What stainless steel grades do you machine for bushings?

We routinely machine AISI 304, 316/316L, 303, 17-4 PH, and 440C stainless steel. Each grade is selected based on corrosion resistance, hardness requirements, and weldability.

Can you heat treat stainless steel bushings?

Yes. We offer precipitation hardening for 17-4 PH (H900, H1150, etc.) and through-hardening for 440C to achieve high Rockwell C hardness for wear applications.

What surface finishes can you achieve on stainless steel?

We typically achieve Ra 32 as machined. With grinding or electropolishing, we can achieve Ra 4-8 for sanitary or high-precision bearing surfaces.

How do you handle work hardening during machining?

Stainless steel work hardens if cut improperly. We use rigid setups, high-pressure coolant, and aggressive feed rates with coated carbide tooling to cut under the work-hardened layer.

Do you provide passivation?

Yes, we offer citric and nitric acid passivation to ASTM A967 standards to remove free iron and enhance corrosion resistance.

What are the shaft requirements for stainless bushings?

To prevent galling (adhesive wear), the shaft should be harder than the bushing or made of a dissimilar material. Lubrication is critical.

Can you machine split or flanged stainless bushings?

Yes, we machine all geometries including flanged, split, grooved, and threaded stainless steel bushings to your custom print.

Do you offer material traceability?

Every batch includes full heat lot traceability with chemical and physical test reports from the mill.

What is the maximum diameter you can turn?

We can turn stainless steel bushings up to 12 inches (300mm) in diameter and 24 inches (600mm) in length.

How do you inspect for cracks or defects?

Visual inspection is standard. Dye Penetrant Inspection (DPI) or Magnetic Particle Inspection (MPI) can be performed upon request for critical applications.

Manufacturing Dossier

Custom Stainless Steel Bushings Manufacturer & Supplier

High-corrosion resistance. Extreme durability. Verified hardness. We produce custom stainless steel bushings for harsh environments where failure is not an option.

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01. Material Capability Specification

We do not stock standard parts. Every bushing is machined from bar stock or tubing to your specific grade requirements.

Grade	Composition Notes	Heat Treatment	Typical Hardness
304 / 304L	18% Cr, 8% Ni. Standard “18-8”.	Annealed Only (Cannot harden)	~85 HRB
316 / 316L	Added Molybdenum for corrosion.	Annealed Only	~80 HRB
17-4 PH	Precipitation Hardening. High strength.	H900, H1025, H1150	30-45 HRC
440C	High Carbon Martensitic.	Through Hardened	55-60 HRC

02. Wear Pairing & Galling Control

Stainless steel is notorious for galling (cold welding) when rubbed against itself. For stainless bushings, the mating shaft selection is critical.

Dissimilar Hardness: Ensure the shaft is at least 5-10 HRC harder than the bushing.
Lubrication: Use grooves (spiral, figure-8) to retain grease or oil.
Coatings: Consider DLC (Diamond-Like Carbon) or hard chrome on the shaft.

Galling Risk Warning

Avoid 304 bushing on 304 shaft without lubrication.

03. Corrosion Environment Suitability

Marine (Saltwater)

Recommendation: 316L Stainless Steel. The molybdenum content resists pitting corrosion from chlorides.

Food & Pharma

Recommendation: 304 or 316L with electropolish (Ra < 10) to prevent bacterial growth traps.

High Load / Structural

Recommendation: 17-4 PH. Offers a good balance of corrosion resistance and high yield strength.

04. Quality Assurance & Inspection Evidence

We don’t just machine; we verify. Every shipment includes a quality dossier containing the following data points:

CMM Reports

Coordinate Measuring Machine reports for GD&T features like true position and profile.

Surface Roughness

Profilometer traces verifying Ra, Rz, and Rmax values on bearing surfaces.

Hardness Testing

Rockwell C (HRC) indentation reports for heat-treated batches.

XRF Analysis

Positive Material Identification (PMI) to confirm alloy composition before machining.

05. Manufacturing Process

Heavy-Duty Turning

Machining stainless steel requires rigidity. We use box-way lathes and high-pressure coolant (1000 PSI) to break chips and keep thermal expansion in check.

Post-Processing

After turning, parts may undergo centerless grinding for precision ODs, honing for IDs, or passivation cleaning.

06. Inspection Showcase

Micron-Level Verification

Our metrology lab is temperature controlled to 20°C ±0.5°C. This ensures that thermal expansion of stainless steel does not skew measurement results during final QC.

07. Core Industry Applications

Food Processing Conveyors
Pharmaceutical Packaging
Chemical Pumps & Valves
Marine Winches
Nuclear Power Instrumentation
Oil & Gas Downhole Tools

08. Technical FAQ

Can you hold +/- 0.0005″ on stainless?

Yes, but it often requires grinding or honing after turning, especially for thin-walled parts.

Do you offer 316L vs 316?

Yes. 316L has lower carbon to prevent carbide precipitation during welding. We confirm the grade via mill certs.

What is the lead time?

Standard is 15-20 days. Heat treatment adds ~3-5 days to the process.

How do you deburr stainless?

Stainless burrs are tough. We use abrasive flow machining or manual microscope deburring for critical edges.

Do you export?

Yes, we ship globally (DDP/DAP terms available) with proper packaging to prevent transit damage.

Can you make threaded bushings?

Yes, internal or external threads (UN, Metric, NPT) are machined in the same setup for concentricity.

What about magnetic permeability?

Annealed 300 series is non-magnetic. Cold work can induce magnetism. We can anneal parts to restore low permeability.

Minimum wall thickness?

Depends on diameter. Generally 0.040″ (1mm) is safe. Thinner requires review.

Do you offer laser marking?

Yes, we can laser engrave part numbers or batch codes directly on the bushing face.

Payment terms?

T/T. Net terms available for qualified recurring customers.

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09. Contact Information

Factory Location

Rongli Industrial Park, Dalang
Longhua District, Shenzhen, China

Direct Email

info@rapidaccu.com

Response time: < 24 Hours