Chinese United steel net Zhuangao: September 1st morning at about 10, the new No. 1 BF of Benxi Steel (4747m3) burst hearth burning through accident, a time of rising market sentiment, is generally believed that at least 3 month overhaul, on the effect of iron was 9 thousand tons, and may even trigger a nationwide safety investigation, then hot rolled futures soaring rose 4.4% to 4251 yuan on the same day, the spot quickly followed, Shanghai 5.5 coil quickly pull up 200 yuan to 4340 yuan / ton. 

After the incident, more than the market speculation, however, today the latest news that a new BF in Benxi Iron and steel will resume production this month 16, 3 months of maintenance time than the original market expected shortened to half a month, at the same time it is maintenance of 2850 blast furnace will be 10 days ahead of the resumption of production, so the effects of the accident further drop. 

It is understood that the refractory material is an important material in the blast furnace must be used, with refractory material quality, masonry, improper use or the quality of raw materials and many other factors that could cause the damage, once damaged, the temperature will rise in blast furnace, to have a fever through the accident. The measure of blast furnace hearth temperature with heat flux and bottom temperature index two, the heat flux is calculated according to the bottom of the cooling water temperature and flow, according to the national standard, when the heat flux intensity of more than 6000 square metres / card should be paid attention to, more than 8000 kcal / square meters need protection of blast furnace, more than 10000 wanka / m2 need to overhaul. Bottom temperature and thermocouple (temperature sensor) buried depth, usually buried deeper, the higher the temperature, but also related with the bottom refractory material thickness, generally high bottom temperature that bottom refractory thinning, need to be replaced. 

Hearth burn need long to resume production depends on the location and extent of damage and burning through steel technology, in 1980 the domestic hearth burning through accident and recovery time, different mills different BF vary greatly, the fastest hours can resume production, some lasted for half a year. 

In addition, since 1980 especially after 2000 by combing the domestic hearth burning through accident, the accident occurred in the industry profit is better time, such as 2002 to 2004 a total of 4, during the annual sales profit rate of key steel enterprises were 5.1%, 7.5% and 8.2%, 2006 and 2007, the accident occurred during the year. Key steel enterprises sales profits were 6.3% and 6.7%, this year 1-7 month sales profit rate is 3.4%, the best level since 2009.