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For OCTG (Oil Country Tubular Goods) manufacturing & pipe repair yards, three core machines define the quality and throughput of the whole workshop: bucking unit (makeup & breakout machine), pipe straightener, and hydrostatic testing machine. Improper layout will trigger frequent pipe collision, long material transit distance, low automation continuity, thread galling risk, and disqualified hydrostatic test batches.

With 30 years of OCTG equipment R&D experience, Huludao Boyu Petroleum Machinery (Boyu Petro) delivers integrated line matching solutions, combining YNJX planetary, YNJG wedge roller, YNJQ full rotational bucking units, multi-roll straighteners and full-automatic hydrostatic testers. This layout guide breaks down standard process sequences, two mainstream workshop layout schemes, equipment model matching rules, and intelligent linkage design, helping factories save floor space, boost production efficiency and fully comply with API & ISO quality trace standards.

1. Core Process Logic: Why This Trio Must Be Closely Matched

Before layout design, we need to clarify the sequential correlation of straightening, makeup and hydrostatic test in full OCTG production & repair lines:

Standard New OCTG Production Process

Raw pipe → End facing & beveling → Thread machining → Straightener (correct bending after threading) → Pre-tightening → Bucking Unit (torque-turn controlled coupling makeup) → Thread inspection → Hydrostatic Tester (full-length pressure sealing test) → Marking & packaging

OCTG Repair Line Process

Recycled pipe cleaning → Drift inspection → Straightener (fix deformation from downhole service → Thread repair → Bucking Unit breakout old coupling & re-makeup → Hydrostatic Tester re-qualification test

Critical Risks Caused by Disordered Layout

1)Straightener placed after bucking: Bent pipe leads to eccentric clamping on bucking unit, abnormal torque-turn curve, thread galling and metal seal failure.

2)Hydrostatic tester far from bucking: Long pipe transfer may scratch new threaded joints, resulting in hydrostatic leakage rejection.

3)Independent separated stations: Extra manual transfer reduces line automation rate and raises labor cost.

Boyu’s three-core equipment set supports seamless roller conveying linkage, eliminating intermediate manual handling and guarantee consistent thread sealing & pressure test pass rate.

2. Boyu Three Core Equipment Technical Positioning

2.1 Bucking Unit (Core Thread Assembly Station)

Three series cover all pipe & tool scenarios:

• YNJG Wedge Roller Bucking Unit: High-speed mass production for standard API tubing/casing; ideal for large-volume production lines matched with high-flow hydrostatic testers

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• YNJX Planetary Clamping Bucking Unit: High-precision grip for premium thread, small-medium CRA pipes; matched with compact single/double hydrostatic testers for premium pipe workshops.

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YNJQ Full Rotational Bucking Unit: Top-opening full circle rotation for large casing & downhole tools (2-3/8'' ~23''); paired with heavy-duty multi-station hydrostatic testers for big-bore tubular projects.

All models integrate torque-turn curve real-time monitoring, data storage and alarm linkage with hydrostatic tester system.

2.2 Multi-Roll Pipe Straightener

Boyu 7-roll / 9-roll hydraulic straightener corrects pipe straightness within 0.5mm/m, eliminating pipe bending after thread cutting. Equipped with automatic feeding roller tables directly connected to bucking unit inlet, realizing zero waiting pipe supply.

2.3 Automatic Hydrostatic Testing Machine

Single / double / quadruple station hydro testers support full-length high-pressure sealing test, automatic water filling, pressure holding & drainage. Test data synchronizes with bucking unit torque-turn report for one-file full pipe traceability, meeting FAT factory acceptance requirements.

3. Two Mature Workshop Layout Schemes from Boyu Engineering Team

Scheme 1: Linear Straight-Line Layout (For New Large-Scale OCTG Factories)

Applicable Workshop Condition

Workshop length ≥60m, annual output ≥50,000 tons, mass production of standard API tubing & casing, matching YNJG series high-speed bucking unit + 9-roll straightener + quadruple hydrostatic tester.

Station Arrangement Sequence (Front to Back)

Raw pipe feeding roller → End machining → Straightener station → Buffer roller table → Bucking unit station (with CNC torque-turn HMI) → Thread inspection platform → Hydrostatic tester multi-station → Finished pipe output rack

Layout Advantages

1.One-way straight pipe conveying without cross traffic, completely avoid pipe collision scratch;

2.Unified central electrical control cabinet for three machines, synchronous parameter calling;

3.Easy to expand more bucking/hydrostatic stations in later production capacity upgrade;

4.Floor space utilization rate up to 89%, convenient overhead crane pipe handling.

Boyu Matching Case

Saudi Arabia OCTG factory whole line: YNJG570 bucking unit + 9-roll straightener + 4-station hydro tester linear layout, daily output 220 pcs casing, torque & pressure test pass rate 99.8%.

Scheme 2: U-Type Compact Loop Layout (For Pipe Repair Yard / Small Premium Pipe Workshop)

Applicable Workshop Condition

Workshop area below 2,000㎡, small batch premium thread & recycled pipe repair, matching YNJX planetary bucking unit + 7-roll straightener + double-station hydrostatic tester.

Station Arrangement Sequence

Raw material feeding area → Straightener (short conveying roller) → Bucking unit central station → Hydrostatic tester arranged vertically beside bucking → Finished pipe storage loop back to unloading zone

Layout Advantages

1.Short pipe transfer distance, save 30% workshop floor area;

2.Single operator can monitor straightener, bucking HMI and hydrostatic touch screen simultaneously;

3.Low transformation cost for old workshops, no need large civil reconstruction;

4.Ideal for small batch multi-spec premium pipe flexible production.

Boyu Matching Case

Oman premium downhole tool project: YNJQ590 full rotational bucking unit + straightener + heavy hydrostatic tester U-layout, realize 2-23'' full range pipe assembly & pressure test in limited plant space.

4 Equipment Model Matching & Supporting Auxiliary Configuration Rules

4.1 Diameter & Torque Matching Table

4.2 Unified Auxiliary Conveying System (Boyu Standard Supporting)

1.Automatic roller tables between three stations, pneumatic pipe shift device, no manual hoisting;

2.Central hydraulic station shared design (optional) to reduce pipeline duplication and power consumption;

3.Unified CNC control system: torque-turn curve, straightness data, hydrostatic pressure curve stored in one database for batch traceability;

4.Safety linkage: emergency stop signal synchronized among straightener, bucking unit and hydro tester to avoid pipe damage during abnormal shutdown.

5. Layout Design Avoidable Mistakes & Boyu Optimization Suggestions

1.❌ Mistake: Straightener installed after bucking station

✅ Solution: Straightening must finish before makeup; bent pipe will cause eccentric clamping, messy torque-turn curve and seal leakage. Boyu sets 3~5m buffer roller between straightener and bucking to stabilize pipe feeding.

2.❌ Mistake: Hydrostatic tester far separated from bucking unit

✅ Solution: Max transit distance between bucking outlet and hydro inlet controlled within 12m; install soft protective roller on conveying line to prevent thread scratch.

3.❌ Mistake Independent control cabinets for each machine

✅ Solution: Boyu supplies integrated central HMI, one screen to view straightness report, real-time torque-turn curve and hydrostatic pressure record, greatly reduce operator workload.

4.❌ Mistake Insufficient overhead crane clearance for large bucking unit

✅ Solution For YNJQ full rotational series, reserve ≥4.2m vertical clearance above machine frame during civil design, convenient large pipe hoisting.

6. Full Line One-Stop Service from Boyu Petro

As a full-set OCTG equipment manufacturer with ISO9001, ISO14001, ISO45001 and CE certificates, Boyu provides full layout service covering:

Free 2D workshop layout drawing design according to customer plant dimension and output target;

Integrated equipment production: bucking unit + straightener + hydrostatic tester + all supporting roller tables & conveying system;

Unified on-site installation, wiring linkage, FAT joint debugging;

After-sales 24/7 technical support, torque calibration and CNC system upgrade service;

Global project delivery, covering Middle East, Central Asia, Southeast Asia, North & South America markets.

Conclusion

The matching layout of bucking unit, straightener and hydrostatic tester directly determines the production efficiency and finished pipe qualification rate of the entire OCTG line. Linear layout fits mass standard pipe factories, while U-type compact layout suits repair yards and premium tubular workshops.

Boyu Petro’s integrated three-core equipment solution unifies mechanical conveying, hydraulic power and digital data system, eliminating disconnection between single machines. Whether you plan new workshop construction or old production line reconstruction, our engineering team can customize exclusive layout plan and equipment configuration according to your pipe specifications, daily output and plant space.