A copper alloy temper designation describes the condition created by casting, cold working, annealing, or heat treatment. It is neither the alloy grade nor a guaranteed hardness value. For cast bronze bushings, M02 and M07 are usually more relevant than the H-series tempers used for wrought products. Understanding this difference helps buyers avoid specifying a condition that does not match the product form.
What Is a Copper Alloy Temper Designation?
A UNS number such as C93200 or C95400 identifies composition; a temper designation identifies manufacturing or delivery condition. The product standard and drawing define properties and acceptance requirements.
ASTM B601 provides a unified temper system, but its codes are not complete material specifications. Parts of the same alloy can differ because of casting method, heat treatment, section size, or processing history. A code cannot replace a specified hardness or tensile value.
See our guide to the copper alloy designation system for more information about grades and composition.
Cast vs Wrought Copper Alloy Temper Designations
Many copper temper charts mainly cover wrought plate, sheet, rod, wire, and drawn copper tubing. O-series codes commonly describe annealed conditions; H-series codes describe cold-worked conditions. H02, or half-hard copper, is one example.
Cast copper alloys are formed in molds or by centrifugal or continuous casting, making M-series codes more relevant. A sheet or HVAC tube designation should not automatically be applied to a bronze bushing.
Drawn-temper copper tubing normally means wrought plumbing or refrigeration tube—not continuous-cast bronze tube. Aluminum codes such as O or T6 apply to aluminum products; aluminum bronze remains a copper alloy.
Copper Alloy Temper Codes Relevant to Cast Bronze Parts
The following codes commonly appear with cast bronze products:
| Code | Condition | Typical relevance |
|---|---|---|
| M01 | As-sand cast | Parts produced in sand molds |
| M02 | As-centrifugal cast | Bushings, rings, sleeves, and hollow round parts |
| M05 | As-permanent mold cast | Parts produced in reusable metal molds |
| M07 | As-continuous cast | Tube or bar stock for subsequent machining |
These are manufacturing conditions, not quality levels. Centrifugal casting often suits thick-walled, rotationally symmetrical parts. Continuous casting produces tube or bar stock for cutting and machining.
The suitable route depends on alloy, dimensions, quantity, required properties, and product standard. Even with the same UNS grade, M02 and M07 are not automatically interchangeable. Compare our centrifugally cast bronze bushings with continuous-cast bronze tubes.
How Temper Affects Copper Alloy Properties
Manufacturing condition can affect hardness, strength, ductility, machinability, and dimensional stability. Copper work hardening generally raises strength and hardness while reducing ductility; annealing can restore ductility.
Cast bronze must be assessed separately. Its mechanical properties also depend on composition, casting quality, section thickness, heat treatment, and test location. Data for pure copper or drawn tube should not be applied directly to a cast bushing.
Specify required values, test methods, sampling positions, and standards. For scales and alloy comparisons, see our guide to the hardness of copper and bronze.
How to Specify Temper on a Bronze Bushing Drawing
A useful inquiry identifies the alloy, product standard, casting condition, dimensions, tolerances, quantity, and inspection documents. State hardness or tensile limits instead of assuming the temper code supplies them.
A drawing that states only “bronze” is incomplete because it does not establish composition, casting route, or acceptance properties.
Check that alloy, temper, property values, and product form use compatible specifications. For an unfamiliar code, provide the referenced standard and revision. Never silently convert a wrought H-series temper to an M-series condition.
For replacements, also provide load, speed, lubrication, fit, temperature, and failure information. Agree before production whether material certificates, dimensional reports, or hardness inspection are required.
Custom Cast Bronze Parts to Your Drawing
JEDBUSHING manufactures custom bronze bushings, rings, wear plates, tubes, and other machined copper-alloy parts. Before production, we review the alloy, casting condition, dimensions, quantity, application, and inspection requirements. Production may include centrifugal casting, continuous casting, and finish machining.
Send us your drawing with the alloy, dimensions, quantity, and application details. We can review whether its material, manufacturing, machining, and inspection requirements are compatible.
Frequently Asked Questions
Must the temper code appear on the purchase order?
If temper is a contractual requirement, include it with the alloy, product standard, and property limits. This provides one acceptance basis.
Can a supplier identify temper from a finished bushing?
Not reliably from appearance alone. Hardness or metallographic testing may provide evidence, but original material and production records give stronger traceability.
What if the drawing and purchase order specify different conditions?
Production should pause until the buyer provides written clarification. The agreed alloy, condition, property requirements, and applicable standard should appear in the revised documents.
Does every cast bronze drawing need an M-series code?
No. A product standard or drawing may define the casting route and required properties without a separate code. Do not add one unless it is applicable and necessary.