and PQR pairs with invented values, plant one or two errors in each, swap with a study partner and review each other's using the ten steps.
• Practice the lookups one PDF at a time with no Find function, the way our open-book guide describes.
• Keep the scope facts on page 5 of the BOK on recall cards: the four processes, the five P-Nos., the two temperatures and the signing rule. Our closed-book guide shows how to turn BOK lines into prompts.
• Read Section II alongside the other four in our Body of Knowledge guide.
• Take the free 10-question check to see whether welding review or another BOK section should come first. Its questions are original and aren't drawn from the exam.

Sources

Show the list

• API 510 Body of Knowledge, September 2026, January 2027 and May 2027, American Petroleum Institute, pages 1 and 5. Retrieved 21 Oct 2026.
• API 510 Exam Publications Effectivity Sheet, September 2026, January 2027 and May 2027, American Petroleum Institute. Retrieved 21 Oct 2026.
• API 510 Pressure Vessel Inspector: exam information, American Petroleum Institute. Links the BOK and effectivity sheet for the current windows. Retrieved 21 Oct 2026.
• Form QW-482, suggested format for WPS, ASME, marked 07/13 (front) and 07/10 (back). Retrieved 21 Oct 2026.
• Form QW-483, suggested format for PQR, ASME, marked 07/13. Retrieved 21 Oct 2026.
• ASME BPV Code Section IX course outline), ASME. Article layout of Part QW and the Table QW-253 module. Retrieved 21 Oct 2026.