P110 is a high-strength general-purpose oil casing steel grade, focusing on mechanical strength, with a yield strength of 758–965 MPa, suitable for deep well high-pressure environments, but it does not have sulfur resistance; while C110 is a sulfur-resistant steel grade specifically designed for sulfur-containing (H₂S) environments, with a narrower yield strength range (758–828 MPa), and its hardness is strictly controlled at ≤30 HRC to prevent sulfide stress corrosion cracking (SSC).
API 5CT P110 vs. C110 Casing and Tubing Mechanical Properties Comparison
| Parameter | P110 (Group 3) | C110 (Group 2) |
| Yield Strength | 110 - 140 ksi (758-965 MPa) | 110 - 120 ksi (758-827 MPa) |
| Tensile Strength | ≥ 125 ksi (≥ 862 MPa) | ≥ 115 ksi (≥ 793 MPa) |
| Yield-to-Tensile Ratio | No API mandatory limit | Strictly controlled (to ensure ductility) |
| Maximum Hardness | No API mandatory limit | ≤ 30.0 HRC (Critical control index) |
| Hardness Variation | No special requirements | Extremely strict (minimal fluctuation per joint/batch) |
| Impact Test | Calculated per API formulas | Mandatory; usually requires higher absorbed energy |
API 5CT P110 vs. C110 OCTG Chemical Composition Comparison
| Element | P110 | C110 |
| Carbon (C) | No API limit (typically 0.25-0.35%) | Strictly controlled (typically 0.22-0.35%) |
| Manganese (Mn) | No API limit | Strictly controlled (prevents segregation-induced cracking) |
| Chromium (Cr) | No API limit | Mandatory (typically 0.5-1.5% for tempering resistance) |
| Molybdenum (Mo) | No API limit | Mandatory (typically 0.4-1.0% to enhance SSC resistance) |
| Sulfur (S) / Phosphorus (P) | ≤ 0.010 / ≤ 0.020 (for PSL-2) | ≤ 0.005 / ≤ 0.015 (Ultra-low requirement) |
| Other Alloys | Optional | Usually contains V, Ti, B, etc., for grain refinement |
API 5CT P110 vs. C110 oil casing Testing & Quality Control (QC) Comparison
| Test Item | P110 | C110 |
| SSC (Sulfide Stress Cracking) | Not Required | Mandatory (NACE TM0177 Method A/B/D) |
| Hardness Testing | Random sampling (per API frequency) | Piece-by-piece / End-to-end multi-point testing |
| Grain Size | No special requirements | Must be fine-grained (typically ASTM 7 or finer) |
| Heat Treatment | Full-body Quench & Temper (Q&T) | More precise, longer duration full-body Q&T |
| NDE (Non-Destructive Evaluation) | Standard API requirements | Higher level Ultrasonic / Magnetic Flux Leakage testing |
API 5CT P110 vs. C110 oil well casing Application, Appearance, and Economics Comparison
| Item | P110 | C110 |
| Applicable Environment | Sweet Service: Deep, high-pressure wells | Sour Service: Deep, high-pressure acidic wells |
| Primary Failure Risk | Insufficient strength or fatigue failure | SSC (Sulfide Stress Cracking) brittle failure |
| Color Banding | One White Band | One White + Two Brown Bands |
| Procurement Cycle | Usually in stock; short lead time | Typically custom production; long lead time |
| Price Index | 1.0 (Baseline) | 2.5 - 3.5 (Extremely premium/expensive) |
API 5CT P110 / C110 Common Tubing Dimension Table
| Nominal OD (in) | OD (mm) | Weight (lb/ft) | Wall Thickness (mm) | Drift Diameter (mm) | Remarks / Application |
| 2-3/8" | 60.33 | 4.70 | 4.83 | 48.36 | Standard deep-well tubing. |
| 2-7/8" | 73.03 | 6.50 | 5.51 | 60.33 | Most common high-pressure tubing spec. |
| 3-1/2" | 88.90 | 9.30 | 6.45 | 75.13 | High-production / High-pressure gas wells. |
| 4-1/2" | 114.30 | 12.75 | 6.88 | 98.22 | Large-bore production / Completion strings. |
| 4-1/2" | 114.30 | 13.50 | 7.37 | 96.39 | Heavy-wall for extremely high external pressure. |
API 5CT P110 / C110 Common Casing Dimension Table
| Nominal OD (in) | OD (mm) | Weight (lb/ft) | Wall Thickness (mm) | Drift Diameter (in/mm) | Typical Application |
| 4-1/2" | 114.30 | 11.60 | 6.35 | 3.875" (98.43) | Production casing / Liner. |
| 4-1/2" | 114.30 | 13.50 | 7.37 | 3.795" (96.39) | High-pressure zone completion. |
| 5-1/2" | 139.70 | 17.00 | 7.72 | 4.767" (121.08) | Mainstream for Shale Oil/Gas & Deep Gas wells. |
| 5-1/2" | 139.70 | 20.00 | 9.17 | 4.653" (118.19) | For extreme high-collapse requirements. |
| 7" | 177.80 | 26.00 | 9.19 | 6.151" (156.24) | Deep-well production casing. |
| 7" | 177.80 | 29.00 | 10.36 | 6.059" (153.90) | Isolation of high-pressure formations. |
| 7" | 177.80 | 32.00 | 11.51 | 5.969" (151.61) | Critical sections in ultra-deep wells. |
| 9-5/8" | 244.48 | 40.00 | 10.03 | 8.679" (220.45) | Intermediate casing (common for P110). |
| 9-5/8" | 244.48 | 47.00 | 11.99 | 8.525" (216.54) | Heavy-weight intermediate casing for deep wells. |
| 9-5/8" | 244.48 | 53.50 | 13.84 | 8.379" (212.83) | To handle ultra-high external (collapse) pressure. |
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FAQ
What is API P110 material specification?
API 5CT P110 is an API 5CT high-grade casing and tubing made by seamless and EW welding process with a minimum yield strength of 758 MPa and a minimum tensile strength of 862 MPa. Commonly used in high-pressure environments in deep wells.
API 5CT P110 is a premium seamless steel grade used for casing in deep-well drilling. With higher yield and tensile strength than J55 or N80, it withstands extreme pressures and temperatures. Its superior toughness and stability reduce the risk of damage, making it a preferred choice for high-end, reliable oil and gas production.
