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CNC Turned Stainless Steel Pump Sleeve with Precision ID Bore and Hard Chrome Plated for Corrosion Resistance

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Mrs. Yang

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CNC Turned Stainless Steel Pump Sleeve with Precision ID Bore and Hard Chrome Plated for Corrosion Resistance

Detail Information

Product Description

Detail Information

Material Options:

SS 316, SS 304, 17-4 PH, Duplex 2205

ID Bore Tolerance:

H7 (+0.000/-0.02mm)

Concentricity:

0.01mm Max (ID To OD)

Surface Finish:

Ra 0.4 (seal OD), Ra 1.6 (ID)

Hard Chrome Thickness:

0.05-0.10mm (optional)

Chrome Hardness:

65-70 HRC

Product Description

CNC Turned Stainless Steel Pump Sleeve for Centrifugal and Industrial Pumps

A pump sleeve sits on the shaft between the impeller and the bearing housing, protecting the shaft from wear at the seal and packing locations. When the mechanical seal or packing runs against the shaft, it gradually wears a groove into the metal. A replaceable sleeve takes that wear instead of the shaft - when the sleeve wears out, you replace a $20 sleeve instead of a $500 shaft.

Sounds simple. The engineering challenge is in the fits. The sleeve needs to slide onto the shaft with a close clearance fit (H7/g6 or similar), run true to within 0.01mm (so the seal sees a consistent surface), and not creep or rotate on the shaft under operating conditions. Most pump sleeves are secured with a setscrew, a key, or an interference fit at one end.

We turn pump sleeves from SS 316 or SS 304 round bar stock. The ID (shaft bore) is the most critical dimension - it needs to be round, straight, and on-size for a consistent fit on the shaft. We bore the ID in the same chucking as the OD to maintain concentricity. The OD (seal surface) needs to be smooth (Ra 0.4 for mechanical seals, Ra 0.8 for packing) and hard enough to resist wear. For extended life in abrasive pump applications, we can hard chrome plate the OD and grind it to final dimension.

The decision between SS 304 and SS 316 is straightforward for pump sleeves. If the pump handles water, mild chemicals, or food products, 304 is fine. If it handles seawater, chlorides, or corrosive chemicals, use 316. The cost difference is about 25-30% per piece, but a corroded sleeve in a chemical pump is a pump failure, so the premium is almost always justified for corrosive service.

Key Features

Precision ID Bore: Shaft bore held to H7 tolerance class (+0.000/-0.02mm for common sizes). Bore roundness within 0.005mm. Concentricity between ID and OD within 0.01mm. Consistent bore means consistent shaft clearance and no wobble.
Seal Surface Finish: Ra 0.4 for mechanical seal applications, Ra 0.8 for packing applications. Achieved with finish turning passes using sharp carbide inserts. Consistent surface finish extends seal life.
Hard Chrome Option: OD hard chrome plated (0.05-0.10mm) and ground to final dimension for extended wear life in abrasive slurries and high-pressure seal applications. Chrome surface hardness 65-70 HRC. Wear life 3-5x unplated sleeves.
Anti-Rotation Feature: Setscrew hole, keyway slot, or dowel pin hole for securing the sleeve to the shaft. Prevents sleeve rotation relative to the shaft, which would cause fretting and accelerated wear.
Shoulder or Step Design: Optional shoulder at one or both ends for axial positioning on the shaft. Shoulder face perpendicular to bore axis within 0.01mm. Ensures the sleeve sits square on the shaft.

Technical Specifications

Product Name	CNC Turned Stainless Steel Pump Sleeve
Material Options	SS 316 (standard for pump service), SS 304 (non-corrosive), 17-4 PH (high strength), Duplex 2205 (severe service)
Tolerance	H7 (ID bore), +/-0.01mm (OD), +/-0.05mm (length)
Concentricity	0.01mm max (ID to OD)
Surface Finish	Ra 0.4 (seal OD), Ra 1.6 (ID), Ra 3.2 (non-critical)
Hard Chrome Plating	0.05-0.10mm (optional), 65-70 HRC surface hardness
Certifications	ISO 9001:2015, IATF 16949, RoHS, CE, REACH
Lead Time - Prototype	3-7 days
Lead Time - Production	7-15 days
MOQ	1 piece (prototype), 50+ (production)
Origin	Dongguan, China

Applications

Centrifugal Pumps: Shaft sleeves for ANSI and API process pumps, vertical turbine pumps, multistage pumps. SS 316 for chemical and petrochemical service. SS 304 for water and general industrial.
Slurry Pumps: Hard chrome plated sleeves for mining, dredging, and mineral processing pumps. The chrome layer resists abrasion from solid particles in the pumped slurry.
API Process Pumps: Refinery pump sleeves, chemical plant pump sleeves, offshore platform pump sleeves. SS 316 or Duplex 2205 for NACE-compliant sour service.
Food & Sanitary Pumps: SS 316L sleeves for dairy, beverage, and pharmaceutical pumps. Electropolished seal surfaces for CIP (clean-in-place) compatibility.
Water Treatment Pumps: Municipal water pump sleeves, wastewater pump sleeves, RO desalination pump sleeves. SS 316 for saltwater and brackish water applications.
Boiler Feed Pumps: High-temperature pump sleeves for power generation. SS 316 or 17-4 PH for continuous operation at 150C+.

Why Choose Sinbo Precision

Pump Sleeve Experience: We've machined thousands of pump sleeves - from 25mm bore x 50mm OD utility pump sleeves to 150mm bore x 200mm OD API pump sleeves. We understand the fit requirements, the seal surface specifications, and the anti-rotation features.
Single-Setup Bore + OD: We turn the ID bore and OD in a single chucking, guaranteeing 0.01mm concentricity. No secondary boring operation. No datum shift. Every sleeve comes out with bore and OD perfectly concentric.
Hard Chrome + Grind: For abrasive pump applications, we hard chrome plate the OD (0.05-0.10mm) and then cylindrical grind to final dimension. Chrome provides 3-5x the wear life of bare stainless steel. We manage the plating process from end to end.
Multiple Material Options: SS 304, SS 316, SS 316L, 17-4 PH, Duplex 2205 - we stock or can source all standard pump sleeve materials. Material certificates with chemical composition and mechanical properties. PMI verification on critical orders.
Quick Turnaround: Pump sleeve failures are usually unplanned. We keep common sizes (25-100mm bore) in SS 316 bar stock at all times, enabling 3-5 day turnaround on emergency orders. Standard orders run 7-10 days.
Reverse Engineering: If you have a worn sleeve but no drawing, send us the sleeve (or measurements). We'll reverse-engineer the dimensions, identify the material (PMI testing), and quote a replacement. This happens more often than you'd think.

Manufacturing Process

DFM Review: Review sleeve dimensions for shaft fit (clearance class, tolerance). Confirm seal surface requirements (mechanical seal vs packing). Check anti-rotation feature (setscrew, keyway, interference fit). Material selection for pump service.
Material Preparation: SS 316 or SS 304 round bar stock. Material certificates verified. Cut to length. Center-drilled for tailstock support during turning.
CNC Turning: Bore ID to H7 tolerance. Turn OD to +/-0.01mm. Face both ends. Groove for O-rings or snap rings. Drill and tap setscrew hole. Turn shoulder (if specified). All in single chucking for concentricity.
Surface Treatment (optional): Hard chrome plating on OD (0.05-0.10mm). Post-plating cylindrical grinding to final OD dimension. Passivation for non-plated sleeves.
Inspection: CMM measurement of ID (bore diameter, roundness, cylindricity). OD measurement. Concentricity ID-to-OD. Surface finish on seal surface (profilometer). Setscrew thread gauging. Shoulder perpendicularity.
Packaging: Individual protective wrapping (plastic sleeve or VCI paper). Prevents surface damage during storage and transit. Labeled with part number, material, and dimensional data.

Frequently Asked Questions

Q: SS 304 or SS 316 for my pump sleeve?

A: If the pump handles water, oil, or mild chemicals, 304 is fine. If it handles anything corrosive - chlorides, seawater, acids, brine, process chemicals - go 316. For especially aggressive environments, consider 17-4 PH (high strength, good corrosion resistance) or Duplex 2205 (superior corrosion and stress corrosion cracking resistance).

Q: Do I need hard chrome on the seal surface?

A: For clean water pumps with mechanical seals, usually no - bare SS 316 works fine. For slurry pumps, pumps handling abrasive particles, or pumps with packing (which is more abrasive than mechanical seals), hard chrome extends sleeve life 3-5x. The cost premium is about 30-40% per sleeve but you replace it less often.

Q: What tolerance do I need on the shaft bore?

A: H7 (ISO tolerance class) is standard for pump sleeves. This gives a close clearance fit on an h6 shaft. For example, a 50mm H7 bore is +0.000/+0.025mm, fitting with a 50mm h6 shaft of -0.000/-0.016mm. Result: 0.016-0.041mm clearance. Tight enough to prevent sleeve wobble, loose enough to slide on by hand.

Q: Can you reverse-engineer a worn sleeve?

A: Yes. Send us the worn sleeve and we'll measure it, identify the material (PMI testing), and make a replacement. Worn sleeves are typically oversized on the ID (from shaft wear) and undersized on the OD (from seal wear), so we interpolate the original dimensions. If you can provide the shaft diameter, we'll size the bore correctly.

Q: What's the maximum sleeve length you can machine?

A: Up to 600mm on our standard CNC lathes with tailstock support. For sleeves longer than 600mm (some vertical turbine pump sleeves), we can bore on a horizontal boring machine. Longer sleeves need support at both ends during turning to prevent deflection.

Q: How fast can you make an emergency replacement?

A: 3-5 days for standard SS 316 sleeves in common bore sizes (25-100mm), assuming material is in stock. Hard chrome adds 3-5 days. We've done same-day turnaround for local customers in Dongguan with a pump down situation.

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Sinbo Precision Mechanical Co., Ltd.

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Battery Terminal Connector

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products details

CNC Mechanical Parts

CNC Turning Parts

CNC Milling Parts

CNC Machining Services

Cold Forging Parts

CNC Turning Milling Parts

CNC Aluminum Parts

CNC Stainless Steel Parts

CNC Brass Parts

CNC Stamping Parts

Machining Plastic Parts

Bending Sheet Metal Parts

New Energy Auto Parts

Energy Storage Connectors

Contactor Terminal

Battery Terminal Connector

CNC Manufacturing Solutions

CNC Turned Stainless Steel Pump Sleeve with Precision ID Bore and Hard Chrome Plated for Corrosion Resistance