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• X52 steel plate surface quality standards that need to be met
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• Reasons for choosing Q690D steel

Improving the EH36 steel plate flaw detection qualification rate

In order to improve the qualified rate of flaw detection of EH36 steel plate, the internal quality of steel slab should be improved, and the segregation degree of each element in the slab should be improved. The following measures can be taken in the steelmaking process.

Improve the cleanliness of molten steel, appropriately reduce the content of P and S, which are easy to segregate elements in EH36 steel plate, w(P) <0.015%, w(S) <0.005%, and reduce the degree of P and S segregation from the total amount of inclusions;

Strengthen the management of the bottom blowing of the ladle, strengthen the cleaning and inspection of the ventilation effect of the bottom blowing air brick of the online ladle, and standardize the amount and timing of the addition of drainage sand, so as to avoid the situation that the bottom blowing is small or blocked and affects the refining;

Strengthen the alloy operation of LF furnace and RH furnace, improve the hit rate of alloy out of LF furnace, and reduce the number of alloy additions and the total amount of alloy added to RH furnace;

It is advisable to control the sedation time of ladle molten steel for 5-15 minutes. Too short sedation time is not conducive to the floating and removal of gas and inclusions, and too long time is easy to form molten steel composition and temperature re-stratification, which is not conducive to steady-state pouring;

For the EH36 steel plate, medium and low superheat pouring and electromagnetic stirring technology are adopted, and the heat temperature is preferably 12~25 ℃, so as to reduce the occurrence of columnar crystal "bridging" and billet bulging during solidification;

The EH36 steel plate adopts a reasonable secondary cooling system, and the casting speed matching ensures that the surface temperature of the slab at the straightening point is not less than 940 ℃. Straightening without a liquid core as much as possible can also reduce the probability of cracking in the center of the EH36 steel plate slab.