The length of copper annealing time has nothing to do with hardness

It is related that the shorter the annealing time, the higher the hardness, and vice versa.

Annealing is a metal heat treatment process.

This refers to the slow heating of metal to a certain temperature, holding it for a sufficient period of time, and then cooling it at a suitable rate. The purpose is to reduce hardness and improve machinability; Eliminates residual stresses.

Stabilize the size and reduce the tendency of deformation and cracking; Refine the grains, adjust the tissue, and eliminate tissue defects. To be precise, annealing is a heat treatment process for materials, including metallic materials and non-metallic materials. Moreover, the annealing purpose of new materials is also similar and different from that of traditional metal annealing.

Commonly used annealing processes are:

Fully annealed. It is used to refine medium and low carbon steel.

Coarse superheated microstructure with poor mechanical properties after casting, forging and welding. The workpiece is heated to ferrite.

All converted to austenite.

The temperature is 30 50 above the temperature, keep warm for a period of time, and then slowly cool with the furnace, and the austenite transforms again during the cooling process, which can make the structure of the steel thinner.

Spheroidized annealing. It is used to reduce tool steel and bearing steel.

High hardness after forging. The workpiece is heated to 20 40 above the temperature at which the steel begins to form austenite, and after heat warming, it is slowly cooled, and in the cooling process the pearlite.

The lamellar cementite in the sheet becomes spherical, which reduces the hardness.

Isothermal annealing. It is used to reduce the high hardness of some alloy structural steels with high nickel and chromium content for machining. Generally, it is cooled to the most unstable temperature of austenite at a relatively fast speed, and the austenite is transformed into sötenite or sostenite at a relatively fast speed, and the hardness can be reduced.

Recrystallization annealing. It is used to eliminate the hardening phenomenon (increase in hardness and decrease in plasticity) of metal wire rod and sheet in the process of cold drawing and cold rolling. The heating temperature is generally 50 150 below the temperature at which the steel begins to form austenite, and only in this way can the work hardening effect be eliminated and the metal softened.

Graphitization annealing. It is used to turn cast iron containing a large amount of cementite into malleable cast iron with good plasticity. The process operation is to heat the casting to about 950, and cool it properly after holding it for a certain period of time, so that the cementite decomposes into flocculent graphite.

Diffusion annealing. It is used to homogenize the chemical composition of alloy castings and improve their performance. The method is to heat the casting to the highest possible temperature without melting, and keep it warm for a long time, until the diffusion of various elements in the alloy tends to be evenly distributed.

Cool down slowly. Stress relief annealing. It is used to relieve the internal stress of steel castings and weldments. For steel products that begin to form austenite after heating below the temperature of 100 200, after heat preservation and cooling in the air, the internal stress can be eliminated.

Of course, it's softer, it's tougher, and you still need to ask about it.

Summary. The hardness of pure copper after annealing is how much it is unannealed.

Dear, according to your description, the teacher gave it to you in the form of **!

Hope it helps! Have a great day!

Summary. Yes, dear.

1. Brass hardness can be measured by Rockwell hardness tester RTD700, Vickers hardness tester VTD405 or WHB-3000.

2. Annealing will generally decrease. Depending on whether your temperature is high enough, generally speaking, steel 500 annealing for 1 to 3 hours, the hardness will basically not change much. Above this time or temperature, the hardness decreases.

The hardness of brass is relatively high, and it can not be annealed to reduce the hardness.

Wait a minute, dear.

Yes, kiss 1, brass hardness, can be measured by Rockwell hardness tester RTD700, Vickers hardness tester VTD405 or WHB-3000 2, degraded wide fire will generally be reduced. Depending on whether your temperature is high enough, generally speaking, steel 500 annealing for 1 to 3 hours, the hardness will basically not change much. Above this time or if the sail temperature is disturbed, the hardness is reduced.

Hope it helps, dear.

Copper (i.e. pure copper) has excellent electrical and thermal conductivity, plasticity and good corrosion resistance. It has a wide range of applications in industries such as electronics industry, instrumentation and high-voltage switches. In industrial production, the surface hardness and internal grain size of copper parts are more demanding. Usual.

The annealing process is difficult to meet the requirements. The annealing process is divided into water quenching (water cooling), air cooling and furnace cooling, that is, water is used as the cooling medium for annealing, natural cooling in air and cooling with the furnace in the furnace. The annealing of copper is water-cooled or furnace-cooled, both methods can be used when the annealing temperature is low, and water-cooled is recommended when the annealing temperature is higher than 500 degrees Celsius.

The annealing temperature of copper is different at different temperatures. The higher the annealing temperature, the lower the hardness of copper, and the hardness changes little when it exceeds 550 degrees Celsius. The higher the annealing temperature, the lower the strength of the copper, and the more conducive to pressure processing.

It is concluded that the holding temperature of 390 degrees Celsius during annealing is the best annealing temperature for copper, and the hardness of copper products is better and is conducive to pressure processing. The annealing method can be water quenching or furnace cooling.