API 5CT P110 Deep Well Casing
API 5CT P110 is a high-strength steel grade used primarily for casing in oil and gas wells. It is categorized under the "High Strength" group of the API 5CT specification.
Naming Convention: The "P" represents the steel grade, and "110" refers to the minimum yield strength of 110,000 psi.
Applications: It is specifically designed for deep wells, ultra-deep wells, and high-pressure environments where the casing string must support its own massive weight and withstand high internal burst pressures.
Note: While P110 has high tensile strength, it is generally more sensitive to Sulfide Stress Cracking (SSC). Therefore, caution is required when using standard P110 in high-concentration H2S (sour) environments.
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API 5CT P110 Deep Well Casing Overview
API 5CT P110 is the Group 3 high-strength casing grade for ultra-deep wells and HPHT completions. Quenched and tempered to a yield range of 110,000-140,000 psi (758-965 MPa), it carries the self-weight of long casing strings and high burst loads that exceed the capability of N80 casing. GNEE supplies P110 casing with API 5CT monogrammed mill certification in PSL1 and PSL2.
Standard: API Spec 5CT / ISO 11960, Group 3, Q&T mandatory, PSL1 and PSL2
Strength: yield 110,000-140,000 psi (758-965 MPa), min tensile 125,000 psi (862 MPa)
Sizes: OD 4-1/2" to 20", weights 9.5-133 lb/ft, R1/R2/R3 lengths
Connections: LTC and BTC preferred; STC rarely specified; premium connections on request
Color code: one white band, coupling painted white
Service: sweet wells deeper than 4,500 m; NOT for sour service (use C110 or T95)
Editor's note: to clarify two figures on this page: API 5CT sets the minimum tensile strength of P110 at 125,000 psi (862 MPa) - 965 MPa is the maximum yield, not the minimum tensile. And because API 5CT leaves Group 3 chemistry to the manufacturer, the C range 0.25-0.35% in the table below and the 0.34-0.43% figure cited in the inspection list are both typical mill control ranges, not standard-mandated values; only P and S are capped by the standard (PSL1: 0.030%/0.030%; PSL2: 0.020%/0.010%).
API 5CT P110 Color Code Table
Color coding is used for quick visual identification at the well site.
| Steel Grade | Color Band (on Pipe) | Coupling Color |
| P110 | One White Band | Entire coupling painted White |
API 5CT P110 Chemical Composition Table
API 5CT sets limits primarily on harmful elements (P and S). The specific alloying elements (C, Mn, Cr, Mo) are determined by the manufacturer to reach mechanical requirements.
| Element | Content (Percentage %) |
| Carbon (C) | Manufacturer defined (typically 0.25 - 0.35%) |
| Manganese (Mn) | Manufacturer defined (typically 1.20 - 1.50%) |
| Phosphorus (P) | ≤ 0.030% |
| Sulfur (S) | ≤ 0.030% |
| Silicon (Si) | ≤ 0.45% |
| Cr / Mo | Often added to improve hardenability |
API 5CT P110 Mechanical Property Table
| Property | Units (Imperial/Metric) | Value |
| Yield Strength | psi (MPa) | 110,000 - 140,000 (758 - 965) |
| Tensile Strength | psi (MPa) | ≥ 125,000 (862) |
| Hardness (Reference) | HRC | 28 - 32 (typical) |
| Elongation | % | Calculated based on specimen area (usually ≥ 15%) |
API 5CT P110 Size Chart (Common Sizes)
| Outer Diameter (OD) - inch | OD - mm | Wall Thickness Range (mm) | Weight Range (lb/ft) |
| 4-1/2" | 114.3 | 5.21 - 15.11 | 9.5 - 21.5 |
| 5-1/2" | 139.7 | 6.22 - 14.27 | 14.0 - 26.0 |
| 7" | 177.8 | 6.91 - 15.11 | 20.0 - 38.0 |
| 9-5/8" | 244.5 | 7.92 - 15.11 | 36.0 - 53.5 |
| 13-3/8" | 339.7 | 9.65 - 15.11 | 48.0 - 72.0 |
API 5CT P110 Dimensional Tolerance Table
| Item | Tolerance |
| Outside Diameter (OD) | Under 4": ±0.031"; 4" & Above: +1.00% / -0.50% |
| Wall Thickness | -12.5% (Positive tolerance limited by weight) |
| Weight | Single Joint: +6.5% / -3.5% |
| Length | R1: 4.88-7.62m; R2: 7.62-10.36m; R3: >10.36m |
| Straightness | Total deviation not to exceed 0.2% of length |
P110 vs Q125 vs C110 vs N80 Selection Guide
| Item | N80 | L80-1 | P110 | Q125 | C110 |
|---|---|---|---|---|---|
| API group | Group 1 | Group 2 | Group 3 | Group 4 | Group 2 |
| Yield, psi | 80,000-110,000 | 80,000-95,000 | 110,000-140,000 | 125,000-150,000 | 110,000-120,000 |
| Min tensile, psi | 100,000 | 95,000 | 125,000 | 135,000 | 120,000 |
| Max hardness | None | 23 HRC | None | None | 27 HRC |
| Sour service (H2S) | No | Yes | No | No | Yes |
| Heat treatment | N (N80-1) / Q&T (N80Q) | Q&T | Q&T | Q&T | Q&T |
| Typical depth | 3,000-4,500 m | Sour wells | 4,500-7,000 m | Deepest, HPHT | Sour, high strength |
| Relative cost | Medium | Higher | High | Highest | Highest |
For sour service selection details see our L80 vs P110 material selection guide and C110 sour service casing page.
Connections, PSL Level and Order Options
| Option | Available | Notes |
|---|---|---|
| STC (short round thread) | On request | Rarely specified for P110 - thread strength caps the string |
| LTC (long round thread) | Yes | Standard choice for 7" and larger deep well strings |
| BTC (buttress thread) | Yes | Highest API thread strength, preferred for 9-5/8" and larger |
| Premium connection | Machined on request | VAM / TenarisHydril type equivalents for HPHT gas wells |
| PSL1 / PSL2 | Both | PSL2 tightens P and S, adds mandatory CVN impact and NDT |
| Length range | R1 / R2 / R3 | R3 for deep wells reduces connection count per string |
API 5CT P110 Deep Well Casing Price
Indicative FOB China prices, November 2026. Firm quotation depends on size, wall, connection, PSL level and quantity.
| Item | Indicative FOB price, USD/ton |
|---|---|
| Plain end P110 casing, common sizes | 1,100 - 1,350 |
| Threaded and coupled (LTC / BTC) | 1,200 - 1,500 |
| PSL2 (adds CVN impact and NDT) | + USD 60 - 130 per ton |
| Premium connection machining | By connection type and size |
MOQ: 5 tons for stock sizes; 20 tons for production orders.
Delivery Time
| Order type | Lead time |
|---|---|
| Stock 5-1/2" and 7" sizes | 7 - 15 days |
| Production order (20 - 200 tons) | 25 - 40 days |
| R3 lengths / premium connections | 35 - 50 days |
P110 in Deep Well Casing String Design
In a typical ultra-deep completion, engineers run a tapered casing string: surface and intermediate sections in K55 or N80-1, transitioning to P110 for the production section where combined tensile (string self-weight) and burst loads peak. Two design points drive P110 specification:
Collapse in high-pressure formations: thick-wall P110 (for example 7" 35 lb/ft) resists the external pressure of overburden and narrow mud-weight windows at 5,000 m+
Burst during well control: the 140 ksi yield ceiling gives the burst margin needed for kick tolerance in HPHT zones
Temperature derating: above roughly 135 C, yield derating applies - confirm rating tables with the connection supplier
Sour risk check: if H2S partial pressure exceeds the NACE MR0175 window, switch that section to C110 or T95 instead of derating P110
inspection of P110 casing
The primary reference standard for the inspection of P110 casing is API SPEC 5CT, which stipulates requirements regarding chemical composition, mechanical properties, dimensional tolerances, and non-destructive testing for casing pipes.
According to the 11th Edition of API SPEC 5CT (published in December 2023), Grade P110 steel must satisfy the following key inspection criteria:
- Chemical Composition: Carbon content 0.34–0.43%, Molybdenum content 0.15–0.25%, and Phosphorus and Sulfur contents both ≤ 0.030%.
- Mechanical Properties: Minimum yield strength of 758 MPa (110 ksi), tensile strength ≥ 965 MPa, and elongation of 18–32%.
- Hardness Control: Brinell hardness (HB) must comply with standard limits to prevent brittle fracture.
- Non-Destructive Testing (NDT): Includes ultrasonic testing, magnetic particle inspection, etc., to ensure the absence of defects such as cracks or folds.
- Pressure and Seal Testing: Must pass hydrostatic testing to verify pressure-bearing capacity.
- Collapse Resistance: For deep-well applications, full-scale collapse resistance testing is required to evaluate stability under complex stress conditions.
Packing and Shipping
P110 deep well casing ships with thread protectors on both ends, bundled with steel strapping or crated for small OD. Every bundle carries export marks matching the heat numbers on the MTR for full traceability from mill to rig site. Couplings ship loose or made-up per order, casing shoes and float equipment can be included, and 20" sizes move by break-bulk vessel.
How to Order API 5CT P110 Deep Well Casing
Send your enquiry with size (OD x weight per foot), connection, PSL level, length range (R1/R2/R3), well depth and destination port - our OCTG engineers reply with a firm quotation and collapse/burst ratings within 24 hours.
API 5CT P110 OCTG Factory
API 5CT P110 Oil Well Casing test equipments
FAQ
What is the yield strength of P110?
Steel Grade P110 has a yield strength of 758 MPa (approximately 110 ksi)-its specified minimum yield strength-and is widely utilized in oil casing applications requiring high strength.
Is P110 carbon steel?
Yes, P110 is carbon steel; more precisely, it is a high-strength low-alloy (HSLA) carbon steel, primarily used for casing and tubing in the oil and gas industry.
When should I choose P110 instead of N80 or L80 casing?
Choose P110 when the casing string must carry heavy self-weight and high burst pressure in wells deeper than about 4,500 m, or in HPHT completions where N80 (max 110 ksi yield) and L80 (max 95 ksi) no longer provide sufficient safety margin. Note that P110 is not qualified for sour service - if H2S is present, step down to C110 or T95 for those sections.
What is the difference between P110 and Q125 casing?
Q125 is the strongest standard API grade: yield 125,000-150,000 psi (862-1,034 MPa) versus P110's 110,000-140,000 psi (758-965 MPa), with a minimum tensile of 135,000 psi versus 125,000 psi. Q125 serves the deepest and highest pressure strings (Group 4), while P110 covers most ultra-deep well requirements at lower cost. Both are Q&T grades with mandatory CVN impact testing.
What sizes, weights and connections are available for P110 deep well casing?
OD from 4-1/2 inch to 20 inch, weights from 9.5 to 133 lb/ft, in R1 (4.88-7.62 m), R2 (7.62-10.36 m) and R3 (over 10.36 m) lengths. Deep well strings most commonly use 5-1/2 inch, 7 inch and 9-5/8 inch in LTC or BTC connections; STC is rarely specified for P110 because thread strength limits the string. Premium connections are machined on request.
What is the difference between P110 and C110 casing?
Same yield strength class (110 ksi), but C110 is a Group 2 sour-service grade with strict hardness control (max 27 HRC), restricted chemistry and mandatory SSC testing per NACE MR0175. P110 is a Group 3 sweet-service grade with no hardness ceiling and significantly lower cost. Never substitute P110 for C110 in a well with H2S.
How much does API 5CT P110 deep well casing cost?
Indicative FOB China price is about USD 1,100-1,500 per ton depending on size, wall thickness, connection and PSL level, November 2026 market. Threaded and coupled LTC/BTC orders run USD 50-150 per ton above plain end, and PSL2 adds CVN impact and NDT costs. Email pipes@gneetube.com for today's firm quotation.
What is the delivery time for P110 casing?
Stock 5-1/2 and 7 inch sizes ship in 7-15 days. Production orders of 20-200 tons take 25-40 days because the quench-and-temper cycle and CVN testing add process time; R3 lengths or premium connections take 35-50 days.
Why is P110 more sensitive to sulfide stress cracking than lower grades?
P110's high strength comes from a quenched-and-tempered martensitic structure with no hardness ceiling under API 5CT. Hard microstructures above roughly 22-25 HRC are susceptible to sulfide stress cracking in wet H2S environments per NACE MR0175 / ISO 15156. This is why sour wells restrict P110 or require special SSC-resistant variants qualified by project testing.
How is API 5CT P110 casing packed for export?
Each joint receives thread protectors on both ends, pipes are bundled with steel strapping or crated for small OD, and every bundle carries export marks matching the heat numbers on the MTR. Couplings ship loose or made-up, and casing shoes, float collars and pup joints can be loaded in the same container.
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