Petroleum Cracking Seamless Tubing Definition:
Petroleum Cracking Seamless Tubing is a long, hollow, seamless steel that is an economical material for industry due to its efficient cross-sectional design. With its weldless, continuous structure, this tube excels in compressive strength and durability and is widely used in the manufacture of critical mechanical components such as drill pipes in oil drilling equipment, automotive driveline components, bicycle frames, and structural steel support frames at building construction sites.
Petroleum Cracking Seamless Pipe Standard:
I. China National Standard (GB/T9948)
i.Core Specification
a.Scope of Application: Specially designed for petroleum refining units, applicable to cracker pipe, heat exchanger pipe, reactor pipe and other high temperature and high pressure scenarios.
b.Material Requirements: Base material: carbon steel (20G), chrome-molybdenum alloy steel (15CrMoG, 12Cr2MoG, etc.), austenitic stainless steel (1Cr18Ni9).
c. Chemical composition: C, Si, Mn, Cr, Mo and other elements of the content of strict limits (such as 12Cr2MoG requires Cr content of 2.0-2.5%, Mo content of 0.9-1.1%).
ii.Mechanical properties:
a. High-temperature strength: 550 ℃ lasting strength needs to be ≥ 60MPa (12Cr2MoG as an example).
b. Impact toughness: -20℃ low-temperature impact work ≥34J.
c. Process requirements: must be hot-rolled or cold-drawn seamless process, prohibit the use of welded pipe. d. Need 100% eddy current test.
d. 100% eddy current flaw detection + 20% ultrasonic re-inspection is required.
II. Mainstream international export standards
i. American Standard
a. ASTM A335: Standard for seamless tubes of ferritic alloy steel for high temperature use, corresponding to the Chinese 12CrMo series.
b. Typical grades: P11 (1.25Cr-0.5Mo), P22 (2.25Cr-1Mo).
c. Key Differences: Hardness gradient test (HV10 test) is required.
d. ASTM A312: Standard for austenitic stainless steel seamless tubes for corrosive media environments.
ii. European Standards
a. EN 10216-2: Standard for seamless tubes and pipes for pressure purposes, covering materials such as P265GH, 15Mo3, etc. b. Special Requirements: Required to provide 3.0mm hardness test (HV10 test).
b. Special requirements: ultrasonic test report for defects below 3.2mm is required.
c. EN 10216-5: Special standard for seamless stainless steel tubes and pipes, requiring intergranular corrosion test (ISO 3651-2).
iii. Japanese Standards
a. JIS G3458: Standard for alloy steel tubes, STPA series (e.g. STPA23 corresponds to 12Cr1MoVG).
b. Characteristic tests: Sulfur Print Test (Sulfur Print Test) is mandatory.
III. Comparison of domestic and foreign standards (12Cr2MoG as an example)
| Parameter | GB/T 9948 | ASTM A335 P22 | EN 10216-2 |
|---|---|---|---|
| Applicable Temperature | ≤600°C | ≤593°C | ≤580°C |
| Yield Strength | ≥275 MPa | ≥310 MPa | ≥280 MPa |
| Hardness Requirement | ≤225 HBW | ≤250 HBW | ≤265 HBW |
| Impact Energy | ≥34 J (-20°C) | ≥41 J (21°C) | ≥40 J (0°C) |
Petroleum cracking seamless pipe manufacturing process details
I. Hot Rolled Seamless Tube Process
The Hot Rolled Seamless Tube Process is designed for the mass production of high-strength tubes and consists of 12 key processes:
i. Billet Processing: Heating the round billet to 1,200-1,280°C to optimize the material plasticity.
ii. Forming Processing: Formation of hollow billet by piercing machine and control of wall thickness tolerance ±5% by three-roll tilting technology.
iii. Dimensional Finishing: Upgrading of OD accuracy to ASTM A530 standard by sizing/reducing unit.
iv. Quality Verification: 100% eddy current flaw detection for surface defects, hydrostatic test pressure up to 30MPa.
v. Intelligent Marking: Laser engraved traceable code with steel grade, furnace number, and execution standard.
vi. Technical Advantage: The capacity of a single line can be up to 50 tons/hour, which is suitable for the production of large-diameter pipes above Φ114mm.
II. Cold Drawn Seamless Pipe Process
For the demand of high precision thin walled tubes, an 18-step precision control process is adopted:
i. Pre-treatment: Tube billet beheading treatment to form the haul-off end, annealing at 850°C to eliminate residual stress.
ii. Surface Engineering: Hydrochloric acid pickling to remove oxide skin, phosphate coating to reduce the friction coefficient of cold-drawing.
iii. Deformation Processing: Wall thickness tolerance of ±0.05mm is achieved through 8-12 passes of cold-drawing.
iv. Performance regulation: Protective atmosphere heat treatment ensures uniform hardness (HRC 22±2).
v. Non-destructive testing: Ultrasonic flaw detection identifies internal defects up to 0.3mm in depth.
vi. Core value: Production of Φ6-89mm precision tubes, surface roughness Ra≤1.6μm.
III. Comparison of key technologies
| Parameter | Hot Rolling Process | Cold Drawing Process |
|---|---|---|
| Production Efficiency | 45-60 tons/hour | 3-5 tons/hour |
| Dimensional Accuracy | ±0.5% | ±0.1% |
| Surface Finish | Oxide scale requires subsequent treatment | Mirror finish achieved directly |
| Applicable Scenarios | Main pipelines for energy transportation | Precision components for hydraulic systems |
| Energy Consumption per Unit | 280 kWh/ton | 420 kWh/ton |
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