摘要:
A plurality of finishing mills for finish rolling a rolled material are located in a row to configure a finishing mill group. First to third surface coolers for cooling surfaces of the rolled material are located on an entry side of each of first, second and third finishing mills of the finishing mill group, and the amount of cooling water jetted at the rolled material by each surface cooler under a command of a controller is set at 4,000 liters/min.multidot.m.sup.2, whereby the thickness of scale is restricted to 5 .mu.m or less.
摘要:
An alloying system for a galvanized steel sheet, the alloying system using an induction heating coil, wherein an impedance matching apparatus is provided between the induction heating coil and a high frequency power source. The impedance matching apparatus comprises a matching transformer having a plurality of intermediate contact points for arbitrarily selecting a turn ratio, and a switching device for alternative changeover of the intermediate contact point, whereby even when the load impedance of the steel sheet varies, maximum power source output is obtained, such that an appropriate heating temperature necessary for forming an alloy layer of the steel sheet can be supplied.
摘要:
An improved method and a skid member for minimizing the temperature difference between a skid-contacting region and other regions in a hot material to be heated such as a slab or billet within a reheating furnace and a skid apparatus using the same. The skid member has at least one ventilation channel for restraining heat transfer toward a lower portion of the skid member for supporting or carrying the hot material in the reheating furnace and allowing passage of hot gas through the same to reduce the temperature difference between a contact region and a non-contact region of the hot material. The invention restrains heat transfer from the hot material to a skid coolant pipe and introduces hot gas within the reheating furnace into the skid member to compensate heat loss in an upper portion of the skid member, thereby preventing temperature drop in a contact region between a top face of the skid member and an underside of the hot material so that the rolling threading ability and quality of the hot material can be improved in subsequent processes.
摘要:
An apparatus and a method for suppressing growth of an oxide film on a coil which is a spirally wound, rolled strip are disclosed. A rolled strip subjected to rolling by hot rolling equipment is wound spirally by a down-coiler to make a coil. Covers are disposed on the opposite sides of the coil such that heat resistant materials intimately contact the opposite sides of the coil. The covers are fixed by L-bolts and nuts to cover the opposite sides of the coil with the covers. In this state, the coil is naturally cooled for a predetermined time to suppress growth of an oxide film and increase productivity.
摘要:
A system and a method are disclosed for preventing scale defects during hot rolling by hot rolling equipment having a scale breaker provided at an entry side of a finishing mill line composed of a plurality of rolling mills arranged in tandem. A descaler is provided between a first stage rolling mill and a second stage rolling mill of the finishing mill line. A cooler for cooling a hot rolled steel plate is provided between the second stage rolling mill and a third stage rolling mill of the finishing mill line. A control device is provided for controlling the descaler and the cooler to be selectively driven such that neither of the descaler and the cooler is actuated, one of the descaler and the cooler is actuated, or both of the descaler and the cooler are actuated, according to rolling conditions. Thus, the hot rolled steel plate is rolled, with its oxide film thickness at an entry side of the third stage rolling mill being restricted to not more than a limiting oxide film thickness of 5 &mgr;m. Consequently, scale defects are prevented, and overcooling of the hot rolled steel plate is suppressed, to improve the quality of a product.
摘要:
A plurality of finishing mills for finish rolling a rolled material are arranged in a row to construct a finishing mill group, 1st to 3rd surface coolers for cooling the surfaces of the rolled material are provided on the entrance side of the 1st to 3rd finishing mills of the fishing mill group, and the range of cooling of the rolled material by the surface coolers are set to be a range of 0.3 to 1.5 m toward the upstream side from a position separated by 1.5 m or less from the center of the work rolls of each of the finishing mills toward the entrance side of each of the finishing mills.
摘要:
A plurality of finishing mills for finish rolling a rolled material are arranged in a row to form a finishing mill group. A scale breaker is provided at an entry side of the finishing mill group, a glass coating material application device for jetting molten glass to upper and lower surfaces of the rolled material to form a molten glass film is located at a delivery side of the scale breaker, and a molten glass film removing device for removing the molten glass film formed on the upper and lower surfaces of the rolled material is located at the delivery side of the finishing mill group.