Normalizing treatment of Q235A plate

Q235A plate normalizing and annealing are similar, but the cooling speed slightly, organization is fine.

Some critical cooling rate (see quenching), small steel in air cooling can make austenite into martensite, this does not belong to nature of normalizing treatment, and is called air cooling quenching.

Critical cooling rate, on the contrary, the larger the big cross section of steel production artifacts, do not even when you are in the water quenching martensite, quenching effect close to normalizing. Hardness is higher than annealing after normalizing.

Q235A normalizing without parts like annealing furnace cooling, take up the stove time is short, high production efficiency, so in production is usually as far as possible with normalizing annealing instead. For mild steel Q235A carbon content lower than 0.25%, to moderate hardness after normalizing, annealing than easier to machining, generally are used for cutting work is fire.

To 0.25 ~ 0.5% carbon, medium carbon steel, after normalizing can also meet the requirements of machining. For light load in this kind of steel parts, normalizing also can be used as the final heat treatment. High carbon tool steel and bearing steel is a fire is to eliminate the carbide network in the organization, and preparing spheroidizing annealing for organization.

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