Alloy and dimensions do not complete a brass or copper purchase description. A material’s temper is its supplied condition, created by its processing history. It changes forming behavior and mechanical response. A drawing that calls out C260 sheet but omits temper can leave an important production decision unresolved.
For fabricators and OEM buyers, temper belongs in the material callout alongside alloy, form, dimensions, and the governing product specification.
Temper Is a Material Condition, Not an Alloy Grade
Temper does not change an alloy’s nominal composition. A C260 brass temper, for example, may be supplied soft annealed, quarter hard, half hard, hard, or spring condition. Each condition gives the same alloy a different balance of strength, ductility, and elastic recovery.
For brass and copper products, the tempering process may include annealing, cold work, or both, depending on the desired condition. ASTM B601 classifies copper and copper-alloy temper designations by the manufacturing processes used and their resulting properties. It is not a product specification. The applicable product standard establishes the required mechanical values.
For that reason, H02 is not a complete material description. It identifies a conventional cold-worked condition, but it does not establish a universal property range. Required values vary by alloy, product form, section size, and the governing product specification.
How Common Brass and Copper Tempers Are Established
For common wrought brass and copper products, mills temper metal mainly through annealing and cold work.
Annealing relieves the effects of prior cold work and restores ductility. It is often selected when a part requires tight bends, drawing, flaring, or another demanding deformation before entering service. Compared with a more heavily worked condition of the same alloy and section, annealed material has lower strength and less springback.
Rolling and drawing create cold work. As deformation increases, strength and hardness rise while elongation falls. The resulting condition may provide higher yield strength and greater resistance to permanent set, but further forming becomes less forgiving.
A temper callout is not automatically a heat treatment callout. Some copper alloys use thermal treatments to develop specific properties, while common O and H conditions often identify annealed or cold-worked material.
Temper and Melting Temperature Are Different Specifications
Temper should not be confused with melting-range data. Engineers may consider the melting temps of metals when a process approaches fusion or a component will operate at elevated temperature. A metal melting temperature does not, however, identify the material condition needed for forming or final use.
The melting temp of copper concerns the base material, while the melting temp of bronze varies with alloy composition. Neither value tells a buyer which temper to order. Melting-temperature data serves a different purpose from temper selection, which depends on the alloy, product form, and required mechanical response.
Reading Common Copper-Alloy Temper Designations
The table below shows several conventional temper designations used for copper and copper-alloy products. Availability varies by alloy and product form, and the designation alone does not establish universal mechanical values. Confirm the required properties for the exact alloy, product form, section size, and governing product specification.
|
Common condition |
ASTM designation |
Relative behavior within the same alloy and form |
Selection implication |
|
Soft annealed |
O60 |
Highest ductility and lower strength |
Supports demanding forming operations |
|
Quarter hard |
H01 |
Increased strength with retained forming margin |
Allows some further forming |
|
Half hard |
H02 |
Higher strength and lower ductility |
Requires closer review of bend geometry |
|
Hard |
H04 |
Higher strength with greater springback |
Best suited to limited downstream forming |
|
Spring |
H08 |
Higher yield strength and limited forming margin |
Suitable for spring applications where further forming is limited |
H58 (drawn general purpose) and H80 (hard drawn) are common tube temper designations. They should not be mapped onto the flat-product progression shown above.
How Temper Changes the Outcome
A temper selection affects more than the supplier’s stock description. It can change how material responds during processing and after the part enters service.
- Forming and shape retention: Tight bend radii and severe drawn features require an alloy-and-temper combination that can accommodate the necessary strain. Harder conditions reduce forming margin and increase springback. Softer conditions allow more deformation before cracking becomes a concern.
- Machining stability: Alloy remains the primary driver of chip control, cutting performance, and surface finish. Temper can still matter when substantial stock removal redistributes residual stress or later forming has tight dimensional-stability requirements. A harder condition is not automatically a machining upgrade.
How to Specify the Right Temper
Before releasing a purchase order, confirm:
- The required alloy and mill form
- The requested temper and governing product specification
- The relevant dimensions or section size
- Any acceptance criteria tied to load, deflection, or downstream operations
A stated temper does not remove the need to verify the property requirements of the finished part. When a design calls for a particular level of strength, conductivity, spring response, or formability, the specification should identify the criteria used to accept the material.
Explore Lewis Brass & Copper’s product collections to review brass, copper, and bronze forms. Our team can help buyers identify suitable material for the stated application.
FAQs
What is the difference between temper and hardness in metal?
Temper is the material condition created through manufacturing or thermal processing. Hardness is one measurable property that may result from that condition, along with tensile strength and elongation.
What does annealed temper mean for brass and copper?
An annealed temper is a softened condition produced to restore ductility after cold work. For common copper-alloy designations, O60 identifies soft-annealed material, although the governing product specification controls the required properties.
Which metal temper is best for bending and forming?
A soft-annealed condition often provides the greatest forming margin within the same alloy and form. The right selection still depends on bend radius, section size, grain direction, and the forming method.
What do temper designations like H01, H02, and H04 mean?
These designations identify conventional cold-worked conditions. H01 is quarter hard, H02 is half hard, and H04 is hard. They do not guarantee the same mechanical values across different alloys or product forms.
Can you change the temper of a metal after it has been produced?
Yes. Subsequent cold work or an alloy-appropriate thermal cycle can change material condition. That work can also affect dimensions, surface condition, and mechanical properties, so it should be evaluated as part of the manufacturing process.
