25-40mm specification Q235 pockmark control process

Abstract

The invention discloses a 25-40mm specification Q235 pockmark control process, and relates to the technical field of steel production. The process comprises the steps that a Q235B steel type furnace charging plan is optimized and adjusted, and before Q235 steel type rolling, steel types with high surface quality requirements and thick plates with the specification being 40mm or above are not arranged; the condition of a rolling mill descaling header nozzle is replaced and checked regularly; according to the adjusted equipment condition, descaling processes of Q235B steel types with different thicknesses are redesigned; the Q235B steel types with different thicknesses are tracked, and the rolling control time is adjusted; and the surface quality conditions of steel plates under different finish rolling temperatures are analyzed, and the finish rolling starting process and the finish rolling process are adjusted according to the performance allowance of the steel plates. By adjusting the related rolling processes, 25-40mm specification Q235B surface pockmarks are reduced, the surface quality of the steel plates is improved, and the pockmark defects are reduced.

Description

technical field [0001] The invention relates to the technical field of iron and steel production, in particular to a 25-40mm specification Q235 hemp pit control process. Background technique [0002] With the development of the national economy and the increasingly severe economic situation, the requirements for product quality are getting higher and higher. Although the automation level of production equipment has been improved and the quality stability has been improved, customers' requirements for surface quality and physical quality are constantly improving. At present, in the rolling production process of steel mills, the judgment rate due to pits is high, which seriously affects the overall unplanned indicators, has a great impact on economic benefits, and seriously affects contract delivery, causing customer complaints. [0003] The analysis of pitting defects found that: 1. High heating temperature leads to serious surface oxidation, thicker oxide skin, which is eas...

AI Technical Summary

Problems solved by technology

Although the automation level of production equipment has improved and the quality stability has improved, customers' requirements for surface quality and physical quality are constantly improving

At present, in the rolling production process of steel mills, the judgment rate due to pits is high, which seriously affects the overall unplanned indicators, has a great impact on economic benefits, and seriously affects the contract delivery, causing customers to complain

[0003] The analysis of pitting defects found that: 1. High heating temperature leads to serious surface oxidation, thicker oxide skin, which is easy to cause pitting; 2. The longer the controlled rolling time, on the one hand leads to poor temperature uniformity of steel, on the other hand, the degree of oxidation Deepening, the secondary oxide scale is thicker, which is not conducive to removal; 3. The current descaling system has an unreasonable design, and there are certain problems in nozzle height, coincidence degree and striking depth; 4. The temperature of the opening and final rolling directly affects the tertiary oxidation of the steel plate, During the straightening process, the oxide scale produced by the third oxidation is pressed into the surface of the steel plate during straightening to cause pitting defects

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