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Pickling Technology

- Aug 16, 2018 -

Pickling technology

  1. Requirements and acceptance of hot rolled steel coilGeneral requirements for cold rolled blank are as follows:

    1.1 the chemical composition of steel shall conform to the national standards;Effect of different components in forming:

    (1) carbon (c): carbon is the most common reinforcing element in steel. Carbon increases strength and decreases plasticity. However, for steel used for forming, low yield strength, high uniform elongation and total elongation are needed. Accordingly with the carbon content of the steel stamping hope is low, general stamping steel carbon content less than 0. 1%, commonly used for C < 0. 08% (e.g., 08 a1) in China, the quality of stamping steel C < 0. 04% (such as our country K08A1), super deep drawing copper (IF steel) is to C (o. 005%, for steel production using oxygen blowing converter, minimum carbon content up to C < 0. 04%, so in terms of smelting must adopt new technology to reduce the content of carbon.

    (2) nitrogen (N): nitrogen generally increases yield strength and tensile strength in steel, increases hardness value, and decreases r value and causes aging. For stamping steel, nitrogen ACTS as carbon, mainly causing yield effect and strain aging. In addition, if the process is not controlled properly, nitrogen will form angular inclusions with titanium and aluminum, which is not good for stamping. As a result, stamping steel always has to reduce nitrogen content to as low as possible.

    (3) aluminum (A1): aluminum is generally added as a deoxidizer in quality stamping steel, and its main function is to remove the oxygen dissolved in the steel solution during oxygen blowing smelting. In addition, A1, as an oxygen determining agent, inhibits the solid solution of nitrogen in ferrite, eliminates the strain aging and improves the low temperature plasticity.

    (4) oxygen (0): oxygen is an indispensable nanometer in steelmaking, but it has a strong affinity with many other elements and is easy to form various inclusions in steel, which is unfavorable to steel performance. In addition, too much oxygen can affect other elements. For example, when Ti is added to steel to fix carbon and nitrogen, if 0< 0.015%, {111} of sodium is strong while {100 is weak, and the r value is high, but when 0> 0.015%, {111} texture strength drops suddenly and r value drops suddenly.