Heat treatment of copper alloy material spring

1. Heat treatment of tin bronze Tin bronze cannot be strengthened by heat treatment, but must be cooled and deformed to improve its strength and elastic properties.

The main methods are:

(1) Fully annealed, used in the intermediate softening process to ensure the plastic deformation performance of large deformation processing in the subsequent process.

(2) Incomplete annealing is used to obtain plasticity consistent with the subsequent process before the elastic element is formed, so as to ensure a certain amount of forming deformation in the subsequent process and make the spring reach the performance.

(3) Stable annealing, used for the final heat treatment after the spring is formed, to eliminate cold working stress, and stabilize the shape and elastic properties of the spring.

Specification for heat treatment of tin bronze spring material

Material grade

Fully annealed

Incomplete annealing*

Stabilized tempering

temperature

Time(h)

temperature

Time(h)

temperature

Time(h)

QSn4~0.3

500~640

1~2

350~440

1~2

150~270

1~3

QSn4~3

500~580

1~2

350~440

1~2

150~260

1~3

QSn6.5~0.1

500~610

1~2

320~420

1~2

150~270

1~3

QSn6.5~0.4

550~600

1~2

360~410

1~2

200~280

1~3

Note: *The specification of incomplete annealing can be adjusted according to the subsequent forming deformation of the spring.

2. Heat treatment of beryllium bronze

The heat treatment of beryllium bronze can be divided into annealing treatment, solution treatment and aging treatment after solution treatment.

The return (return) fire treatment is divided into:

(1) Intermediate softening annealing can be used as a softening procedure in the middle of processing.

(2) Stabilized tempering is used to eliminate the processing stress generated by the precision spring and calibration, and stabilize the external dimensions.

(3) Stress relief tempering is used to eliminate machining stress generated during machining and calibration.

Specification for heat treatment of beryllium bronze spring material

Material grade

Intermediate softening annealing

Stabilized tempering

Stress relief

temperature

Time(h)

temperature

Time(h)

temperature

Time(h)

QBe1.7

540~560

2~4

110~130

4~6

200~250

1~2

QBe1.9

540~560

2~4

110~130

4~6

200~250

1~2

QBe2

540~560

2~4

110~130

4~6

200~250

1~2

QBe2.15

540~560

2~4

110~130

4~6

200~250

1~2

Specification for solution treatment and time efficiency treatment of beryllium bronze spring material

material

Grade

Solution treatment

Processing purpose and scope of use

Aging treatment

Temperature ℃

Thickness/time (min)*

Temperature ℃

Time h

QBe1.7

QBe1.9

QBe2

QBe2.15

800±10

0.1~1.0

/5~9

The grains are easy to grow, suitable for thicker and coarser materials

Plate/belt/wire

315±5

diameter

5~30

320±5

Y state: 1~2

Y2 state: 2

C state: 2~3

780±10 1.0~5.0 /12~30

Good comprehensive performance, used for softening treatment and tissue preparation before aging

760±10 5.0~10 /25~30

Obtain a fine grain structure, which is beneficial to improve the fatigue strength of the spring

Note: The holding time of solution treatment has a great influence on the grain size of the material and the performance after precipitation hardening. It should be determined by the diameter and thickness of the material and through experiments. The aging treatment can be cooled in the air after the holding time is over.

3. Heat treatment of silicon bronze wire

Silicon bronze is a Cu-si-Mn ternary alloy. It has good strength, hardness, elasticity, plasticity and wear resistance, and its hot and cold processing performance is also better. It cannot be strengthened by heat treatment and can only be used in annealed and processed hard conditions. After the spring is formed, only 200~280℃ stress relief tempering treatment is required. Note: Some of the materials in this series have been summarized by referring to the “Aeronautical Manufacturing Engineering Manual”, and after practice, they have been revised, supplemented, and improved.