Gear pump

Tandem Cast Iron Hydraulic Gear Pump 6PT4F+4PTF SAE C 2/4-Bolt Series

Engineered with heavy-duty spheroidal graphite cast iron bodies and a universal SAE B 2/4-bolt combination mounting flange, the HENGYUHANG 6PT4F+4PTF tandem hydraulic gear pump delivers dual-circuit fluid power with front-stage peak pressures up to 350 bar (5,076 psi) and high volumetric efficiency exceeding 94%.

| Applications

Designed for severe-duty mobile machinery and high-flow industrial hydraulic power units, this cross-frame cast iron tandem pump independently powers heavy primary implements and high-demand secondary circuits on mining excavators, large wheel loaders, rotary drilling rigs, and heavy material handling cranes. Its universal SAE B combination 2/4-bolt mounting pattern allows direct retrofit onto both standard 2-bolt oval and rigid 4-bolt rectangular equipment mounting pads without structural alteration.

| Key Technical Specifications

Product Model: Hengyuhang Tandem Cast Iron Hydraulic Gear Pump 6PT4F+4PTF SAE B 2/4-Bolt Series

Brand Replacement: CASAPPA, PARKER, JIHOSTROJ, KAPPA, PERMCO OEM or as requested.

Displacement: Front Stage (Group 6PT4F Cast Iron): 20 to 135 cm³/rev; Rear Stage (Group 4PTF Cast Iron): 8 to 92 cm³/rev

Rotation Direction: Clockwise (R), counter-clockwise (L), reversible (upon request)

Speed Range: Min. speed 350 r/min; Max. speed 3000 r/min

Peak Pressure: Front stage up to 350 bar (5,076 psi); Rear stage up to 315 bar (4,568 psi)

| Overview of HENGYUHANG Tandem Cast Iron Hydraulic Gear Pump 6PT4F+4PTF SAE B 2/4-Bolt Series

The HENGYUHANG 6PT4F+4PTF SAE B 2/4-Bolt Series is an ultra-heavy-duty cross-frame tandem external gear pump that couples an extra-high-capacity Group 6 cast iron front pump stage (6PT4F) with a heavy-duty Group 4 cast iron rear pump stage (4PTF). Both pump bodies, front mounting cover, intermediate bracket, and rear cover are manufactured from high-tensile spheroidal graphite ductile iron , delivering superior fatigue strength, minimal bore expansion under cyclic hydraulic shocks, and high thermal stability. The 6PT4F front stage incorporates an induction-hardened, internal involute splined through-shaft coupling that drives the rear 4PTF stage with zero torsional deflection. Featuring a universal combination SAE B 2/4-bolt mounting flange (Centring pilot Ø 101.6 mm / 4.00" h8, 2-bolt diagonal spacing 146.0 mm / 5.75", 4-bolt rectangular pattern 89.7 × 114.3 mm / 3.53" × 4.50", Cover Code 00) and standard SAE splined or keyed drive shafts, this series offers 1:1 OEM drop-in interchangeability across leading international manufacturers including CASAPPA, Parker, Jihostroj, Permco, and David Brown.

| Dimension of HENGYUHANG Tandem Cast Iron Hydraulic Gear Pump 6PT4F+4PTF SAE B 2/4-Bolt Series

1

| Interface Data Needed with the Drawing (Dimensional Reference Table)

Interface ParameterEngineering Specification & Dimensional StandardNotes / Tolerance
Front Mounting FlangeSAE B Combination 2/4-Bolt universal flange (Catalogue Code 00)Dual-geometry pad conforming to SAE J744 / ISO 3019-1
Flange Centring PilotØ 101.6 mm (4.00 in)Pilot tolerance h8 (-0.012 / -0.054 mm), pilot depth 9.5 mm
2-Bolt Mounting Pattern146.0 mm (5.75 in) diagonal center-to-center hole spacingStandard 2-bolt SAE B oval pad alignment
4-Bolt Mounting Pattern89.7 mm × 114.3 mm (3.53 in × 4.50 in) rectangular bolt patternStandard 4-bolt SAE B rectangular pattern for heavy-duty mounting
Mounting Bolt Holes4 × Ø 14.3 mm (9/16 in) through clearance holesSuitable for 1/2"-13 UNC or M12/M14 high-tensile grade 10.9 bolts
Primary Drive ShaftSAE 13-tooth involute splined shaft (Catalogue Code 01)16/32 DP, 30° pressure angle, flat root side fit, major Ø 21.8 mm
Alternative Drive ShaftsSAE 15T spline (Code 02), SAE 7/8" keyed (Code 06), SAE 1" keyed (Code 03)Optional heavy-duty 14T 12/24 DP (Code 07.00, Ø 31.2 mm) available
Intermediate Through-DriveDedicated high-torque internal splined coupling (Group 6 to Group 4)High-strength alloy steel connecting front and rear drive gears
Front Stage Ports (6PT4F)4-bolt split flange (SAE Code 61 / Metric) or SAE O-ring boss / BSPPStandard Code A05/A06, E05/E06, G07/G08 per displacement
Rear Stage Ports (4PTF)4-bolt split flange (SAE Code 61 / Metric) or SAE O-ring boss / BSPPIndependent inlet/outlet or common combined inlet configuration
Housing ConstructionHigh-tensile spheroidal graphite ductile iron (QT500)Front cover, bodies, intermediate bracket, and rear cover
Seals MaterialStandard: NBR (-20 °C to +80 °C); Optional: FKM Viton (-10 °C to +200 °C) / HNBRAnti-extrusion backup rings for continuous high-pressure operation
Flange Fastening Torque100 – 115 N·m (1/2" grade 8 / M12 grade 10.9 bolts)Cross-tightened evenly in two stages

| Pump Installation Specifications HENGYUHANG Tandem Cast Iron Hydraulic Gear Pump 6PT4F+4PTF SAE B 2/4-Bolt Series

| Comprehensive Ordering Code Breakdown (Hengyuhang Tandem Cast Iron Structure)

Code structure — reference: 6PTF−D1/D2−R−C−S−P1/P2−M−B

Code PositionMeaning & Available Values
6PTFSeries designation (Group 6 Heavy-Duty Cast Iron Tandem Pump Series)
D1 (Front Stage Displacement)Selected from Group 6 ratings: 20, 25, 30, 36, 42, 50, 60, 70, 80, 90, 100, 115, 125, 135 cm³/rev
D2 (Rear Stage Displacement)Selected from Group 4 ratings: 08, 10, 13, 16, 18, 20, 25, 29, 32, 36, 40, 45, 51, 55, 63, 72, 81, 92 cm³/rev
R (Rotation Direction)R = Clockwise (viewed from shaft end); L = Counter-Clockwise; B = Reversible / Bi-directional
C (Front Mounting Cover)00 = SAE B 2/4-bolt combination flange (Pilot Ø 101.6 mm, 146 mm 2-bolt / 89.7×114.3 mm 4-bolt); 01 = SAE B 2-bolt; 02 = SAE C 4-bolt; 10 = SAE B 2-bolt heavy-duty
S (Drive Shaft Code)01 = SAE 13T spline (Ø 21.8 mm); 02 = SAE 15T spline (Ø 25 mm); 06 = SAE 7/8" straight keyed (Ø 22.22 mm); 03 = SAE 1" straight keyed (Ø 25.4 mm); 07.00 = SAE 14T spline (Ø 31.2 mm)
P1/P2 (Inlet/Outlet Port Dimensions)Flanged fittings SAE (A), metric (E), BSPP (G), or metric thread (M)
M (Seals Compound)N = NBR Buna-N (standard); V = FKM Viton; H = HNBR
B (Outboard Bearing Option)A = Without axial/radial force; B = With radial force; C = Heavy-duty axial and radial bearing package

| Reading Your Replacement Code

Code SegmentExample ValueMeaning & Configuration
Series & Stage Model6PTF.90/45Front Group 6 Cast Iron (90 cm³/rev) + Rear Group 4 Cast Iron (45 cm³/rev)
RotationRClockwise rotation when facing drive shaft extension
Mounting Flange00SAE B combination 2/4-bolt universal flange (Ø 101.6 mm pilot, 2-bolt & 4-bolt pads)
Drive Shaft01SAE 13-tooth involute splined shaft (16/32 DP, 7/8" nominal OD)
Port DimensionsA06A05 / A05A04Front stage SAE split flange ports / Rear stage SAE split flange ports
Seal CompoundNNitrile butadiene rubber (NBR) oil seals with fluoropolymer backup rings
Design RevisionAStandard direct factory production series

| Techspecs of HENGYUHANG Tandem Cast Iron Hydraulic Gear Pump 6PT4F+4PTF SAE B 2/4-Bolt Series

| Performance Data Across Displacements

Note: Reference test conditions: ISO VG 46 hydraulic mineral oil, T = 50 °C, ν = 30 mm²/s.

Front Stage — Group 6PT4F Cast Iron

Model CodeDisplacement (cm³/rev)Flow @ 1500 rpm (l/min)Continuous Pressure p1 (bar)Intermittent Pressure p2 (bar)Peak Pressure p3 (bar)Max Speed (r/min)Min Speed (r/min)
6PTF2020.030.02803103503,000350
6PTF2525.037.52803103503,000350
6PTF3030.045.02803103503,000350
6PTF3636.054.02803103503,000350
6PTF4242.063.02803103503,000350
6PTF5050.075.02803103503,000350
6PTF6060.090.02602903203,000350
6PTF7070.0105.02502803102,800350
6PTF8080.0120.02402703002,800350
6PTF9090.0135.02302602902,600350
6PTF100100.0150.02202502802,500350
6PTF115115.0172.52002302602,400350
6PTF125125.0187.51902202502,200350
6PTF.135135.0202.51802102402,000350

Rear Stage — Group 4PTF Cast Iron

Model CodeDisplacement (cm³/rev)Flow @ 1500 rpm (l/min)Continuous Pressure p1 (bar)Intermittent Pressure p2 (bar)Peak Pressure p3 (bar)Max Speed (r/min)Min Speed (r/min)
4PTF88.012.02002302503,000350
4PTF1010.015.02002302503,000350
4PTF1313.019.52002302503,000350
4PTF1616.024.02002302503,000350
4PTF1818.027.02002302503,000350
4PTF2020.030.02302502803,000350
4PTF2525.037.52302502803,000350
4PTF2929.043.52302502803,000350
4PTF3232.048.02502753003,000350
4PTF3636.054.02752903153,000350
4PTF4040.060.02752903153,000350
4PTF4545.067.52752903153,000350
4PTF5151.076.52502753003,000350
4PTF5555.082.52302502803,000350
4PTF6363.094.52302502803,000350
4PTF7272.0108.02002302503,000350
4PTF8181.0121.52002302503,000350
4PTF9292.0138.01601802103,000350

Note: Technical values represent nominal performance benchmarks. Combined multi-stage flow can exceed 300 l/min. Maximum continuous operating parameters are governed by cumulative input drive shaft torque ratings.

| Operating Conditions & Fluid Compatibility

ParameterPermissible Operating RangeRecommended Optimal Target
Working FluidMineral oil-based hydraulic fluids (HL / HLP to DIN 51524)High-quality anti-wear hydraulic oil
Operating Viscosity10 to 1000 mm²/s (cSt)20 to 80 mm²/s (cSt)
Max. Cold Start ViscosityUp to 1200 mm²/s (p < 10 bar, n < 1500 r/min)Pre-warm oil before applying heavy system loads
Fluid Temperature (NBR)-20 °C to +80 °C (-4 °F to +176 °F)+30 °C to +60 °C (+86 °F to +140 °F)
Fluid Temperature (FKM)-10 °C to +200 °C (+14 °F to +392 °F)Extreme temperature / synthetic fluid duties
Inlet Absolute Pressure0.8 to 2.2 bar absolute (12 to 32 psi)Recommended 0.9 to 1.1 bar at pump suction
Fluid Cleanliness ClassISO 4406 Class 20/18/15 (NAS 1638 Class 9)Class 19/17/14 (NAS 8) for extended service life

Advantages

Severe-Duty Cast Iron Construction

Both the Group 6 front stage and Group 4 rear stage feature spheroidal graphite ductile iron (QT500) housings, delivering exceptional fatigue resistance and structural stiffness under continuous pressures up to 280 bar and peak pressures reaching 350 bar (5,076 psi).

Universal SAE B Combination 2/4-Bolt Flange

Incorporates a dual-geometry flange (Cover Code 00) accommodating both 2-bolt oval and 4-bolt rectangular mounting patterns (Pilot Ø101.6 mm / 4.00"), maximizing inventory versatility across diverse machine fleets.

Massive Dual Independent Flow Capability

Combines a high-displacement Group 6 front section (up to 135 cm³/rev) with a heavy-duty Group 4 rear section (up to 92 cm³/rev), delivering total combined delivery flows exceeding 300 l/min to independently power heavy hydraulic functions without cross-circuit pressure drops.

Heavy-Duty Group 6 Through-Drive Splined Coupling

Equipped with an oversized, induction-hardened internal involute splined through-drive connection engineered to transmit the full downstream drive torque under continuous high-load duty cycles.

High Volumetric Efficiency (>94%)

Micro-finished high-precision gear pairs and hydrostatically balanced floating thrust plates minimize internal leakage and maintain consistent volumetric efficiency across wide speed and pressure ranges.

Acoustic & Vibration Damping

Heavy cast iron construction naturally absorbs mechanical resonance and fluid pulsation, operating significantly quieter than conventional aluminum pumps in heavy equipment operator environments.

Reference

Series Architecture & Displacements

  • Series Nomenclature: HENGYUHANG Tandem Cast Iron Hydraulic Gear Pump 6PT4F+4PTF SAE B 2/4-Bolt Series

  • Front Stage (Group 6PT4F Cast Iron): Displacements from 20.0 to 135.0 cm³/rev (14 displacement steps).

  • Rear Stage (Group 4PTF Cast Iron): Displacements from 8.0 to 92.0 cm³/rev (18 displacement steps).

  • Flange Standard: SAE B Combination 2/4-Bolt universal mount (Cover Code 00, Pilot Ø101.6 mm / 4.00").

  • Drive Shaft: SAE 13T spline (Code 01) or optional SAE 15T / keyed drive shafts.

  • Intermediate Coupling: Dedicated heavy-duty Group 6 to Group 4 internal splined through-drive coupling.

Targeted Interchangeability & Replacement Matrix

The HENGYUHANG 6PT4F+4PTF SAE B 2/4-Bolt series provides 1:1 drop-in replacement compatibility across the following designated international hydraulic pump manufacturers and series:

  • CASAPPA: KP30, KP35, KP40, FDP30, HDP30, HDP35, FP30, FP40 series

  • PARKER (Commercial Hydraulics / Parker): PGP330, PGP350, PGP315, PGP365, PGP620, PGP640, P20 series

  • JIHOSTROJ: QHD0, QHD1, QHD2, GHD0, GHD1, GHD2 series

  • DAVID BROWN: Heavy-duty cast iron tandem external gear pump series

  • METARIS: Heavy-duty cast iron commercial interchange gear pump series

  • PERMCO (PERMCOP): P76, P75 cast iron tandem series

  • KOMATSU: OEM construction machinery main implement / auxiliary hydraulic pump replacement series

  • CATERPILLAR: Heavy earthmoving equipment OEM replacement hydraulic gear pump series

  • KAYABA (KYB): KFP series heavy-duty hydraulic gear pumps

Brand Replacement

The HENGYUHANG 6PT4F+4PTF SAE B 2/4-Bolt series is precision-engineered as a direct 1:1 heavy-duty replacement for premier international gear pump lines, notably CASAPPA KP/FP/HDP, PARKER PGP300/600, JIHOSTROJ QHD/GHD, and PERMCO P75/P76. Every pump undergoes 100% factory dynamic testing across its full speed and pressure envelope to verify volumetric efficiency, mechanical output, and multi-circuit pressure isolation. Utilizing standard SAE B centering dimensions (Ø101.6 mm / 4.00") and precision 13-tooth involute splined drive shafts, Hengyuhang pumps allow equipment manufacturers and service engineers to perform direct drop-in field replacements without piping rework, bracket redesign, or system modifications. Custom displacement pairings, shared or separate suction ports, and specialized shaft extensions are fully supported with rapid turnaround.

Applications

  • Heavy Earthmoving & Mining Machinery: Main boom, arm, and swing circuits paired with high-flow auxiliary implement or cooling fan circuits on large mining excavators, wheel loaders, and dozers.

  • Drilling & Piling Rigs: High-torque rotary head drives, feed cylinders, and auxiliary mast winches on hydraulic rotary drilling rigs, pile drivers, and continuous miners.

  • Heavy Material Handling & Port Equipment: Main mast hoisting and auxiliary power steering/braking circuits for container reach stackers, heavy rough-terrain cranes, and straddle carriers.

  • Forestry & Scrap Processing Equipment: Timber forwarders, log loaders, scrap metal shredders, heavy hydraulic shearing machines, and high-tonnage balers.

  • Heavy Industrial Hydraulic Power Units (HPUs): Central hydraulic power stations, hydraulic forging presses, high-capacity injection molding machines, and municipal refuse compactor stations.

Package & Shipping

Packaging TypeHeavy-duty export corrugated carton with custom molded shock-absorbing foam inserts; sea-freight orders packed in fumigation-free wooden cases
Port ProtectionHeavy-duty threaded plastic port plugs and shaft sleeve protectors installed
Corrosion PreventionExternal rust-preventive oil coating and vapor-corrosion inhibitor (VCI) polybag wrapping
Selling UnitSingle item (MOQ = 1 piece for standard models)
Package DimensionsApprox. 560 mm × 300 mm × 280 mm (varies with displacement pairing)
Gross WeightApprox. 42.0 – 58.5 kg (depending on displacement configuration)
Standard Lead Time3 – 5 business days for stocked components; 15 – 25 business days for volume OEM production
Shipping MethodsGlobal express air freight (DHL / FedEx / UPS / TNT) for urgent maintenance; Sea freight / Air cargo for wholesale orders
OEM & CustomizationPrivate label laser marking, customer part numbering, and custom displacement combinations supported

Why Choose Hengyuhang?

  • Direct Factory Precision Manufacturing & CNC Excellence: Manufactured in our state-of-the-art production facility equipped with high-precision 4-axis and 5-axis CNC machining centers, automated gear hobbing, and CNC gear tooth profile grinding (Ra < 0.2 μm) to ensure superior surface finish, ultra-tight internal clearances, and maximum volumetric efficiency.

  • 100% Full-Cycle Multi-Parameter Factory Inspection: Every single pump undergoes computerized testing before packaging, verifying flow rate at rated speed, volumetric efficiency (>94%), mechanical efficiency, continuous and peak pressure hold, internal bypass, and noise spectrum. Zero untested units leave the factory.

  • Seamless 1:1 OEM Drop-In Interchangeability: Dimensionally matched to European, SAE, and DIN standards, providing 1:1 direct mechanical interchangeability across global brands (Casappa, Parker, Jihostroj, Permco, David Brown, Komatsu, Caterpillar, etc.) with zero mounting modifications required.

  • Flexible Engineering Customization & Rapid Prototyping: Supported by a senior fluid power engineering team, offering custom displacement combinations, specialized shaft tapers, splines, integrated priority or relief valves, and non-standard port orientations with rapid sample prototyping and low MOQ requirements.

  • Robust Supply Chain, Extensive Inventory & Fast Global Dispatch: Extensive raw material stock of high-grade spheroidal graphite ductile iron castings, precision gear sets, and bearing assemblies enables rapid assembly and 48–72 hour dispatch for emergency breakdown replacements, supported by complete export logistics.

  • 12-Month Comprehensive Warranty & Lifetime Technical Support: All pumps are backed by a comprehensive 12-month manufacturer warranty against defects in materials and workmanship, supplemented by 24/7 engineering consultation, CAD drawing verification, and lifecycle technical assistance.

Tandem Cast Iron Hydraulic Gear Pump Group 6PT4F+4PTF SAE B 2/4-Bolt Combination Flange Series (20.00~135.00 + 8.00~92.00 cm³/rev) is an ultra-heavy-duty, all-cast-iron multi-stage external gear pump engineered for severe off-highway mobile machinery and high-tonnage industrial hydraulic systems requiring high-volume primary circuit delivery paired with heavy auxiliary hydraulic power. Featuring an industry-standard SAE "B" combination 2-bolt and 4-bolt pilot mounting flange (spigot centering pilot Ø101.6 mm / 4.000 in with 9.4 mm / 0.370 in pilot depth, 146.0 mm 2-bolt center-to-center spacing, and 90.0 × 90.0 mm 4-bolt square pattern with 4 × Ø14.5 mm clearance holes, front cover code 03), this heavy dual-section assembly couples a massive Group 6 ductile cast-iron front pump (6PT4F) with a versatile Group 4 ductile cast-iron rear pump (4PTF) via a high-strength through-drive internal spline coupling shaft. Built with 100% high-density spheroidal graphite cast iron across front covers, gear housings, intermediate coupling bodies, and rear covers, the pump exhibits exceptional mechanical fatigue resistance under continuous working pressures (p1) up to 280 bar (4,060 psi) on the primary stage and peak pressure spikes (p3) reaching 350 bar (5,076 psi). Featuring 14 standardized displacement sizes on the primary 6PT4F stage (20.0 to 135.0 cm³/rev) and 18 standardized displacement sizes on the secondary 4PTF stage (8.0 to 92.0 cm³/rev), total combined displacement spans 28.00 up to 227.00 cm³/rev (delivering up to 338.00 L/min combined flow @ 1500 rpm). Equipped with case-hardened alloy steel integral gears, heavy-duty DU composite journal bushings, and hydrostatic axial pressure-balanced floating wear plates across both stages, the 6PT4F+4PTF SAE B 2/4-bolt combination series maintains volumetric efficiencies exceeding 94% under demanding heavy-duty continuous operations.

| Applications

The all-cast-iron 6PT4F+4PTF SAE B 2/4-bolt combination tandem hydraulic gear pump series is specifically engineered for severe off-highway equipment, heavy industrial power packs, and multi-circuit machinery requiring dual high-pressure hydraulic circuits with unequal flow sizing:

  • Heavy Wheel Loaders, Mining Excavators, and Earthmoving Equipment: Direct-mounts to transmission or engine auxiliary PTO drive pads utilizing either SAE B 2-bolt or 4-bolt interface configurations; the primary Group 6 pump provides massive flow to boom lift and bucket dump cylinder breakout circuits, while the secondary Group 4 pump powers priority steering systems, hydraulic pilot controls, and thermostatic cooling fans.

  • High-Horsepower Agricultural Tractors and Combine Harvesters: Delivers reliable independent dual-circuit power; the front 6PT4F stage feeds high-flow electro-hydraulic hitch linkages and hydrostatic steering drive motors, while the rear 4PTF stage supplies dedicated hydraulic power to front-end loaders and auxiliary implement control valves.

  • Municipal Heavy Refuse Compactors and Transfer Trailers: Direct-driven via transmission PTO gearboxes; the large front stage delivers high-volume continuous flow to main packing blade cylinders, while the secondary stage operates bin lifters, tailgate latching cylinders, and stabilizer legs simultaneously without mutual hydraulic pressure drops.

  • Rotary Drilling Rigs, Piling Machines, and Tunnel Boring Equipment: Supplies continuous high-pressure fluid under severe cyclic shock loads; the primary stage drives continuous hydraulic drill head rotation motors, while the rear stage operates mast elevation, crawler leveling, and auxiliary clamping cylinders.

  • Mobile Forestry Harvesters, Forwarders, and Timber Cranes: Fully cast-iron casing design withstands extreme hydraulic shock loads and continuous vibration; the front pump feeds high-flow felling head drive motors and boom slewing systems, while the rear pump handles timber clamping arms and hydraulic cooling systems.

  • Heavy Industrial Hydraulic Presses, Balers, and Shears: Operates as an energy-efficient dual-delivery high-low system; both stages combine for rapid low-pressure cylinder approach, after which the secondary stage unloads to tank and the primary cast-iron stage maintains high tonnage holding pressures up to 280 bar without thermal fatigue.

| Key Specifications Overview

ParameterSpecification
Series ArchitectureHeavy-Duty All-Cast-Iron Dual-Stage External Gear Pump (Group 6 Front 6PT4F + Group 4 Rear 4PTF)
Front Stage Displacement (6PT4F)20.00 ~ 135.00 cm³/rev (14 standardized sizes: 20, 25, 32, 40, 45, 50, 63, 70, 80, 90, 100, 112, 125, 135 cm³/rev)
Rear Stage Displacement (4PTF)8.00 ~ 92.00 cm³/rev (18 standardized sizes: 8, 10, 13, 16, 18, 20, 25, 29, 32, 36, 40, 45, 51, 55, 63, 72, 81, 92 cm³/rev)
Total Combined Displacement Range28.00 ~ 227.00 cm³/rev (modular dual-stage independent circuit pairing: V1 + V2)
Continuous Operating Pressure (p1)Front stage: 200 ~ 280 bar (2,900 ~ 4,060 psi); Rear stage: 160 ~ 275 bar (2,320 ~ 3,988 psi)
Intermittent Operating Pressure (p2)Front stage: 230 ~ 315 bar (3,335 ~ 4,568 psi); Rear stage: 180 ~ 290 bar (2,610 ~ 4,205 psi)
Max. Peak Pressure (p3)Front stage: 250 ~ 350 bar (3,625 ~ 5,076 psi); Rear stage: 210 ~ 315 bar (3,045 ~ 4,568 psi)
Operational Rotational Speed RangeMinimum speed: 350 min⁻¹; Maximum rated speed: 3000 min⁻¹
Volumetric Efficiency≥ 94% across both stages under rated continuous pressure and fluid viscosity
Hydro-Mechanical Efficiency≥ 89% ~ 92%
Body and Housing Construction100% heavy-duty spheroidal graphite ductile cast iron: front mounting flange, Group 6 gear body, intermediate reduction coupling body, Group 4 gear body, and rear end cover
Mounting Flange StandardSAE "B" 2/4-bolt combination flange (spigot centering pilot Ø101.6 -0.012/-0.047 mm / 4.000 in, pilot depth 9.4 mm / 0.370 in, 146.0 mm 2-bolt centers and 90.0 × 90.0 mm 4-bolt square pattern with 4 × Ø14.5 mm clearance holes, front cover code 03)
Primary Drive Shaft SpecificationStandard: SAE B Involute Spline 14 Teeth 12/24 Pitch (major Ø31.22 mm, shaft code 01, max allowable drive torque 480 Nm); Options: SAE C 1-1/4 in straight keyed (code 07, 450 Nm), 16-tooth M1.75 spline (code 08), or 17-tooth 12/24 pitch spline (code 06)
Intermediate Coupling MechanismHeavy-duty alloy steel internal spline through-drive coupling connecting Group 6 front stage and Group 4 rear stage (allowable intermediate torque limit: up to 280 Nm)
Hydraulic Port ConnectionsFront stage: Metric 4-bolt flanged ports (Code K01~K08 / S03~S11) or SAE 4-bolt split flange ports (Code A01~A07); Rear stage: Metric 4-bolt flanged ports (Code E01~E07) or SAE split flange ports
Rotation DirectionClockwise (R / Right-Hand) standard; Counter-Clockwise (L / Left-Hand) available upon request (viewed facing drive shaft)
Hydraulic Fluid CompatibilityMineral-oil-based hydraulic fluids (HL / HLP to ISO 6743/4; DIN 51524 Class 1 and 2); optimal viscosity range: 20 ~ 80 mm²/s (cSt)
Operating Temperature Range-20°C to +85°C (standard NBR seals); -15°C to +110°C (optional Viton FKM seals)
Assembly Tightening TorquesFlange mounting bolts: 110 ± 10 Nm; Front Group 6 tie-rod bolts: 140 ± 10 Nm; Rear Group 4 tie-rod bolts: 95 ± 5 Nm

| Technical Performance Matrix Across Available Stages

Stage Model CodeStage MaterialDisplacement
cm³/rev (in³/rev)
Operating Pressure (bar / psi)Speed Range (min⁻¹)Flow @ 1500 rpm
(L/min)
Input Power
@ 250 bar (kW)
Continuous (p1)Intermittent (p2)Peak (p3)Min. SpeedMax. Speed
Front Primary Stage (Group 6PT4F Ductile Cast Iron Series — SAE B 2/4-Bolt Interface)
6PT4F20Ductile Cast Iron20.00 (1.220)200 / 2,900230 / 3,335250 / 3,625350300030.0011.0
6PT4F25Ductile Cast Iron25.00 (1.526)200 / 2,900230 / 3,335250 / 3,625350300037.5014.0
6PT4F32Ductile Cast Iron32.00 (1.953)250 / 3,625270 / 3,915290 / 4,205350300048.0017.0
6PT4F40Ductile Cast Iron40.00 (2.441)250 / 3,625270 / 3,915290 / 4,205350300060.0022.0
6PT4F45Ductile Cast Iron45.00 (2.746)250 / 3,625270 / 3,915290 / 4,205350300067.5025.0
6PT4F50Ductile Cast Iron50.00 (3.051)280 / 4,060315 / 4,568350 / 5,076350300075.0028.0
6PT4F63Ductile Cast Iron63.00 (3.845)280 / 4,060315 / 4,568350 / 5,076350300094.5035.0
6PT4F70Ductile Cast Iron70.00 (4.272)280 / 4,060315 / 4,568350 / 5,0763503000105.0040.0
6PT4F80Ductile Cast Iron80.00 (4.882)280 / 4,060315 / 4,568350 / 5,0763503000120.0045.0
6PT4F90Ductile Cast Iron90.00 (5.492)280 / 4,060315 / 4,568350 / 5,0763503000135.0050.0
6PT4F100Ductile Cast Iron100.00 (6.102)280 / 4,060315 / 4,568350 / 5,0763503000150.0056.0
6PT4F112Ductile Cast Iron112.00 (6.835)280 / 4,060315 / 4,568350 / 5,0763503000168.0063.0
6PT4F125Ductile Cast Iron125.00 (7.628)280 / 4,060315 / 4,568350 / 5,0763503000185.0070.0
6PT4F135Ductile Cast Iron135.00 (8.238)250 / 3,625270 / 3,915290 / 4,2053503000200.0075.0
Rear Secondary Stage (Group 4PTF Ductile Cast Iron Series)
4PTF8Ductile Cast Iron8.00 (0.488)200 / 2,900230 / 3,335250 / 3,625350300012.005.7
4PTF10Ductile Cast Iron10.00 (0.610)200 / 2,900230 / 3,335250 / 3,625350300015.007.1
4PTF13Ductile Cast Iron13.00 (0.793)200 / 2,900230 / 3,335250 / 3,625350300019.509.2
4PTF16Ductile Cast Iron16.00 (0.976)200 / 2,900230 / 3,335250 / 3,625350300024.0011.3
4PTF18Ductile Cast Iron18.00 (1.098)200 / 2,900230 / 3,335250 / 3,625350300027.0012.8
4PTF20Ductile Cast Iron20.00 (1.220)230 / 3,335250 / 3,625280 / 4,060350300030.0016.3
4PTF25Ductile Cast Iron25.00 (1.526)230 / 3,335250 / 3,625280 / 4,060350300037.5020.4
4PTF29Ductile Cast Iron29.00 (1.770)230 / 3,335250 / 3,625280 / 4,060350300043.5023.7
4PTF32Ductile Cast Iron32.00 (1.953)250 / 3,625275 / 3,988300 / 4,350350300048.0028.4
4PTF36Ductile Cast Iron36.00 (2.197)275 / 3,988290 / 4,205315 / 4,568350300054.0035.2
4PTF40Ductile Cast Iron40.00 (2.441)275 / 3,988290 / 4,205315 / 4,568350300060.0039.1
4PTF45Ductile Cast Iron45.00 (2.746)275 / 3,988290 / 4,205315 / 4,568350300067.5044.0
4PTF51Ductile Cast Iron51.00 (3.112)250 / 3,625275 / 3,988300 / 4,350350300076.5045.2
4PTF55Ductile Cast Iron55.00 (3.356)230 / 3,335250 / 3,625280 / 4,060350300082.5044.8
4PTF63Ductile Cast Iron63.00 (3.845)230 / 3,335250 / 3,625280 / 4,060350300094.5051.4
4PTF72Ductile Cast Iron72.00 (4.394)200 / 2,900230 / 3,335250 / 3,6253503000108.0051.1
4PTF81Ductile Cast Iron81.00 (4.943)200 / 2,900230 / 3,335250 / 3,6253503000121.5057.5
4PTF92Ductile Cast Iron92.00 (5.614)160 / 2,320180 / 2,610210 / 3,0453503000138.0065.3

| Mechanical Drive Guidelines and Torque Limitations

Mechanical ParameterEngineering Specification and Limit
Primary Shaft Drive Torque Limit (T1_max)SAE Involute Spline 14 Teeth 12/24 Pitch (shaft code 01): 480 Nm (4,248 lbf in); SAE C 1-1/4 in Keyed Shaft (code 07): 450 Nm (3,982 lbf in); SAE Spline 17 Teeth (code 06): 520 Nm
Intermediate Coupling Torque Limit (T2_max)280 Nm (2,478 lbf in) max torque transfer capacity for heavy-duty internal spline through-drive coupling connecting Group 6 front and Group 4 rear stages
Cumulative Drive Torque Verification FormulaT_total = (V1 × p1) / (20 × π × η_hm) + (V2 × p2) / (20 × π × η_hm) ≤ T1_max
Secondary Stage Torque Verification FormulaT_rear = (V2 × p2) / (20 × π × η_hm) ≤ 280 Nm (safely protects through-drive intermediate internal spline coupling)
Stage Sizing and Sequencing Engineering RuleAlways position the large Group 6 ductile cast-iron stage at the front (6PT4F) and the Group 4 stage at the rear (4PTF) to optimize driveline stress distribution

| SAE B 2/4-Bolt Mounting Flange, Shaft and Port Details

Interface FeatureTechnical Standard and Dimension
Mounting Flange StandardSAE "B" 2/4-bolt combination flange (spigot centering pilot Ø101.6 -0.012/-0.047 mm / 4.000 in, pilot depth 9.4 mm / 0.370 in, front cover code 03)
Mounting Hole Pattern DimensionsDual-compatibility pattern: 146.0 mm (5.748 in) 2-bolt center-to-center spacing, and 90.0 × 90.0 mm (3.543 × 3.543 in) 4-bolt square pattern with 4 × Ø14.5 mm clearance holes
Primary Drive Shaft (Standard)SAE Involute Spline: 14 Teeth, 12/24 Pitch, major diameter Φ31.22 mm (shaft code 01, max allowable drive torque 480 Nm)
Primary Drive Shaft (Optional)SAE C 1-1/4 in straight keyed (Φ31.75 mm, key 7.95×7.95×38.1 mm, code 07, 450 Nm); 16-tooth M1.75 spline (code 08); or 17-tooth 12/24 pitch spline (code 06)
Intermediate Coupling ShaftHeavy-duty alloy steel internal spline through-drive coupling connecting Group 6 and Group 4 stages (allowable intermediate torque: up to 280 Nm)
Front Stage Port Connections (6PT4F)Metric 4-bolt flanged ports (Code K01~K08 / S03~S11), SAE 4-bolt split flange ports (Code A01~A07), or cylindrical straight threads
Rear Stage Port Connections (4PTF)Metric 4-bolt flanged ports (Code E01~E07), SAE 4-bolt split flange ports (Code A01~A07), or cylindrical straight threads

| Standard Interchangeability and Mounting Compliance

Standardization CategoryTechnical Compliance and Interchangeability Characteristics
Mounting Interface StandardConforms fully to international SAE J744 mounting standards for SAE B combination interfaces (centering pilot Ø101.6 mm, 146 mm 2-bolt centers and 90 × 90 mm 4-bolt pattern), providing universal physical interchangeability across both 2-bolt and 4-bolt machine mounting pads.
Drive Shaft StandardizationStandard 14-tooth involute spline conforms to SAE J498 / ANSI B92.1 (12/24 DP), enabling direct coupling to standard heavy-duty SAE B/C hydraulic drive adapters and PTO gearboxes without modification.
Hydraulic Port CompatibilityPorting options include standard 4-bolt split flange interfaces conforming to SAE J518 / ISO 6162-1 (Code 61) and metric flanged ports, providing complete plumbing compatibility with international standard hydraulic piping lines.
All-Cast-Iron Tandem ReplacementFunctions as a direct drop-in replacement for standard Group 6 / Group 4 heavy-duty all-cast-iron dual gear pumps operating on mining loaders, excavators, municipal refuse compactors, and high-pressure mobile power units.

| Technical Performance Matrix Across Available Stages

Stage Model CodeStage MaterialDisplacement
cm³/rev (in³/rev)
Operating Pressure (bar / psi)Speed Range (min⁻¹)Flow @ 1500 rpm
(L/min)
Input Power
@ 250 bar (kW)
Continuous (p1)Intermittent (p2)Peak (p3)Min. SpeedMax. Speed
Front Primary Stage (Group 6PT4F Ductile Cast Iron Series — SAE B 2/4-Bolt Interface)
6PT4F20Ductile Cast Iron20.00 (1.220)200 / 2,900230 / 3,335250 / 3,625350300030.0011.0
6PT4F25Ductile Cast Iron25.00 (1.526)200 / 2,900230 / 3,335250 / 3,625350300037.5014.0
6PT4F32Ductile Cast Iron32.00 (1.953)250 / 3,625270 / 3,915290 / 4,205350300048.0017.0
6PT4F40Ductile Cast Iron40.00 (2.441)250 / 3,625270 / 3,915290 / 4,205350300060.0022.0
6PT4F45Ductile Cast Iron45.00 (2.746)250 / 3,625270 / 3,915290 / 4,205350300067.5025.0
6PT4F50Ductile Cast Iron50.00 (3.051)280 / 4,060315 / 4,568350 / 5,076350300075.0028.0
6PT4F63Ductile Cast Iron63.00 (3.845)280 / 4,060315 / 4,568350 / 5,076350300094.5035.0
6PT4F70Ductile Cast Iron70.00 (4.272)280 / 4,060315 / 4,568350 / 5,0763503000105.0040.0
6PT4F80Ductile Cast Iron80.00 (4.882)280 / 4,060315 / 4,568350 / 5,0763503000120.0045.0
6PT4F90Ductile Cast Iron90.00 (5.492)280 / 4,060315 / 4,568350 / 5,0763503000135.0050.0
6PT4F100Ductile Cast Iron100.00 (6.102)280 / 4,060315 / 4,568350 / 5,0763503000150.0056.0
6PT4F112Ductile Cast Iron112.00 (6.835)280 / 4,060315 / 4,568350 / 5,0763503000168.0063.0
6PT4F125Ductile Cast Iron125.00 (7.628)280 / 4,060315 / 4,568350 / 5,0763503000185.0070.0
6PT4F135Ductile Cast Iron135.00 (8.238)250 / 3,625270 / 3,915290 / 4,2053503000200.0075.0
Rear Secondary Stage (Group 4PTF Ductile Cast Iron Series)
4PTF8Ductile Cast Iron8.00 (0.488)200 / 2,900230 / 3,335250 / 3,625350300012.005.7
4PTF10Ductile Cast Iron10.00 (0.610)200 / 2,900230 / 3,335250 / 3,625350300015.007.1
4PTF13Ductile Cast Iron13.00 (0.793)200 / 2,900230 / 3,335250 / 3,625350300019.509.2
4PTF16Ductile Cast Iron16.00 (0.976)200 / 2,900230 / 3,335250 / 3,625350300024.0011.3
4PTF18Ductile Cast Iron18.00 (1.098)200 / 2,900230 / 3,335250 / 3,625350300027.0012.8
4PTF20Ductile Cast Iron20.00 (1.220)230 / 3,335250 / 3,625280 / 4,060350300030.0016.3
4PTF25Ductile Cast Iron25.00 (1.526)230 / 3,335250 / 3,625280 / 4,060350300037.5020.4
4PTF29Ductile Cast Iron29.00 (1.770)230 / 3,335250 / 3,625280 / 4,060350300043.5023.7
4PTF32Ductile Cast Iron32.00 (1.953)250 / 3,625275 / 3,988300 / 4,350350300048.0028.4
4PTF36Ductile Cast Iron36.00 (2.197)275 / 3,988290 / 4,205315 / 4,568350300054.0035.2
4PTF40Ductile Cast Iron40.00 (2.441)275 / 3,988290 / 4,205315 / 4,568350300060.0039.1
4PTF45Ductile Cast Iron45.00 (2.746)275 / 3,988290 / 4,205315 / 4,568350300067.5044.0
4PTF51Ductile Cast Iron51.00 (3.112)250 / 3,625275 / 3,988300 / 4,350350300076.5045.2
4PTF55Ductile Cast Iron55.00 (3.356)230 / 3,335250 / 3,625280 / 4,060350300082.5044.8
4PTF63Ductile Cast Iron63.00 (3.845)230 / 3,335250 / 3,625280 / 4,060350300094.5051.4
4PTF72Ductile Cast Iron72.00 (4.394)200 / 2,900230 / 3,335250 / 3,6253503000108.0051.1
4PTF81Ductile Cast Iron81.00 (4.943)200 / 2,900230 / 3,335250 / 3,6253503000121.5057.5
4PTF92Ductile Cast Iron92.00 (5.614)160 / 2,320180 / 2,610210 / 3,0453503000138.0065.3


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