Bushings and bearings
Non-ferrous alloy components manufactured from a drawing or sample.
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Graphite-Plugged Bronze Bushings
Bronze components with solid lubricant inserts, made to drawing for high loads, low speeds, oscillating motion or points with limited access for relubrication.
Itametais manufactures graphite-plugged bronze bushings in different alloys, dimensions and configurations. The bronze-alloy body, geometry and insert pattern are defined for each application, including large custom components weighing up to 1,500 kg per part, subject to technical feasibility assessment.
01 / 20What are graphite-plugged bronze bushings?
Graphite-plugged bushings are bronze components with solid lubricant inserts. They typically combine a bronze-alloy body, a machined sliding surface, holes or recesses distributed over the contact area, inserts installed in those recesses and a final finish defined by the drawing and mounting conditions.
During operation, the solid lubricant acts at the sliding interface and may reduce reliance on oil or grease. The commercial term “graphite-plugged” may refer to a graphite-based solid lubricant, without defining or disclosing the insert composition. Results depend on the specification and operating regime.
When this solution may be suitable
When correctly specified, bronze bushings with solid lubricant inserts may be considered where load, motion, environment or restricted access makes conventional relubrication difficult.
- High loads and low sliding speeds.
- Oscillating, reciprocating or intermittent motion.
- Frequent starts and stops or long periods under static load.
- Points with limited access for relubrication.
- Environments where oil or grease is undesirable.
- Equipment exposed to demanding operating conditions.
Suitability depends on load, speed, motion, temperature, mounting and the other operating conditions. One configuration does not automatically cover every duty.
Manufactured configurations
Geometry must match the motion, load direction, contact area and equipment assembly. These configurations are not interchangeable and are defined for each project.
- Cylindrical, flanged and split bushings, including half-bushings.
- Thrust washers, wear plates and slide plates.
- Axial and radial rings.
- Segmented solid lubricant bearings.
- Custom-engineered components and special formats made to drawing.
Bronze alloys selected for the project
Itametais works with a broad range of bronze alloys selected for the project requirements. Bodies may be manufactured in SAE 67, SAE 68, SAE 430, other SAE grades, ASTM or equivalent alloys, and special alloys specified by the customer, subject to technical feasibility.
Selection may consider load magnitude and direction, sliding speed and contact pressure, motion type and frequency, shock, vibration, operating temperature, shaft material and finish, clearances, interference, environment, geometry, and mechanical and dimensional requirements.
The alloy must be selected for the actual combination of requirements. No single alloy is suitable for every application.
Manufacturing processes
The bronze-body manufacturing route is selected according to alloy, geometry, dimensions, mass, quantity, tolerances, supply condition and application requirements.
- Phenolic sand casting.
- CO₂ sand molding.
- Centrifugal casting.
- Precision machining and drilling of insert recesses.
- Installation of solid lubricant inserts.
- Final finishing and inspection to project requirements.
Centrifugal casting is one available route; process selection depends on the characteristics of each component.
Insert layout development
Itametais machines and drills the recesses, distributes and installs the inserts, finishes the sliding surface and performs dimensional inspection of the completed component.
The insert pattern may follow the customer drawing in full or be developed and assessed by Itametais engineering according to geometry, contact area and direction of motion, with customer technical approval before manufacturing.
Insert diameter, quantity and spacing do not follow a universal pattern. They are defined for the project without assuming a specific solid-lubricant composition.
Self-lubrication and relubrication
When correctly specified for load, speed, motion, temperature and mounting conditions, graphite-plugged bronze bushings may reduce or, in technically validated applications, eliminate the need for recurring external relubrication.
The duty must be assessed for each self-lubricating bronze bushing, solid lubricant bearing or bronze component with solid lubrication. Wear, inspection and maintenance remain linked to the equipment and its operating regime.
Engineering and technical support
Development may start from a drawing, sample or application data. Any change, recovery or improvement is subject to technical assessment and customer approval.
- Made-to-drawing manufacturing or development from a sample.
- Reverse engineering and recovery of used components when feasible.
- Alloy selection or recommendation.
- Assessment of clearances, interference and mounting conditions.
- Definition of the insert pattern or execution of the customer-supplied layout.
- Resizing and improvement of existing designs.
- Technical support to match the component to its operating regime.
Supply conditions
The supply condition depends on the contracted drawing and specification. Components may be delivered at different manufacturing stages to integrate with the customer’s process.
- As-cast, rough-machined or pre-machined.
- Finished-machined.
- With insert recesses prepared.
- With the inserts installed.
- Finished and ready for assembly, as specified by the drawing.
Quality control
According to applicability, project specification and contracted requirements, the inspection plan may include:
- Chemical composition analysis.
- Hardness and tensile testing.
- Ultrasonic and liquid penetrant testing.
- Dimensional inspection and report.
- Raw-material certificate.
- Heat identification and traceability.
Applicable tests and documents are defined for each supply; they are not mandatory for every part.
Large graphite-plugged bushings — up to 1,500 kg per part
Itametais can manufacture bronze components with solid lubricant inserts weighing up to 1,500 kg per part, subject to assessment of the alloy, geometry, dimensions, process, tolerances and technical project requirements.
Factors that influence performance
Performance depends on the correct combination of material, design, equipment, installation and duty. Technical assessment considers:
- Bronze alloy, load, contact pressure, sliding speed and PV factor.
- Type, direction and frequency of motion.
- Insert pattern and contact-surface geometry.
- Temperature, mounting clearance and alignment.
- Shaft finish and hardness.
- Environmental contamination and installation quality.
- Frequency of starts and stops.
Applicable limits must be defined for the project; this assessment does not replace technical sizing of the assembly.
Potential benefits and industrial applications
With proper specification, the solution may help reduce reliance on external relubrication, serve maintenance-restricted points, operate under oscillating or intermittent motion, and extend intervals between interventions. These outcomes are not guarantees and depend on actual service conditions.
Each part must be developed or selected for its specific application. Graphite-plugged bronze bushings may be assessed for the following industries and equipment:
- Mining, crushers and crushing equipment.
- Steelmaking, metallurgy, ferroalloys and cement.
- Pulp and paper, sugar and ethanol.
- Power generation and hydroelectric plants.
- Presses, joints, guides and wear plates.
- Heavy equipment, material handling and process machinery.
- Special machinery and industrial mechanical systems.
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Do you need to manufacture or recover a graphite-plugged bushing?
Send us the drawing, sample or technical application data. Our team can assess the bronze alloy, geometry, clearances, insert pattern and supply condition best suited to the project.