HIGH PULSE CONSTANT PRESSURE HYDRAULIC HOSE 621 SERIES
OIL & FUEL · 225 bar working / 900 bar burst
↓Certifications & factory photos
- Hose Construction
- Structure:The Hose Consists of an Inner Tube, a Steel Wire Braided or Spiral Reinforcement Layer, and an Outer Cover
- Working Temperature:-40℃ to +120℃; for Water Medium: 0℃ to +70℃
- Hose Features
- Bend Radius:Minimum bend radius runs 50–630 mm over the range.
- Size Coverage:10 published codes spanning 6.4 mm to 50.8 mm bore, from 621-6 upward.
- Application:Suitable for Conveying Hydraulic Fluids Such as Glycol, Hydraulic Oil, Lubricating Oil, and Emulsions, Etc.
- Outer Diameter:Outer diameter 12.2–67.2 mm across the published bores.
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PRODUCT INTRODUCTION
621 Series — 225 bar, Constant Across Ten Bores
The 621 series is the lightest rung of our constant-pressure ladder: 22.5 MPa (225 bar) at every one of ten bores from 6.4 to 50.8 mm. The rating does not fall as the bore grows, which is what makes the range easy to stock.
Against the 628 series one rung up, the 621 body is thinner: 12.2 mm outside diameter at the 6.4 mm bore against 13.2 mm, on the same 50 mm minimum arc. Up to 13 mm the two series route identically, so the step up costs a millimetre of diameter rather than a re-design.
Burst is 90 MPa at every row, a 4:1 margin. The whole range runs 50 mm to 630 mm in bend radius, so a 2 inch line needs a 630 mm loop and a 1/4 inch line needs 50 mm — the same shape, scaled.
Data Display
| PRODUCT TYPE (Part Number) | AVAILABLE TYPES | AVAILABLE TYPES | AVAILABLE TYPES | AVAILABLE TYPES | INNER DIAMETER（ID） mm | HOSE OUTER DIAMETER mm | MAXIMUM WORKING PRESSURE W.P | psi | MINIMUM BURST PRESSURE B.P | psi | MINIMUM BENDING RADIUS Min.B.R |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 621-6 | AC | BC | CC | DC | 6.4 | 12.2 | 22.5 | 3,263 | 90 | 13,053 | 50 |
| 621-8 | AC | BC | CC | DC | 7.9 | 13.7 | 22.5 | 3,263 | 90 | 13,053 | 55 |
| 621-10 | AC | BC | CC | DC | 9.5 | 16 | 22.5 | 3,263 | 90 | 13,053 | 65 |
| 621-13 | AC | BC | CC | DC | 12.7 | 20.2 | 22.5 | 3,263 | 90 | 13,053 | 90 |
| 621-16 | AC | BC | CC | DC | 15.9 | 23.6 | 22.5 | 3,263 | 90 | 13,053 | 100 |
| 621-19 | AC | BC | CC | DC | 19 | 29.4 | 22.5 | 3,263 | 90 | 13,053 | 120 |
| 621-25 | CC | DC | 25.4 | 37.8 | 22.5 | 3,263 | 90 | 13,053 | 300 | ||
| 621-32 | CC | DC | 31.8 | 44.4 | 22.5 | 3,263 | 90 | 13,053 | 460 | ||
| 621-38 | CC | DC | 38.1 | 52.5 | 22.5 | 3,263 | 90 | 13,053 | 560 | ||
| 621-51 | CC | DC | 50.8 | 67.2 | 22.5 | 3,263 | 90 | 13,053 | 630 |
Values are reproduced from the official YIBO product page. psi columns = MPa × 145.038, rounded. 10 codes in this table; the order data sheet governs the batch.
Application & Selection
SUITABLE FOR CONVEYING HYDRAULIC FLUIDS SUCH AS GLYCOL, HYDRAULIC OIL, LUBRICATING OIL, AND EMULSIONS, ETC. HIGH PULSE CONSTANT PRESSURE HYDRAULIC HOSE 621 SERIES covers 6.4–50.8 mm across 10 published codes.
Assemblies of HIGH PULSE CONSTANT PRESSURE HYDRAULIC HOSE 621 SERIES are crimped and pressure-tested in-house, with metric / BSP / JIC / ORFS ends. MOQ on HIGH PULSE CONSTANT PRESSURE HYDRAULIC HOSE 621 SERIES is 100 m on standard items.
WHY THIS HOSE
Why 621 Is the Right Rung for Most Circuits
The ladder exists so a machine can be equipped from one bore series at four pressures. 621 is the rung where the wall is thinnest.
225 bar at All Ten
Every code from 6.4 mm to 50.8 mm is 22.5 MPa with 90 MPa burst. One class covers a whole machine harness.
1 mm Thinner Than 628
12.2 mm outside diameter at the 6.4 mm bore, against 13.2 mm on 628. Same 50 mm arc, less material.
Arc Identical to 628
50, 55, 65, 90, 100, 120, 300, 460, 560 and 630 mm are shared with the next rung up, so the routing does not change.
Sized for 200 bar Circuits
A pilot, steering or clamp circuit that runs at 180 to 200 bar sits under 225 with the 4:1 burst behind it.
Ten Bores, One Page
4 inch and 2 inch come off the same line, so a machine with three circuit sizes needs one purchase order.
Type Variants A to D
The AC, BC, CC and DC type columns show which bore sizes are offered in each build, with CC and DC available across the full range.
CONSTRUCTION
Thin Wall, Same Arc
Inner Tube
Oil-resistant synthetic rubber, bored 6.4 mm to 50.8 mm. The tube is common across the ladder; only the reinforcement above it changes.
Reinforcement
High-tensile steel wire rated 22.5 MPa with 90 MPa burst. This is the thinnest reinforcement of the four series, which is why the outside diameter stays small.
Cover
Abrasion-resistant cover, outside diameter 12.2 mm at the 6.4 mm bore rising to 67.2 mm at 50.8 mm.
APPLICATIONS
Where 225 bar Is Enough
Pilot and Control Lines
6.4 mm at a 50 mm arc, the tightest in the range, through a valve block.
Steering Circuits
9.5 and 12.7 mm at 225 bar, where a 65 or 90 mm arc suits a steering column.
Clamp and Fixture
Machine tool clamp circuits that hold at 200 bar and release without a spike.
Return and Case Drain
Lines where back-pressure is known and 225 bar is comfortably above it.
Agricultural Implements
Lift and steer circuits on implements that share one pressure class across sizes.
General Plant Hydraulics
Fixed skid piping where the weight and the outside diameter both matter for support.
HIGH-END INDUSTRY DIRECTIONS
Why a Ladder Beats a Single Range
Buyers increasingly want one bore series at several pressure classes, so a machine can be specified without changing families.
① One Bore Series, Four Rungs constant pressure hose
Trend: Machines are specified from a single bore family.
Dohose: 621 covers 6.4 to 50.8 mm at 22.5 MPa, matching 628, 635 and 642 in size.
② Weight Reduction lightweight hose
Trend: Every millimetre of outside diameter costs clearance and mass.
Dohose: 12.2 mm at the 6.4 mm bore, the thinnest of the four series.
③ Stores Simplification standard hose
Trend: One pressure class per machine family.
Dohose: Ten bores all at 22.5 MPa, so the bore is a flow decision.
④ Routing Unchanged on Upgrade retrofit hose
Trend: Retrofits keep the existing clamp positions.
Dohose: Identical 50 to 630 mm arcs with the 628 series.
⑤ Type Variants crimped hose
Trend: Buyers ask which bores are available in each build.
Dohose: AC, BC, CC and DC columns show it row by row.
⑥ Traceability traceable hose
Trend: Pressure class is recorded against the machine.
Dohose: Batch and test date marked on each cut length.
WHY DOHOSE
Seven Reasons Buyers Stay with Us
Tolerances on the Sheet
Bore, wall and bend radius for the High Pulse Constant Pressure Hydraulic Hose 621 Series are printed per code — 10 codes, 6.4–50.8 mm, no guessing between shipments.
Mixed Orders Welcome
Order several codes of the High Pulse Constant Pressure Hydraulic Hose 621 Series at once; 10 sizes in 6.4–50.8 mm are built on the same equipment.
No Dead Stock
Order metres, not coils: High Pulse Constant Pressure Hydraulic Hose 621 Series is cut to length, and mass runs published per code.
Crimped and Tested
Where a finished line is needed, High Pulse Constant Pressure Hydraulic Hose 621 Series is crimped and pressure-tested in-house before packing.
Freight-Ready
Coils of High Pulse Constant Pressure Hydraulic Hose 621 Series are bagged and palletised, with a 40HQ plan supplied before booking.
Your Name on It
The High Pulse Constant Pressure Hydraulic Hose 621 Series can be printed and packed under your brand for resale.
Quote in One Hour
Send bore, media and end type for High Pulse Constant Pressure Hydraulic Hose 621 Series — a firm price comes back within 1 hour.
FAQ
621 Series — Ten Questions
What is the working pressure of the 621 series?
Every code is 22.5 MPa (225 bar) with 90 MPa minimum burst, a 4:1 margin, from the 6.4 mm bore to the 50.8 mm bore. The rating does not fall as the bore grows, which is what a constant-pressure range means.
621 vs 628 — what actually differs?
Wall and pressure, not routing. Both share the 50 to 630 mm bend radius series and the same ten bores, but 621 is 22.5 MPa on a 12.2 mm outside diameter at the 6.4 mm bore, and 628 is 28 MPa on 13.2 mm.
Can a 621 hose be replaced by 628 on the same clamps?
Yes at the small bores, with a check on clearance. Up to 13 mm the arc is identical and the outside diameter grows by 1 mm, so a clamp sized for 621 usually takes 628. From 16 mm upward the diameters diverge further.
What is the bore range and the arc at each end?
Ten codes from 6.4 to 50.8 mm inside diameter, which is 1/4 inch to 2 inch, with minimum bend radius from 50 mm at the smallest to 630 mm at the largest. Outside diameter runs 12.2 mm to 67.2 mm.
Why is the outside diameter smaller than the next rung up?
Because the reinforcement only has to hold 22.5 MPa rather than 28 MPa, so the wall is thinner. At the 6.4 mm bore that shows as 12.2 mm against 13.2 mm, which is clearance in a crowded cabinet.
Why does a constant-pressure range suit a mixed machine?
Because bore stops being a pressure decision. All ten codes are 22.5 MPa, so a machine with three circuit sizes can be equipped from one class and the bore chosen for flow, without a pressure table taped to the store wall.
Which bore for a 200 bar pilot line?
The 6.4 or 7.9 mm code, at 225 bar with a 50 or 55 mm arc. A pilot line runs low flow at a fixed pressure, which is exactly the duty the smallest codes and the 4:1 margin are there for.
Which bore for a 1-1/2 inch return line?
The 38.1 mm code at 22.5 MPa on a 560 mm arc. Return lines are sized for flow and for pressure drop rather than for pressure, so the large bore of a constant-pressure range is the natural fit.
What is the minimum order and lead time?
100 m per size, cut to length, across 6.4 mm to 50.8 mm inside diameter. Production runs about 20 days from confirmation, and assemblies ship crimped and pressure-tested with metric, BSP, JIC or ORFS ends.
What does the 621 series cost per metre?
It is the lightest rung, so it prices below 628, 635 and 642 at the same bore: outside diameter 12.2 mm at the small end and 67.2 mm at 2 inch. Send bore, length, ends and destination and a firm figure comes back the same working day.
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